Patent Grant
9610674
The present technology is generally related to control valves for waterjet systems, control-valve actuators, waterjet systems (e.g., abrasive jet systems), and methods for operating waterjet systems.
Waterjet systems (e.g., abrasive jet systems) are used in precision cutting, shaping, carving, reaming, and other material-processing applications. During operation, waterjet systems typically direct a high-velocity jet of fluid (e.g., water) toward a workpiece to rapidly erode portions of the workpiece. Abrasive material is typically added to the fluid to increase the rate of erosion. When compared to other material-processing systems (e.g., grinding systems, plasma-cutting systems, etc.) waterjet systems can have significant advantages. For example, waterjet systems often produce relatively fine and clean cuts, typically without heat-affected zones around the cuts. Waterjet systems also tend to be highly versatile with respect to the material type of the workpiece. The range of materials that can be processed using waterjet systems includes very soft materials (e.g., rubber, foam, leather, and paper) as well as very hard materials (e.g., stone, ceramic, and hardened metal). Furthermore, in many cases, waterjet systems are capable of executing demanding material-processing operations while generating little or no dust, smoke, and/or other potentially toxic byproducts.
In a typical waterjet system, a pump pressurizes fluid to a high pressure (e.g., 40,000 psi to 100,000 psi or more). Some of this pressurized fluid is routed through a cutting head that includes an orifice element having an orifice. The orifice element can be a hard jewel (e.g., a synthetic sapphire, ruby, or diamond) held in a suitable mount (e.g., a metal plate). Passing through the orifice converts static pressure of the fluid into kinetic energy, which causes the fluid to exit the cutting head as a jet at high velocity (e.g., up to 2,500 feet-per-second or more) and impact a workpiece. After eroding through a portion of a workpiece, the jet typically is dispersed in a pool of fluid held within a catcher (e.g., a catcher tank) positioned below the workpiece, thereby causing the kinetic energy of the jet to dissipate. A jig including spaced apart slats can be used to support the workpiece over the catcher safely and non-destructively. The jig, the cutting head, the workpiece, or a combination thereof can be movable under computer and/or robotic control such that complex processing instructions can be executed automatically.
Certain materials, such as composite materials, brittle materials, certain aluminum alloys, and laminated shim stock, among others, may be difficult to process using conventional waterjet systems. For example, when a jet is directed toward a workpiece, the jet may initially form a cavity in the workpiece and hydrostatic and/or stagnation pressure from fluid within the jet may act on sidewalls of the cavity. This can cause weaker parts of composite materials to preferentially erode. In the case of layered composite materials, for example, hydrostatic and/or stagnation pressure from a jet may erode binders between layers within the workpiece and thereby cause the layers to separate. Similarly, in the case of fiber-containing composite materials, hydrostatic and/or stagnation pressure from a jet may exceed the bond strength between the fibers and the surrounding matrix, which can also cause delamination. As another example, when a jet is directed toward a workpiece made of a brittle material (e.g., glass), the load on the workpiece during piercing may cause the workpiece to spall and/or crack. Similarly, spalling, cracking, or other damage can occur when jets are used to form particularly delicate structures in both brittle and non-brittle materials. Other properties of jets may be similarly problematic with respect to certain materials and/or operations.
One conventional technique for mitigating collateral damage to a workpiece (e.g., a workpiece made of a composite and/or brittle material) includes piercing the workpiece with a jet formed at a relatively low pressure and then either maintaining the low pressure during the remainder of the processing or ramping the pressure upward after piercing the workpiece. At relatively low pressures, waterjet processing is often too slow to be an economically viable option for large-scale manufacturing. Furthermore, conventional techniques for ramping pressures upward can also be slow and typically decrease the operational life of at least some components of conventional waterjet systems. For example, at least some conventional techniques for ramping pressure upward include controlling a pump and/or a relief valve of a waterjet system to increase the pressure of all or substantially all of the pressurized fluid within the waterjet system. This causes a variety of components of the waterjet system (e.g., valves, seals, conduits, etc.) to be repeatedly exposed to the fluid at both low and high pressures. Over time, this pressure cycling can lead to fatigue-related structural damage to the components, which can cause the components to fail prematurely. Greater numbers of pressure cycles and greater pressure ranges within each cycle can exacerbate these negative effects. The costs associated with such wear (e.g., frequent part replacements, other types of maintenance, and system downtime) tend to make such approaches impractical for most applications. For example, in material-processing applications that involve repeatedly cycling a jet between piercing and cutting operations and/or starting and stopping a jet (e.g., to form spaced-apart openings in a workpiece made of a composite or brittle material), the associated cycling of fluid pressure can cause unacceptable wear to conventional waterjet systems and make use of such systems for these applications cost prohibitive.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The relative dimensions in the drawings may be to scale with respect to some embodiments. With respect to other embodiments, the drawings may not be to scale. For ease of reference, throughout this disclosure identical reference numbers may be used to identify identical or at least generally similar or analogous components or features.
Specific details of several embodiments of the present technology are disclosed herein with reference to
Waterjet systems configured in accordance with embodiments of the present technology can at least partially address one or more of the problems described above and/or other problems associated with conventional technologies whether or not stated herein. A waterjet system configured in accordance with a particular embodiment of the present technology includes a control valve positioned relatively near to a waterjet outlet. The control valve can be configured to decrease the pressure of fluid downstream from the control valve while the pressure of fluid upstream from the control valve remains relatively constant. The upstream fluid pressure can remain relatively constant, for example, due to the operation of a relief valve or another suitable component of the system that operates in concert with the control valve. In this way, most if not all portions of a fluid conveyance within the system can be protected from fatigue damage associated with pressure cycling even while the system executes intricate operations that call for modulating (e.g., rapidly modulating) the power of a jet exiting the waterjet outlet. Many technical challenges and solutions associated with implementing such a system and related technology are described in detail below.
As used herein, the term “piercing,” unless the context clearly indicates otherwise, refers to an initial striking, penetration, or perforation of a workpiece by a jet. As an example, piercing may include removing a portion of a workpiece with a jet to a predetermined or non-predetermined depth and in a direction that is at least generally aligned with (e.g., parallel to) a longitudinal axis of the jet. As another example, piercing may include forming an opening or hole in an initial outer portion and/or one or more initial outer layers of a workpiece using a jet. As yet another example, piercing may include penetrating completely through a workpiece as a preparatory action prior to cutting a feature (e.g., a slot) in the workpiece. The term “cutting,” unless the context clearly indicates otherwise, generally refers to removal of at least a portion of a workpiece using a jet in a direction that is not at least generally aligned with (e.g., parallel to) a longitudinal axis of the jet. However, in some instances, cutting may also include, after an initial piercing, continued material removal from a pierced region (e.g., an opening) using a jet in a direction that is at least generally aligned with (e.g., parallel to) a longitudinal axis of the jet. The headings provided herein are for convenience only and should not be construed as limiting the subject matter disclosed herein.
Selected Examples of Control Valves
The upstream housing 106 can include a first recess 116 shaped to receive at least a portion of the first seat 102. Similarly, the downstream housing 108 can include a second recess 118 shaped to receive at least a portion of the second seat 104. The second engagement feature 114 can be adjusted (e.g., rotated) in a first direction to reduce the distance or gap between the first and second recesses 116, 118 and thereby releasably secure the first and second seats 102, 104 between the upstream and downstream housings 106, 108 (e.g., in an abutting relationship with one another). Similarly, the second engagement feature 114 can be adjusted (e.g., rotated) in a second direction opposite to the first direction to increase the distance or gap between the first and second recesses 116, 118 and ultimately separate the upstream and downstream housings 106, 108 to thereby release the first and second seats 102, 104 from the control valve 100 (e.g., for replacement, inspection, etc.). The collar 110 can include a first weep hole 120 configured to allow any fluid leakage between the upstream and downstream housings 106, 108 to escape from the control valve 100. The collar 110 can further include an annular groove 122 that passes across an outermost portion of the first weep hole 120 and accepts an o-ring 124.
In the illustrated embodiment, the upstream housing 106 includes a fluid inlet 126 that opens into a first chamber 128 operably positioned adjacent to and upstream from the first seat 102. The upstream housing 106 can further include a third recess 130 and a fourth recess 132, with the fourth recess 132 operably positioned between the first chamber 128 and the third recess 130. The fourth recess 132 can be configured to house a seal assembly (not shown) (e.g., a high-pressure seal assembly including static and/or dynamic sealing components), and the third recess 130 can be configured to house a retainer screw (not shown) configured to secure the seal assembly within the fourth recess 132. Similar to the collar 110, the upstream housing 106 can include a second weep hole 134 configured to allow any fluid leakage through the seal assembly to escape from the control valve 100. Furthermore, the control valve 100 can include a fluid filter (not shown) (e.g., a screen or mesh made of stainless steel or another suitable material) operably positioned in or at least proximate to the fluid inlet 126 or having another suitable position upstream from the first seat 102. In at least some cases, the control valve 100 can be susceptible to damage from particulates within fluid flowing through the control valve 100. The fluid filter can reduce the possibility of such particulates reaching the first and second seats 102, 104.
The control valve 100 can further include an elongate pin 136 (e.g., a tapered, at least generally cylindrical pin with a circular cross-section), a plunger 138, and a cushion 140 operably positioned between the pin 136 and the plunger 138. The pin 136 can include a shaft portion 136a extending through the first chamber 128 and into the first seat 102, an end portion 136b at one end of the shaft portion 136a operably positioned toward the second seat 104, and a base portion 136c at an opposite end of the shaft portion 136a operably positioned toward the cushion 140. In
In some embodiments, the cushion 140 is configured to compress between the base portion 136c of the pin 136 and the plunger 138 when the pin 136 is in the shutoff position and the plunger 138 is at a position of maximum extension. In this way, the cushion 140 can reduce the possibility of the plunger 138 forcing the end portion 136b of the pin 136 against the second seat 104 with excessive force, which has the potential to damage the pin 136 and/or the second seat 104. Suitable materials for the cushion 140 can include, for example, ultra-high-molecular-weight polyethylene, polyurethane, and rubber, among others. In other embodiments, the cushion 140 may be absent and the base portion 136c of the pin 136 and the plunger 138 may directly abut one another or be connected in another suitable manner. Additional details and examples related to controlling actuation of the pin 136, including controlling force between the end portion 136b of the pin 136 and the second seat 104 are provided below.
With reference to
The pin 136 can be movable relative to the first and second seats 102, 104 between the shutoff position and one or more throttling positions in which the end portion 136b of the pin 136 is positioned away from the contact surface 148. For example, the pin 136 can be movable between the shutoff position and two or more throttling positions incrementally or infinitely varied within a range of throttling positions.
