Pulse-purge diaphragm valve and related methods

Abstract

A diaphragm valve for gas analytical applications is provided, comprising: a valve cap with a plurality of process conduits extending therethrough; a valve body engageable with the valve cap and having a body interface with a recess; a diaphragm disposed between the valve cap and the valve body and having a process groove for circulating a fluid therethrough, the process groove engaging the recess; a plunger assembly disposed within the valve body, the plunger assembly including a plurality of plungers movable between a closed position in which the plungers engage the diaphragm and an open position in which the plungers are spaced apart from the diaphragm; and an actuation assembly including a gas inlet for allowing injection of an actuation gas, the actuation assembly including a purge system for purging an area located between the diaphragm and the body interface, whereby the actuation gas is used to purge the area.

Description

[Technical Field]

[0001] The technical field relates generally to systems and methods relating to valves, and more particularly to purge systems for diaphragm-sealed valves such as those used in gas analysis and / or gas chromatography applications. [Background technology]

[0002] In a diaphragm valve, communication between ports is blocked or allowed by forcing a plunger against or retracting a diaphragm, which is usually made of a soft / deformable material. Diaphragm valves can be equipped with a purge system configured to inject a purge gas into selected areas of the valve to purge impurities therefrom. A particularly important area to purge is the area below the diaphragm. Given that the diaphragm has some porosity, gas molecules / atoms can escape therethrough and contaminate the valve.

[0003] Existing purge systems typically require purge inlets, outlets, piping, fittings, and / or conduits to reach the desired area and effectively purge the valve. This additional hardware to operate the valve can increase the labor costs to manufacture the valve, the cabinet space required for the various components, and ultimately the price of the valve. Additionally, a periodic / continuous flow of purge gas is injected into the valve to ensure a clean environment within the valve, which can also increase the operating costs of the valve. Summary of the Invention [Problem to be solved by the invention]

[0004] In light of the above, there is a need for an improved valve with a simpler and more effective purge system, which is also easier to manufacture and overcomes the drawbacks associated with the difficulty of operating a continuous purge system. [Means for solving the problem]

[0005] According to a first aspect, a diaphragm valve for gas analysis applications is provided. The valve includes a valve cap with a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface. The valve also includes a valve body engageable with the valve cap, the body interface adapted to face the cap interface and including a recess, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recess. A diaphragm is disposed between the valve cap and the valve body and includes a process groove for allowing fluid circulation therethrough, the process groove being shaped and sized to engage with the recess in the valve body. The valve further includes a plunger assembly disposed within the valve body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger movable between a closed position in which the plunger engages the diaphragm and blocks fluid circulation along the process groove between the two process ports, and an open position in which the plunger is spaced from the diaphragm, thereby allowing fluid to circulate along the process groove. The valve also includes an actuation assembly including a gas inlet extending through the valve body to allow injection of an actuation gas to move the plunger between the open and closed positions, the actuation assembly further including a purge system for purging a purge region located between the diaphragm and the body interface, the actuation gas being used to purge the purge region.

[0006] According to one possible embodiment, the valve also includes a bottom cap connected to the valve body and defining an internal chamber together with the valve body, and a plunger assembly including an upper piston operably engaging the first plunger set and a lower piston engaging the second plunger set, the upper piston and the lower piston being provided within the internal chamber, whereby the internal chamber is in fluid communication with the purge region via the plunger passage.

[0007] According to one possible embodiment, the first set of plungers are normally open plungers and the second set of plungers are normally closed plungers.

[0008] According to one possible embodiment, the internal chamber includes an upper region located between the upper piston and the plurality of plunger passages, a lower region located between the lower piston and the bottom cap, and an intermediate region located between the upper piston and the lower piston, and the gas inlet is arranged to allow actuation gas to be injected into the intermediate region to actuate at least one of the upper piston and the lower piston.

[0009] According to one possible embodiment, the purge system comprises a controlled flow channel adapted to establish fluid communication between the middle region and the upper region.

[0010] According to one possible embodiment, the controlled flow channel comprises a first flow restrictor adapted to restrict the flow of fluid therethrough to build up pressure in the intermediate region.

[0011] According to one possible embodiment, the first flow restrictor is a first check valve having a first cracking pressure and configured to allow fluid to flow therethrough when the pressure in the intermediate region exceeds the first cracking pressure.

[0012] According to one possible embodiment, the controlled flow channel further includes a flow limiter having a passage in fluid communication with the outlet of the first check valve, the passage shaped and sized to limit the flow rate of the working gas from the middle region to the upper region.

[0013] According to one possible embodiment, the upper piston includes a recess, the flow limiter includes a removable insert adapted to engage the recess of the upper piston, and the passageway extends through the removable insert.

[0014] According to one possible embodiment, the passageway is about 0.5 cm between the middle region and the upper region. 3 / min ~ 2cm 3 / min.

[0015] According to one possible embodiment, the actuation assembly further includes a gas outlet arranged to establish fluid communication between the internal chamber and the ambient environment.

[0016] According to one possible embodiment, the gas outlet includes an outlet flow restrictor adapted to at least partially prevent gas from exiting the internal chamber, thereby directing the actuation gas through the plunger passage to the purge region.

[0017] According to one possible embodiment, the gas outlet is in communication with the upper region and the outlet flow restrictor includes an outlet check valve having an outlet cracking pressure configured to allow fluid flow therethrough when the pressure in the upper region exceeds the outlet cracking pressure.

[0018] According to one possible embodiment, the outlet cracking pressure is greater than the atmospheric pressure of the environment surrounding the diaphragm valve.

[0019] According to one possible embodiment, the outlet check valve has a closing pressure at which the outlet valve closes, and the pressure in the purge region oscillates between the outlet cracking pressure and the closing pressure.

[0020] According to one possible embodiment, the plungers have outer surfaces, and each plunger includes one or more grooves extending along its respective outer surface between its upper and lower ends to facilitate fluid communication between an upper region of the internal chamber and the purge region.

[0021] According to one possible embodiment, the grooves are helical and / or vertically oriented.

[0022] According to one possible embodiment, the plunger includes a plunger head adapted to engage the diaphragm, a plunger base adapted to be engaged by one of the upper piston and the lower piston, and a plunger body extending between the plunger head and the plunger base, wherein the plunger head, plunger base, and plunger body of one or more plungers are independent of each other and stacked within their respective plunger passages.

[0023] According to one possible embodiment, the plunger head and plunger base are substantially rigid, and the plunger body is made of a compressible material, an elastomeric material, or a combination thereof.

[0024] According to one possible embodiment, the plunger body comprises at least two adjacent portions extending between the plunger head and the plunger base, each portion having a different compressibility.

[0025] According to one possible embodiment, the plunger body is offset from the central longitudinal axis of the plunger.

[0026] According to one possible embodiment, the plunger base of each plunger is fully seated on a corresponding one of the upper and lower pistons.

[0027] According to one possible embodiment, the plunger base of each plunger is fixedly connected to a corresponding one of the upper and lower pistons.

[0028] According to one possible embodiment, the upper piston includes a central opening and a plurality of upper recesses and a plurality of upper protrusions, and the first plunger set is adapted to seat on the upper protrusions.

[0029] According to one possible embodiment, the lower piston includes a piston head adapted to extend through a central opening in the upper piston, the lower piston including a plurality of lower recesses and lower protrusions, and the second plunger set adapted to seat on the lower protrusions.

[0030] According to one possible embodiment, the central opening and the piston head are complementarily shaped.

[0031] According to one possible embodiment, the upper protrusion is shaped and configured to engage the lower recess, and the lower protrusion is shaped and configured to engage the upper recess.

[0032] According to one possible embodiment, the actuation assembly further includes an actuation system configured to selectively apply a force to the lower piston to move the second plunger set to the closed position.

[0033] According to one possible embodiment, the actuation system includes an actuation screw adapted to apply a force to the lower piston, and the bottom cap includes a storage mechanism operably engaging the actuation screw to indicate the position of the actuation screw.

[0034] According to one possible embodiment, the actuation screw includes notches distributed around the periphery of the head of the actuation screw, and the storage mechanism includes a set screw engageable with the notches of the actuation screw.

[0035] According to another aspect, a method for purging a region between a diaphragm and a valve body of a diaphragm valve is provided, the method including injecting a working gas into the diaphragm valve via a gas inlet, routing the working gas along a purge circuit to reach a purge region, pressurizing the purge region, and releasing the working gas via a gas outlet to purge the purge region.

[0036] According to one possible embodiment, the gas inlet communicates with an internal chamber provided in the diaphragm valve, and the step of injecting the working gas into the diaphragm valve includes the step of pressurizing the internal chamber to open the first check valve and allow the working gas to flow from the internal chamber to the purge region.

