This invention relates to component design and mounting arrangements for modular fluid flow control systems. In many industries, particularly the semiconductor manufacturing industry, critical fluids such as process gases must be transported within a facility without introducing contamination. These high purity systems involve a number of different flow control devices that are plumbed throughout a manufacturing site. Such systems can become unwieldy, making installation and modifications/repair costly and time consuming activities. In response to this problem, modular fluid flow control systems, sometimes referred to as “gas sticks”, are becoming more attractive as a design option. One exemplary system is described in pending published U.S. patent application Ser. No. 09/544,020 filed on Apr. 6, 2000 for MODULAR SURFACE MOUNT MANIFOLD ASSEMBLIES and published under publication no. US 2002/0000256 A1 on Jan. 3, 2002, the entire disclosure of which is fully incorporated herein by reference.
Modular designs typically include a series of down mount or surface mount components that are installed onto mounting plates, blocks or substrates, sometimes together called “sticks.” Various techniques may be used to establish fluid communication between the various surface mounted flow control devices. The sticks are then typically arranged lengthwise in a side by side manner and may be supported by bolting the sticks together or to additional support members. As a consequence, an assembler must install and tighten a number of bolts or other fasteners to securely install each stick to the support members. This makes assembly time consuming as it is important that all bolts be tightened to the proper torque. Additionally, bolt holes have to be provided for the sticks, and different system designs often have different hole patterns and lengths, making assembly of different components difficult or incompatible.
The substrates are often rectangular in shape, and when placed side by side with each other leave little or no room in between the substrates. The assembled substrates or sticks further are typically installed in a gas box or enclosure. Air is circulated through the box in order that minor leaks not contaminate the system. The closely spaced rectangular block design may represent a significant impediment to air flow within the gas box.
Because of the high fluid purity required, the fluid flow paths must oftentimes be purged. A purge cycle typically involves shutting off flow of the process fluid and then opening one or more purge valves that permit flow of a purge fluid through the flow path, for example, an inert gas. In modular systems, each flow control component is connected in fluid communication with a fluid flow path via a series of sealed ports at spaced component mounting locations. When a number of flow components are mounted on a substrate, it is common practice to make the mounting holes and port locations uniform in terms of spacing, size and location. This creates a problem for connecting a purge valve into the substrate because the purge valve requires an independent purge port that can be coupled to a purge line. Prior designs have attempted to solve this problem by running the purge flow path in a second substrate layer under the main substrate layer. However, the prior art purge valve typically requires three ports, one for inlet from the purge supply and two for connection with the passage, while the component mounting locations on the substrate have only two ports. The uniform port spacing and mounting holes on the substrate greatly restricts the ability to position or reposition a purge valve at specific locations on a substrate because the purge port extends through the same substrate structure as the main fluid flow path. Furthermore, the position of the purge port on a substrate may vary depending on the particular flow control device that is mounted to the substrate. Oftentimes then, a modification to the purge configuration involves a significant effort to rebuild the stick after a purge valve or purge line is installed or repositioned.
As illustrated in the referenced published disclosure, a typical surface mount substrate design includes two or more ports formed in the mounting surface of the substrate. These ports communicate with a fluid passageway associated with the substrate. The surface mounted components, such as valves, pressure regulators, mass flow controllers and so on have corresponding ports formed in the lower surface of the component base. The component base is bolted or otherwise attached to the substrate so that the ports in the component align with the ports in the substrate. In order to establish a fluid tight seal between the substrate and the surface mounted component, a metal C-seal is commonly used.
A conventional C-seal is an annular compressible seal that is partially received in a recessed cavity (counterbore) that surrounds the port in the substrate and the aligned port in the surface mounted component. When the two parts are joined together, the C-seal is compressed and forms a fluid tight seal that surrounds the ports and prevents leakage. C-seals may be installed using a suitable retainer device to ease assembly, again as described in the referenced publication.
The C-seal, when installed, engages a surface in the counterbore in the substrate and also engages a surface in the counterbore in the component that is being mounted on the substrate. These surfaces that the seal engages must meet specific hardness requirements, in order to obtain an effective metal to metal seal. For example, one user of such components requires a surface hardness of 102 Rockwell B Solution annealed. Stainless steel bar stock or plate does not have this hardness.