Moving the pin 136 from one throttling position to another throttling position can proportionally vary the first and second gaps 152, 154. For example, moving the pin 136 from one throttling position to another throttling position (e.g., left-to-right in
At the high pressures and velocities typically used in waterjet systems, components within waterjet systems can erode rapidly. This erosion can compromise important tolerances or even lead to component failure. Typically, both the speed of a fluid flowing past a solid surface and the surface area of the surface affect its rate of erosion. When the cross-sectional area of a flow passage is restricted for a given pressure, the speed of the fluid increases proportionally with the restriction. With these variables in mind, the shapes of the end portion 136b of the pin 136, the shaft portion 136a of the pin 136, the tapered inner surface 144, and the contact surface 148 can be selected to enhance the operation and/or lifespan of the control valve 100. For example, in most cases, when the pin 136 is at a given throttling position and the second gap 154 is greater than the first gap 152, the speed of the fluid flowing through the first gap 152 is proportionally greater than the speed of the fluid flowing through the second gap 154. The surface areas of the tapered inner surface 144 and the contact surface 148 can be selected to at least partially compensate for differences in erosion associated with these differences in speed. For example, the surface area of the tapered inner surface 144 can be selected to cause the erosion rate of the tapered inner surface 144 and an erosion rate of the contact surface 148 to be within 50% of one another, within 25% of one another, or otherwise at least generally equal. When the erosion rates of the tapered inner surface 144 and the contact surface 148 are at least generally equal, the overall control valve 100 can wear relatively evenly, which can improve the operation of the control valve 100 and/or increase the lifespan of the control valve 100. The surface area of the tapered inner surface 144 can be variable over a wide range by changing the length of the tapered inner surface 144. In general, larger surfaces erode more slowly than smaller surfaces. Thus, the surface area of the tapered inner surface 144 can be selected to be at least 5 times (e.g., within a range from 5 times to 100 times), at least 10 times (e.g., within a range from 10 times to 100 times), at least 20 times (e.g., within a range from 20 times to 100 times), at least another suitable threshold multiple, or within another suitable range of multiples greater than the surface area of the contact surface 148.
With reference to
Relatively high compression force between the end portion 136b of the pin 136 and the contact surface 148 can be advantageous to facilitate complete or nearly complete sealing against fluid flow through the control valve 100. In at least some embodiments, the actuator and the contact surface 148 can be configured such that a compression force between the end portion 136b of the pin 136 and the contact surface 148 is at least 75,000 psi (e.g., within a range from 75,000 psi to 200,000 psi), at least 100,000 psi (e.g., within a range from 100,000 psi to 200,000 psi), at least another suitable threshold force, or within another suitable range of forces when the pin 136 is in the shutoff position. The second seat 104 can be configured to withstand this force. For example, in the illustrated embodiment, the contact surface 148 can be buttressed in a direction parallel to the longitudinal axis 145 of the pin 136 by a wall around the channel 156. The cross-sectional area of the second passage 146 can be smaller along a segment adjacent to and downstream from the contact surface 148 than another segment further downstream from the contact surface 148. The channel 156 can have a cross-sectional area adjacent to the contact surface 148 and perpendicular to the longitudinal axis 145 of the pin 136 less than 75% (e.g., within a range from 10% to 75%), less than 50% (e.g., within a range from 10% to 50%), less than another suitable threshold percentage, or within another suitable range of percentages of a cross-sectional area of the first passage 142 at the first end portion 144a of the tapered inner surface 144 and perpendicular to the longitudinal axis 145 of the pin 136.
As discussed above with reference to
With reference to
In the control valve 100 shown in
As discussed above with reference to
In the embodiment illustrated in
Positioning the contact surface 806 at an upstream end of the passage 804 may facilitate manufacturing the seat 800 as a single piece. Accordingly, in the illustrated embodiment, the seat 800 is at least generally free of seams between the contact surface 806 and the tapered inner surface 144. In other embodiments, the seat 800 can be replaced with an upstream seat including the contact surface 806 and a downstream seat including the tapered inner surface 144 connected in a suitable manner (e.g., as discussed above in the context of connecting the first and second seats 102, 104 shown in
With reference to
Selected Examples of Control-Valve Actuators
Control valves configured in accordance with at least some embodiments of the present technology can include actuators (e.g., linear actuators) that precisely and accurately move a pin to one or more positions relative to a seat and at least generally maintain the pin at the position(s). In some cases, the actuators include electromechanical and/or hydraulic actuating mechanisms alone or in combination with pneumatic actuating mechanisms. In other cases, the actuators can be entirely pneumatic, or be configured to operate by one or more other suitable modalities. Suitable electromechanical actuating mechanisms can include, for example, stepper motors, servo motors with position feedback, direct-current motors with position feedback, and piezoelectric actuating mechanisms, among others. In a particular embodiment, a control valve includes an actuator having a Switch and Instrument Motor Model 87H4B available from Haydon Kerk Motion Solutions (Waterbury, Conn.).
Different types of actuating mechanisms can have different advantages when incorporated into control valves in accordance with embodiments of the present technology. For example, electromechanical and hydraulic actuating mechanisms are typically more resistant to moving in response to variable opposing forces than pneumatic actuating mechanisms. Pneumatic actuating mechanisms, however, typically operate more rapidly than hydraulic actuating mechanisms as well as many types of electromechanical actuating mechanisms. Furthermore, relative to electromechanical actuating mechanisms, pneumatic actuating mechanisms typically are better suited for precisely controlling the level of force on a pin. As discussed in further detail below, actuators configured in accordance with at least some embodiments of the present technology can have one or more features that reduce or eliminate one or more disadvantages associated with conventional actuators in the context of actuating the control valves discussed above with reference to
It can be useful for an actuator to have a combination of different actuating mechanisms. For example, with reference to
In at least some embodiments, the second pneumatic actuating mechanism 1104 can be at least partially inset within the first pneumatic actuating mechanism 1102. For example, the actuator 1100 can include an outer housing 1126 having a central channel 1128 (e.g., cylinder), and an inner housing 1130 at least partially defining the third and fourth enclosures 1116, 1118. The inner housing 1130 can be slidably received within the central channel 1128. The outer housing 1126 can include an annular channel 1132 around the central channel 1128. The channel 1132 can at least partially define the first and second enclosures 1106, 1108. The first piston 1110 can be annular and secured to the inner housing 1130 such that the first piston 1110 and the inner housing 1130 move together. For example, the first and second pneumatic regulators 1112, 1114 can cause a pressure difference on opposite sides of the first piston 1110 that causes the inner housing 1130 and the second piston 1120 (and hence the plunger 1105) to move relative to the outer housing 1126. The third and fourth pneumatic regulators 1122, 1124 can cause a pressure difference on opposite sides of the second piston 1120 that causes the second piston 1120 (and hence the plunger 1105) to move relative to the inner housing 1130 and the outer housing 1126.
The actuator 1100 can be configured to move the pin 136 between a shutoff position, a first throttling position, and at least a second throttling position. For example, the first pneumatic actuating mechanism 1102 can have a fully open position when the pressure in the first enclosure 1106 is greater than the pressure in the second enclosure 1108 causing the inner housing 1130 to move from left to right in
The first pneumatic actuating mechanism 1102 can have a first travel distance 1134 and the second pneumatic actuating mechanism 1104 can have a second travel distance 1136 less than the first travel distance 1134. For example, the first travel distance 1134 can be within a range from 0.05 inch to 0.5 inch, from 0.1 inch to 0.3 inch, or within another suitable range. In a particular embodiment, the first travel distance 1134 is 0.2 inch. The second travel distance 1136 can be, for example, within a range from 0.001 inch to 0.05 inch, from 0.005 inch to 0.015 inch, or within another suitable range. In a particular embodiment, the second travel distance 1136 is 0.01 inch. The ratio of the first travel distance 1134 to the second travel distance 1136 can be, for example, within a range from 5:1 to 50:1, from 10:1 to 30:1, or within another suitable range. In a particular embodiment, the ratio of the first travel distance 1134 to the second travel distance 1136 is 20:1. It can be useful for the first pneumatic actuating mechanism 1102 to be more powerful than the second pneumatic actuating mechanism 1104 for a given pneumatic fluid pressure. Accordingly, in some embodiments, the first piston 1110 has a greater surface area exposed to pneumatic force than the second piston 1120. In other embodiments, the second piston 1120 can have a greater surface area exposed to pneumatic force than the first piston 1110.
With reference to
The plunger guide 1206 can include a central channel 1230 and can be configured to slidingly receive a first end portion 1208a of the plunger 1208 while a second end portion 1208b of the plunger 1208 is secured to the piston 1204 within the central bore 1218. For example, the plunger 1208 at the second end portion 1208b and the piston 1204 at the central bore 1218 can include complementary first threads 1231. In the illustrated embodiment, the first end portion 1208a of the plunger 1208 is slidingly received within a smooth bushing 1232 of the plunger guide 1206 inserted into the central channel 1230. The plunger guide 1206 can further include a stepped recess 1233 extending around the central channel 1230 and facing toward the second end 1202b. The stepped recess 1233 can have a first portion 1233a spaced apart from the central channel 1230 and a concentric second portion 1233b positioned between the first portion 1233a and a perimeter of the central channel 1230. The second portion 1233b can be more deeply inset into the plunger guide 1206 than the first portion 1233a, and can be configured to receive the spring assembly 1207. The second end portion 1208b of the plunger 1208 can be part of a stepped-down segment 1234 of the plunger 1208, and the plunger 1208 can further include a ledge 1236 adjacent to the stepped-down segment 1234 as well as a circumferential groove 1238 operably positioned between the ledge 1236 and the first threads 1231. The piston 1204 can be configured to contact the ledge 1236 around a perimeter of the central bore 1218 when the stepped-down segment 1234 is fully secured to the piston 1204.
The actuator 1201 can be assembled, for example, by inserting the piston 1204 (e.g., with the plunger 1208 secured to the piston 1204) into the actuator housing 1202 via the major opening 1210 and subsequently inserting the plunger guide 1206 into the actuator housing 1202 via the major opening 1210. Screws (not shown) (e.g., set screws) can be individually inserted through holes 1239 in the sidewall 1216 and into threaded recesses 1240 (one shown) distributed around the circumference of the first portion 1206a of the plunger guide 1206 to secure the plunger guide 1206 in position. The actuator 1201 can further include a retaining ring 1242 (e.g., a flexible gasket, a radially expandable clamp, or another suitable component) operably positioned between the lip 1212 and the first portion 1206a of the plunger guide 1206. The retaining ring 1242 can reduce vibration of the plunger guide 1206 during use or have another suitable purpose. The plunger guide 1206 can include a second edge recess 1244 and a second sealing member 1246 (e.g., an o-ring) operably positioned within the second edge recess 1244. Similarly, the plunger 1208 can include a third edge recess 1248 and a third sealing member 1250 (e.g., an o-ring) operably positioned within the third edge recess 1248. The second sealing member 1246 can be configured to engage the sidewall 1216 to form a fixed pneumatic seal, and the third sealing member 1250 can be configured to slide along an inner surface of the central channel 1230 to form a movable pneumatic seal. In conjunction with the first sealing member 1224, the second and third sealing members 1246, 1250 can be configured to pneumatically seal the first enclosure 1226.
The actuator 1201 can further include a first pneumatic port 1252 and a second pneumatic port 1254 operably connected to the first and second enclosures 1226, 1228, respectively. In some embodiments, the actuator 1201 is configured to be controlled by changing the pressure of gas (e.g., air) within the first enclosure 1226 while the pressure of gas (e.g., air) within the second enclosure 1228 remains at least generally constant. In other embodiments, the actuator 1201 can be configured to be controlled by changing the pressure of gas within the second enclosure 1228 while the pressure of gas within the first enclosure 1226 remains at least generally constant, by changing the pressures of gases within both the first and second enclosures 1226, 1228, or by another suitable procedure. Furthermore, one or both of the first and second enclosures 1226, 1228 can be replaced with non-pneumatic mechanisms. For example, the first enclosure 1226 can be replaced with a hydraulic mechanism and/or the second enclosure 1228 can be replaced with a hydraulic mechanism or a mechanical spring, as discussed in greater detail below.
