Diaphragm valve with total valve cavity evacuation

A fluid valve incorporates a plunger with a fluid channel. The plunger is connected to a boss coupled to a diaphragm, this boss also includes a fluid channel and the plunger and boss fluid channels are in fluid communication. The boss fluid channel opens to the backside of the diaphragm in the valve cavity and permits substantially complete pressurization or evacuation of the volume behind the diaphragm in the valve. The substantially complete pressurization of the volume behind the diaphragm enables full closure of the diaphragm and improves contact of the diaphragm with the valve seat thereby improving performance of the valve.

TECHNICAL FIELD

This disclosure relates generally to fluid systems. More particularly, this disclosure relates to valves of fluid systems. Even more specifically, this disclosure relates to diaphragm valves and high precision diaphragm valves with full closure.

SUMMARY

There are many applications for which precise control over the amount or rate at which a fluid is dispensed or moved by a fluid system is necessary. In semiconductor processing, for example, it is important to control the amount and rate at which photochemicals, such as photoresist chemicals, are applied to a semiconductor wafer. The coatings applied to semiconductor wafers during processing typically require a flatness across the surface of the wafer that is measured in angstroms. The rates at which processing chemicals are applied to the wafer have to be controlled in order to ensure that the processing liquid is applied uniformly. Moreover, many photochemicals used in the semiconductor industry today are very expensive, frequently costing as much as $1000 a liter. Therefore, it is preferable to ensure that a minimum but adequate amount of chemical is used and that the chemical is not damaged by the pumping apparatus.

To achieve these goals, some designs for fluid systems for such chemicals rely on diaphragm valves to move or exert pressure on the process fluid. Hydraulic or pneumatic pressure is typically used to control pressure on one side of the diaphragm to cause the diaphragm of the valve to move, thereby opening or closing the valve and moving fluid through the system.

In particular, these diaphragm valves may utilize a diaphragm that is captured or otherwise retained around an outer edge in a valve cavity. Hydraulic or pneumatic pressure can then be applied to the back side of the diaphragm to open or close the diaphragm valve. Typically, however, the actuating pressure is applied to the back side of the diaphragm unevenly. In particular, the actuating pressure may be directly applied to the diaphragm only at a center portion of the diaphragm. Accordingly, the diaphragm is moved or held in a closed position by applying sufficient actuating pressure to this center portion of the diaphragm, forcing fluid from the valve cavity and closing off the fluid flow path.

These types of diaphragm valves have a number of problems. One of the main issues is that it may be difficult to obtain full closure of these types of diaphragm valves. More specifically, in a closed position the diaphragm of the valve should fully seat against a valve seat of the valve cavity. Achieving this full seating is difficult, however, because in such valve designs the actuating pressure is directly applied only to the center of the diaphragm, while the diaphragm is retained around the outer periphery. As a result, the diaphragm may not fully seat against the valve seat and may bulge away from the valve seat in one or more areas between the center portion of the diaphragm (where the actuating pressure is being directly applied) and the retained outer periphery of the diaphragm. These bulges may trap air or process fluid, causing the formation of air bubbles or gels. The air bubbles or gels may cause a number of problems to occur, including increasing the priming time of a pump incorporating such valves, promoting particle generation, mis-dispense of fluid from fluid systems incorporating such valves, difficulty in cleaning fluid systems incorporating these valves, poor fluid handling characteristics of fluid systems, or other deleterious effects. The problems endemic to these types of valves may be further exacerbated by the high-viscosity fluids used in some semiconductor processes.

SUMMARY

What is desired are diaphragm valves that obtain full closure by allowing the diaphragm of the valve to fully seat. It will be understood with respect to this disclosure that the use of the terms full closure and full seating are meant to indicate closure or seating that achieves greater evacuation of air or fluid from between a diaphragm and a valve seat than previous designs of diaphragm valves lacking the advantageous features of embodiments of the present disclosure.

To those ends, among others, diaphragm valves as disclosed may achieve full closure by allowing actuating pressure to be more evenly or fully applied to the back side of one or more portions of the diaphragm. Specifically, certain embodiments of diaphragm valves as disclosed may have a fluid passage formed in a portion of the diaphragm assembly, allowing fluid communication between the back side of the diaphragm and a pressure source (e.g., a source of the pressurized actuating fluid). Even more particularly, in certain embodiments, the fluid flow passage formed in the diaphragm assembly allows the actuating fluid to flow to the portion of the valve cavity behind the diaphragm between the center portion of the diaphragm and a retained outer edge of the diaphragm. The actuating fluid can therefore exert pressure directly on the back side of the diaphragm, forcing the diaphragm to fully seat against the valve seat and thus fully close the valve.