The invention contemplates a number of concepts for improving the manufacturability and ease of use of modular fluid components and assembly. In accordance with one aspect of the invention, a substrate design is provided to facilitate circulation air flow. In one embodiment, a substrate is provided that is sculpted or geometrically configured to eliminate non-structural portions of the substrate block material, thus providing gaps and openings to facilitate air flow between adjacent substrate rows.
In accordance with another aspect of the invention, a mounting arrangement is provided that simplifies assembly of a modular system. In one embodiment, the mounting arrangement includes a releasable mechanism for securing a substrate to a base member.
In accordance with another aspect of the invention, a configuration is provided that simplifies the initial assembly an/or replacement or re-positioning of a three port component, or other component that utilizes a fluid inlet that communicates with a second fluid passageway. In one embodiment, a purge valve is provided having an off-axis input port that is position independent of the substrate configuration.
In accordance with another aspect of the invention, components of a modular system are provided with work hardened seal surfaces. In one embodiment, a substrate and method of manufacture are contemplated for providing at least one seal surface that is work hardened so that the resulting seal surface is harder than the bulk material of the substrate.
Although the invention is described herein in the exemplary embodiment as being used with a modular gas stick such as having a substrate and surface mounted component, such description is intended to be exemplary in nature and should not be construed in a limiting sense. The invention may be used with any arrangement in which it is desired to establish a fluid tight seal between any two ports that communicate a fluid, be it liquid, gas, emulsion or a slurry for example, therebetween.
These and other aspects and advantages of the invention are fully described herein and will be readily understood in view of the accompanying drawings.
1. Introduction
The invention contemplates various improvements including component design and methods of manufacture for modular fluid flow systems. Although the invention is illustrated with exemplary embodiments, those skilled in the art will readily appreciate that the various aspects and advantages and concepts of the present invention can be realized in many different forms, configurations and embodiments. The invention, for example, is not limited to any specific down mount component design, nor any specific substrate design, material or seals. Moreover, various aspects of the invention are described herein and are embodied in the exemplary embodiments. These various aspects however may be realized in alternative embodiments either alone or in various combinations and sub-combinations thereof. Some of these alternative embodiments will be described herein but such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, arrangements, configurations, materials or form, fit and function. Those skilled in the art may readily adopt one or more of the aspects of the invention into additional embodiments within the scope of the present invention even if such embodiments are not expressly disclosed herein. Additionally, even though some aspects and features may be described herein as being a preferred and/or exemplary arrangement, method, configuration, form, fit, function, materials and so on, such description is not intended to suggest that such feature is required or necessary unless so expressly stated.
Each substrate 14 may support one or more flow components 12, and typically will be used for a specific gas or fluid, although the substrates need not carry different fluids. Each one of the substrates 14 includes at least one flow passage or path 18 (
Support members in the form of side rails 22 are provided to securely support the substrates 14. Two such side rails 22 are illustrated in
2. Substrate Profile
The particular substrate 14 that is illustrated in
The horizontal arm 30 of the T-shaped substrate 14 also includes a plurality of lateral lands or projections 50 that extend from the longitudinal central portion 34 of the substrate. The lands 50 have lower side surfaces 52 that extend perpendicular to the side surfaces 40 and 42 of the rib. Four bolt holes (for example) 54 are machined or otherwise formed in each set of lands 50. The lands 50 form or define component mounting portions 56 of the substrate 14 for mounting flow components 12 of the system 10. Each component mounting portion 56 includes a contiguous portion of the substrate 14 that includes four bolt holes 54 and two ports 20.
The substrate 14, in the area laterally outward of the central portion 34, need only have sufficient material in the areas of the bolt holes 54 to securely receive the bolts 16 (
When the substrate 14 is thus formed, the central portion 34 of the substrate 14 has parallel outer side surfaces 62 that are interrupted by the lands 50. The substrate 14 as a whole has an outer sculpted side surface 64. The outer side surface 64 comprises individual outer side surfaces 66 of the lands 50 that are disposed in a longitudinal array along lines 68 that extend parallel to the axis 36 and that are spaced transversely (laterally outward) from the central portion 34 of the substrate 14. The outer side surface 64 of the substrate 14 as a whole is interrupted by the passageways 60 to form the individual outer side surfaces 66 of the lands 50. The passageways 60 are bounded by the lands 50 and by the outer side surfaces 62 of the central portion 34 of the substrate 14.