The piston 1204 can be configured to move back and forth within the actuator housing 1202 from a first end position 1255a to a second end position 1255b and through a range of travel 1255 (indicated by a horizontal line in
The actuator 1201 can be configured to change the spacing between the seat 900, or another suitable seat configured in accordance with an embodiment of the present technology, and an elongate pin 1260 of the control valve 1200. For example, the actuator 1201 can be configured to change the spacing between a minimum spacing 1261a and a maximum spacing 1261b and through a range of spacing 1261 (indicated by a horizontal line in
With reference to
In some embodiments, the actuator 1201 includes a non-pneumatic mechanism in place of or in addition to the second enclosure 1228. For example, the actuator 1201 can include a hydraulic mechanism configured to exert a consistent or variable hydraulic force or a mechanical spring configured to exert a consistent or variable spring force against the piston 1204 in the second direction 1258 in place of or in addition to the second pneumatic force (PF2). Like pneumatic force, hydraulic and spring forces can remain at least generally constant when corresponding displacement is abruptly obstructed (e.g., when the pin 1260 contacts the seat 900). As discussed above, however, pneumatic actuating mechanisms typically operate more rapidly than hydraulic actuating mechanisms and can have other advantages when used in waterjet systems. Relative to pneumatic force, spring force from a mechanical spring can be more difficult to adjust and can complicate design or operation of the actuator 1201 by changing relative to displacement of the piston 1204.
The plunger 1208 can include an adjustment bushing 1264 and a plug 1266 operably positioned within the adjustment bushing 1264. A position of a contact interface 1267 between the plunger 1208 and the pin 1260 can be adjustable relative to a position of the piston 1204 along an adjustment axis (not shown) parallel to the first and second directions 1256, 1258. For example, the plug 1266 can have a convex end portion 1268 that abuts a complementary concave end portion 1269 of the pin 1260 at the contact interface 1267. The position of the plug 1266 can be adjustable relative to the adjustment bushing 1264 along the adjustment axis. The adjustment bushing 1264 and the plug 1266 can include complementary second threads 1270, and the plug 1266 can be rotatable relative to the adjustment bushing 1264 to adjust the position of the contact interface 1267. The plug 1266 can include a socket 1272 (e.g., a hexagonal socket) shaped to receive a wrench or other suitable tool to facilitate this adjustment. Adjusting the position of the contact interface 1267 can be useful, for example, to at least partially compensate for manufacturing irregularities in the pin 1260 or to otherwise facilitate calibration of the control valve 1200 after initial installation or replacement of the pin 1260 and/or the seat 900. In at least some cases, controlling the position of the contact interface 1267 along the adjustment axis using the second threads 1270 can be more precise than a manufacturing tolerance of the length of the pin 1260. In a particular embodiment, the diameter of the plug 1266 is 0.25 inch. The density of the second threads 1270 along the adjustment axis can be, for example, greater than 20 threads-per-inch (e.g., from 20 threads-per-inch to 200 threads-per-inch), greater than 40 threads-per-inch (e.g., from 40 threads-per-inch to 200 threads-per-inch), greater than 60 threads-per-inch (e.g., from 60 threads-per-inch to 200 threads-per-inch), greater than another suitable threshold, or within another suitable range. For example, the density of the second threads 1270 along the adjustment axis can be 80 threads-per-inch.
The spring assembly 1207 can include a resilient member 1274 configured to exert a spring force (SF) that at least partially counteracts the second pneumatic force (PF2). For example, the resilient member 1274 can be configured to exert the spring force (SF) against the piston 1204 when the piston 1204 is within a first portion 1255c (to the left of a dashed vertical line intersecting the range of travel 1255 in
Although useful to cause the seat contact force (CFs) to be at least generally consistent, counteracting the hydraulic force (HF) with a pneumatic force can also be problematic with respect to maintaining a consistent spacing between the seat 900 and the pin 1260. For example, in waterjet applications, after a particular intermediate spacing (e.g., corresponding to a desired pressure of fluid downstream from the seat 900) is achieved, it is typically desirable to at least generally maintain the spacing for a period of time during a cutting operation. The spacing and/or the hydraulic force (HF), however, typically fluctuate to some degree during this time due to vibration (e.g., associated with operation of a pump upstream from the control valve 1200) and/or other factors. Depending on the relationship between the hydraulic force (HF) and the spacing, this fluctuation can tend to destabilize the spacing when the hydraulic force (HF) is counteracted with pneumatic force. The actuator 1201 can be configured to use the resilient member 1274 to partially or completely overcome this problem.
In some embodiments, the resilient member 1274 is operably positioned within the first enclosure 1226 (e.g., the resilient member 1274 can be a compression spring operably positioned within the first enclosure 1226). In other embodiments, the resilient member 1274 can have another suitable location. For example, the resilient member 1274 can be operably positioned within the second enclosure 1228 (e.g., the resilient member 1274 can be an expansion spring operably positioned within the second enclosure 1228). The resilient member 1274 can also have a variety of suitable forms. With reference to
Belleville springs can be well suited for use in the actuator 1201 due to their relatively compact size, their desirable spring characteristics, and/or due to other factors. In some at least some embodiments, the first and second Belleville springs 1274a, 1274b individually can have a maximum deflection within a range from 0.01 inch to 0.05 inch, from 0.02 inch to 0.04 inch, or within another suitable range. In a particular embodiment, the first and second Belleville springs 1274a, 1274b individually have a maximum deflection of 0.03 inch. Instead of or in addition to Belleville springs, other embodiments can include other suitable types of mechanical springs (e.g., coil springs and machined springs, among others). For example, the first and second Belleville springs 1274a, 1274b can be replaced with one or more rings of coil springs partially inset within the plunger guide 1206. Furthermore, the first and second Belleville springs 1274a, 1274b and/or other suitable resilient members can be secured to a side of the piston 1204 facing toward the plunger guide 1206 rather than to a side of the plunger guide 1206 facing toward the piston 1204.
At a first portion 1261c (
At given intermediate spacings 1261x (indicated by vertical lines in
The resilient member 1274 discussed above with reference to
At the leftmost portion of the plot in
Achieving a second pneumatic force (PF2) of sufficient magnitude to at least generally prevent fluid from flowing through the control valve 1200 can be challenging. For example, when standard pneumatic pressures are used (e.g., 90 psi) within the second enclosure 1228, it can be difficult to achieve a second pneumatic force (PF2) of sufficient magnitude without making the actuator 1201 unduly large. The actuator 1201 can be operably connected to a cutting head (not shown) within a movable waterjet assembly. In at least some cases, decreasing the size of the actuator 1201 can enhance the maneuverability of the waterjet assembly relative to a workpiece (also not shown), a robotic arm (also not shown), and/or other objects coupled to or otherwise proximate to the waterjet assembly. For example, when the cutting head is tiltable, decreasing the size of the actuator 1201 can increase the tiltable range of the cutting head. Furthermore, using pressures greater than standard pneumatic pressures can significantly increase the cost and complexity of the actuator 1201. The resilient member 1274 can have one or more properties that reduce or eliminate this problem. For example, the resilient member 1274 can have an at least generally linear spring characteristic rather than a progressive spring characteristic (i.e., the rate of increase in the spring force (SF) can be at least generally constant within the first portion 1255c of the range of travel 1255 rather than increasing as the piston 1204 approaches the first end position 1255a). Alternatively, the resilient member 1274 can have a degressive spring characteristic (i.e., the rate of increase in the spring force (SF) can decrease within the first portion 1255c as the piston 1204 approaches the first end position 1255a). Belleville springs, for example, often have degressive spring characteristics.
With reference to
In some embodiments, the first pneumatic force (PF1) is initially stepped-up (e.g., by rapidly increasing the pneumatic input to the actuator 1201 to the second pressure) such that the total force (TF) becomes positive and the piston 1204 accelerates in the first direction 1256 until the spacing stabilizes at a suitable level corresponding to a selected initial steady-state pressure of fluid downstream from the seat 900. In other embodiments, the pneumatic input to the actuator 1201 can be increased from the first pressure to the second pressure at a rate of change selected to cause a gradual increase in the pressure of fluid downstream from the seat 900 toward the initial steady-state pressure. The achievable initial steady-state pressure can be infinitely or nearly infinitely variable. Furthermore, the pneumatic input to the actuator 1201 can be changed at a rate selected to cause a suitable rate of ramp-up or ramp-down to or from the initial steady-state pressure. Furthermore, the pneumatic input to the actuator 1201 can be continuously ramped up and/or down in a stable manner without ever achieving a steady-state pressure of fluid downstream from the seat 900.
When the first pneumatic force (PF1) is increased to a level sufficient to cause the spacing to enter the second portion 1261d, the piston 1204 can be released from the spring force (SF), which can cause the total force (TF) to become positive, and the piston 1204 to accelerate in the first direction 1256 while the spacing increases through the second portion 1261d and approaches the third portion 1261e. Although stable operation within the third portion 1261e may be possible, in some cases, variation of the spacing within the third portion 1261e may have little or no meaningful effect on the pressure of fluid downstream from the seat 900. Thus, the positive total force (TF) acting against the piston 1204 in the first direction 1256 can be maintained when the spacing reaches the third portion 1261e so as to cause the piston 1204 to continue accelerating in the first direction 1256 while the spacing increases toward the maximum spacing 1261b. To cause the spacing to move toward the maximum spacing 1261b more rapidly, the magnitude of the second pneumatic force (PF2) in the second direction 1258 can be decreased (e.g., to zero) while the first pneumatic force (PF1) is maintained or increased. This can increase the total force (TF) in the first direction 1256 and thereby increase the acceleration of the piston 1204 in the first direction 1256. For example, rather than increasing the pressure of gas within the first enclosure 1226 to increase the first pneumatic force (PF1) in the first direction 1256, the pressure of gas within the second enclosure 1228 can be decreased (e.g., to atmospheric pressure) to decrease the magnitude of the second pneumatic force (PF2) in the second direction 1258.
In some cases, the second pneumatic force (PF2) is maintained when the piston 1204 is at the second end position 1255b and the magnitude of the housing contact force (CFh) in the second direction 1258 is equal the positive difference between the magnitude of the second pneumatic force (PF2) in the second direction 1258 and the sum of the first pneumatic force (PF1) and the hydraulic force (HF). In other cases, the second pneumatic force (PF2) can be zero when the piston 1204 is at the second end position 1255b and the magnitude of the housing contact force (CFh) in the second direction 1258 can be equal to the sum of the first pneumatic force (PF1) and the hydraulic force (HF). In still other cases, the first pneumatic force (PF1) can be decreased to zero after decreasing the magnitude of the second pneumatic force (PF2) in the second direction 1258 such that the magnitude of the housing contact force (CFh) in the second direction 1258 is equal to the hydraulic force (HF) only.