[0037] According to one possible embodiment, the step of directing the working gas along the purge circuit includes blocking the gas outlet to force the working gas to flow from the internal chamber to the purge region before exiting the valve via the gas outlet, allowing pressurization of the purge region.

[0038] According to one possible embodiment, the purge circuit is defined entirely within the diaphragm valve.

[0039] According to another aspect, a diaphragm valve for gas analysis applications is provided, the valve comprising: a valve cap having a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface; a valve body engageable with the valve cap, the valve body having a body interface adapted to face the cap interface and including a recess, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recess; and a diaphragm disposed between the valve cap and the valve body and having a process groove for circulating a fluid therethrough, the process groove shaped and sized to engage with the recess in the valve body. a plunger assembly adapted to be installed within the body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger adapted to selectively engage a diaphragm to control fluid circulation along the process groove; and an actuation assembly including an actuation system configured to enable injection of an actuation gas into the valve body to actuate the plunger assembly and displace the plungers, the diaphragm and body interface defining a purge region therebetween, and the actuation assembly including a purge system configured to deliver the actuation gas to the purge region to purge the purge region and remove impurities therefrom.

[0040] According to yet another aspect, a diaphragm valve for gas analysis applications is provided, the valve comprising: a valve cap having a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface; a valve body engageable with the valve cap, the valve body having a body interface adapted to face the cap interface and including recesses, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recesses; and a diaphragm disposed between the valve cap and the valve body, the diaphragm having a process groove for circulating a fluid therethrough, the process groove shaped and sized to engage the recesses in the valve body. a plunger assembly adapted to be installed within the valve body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger adapted to selectively engage a diaphragm to control fluid circulation along the process groove; an actuation assembly operably connectable to the plunger assembly, the actuation system including an actuation screw movable between an engaged position and a disengaged position capable of operating a diaphragm valve for gas analytical applications; and a storage mechanism including a set screw engageable with a first portion of the actuation screw to indicate that the actuation screw is in the engaged position, and a second portion of the actuation screw to indicate that the actuation screw is in the disengaged position.

[0041] Other configurations of the advantages of the present invention will be better understood by reading the exemplary implementations thereof with reference to the accompanying drawings. It should also be noted that the diaphragm valve embodiments described herein are intended to be exemplary only, and the configuration of one embodiment should not be understood as being limited to that particular embodiment, and that combinations and variations of the components described herein are possible and can be used. [Brief explanation of the drawings]

[0042] [Figure 1]FIG. 1 is a top perspective view of a diaphragm-sealed valve according to one possible embodiment. [Figure 2] 2 is a cross-sectional view of the valve of FIG. 1 showing a pair of pistons disposed within the valve, according to one embodiment. [Figure 3] 2A and 2B are top and exploded views of the valve of FIG. 1 showing various components of the valve, according to one embodiment. [Figure 4] 2 is a bottom perspective exploded view of the valve of FIG. 1 showing an internal chamber defined within the valve body, according to one embodiment. [Figure 5] FIG. 5 is an enlarged view of the valve cap shown in FIG. 4, showing the process ports open on the surface of the valve cap, according to one embodiment. [Figure 6] FIG. 4 is an enlarged view of the valve body and diaphragm shown in FIG. 3, showing a recess defined in a surface of the valve body and a process groove defined on the diaphragm, according to one embodiment. [Figure 7] 2 is a cross-sectional view of the valve of FIG. 1 showing the plunger extending into the plunger passage and a purge circuit within the valve, according to one embodiment. [Figure 7A] 2 is a cross-sectional view of the valve of FIG. 1 showing the plunger extending into the plunger passage and a purge circuit within the valve, according to one embodiment. [Figure 8] FIG. 1 is a perspective view of a portion of a plunger assembly, according to one embodiment. [Figure 9] FIG. 9 is an exploded view of a portion of the plunger assembly shown in FIG. 8, showing upper and lower pistons that are at least partially complementarily shaped, according to one embodiment. [Figure 10] FIG. 10 is an exploded view of the upper piston shown in FIG. 9, showing the flow limiter, according to one embodiment. [Figure 11a] FIG. 10 is an exploded top perspective view of an alternative embodiment of a plunger assembly showing a triangular push plate connectable to a lower piston, according to one embodiment. [Figure 11b]FIG. 11B is an exploded bottom perspective view of an alternative embodiment of the plunger assembly shown in FIG. 11a, showing an upper piston having a circular central opening for receiving the piston head of the lower piston, according to one embodiment. [Figure 12] FIG. 11b is a perspective view of multiple plungers seated on the piston shown in FIG. 11a. [Figure 13] FIG. 10 is an exploded view of an alternative embodiment of a plunger assembly showing a circular piston head engageable within a circular central opening, according to one embodiment. [Figure 14] FIG. 14 is a perspective view of a plurality of plungers seated on the piston shown in FIG. 13. [Figure 15] 10A-10C illustrate various embodiments of a plunger. [Figure 16] 10A-10C illustrate various embodiments of a plunger. [Figure 17] 10A-10C illustrate various embodiments of a plunger. [Figure 18] 10A-10C are various embodiments of a plunger. [Figure 19] 10A-10C illustrate various embodiments of a plunger. [Figure 20] 10A-10C illustrate various embodiments of a plunger. [Figure 21] FIG. 10 is a bottom plan view of the bottom cap of the valve showing a storage mechanism according to one embodiment. [Figure 22] FIG. 22 is a side perspective view of the storage mechanism shown in FIG. 21 showing a set screw engaging with a compression screw of the valve, according to one embodiment. [Figure 23A] 10 is a graph illustrating the change in pressure proximate to the inlet when the valve is actuated and when it is not actuated, according to one embodiment. [Figure 23B] 1 is a graph illustrating changes in pressure within a compartment or region of a valve, according to one embodiment. [Figure 23C] FIG. 1 is a schematic diagram showing the main components of a pulse purge system. [Figure 23D] 1 is a graph illustrating the change in concentration of impurities within a section or region of a valve, according to one embodiment. [Figure 24]FIG. 10 is a cross-sectional view of an alternative embodiment of a valve showing a second path for establishing fluid communication with an outer purge region, according to a possible embodiment. [Figure 25] FIG. 10 is a cross-sectional view of an alternative embodiment of a valve showing a second path for establishing fluid communication with an outer purge region, according to a possible embodiment. [Figure 26] FIG. 26 is a top perspective view of the valve body shown in FIG. 25 showing the gas outlet open on the body interface, according to one embodiment.

[0043] While the present invention will be described in conjunction with exemplary embodiments, it will be understood that it is not intended to limit the scope of the invention to such embodiments, but rather to cover all alternatives, modifications, and equivalents as defined herein. DETAILED DESCRIPTION OF THE INVENTION

[0044] The present invention relates to valves, more specifically, diaphragm-sealed valves, and related methods of operation. The diaphragm-sealed valves are referred to herein simply as "valves." The valves include numerous improvements, each of which can be implemented in the valve independently or in combination. For example, the valves can include an improved purge system configured to effectively purge one or more areas located around the diaphragm of the valve. The purge system can be configured to create a cycle of repeated pulses to purge one or more areas of the valve. In possible embodiments, the valves can include a plunger configured to facilitate purging the area around the diaphragm. In other embodiments, the valves can include a storage mechanism to facilitate storage of the valve once it has been turned off. The present invention will be better understood with a description of possible embodiments of the valves. While the different embodiments of the valves described below are diaphragm-sealed valves, it will be understood that other types of valves are also possible.

[0045] 1-26, possible embodiments of a diaphragm-sealed valve 10 are shown. The valve 10 includes a valve cap 100, a valve body 200 engageable with the valve cap 100, a diaphragm 300 disposed between the valve cap 100 and the valve body 200, a plunger assembly 400 disposed within the valve body 200, an actuation assembly 500 adapted to permit movement of the plunger assembly 400, and a bottom cap 600 connected to the valve body 200 opposite the valve cap 100. It will be understood that other components, such as various fasteners and fasteners (e.g., screws, nails, bolts, nuts, washers, springs, etc.), as well as sealing elements (e.g., O-rings, etc.), among others, can be provided within and / or with the valve 10. As described in connection with various embodiments, some of the components of the valve 10 (e.g., the valve cap 100, the valve body 200, and the bottom cap 600, among others) are generally cylindrical in shape.

[0046] In the illustrated embodiment, the valve body 200 and bottom cap 600 form an internal chamber 210 for receiving an actuation gas. As described below, the valve body 200 can be at least partially hollow, with the bottom cap 600 configured to cooperate with the valve body 200 to close the hollow section, thereby defining the internal chamber 210. Thus, it is understood that the valve 10 is pneumatically actuated and includes a gas inlet 502 in communication with the internal chamber 210 to provide actuation gas to the internal chamber 210 for displacing the plunger assembly 400. In the illustrated embodiment, the valve includes a "normally closed" (or up) plunger and a "normally open" (or down) plunger. The "normal" position of the plungers corresponds to when no actuation gas is injected. The "normal" or "default" plunger position is determined by the Belleville spring assembly 540 and the wave spring 546. When actuation gas is injected into the valve inlet 502, the pistons 420, 430 are separated, thereby moving the normally closed plunger toward an open (or lowered) position and the normally open plunger toward a closed (or raised) position. However, it will be understood that other methods for actuating the plunger assembly 400 are possible.