When two or more substrates 14 are mounted adjacent each other on support members such as the side rails 22, the sculpted openings or passageways 60 provide substantial space through which air can be circulated. This can be important in closely enclosed fluid flow component systems 10 such as a gas box where it is necessary to provide adequate ventilation and when it is desirable, for space considerations, to mount two or more substrates 14 side by side or close together. Better air flow between components 12 means a lower volume of air that needs to be forced through the system 10, and also provides improved exhaust of any leaked gases. In addition, the openings 60 can provide space for parts that are not arranged along the linear extent of the substrates 14, for example, down mount components that can be placed between the substrates. Additionally, the sculpted substrate 14 has less mass than a comparable substrate that does not have the passageways 60. The lower mass can make the part easier to handle, and also less expensive to manufacture in terms of material costs.
Specifically,
The exact shape and geometry of the sculpted openings (passageways) 60 can be selected based on the particular air flow requirements and substrate design needed for a particular application. The embodiments illustrated herein are intended to be exemplary in nature and should not be construed in a limiting sense.
3. Releasable Mounting Arrangement
With reference to
In an exemplary form, the mounting arrangement 90 includes a base member, which in this case is provided by the side rail 22; a portion (the rib 38) of the substrate 14; and a securing arrangement 92 that secures the substrate 14 to the base. The securing arrangement 92 allows for easy assembly of the substrate 14 to the base and for easy removal of the substrate from the base.
In the exemplary embodiment, as described below, the securing arrangement 92 provides a clamping action between the substrate 14 and the side rail 22. The clamping action eliminates the need for threaded fasteners or other interconnections between the substrate 14 and the side rail 22. Thus, there is no hole pattern alignment required. Also, there is no relative length restriction between the length of the substrate 14 and the location of the side rail 22—that is, the substrate can be clamped to the side rail at any position along the length of the substrate. In cases where only two side rails 22 are used, a single substrate 14 may be removed from the system 10 by simply loosening two bolts, without removing them and allowing them to come free, as is described below.
The securing arrangement 92 (
The drive block 100 has a through hole 110 that extends vertically between the upper and lower surfaces 102 and 104 of the drive block. The through hole 110 is sized to accept a bolt 112 freely. The bolt 112 is threaded to cooperate with a tapped bolt hole 114 in the side rail 22.
The securing arrangement 92 also includes a driven block 120 that has parallel upper and lower surfaces 122 and 124. The height of the driven block 120, that is, the distance between its upper and lower surfaces 122 and 124, is slightly greater than the height of the rib 38 of the substrate 14.
The driven block 120 has opposite inner and outer side surfaces 126 and 128 that extend between the upper and lower surfaces 122 and 124. The outer side surface 128 is not perpendicular to the upper and lower side surfaces 122 and 124 but rather extends at an angle thereto. In the illustrated embodiment, the outer side surface 128 extends at an angle to the vertical that is the same as the angle of the inner side surface 106 of the wedge 100, that is, at 5 degrees off vertical. Thus, the outer side surface 128 of the driven block 120 is complementary to the inner side surface 106 of the wedge 100.
The inner side surface 126 of the driven block 120 extends generally perpendicular to the upper and lower surfaces 122 and 124 of the driven block. The corner of the driven block 120 may be cut away as at 130 for clearance. The width of the driven block 120, between the two side surfaces 126 and 128, is preferably a little greater than the width of one of the lands 50 on the substrate 14.