Moreover, in embodiments of a diaphragm valve that utilize an actuator (e.g., a plunger or the like) acting on the diaphragm to open or close the diaphragm, a fluid passage may also be formed in the actuator to allow fluid communication between the pressure source and the back side of the diaphragm. In these embodiments, pressurized actuating fluid can flow from the pressure source through the fluid passage formed in the actuator, through the fluid passage formed in the diaphragm assembly to the portion of the valve cavity behind the diaphragm between the center portion of the diaphragm and the retained outer edge of the diaphragm, forcing the diaphragm to fully seat against the valve chamber and fully close the valve.

One embodiment of a valve comprises a plunger in a valve assembly cavity, the plunger includes a plunger cavity formed in a plunger stem, and a plunger fluid flow passage is formed in the plunger. The plunger fluid flow passage fluidly connects an actuation fluid cavity in a valve plate and the plunger cavity. The valve further includes a diaphragm assembly in the valve assembly cavity, the diaphragm assembly comprises a diaphragm and a boss. The diaphragm assembly is secured in the valve between a diaphragm spacer and a fluid block in the valve assembly cavity and the diaphragm assembly fluidly separates the valve cavity in the valve assembly into a process fluid side and an actuation fluid side. In the valve, the boss is coupled to the plunger stem through a passage of the diaphragm spacer. The boss comprises a boss fluid flow passage formed through it that fluidly interconnects the activation fluid cavity, the plunger cavity, and the actuation fluid side of said valve cavity.

In some embodiments of the valve, the plunger fluid flow passage and boss fluid flow passage have a length and cross section such that the plunger is translated toward or away from the fluid actuation cavity in the valve plate by a change in pressure in the fluid activation cavity before substantial pressure is applied to or reduced in the volume of the fluid actuation side of the valve cavity between the back of the diaphragm and the diaphragm spacer.

In some embodiments of the valve, the plunger fluid flow passage open to the plunger cavity and an opening of the boss fluid flow passage that opens to a back side of diaphragm and the activation fluid side of valve cavity, allows fluid communication between plunger cavity and valve cavity when opening of boss fluid flow passage clears central passage of diaphragm spacer.

Accordingly, embodiments as disclosed provide a number of advantages. For example, embodiments may achieve full closure of a valve and may evacuate a great deal more fluid (e.g., either process fluid or air) from the valve when closed. In some embodiments, around 40% more fluid or air may be evacuated from a closed embodiment of such a valve than a comparable valve without such fluid passages formed in the diaphragm. The full closure of embodiments of valves of this type may reduce priming time for pumping or dispense systems employing these valves and decrease the formation of gels from residual process fluid. Consequently, the use of embodiments of such valves may result in more desirable fluid flow or dispense characteristics generally, reduced particle generation, and allow easier cleaning of such valves or fluid systems employing such valves.

DETAILED DESCRIPTION

Certain diaphragm valves may utilize a diaphragm that is captured or otherwise retained around an outer edge in a valve cavity, with hydraulic or pneumatic pressure (an actuation fluid) being applied through an actuating plunger to a back side of the diaphragm to open or close the diaphragm valve. It is the case, however, that in certain of these valves the actuating pressure may be applied to the back side of the diaphragm unevenly or incompletely, preventing full closure of the valve and resulting in process fluid trapped between the diaphragm and valve seat.

FIG. 1is a diagrammatic representation of a cross-section of just such a prior art valve. Here, valve100includes valve assembly102disposed in assembly cavity110formed between valve plate150and fluid block140. Fluid block140includes inlet fluid flow passage142and outlet fluid flow passage144open to assembly cavity110through valve seat face112of fluid block140. Inlet fluid flow passage142may be coupled to a source of fluid (e.g., process fluid or the like) such as by a pump, container or the like (not shown). Valve assembly102is disposed in assembly cavity110and includes a diaphragm120, diaphragm spacer130and plunger160. Diaphragm spacer130is disposed between the diaphragm120in assembly cavity110proximate to the fluid block140, and plunger160disposed in assembly cavity110distal from the fluid block140and proximate the valve plate150.

Valve cavity170is formed from the portion of the assembly cavity110between the diaphragm spacer130and valve seat112of fluid block140. In particular, circumferential channel142may be formed in fluid block140at the circumference of valve seat face112. This circumferential channel142is configured to capture lip122of diaphragm120and retain the diaphragm120in cooperation with shoulder132of diaphragm spacer130when sufficient coupling force is applied to the valve plate150. The diaphragm120separates the valve cavity into a process fluid side and a non-process fluid side. Specifically, valve assembly102may be disposed in assembly cavity110and valve plate150coupled to the fluid block140using fasteners such as screws or the like (not shown). The coupling force (e.g., torque on the screws) may cause shoulder152of valve plate150to exert force on corresponding shoulder134of diaphragm spacer130. Shoulder132of diaphragm spacer in turn, exerts force on lip122of diaphragm120captured in channel142of fluid block140to retain diaphragm120in channel142.