[0047] 1-5 , the valve cap 100 has a plurality of process conduits 102 extending through the thickness of the valve cap 100 and each terminating in a process port 104. The valve cap 100 further includes a cap interface 106 adapted to face the valve body 200 (and diaphragm 300) and upon which the process ports 104 open. It will be appreciated that, depending on the application of the valve 10, the valve cap 100 can include any suitable number of process conduits 102 arranged in any suitable configuration. For example, in this embodiment, the valve cap 100 includes six process conduits 102 arranged in a circle, such that the process ports 104 are correspondingly arranged in a circle on the cap interface 106. In other embodiments, the valve cap 100 can include four, eight, ten, twelve, or any other suitable number of process ports 102.

[0048] In this embodiment, the valve body 200 has a body interface 202 adapted to face the valve cap 100 so that the diaphragm 300 can be positioned between the valve cap 100 and the valve body 200, e.g., between the cap interface 106 and the body interface 202, when the valve 10 is assembled. More specifically, the diaphragm 300 has a first surface, such as a top surface 302, adapted to contact the cap interface 106 when placed between the valve cap 100 and the valve body 200, and a second surface, such as a bottom surface 304, adapted to contact the body interface 202.

[0049] 6 and 7, and with continued reference to previous figures, the valve body 200 includes a recess 204 defined in the surface of the body interface 202, such that the recess 204 faces the cap interface 106. The recess 204 is illustratively circular and generally concentric with the body interface 202 (e.g., the center of the body interface 202 corresponds to the center point of the recess 204). The process port 104 of the valve cap 100 is preferably positioned to be aligned with (i.e., open into) the recess 204 when the valve 10 is assembled (i.e., when the valve cap 100 and the valve body 200 are connected together). In some embodiments, the valve cap 100 and the valve body 200 can be connected to one another using a central fastener 207 and a pair of dowel pins 205, although it will be understood that other configurations and / or connection tools are possible and can be used. In some embodiments, the central fastener 207 may include a sealing element such as an O-ring adjacent to the head of the fastener or a sealant provided along the threaded section to prevent air intrusion through a gap between at least the valve cap 100 and the central fastener 207.

[0050] 6 and 7, the valve body 200 further includes a plurality of plunger passages 206 extending at least partially therethrough, with first ends open at respective locations along the recesses 204 and second ends opposite the first ends opening into corresponding openings on the internal chamber 210. As described further below in connection with the plunger assembly 400, the plunger passages 206 are each shaped and sized to receive a plunger 402 and open into the recesses 204 between two of the process ports 104.

[0051] In this embodiment, the diaphragm 300 includes a process groove 306 shaped and sized to align with and engage the recess 204 in the valve body 200. Thus, similar to the recess 204, the process groove 306 is adapted to align with the process port 104 in the valve cap 100 and the plunger passage 206 in the valve body 200. It should be understood that the process groove 306 is adapted to cooperate with the cap interface 106 to form a channel configured to allow fluid to circulate between at least two of the process ports 104. More specifically, the diaphragm 300 engages the cap interface 106 such that a surface of the cap interface 106 covers the process groove 306, forming a channel. In this embodiment, fluid can be injected into the process groove 306 via one of the process conduits 102, and the fluid can then flow along the formed channel to, for example, reach the process port 104 of a second one of the process conduits 102.

[0052] As seen in FIG. 7 , the plunger assembly 400 is illustratively adapted to be housed within the valve body 200, and more specifically, within the internal chamber 210. The plunger assembly 400 includes multiple plungers 402 slidably fitted within corresponding ones of the plunger passages 206, with the plungers 402 movable between at least two positions. In this embodiment, each plunger 402 is movable between a closed position in which the plunger 402 engages a process groove 306 in the diaphragm 300 to prevent fluid flow between at least two adjacent process ports 104, and an open position in which the plunger 402 is spaced from the diaphragm 300, thereby allowing fluid to flow along the process groove 306. To reduce the risk of a plunger 402 becoming clogged within a corresponding plunger passage 206, the plunger passage 206 preferably has a diameter slightly larger than the diameter of the widest component of the plunger 402. The specific structure and components of the plungers 402 are described further below.

[0053] In some embodiments, as previously described, the plungers 402 can be of two types, commonly referred to as “normally closed” and “normally open” plungers. As further described below, each plunger 402 of a given type is actuated together with other plungers of that same type. In other words, the plungers 402 of a given type are either all in a closed position or all in an open position. In this embodiment, the normally closed plungers are biased toward a closed position, while the normally open plungers are biased toward an open position. It will be understood that the normally open plungers form a first plunger set 402, while the normally closed plungers form a second plunger set 402. In the illustrated embodiment, the plunger assembly 400 also includes a pair of pistons 420, 430 that operably engage the plungers 402 to move the plungers 402 up and down within their respective plunger passages 206. More specifically, plunger assembly 400 includes a first piston, such as upper piston 420, that operably engages the first plunger set (i.e., the normally open plungers), and a second piston, such as lower piston 430, that operably engages the second plunger set (i.e., the normally closed plungers).

[0054] Generally speaking, and with reference to FIGS. 7-10 , the pistons 420, 430 of the plunger assembly 400 are generally circular and parallel to the diaphragm 300. In this embodiment, the upper piston 420 illustratively includes a central opening 424, and the lower piston 430 includes a piston head 434 shaped and sized to extend through the central opening 424 of the upper piston 420. It will be appreciated that the central opening 424 and the piston head 434 may be complementarily shaped to allow the pistons to move relative to one another while preventing the pistons from contacting one another and / or interfering with their movement. In one such embodiment, the upper and lower pistons may be manufactured using 3D printing techniques to enable their assembly.

[0055] Additionally, each of the pistons can include a respective push plate 422, 432 upon which the plunger 402 can rest, such that each piston 420, 430 pushes and / or pulls its respective push plate 422, 432 upon operation of the actuation assembly 500. In this embodiment, the upper push plate 422 is integrally formed as part of the upper piston 420, although it will be understood that other configurations are possible. In some embodiments, the lower push plate 432 is also integrally formed as part of the lower piston 430, while in other embodiments, the lower push plate 432 is a separate component, as seen, for example, in FIG. 11 . Alternatively, the lower push plate 432 can be integrally formed as part of the lower piston 430 and have a generally circular shape, as shown, for example, in FIGS. 9 and 13 .

[0056] In some embodiments, the pistons (i.e., upper piston 420 and lower piston 430) and / or their corresponding push plates 422, 432 are preferably shaped and sized to engage only their corresponding plunger sets 402 (i.e., without contacting or interfering with the movement of the other plunger set). Furthermore, the pistons 420, 430 can be configured so that the plungers 402 are fully seated on the corresponding pistons or partially seated on them. In other words, the pistons can be adapted to push against the entire cross section of the plungers 402 (as seen in FIGS. 7, 8, and 12) or a portion thereof where the pistons contact around approximately half of the bottom end of the plungers 402 (as seen in FIGS. 14 and 25). It should be understood that by pushing the entire lower end of the plunger 402, the plunger 402 can be kept relatively straight within the plunger passage 206, thus providing a generally uniform sealing force against the diaphragm 300 when the plunger is in the closed position, whereas by pushing only a portion of the lower end, the plunger 402 can be tilted slightly within the plunger passage 206, thus providing a non-uniform sealing force against the diaphragm 300.

[0057] Various exemplary embodiments of the plunger assembly 400 are shown in the accompanying figures and are described below. In the embodiment seen in FIGS. 8-10, the upper piston 420 has a plurality of upper recesses 426 and upper protrusions 428 disposed about a central opening 424, and the lower piston 430 has a plurality of lower recesses 436 and lower protrusions 438 disposed about a piston head 434. The recesses and protrusions of each piston are preferably complementarily shaped so that the upper protrusions 428 are positioned within the lower recesses 436 and the lower protrusions 438 are positioned within the upper recesses 426 when the pistons are assembled. In the illustrated embodiment, the plunger 402 is adapted to be engaged by the protrusions of the piston, whereby, in this embodiment, the protrusions 428, 438 are shaped and configured to engage the entire diameter of the plunger 402. More specifically, the upper protrusions 428 are adapted to engage with a first plunger set, and the lower protrusions 438 are adapted to engage with a second plunger set.

