The present disclosure is generally related to systems and methods for controlling operating pressures of liquid jet cutting systems and, more particularly, to the operation of dump orifices on liquid jet cutting systems.
In liquid jet cutting systems, manually adjustable dump orifices (ADO) are commonly used to maintain operating pressure of the cutting system when the system is in a specific operational state or transitioning between different operational states. For example, an ADO can dump water to maintain system pressure at a desired level when the cutting head nozzle is closed, when the cutting system is between cuts, etc. Conventional ADOs include a hand knob that the operator/technician manually adjusts to set the ADO at a desired position/state.
In practice, some operators find that the hand knob is difficult to access and/or that the ADO adjustment process is tedious. As a result, operators may fail to check and/or manually adjust the ADO as often as necessary, resulting in undesirable spikes and dips in the system pressure during operation which can lead to increased fatigue and premature wear of the high-pressure system components.
The following disclosure describes various embodiments of automatically controlled adjustable dump orifices (ADO) for use with liquid jet cutting systems, such as water jet cutting systems. As described in greater detail below, in some embodiments the automatically controlled ADOs disclosed herein include an electric motor that controls the ADO in response to pressure feedback from the liquid jet cutting system. For example, the motor can be operably connected in a closed-loop control system that monitors liquid pressure or pressures within the liquid jet cutting system (e.g., within the cutting head, the pump, etc.) and utilizes this pressure as feedback or input to control the motor and selectively adjust the setting of the ADO to thereby maintain the pressure in the system at a desired level. In some embodiments, the control system compares the pressure in the liquid jet cutting system to the pressure set point of the pump, and if the difference between the pressure in the system and the set point of the pump is greater than a preset threshold, the control system operates the motor on the ADO as necessary to reduce the difference so that it is within the threshold. Additionally, in some embodiments, when a new orifice is installed at the cutting head, the control system can direct the motor to initially adjust the setting of the ADO to an approximate position (e.g., a predetermined and/or theoretically-calculated position for new orifices) and then the control system “fine tunes” the ADO setting via the pressure feedback loop as the liquid jet cutting system comes up to pressure and begins operation. Embodiments of the motorized ADO control systems described herein can reduce the need for operator involvement, provide a reliable solution for controlling system pressures, and reduce overall component fatigue and wear due to pressure spikes/dips.
During setup and operation of the liquid jet cutting system, the ADO 100 will typically need frequent manual adjustment to maintain the pressure in the system at a desired level while the system is not cutting. The need for frequent adjustment can be caused by a number of different factors, including changes in size of the stem 112 resulting from thermal expansion and contraction in use, and from wear of the stem 112 over time. The change in size of the stem 112 can affect the flow of high-pressure liquid through the dump orifice 114 and the corresponding system pressure, requiring that the ADO 100 be manually adjusted to maintain the pressure at the desired level. Additionally, the ADO 100 will usually need readjustment when a new cutting nozzle orifice is installed, because of variability in dimensions between different orifices. If the position of the stem 112 is not adjusted as it expands, contracts and/or wears, or when a new orifice is installed, then pressure spikes and dips can occur when the cutting head nozzle switches between operational states (e.g., when transitioning between cuts). These pressure spikes/dips can have adverse effects on the liquid jet cutting system, including increased fatigue and premature wear of high-pressure components, and on the quality of the work product created by the liquid jet cutting system.
In practice, however, some operators may find that the hand knob 106 is difficult to access and/or that the ADO adjustment process is tedious. As a result, operators may fail to check and/or adjust the ADO 100 as often as necessary, resulting in spikes and dips in the system pressure during operation which, as noted above, can lead to increased fatigue and premature wear of the high-pressure system components. Additionally, at times the operator may turn the adjustment knob 106 in either too far or too hard, thereby causing the stem 112 to become stuck in its seat and cause a pressure spike during operation, and possibly requiring a subsequent rebuild or replacement of the ADO 100.