Diaphragm120includes boss124coupled to plunger160. In particular, diaphragm spacer130may be annular and plunger160is coupled to the diaphragm120through central passage of annular diaphragm spacer130. Specifically, stem162of plunger160may extend through the central passage of diaphragm spacer130and be coupled to boss124of diaphragm120. This coupling may be accomplished via cooperating threads on boss124and plunger stem162. As another example, plunger stem162may be annular and include a lip disposed at the end of the plunger stem162distal from the plunger body. This lip may cooperate with a shoulder formed at the base of boss124of the diaphragm120by a circumferential channel at the base of diaphragm boss124where boss124joins diaphragm120. An O-ring (not shown) may be disposed in an annular channel in diaphragm spacer130and seal against the outer wall of stem162disposed in the central passage of diaphragm spacer130.

Pneumatic cavity180is formed from the portion of assembly cavity110between the back side of plunger160(e.g., the face of plunger distal from the fluid block140) and valve plate150. Pneumatic cavity180is in fluid communication with a pressure source through fluid flow passage154formed in valve plate150. Fitting190may serve to couple the pressure source to the fluid flow passage154. An O-ring164may be disposed in an annular channel169in plunger160and seal against the inner walls of assembly cavity110in valve plate150to seal pneumatic cavity180from other portions of the assembly cavity110. It should be noted here that while certain descriptions, example and embodiments presented herein are described with respect to pneumatics and pneumatic pressure such descriptions, examples and embodiments could equally well be applied to, or utilized with, hydraulics or hydraulic pressure, in general the application or removal (reduced pressure) of an actuation fluid, as those of ordinary skill will understand.

In operation, to open the valve100the fluid flow passage154is exposed to force (e.g., by an application of vacuum or reduced pressure through fitting190from a pressure source). As a result of the application of vacuum or reduced pressure, force is applied to the back side of plunger160in pneumatic cavity180, drawing plunger160in a direction away from fluid block140(and toward valve plate150). As plunger160is drawn away from fluid block140, plunger stem162draws diaphragm boss124through the central opening of diaphragm spacer130in turn drawing diaphragm120in a direction away from valve seat112of fluid block140and opening the valve100.

Fluid (e.g., a process fluid or the like) may then be introduced into valve cavity170from inlet fluid flow path172. The drawing of the diaphragm120away from the valve seat112may serve to draw fluid into valve cavity170through the inlet fluid flow path172, the fluid may be placed under pressure (e.g., by a pump or the like coupled to the inlet fluid flow path172) to force fluid through inlet fluid flow path172into the valve cavity170, or some combination of the two may serve to introduce fluid into the valve cavity170.

When it is desired to close valve100and force fluid through the outlet fluid flow path144, positive pressure may be applied to the plunger160from a pressure source through the fluid path154(e.g., by an application of pressurized actuating fluid such as air or gas through fitting190from the pressure source). In one embodiment, this pressure may be around 60 pounds per square inch (PSI). The application of the positive pressure to the plunger160in pneumatic cavity180drives the plunger160towards the fluid block140. As plunger160is driven toward fluid block140, plunger stem162drives diaphragm boss124through the central opening of diaphragm spacer130in turn forcing diaphragm120against valve seat112of fluid block140forcing the fluid in valve cavity170through the outlet fluid flow path144and closing the valve100. Pressure can be maintained in pneumatic cavity180by continuing to apply positive pressure to the actuating fluid from the pressure source through the fluid path154, maintaining valve100in a closed position by forcing diaphragm120against valve seat112.

As discussed above, however, the positive pressure to close the valve100is applied directly (e.g., via the plunger160driven by the pressurized actuating fluid) only to boss124at the center of diaphragm120. As a result, when the diaphragm120is moving from an open to a closed position, or is in a closed position, there is an annular space in valve cavity170behind the diaphragm120between the boss124and the lip122of diaphragm120retained in channel142where no pressure is directly applied to the diaphragm120to force the diaphragm120against valve seat112. As a result, in a closed position the diaphragm120may not fully seat against the valve seat112and may bulge away from the valve seat112in one or more areas of the annular portion of the diaphragm120between the boss124of the diaphragm (where the actuating pressure is being directly applied) and the retained lip122of the diaphragm. These bulges may trap air or process fluid, causing the formation of air bubbles, gels or particles. The air bubbles, gels or particles may cause a number of problems to occur, including increasing the priming time of a pump incorporating such valves, mis-dispense of fluid from a fluid system incorporating the valve, difficulty in cleaning fluid systems incorporating these valves, poor fluid handling characteristics, or other deleterious effects.