[0058] 11 and 12 , the piston head 434 illustratively has a circular shape, but it will be understood that it can have any suitable shape. In the illustrated embodiment, the lower piston 430 includes a lower push plate 432 that is removably connected to the piston head 434 and is complementarily shaped relative to the central opening 424 of the upper piston 420. In this embodiment, the lower push plate 432 has a generally triangular shape, whereby each corner of the lower push plate 432 engages with one plunger of the second plunger set 402 (as best seen in FIG. 12 ). In this case, the upper push plate 422 is the top surface of the upper piston 420 and is adapted to directly engage with the plungers 402 of the first plunger set. As seen in FIG. 12 , the shape and size of the lower push plate 432 allow each plunger set 402 to be fully seated on the corresponding push plate 422, 432.

[0059] 13 and 14, yet another embodiment of the plunger assembly 400 is shown. In this embodiment, an upper push plate 422 and a lower push plate 432 include upper and lower recesses 426 and 436, respectively. The number of recesses in each push plate can correspond to the number of plungers 402 in each plunger set. For example, in this embodiment, each plunger set 402 includes three plungers, and therefore each push plate includes three recesses. The recesses are shaped and sized to allow the push plates to actuate (i.e., move up and down) the pistons without contacting the plungers 402 engaged by other ones of the push plates. As seen in FIG. 14, each push plate 422, 432 is configured to contact approximately half of the bottom end of the corresponding plunger set 402, with the remaining half of the plunger engaging one of the recesses 426, 436 to avoid contact between both the pistons and their components.

[0060] While the push plates 422, 432 and corresponding plungers 402 are formed as independent / separate components in the illustrated embodiment, it will be understood that in other embodiments the plungers and push plates can have other configurations, for example, can be formed as a single component. Alternatively, the plungers can be fixedly connected to the push plates, for example, using screws or other fasteners.

[0061] 15-20 in addition to FIG. 7, in some embodiments, the plunger 402 includes a plunger base 406 engageable with one of the pistons at a lower end of the plunger base 406. The plunger 402 further includes a plunger head 408 adapted to engage the diaphragm 300 (i.e., the process groove) from below when the plunger 402 is in the closed position, and a plunger body 410 extending between the plunger base 406 and the plunger head 408. The components of the plunger 402 can be made from a generally rigid material, although other materials are possible, as further described below.

[0062] As seen in FIG. 20 , the components of the plunger 402 are independent of one another (i.e., are separate components) and can be stacked within the plunger passage 206, although a “single-unit” plunger 402 can also be used, as seen in FIG. 15 . In these embodiments, the plunger base 406 and plunger head 408 have substantially the same shape, size, and / or configuration. More specifically, the plunger base 406 and plunger head 408 are substantially cylindrical and have a diameter slightly smaller than the diameter of the plunger passage 206 to avoid interference / contact between the valve body 200 and the plunger 402.

[0063] For example, it is known that manufacturing defects can occur in various components of the plunger assembly 400, such as the piston, push plate, plunger, etc., which can cause differences or misalignment in the length of one or more plungers 402 within their respective plunger passages 206, resulting in uneven sealing forces being applied to the diaphragm 300. Accordingly, adjustments may be necessary to avoid damage to the plunger 402, valve body 200, diaphragm 300, and / or to ensure proper operation of the valve 10.

[0064] In some embodiments, the plunger body 410 can be shaped and configured to adjust the plunger head 408 relative to the diaphragm 300. More specifically, the plunger body 410 can be configured to position the plunger head 408 generally laterally relative to the diaphragm 300 (i.e., axially aligned within its plunger passage) so that the plunger head 408 applies a generally uniform sealing force to the diaphragm 300. For example, the plunger body 410 can be comprised of a stack of Belleville spring washers, or a compressible and / or elastomeric material (such as a spring or cushion) having compressibility adapted to adjust the alignment of the plunger head 408 when engaged with the diaphragm 300. More specifically, if the plunger head 408 were to apply a higher pressure to the diaphragm than necessary (because the plunger was manufactured with a non-uniform length), the excess compressive force would be absorbed by the elastomeric material. Thus, the compressible plunger body element can compensate for geometric imperfections (flatness, parallelism, etc.) of the plunger or other valve components, local thickness variations of the diaphragm, etc. This configuration of the plunger allows for the application of force across the entire cross-sectional area of ​​the plunger body. Here, the compressible central section 410 is cylindrical, but could be any shape, such as hollow, conical, hourglass, etc.

[0065] As seen in FIG. 16 , the plunger body 410 can also be generally cylindrical and have a diameter similar to that of the plunger base 406 and plunger head 408. In the embodiment of FIG. 18 , the plunger body 410 includes at least two compressible body portions 412 extending between the plunger base 406 and the plunger head 408, whereby each body portion 412 has its own compressibility. The compressible body portions 412 can be useful for balancing uneven forces applied to the plunger base 406 by one of the pistons, for example, when the piston engages only a portion (e.g., half) of the diameter of the plunger base 406. In some embodiments, the piston presses against half of the plunger base 406, such that the sealing force applied to the diaphragm can be uneven across the cross-section of the plunger head 408. Thus, a plunger body 410 having two or more compressible body portions 412 can be adapted to correct or compensate for uneven sealing forces.

[0066] In other embodiments, such as those in FIGS. 15 and 17 , the plunger body 410 can have a smaller diameter than the plunger base 406 and / or plunger head 408 and can be displaced relative to the central longitudinal axis of the plunger 402 ( FIG. 17 ) to adjust the plunger head 408 (e.g., if an uneven force is applied to the plunger base 406). It should be understood that in order for the displaced plunger body 410 to adjust the plunger head 408 in a generally consistent manner, the radial position of the plunger 402 must remain substantially the same. In other words, rotation of the plunger 402 within the plunger passage 206 must be prevented in order to maintain the plunger body 410 in the proper radial position for adjusting the force applied by the plunger head 408 on the diaphragm 300. For example, the shapes of the plunger passage 206 and plunger components can be non-circular so that rotation of the plunger 402 is prevented without impeding vertical movement of the plunger 402. It is understood that other suitable methods for preventing rotational movement of plunger 402 within each plunger passage 206 are possible and may be used.

[0067] In yet another embodiment of the plunger body 410, as shown in FIGS. 19 and 20 , the plunger body 410 can have a spherical shape so that uneven forces applied by the piston and / or plunger base 406 can be accommodated by the spherical design of the plunger body 410. It should be understood that the configuration of each embodiment of the plunger 402 described herein is simply exemplified herein and can be modified, simplified, altered, omitted, and / or replaced depending on the particular application for which the plunger is intended and / or the desired end result, as would be apparent to one of ordinary skill in the art. In some embodiments, the spherical plunger body 410 can have a diameter that approximately matches the diameter of the plunger base 406 and / or plunger head 408. Thus, compressive forces applied to the plunger 402 when in the closed position can cause the plunger body 410 (due to its compressible material) to expand outward and contact the walls of the plunger passageway. As a result, the deformation of the plunger body 410 is reduced / limited due to its larger diameter, thus increasing its compressibility. The life of the plunger body 410 may also be increased due to reduced deformation and therefore reduced stress on the components of the plunger 402.

[0068] 2-4 , actuation assembly 500 can include an actuation system 538 configured to enable operation of valve 10. More specifically, actuation system 538 can be operated between an engaged configuration, in which actuation gas can be injected to actuate plunger assembly 400, and a disengaged configuration, in which injection of actuation gas does not actuate plunger assembly 400. In this embodiment, actuation system 538 includes a Belleville spring assembly 540 including a stack of Belleville spring washers 542 that cooperates with lower piston 430. Actuation system 538 can also include a compression screw 544 configured to apply a load / force to the stack of Belleville spring washers 542, and thus to lower piston 430. As such, lower piston 430 is biased upward via actuation system 538 (e.g., when compression screw 544 is tightened), normally-closed plunger 402 is biased toward the closed position. It will be appreciated that actuation system 538 can include other biasing means, such as a standard spring or a polymer bushing, to enable operation of valve 10, such as by biasing lower piston 430 upward. In this embodiment, upper piston 420 is biased downward (e.g., toward lower piston 430) by suitable means. In the illustrated embodiment, wave spring 546 is provided within valve body 200 above upper piston 420 and adapted to apply a downward force thereto. Thus, normally open plunger 402 is effectively biased toward the open position.

[0069] When stored for extended periods, the normally-closed plunger of known valves continually presses against the diaphragm. Over time, creeping can change the shape of the diaphragm's process groove, reducing its height and potentially increasing flow restriction. Reducing or eliminating that compressive force can mitigate / prevent this phenomenon and its adverse effects. In other words, moving the actuation system 538 to the disengaged configuration loosens the compression screw 544, allowing the lower piston (and corresponding plunger) to move away from the diaphragm.