The driven block 120 has a through hole 132 that extends vertically between the upper and lower side surfaces 122 and 124 of the driven block. The through hole 132 is sized to accept a bolt 134 freely. The through hole 132 is slightly larger in diameter than the shank of the bolt 134. Alternatively, the through hole 132 may be oval or otherwise elongated in configuration in a direction along the length of the side rail 22, as shown in
The side rail 22 has two upstanding wall portions 140 and 142 that are spaced apart along the length of the side rail and that define a substrate mounting location on the side rail. The first wall portion 140 has an inner surface 144 that extends at an angle to the vertical that is preferably but not necessarily complementary to the angle of the outer side surface 108 of the wedge 100, that is, about 5 degrees from the vertical in the illustrated embodiment. The second wall portion 142 has an inner surface 146 that faces the angled surface 144 of the first wall portion 140 and that extends generally perpendicular to the horizontal to form a blocking portion of the side rail 22. The second wall portion 142 also has an upper side surface 148. A channel or groove 150 in the side rail 22 is defined between the two wall portions 140 and 142 and an upper side surface 152 of the side rail 22 and defines the aforementioned substrate mounting location on the side rail 22. The two bolt holes 114 and 136 in the side rail 22 are located between the first and second wall portions 140 and 142 and open into the channel 150.
The driven block 120 is located in the channel 150, on the upper surface 152 of the side rail 22. The bolt 134 extends through the through hole 132 in the driven block 120 and is threaded into the bolt hole 136 in the side rail 22. The head of the bolt 134 is recessed below the upper surface 122 of the driven block 120. The bolt 134 is tightened sufficiently to block vertical movement of the driven block 120 off the side rail, but is not tightened down completely. As a result, the driven block 120 is slidable along the side rail because of the oversize or elongate nature of the through hole 132 in the driven block.
The drive block 100 also is located in the channel 150, between the driven block 120 and the first wall portion 140. The bolt 112 extends through the through hole 110 in the drive block 100 and is threaded into the bolt hole 114 in the side rail 22. The bolt 112 is not tightened completely into the side rail 22. The head of the bolt 112 extends above the upper surface 102 of the drive block 100. Because the bolt 112 is not tightened completely, the drive block 100 is movable vertically relative to (toward and away from) the side rail 22.
The drive block 100 rests on the first wall portion 140 of the side rail 22 and on the driven block 120, at a location off the upper surface 152 of the side rail. Specifically, the angled outer side surface 108 of the drive block 100 is in abutting engagement with the angled inner side surface 144 on the first wall portion 140 of the side rail 22. The angled inner side surface 106 of the drive block 100 is in abutting engagement with the angled outer side surface 128 of the driven block 120.
To assemble the substrate 14 to the side rail 22, the substrate is placed in association with the side rail as shown in
The bolt 112 that extends through the drive block 100 is then screwed farther into the bolt hole 144 in the side rail 22. As a result, the bolt 112 moves axially, that is, in a downward direction as viewed in
The angled surfaces 106 and 108 of the drive block 100 cooperate with the angled surfaces 144 and 128 of the first wall portion 140 and of the driven block 120, respectfully, to exert laterally outwardly directed force on both the first wall portion and on the driven block. Because the first wall portion 140 of the side rail 22 is fixed in position while the driven block 120 is movable, this force causes the driven block to slide laterally along the side rail, in a direction to the right as viewed in
The lateral sliding movement of the driven block 120 causes the rib 38 of the substrate 14 to be captured and clamped between the driven block and the second wall portion 142 of the side rail 22. The angled threaded connection between the bolt 112 and the side rail 22 provides a significant mechanical advantage in producing this clamping force when the bolt 112 is rotated. In addition, the engagement of the angled surfaces of the drive block 100, the driven block 120, and the first wall portion 140 of the side rail 22, also provides a significant mechanical advantage in producing this clamping force when the bolt 112 is rotated. As a result, a relatively light rotational force on the drive bolt 112 produces sufficient clamping force on the substrate rib 38 to hold the substrate 14 and its associated components 12 securely in place on the side rail 22.
To release the substrate 14 from the side rail 22, the bolt 112 is loosened, that is, partially unthreaded from the side rail 22. When the bolt 112 is thus loosened, the clamping force on the rib 38 of the substrate 14 is reduced and the substrate can be removed from the side rail 22. This removal can be accomplished simply by lifting the substrate 14 straight up, as there are no mounting bolt holes or mounting bolts extending vertically through the substrate. It is not necessary to remove the bolt 112 completely from the side rail 22 or the drive block 100, but only to loosen it. Therefore, the drive bolt 112 remains captive on the side rail 22, and does not need to be fully backed out which might cause it to be misplaced. When a substrate 14 is thereafter to be assembled again to that particular substrate mounting location on the side rail 22, no loose parts must be found.