Although
Furthermore, although
When the actuator 1201 is configured to achieve intermediate spacings 1261x by varying the pressure of gas within the second enclosure 1228, the second pneumatic port 1254 can be connected to a high-precision and/or high-accuracy pneumatic regulator (as discussed in further detail below). To increase the spacing from the minimum spacing 1261a to a suitable intermediate spacing 1261x, the pressure of gas within the second enclosure 1228 can be decreased precisely (e.g., to a precise level and/or at a precise rate). To increase the spacing to the maximum spacing 1261b, the pressure of gas within the second enclosure 1228 can be rapidly decreased to atmospheric pressure (e.g., dumped). In at least some cases, when the actuator 1201 is configured to achieve intermediate spacings 1261x by varying the pressure of gas within the second enclosure 1228, the actuator 1201 does not achieve the maximum spacing 1261b as rapidly as when the actuator 1201 is configured to achieve intermediate spacings 1261x by varying the pressure of gas within the first enclosure 1226 (e.g., because the total force (TF) acting against the piston 1204 in the first direction 1256 is lower when the first pneumatic force (PF1) is lower). Thus, in these cases, it can be useful for the actuator 1201 to be configured to achieve intermediate spacings 1261x by varying the pressure of gas within the second enclosure 1228 when compactness is more important than opening speed, and for the actuator 1201 to be configured to achieve intermediate spacings 1261x by varying the pressure of gas within the first enclosure 1226 when opening speed is more important than compactness.
In addition to or instead of incorporating resilient members to enhance stability of operation, actuators configured in accordance with at least some embodiments of the present technology can be stabilized electronically using suitable control algorithms.
After stabilizing at an initial spacing between the seat 900 and the pin 1260 corresponding to an initial steady-state pressure of fluid downstream from the seat 900, the initial spacing can be maintained for a period (e.g., while a first portion of a waterjet cutting operation is performed). The spacing can then be changed to achieve another suitable steady-state pressure of fluid downstream from the seat 900, which can then be maintained for another period (e.g., while a second portion of a waterjet cutting operation is performed). Such variation can also be continuous rather than incremental. For example, the waterjet system 1400 can be configured to vary the spacing and the corresponding pressure of fluid downstream from the seat 900 continuously according to a suitable control algorithm. The waterjet system 1400 can include a controller 1405 (e.g., a proportional-integral-derivative controller) operably associated with the actuator 1402 and with the pressure sensor 1403. The controller 1405 can be configured to execute a feedback control loop that increases the positional stability of the pin 1260 while the spacing between the seat 900 and the pin 1260 is maintained or while the spacing is varied in a controlled manner. For example, the pressure sensor 1403 can be configured to detect a pressure of the fluid downstream from the seat 900 and to communicate the detected pressure to the controller 1405 as an input to the feedback control loop. The feedback control loop can cause the actuator 1402 to change a force exerted against the pin 1260 in response to the input. In this way, the force from the actuator 1402 can be automatically adjusted to compensate for destabilizing forces, such as the fluctuations 1284 described above with reference to
In addition to or instead of the pressure sensor 1403, the waterjet system 1400 can include one or more other types and/or placements of sensors configured to provide input to the feedback control loop. For example, with reference to
The waterjet system 1400 can further include a pressure sensor 1415. In the illustrated embodiment, the pressure sensor 1415 is operably connected to the actuator 1402 at the first side 1204a of the piston 1204. In other embodiments, the pressure sensor 1415 can be operably connected to the actuator 1402 at the second side 1204b of the piston 1204 or have another suitable position. The pressure sensor 1415 can be operably associated with the controller 1205. For example, the pressure sensor 1415 can be configured to detect a pneumatic pressure at the first side 1204a of the piston 1204 and to communicate the detected pneumatic pressure to the controller 1405 as the input to the feedback control loop.
With reference to
Although the pressure sensors 1403, 1415, the force sensor 1406, and the position sensor 1416 are all included in the embodiment shown in
With reference again to
Controlling the actuator 1402 by controlling a pneumatic input at a side of the piston 1204 at which an exerted force tends to open the control valve 1401 can advantageously enhance the stability of the control valve during operation in at least some cases. For example, in some embodiments, the actuator 1402 is controlled primarily or entirely via the first pneumatic regulator 1421 and the second pneumatic regulator 1422 closes off the second enclosure 1228 such that gas is trapped at the first side 1204a of the piston 1204. The second pneumatic regulator 1422, for example, can be a relief valve configured to be either fully open or fully closed. Force at the first side 1204a of the piston 1204 may tend to close the control valve 1401 and force at the second side 1204b of the piston 1204 may tend to open the control valve 1401. The trapped gas at the first side 1204a of the piston 1204 can act as an air spring that delays or otherwise diminishes the effect of destabilizing forces, such as the fluctuations 1284 described above with reference to
As discussed above, the controller 1405 can be configured to control and/or monitor operation of the control valve 1401, such as to cause the control valve 1401 to execute instructions entered manually by a user at the user interface 1420 and/or to automatically stabilize operation of the control valve 1401. The controller 1405 can include a processor 1424 and memory 1426 and can be programmed with instructions (e.g., non-transitory instructions) that, when executed using the processor 1424, cause a desired change in operation of the system 1400. For example, the instructions can cause a change in a pneumatic input to the actuator 1402 based at least in part on input from the pressure sensor 1403, the force sensor 1406, the pressure sensor 1415, the position sensor 1416, and/or another suitable sensor of the system 1400. In addition to or instead of receiving input from one or more sensors associated with the control valve 1401, the controller 1405 can be configured to receive input from other components of the waterjet system 1400. For example, the controller 1405 can be operably associated with a fluid-pressurizing device (e.g., a pump) (not shown) that is configured to pressurize fluid upstream from the control valve 1401. One or more operating parameters of the fluid-pressurizing device (e.g., rpm, electrical load, and output flow rate, among others) can be communicated to the controller 1405 as input to the feedback control loop. In at least some cases, this input and the other types of input described above can be at least partially redundant. Thus, the waterjet system 1400 can be configured to utilize fewer (e.g., one, two or three) of the described types of input.
The control valve 1401 can be configured to default to a closed position so as not to open unexpectedly in the event of a pneumatic failure, sensor failure, or other disruption. For example, the first pneumatic regulator 1421 can default to a closed position and the second pneumatic regulator 1422 can default to an open position. When the controller 1405 uses measurement of an indirect variable (e.g., the pressure within the first or second enclosure 1226, 1228 of the actuator 1402) as input to the feedback control loop, the correlation between the indirect variable and the corresponding variable (e.g., the pressure of fluid within the control valve 1401) can be recalibrated regularly. Other precautions can also be taken to improve the reliability of the input. For example, when the pressure within the first or second enclosure 1226, 1228 of the actuator 1402 is used as the input, the first or second enclosure 1226, 1228, respectively, can be leak tested between calibrations.
The waterjet system 1400 can be configured to be calibrated before use instead of or in addition to utilizing feedback. For example, calibration can be used to ascertain a pressure of gas within the first enclosure 1226 that causes a desired pressure (e.g., 10,000 psi) of fluid downstream from the seat 900 when the pressure upstream from the control valve 1401 is at desired system pressure (e.g., 60,000 psi). After calibration, the first pneumatic regulator 1421 can be used to maintain the ascertained pressure of gas within the first enclosure 1226 so as to cause the desired pressure of fluid downstream from the seat 900 as needed. One example of a suitable calibration method includes first adjusting the output flow rate of the fluid-pressurizing device (e.g., according to a correlation by which the output flow rate is linearly proportional to the rpm of the fluid-pressurizing device) while the control valve 1401 is fully opened until the desired pressure of fluid downstream from the seat 900 is achieved. With the control valve 1401 fully opened, the pressure of fluid upstream from the control valve 1401 can be the same as the pressure of fluid downstream from the seat 900. Next, without changing the output flow rate of the fluid-pressurizing device, the pressure of gas within the first enclosure 1226 can be increased gradually using the first pneumatic regulator 1421 to close the control valve 1401 while the pressure of fluid upstream from the control valve 1401 is monitored. In at least some cases, when the pressure of fluid upstream from the control valve 1401 reaches the desired system pressure, the corresponding pressure of gas within the first enclosure 1226 may be the pressure that causes the desired pressure of fluid downstream from the seat 900 when the pressure of fluid upstream from the control valve 1401 is at the desired system pressure so long as the pressure of gas within the second enclosure 1228 is consistent during calibration and subsequent use. The pressure of gas within the second enclosure 1228 can be maintained at 85 psi, 90 psi, or at another suitable level. Calibrating the waterjet system 1400 in this manner can be useful, for example, to correct for variability in the erosion of the pin 1260 and the seat 900 and/or dimensional variability in replaced components, among other factors.
The actuator 1502 can further include a first movable member, such as a first piston 1518, and a second movable member, such as a second piston 1520, both movably positioned within the actuator housing 1504. Furthermore, the actuator 1502 can include a first plunger 1522 coupled to the first piston 1518 and configured to move with the first piston 1518 in parallel with the actuating axis 1506, and a second plunger 1524 coupled to the second piston 1520 and configured to move with the second piston 1520 in parallel with the actuating axis 1506. For example, the actuator 1502 can include a first plunger guide 1526 having a first central channel 1528 configured to slidingly receive the first plunger 1522, and a second plunger guide 1530 having a second central channel 1532 configured to slidingly receive the second plunger 1524. The actuator 1502 can be assembled, for example, by inserting the first plunger guide 1526 into the actuator housing 1504 via the second major opening 1514, then inserting the first piston 1518 (e.g., with the first plunger 1522 secured to the first piston 1518) into the actuator housing 1504 via the second major opening 1514, then inserting the second piston 1520 (e.g., with the second plunger 1524 secured to the second piston 1520) into the actuator housing 1504 via the second major opening 1514, and then inserting the second plunger guide 1530 into the actuator housing 1504 via the second major opening 1514. Screws (not shown) (e.g., set screws) can be individually inserted through holes 1533 in the sidewall 1216 and into threaded recesses 1534 (one shown) distributed around the circumference of the first plunger guide 1526 to secure the first plunger guide 1526 in position within the actuator housing 1504.
The first piston 1518 can be cylindrical (e.g., disk-shaped) and can include a central bore 1535 and a fourth sealing member 1538 (e.g., an o-ring) inset within a fourth edge recess 1536. The fourth sealing member 1538 can be configured to slide along an inner surface of the sidewall 1216 to form a movable seal. The first plunger guide 1526 can be configured to slidingly receive a portion of the first plunger 1522 while another portion of the first plunger 1522 is secured to the first piston 1518 within the central bore 1535. In a particular embodiment, the first plunger 1522 is slidingly received within the bushing 1232 inserted into the first central channel 1528. The first plunger guide 1526 can include a fifth edge recess 1544 and a fifth sealing member 1546 (e.g., an o-ring) operably positioned within the fifth edge recess 1544. Similarly, the first plunger 1522 can include a sixth sealing member 1550 (e.g., an o-ring) operably positioned within a sixth edge recess 1548. The fifth sealing member 1546 can be configured to engage the inner surface of the sidewall 1216 to form a fixed seal, and the sixth sealing member 1550 can be configured to slide along the inner surface of the bushing 1232 to form a movable seal.