[0070] 21 and 22 , the valve 10 can include a storage mechanism 610 configured to operably engage the compression screw 544 and indicate the position of the compression screw 544. Thus, determining the state of the valve 10 (e.g., operating, standby, stored, etc.) can be facilitated by the configuration of the storage mechanism 610 based on the position of the compression screw 544. In this embodiment, the storage mechanism 610 includes a set screw 612 that extends through the bottom cap 600 to engage the compression screw 544. Additionally, the compression screw 544 can include a notch or recess 545 into which the set screw 612 can extend when the compression screw is in place. The set screw 612 can aid in positioning the compression screw 544 in a desired position and can facilitate determining the state of the valve 10.

[0071] The described embodiment is illustrative, and it is understood that other mechanisms, devices, components, and / or methods can be used to determine the state of the valve. For example, a guide indentation, groove, or marking could be used instead to allow the user to determine whether the valve is in a "storage" or "in-use" configuration depending on the rotational / angular position of the compression screw 544 relative to the bottom cap 600, using the set screw 612 or other similar guide. In the example shown in FIG. 21 , a spring plunger 610 is provided in the bottom cap and presses against the preload screw. A recess 545 is formed in the preload screw 544 to provide a tactile feedback when the spring plunger ball moves across the recess. The recess 545 is positioned to allow sufficient preload pressure release (typically between 1 / 4 and 1 / 2 turn). When the valve is ready to be used / installed, the end user simply screws the preload screw all the way in to restore the valve's operating preload.

[0072] In the illustrated embodiment, the actuation assembly 500 is operable to actuate both plunger sets 402 between their open and closed positions. As described above, the valve 10 is pneumatically actuated, whereby an actuation gas is injected into the valve body 200 to control the distance between the upper piston 420 and the lower piston 430. As shown in FIG. 2 , when the two pistons are not actuated, they are urged toward each other by the Belleville spring assembly 540 and the wave spring 546, so that the two pistons are in contact. The actuation mechanism 500 preferably includes a pneumatic actuator for supplying actuation gas between the upper piston 420 and the lower piston 430 via the gas inlet 502. When the valve is actuated, the gas pushes the upper piston 420 upward, thereby sliding the normally open plunger toward the closed position, and then pushes the lower piston 430 downward, thereby allowing the lower push plate and / or the normally closed plunger 402 to move downward toward the open position, thereby balancing the bias of both pistons. It should be appreciated that when actuation gas is no longer injected, the biasing effect of Belleville spring assembly 540 and wave spring 546 returns pistons 420, 430 to their original positions (ie, pre-actuation).

[0073] As seen in FIGS. 2 and 7 , the upper piston 420 and the lower piston 430 are disposed within an internal chamber 210 formed by the valve body 200 and the bottom cap 600. In this embodiment, the internal chamber 210 generally includes an upper region 212 located between the upper piston 420 and the plunger passage 206, a bottom region 214 located between the lower piston 430 and the bottom cap 600, and an intermediate region 216 located between the upper piston 420 and the lower piston 430. As described above, an actuation gas is injected between the upper piston 420 and the lower piston 430 (i.e., into the intermediate region 216) to actuate the pistons. A gas inlet 502 is illustratively in fluid communication with the intermediate region 216, allowing the actuation gas to be injected therein. In the illustrated embodiment, the gas inlet 502 is disposed generally coincident with the intermediate region 216 to facilitate the injection of the actuation gas, although it is understood that other configurations are possible and the gas inlet 502 can be disposed in other suitable locations. Additionally, the internal chamber 210 can include a sealing element 211 configured to prevent the working gas from escaping the desired region(s). In this embodiment, a pair of O-rings are disposed between the pistons 420, 430 and the walls of the internal chamber 210, so that the working gas injected into the internal chamber 210 is forced between the pistons.

[0074] 6, 7, and 10, actuation assembly 500 further includes a purge system 510 configured to effectively purge a region 512 (hereinafter referred to as the "purge region" 512) located between the bottom surface of diaphragm 304 and body interface 202. In some embodiments, as seen in FIG. 6, purge region 512 includes an inner purge region 512a corresponding to the region located below diaphragm 300 along recess 204 in valve body 200 (i.e., below process groove 302 in diaphragm 300), and an outer purge region 512b corresponding to the region between recess 204 and the inner wall of valve body 200. In this embodiment, purge system 510 includes an inner purge circuit 514 that is integrally formed within a component of valve 10 and includes one or more channels adapted to deliver gas / fluid to purge region 512. As described further below, in the illustrated embodiment, the purge circuit allows the working gas injected through the gas inlet 502 to flow along the channel to reach the purge region 512 and then exit the interior of the valve 10, effectively purging the purge region 512. In other words, the purge system 510 allows at least a portion of the injected working gas to act as a purge gas to effectively purge the region below the diaphragm 300 (i.e., the purge region 512).

[0075] In some embodiments, the channels of the purge circuit 514 can define one or more paths for routing and / or forcing the working gas to the inner purge region 512 a and / or the outer purge region 512 b. In the embodiment of FIG. 7 , the purge circuit 514 includes a first controlled flow channel 516 configured to establish fluid communication between the middle region 216 (i.e., where the working gas is initially injected) and the upper region 212. The controlled flow channel 516 illustratively extends through the upper piston 420 to effectively connect the middle region 216 and the upper region 212, although it will be understood that other configurations are possible, such as, for example, providing one or more external conduits for routing gas from one region to another.

[0076] As the working gas enters the upper region 212, the gas is routed to the inner purge region 512a before exiting the valve 10, effectively purging the region 512a. As seen in FIG. 7A, the purge circuit 514 includes a first path along which the working gas can flow to purge the inner purge region. In this embodiment, the first path includes A) injecting the working gas into the middle region 216, B) the working gas flowing through the controlled flow channel 516, C) the working gas flowing into the upper region 212, D) the working gas flowing into the inner purge region 512a, and D) the working gas exiting the valve 10.

[0077] In this embodiment, the upper region 212 is in fluid communication with the purge region 512 through a plunger passage 206 extending through the valve body 200. The plunger passage 206 can be slightly larger than the plunger 402 inserted therein, thereby creating a gap through which fluid (e.g., actuation gas) can flow to reach the purge region 512. It is understood that gas flowing through the plunger passage 206 is generally restricted to flow into the inner purge region 512a because the plunger passage 206 opens onto the recess 204. In some embodiments, as seen in FIGS. 15-18 , the plunger 402 can include a groove 404 extending along its outer surface to facilitate fluid communication between the upper region 212 and the purge region 512. The groove 404 can be spirally shaped and / or vertically oriented, although it is understood that other configurations are possible. For example, plunger 402 may include a channel (not shown) that extends through the structure of plunger 402 (rather than around the exterior surface) to allow fluid to reach purge region 512.

[0078] 7 , the controlled flow channel 516 can include a first flow restrictor 518 adapted to at least partially prevent fluid flow through the controlled flow channel 516 to allow actuation gas to accumulate in the middle region 216 to actuate the pistons 420, 430, as described above. In one exemplary embodiment, the first flow restrictor 518 includes a first check valve 519 configured to block fluid flow therethrough until a predetermined pressure in the middle region 216 is reached. The first check valve 519 has a first cracking pressure corresponding to the pressure at which the first check valve 519 opens, allowing fluid to flow through the controlled flow channel 516 to the upper region 212. The cracking pressure typically corresponds to the minimum upstream pressure at which the check valve operates and can be provided in units of psi, psig, kPa, MPa, etc.

[0079] In the illustrated embodiment, the valve 10 includes a gas outlet 504 for allowing the actuation gas to exit the valve 10. In some embodiments, the gas outlet 504 is positioned to establish fluid communication between the internal chamber 210 and the ambient environment. Thus, the pressure within the valve 10 can be controlled and / or regulated by allowing a portion of the gas to exit the valve via the gas outlet 504. In this embodiment, the gas outlet 504 specifically establishes fluid communication between the upper region 212 of the internal chamber 210 and the ambient environment. Thus, the actuation gas located within the upper region 212 can flow toward the purge region 512 (via the plunger passage 206) and / or toward the outlet 504.

[0080] In this embodiment, the purge system 510 includes an outlet flow restrictor 520 adapted to at least partially prevent gas from flowing through the outlet 504, thus forcing the gas up the plunger passage 206 and into the purge region 512. The outlet flow restrictor 520 may be a check valve 521 having an outlet cracking pressure set to allow fluid to flow therethrough when the pressure in the upper region 212 is equal to or greater than the outlet cracking pressure. It should be understood that because the pressure in the upper region 212 is approximately the same as the pressure in the inner purge region 512a, the pressure in the inner purge region 512a must also reach the outlet cracking pressure before the outlet check valve 521 can open. It is also understood that the outlet cracking pressure is preferably higher than the first cracking pressure so that the fluid (e.g., working gas) can be routed to the purge region 512 before being discharged via the outlet 504. In some embodiments, the outlet cracking pressure is set above the atmospheric pressure of the surrounding environment to maintain the upper region 212 and inner purge region 512a above said atmospheric pressure during normal use of the valve 10.