Certain details are set forth in the following description and in
The accompanying Figures depict embodiments of the present technology and are not intended to be limiting of its scope. The sizes of various depicted elements are not necessarily drawn to scale, and these various elements may be arbitrarily enlarged to improve legibility. Component details may be abstracted in the Figures to exclude details such as position of components and certain precise connections between such components when such details are unnecessary for a complete understanding of how to make and use the invention. Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments of the present technology. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the spirit or scope of the present disclosure. In addition, those of ordinary skill in the art will appreciate that further embodiments of the present technology can be practiced without several of the details described below. In the Figures, identical reference numbers identify identical, or at least generally similar, elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refers to the Figure in which that element is first introduced. For example, element 210 is first introduced and discussed with reference to
In the illustrated embodiment, the motorized ADO 220 includes a valve housing 210 that contains an adjustable dump orifice 214. The flow of high-pressure liquid through the dump orifice 214 is controlled by a dump orifice valve 221 that includes a tapered pin or “stem” 212. As described in greater detail below with reference to
In the illustrated embodiment, the liquid jet cutting system 200 further includes a controller 230 (shown schematically) operably connected to the pump 208, the motor 222, the first and second on/off valves 216a, b, and one or more pressure sensors 236. In some embodiments, the pressure sensor 236 can be a potentiometric pressure transducer configured to provide an electronic signal to the controller 230 that is indicative of the operating pressure of the liquid contained in the high-pressure conduit 206. In other embodiments, other types of pressure sensing devices known in the art can be used to provide pressure information to the controller 230, including other types of pressure transducers, piezoelectric pressure sensors, strain gauge pressure sensors, electromagnetic pressure sensors, optical pressure sensors, inductive pressure sensors, capacitive pressure sensors, variable reluctance pressure sensors, etc. Although, the pressure sensor 236 is illustrated as being operably connected to the high-pressure conduit 206 and in fluid communication therewith, in other embodiments the pressure sensor 236 and/or other pressure sensors can be mounted to the pump 208 (to, e.g., monitor the pressure at the pump 208), to the cutting head 202, and/or to other portions of the system 200 to monitor and/or determine the pressure of the working liquid and provide a corresponding signal or signals to the controller 230. Additionally, it will be appreciated that although a single pressure sensor 236 is illustrated in
The controller 230 can include one or more processors 232 and memory 234 that can be programmed with instructions (e.g., non-transitory computer-readable instructions contained on a computer-readable medium) that, when executed by the one or more processors 232, control operation of the motor 222 and/or other portions of the liquid jet cutting system 200. For example, in some embodiments, the controller 230 can be operably connected to the motor 222 and the pressure sensor 236 in a closed loop system in which the controller 230 receives feedback (e.g., liquid pressures) from the pressure sensor 236 during operation of the liquid jet cutting system 200, and then responds by adjusting the setting of the dump orifice valve 221 via the motor 222 as necessary to achieve a desired operating pressure. In some embodiments, the desired operating pressure can be the pressure set point of the pump 208 (i.e., the pressure that the operator sets the pump 208 to operate at). In such embodiments, the controller 230 can compare the liquid pressure in the system as indicated by the pressure sensor 236 to the pressure set point of the pump 208, and if the liquid pressure in the system differs from the pressure set point by more than a preset threshold amount (e.g. by more than +/−10 psi, +/−100 psi, +/−200 psi, etc.), the controller 230 responds by adjusting the setting of the dump orifice valve 221 via the motor 222 as necessary to bring the pressure within the threshold. After adjusting the dump orifice valve 221, the controller 230 again receives pressure feedback from the pressure sensor 236 and makes further adjustments to the dump orifice valve 221 if necessary. For example, in some embodiments, when the liquid jet cutting system 200 is cutting a workpiece 218, the pressure of the high-pressure liquid observed in, e.g., the high-pressure conduit 206 (and/or the cutting head 202 and/or the pump 208) should be between about 3,000 to about 5,000 psi higher than the pressure observed in the high-pressure conduit 206 when the cutting head 202 is closed and the motorized ADO 220 is open and dumping liquid, as would occur, for example, when the cutting head 202 is traversing towards the next cut of the workpiece 218. By use of embodiments of the closed loop feedback system described herein, the controller 230 can control the motor 222 as necessary to adjust the dump orifice valve 221 (e.g., a position of the stem 212 and thereby a size of open cross-sectional area through dump orifice valve 221) and maintain the desired operating pressures in the liquid jet cutting system 200 while avoiding detrimental spikes and dips in pressure.
Although some embodiments of the present technology monitor the liquid pressure in the system 200 and utilize the pressure as an input to the controller 230 for control of the motor 222, in other embodiments, the controller 230 can utilize the operating pressure of the pump 208 as feedback or an input for control of the motor 222. In yet other embodiments, rather than using a direct electrical signal from, e.g., the pressure sensor 236 and/or a pressure sensor on the pump 208 or the cutting head 202, the controller 230 can receive digital instructions via software for control of the motor 222. Such instructions can be generated by, e.g., the processor 232 (or another processor associated with the liquid jet cutting system 200) in response to a monitored pressure in the liquid jet cutting system 200. In some embodiments, the controller 230 can be a special purpose computer or data processor that is specifically programmed, configured, or constructed to perform one or more of the operations described in detail herein. While certain functions may be described herein as being performed exclusively by the controller 230, these functions can also be practiced in distributed environments where functions or modules are shared among separate processing devices.