The second piston 1520 and the second plunger guide 1530, respectively, can be similar to the piston 1204 and the plunger guide 1206 discussed above with reference to
The first piston 1518 and the second piston 1520 can be configured to move in parallel with the actuating axis 1506 in the actuating direction 1508 or in the direction opposite to the actuating direction 1508 in response to changes in one or more pressure equilibriums (e.g., pneumatic and/or hydraulic pressure differentials) between different enclosures within the actuator housing 1504. In one embodiment, the actuator 1502 includes a first space 1553 within the actuator housing 1504 between the first plunger guide 1526 and the first piston 1518, a second space 1554 within the actuator housing 1504 between the second plunger guide 1530 and the second piston 1520, and a third space 1556 within the actuator housing 1504 between the first and second pistons 1518, 1520. Furthermore, the actuator 1502 can include a first pneumatic port 1558, a second pneumatic port 1560, and a third pneumatic port 1562 opening into the first space 1553, the second space 1554, and the third space 1556, respectively. The first and second pneumatic ports 1558, 1560 can extend through the first and second plunger guides 1526, 1530, respectively, and can be stationary during operation of the actuator 1502. In some embodiments, the third pneumatic port 1562 is movable in parallel with the actuating axis 1506 during operation of the actuator 1502. For example, the third pneumatic port 1562 can extend through the first plunger 1522. In other embodiments, the third pneumatic port 1562 can extend through the second plunger 1524 or have another suitable position. As shown in
The first piston 1518 can be movable from a fully retracted first position (
The actuator 1502 can be controlled by, for example, changing pneumatic inputs to the first, second, and/or third pneumatic ports 1558, 1560, 1562. In an example of operation, when the pin 136 is in the closed position (
To move the pin 136 to the throttling position (
To move the pin 136 to the open position (
As shown in
As shown in
The piston assembly 1708 can include an annular piston member 1718 and a central piston member 1720 slidably disposed within a central region of the annular piston member 1718. In some embodiments, the annular piston member 1718 and the central piston member 1720 can be functional substitutes for the first and second pistons 1518, 1520 described above with reference to
In the illustrated embodiment, the plunger 1715 and the central piston member 1720 are integrally connected. In other embodiments, the plunger 1715 and the central piston member 1720 can be separate structures coupled to one another. The third central bore 1722 can be aligned with a longitudinal channel 1737 within the plunger 1715. The longitudinal channel 1737 can have a wide portion 1737a closest to the central piston member 1720 and a narrow portion 1737b further from the central piston member 1720. The plunger 1715 can include a plug 1738 operably positioned within the second central bore 1712 and the wide portion 1737a of the longitudinal channel 1737. The outer surface of the plug 1738 can be threaded and the plug 1738 can be rotatably disposed within the second central bore 1712 and the wide portion 1737a of the longitudinal channel 1737 such that the threads engage complementary threads along an inner surface of the second central bore 1712 and the wide portion 1737a of the longitudinal channel 1737. In this way, the plug 1738 can be adjusted in a manner similar to the manner in which the plug 1266 shown in
As shown in
The position of the pin 136 in the throttle state can be adjusted, for example, by rotating one of the first and second portions 1706a, 1706b of the plunger guide 1706 relative to the other at a rotational interface 1750. The first portion 1706a of the plunger guide 1706 can include one or more sockets 1752 (one shown in
To move the pin 136 from the closed position to the open position or from the throttling position to the open position, the pneumatic pressure in the first space 1740 can be released while the pneumatic pressure provided via the first pneumatic port 1746 is maintained. As the piston assembly 1708 moves toward the second end 1704b, the flange 1731 can separate from the fifth sealing member 1736 and the second and third spaces 1742, 1744 can combine. When the pin is in the open position, the central piston member 1720 can be at least partially nested within the concavity 1705 to enhance compactness. In some embodiments, the actuator 1702 is configured to change the position of the pin 136 between the closed position, the open position, and a manually adjusted throttle position. In other embodiments, the actuator 1702 can be configured to change the position of the pin 136 between the closed position, the open position, and an automatically adjusted throttle position. Automatic adjustment of the throttle position can be accomplished, for example, using a servomechanism (not shown) configured to cause rotation at the threaded interface 1750 (e.g., in a manner similar to the manner discussed above with reference to
Selected Examples of Relief Valves
When a jet is slowed or stopped using a control valve configured in accordance with an embodiment of the present technology, it can be useful to at least generally prevent fluid pressure upstream from the control valve from increasing in response, even for a very short period of time. In some embodiments, a waterjet system including a control valve includes a pressure-compensated pump, such as a hydraulic intensifier that responds (e.g., goes off stroke) automatically when fluid pressure upstream from the control valve changes due to operation of the control valve. In other embodiments, a waterjet system including a control valve includes a pump that is not pressure-compensated, such as a positive-displacement pump (e.g., a direct-drive pump) that may not be capable of automatically responding to changes in fluid pressure upstream from the control valve due to operation of the control valve. For example, positive-displacement pumps may have relatively high inertia during operation that cannot be rapidly redirected. A waterjet system that includes a pump that is not pressure-compensated and a control valve configured in accordance with an embodiment of the present technology can include a relief valve configured to release fluid when a jet generated by the system is slowed or stopped using the control valve. As an example, the relief valve can be configured to open and/or close in response to input associated with operation of the control valve (e.g., one or more signals corresponding to at least partially opening and/or closing the control valve). As another example, the relief valve can be configured to automatically open and/or close in response to a change in a balance of opposing forces acting on a portion of the relief valve, with the change being associated with operation of the control valve.
The valve body 1802 can include a cylindrical seal housing 1808 extending from an annular internal ledge 1810 toward the threaded opening 1806. The seal housing 1808 can be configured to hold a seal assembly (not shown) (e.g., a suitable high-pressure seal assembly including static and/or dynamic sealing components) with the retainer screw holding the seal assembly against the internal ledge 1810. The valve body 1802 can further include a first weep hole 1812 opening to the fluid inlet 1804, and a second weep hole 1814 opening to an annular groove 1816 operably positioned between the threaded opening 1806 and the seal housing 1808. The first weep hole 1812 and the second weep hole 1814 can be configured to allow any fluid leakage proximate the fluid inlet 1804 and the seal housing 1808, respectively, to exit the relief valve 1800.
In the illustrated embodiment, the relief valve 1800 includes a cylindrical chamber 1818 adjacent to the seal housing 1808, and a fluid outlet 1820 extending laterally (e.g., radially) outward from the chamber 1818. The relief valve 1800 can further include a seat 1822 operably positioned within the valve body 1802 between the fluid inlet 1804 and the chamber 1818. In some embodiments, the seat 1822 is fixedly attached (e.g., pressed, welded, or bolted) within the valve body 1802. In other embodiments, the seat 1822 can be releasably held in place within the valve body 1802 by a conduit or other component (e.g., as discussed above) connected to the valve body 1802 at the fluid inlet 1804. The seat 1822 can include a central channel 1824 (e.g., a bore) and a tapered inner surface 1826 along at least a portion of the channel 1824. For example, the channel 1824 can have a cross-sectional area that decreases along the tapered inner surface 1826 from the chamber 1818 toward the fluid inlet 1804. The channel 1824 can include a flared portion 1824a (e.g., a conical portion) proximate to the fluid inlet 1804, and an intermediate portion 1824b positioned between the flared portion 1824a and an end of the tapered inner surface 1826 closest to the fluid inlet 1804.
The relief valve 1800 can further include an elongate stem 1828 moveably positioned within the valve body 1802. The stem 1828 can include a pin portion 1830 operably positioned toward a first end portion 1828a of the stem 1828, a connector shaft 1834 operably positioned toward a second end portion 1828b of the stem 1828, and a flow restrictor 1832 positioned therebetween. The pin portion 1830 can have an outer surface tapered inwardly toward the first end portion 1828a relative to a longitudinal axis 1836 of the stem 1828. The taper of the outer surface of the pin portion 1830 can be at least generally complementary (e.g., parallel) to the taper of the seat 1822. In at least some embodiments, for example, the taper of the pin portion 1830 and the taper of the seat 1822 can be angled within a range from 0.01 degree to 2 degrees, from 0.1 degree to 0.59 degree, from 0.1 degree to 0.5 degree, or within another suitable range of angles relative to the longitudinal axis 1836 of the stem 1828. For example, the outer surface of the pin portion 1830 and the tapered inner surface 1826 of the seat 1822 can both be angled at 0.5 degree relative to the longitudinal axis 1836 of the stem 1828.
In the illustrated embodiment, the relief valve 1800 includes a plunger 1840 operably coupling an actuator 1838 (shown schematically) to the connector shaft 1834. In operation, the actuator 1838 can exert a closing force against the stem 1828 via the plunger 1840 to drive (e.g., press) the stem 1828 toward the seat 1822 and/or move the stem 1828 away from the seat 1822. In some embodiments, the plunger 1840 is aligned with the connector shaft 1834, but not secured to the connector shaft 1834. In other embodiments, the connector shaft 1834 can be secured to the plunger 1840 (e.g., screwed into the end of the plunger 1840), which can allow the actuator 1838 to pull the stem 1828 away from the seat 1822 in addition to pushing the stem 1828 toward the seat 1822.
In use, pressurized fluid upstream from the pin portion 1830 can exert an opening force against the pin portion 1830. If the actuator 1838 exerts a constant closing force against the stem 1828, an increase in upstream fluid pressure acting against the pin portion 1830 (e.g., due to at least partially closing a control valve) can cause the relief valve 1800 to automatically open. Similarly, when the pressure of the upstream fluid decreases (e.g., due to at least partially opening a control valve), the opening force acting against the pin portion 1830 can decrease and the relief valve 1800 can automatically close. The actuator 1838 can be configured such that a maximum extension of the plunger 1840 and/or the maximum closing force acting on the stem 1828 is less than an extension and/or force, respectively, that would cause the pin portion 1830 to become jammed in the channel 1824 (e.g., that would cause static friction between the outer surface of the pin portion 1830 and the tapered inner surface 1826 of the seat 1822 to exceed the maximum opening force acting against the pin portion 1830 during normal operation). Furthermore, the actuator 1838 can be configured to release the closing force automatically when a fluid-pressurizing device (e.g., a pump) (not shown) that pressurizes the upstream fluid is shut off. This feature can enable the upstream fluid to automatically depressurize via the relief valve 1800 upon shutdown of the fluid-pressurizing device. The actuator 1838, for example, can include an electrically actuated air valve configured to release pneumatic pressure when the associated fluid-pressurizing device is shutdown.
Conventional relief valves used in high-pressure systems typically open when an upstream fluid reaches a first (e.g., opening) pressure, and then equilibrate when the upstream fluid reaches a second (e.g., equilibrium) pressure greater than the opening pressure. For example, the equilibrium pressure can be from 2% to 8% greater than the opening pressure. Without wishing to be bound by theory, it is expected that the phenomenon that causes this observed difference between the opening pressure and the equilibrium pressure may be associated with fluid flowing through a conventional relief valve transitioning from laminar flow to turbulent flow as the flow rate of the fluid increases. This transition may decrease the drag exerted by the fluid against the stem of a conventional relief valve and thereby decrease the total opening force acting against the stem. Since an actuator of a conventional relief valve typically exerts a constant closing force against a stem, the upstream fluid pressure may increase after the laminar-to-turbulent flow transition until it reaches a pressure high enough to compensate for the decreased drag force acting on the stem. The position of the stem then equilibrates at this higher pressure. Decreasing drag force acting against a stem of a conventional relief valve is only one example of a possible mechanism to explain observed differences between opening pressures and equilibrium pressures. Other mechanisms instead of or in addition to this mechanism may account for the phenomenon and various mechanisms may apply to some sets of operational parameters (e.g., pressures and fluid flow rates) and not others. Other possible mechanisms include, for example, localized decreases in pressure proximate upstream portions of stems and static friction between stems and corresponding seats.