[0081] In some embodiments, the flow of gas between the middle region 216 and the upper region 212 can be controlled. For example, as seen in FIGS. 7 and 10 , the controlled flow channel 516 can include a flow limiter 522 shaped and configured to limit the flow rate of gas flowing therethrough. The flow limiter 522 can simply include a passage 524 of reduced diameter that communicates with the outlet of the first flow restrictor 518 (e.g., first check valve 519) to limit the flow rate of gas entering the upper region 212 to a predetermined flow rate. The flow limiter 522 advantageously allows the valve 10 to operate while reducing the amount of actuation gas injected through the inlet 502 to purge the purge region 512. The passage 524 of the flow limiter 522 can have any suitable shape and size, such as, for example, a straight passage, a spiral passage, a serpentine passage, or the like.

[0082] 10, the flow limiter 522 can include a removable insert 525 engageable with an insert slot 526 in the upper piston 420 adjacent the outlet of the first check valve 519. In this embodiment, a passageway 524 is defined through the removable insert 525, such that placing the insert 525 in the insert slot 526 connects the passageway 524 to the outlet of the first check valve 519 to restrict the flow of fluid. Multiple removable inserts 525 can include passageways 524 of different sizes and / or shapes, thereby allowing the flow rate to be selectively adjusted based on the selection of the insert 525. In some embodiments, the flow rate of fluid through the flow limiter 522 can be reduced by approximately 0.5 cm. 3 / min ~ approx. 2cm 3 / min. Alternatively, or additionally, a single removable insert 525 can be provided with multiple passages 524 having different diameters, such that changing the orientation (i.e., radial position) at which insert 525 engages insert slot 526 effectively changes passage 524 connecting check valve 519 to upper region 212.

[0083] As shown in FIGS. 23A-23C, and with reference to FIGS. 2 and 7, first check valve 519 and / or outlet check valve 521 further have respective closing pressures (i.e., first closing pressure and outlet closing pressure) at which the check valves close. More specifically, when the pressure in upper region 212 and inner purge region 512a reaches the outlet cracking pressure, outlet check valve 521 opens, allowing gas to exit the valve through outlet 504, effectively drawing debris and other impurities from inner purge region 512a. As gas exits the valve, inner purge region 512a is purged, causing the pressure to drop. When it reaches the outlet closing pressure, outlet check valve 521 closes accordingly, allowing gas to again be routed to inner purge region 512a. Pressure builds in upper region 212 and inner purge region 512a until the outlet cracking pressure is reached, and the cycle repeats.

[0084] Existing purged gas chromatography (GC) diaphragm valves typically require a continuous purge flow, delivered through a flow orifice connected to a carrier gas supply. This consumes excess carrier gas, and when using capillary columns, the purge flow is on the same order as the carrier flow. Therefore, this type of configuration is inconvenient and expensive in terms of carrier gas, primarily when using helium.

[0085] The purpose of the above-described purge system is to establish an inert zone below the diaphragm to prevent atmospheric permeation through the diaphragm. This is a real problem with non-purged diaphragm valves. Atmospheric permeation through the diaphragm results in carrier gas contamination that interferes with analytical results. Purging can also reduce and potentially eliminate the buildup of harmful impurities below the diaphragm. The proposed valve and method use a "static" purge process instead of relying on dynamic purging, i.e., continuous flow. The proposed method relies on using carrier gas to build pressure within a target volume (i.e., the purge region) and then reducing it to a value just above atmospheric pressure, diluting the air into the target volume, i.e., the space below the diaphragm. As can be seen in the exemplary embodiment in Figure 23D, after several cycles, there is no air below the diaphragm.

[0086] Continuing with reference to FIGS. 23A-23C in addition to FIGS. 7-10, upon actuation of the valve (typically a three-way solenoid valve) controlling the inlet of the carrier / working gas supply, carrier gas flows through the first check valve 519 (CV1) and through the flow orifice 524 (R1), restricting actual flow into the volume and slowly pressurizing it. When the pressure in that region reaches the cracking pressure of the second check valve 533 (CV2), e.g., approximately 1 PSIG, the check valve 533 (CV2) opens. Once opened, flow through the second check valve is greater than flow through the orifice 524. This is achieved by selecting an orifice size (e.g., in the range of 0.0005 inches (0.0127 mm)) that is much smaller than the cross-section of the second check valve. As a result, pressure decreases into the purge region, causing the second check valve to close. In some embodiments, it may be useful to provide a filter or filtration system (not shown) connected to the first check valve (CV1) to effectively filter the gas before it reaches the orifice (R1) to prevent it from blocking / clogging the orifice. It is understood that any other restriction(s) may be used instead of the orifice (R1), such as, for example, a restriction filter.

[0087] As shown in Figure 23B, there is a difference between the opening and closing pressures of the first and second check valves, resulting in valve hysteresis. Pressure cycling continues until the working gas / carrier gas supply valve is shut off. At this stage, flow stops within the volume / purge region, but the second check valve closes, isolating the volume from the atmosphere, allowing the volume to further pressurize to a value between the closing pressure and the cracking pressure. After several pressure cycles, dilution effects nearly completely remove all air from the purge volume. Therefore, working gas consumption occurs only when the working gas inlet / solenoid valve is open. Typically, a flow rate target of approximately 1 SCCM (standard cubic centimeter per minute), driven by the working pressure and the size of the orifice 524, is sufficient to ensure adequate purging while effectively limiting excess gas usage.

[0088] Referring to FIG. 23C, as well as FIGS. 2, 7, and 10, valve SV1 is used to actuate the valve. When SV1 is actuated, the carrier / working gas pressurizes the volume between the pistons, forcing the pistons apart. The upper piston plate incorporates a first check valve 519 and a flow orifice 524, identified as CV1 and R1 in FIG. 23C. As shown in FIG. 7, a second check valve 533, i.e., CV2, is fitted to the side wall of the valve. Alternatively, the second check valve 533 (CV2) can be installed at the end of a tube connected to a volume vent defined by the valve upper piston.

[0089] 23A and 23B, the diagrams show that the pressure within the inner purge region 512a oscillates between an outlet cracking pressure and an outlet closing pressure (FIG. 23B), creating a pulse-purge cycle in which the purge region is effectively purged. In some embodiments, the outlet cracking pressure can be between about 0.5 psig and about 1.5 psig, such that the pressure within the purge region 512 rises above the pressure of the ambient environment, although it is understood that other pressures are possible. It should be understood that the unit "psig" refers to pounds per square inch gauge and typically indicates the pressure difference between a supply tank or chamber and the ambient air. Furthermore, the outlet closing pressure can be any suitable pressure that enables a pulse-purge cycle as described herein.

[0090] The purge system uses actuation gas injected through the gas inlet to perform the purge, resulting in a pulse-purge cycle during normal use of the valve. The pressure at which the actuation gas is injected can depend on the load applied to the lower piston via the compression screw. For example, the actuation gas can be injected at a pressure between about 50 psig and about 70 psig, although it is understood that other pressures can be used depending on the particular application for which the valve is intended and / or the desired end result. For example, and as shown in FIG. 23A, actuation gas is injected through inlet 502 to provide sufficient pressure to effectively actuate valve 10. In this embodiment, the pressure adjacent to the inlet remains approximately constant while valve 10 is actuated (i.e., turned on) and drops back to approximately zero when the valve is turned off. Note that when the valve is adjusted, the pressure in the purge region no longer fluctuates between the outlet cracking pressure and the outlet closing pressure, as shown in FIG. 23B, and thus the volume is isolated to a pressure between the outlet cracking pressure and the outlet closing pressure. The pulse purge cycle also reduces the amount of gas used during normal use of the valve, as it eliminates the need for a continuous purge flow through the valve 10 .

[0091] This means that each time the valve is actuated, the volume defined between the diaphragm and the upper piston cycles between the cracking pressure of CV2 and the closing pressure. This cycle continues until SV1 closes. At that moment, the valve is not actuated and there is no flow through the valve until the next actuation. Purge gas can reach the space below the diaphragm by flowing around the plunger.

[0092] As previously explained, the static purge circulation occurs only when the valve is actuated, so the carrier / working gas is used as the purge gas source only while the valve is actuated. Because the system uses the working gas as the purge gas, no additional inlet purge port is required. Another advantage of this method is that the volume / area below the diaphragm is always above atmospheric pressure, helping to reduce atmospheric diffusion back into the valve and greatly reducing impurity permeation from the sample to the purge area.