Although certain components and features of the liquid jet cutting system 200 may be omitted from
In the illustrated embodiment, the adapter 226 includes a first end portion 328a and a second end portion 328b. The first end portion 328a is threadedly received in a correspondingly threaded bore 324 in the valve housing 210 and can carry one or more seals 326 to prevent high-pressure liquid from escaping the valve housing 210 around or through the adapter 226. The second end portion 328b of the adapter 226 is threadedly received in a corresponding threaded bore 330 in a first flange 322a of the coupling housing 224 to fixedly attach the coupling housing 224 to the valve housing 210. The coupling housing 224 further includes a second flange 322b that is fixedly attached to a corresponding flange 320 of the motor 222 by means of one or more fasteners 321 (e.g., 150241302.1 screws or bolts). In some embodiments, the coupling housing 224 can be made from aluminum. In other embodiments, the coupling housing 224 can be made from other suitable metallic and/or non-metallic materials.
Referring next to
In some embodiments, the coupling housing 224 can also contain a first alignment/spacer ring 316a and a second spacer ring 316b. The first alignment/spacer ring 316a is positioned in an annular groove in the motor flange 320 and is configured to concentrically align the motor 222 (or, more specifically, the motor output shaft 304) relative to the coupling housing 224 (or, more specifically, relative to the positioning element 308). In some embodiments, the first alignment/spacer ring 316a can also be used to prevent the coupling 300 from moving too far in the direction toward the motor 222 during use and, similarly, the second spacer ring 316b can be used as a hard stop to prevent the coupling 300 from moving too far in the direction toward the valve housing 210 and potentially sliding off of the first gear hub 303. In operation, rotational motion of the motor output shaft 304 is transmitted to the positioning element 308 via the first and second gear hubs 303 and 307, respectively, and the coupling 300. As described above, the corresponding rotation of the positioning element 308 in clockwise/counterclockwise directions advances/retracts the positioning element 308 through the bore 314 to move the stem 212 toward/away from the tapered seat 312 and thereby increase/decrease the pressure of high-pressure liquid flowing through the dump orifice 214.
Although, in the illustrated embodiment, the motor 222 produces torque which can selectively drive the output shaft 304 in both clockwise and counterclockwise rotation to adjust the setting of the stem 212, in other embodiments, other types of motors can be used for this purpose. For example, as noted above, in some embodiments a linear electric motor can be used that, instead of producing torque, provides a linear force that can drive, e.g., a corresponding output shaft in fore and aft translational (e.g., linear) motion. By way of example, in such embodiments the positioning element 308 may be an elongate shaft that, rather than rotate in the bore 314, is instead configured to slide fore and aft in the bore 314. Further, the linear output shaft of the motor can be coupled to the sliding positioning element so that linear movement of the output shaft toward the valve housing 210 drives the stem 212 toward the seat 312, while linear movement in the opposite direction moves the stem 212 away from the seat 312, thereby adjusting the flow through the dump orifice 214 and the corresponding system pressures as described above. Accordingly, it will be appreciated that the present technology is not limited to use with electric motors that provide rotational motion, but can also be used with a wide variety of other suitable drive devices (e.g., other types of electric motors) as disclosed herein. In some embodiments, one or more of the operable connections between components of the motorized ADO 220 may be non-threaded. In further embodiments (e.g., those using a linear electric motor), the motor can be directly attached to the valve housing 210 (e.g., without the coupling housing 224 or the adapter 226), and/or the motor output shaft can be directly coupled to the stem 212 (e.g., without the coupling 300).