Only a single bolt 112 is required to be tightened and loosened to install and remove one end of the substrate 14. Thus, only two bolts 112 are needed to mount an entire substrate 14 at both ends. No bolt hole alignments are needed with the substrate 14. The driven block bolt 134 holds the driven block 120 to the side rail 22 when a substrate 14 is not installed at a particular location.
The clamping of the rib 38 of the substrate 14 also eliminates the need for threaded fasteners or other interconnections between the substrate and the side rail 22. Thus, there is no hole pattern alignment required. Further, there is no relative length restriction between the length of the substrate 14 and the location of the side rail 22—that is, the substrate can be clamped to the side rail at any position along the length of the substrate. In cases where only two side rails 22 are used, a single substrate 14 may be removed from the system 10 by simply loosening two bolts Other securing arrangements are usable. For example, a different portion of the substrate 14 might be clamped. The invention also can be used with a substrate 14 having other than a T-shaped configuration. For example, the invention is applicable to a system 10 in which the clamp engages the sides of a generally rectangular substrate 14. Thus, the securing assembly shown in the drawings is only illustrative of the invention.
4. Flow Components With Off-Axis Port
With reference again to
In accordance with one aspect of the invention, the purging arrangement 158 is designed such that purging fluid can be introduced into the primary or main fluid flow path 18 of a substrate 14 that supports the purge valve 160 without having to pass through a port 20 or conduit in the substrate. A purge valve requires a third port or fluid inlet, in addition to the two ports found in other components 12. As described below, the purge fluid inlet of the purge valve 160 is located off the axis 36 of the substrate 14, so that uniform inlet and outlet port locations 20 may be used at all component mounting locations 56 along the length of the substrate, and no specific portion of the substrate needs to be modified so as to be dedicated for use with a purge valve. As a result, a purge valve 160 may be positioned at any location along the length of the substrate 14 that is convenient for running the purge line. This design also facilitates installing or repositioning a purge valve 160 on a substrate 14 without having to rebuild or modify the basic substrate assembly.
The purge valve 160 includes a base or valve body 162. The purge valve base 162 includes a mounting flange 164 that has four fastener openings or bolt holes 166 at its four corners. The mounting flange 164 has a configuration that mimics the configuration of the mounting flanges of other components 12 to be mounted on the substrate 14. Thus, the purge valve 160 is adapted to fit exactly into any one of the series of identical component mounting locations 56 along the length of the substrate 14. The bolt holes 166 in the flange 164 are adapted to overlie the bolt holes 54 in the component mounting location 56 of the substrate 14. The flange 162 also includes two mounting holes 168 that receive bolts (not shown) for connecting the purge supply 161 to the flange 112.
The flange 162 includes a process fluid inlet port 170 and a process fluid outlet port 172. The spacing of the outlet and inlet ports 170 and 172 is preferably arranged to be uniform with that of other surface mounted components 12 of the system 10. Thus, the purge valve 160 can be mounted at any one of the plurality of component mounting locations 56 along the length of the substrate 14, and have its outlet and inlet ports 170 and 172 align with the ports 20 on the substrate 14 to enable fluid communication with the flow channel 18.
The inlet port 170 communicates with an inlet passage 174 in a pedestal 175 of the valve base 162. The outlet port 170 communicates with an outlet passage 176 in the pedestal 175 of the base 162. The inlet passage 175 and the outlet passage 176 are connected with each other within the valve base 162. As a result, the purge valve 160 enables free flow of fluid between the inlet port 170 and the outlet port 172 whenever the purge valve is mounted on the substrate 14.
The mounting flange 164 of the purge valve base 162 also includes a purge fluid inlet port 180. The purge inlet port 180 is connected by a purge fluid passage 182 with a valve chamber 184 in the valve body 162. The purge fluid passageway 182 extends at an angle outward from the pedestal 175 to the inlet port 180, as can be seen in
Preferably, but not necessarily, the purge fluid passage 182 is integral to the base 162. Due to the relative complexity of the base 162, it is contemplated that the base 162 be formed by a casting or molding process, rather than by machining, to reduce cost. However, any suitable process may be used as required. The base 162 in one embodiment may be made from aluminum or plastic, although other materials can be used.