[0093] It should be noted that both check valves can be mounted externally to the valve. However, the additional tubing and fittings required would significantly reduce the compact advantage of a fully integrated design. This trade-off may be necessary, for example, if it is desired to recover the purge gas for recycling purposes or appropriate waste disposal. Accordingly, in some embodiments, outlet 504 can be adapted to have tubing connected to it to route the gas exiting the valve to another component / device (e.g., for gas recycling or disposal). In other embodiments, locating the check valves externally to valve 10 may be useful when using unfiltered and / or dirty working gases, whereas valve 10 can be connected to a filtration system (not shown) via additional tubing used to connect the check valves (or other devices) to the valve. It should also be noted that valve 10 can include any suitable number of check valves (or other similar and / or restriction devices), either within its structure (i.e., fully integrated), external to its structure (i.e., connected to extra tubing and fittings), or a combination thereof.

[0094] With further reference to Figures 8 and 15, as well as Figures 23A, 23B, 23C, 2, 7, and 10, the spacing / gap between the plunger and its corresponding plunger passageway can be very small, limiting flow or air exchange between the actuation line and the purge area located below the diaphragm. This limitation can slow the purge process and limit the effectiveness of the proposed purge system. To limit the impact of such tight tolerances between the plunger and the passageway sidewalls, a spiral / spiral groove can be formed on the outer surface of the plunger, as best shown in Figure 15. The groove 404 ensures constant fluid exchange between the base and head portions of the plunger, allowing the pulse purge method to be effective.

[0095] Referring now to FIG. 23D in addition to FIGS. 2, 7, 10, and 23A-23C, the pulse-purge method can help remove or at least reduce the amount of impurities (e.g., debris from the environment, residual gas from a previous measurement, etc.) present in a particular region or compartment of the valve 10. As seen in FIG. 23D, the concentration of impurities decreases substantially exponentially with each subsequent pulse of the pulse-purge cycle. In one exemplary embodiment, the purged volume is substantially equal to 0.5 mL, and the gas flow through outlet 504 is maintained at approximately 1 mL / min. Thus, the purged volume is completely refreshed / purged every 30 seconds. Assuming approximately 50% fluid dilution every 30 seconds (i.e., the amount of air is substantially halved after each 30 seconds), operating the valve 10 for approximately 5 minutes refreshes the purged volume approximately 10 times, reducing the amount of air, and therefore the concentration of impurities, to less than approximately 0.1% (as shown in FIG. 23D). It is understood that operating the valve for an additional 5 minutes can reduce the amount of air in the purged volume to less than about 1 PPM, and therefore it can be assumed that there is no more air in the purged volume. However, it is understood that other configurations are possible depending on the desired results and settings of the various components of valve 10 (e.g., fluid flow through outlet 504, volume of the purged area, etc.).

[0096] 24-26 , purge circuit 514 may alternatively or additionally include a channel defining a second path that allows actuation gas injected through inlet 502 to reach purge region 512. For example, the second path may be configured to route actuation gas from inlet 502 to outer purge region 512b, while the first path may be configured to route actuation gas to inner purge region 512a, as described above. Thus, purge circuit 514 may allow actuation gas to reach inner purge region 512a (via the first path) and outer purge region 512b (via the second path), such that most of the area below diaphragm 300 is purged (e.g., on both sides of recess 204) during use of valve 10.

[0097] As seen in FIG. 24 , the purge circuit 514 may include one or more outer channels 528 extending through a portion of the valve body 200 to establish fluid communication between the upper region 212 of the internal chamber 210 and the outer purge region 512b. In this embodiment, the outer channels 528 are generally straight (e.g., vertical) and unobstructed, although it is understood that other configurations are possible. For example, the outer channels 528 may have a serpentine configuration to reduce the flow rate of gas entering the outer purge region 512b. Furthermore, in the illustrated embodiment, the purge circuit 514 includes two outer channels 528 positioned generally opposite each other within the valve body 200. However, it is understood that the purge circuit 514 may include any other suitable number of outer channels 528, such as, for example, a single outer channel or more than two outer channels.

[0098] It should be understood that outer purge region 512b can therefore undergo substantially the same pulse-purge cycle as described above. Indeed, both inner purge region 512a and outer purge region 512b are in fluid communication with upper region 212, which connects to outlet 504. Thus, in this embodiment, the pressure in inner purge region 512a varies in substantially the same manner as the pressure in outer purge region 512b, although other configurations are possible.

[0099] 25, the outer channel 528 can be in direct fluid communication with the gas inlet 502 without being connected to the internal chamber 210. In this embodiment, the purge circuit 514 includes a first channel 515a extending between the gas inlet 502 and the internal chamber 210 and a second channel 515b extending from the first channel 515a at a first end thereof and opening into the outer purge region 512b at an opposite end thereof. Thus, the working gas injected through the gas inlet 502 can flow into the internal chamber 210 through the first channel 515a and toward the purge region 512b through the second channel 515b. In this case, it should be understood that the second channel 515b is one of the outer channels 528, and the purge circuit 514 illustratively includes a single outer channel 528. However, it is understood that other configurations are possible.

[0100] In the illustrated embodiment, the outer channel 528 may include a second flow restrictor 532 adapted to at least partially prevent fluid flow therethrough, thus defining a second controlled flow channel 530. More specifically, the second controlled flow channel 530 may be configured to establish fluid communication between the gas inlet 502 and the outer purge region 512b. The second flow restrictor 532 may prevent fluid flow through the second controlled flow channel 530 to force the actuation gas along the first channel 515a and into the internal chamber 210 to actuate the piston.

[0101] In one exemplary embodiment, the second flow restrictor 532 includes a second check valve 533 configured to block fluid flow therethrough until a predetermined pressure upstream of the second check valve 533 is reached. The second check valve 533 has a second cracking pressure corresponding to the pressure at which the second check valve 533 opens to allow fluid to flow through the second controlled flow channel 530 and into the purge region 512 (i.e., the outer purge region 512b). It should be understood that the intermediate region 216, the first channel 515a, and the second channel 515b are in fluid communication with one another such that the pressure is approximately the same in each of these portions. Thus, it should be understood that when the pressure in the intermediate region 216 reaches the second cracking pressure, the second check valve 533 effectively opens, allowing fluid flow to reach the outer purge region 512b.

[0102] Additionally, the purge circuit 514 may further include inner passages shaped and configured to connect various portions of the purge regions 512 a, 512 b to one another, thus allowing for a more uniform distribution of gas within these regions and / or allowing for more efficient purging of the purge regions. For example, as seen in FIG. 25 , the purge circuit 514 may include a plunger purge channel 534 positioned to establish fluid communication between the outer purge region 512 b and a region of the purge region 512 proximate the central fastener 207 (e.g., between a recess in the valve body and the central fastener 207). It will be understood that alternative or additional channels / passages may be provided within the structure of the valve 10 to allow actuation gas to flow into and out of various regions and / or portions to allow for more efficient purge cycles.

[0103] 25 and 26, the gas outlet 504 is in fluid communication with the outer purge region 512b through an outlet opening 505 defined in the valve body 200 within the outer purge region 512b. The gas outlet 504 may include an outlet flow restrictor 520, as previously described, to ensure that the pressure within the outer purge region 512b reaches an outlet cracking pressure before exiting the valve 10. The gas outlet 504 may have an orifice shaped and sized to allow a predetermined purge flow (i.e., the flow of working gas exiting the purge region) to exit the valve 10. For example, in some embodiments, the gas outlet 504 is shaped and sized to allow a purge flow of approximately 1 sccm of gas to exit the valve, although other configurations are possible. Again, it is understood that in this embodiment, the outer purge region 512b undergoes a pulse-purge cycle similar to that previously described in connection with the inner purge region 512a.

[0104] As can be appreciated, the valve embodiments described herein enable purging of the region located between the diaphragm and the valve body using a working gas and via a pulse cycle. In other words, a purge system can be used to create a controlled atmosphere / environment in the region below the diaphragm (i.e., the region being purged), which is typically filled with a carrier gas. It should be understood that when the purge region is filled with a carrier gas, permeation exchange between the process flow along the diaphragm and the purge region consists of carrier gas molecules moving from one side of the diaphragm to the other. Therefore, when the nature of the process changes (e.g., when the fluid flowing along the process flow changes), new molecules attempt to pass through the diaphragm (via permeation). These molecules are captured by the purge system and / or diluted in the volume of the purge region. Advantageously, if these molecules are inherently hazardous, they can then be disposed of in a controlled and safe manner.

[0105] In some embodiments, each cycle (i.e., each pulse) of the purge system can be adapted to effectively purge the same area repeatedly or to purge various areas according to a predetermined sequence or as needed. Additionally, the purge circuit of the described valves is advantageously defined entirely within the valve, i.e., the purge circuit is an integral part of the valve and is completely contained therein, eliminating the need for external tubing and / or specific purge gas inlets / outlets in addition to the actuation gas inlets / outlets. It should be noted that the pulse-purge cycle described above can be adapted for other applications and may be possible using fluids other than the actuation gas of the valve 10.