Accordingly, it is desirable to obtain full closure of these types of valves by better seating the diaphragm against the valve seat of the valve cavity. To those ends, among others, diaphragm valves as disclosed may apply actuating pressure more evenly or fully to the back side of the diaphragm of a valve. Specifically, certain embodiments of diaphragm valves as disclosed may have a fluid passage formed in a boss of a diaphragm assembly to allow fluid communication between a pressure source and a portion of the valve cavity behind a diaphragm. Even more particularly, in certain embodiments, the fluid flow passage formed in the boss allows the actuating fluid from the pressure source to flow to the portion of the valve cavity behind the diaphragm between a center portion (e.g., where the boss joins the diaphragm assembly) of the diaphragm and a retained outer edge of the diaphragm. The pressurized actuating fluid can therefore exert pressure directly on the back side of the diaphragm, forcing the diaphragm to fully seat against the valve seat and thus fully close the valve.

Moreover, in embodiments of a valve that utilize an actuator to exert force on a diaphragm, such as a plunger or the like, a fluid passage may also be formed in the actuator to allow fluid communication between the pressure source and the back side of the diaphragm. In these embodiments, pressurized actuating fluid can flow from the pressure source through the fluid passage formed in the actuator and through the fluid passage formed in the diaphragm to the portion of the valve cavity behind the diaphragm between the center portion of the diaphragm and the retained outer edge of the diaphragm, forcing the diaphragm to fully seat against the valve chamber or valve seat and fully close the valve.

It should be noted that in embodiments of such a valve, the same features that aid in closing of the valve through more full and even application of positively pressurized actuating fluid to the diaphragm may also allow more full and even application of actuating force applied (e.g., through the application of vacuum or reduced pressure) to open the valve by drawing the diaphragm in a direction away from the valve seat and open the valve.

Turning then toFIG. 2, a cross-section of one embodiment of a fully closing diaphragm valve is depicted. In this embodiment, valve200includes valve assembly202disposed in assembly cavity210formed between valve plate250and fluid block240. Fluid block240and valve plate250can be a unitary block of polytetrafluoroethylene (PTFE), modified PTFE, machined aluminum or other material. Because these materials do not react with or are minimally reactive with many process fluids, the use of these materials may allow flow passages and cavities to be machined directly into fluid block240with a minimum of additional hardware. Specifically, fluid block240may include inlet fluid flow passage (not shown) and outlet fluid flow passage244open to assembly cavity210through valve seat212of fluid block240. The inlet fluid flow passage may be coupled to a source of fluid such as a pump, container or the like.

Valve assembly202is disposed in assembly cavity210and includes a diaphragm assembly219having diaphragm220coupled to boss224, diaphragm spacer230and plunger260. Diaphragm assembly219may be a formed of a single piece of material or may be formed from a two (or more) pieces that are joined by, for example an adhesive or other fastener. The diaphragm assembly219, or portions thereof, can be made by machining, molding or another process.

Diaphragm spacer230is disposed between diaphragm220in assembly cavity210proximate to the fluid block240and plunger260disposed in assembly cavity210distal from the fluid block240and proximate the valve plate250. Valve cavity270is formed from the portion of the assembly cavity210between the diaphragm spacer230and valve seat face212of fluid block240. In particular, circumferential channel242may be formed in fluid block240at the circumference of valve seat face212. This circumferential channel242is configured to capture lip222of diaphragm220and retain the diaphragm assembly219in cooperation with shoulder232of diaphragm spacer230when sufficient coupling force is applied to the valve plate250. Specifically, valve assembly202may be disposed in assembly cavity210and valve plate250coupled to the fluid block240using fasteners such as screws or the like (not shown). The coupling force (e.g., torque on the screws) may cause shoulder252of valve plate250to exert force on corresponding shoulder234of diaphragm spacer230. Shoulder232of diaphragm spacer in turn, exerts force on lip222of diaphragm220captured in channel242of fluid block240to retain lip222of diaphragm220in channel242.