Operating a high-pressure system (e.g., to produce a jet) while a conventional relief valve is open typically is not desirable. The fluid in such a system, therefore, is effectively only useable at pressures lower than the opening pressure so that the conventional relief valve remains closed. Components (e.g., valves, seals, conduits, etc.) of the system, however, still typically must be rated for the higher equilibrium pressure since they are exposed to the equilibrium pressure when the conventional relief valve is open. Exposing these system components to pressure cycling and higher equilibrium pressures caused by operation of conventional relief valves can necessitate the use of more expensive components (e.g., having higher pressure ratings) without providing any operational advantage (e.g., greater jet velocity). Furthermore, even when higher equilibrium pressures do not necessitate using more expensive components, over time, exposure to these pressures and the accompanying pressure cycling can cause structural damage (e.g., fatigue-related structural damage) in the components, which can be detrimental to the operation of the components and/or cause the components to fail prematurely.
In contrast to conventional relief valves, relief valves configured in accordance with at least some embodiments of the present technology can reduce or eliminate the phenomenon of higher equilibrium pressure than opening pressure. With reference again to
With reference to
In operation, flow restriction through the second passage 1848 can cause a pressure differential on opposite sides of the flow restrictor 1832. For example, a fluid pressure within a portion of the chamber 1818 upstream from the flow restrictor 1832 can be higher than a fluid pressure within a portion of the chamber 1818 downstream from the flow restrictor 1832. This pressure difference alone or in combination with other opening force acting against the flow restrictor 1832 (e.g., drag from the fluid) can at least partially compensate for a decrease in the opening force acting against the pin portion 1830 when the relief valve 1800 moves from the first operational state toward the third operational state and/or when the relief valve 1800 moves from the second operational state toward the third operational state. The cross-sectional area of the second passage 1848 perpendicular to the longitudinal axis 1836 of the stem 1828, alone or together with other suitable parameters, can be selected to partially compensate, fully compensate, or overcompensate for the a decrease in the opening force acting against the pin portion 1830 when the relief valve 1800 moves from the first operational state toward the third operational state and/or when the relief valve 1800 moves from the second operational state toward the third operational state. In at least some embodiments, the cross-sectional area of the second passage 1848 perpendicular to the longitudinal axis 1836 of the stem 1828 is within a range from 3 times to 50 times, from 5 times to 30 times, from 160 times to 25 times, or within another suitable range of multiples greater than the cross-sectional area of the first passage 1842 perpendicular to the longitudinal axis 1836 of the stem 1828 when the stem 1828 is in the third position and the relief valve 1800 is in the third operational state.
The opening force can include a first opening force acting against the pin portion 1830 and a second opening force acting against the flow restrictor 1832. The cross-sectional area of the second passage 1848 perpendicular to the longitudinal axis 1836 of the stem 1828, alone or together with other suitable parameters, can be selected such that a difference between the second opening force when the stem 1828 is in the second position and the second opening force when the stem 1828 is in the third position is equal to or greater than a difference between the first opening force when the stem 1828 is in the second position and the first opening force when the stem 1828 is in the third position. Similarly, the cross-sectional area of the second passage 1848 perpendicular to the longitudinal axis 1836 of the stem 1828, alone or together with other suitable parameters, can be selected such that a difference between the second opening force when the stem 1828 is in the first position and the second opening force when the stem 1828 is in the third position is equal to or greater than a difference between the first opening force when the stem 1828 is in the first position and the first opening force when the stem 1828 is in the third position.
With reference to
With reference to
With reference to
Table 2 (below) shows several examples of values for parameters of the stem 2300 (e.g., the minimum diameter of the pin portion 2301, the minimum cross-sectional area of the pin portion 2301, the diameter of the hole 2306, the diameter of the flow restrictor 2302, and the cross-sectional area of the flow restrictor 2302), examples of values for parameters of a system including a relief valve including the stem 2300 (e.g., the system pressure), examples of experimentally obtained values (e.g., the observed pressure increase without the flow restrictor 2302, the flow rate through the relief valve when relief valve is open), examples of values derived from parameters of the stem 2300, parameters of the system, and/or experimentally obtained values (e.g., the force due to the observed pressure increase, the pressure difference across the flow restrictor 2302, and the force due to the flow restrictor 2302). These examples of values are shown for a system including a 50 horsepower pump and for a system including a 100 horsepower pump. In other embodiments, the values shown in Table 2 can be different.
Table 2 demonstrates that various parameters of the stem 2300 can be selected to cause the flow restrictor 2302 to equally compensate for a particular increase in system pressure (e.g., an increase empirically determined by opening a relief valve without a flow restrictor). Variations of the values shown in Table 2 can be used to select suitable cross sectional areas of the second passages (or other suitable parameters) of the relief valves discussed above with reference to
As discussed above with reference to
In at least some cases, generating the input, receiving the input at the controller 2404, and controlling the actuator 1838 in response to the input can occur rapidly enough to allow electronic control to substitute partially or entirely for the functionality of the flow restrictor 1832 shown in
In at least some embodiments, the controller 2404 is configured to instruct the actuator 1838 to decrease a force applied to the stem 2402 via the plunger 1840 as the relief valve 2400 opens so as to decrease the difference between the pressure of fluid upstream from the relief valve 2400 sufficient to initially open the relief valve 2400 and the pressure of fluid upstream from the relief valve 2400 sufficient to maintain the relief valve 2400 in an open state at equilibrium. The amount by which the controller 2404 instructs the actuator 1838 to decrease the force can be pre-specified and fixed. For example, a pneumatic input to the actuator 1838 can be controlled using a resistance-based pneumatic regulator (not shown) having an inline switching resistor that decreases the force by a set increment (e.g., 5,000 psi) in response to an instruction from the controller 2404 (e.g., corresponding to a “jet-on” condition). Alternatively, this amount can be variable and controllable to allow a user to make adjustments in the field. For example, the amount of the decrease can be controlled using a potentiometer that a user can adjust as needed. In another embodiment, the controller 2404 is configured to instruct the actuator 1838 to decrease the first force by a user-adjustable increment communicated to the controller 2404 via the user interface 2408.
Accordingly, while the flow restrictor 1832 shown in
Selected Examples of Waterjet Systems
The fluid conveyance 2512 can extend between components of the system 2500 that are typically stationary during operation (e.g., the main fluid-pressurizing device 2508) and components of the system 2500 that typically move during operation (e.g., relative to a workpiece to execute a cut). In at least some embodiments, the fluid conveyance 2512 can span a distance greater than 20 feet (e.g., within a range from 20 feet to 200 feet), greater than 40 feet (e.g., within a range from 40 feet to 200 feet), greater than another suitable threshold, or within another suitable range. To withstand high pressures, components of the fluid conveyance 2512 can be relatively rigid. For example, the fluid conduit 2518 can be a metal pipe with an outer diameter of ⅜ inch and an inner diameter of ⅛ inch. The movable joint 2522 can facilitate a transition from stationary components to movable components in addition to or instead of any flexibility (e.g., play) in the fluid conveyance 2512. Accordingly, the movable joint 2522 can include a high-pressure seal (not shown) that is prone to fatigue-related structural damage due to pressure cycling.
The control valve 2516 can be at least generally similar in structure and/or function to the control valves described above with reference to
The relief valve 2514 can be at least generally similar in structure and function to one or more of the relief valves described above with reference to
The system 2500 can further include an orifice element 2524, a mixing chamber 2526, and a jet outlet 2528, which can be included with the control valve 2516 in a waterjet assembly 2530. The orifice element 2524 and the mixing chamber 2526 can be parts of a cutting head that includes the jet outlet 2528. The system 2500 can include a second actuator 2532 operably connected to the waterjet assembly 2530 and configured to move the waterjet assembly 2530 relative to a workpiece (not shown) during operation of the system 2500. The control valve 2516 can have various suitable positions within the system 2500. In the illustrated embodiment, the control valve 2516 is downstream from the movable joint 2522 and within the waterjet assembly 2530. The second actuator 2532 can be configured to move the waterjet assembly 2530 over an area greater than 10 square feet (e.g., from 10 square feet to 5000 square feet), greater than 22 square feet (e.g., from 20 square feet to 5000 square feet), greater than 50 square feet (e.g., from 50 square feet to 5000 square feet), greater than 100 square feet (e.g., from 100 square feet to 5000 square feet), greater than another suitable threshold area, or within another suitable range of areas. Furthermore, the control valve 2516 can be less than 50 inches (e.g., within a range from 0.5 inch to 50 inches), less than 25 inches (e.g., within a range from 0.5 inch to 25 inches), less than 20 inches (e.g., within a range from 0.5 inch to 20 inches), less than 15 inches (e.g., within a range from 0.5 inch to 15 inches), less than 10 inches (e.g., within a range from 0.5 inch to 10 inches), less than 5 inches (e.g., within a range from 0.5 inch to 5 inches), less than 2 inches (e.g., within a range from 0.5 inch to 2 inches), less than 1 inch (e.g., within a range from 0.5 inch to 1 inch), less than another suitable threshold distance, or within another suitable range of distances from the jet outlet 2528 and/or the workpiece.
The second actuator 2532 can be configured to move the waterjet assembly 2530 along a processing path (e.g., cutting path) in two or three dimensions and, in at least some cases, to tilt the waterjet assembly 2530 relative to the workpiece. The processing path can be predetermined, and operation of the second actuator 2532 can be automated. For example, the system 2500 can include a controller 2534 having a user interface 2536 (e.g., a touch screen) and a controller 2538 with a processor (not shown) and memory (also not shown). The controller 2534 can be operably associated with the control valve 2516 and the second actuator 2532 (e.g., via the controller 2538). The control valve 2516 can be configured to receive one or more first signals 2540 (e.g., electronically communicated data) from the controller 2534 and to vary the flow rate of the fluid passing through the control valve 2516 in response to the first signals 2540 to change the pressure of the fluid upstream from the orifice element 724 and thereby change the velocity of the fluid exiting the jet outlet 2528. Similarly, the second actuator 2532 can be configured to receive one or more second signals 2542 (e.g., electronically communicated data) from the controller 2534 and to move the waterjet assembly 2530 along the processing path in response to the second signals 2542. Furthermore, the controller 2534 can include one or more of the control features described above with reference to
The user interface 2536 can be configured to receive input from a user and to send data 2543 based on the input to the controller 2538. The input can include, for example, one or more specifications (e.g., coordinates or dimensions) of the processing path and/or one or more specifications (e.g., material type or thickness) of the workpiece. The controller 2534 can be configured to generate the first and second signals 2540, 2542 at least partially based on the data 2543. For example, the controller 2534 can be configured to generate the first signals 2540 at least partially based on a remaining portion of the workpiece after processing is complete (e.g., an inverse of the processing path). In some cases, the remaining portion includes one or more narrow portions (e.g., bridging portions between closely spaced cuts). The controller 2534 can be configured to identify the narrow portions and to instruct the control valve 2516 via the first signals 2540 to reduce the flow rate of the fluid passing through the control valve 2516 and thereby reduce the pressure of the fluid upstream from the orifice element 724 and the velocity of the fluid exiting the jet outlet 2528 at portions of the processing path adjacent to the narrow portions. This can be useful, for example, to reduce the likelihood of the narrow portions breaking due to the impact force of the fluid during the cuts.