An internal passage 186 in the base 162 connects the valve chamber 184 with the inlet and outlet passages 174 and 176. The internal passage 186 terminates in a purge outlet port 188 at the chamber 184. A valve seat 190 on the valve body 162 extends around the purge outlet port 188.
The purge valve 160 includes a movable valve member in the form of a flexible diaphragm 192. The diaphragm 192 is fixed at its outer periphery to the valve base 162. A central portion of the diaphragm 192 is located near the valve seat 190 and is movable relative to the valve seat when the valve 160 is opened and closed, as described below.
The purge valve 160 further includes a valve actuator 194 mounted on the valve body 162. The actuator 194 may be automatic or manual and may be pneumatic, hydraulic, etc. A nut 196 or other suitable arrangement may be used to join the valve actuator 194 to the valve body 162. The actuator 194 is operable to move a valve stem 198 to displace the diaphragm 192 so as to open and close the purge outlet port 188.
The exemplary purging arrangement 158 that is shown in the drawings includes the purge supply 161, which may be for example a fluid passageway provided by tubing 200 and a drop down fitting 202. The drop down fitting 202 is simply a fluid connection that establishes fluid communication between the purge line 200 and the purge inlet port 180 of the purge valve 160. An exemplary drop down fitting is shown in the above referenced patent application, although any suitable fitting or connection may be used. Preferably, although not necessarily, the drop down fitting 202 includes a purge supply support flange or base 204. The purge supply base 204 is configured to mate with and be connected with the base flange 162 of the purge valve 160. Preferably the connection between the purge supply base 204 and the purge valve base 162 is a releasable connection such as with threaded bolts (not shown), although other connection and coupling arrangements may be used as required. A suitable seal mechanism is provided between the purge supply base 110-204 and the purge valve base 162 to provide a fluid tight seal therebetween. In this manner, fluid communication is established between the purge supply line 200 and the purge inlet port 180 of the purge valve 160.
The base 162 of the purge valve may further include appropriate seal grooves 210 that surround the inlet and outlet ports 170 and 172, and align with corresponding seal grooves (not shown) in the substrate 14 to establish a fluid tight seal and communication between the valve 160 and the fluid passageways 18 in the substrate 14. A similar seal groove 212 surrounds the purge inlet port 180 and that corresponds to a seal groove in the purge supply base 204. The grooves 210 and 212 may receive a suitable compression seal 214 such as an o-ring, a C-seal or any other suitable seal device.
When the valve 160 is in a closed position, not shown, the actuator 194 causes the central portion of the diaphragm 192 to seal against the valve seat 190. As a result, fluid communication is blocked between the valve chamber 184 and the inlet and outlet ports 170 and 172. Thus, purge fluid from the purge supply 161 can not enter into the flow path 18 of the substrate 14 via the inlet or outlet ports 172 and 174 of the purge valve 160.
In order to admit purge fluid into the flow path 18 in the substrate 14, the purge valve 160 is actuated. The actuator 194 causes the central portion of the diaphragm 192 to come off the valve seat 190. As a result, the purge fluid passageway 192 in the purge valve 190 is placed in fluid communication, through the valve chamber 184, with the inlet and outlet ports 170 and 172 of the valve base 162. Purge fluid can flow from the purge conduit 200 through the fitting 202 into the purge valve 160 and thence into the fluid passage 18 in the substrate 14. When the purging process is completed, the valve 160 is again actuated to close the purge outlet port 188.