Boss224of diaphragm assembly219is coupled to plunger260. In particular, diaphragm spacer230may be annular and plunger260coupled to the diaphragm assembly219through the central passage of annular diaphragm spacer230. Specifically, stem262of plunger260may extend through the central passage of diaphragm spacer230and be coupled to boss224of diaphragm assembly219. This coupling may be accomplished via threaded joint225formed from cooperating threads on boss224and plunger stem262(e.g., threads on exterior surface of boss224and an interior wall of an annular plunger stem262). As another example, plunger stem262may be annular (e.g., a hollow cylinder) and include a lip disposed at the end of the plunger stem262distal from the plunger body. This lip may cooperate with a shoulder formed at the base of boss224of the diaphragm assembly219by a circumferential channel at the base of diaphragm boss224where boss224joins diaphragm220. An O-ring236may be disposed in annular channel238in diaphragm spacer230and seal against the outer wall of stem262disposed in the central passage of diaphragm spacer230.

Pneumatic cavity280is formed from the portion of assembly cavity210between the back side of plunger260(e.g., the face of plunger distal from the fluid block240) and valve plate250. Pneumatic cavity280is in fluid communication with a pressure source through fluid flow passage254formed in valve plate250. Fitting290may serve to couple the pressure source to the fluid flow passage254. An O-ring264may be disposed in an annular channel269in plunger260and seal against the inner walls of assembly cavity210in valve plate250to seal plunger260against walls of valve plate250.

Fluid flow passage266can be sized so that plunger260is translated toward or away from valve plate250in the pneumatic cavity before substantial pressure is applied to or reduced in the volume between the back of the diaphragm220and diaphragm spacer230.

Additionally, plunger260includes fluid flow passage266allowing fluid communication between plunger cavity268formed in the plunger stem262and pneumatic cavity280. Boss224of diaphragm assembly219also includes fluid flow passage226formed therethrough, having one opening to plunger cavity268and one opening228on the back side of diaphragm220to allow fluid communication between plunger cavity268and valve cavity270(e.g., when opening228of fluid flow passage226in boss224clears central passage of diaphragm spacer230). Fluid flow passage226may, in one embodiment, have two portions, a first portion formed along an axis aligned with the direction of travel of plunger260and boss224and a second portion formed along an axis perpendicular to this axis of travel. It will be noted however, that fluid flow passage226(and fluid flow passage266) may take almost any form or shape desired to achieve fluid communication between a source of (actuating) fluid pressure through fluid flow passage254and valve cavity270behind diaphragm220. For example, fluid flow passage226may have multiple openings to plunger cavity268or valve cavity270, or may be comprised of multiple distinct flow passages. Other embodiments are possible and are fully contemplated herein.

In operation, to open the valve200the fluid flow passage254is exposed to vacuum or reduced pressure (e.g., by an application of vacuum or lower pressure through fitting290from a pressure source). As a result of the application of vacuum or reduced pressure, force is applied to the back side of plunger260in pneumatic cavity280, drawing plunger260in a direction away from fluid block240. As plunger260travels away from fluid block240, plunger stem262draws diaphragm boss224through the central opening of diaphragm spacer230in turn drawing diaphragm220in a direction away from valve seat212of fluid block240and opening the valve200. Additionally, the force applied by an application of vacuum or reduced pressure through fluid flow passage254may be applied directly to the back side of diaphragm220in the region of valve cavity270behind the diaphragm220to open the valve200, as fluid flow passage266and plunger cavity268in plunger260and fluid flow passage226through boss224of diaphragm assembly219cooperate to allow fluid communication between fluid flow passage254and the annular space of valve cavity270behind diaphragm220. In one embodiment, the size of the components of the valve200may be configured such that when back side of plunger260reaches the wall of assembly cavity210in valve plate250distal from the fluid block240the back side of diaphragm220may contact face239of diaphragm spacer230, thereby reducing or eliminating the actuation fluid volume portion of the valve cavity270forming valve cavity270while maximizing the process fluid volume portion of the valve cavity270. The actuation fluid volume portion of the valve cavity270and process fluid volume portion of the valve cavity270are separated by the diaphragm220.

Fluid (e.g., a process fluid or the like) may then be introduced into valve cavity270from an inlet fluid flow path (not shown). The traveling of the diaphragm220away from the valve seat212may serve to draw fluid into valve cavity270through the inlet fluid flow path, the fluid may be placed under pressure (e.g., by a pump or the like coupled to the inlet fluid flow path) to force fluid through the inlet fluid flow path into the valve cavity270, or some combination of the two may serve to introduce fluid into the valve cavity270.