The controller 2534 can also be configured to instruct the second actuator 2532 via the second signals 2542 to reduce the rate of movement of the waterjet assembly 2530 along the portions of the processing path adjacent to the narrow portions to compensate for a slower cutting velocity of the jet when the flow rate of the fluid flowing through the control valve 2516 is lowered. Accordingly, the rate of movement of the waterjet assembly 2530 and the flow rate of the fluid flowing through the control valve 2516 can be suitably coordinated to cause an at least generally consistent eroding power along at least a portion of the processing path. Furthermore, the controller 2534 can be configured to instruct the second actuator 2532 via the second signals 2542 to tilt the waterjet assembly 2530 along the portions of the processing path adjacent to the narrow portions (e.g., to reduce taper). Further information concerning using tilt to reduce taper can be found in U.S. Pat. No. 7,035,708, which is incorporated herein by reference in its entirety.
In addition to portions of the processing path adjacent to the narrow portions, other portions of processing paths also may benefit from reduced-velocity jets. For example, some three-dimensional etching applications can include rasterizing a three-dimensional image and cutting a workpiece to different depths as the waterjet assembly 2530 traverses back and forth relative to the workpiece. One approach to controlling the depth is to change the speed of the waterjet assembly 2530 and thereby changing the jet exposure time at different portions of the workpiece. In addition or alternatively, the controller 2534 can be configured to instruct the control valve 2516 via the first signals 2540 to change the flow rate of the fluid passing through the control valve 2516 and thereby change the pressure of the fluid upstream from the orifice element 724 and the velocity of the fluid exiting the jet outlet 2528 to achieve suitable changes in cutting depth for shaping the work piece. Further information concerning three-dimensional etching can be found in U.S. Patent Application Publication No. 2009/0311944, which is incorporated herein by reference in its entirety.
In some cases, the processing path includes two or more spaced-apart cuts individually having a starting point and an ending point. The controller 2534 can be configured to instruct the control valve 2516 via the first signals 2540 to increase the flow rate of the fluid passing through the control valve 2516 and thereby increase the pressure of the fluid upstream from the orifice element 724 and the velocity of the fluid exiting the jet outlet 2528 at the starting points (e.g., in a throttled-piercing operation). Similarly, the controller 2534 can be configured to instruct the control valve 2516 via the first signals 2540 to reduce the flow rate of the fluid passing through the control valve 2516 and thereby reduce the pressure of the fluid upstream from the orifice element 724 and the velocity of the fluid exiting the jet outlet 2528 at the ending points (e.g., in a shut-off operation). Gradually increasing the flow rate of the fluid passing through the control valve 2516 at the starting points can be useful, for example, to reduce the possibility of damaging (e.g., cracking or spalling) the workpiece (e.g., when the workpiece is brittle). In some cases, the starting and ending points for one or more of the spaced-apart cuts individually are at least generally the same (e.g., have at least generally the same coordinates). This can be the case, for example, when the spaced-apart cuts are perimeters of cut-away regions of the workpiece. When many spaced-apart cuts are included in a processing path, and in other cases, it can be useful to shut off a jet rapidly at the end of each cut to improve efficiency. In contrast, as discussed above, it can also be useful to initiate the jet gradually at the beginning of the cut to reduce the possibility of damaging to the workpiece. Accordingly, the controller 2534 can be configured to instruct the control valve 2516 via the first signals 2540 to increase the flow rate of the fluid passing through the control valve 2516 at the starting point at a first rate of change and to decrease the flow rate of the fluid passing through the control valve 2516 at the ending point at a second rate of change greater than the first rate of change. The controller 2534 can be configured to instruct the control valve 2516 via the first signals 2540 to rapidly pulse the flow rate of the fluid passing through the control valve 2516 during piercing, which can also be useful to reduce damage to a workpiece (e.g., workpieces made of brittle and/or composite materials).
The system 2500 can further include an abrasive supply 2544 (e.g., a hopper), an abrasive conduit 2546 operably connecting the abrasive supply 2544 to the mixing chamber 2526, and an abrasive metering valve 2548 along the abrasive conduit 2546. The abrasive conduit 2546 can be flexible or otherwise configured to maintain the connection between the abrasive supply 2544 and the mixing chamber 2526 when the abrasive supply 2544 is stationary and the mixing chamber 2526 is movable with the waterjet assembly 2530. Alternatively, the abrasive supply 2544 can be part of the waterjet assembly 2530. The abrasive metering valve 2548 can be configured to vary the flow rate of abrasive material (e.g., particulate abrasive material) entering the mixing chamber 2526 by a suitable modality (e.g., a supplied vacuum that draws the abrasive material in the mixing chamber 2526, a pressurized feed that pushes the abrasive material into the mixing chamber 2526, or an adjustable abrasive flow passage) alone or in combination with the Venturi effect. Further information concerning abrasive metering valves can be found in U.S. Patent Application Publication No. 2012/0252325 and U.S. Patent Application Publication No. 2012/0252326, which are incorporated herein by reference in their entireties. Alternatively, the abrasive metering valve 2548 can be eliminated. For example, the abrasive material can be drawn into the mixing chamber 2526 by the Venturi effect alone.
The abrasive metering valve 2548 can be operably associated with the controller 2534 (e.g., via the controller 2538). The abrasive supply 2544 can be configured to receive one or more third signals 2550 (e.g., electronically communicated data) from the controller 2534 and to vary the flow rate of abrasive material entering the mixing chamber 2526 in response to the third signals 2550. When the workpiece is brittle, and in other cases, it can be useful to avoid impacting the workpiece with a jet not having entrained abrasive material. A lack of abrasive material at the beginning of a cut, for example, can increase the possibility of damaging the workpiece during piercing. Similarly, a lack of abrasive material at the end of a cut, for example, can increase the possibility of producing an incomplete cut. Accordingly, the controller 2534 can be configured to begin a flow of the abrasive material from the abrasive supply 2544 toward the mixing chamber 2526 a suitable period of time (e.g., 1 second, a period of time within a range from 0.05 to 5 seconds, or a period of time within another suitable range) before the control valve 2516 initiates a throttled-piercing operation and/or to end the flow of the abrasive material from the abrasive supply 2544 toward the mixing chamber 2526 a suitable period of time (e.g., 1 second, a period of time within a range from 0.05 to 5 seconds, or a period of time within another suitable range) after the control valve 2516 completes a shut-off operation. Furthermore, the controller 2534 can be configured to instruct the abrasive metering valve 2548 via the third signals 2550 to change the flow rate of abrasive material entering the mixing chamber 2526 in concert with instructing the control valve 2516 via the first signals 2540 to vary the flow rate of the fluid passing through the control valve 2516 and/or with instructing the second actuator 2532 via the second signals 2542 to reduce the rate of movement of the waterjet assembly 2530 so as to cause an at least generally consistent eroding power along at least a portion of the processing path.
The first, second, and third signals 2540, 2542, 2550 can be accompanied by electronic communication to the controller 2534 (e.g., via the controller 2538) from the control valve 2516, the second actuator 2532, and the abrasive metering valve 2548, respectively. Similarly, the data 2543 can include two-way communication between the user interface 2536 and the controller 2538. When the control valve 2516 includes an actuator having an electric motor (e.g., a stepper motor), the control valve 2516 can be configured to transmit information regarding operation of the motor to the controller 2534. With reference to
The system 2700 can further include a base 2714, a user interface 2716 supported by the base 2714, and a second actuator 2718 configured to move the waterjet assembly 2704 relative to the base 2714 and other stationary components of the system 2700 (e.g., the fluid-pressurizing device 2702). For example, the second actuator 2718 can be configured to move the waterjet assembly 2704 along a processing path (e.g., cutting path) in two or three dimensions and, in at least some cases, to tilt the waterjet assembly 2704 relative to the base 2714. The conduit 2706 can include a joint 2719 (e.g., a swivel joint or another suitable joint having two or more degrees of freedom) configured to facilitate movement of the waterjet assembly 2704 relative to the base 2714. Thus, the waterjet assembly 2704 can be configured to direct a jet including the fluid toward a workpiece (not shown) supported by the base 2714 (e.g., held in a jig supported by the base 2714) and to move relative to the base 2714 while directing the jet toward the workpiece.
The system 2700 can further include an abrasive-delivery apparatus 2720 configured to feed particulate abrasive material from an abrasive material source 2721 to the waterjet assembly 2704 (e.g., partially or entirely in response to a Venturi effect associated with a fluid jet passing through the waterjet assembly 2704). Within the waterjet assembly 2704, the particulate abrasive material can accelerate with the jet before being directed toward the workpiece. In some embodiments the abrasive-delivery apparatus 2720 is configured to move with the waterjet assembly 2704 relative to the base 2714. In other embodiments, the abrasive-delivery apparatus 2720 can be configured to be stationary while the waterjet assembly 2704 moves relative to the base 2714. The base 2714 can include a diffusing tray 2722 configured to hold a pool of fluid positioned relative to the jig so as to diffuse kinetic energy of the jet from the waterjet assembly 2704 after the jet passes through the workpiece. The system 2700 can also include a controller 2724 (shown schematically) operably connected to the user interface 2716, the first actuator 2712, and the second actuator 2718. In some embodiments, the controller 2724 is also operably connected to an abrasive-metering valve 2726 (shown schematically) of the abrasive-delivery apparatus 2720. In other embodiments, the abrasive-delivery apparatus 2720 can be without the abrasive-metering valve 2726 or the abrasive-metering valve 2726 can be configured for use without being operably associated with the controller 2724. The controller 2724 can include a processor 2728 and memory 2730 and can be programmed with instructions (e.g., non-transitory instructions contained on a computer-readable medium) that, when executed, control operation of the system 2700.
The control valve 2808 can be configured to controllably reduce a pressure of fluid within the second portion 2806b of the fluid conveyance 2806 relative to a pressure of fluid within the first portion 2806a of the fluid conveyance 2806, such as to two or more different pressures including a maximum pressure and a reduced pressure. In some embodiments, the control valve 2808 is configured to controllably reduce the pressure of fluid within the second portion 2806b of the fluid conveyance 2806 with infinite or fine incremental variability within a range of pressures. In other embodiments, the control valve 2808 can be configured to controllably reduce the pressure of fluid within the second portion 2806b of the fluid conveyance 2806 to a single reduced pressure or to multiple reduced pressures with coarse increment variability. The shutoff valve 2810 can be configured to shut off the flow of the fluid toward the jet outlet 2804. The system 2800 can further include a relief valve 2812 operably connected to the fluid conveyance 2806 downstream from the fluid source 2802 and upstream from the control valve 2808. The relief valve 2812, for example, can be configured to automatically vary a flow rate of fluid exiting the fluid conveyance 2806 in response to the control valve 2808 controllably reducing the pressure of fluid within the second portion 2806b of the fluid conveyance 2806. The system 2800 can further include a controller 2814 configured to control operation of the control valve 2808, the relief valve 2812, and/or the shutoff valve 2810 using one or more feedback control loops, in response to input from a user communicated via a user interface 2816, and/or in response to an indication of an operational state of another component within the system 2800. The controller 2814 can include a processor 2818 and memory 2820 and can be programmed with instructions (e.g., non-transitory instructions) that, when executed using the processor 2818, cause a change in operation of the control valve 2808, the relief valve 2812, and/or the shutoff valve 2810 based at least in part on the received input.