The purge system of the present invention is not dependent on the inlet and outlet porting arrangement of the valve base 162, nor on the mounting arrangement of the base to the substrate 14. Specifically, the fluid inlets and outlets 20 that are disposed along the substrate 14, are all disposed in a single linear array extending parallel to the axis 136 and to the length of the substrate 14. The purge inlet port 180 is not aligned with that linear array or axis 136. Instead, the purge inlet port 180 is spaced apart from the linear array of ports 20 in a direction generally normal to the length of the substrate 14. This results from the purge fluid passageway 182 extending at an angle outward from the pedestal 175, as can be seen in
The purge valve 160 can be located at any one of the plurality of identical component mounting locations 56 along the length of the substrate 14, because its third port (the purge port 180) is connected off the substrate. The purge valve base or flange 162 thus, in effect, decouples, or separates, the connection of the purge valve 160 with the purge supply 161 from the mounting arrangement of the purge valve 160 to the substrate 14. In addition, the purge supply passage 182 into the purge valve 160 does not pass through the pedestal 175, but rather only through the flange 162. In other words, the purge valve 160 is mounted on the substrate 14 using the same uniform inlet and outlet porting arrangements and mounting holes as any of the other fluid components 12 that are used in the system. Thus, a purge valve 160 may be positioned or repositioned on the substrate 14 without having to involve a rebuild of the substrate 14 itself. The purge supply 161 can then simply be plumbed in any convenient fashion or layout. For example, one purge valve 160 can be positioned on one substrate 14 at a different position from a purge valve 160 on an adjacent substrate 14, with fluid connections between them that do not extend through the substrates 14, in a manner similar to a jumper wire on a circuit board.
5. Hardened Seal Surfaces
In accordance with another aspect of the invention, seal surfaces of one or more components of a modular fluid system, such as the system 10, are work hardened. This aspect of the invention is described with reference to
The illustrated portion of the substrate 14 includes one of the ports 20 (
The port 20 on the substrate 14 also includes a recess 232, which in the illustrated embodiment is formed as a counterbore in the upper surface 226 of the substrate. The recess 232 is defined by a cylindrical, axially extending surface 234 and an annular, radially extending surface 236. The recess 232 extends around the bore 224. The radially extending surface 236 of the recess 232 forms a seal surface of the substrate 14.
The component 220 has a similar port and recess. Specifically, the illustrated portion of the component 220 includes a port 240. The port 240 includes a cylindrical surface 242 defining a bore or fluid passage 244 in the component 220. The bore 244 extends through an outer or lower surface 246 of the component 220. The bore 244 has a cylindrical configuration centered on the axis 230.
The port 240 also includes a recess 247, which in the illustrated embodiment is formed as a counterbore in the lower surface 246 of the component 220. The recess 247 is defined by a cylindrical, axially extending surface 248 and an annular, radially extending surface 250. The recess 247 extends around the bore 244. The radially extending surface 250 of the recess 247 forms a seal surface of the component 220.
When the component 220 is mounted on the substrate 14, the part 240 of the component is aligned with (coaxial with) the part 20 of the substrate 14. The seal surface 250 of the component 220 extends parallel to and is spaced apart from the seal surface 230 of the substrate 14. The two seal surfaces 236 and 250, along with the two cylindrical surfaces 234 and 248, define a seal cavity 252.
A C-seal or other suitable seal 254 is disposed in the seal cavity 252. The C-seal 254 is compressed axially between the seal surface 250 of the component 220 and the seal surface 236 of the substrate 14. The C-seal 254 seals between the component 220 and the substrate 14 so that fluid (gas) flowing between the bore 244 of the component and the bore 224 of the substrate does not leak out between the upper surface 226 of the substrate and the lower surface 246 of the component. The C-seal 254 is made from metal, and thus a metal to metal seal is effected between the C-seal and the seal surface 250 of the component 220. Similarly, a metal to metal seal is effected between the C-seal 254 and the seal surface 236 of the substrate 14.
In use of the system 10, the parts shown in
In known prior art modular systems, the components 220 and 14 are made of high quality and very hard wrought and machined stainless steel, such as alloy 316L. The components 220 and 14 are formed into substantially their final configuration, including the seal surfaces 250 and 236, by machining. The seal surfaces 250 and 236 are burnished, or polished, to a very high surface finish to provide an excellent seal surface for the C-seal 254, typically by electro-polishing or mechanical polishing. This type of mechanical polishing, or burnishing, effects a smoothing out of a surface, by taking material from higher areas and moving it into lower areas, to help minimize leak paths. For annular seal surfaces such as the seal surfaces 250 and 236, burnishing is typically done in a circumferential manner, that is, moving a tool in a circular pattern around the axis of the bore.