The valve assembly219fluidly separates the valve cavity270in the valve assembly210into a process fluid side and an actuation fluid side (volume between the backside of diaphragm220and diaphragm spacer230surface239. When it is desired to close valve200and force fluid through the outlet fluid flow path244, positive pressure may be applied to the plunger260from a pressure source through the fluid path254(e.g., by an application of pressurized actuating fluid such as air or gas through fitting290from the pressure source). In one embodiment, this pressure may be around 60 pounds per square inch (PSI). The application of the positive pressure to the plunger260in pneumatic cavity280drives the plunger260towards the fluid block240. As plunger260travels toward fluid block240, plunger stem262drives diaphragm boss224through the central opening of diaphragm spacer230in turn forcing diaphragm220against valve seat212of fluid block240, forcing the fluid in valve cavity270through the outlet fluid flow path244and closing the valve200by sealing the inlet fluid flow path and the outlet fluid flow path244.

Additionally, as plunger260moves toward fluid block240opening228of fluid flow passage226in boss224clears the central passage of diaphragm spacer230bringing the region of valve cavity270behind diaphragm220, or the actuation fluid side, into fluid communication with the pressure source through fluid flow passage226in boss224, plunger cavity268, fluid flow passage266in plunger260and fluid flow passage254. Accordingly, the pressurized actuating fluid from the pressure source is applied directly to the back side of the diaphragm220in the region of valve cavity270between boss224and the retained lip222of the diaphragm220. In other words, the pressurized actuating fluid from the pressure source is occupies the actuation fluid side volume between the backside of diaphragm220and the diaphragm spacer230surface239. The directly applied pressure may aid in closing the valve200and serves to achieve full closure of the valve200by forcing diaphragm220to fully seat against valve seat212, substantially eliminating air or process fluid trapped between diaphragm220and valve seat212. Pressure can be maintained against the plunger260and directly against the back side of the diaphragm220in valve cavity270by continuing to apply positive pressure to the actuating fluid from the pressure source through the fluid path254, maintaining valve200in a closed position by forcing diaphragm220against valve seat212.

In certain embodiments, flow passage226in boss224, fluid flow passage266in plunger260, or plunger cavity268in plunger260, may be sized so as to reduce stress on diaphragm220, boss224, or threaded joint225coupling boss224and plunger stem262, when opening or closing valve200. As discussed above, positive pressure may be applied to the plunger260from a pressure source through the fluid path254, causing plunger stem262to exert force on diaphragm boss224. Additionally, fluid flow passage226allows positive pressure from the pressure source to be applied directly to the back side of the diaphragm220. Since diaphragm220is coupled to plunger stem262by threaded joint225it is, however, highly desirable that the threaded joint225not be (overly or repeatedly) stressed.

It is thus desirable that when the valve200is actuated the center of the diaphragm220(e.g., where it joins boss224) moves (e.g., toward valve seat212to close the valve) before other portions of the diaphragm220. If the fluid passage266or plunger cavity268in plunger260are too large, however, then the other portions of diaphragm220will move before the center portion of the diaphragm220, stressing the threaded joint225. Repeated stressing of the threaded joint225may cause the joint225to separate or break. Accordingly, the fluid flow passage266or plunger cavity268may be sized (e.g., with respect to the diameter of plunger260, stem262, fluid passage226, size of boss224, etc.) to ensure that force is first applied to boss224, and thus center of diaphragm220, before it is applied to any other portion of diaphragm220(e.g., through fluid flow passage226). Furthermore, the ratio of the size of fluid flow fluid passage266or plunger cavity268with respect to the diameter of plunger260may be selected to insure that threaded joint225is not under tension (and may be substantially under compression).

It should be understood that while embodiments depicted herein have been described with respect to circular or annular diaphragms, valve seats, plungers, cavities, regions or features and the like, embodiments as disclosed herein that allow fluid communication between a region of a valve cavity behind a diaphragm and a source of actuating fluid may be equally effectively utilized with valves that have components or features of other shapes, including components or features that are oblong or rectangular. Such oblong or rectangular features may include diaphragms or bosses, diaphragm spacers or central regions of diaphragm spacers, valve seats, plungers or plunger stems, (assembly, pneumatic or valve) cavities, among other possible oblong or rectangular features or components.

FIGS. 3A-6depict an embodiment of a valve assembly and its components. Referring first toFIGS. 3A-3B,FIG. 3Ais an exploded view of one embodiment of valve assembly302, including diaphragm assembly319having diaphragm320, diaphragm lip322, diaphragm spacer330, O-ring336, O-ring364and plunger360. In one embodiment diaphragm assembly319may be PTFE or modified PTFE such as that sold by Daikin under the trademark Polyflon™, diaphragm spacer330and plunger360may be an polyoxymethylene (acetal) copolymer and O-rings336and364may be a fluoroelastomer or synthetic rubber such as that sold by DuPont under the trademark Viton®. It will be noted that these materials are given by way of example and that other, or different materials may be utilized based on the type, application or design of the valve assembly, or components or features thereof. These other materials may include, for example, polymers, including plastics, nylons, ethylene vinyl alcohol (EVOH), polyolefins, or other natural or synthetic polymers, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), poly(butylene 2,6-naphthalate) (PBN), polyethylene (PE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (HDPE), high-density polyethylene (HDPE), polypropylene (PP), and/or fluoropolymers, such as but not limited to, polychlorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), or ethylene tetrafluoroethylene (ETFE) including those sold by DuPont under the trademark Tefzel®.