Any of the control valves, relief valves, actuators, controllers, or other waterjet system components described herein can be substituted for corresponding components shown in
The jet outlet 2804 can be at the end of a cutting head 2832 mounted to a block 2834. The control valve 2808, the second portion 2806b of the fluid conveyance 2806, the shutoff valve 2810, the block 2834, the cutting head 2832, and the jet outlet 2804 can be included in a waterjet assembly 2836 that is movable relative to stationary components of the system 2800. The waterjet assembly 2836 can further include a u-shaped conduit segment 2837 that is part of the first portion 2806a of the fluid conveyance 2806. In at least some embodiments, the fluid source 2802 is stationary and the waterjet assembly 2836 is movable relative to the fluid source 2802. The waterjet assembly 2836 can also be configured to move relative to a stationary workpiece 2838 supported on a series of stationary slats 2840 above a catcher (e.g., a tank containing fluid). In the illustrated embodiment, the waterjet assembly 2836 is movable relative to stationary components of the system 2800 and the workpiece 2838 along a first accordion track 2842 aligned with an x-axis and along a second accordion track 2846 aligned with a y-axis. The first accordion track 2842 can be supported between uprights (not shown) on opposite sides of the catcher and the second accordion track 2846 can be cantilevered from an intermediate junction 2844 along the first accordion track. The waterjet assembly 2836 can further include a z-axis joint 2848 that can be elongated or shortened to move the jet outlet 2804 and nearby portions of the waterjet assembly 2836 relative to other portions of the waterjet assembly 2836. In other embodiments, the waterjet assembly 2836 and portions thereof can be movable in another suitable manner, such as by another suitable mechanism that causes the jet outlet 2804 to be more or less maneuverable than in the illustrated embodiment. For example, in some embodiments, the jet outlet 2804 and nearby portions of the waterjet assembly 2836 are configured to tilt and/or swivel relative to other portions of the waterjet assembly 2836. As another example, the z-axis joint 2848 can be eliminated and the jet outlet 2804 can be movable in unison with the waterjet assembly 2836 in the x-axis and the y-axis only.
The first portion 2806a of the fluid conveyance 2806 can extend through the first and second accordion tracks 2842, 2846 and can be configured to accommodate movement of the jet outlet 2804 relative to stationary components of the system 2800 and the workpiece 2838. For example, the first portion 2806a of the fluid conveyance 2806 can include joints 2850 (e.g., swivel joints) (two shown in
In the illustrated embodiment, the second portion 2806b of the fluid conveyance 2806 is downstream from the control valve 2808. This can cause the second portion 2806b of the fluid conveyance 2806 to be subjected to pressure cycling to a greater extent that the first portion 2806a of the fluid conveyance 2806. In at least some embodiments, the second portion 2806b of the fluid conveyance 2806 includes one or more features that reduce or prevent damage associated with this pressure cycling. For example, the second portion 2806b of the fluid conveyance 2806 can have a greater average pressure rating than the first portion 2806a of the fluid conveyance 2806, such as an average pressure rating at least 50%, at least 100%, or at least 200% greater than the average pressure rating of the first portion 2806a of the fluid conveyance 2806. Furthermore, the second portion 2806b of the fluid conveyance 2806 can have a greater average fatigue resistance than the first portion 2806a of the fluid conveyance 2806, such as an average fatigue resistance at least 50%, at least 100%, or at least 200% greater than the average fatigue resistance of the first portion 2806a of the fluid conveyance 2806.
The second portion 2806b of the fluid conveyance 2806 for example, can be rigid, without movable joints, and/or mostly or entirely made of tubing having specifications (e.g., material type, wall thickness, etc.) selected to enhance fatigue resistance. In the illustrated embodiment, the system 2800 includes a tee junction 2852 downstream from the control valve 2808, a fatigue resistant conduit segment 2854 operably connected to one leg of the tee junction 2852, and a pressure transducer 2856 (shown without internal detail for clarity) operably connected to the opposite leg of the tee junction 2852. The conduit segment 2854 can form an elbow and extend to the shutoff valve 2810. In other embodiments, the second portion 2806b of the fluid conveyance 2806 can have another suitable form between the control valve 2808 and the shutoff valve 2810. The controller 2814 can be configured to receive a detected fluid pressure downstream from the control valve 2808 from the pressure transducer 2856 as input and to use the input in a feedback control loop. Alternatively or in addition, the controller 2814 can communicate input from the pressure transducer 2856 to the user interface 2816 for communication to a user. A user can use information from the pressure transducer 2856, for example, to readily determine the relative eroding power of a jet exiting the jet outlet 2804 in real time or near real time.
The first actuator 2822 can be operably connected to a pin 2900 similar to the pin 302 shown in
As shown in
In the illustrated embodiment, the secondary regulator 2829 allows for unrestricted flow of pneumatic pressure into the third pneumatic port 1562 so as to allow the third space 1556 to be pressurized rapidly thereby allowing the first actuator 2822 to move from the throttle position to the closed position rapidly. The secondary regulator 2829 also restricts flow of pneumatic pressure out of the third pneumatic port 1562 so as to cause the third space 1556 to be depressurized slowly thereby causing the first actuator 2822 to move the control valve 2808 from the close state to the throttle state slowly. In other embodiments, the secondary regulator 2829 can be eliminated and the primary regulator 2908c can be electronically controlled to cause depressurization of the third space 1556 at a controlled rate.
Downstream from the seat 2902, the conduit segment 2854 can be coupled to the tee junction 2852 at one end and to an inlet 3000 of the shutoff valve 2810 at the opposite end. The second actuator 2826 (shown without internal detail for clarity) can include a plunger 3002 and the shutoff valve 2810 can include a pin 3004 with a straight shaft 3004a and a pointed end portion 3004b in line with the plunger 3002. The shutoff valve 2810 can further include a seat 3006 complementary to the pin 3004. When the primary regulator 2908d increases pressure within the pneumatic line 2824d, the second actuator 2826 can drive the pin 3004 toward the seat 3006. The seat 3006 can include a narrow channel 3008 with a rim 3010 that contacts the end portion 3004b of the pin 3004 when the shutoff valve 2810 is closed. The surface area of a contact interface between rim 3010 and the end portion 3004b of the pin 3004 can be relatively small, which can facilitate sealing. When the primary regulator 2908d decreases pressure within the pneumatic line 2824d, the second actuator 2826 can release the pin 3004, thereby allowing unrestricted flow of fluid to exit the shutoff valve 2810 via an outlet 3012.
With reference again to
This disclosure is not intended to be exhaustive or to limit the present technology to the precise forms disclosed herein. Although specific embodiments are disclosed herein for illustrative purposes, various equivalent modifications are possible without deviating from the present technology, as those of ordinary skill in the relevant art will recognize. For example, in the control valves discussed above, the pins can be stationary and the associated seats can be movable or both the pins and the seats can be movable to change the flow rate of fluid passing through the control valves. Similarly, in the relief valves discussed above, the stems can be stationary and the associated seats can be movable or both the stems and the seats can be movable. In some cases, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the present technology. Although steps of methods may be presented herein in a particular order, in alternative embodiments the steps may have another suitable order. Similarly, certain aspects of the present technology disclosed in the context of particular embodiments can be combined or eliminated in other embodiments. Furthermore, while advantages associated with certain embodiments may have been disclosed in the context of those embodiments, other embodiments can also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages or other advantages disclosed herein to fall within the scope of the present technology. Accordingly, this disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
Certain aspects of the present technology may take the form of computer-executable instructions, including routines executed by a controller or other data processor. In at least some embodiments, a controller or other data processor is specifically programmed, configured, and/or constructed to perform one or more of these computer-executable instructions. Furthermore, some aspects of the present technology may take the form of data (e.g., non-transitory data) stored or distributed on computer-readable media, including magnetic or optically readable and/or removable computer discs as well as media distributed electronically over networks. Accordingly, data structures and transmissions of data particular to aspects of the present technology are encompassed within the scope of the present technology. The present technology also encompasses methods of both programming computer-readable media to perform particular steps and executing the steps.
The methods disclosed herein include and encompass, in addition to methods of practicing the present technology (e.g., methods of making and using the disclosed devices and systems), methods of instructing others to practice the present technology. For example, a method in accordance with a particular embodiment includes pressurizing a fluid within an internal volume of a fluid conveyance to a pressure greater than 25,000 psi, directing the pressurized fluid through a control valve operably connected to the fluid conveyance, varying a flow rate of the fluid by throttling the fluid between a shaft portion of a pin and a tapered inner surface of a seat, and impacting the fluid against a workpiece after varying the flow rate of the fluid. A method in accordance with another embodiment includes instructing such a method.
Throughout this disclosure, the singular terms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Similarly, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the terms “comprising” and the like are used throughout this disclosure to mean including at least the recited feature(s) such that any greater number of the same feature(s) and/or one or more additional types of features are not precluded. Directional terms, such as “upper,” “lower,” “front,” “back,” “vertical,” and “horizontal,” may be used herein to express and clarify the relationship between various elements. It should be understood that such terms do not denote absolute orientation. Reference herein to “one embodiment,” “an embodiment,” or similar formulations means that a particular feature, structure, operation, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present technology. Thus, the appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.
This application is a continuation of U.S. application Ser. No. 13/969,477, filed Aug. 16, 2013, now issued as U.S. Pat. No. 8,904,912, which is a continuation-in-part of U.S. application Ser. No. 13/843,317, filed Mar. 15, 2013, and claims the benefit of the following applications: (a) U.S. Provisional Application No. 61/684,133, filed Aug. 16, 2012; (b) U.S. Provisional Application No. 61/684,135, filed Aug. 16, 2012; (c) U.S. Provisional Application No. 61/684,642, filed Aug. 17, 2012; (d) U.S. Provisional Application No. 61/732,857, filed Dec. 3, 2012; and (e) U.S. Provisional Application No. 61/757,663, filed Jan. 28, 2013. The foregoing applications are incorporated herein by reference in their entireties. To the extent the foregoing applications or any other material incorporated herein by reference conflicts with the present disclosure, the present disclosure controls.
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| Number | Date | Country | |
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| 20150151406 A1 | Jun 2015 | US |
| Number | Date | Country | |
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| 61684133 | Aug 2012 | US | |
| 61684135 | Aug 2012 | US | |
| 61684642 | Aug 2012 | US | |
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 13969477 | Aug 2013 | US |
| Child | 14553916 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13843317 | Mar 2013 | US |
| Child | 13969477 | US |