Referring to
Returning to decision block 402, if the cutting head orifice has not been replaced, then the routine 400 can proceed directly to block 406 and start the pump 208. In some embodiments, starting the pump 208 can include the operator manually setting the pump to operate at a desired pressure (e.g., a pressure set point) using a suitable user interface. Once the pump 208 begins operating, it drives high-pressure liquid through the motorized ADO 220 via the high-pressure conduit 206 and the open valve 216b. In block 408, the controller 230 receives pressure feedback from the pressure sensor 236 which indicates, e.g., the operating pressure of the high-pressure liquid (e.g., water) in the system. As explained above, in other embodiments the controller 230 can receive the pressure feedback from a corresponding sensor at the pump 208, the cutting head 202, and/or another portion of the liquid jet cutting system 200. In decision block 410, based on the pressure feedback, the controller 230 determines if the operating pressure is within a specified range of a target pressure. As used herein, the term “target” pressure can refer to a desired operating pressure of the cutting system, (e.g., 30,000 psi, 40,000 psi, etc.) at a particular time. For example, in some embodiments, the target pressure can be the pressure set point of the pump 208. In other embodiments, such as when the cutting head 202 is transitioning between cuts (and/or the dump valve 221 is open), the target pressure may be less than the pressure set point of the pump 208 (e.g., between about 1,000 to about 6,000 psi less, or about 3,000 to about 5,000 psi less). In some embodiments, the specified range can refer to an acceptable range or preset threshold by which the pressure may vary from the target pressure and not require adjustment of the motorized ADO 220 (e.g., +/−10 psi, +/−100 psi, +/−200 psi, etc.). In other embodiments, the range may be omitted such that the controller 230 controls the setting of the motorized ADO 220 to achieve the target pressure based solely on a comparison of the system pressure to the target pressure.
If the operating pressure is not within a specified range of the target pressure, the routine proceeds to decision block 412 and the controller 230 determines if the operating pressure is greater than the specified range of the target pressure. If so, the routine proceeds to block 412 and the controller 230 sends a command to the motor 222 to automatically adjust the motorized ADO 220 to reduce the system pressure as described above. More specifically, with reference to
After either block 412 or 414, the routine proceeds to decision block 416 and the controller 230 awaits a signal or instruction (e.g., a software instruction) to start cutting a workpiece, such as the workpiece 218 shown in
Conversely, if at decision block 424 the controller 230 determines that the cutting operation has only been temporarily stopped while the cutting head 202 transitions between cuts, then the routine proceeds to block 426 and the controller 230 opens the ADO valve 216b while closing the cutting head valve 216a. This causes the flow of high-pressure liquid through the nozzle 204 to stop, while at the same time causing the high-pressure liquid to flow out of the liquid jet cutting system 200 via the motorized ADO 220 while the pump 208 continues to operate. In this way, the liquid jet cutting system 200 can maintain the high-pressure liquid at a desired pressure during a change of the cutting state and/or a transition of the cutting operation and avoid undesirable pressure spikes/dips as explained above. Moreover, to ensure that the operating pressure of the cutting system 200 is maintained within a desirable range, the routine can return to block 408 and the controller 230 again receives feedback from the pressure sensor 236 indicating the operating pressure of the cutting system 200. After receiving this input, the controller 230 proceeds through the subsequent steps of the routine as described above to automatically control the motorized ADO 220 and adjust the system operating pressure as necessary to maintain it within a specified range of a desired or “target” pressure. Once the cutting operation has been completed, the routine proceeds to block 428 and stops the pump 208, and the routine ends.
As described above in reference to
As those of ordinary skill in the art will appreciate, embodiments of the motorized ADOs described herein can reduce the need for operator involvement and provide a more reliable solution for controlling the pressure at the pump 208 (
Other advantages of embodiments of the systems, devices and methods described herein to control liquid jet cutting system pressures include: a reduction or elimination of operating pressure spikes and dips in the system; increased high-pressure component life; a reduction of part quality issues resulting from an incorrect ADO setting; a reduction in the level of user experience, skill, and training required; and/or a reduction of human involvement and a more automated operation.
Another advantage of the systems described herein is that, in some embodiments, the motor does not require an encoder or a similar device to set the ADO in an “initial” or “absolute” position, but instead the controller can use a simple “reset” algorithm to adjust the ADO in response to operating pressure feedback as described above.
References throughout the foregoing description to features, advantages, or similar language do not imply that all of the features and advantages that may be realized with the present technology should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present technology. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.
The above Detailed Description of examples and embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above. While specific examples for the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative implementations may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or sub-combinations. The teachings of the present disclosure provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. All of the patents and applications and other references identified herein, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the present disclosure can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the present disclosure.
In general, the terms used in the following claims should not be construed to limit the present disclosure to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the present disclosure encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the present disclosure.
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the various embodiments of the invention. Further, while various advantages associated with certain embodiments of the invention have been described above in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims. Moreover, although certain aspects of the invention are presented below in certain claim forms, the applicant contemplates the various aspects of the invention in any number of claim forms. Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms, in either this application or in a continuing application.
The present application claims priority to U.S. Provisional App. No. 62/952,013, titled MOTORIZED METHOD FOR CONTROLLING AN ADJUSTABLE DUMP ORIFICE ON A LIQUID JET CUTTING SYSTEM, which was filed on Dec. 20, 2019, and is incorporated herein by reference in its entirety.
Number | Date | Country | |
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62952013 | Dec 2019 | US |