Moving now toFIGS. 4A-4C, different views and details of one embodiment of diaphragm assembly319, including diaphragm320, diaphragm lip322, boss324, flow passage326, and flow passage328outlet are illustrated, including representative dimensions thereof.FIGS. 5A-5Billustrate different views and details of one embodiment of valve spacer330including o-ring annular channel338and face339of diaphragm spacer330which together with valve seat form valve cavity.FIG. 6illustrates representative dimensions of a view and details of one embodiment of plunger360, including plunger stem362, plunger cavity368, plunger fluid flow passage366and annular channel369in plunger360for a sealing o-ring. It will be noted that to the extent dimensions are provided in these figures, they are provided by way of example for particular embodiments or implementations and are not provided by way of limitation.

FIG. 7illustrates a valve700comprising a plunger760in a valve assembly cavity710, the plunger includes a plunger cavity768formed in the plunger stem762, a plunger fluid flow passage766through the plunger. The plunger fluid flow passage766fluidly connects the actuation fluid cavity780in the valve plate750and the plunger cavity768. The valve700has a diaphragm assembly719in the valve assembly cavity710, and the diaphragm assembly719has a diaphragm720and a boss724. In some embodiments of the diaphragm assembly the diaphragm is coupled to the boss. In the valve, the diaphragm assembly719can be secured between a diaphragm spacer730and a fluid block740in the valve assembly cavity710. The valve assembly702719fluidly separates the valve cavity770in the valve assembly702710into a process fluid side and an actuation fluid side (volume between the backside of diaphragm720and diaphragm spacer730surface739). Specifically, valve assembly702may be disposed in assembly cavity710and valve plate750coupled to fluid block740using fasteners such as screws or the like (not shown). The coupling force (e.g., torque on the screws) may cause shoulder752of valve plate750to exert force on corresponding shoulder734of diaphragm spacer730. Shoulder732of diaphragm spacer in turn, exerts force on lip722of diaphragm720captured in channel742of fluid block740to retain diaphragm720in channel742. The boss724is coupled to the plunger stem762through a passage of the diaphragm spacer730. The boss724comprises a boss fluid flow passage726formed therethrough that fluidly interconnects the activation fluid cavity780, the plunger cavity768, and the actuation fluid side of the valve cavity770. The actuation fluid volume portion of the valve cavity770and process fluid volume portion of the valve cavity770are separated by the diaphragm720.

In some embodiments the valve700, the plunger fluid flow passage766and boss fluid flow passage726have a length and cross section such that plunger760is translated toward or away from the fluid actuation cavity780in the valve plate750by a change in pressure in the fluid activation cavity780before substantial pressure is applied to or reduced in the volume of the fluid actuation side of the valve cavity770between the back of the diaphragm720and diaphragm spacer730. Fitting790may serve to couple the pressure source to the fluid flow passage754. An O-ring764may be disposed in an annular channel769in plunger760and seal against the inner walls of assembly cavity710in valve plate750to seal pneumatic cavity780from other portions of the assembly cavity710.

In some embodiments of the valve700the plunger fluid flow passage766open to plunger cavity768and an opening728of the boss fluid flow passage726to a back side of diaphragm720and activation fluid side of valve cavity770allow fluid communication between plunger cavity768and valve cavity770when opening728of fluid flow passage726in boss724clears central passage of diaphragm spacer730.