This aspect of the present invention is directed to reducing the cost of modular systems by, among other techniques, forming the first or second component or both by injection molding and sintering, or by casting, stainless steel such as alloy 316L, rather than by machining the components from wrought bar stock. Such a starting material can be significantly less expensive than wrought bar stock that is already hardened prior to machining. In addition, it can be substantially less expensive to cast or mold a part having the complex shape of the substrate 10.
However, sintered or cast stainless steel is not as hard a material as wrought stainless steel, and therefore it would be difficult to use a soft counterbore surface as a seal surface. In accordance with this aspect of the invention, then, a cast or molded stainless steel is work hardened so as to provide a sufficiently hard seal surface. Various different work hardening processes may be used, and in the exemplary embodiment herein the surfaces are work hardened by plastic deformation of the stainless steel alloy. Suitable work hardening techniques are known in the art;
In the example of
With the seal surfaces thus formed in accordance with the present invention, a high quality series of metal seals is formed for the system 10. Specifically, the seal between the seal surface 250 (
The metal flow caused by the tool is plastic deformation of the metal. As a result, the metal that is moved is hardened, so that the seal surface 264 (
The metal flow caused by the tool has two effects. First, it shapes the metal body to form the seal surface (the recess, or counterbore, may be formed either first or at the same time as the seal surface). Second, it effects work hardening of the material of which the seal surface is formed. These two effects occur simultaneously. Thus, the single step of deforming the metal with the tool both forms the seal surface and work hardens it.
It may be desirable to deform the metal on which the seal surface is being formed, more than once. For example, the material may be deformed radially outward first, as described above, then radially inward, and possibly one or more times additional outward or inward. Such additional plastic deformation of the material can help to increase further the hardness of the seal surface.
In some systems it may be desired to use a sealing device other than a C-seal. One known sealing technique is the use of a flat, annular metal gasket that is compressed between two sealing beads, such as described in U.S. Pat. No. 3,521,910. In accordance with another embodiment of the invention, a cast or molded and sintered stainless steel component is work hardened to have a suitable sealing bead so that a flat annular metal gasket may be used in lieu of a C-seal, for example as shown in
In
The work hardening of component 10 results from the plastic deformation of the stainless steel alloy (e.g., alloy 316L). Plastic deformation is obtained when stresses are applied that exceed the yield strength of the material. Work hardening of a metal can also be described as increasing the hardness of the metal by plastically deforming the metal below the recrystallization temperature range. In practice, steels are plastically deformed using processes such as cold heading, warm forming, forging, roll forming, bending, extruding, etc. Forming methods of particular interest to the disclosed principle of obtaining work hardened seal surfaces in molded and sintered, or cast, alloys are cold heading, warm forming, and roll forming.
As discussed above, it may be desirable to use a cast or molded stainless steel starting material, to form a component for use in the system 10. This can make the starting material less expensive. For example, metal injection molded (MIM) stainless steel 316 may have a hardness of about HRB (HRB refers to Rockwell Hardness B and HRC refers to Rockwell Hardness C as is well known in the art) in the low to high 60s. Cast and annealed material may have a hardness in the range of about HRB in the high 70s to low 90s. Strain hardened stainless steel 316 may have a hardness of about HRC 21-26.
A desirable hardness for the seal surface is a hardness of greater than about 300 Vickers or 30 HRC. Such a hardness is feasibly obtained by work hardening in accordance with the present invention.
The invention has been described with reference to the preferred embodiment. Modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims the benefit of U.S. provisional patent application Ser. Nos. 60/320,055, MOUNTING ARRANGEMENT FOR MODULAR FLUID COMPONENTS filed Mar. 26, 2003; 60/320,061, PURGE VALVE FOR MODULAR FLUID FLOW CONTROL filed Mar. 27, 2003; 60/320,062, WORK HARDENED SEAL SURFACE INTEGRAL WITH SUBSTRATE filed Mar. 27, 2003; and 60/320,063, MOUNTING BLOCK ARRANGEMENT FOR MODULAR FLUID filed Mar. 27, 2003, the entire disclosures all of which are fully incorporated herein by reference.
Number | Date | Country | |
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60320055 | Mar 2003 | US | |
60320061 | Mar 2003 | US | |
60320062 | Mar 2003 | US | |
60320063 | Mar 2003 | US |