One embodiment includes a method of operating a valve (200,700) that comprises the acts or steps of applying a fluid force to the backside of a plunger (260,760) and to the backside of a diaphragm in a diaphragm assembly, where the plunger and the backside of the diaphragm are fluidly coupled. Moving the plunger in a valve assembly cavity (210,710), the plunger comprises a plunger cavity (268,768) formed in a plunger stem (262762), and a plunger fluid flow passage (266,766) in the plunger. The plunger fluid flow passage (266,766) fluidly connects an actuation fluid cavity (280,780) in a valve plate (250,750) and the plunger cavity (268,768). The method further includes moving the diaphragm and the diaphragm assembly (219,719) in said valve assembly cavity (210,710) by application of the fluid force to open or close the valve against the valve seat (712), wherein the diaphragm assembly (219,719) comprises a diaphragm (220,720) and a boss (224724), said diaphragm assembly (219,719) secured between a diaphragm spacer (230,730) and a fluid block (240,740) in the valve assembly cavity (210,710). The diaphragm assembly (219,719) fluidly separating said a valve cavity (270,770) in the valve assembly (210,710) into a process fluid side and an actuation fluid side. The boss (224,724) is coupled to the plunger stem (262,762) through a passage of the diaphragm spacer (230,730). The boss (224,724) comprises a boss fluid flow passage (226,726) formed therethrough that fluidly interconnects the activation fluid cavity (280,780), the plunger cavity (268,768), and the actuation fluid side of said valve cavity (270,770). The method can include operating a valve where the force is applied by vacuum or reduced pressure of an actuating fluid through a plunger fluid flow passage266and plunger cavity268in plunger260and fluid flow passage226through boss224of diaphragm assembly219, said plunger and diaphragm assembly cooperate to allow fluid communication between the plunger fluid flow passage and the annular space of the actuation fluid side of valve cavity270behind diaphragm220. The method of can further comprise introducing fluid into a process fluid side of the valve cavity from an inlet fluid flow path772. The method can include controlling the flow of any process fluid or liquid. In some embodiments the process liquid flow that can be controlled can have a viscosity of between 100 and 20,000 centipoise through the fluid inlet772and fluid outlet744of the valve.

As will be realized after reading the above disclosure, embodiments of the valves as disclosed herein can be advantageously utilized in a wide variety of fluid systems, including fluid systems utilized in the pumping or dispense of chemicals in semiconductor manufacturing. For example, embodiments may be utilized with a pumping system, including for example, multi-stage pumping systems where multiple valve assembly cavities may be incorporated into a single fluid block such as240and250with flow paths machined therein. The use of such valves in these types of fluid systems may have numerous advantages as detailed hereinabove as, according to some embodiments, around 40% more fluid or air may be evacuated from a closed valve than a comparable valve without such fluid passages formed in the diaphragm.

Data showing the efficacy of embodiments as disclosed herein relative to previous diaphragm valves is included in the example below.

Assembled two new valve assemblies similar to those inFIG. 2and two older valve assemblies similar to those inFIG. 1in a four valve test block. Apply 60 pounds per square inch gas pressure to close valve and reduced pressure (“vacuum”) to open valves. Tee the inlet and outlet together and apply 45 (psi) pneumatic. Actuate the valves open and close to break valves in about 500 times. The test is to look for the volume difference in fluid volume displacement between the current and new valve. For the test, remove the tee from the fluid tubes; the fluid tubes are about 12 inches long standing straight up, tube inside diameter is 0.3 inches. Fill with isopropyl alcohol and cycle valves to get all air out. Use mineral oil viscosity 1148 centipoise at 20 degrees centigrade. Open all 4 valves. Mark the fluid column on all 4 tubes. Close all 4 valves and mark the fluid column. Measure the delta volume.

The results in Table 1 show the new valve has increased outlet volume (average was 0.59 cubic centimeters) compared to the old valve outlet volume of 0.37 cubic centimeters. The improvement in output volume was 37% for the new valves compared to the old valves. The time to close the new valve was slightly longer because an increase volume of viscous fluid was being displaced (4 seconds vs 3 seconds). The test results for the new valves that have a plunger fluid flow passage that fluidly connects an actuation fluid cavity with a boss fluid flow passage (226,726) and the actuation fluid side of the valve cavity show higher volume compared to the old valve which lacks the plunger flow passage and boss fluid flow passage. The increased outlet volume indicates more complete removal of fluid from trapped areas between the diaphragm and valve seat by applying pressure on the backside of the diaphragm in the actuation fluid side of the valve cavity. By applying actuating fluid to the back side of the diaphragm in the valve, the viscous mineral oil is forced out from between the diaphragm and valve seat resulting in a higher outlet volume. It will be understood that the Example refers to specific embodiments only and that any restrictive language, configurations, settings, values, etc. appearing therein will be taken to apply only to that embodiment and not to embodiments as disclosed herein generally.

As used herein, the terms comprises, comprising, includes, including, has, having or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, product, article, or apparatus. Further, unless expressly stated to the contrary, or refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead, these examples or illustrations are to be regarded as being described with respect to one particular embodiment and as illustrative only.

Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized encompass other embodiments as well as implementations and adaptations thereof which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms. Language designating such non-limiting examples and illustrations includes, but is not limited to: for example, for instance, e.g., in one embodiment, and the like.

Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the disclosure. It is to be understood that the forms of the disclosure shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the disclosure may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Changes may be made in the elements described herein without departing from the spirit and scope of the disclosure as described.