[0106] A corresponding method for purging a purge region located around (e.g., below) the diaphragm using one of the described embodiments can include the steps of: a) injecting a working gas into the valve via a gas inlet, b) routing the working gas along a purge circuit to reach the purge region, c) pressurizing the purge region, and d) releasing the working gas from within the valve via a gas outlet, effectively purging the valve. It should also be noted that the method can include connecting the purge region to a vacuum in addition to or instead of pressurizing the purge region.

[0107] Additionally, while embodiments of the valve and its corresponding components comprise particular geometric configurations as described and illustrated herein, not all of these components and geometries are required and therefore should not be construed in a limiting sense. It should be understood that it will be apparent to those skilled in the art that other suitable components and their associations, as well as other suitable geometric configurations, can be used in the valve, as briefly described herein and as can be readily inferred from this specification by those skilled in the art. Furthermore, it is understood that descriptions of locations, such as "top," "bottom," "upper," "lower," "left," and "right," should be interpreted in the context of the figures and should not be considered limiting, unless otherwise specified.

[0108] Furthermore, in the context of this description, all elongated objects are considered to have an implied "longitudinal axis" or "centerline," such as the longitudinal axis of a plunger, or the centerline of a passageway of a purge circuit, and terms such as "connected" and "connectable," or "attached" and "attachable," are considered to be interchangeable in that the present invention includes various components for assembling a resulting fully assembled and fully operational valve and / or associated plunger assembly and / or actuation assembly.

[0109] Additionally, the components of the present invention and / or steps of the method(s) described herein may be modified, simplified, changed, omitted, and / or interchanged without departing from the scope of the present invention, depending on the particular application for which the invention is intended and the desired end result, as briefly illustrated herein and as would be apparent to one of ordinary skill in the art.

[0110] Several alternative embodiments and examples are described and illustrated herein. The above-described embodiments of the present invention are intended to be illustrative only. Those skilled in the art will appreciate the configuration of each embodiment and the possible combinations and variations of the components. Those skilled in the art will further appreciate that any of the embodiments can be provided in any combination with the other embodiments disclosed herein. It is understood that the present invention may be embodied in other specific applications or configurations. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention should not be limited to the details given herein. Thus, while specific embodiments have been illustrated and described, many modifications come to mind without significantly departing from the invention.

[0111] In this disclosure, an embodiment is one example or implementation of a diaphragm valve. The various appearances of "one embodiment," "one embodiment," or "some embodiments" do not necessarily all refer to the same embodiment. While various configurations may be described in the context of a single embodiment, the configurations may also be provided separately or in any suitable combination. Conversely, a diaphragm valve may be described herein in the context of separate embodiments for clarity, but it may also be implemented in a single embodiment. References herein to "some embodiments," "one embodiment," "one embodiment," or "other embodiments" mean that a particular configuration, structure, or characteristic described in connection with an embodiment is included in at least some embodiments, but not necessarily all embodiments.

[0112] It should also be understood that like features in the drawings have been given like reference numerals, and in order to maintain clarity of the drawings, some reference numerals have been omitted if already identified in a previous figure.

Claims

1. 1. A diaphragm valve for gas analytical applications, comprising: a valve cap having a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface; a valve body engageable with the valve cap, the valve body having a body interface adapted to face the cap interface and including a recess, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recesses; a diaphragm disposed between the valve cap and the valve body, the diaphragm having a process groove for circulating a fluid therein, the process groove shaped and sized to engage with the recess in the valve body; a plunger assembly disposed within the valve body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger movable between a closed position in which the plunger engages the diaphragm and blocks fluid circulation along the process groove between two process ports, and an open position in which the plunger is spaced from the diaphragm, thereby allowing fluid to circulate along the process groove; an actuation assembly including a gas inlet extending through the valve body to allow injection of an actuation gas to move the plunger between the open position and the closed position, the actuation assembly further including a purge system for purging a purge region located between the diaphragm and the body interface, the actuation gas being used to purge the purge region; A diaphragm valve including:

2. the diaphragm valve includes a bottom cap connected to the valve body and defining an interior chamber with the valve body; 2. The diaphragm valve of claim 1, wherein the plunger assembly includes an upper piston operably engaging a first plunger set and a lower piston engaging a second plunger set, the upper piston and the lower piston being provided within the internal chamber, whereby the internal chamber is in fluid communication with the purge region via the plunger passage.

3. 3. The diaphragm valve of claim 2, wherein said first set of plungers are normally open plungers and said second set of plungers are normally closed plungers.

4. the internal chamber includes an upper region located between the upper piston and the plurality of plunger passages, a lower region located between the lower piston and the bottom cap, and an intermediate region located between the upper piston and the lower piston; 4. The diaphragm valve of claim 2 or 3, wherein the gas inlet is positioned to allow an actuation gas to be injected into the intermediate region to actuate at least one of the upper piston and the lower piston.

5. The diaphragm valve of claim 4 , wherein the purge system includes a controlled flow channel adapted to establish fluid communication between the middle region and the upper region.

6. 6. The diaphragm valve of claim 5, wherein the controlled flow channel includes a first flow restrictor configured to restrict fluid flow therethrough to build pressure within the intermediate region.

7. 7. The diaphragm valve of claim 6, wherein the first flow restrictor is a first check valve having a first cracking pressure and configured to allow fluid to flow therethrough when the pressure in the intermediate region exceeds the first cracking pressure.

8. 8. The diaphragm valve of claim 7, wherein the controlled flow channel further includes a flow limiter having a passage in fluid communication with an outlet of the first check valve, the passage shaped and sized to limit the flow rate of the working gas from the middle region to the upper region.

9. 9. The diaphragm valve of claim 8, wherein the upper piston includes a recess, the flow limiter includes a removable insert adapted to engage the recess in the upper piston, and the passageway extends through the removable insert.

10. The passageway is 0.5 cm between the middle region and the upper region. ３ / min ~ 2cm ３ 10. The diaphragm valve of claim 8 or 9, shaped and sized to provide a flow rate of between 1000 and 1500 kJ / min.

11. The diaphragm valve of any one of claims 8 to 10, wherein the actuation assembly further comprises a gas outlet positioned to establish fluid communication between the internal chamber and an environment surrounding the diaphragm valve.

12. 12. The diaphragm valve of claim 11, wherein the gas outlet includes an outlet flow restrictor adapted to at least partially prevent gas from exiting the internal chamber, thereby routing the actuation gas through the plunger passage to the purge region.

13. the gas outlet communicates with the upper region, and the outlet flow restrictor includes an outlet check valve having an outlet cracking pressure; 13. The diaphragm valve of claim 12, wherein the outlet check valve is configured to open and permit fluid flow therethrough when the pressure in the upper region exceeds the outlet cracking pressure.

14. 14. The diaphragm valve of claim 13, wherein the outlet cracking pressure is greater than atmospheric pressure of an environment surrounding the diaphragm valve.

15. 15. The diaphragm valve of claim 13 or 14, wherein the outlet check valve has a closing pressure at which the outlet check valve closes, and the pressure in the purge region oscillates between the outlet cracking pressure and the closing pressure.

16. 16. The diaphragm valve of claim 4, wherein the plungers have outer surfaces, and each plunger includes one or more grooves extending along its respective outer surface between its upper and lower ends to facilitate fluid communication between the upper region and the purge region of the internal chamber.

17. 17. The diaphragm valve of claim 16, wherein the grooves are spiral and / or vertically oriented.

18. 18. The diaphragm valve of claim 2, wherein the plunger includes a plunger head adapted to engage the diaphragm, a plunger base adapted to be engaged by one of the upper piston and the lower piston, and a plunger body extending between the plunger head and the plunger base, and the plunger head, plunger base, and plunger body of one or more plungers are independent of one another and stacked within their respective plunger passages.

19. 20. The diaphragm valve of claim 18, wherein the plunger head and plunger base are rigid, and the plunger body is made of a compressible material, an elastomeric material, or a combination thereof.

20. 20. The diaphragm valve of claim 18 or 19, wherein the plunger body includes at least two adjacent portions extending between the plunger head and the plunger base, each portion having a different compressibility.

21. A diaphragm valve according to any one of claims 18 to 20, wherein the plunger body is offset from a central longitudinal axis of the plunger.

22. 22. A diaphragm valve according to any one of claims 18 to 21, wherein the plunger base of each plunger is fully seated on a corresponding one of the upper and lower pistons.

23. 23. The diaphragm valve according to any one of claims 18 to 22, wherein the plunger base of each plunger is fixedly connected to a corresponding one of the upper piston and the lower piston.

24. 24. The diaphragm valve of claim 2, wherein the upper piston includes a central opening, a plurality of upper recesses, and a plurality of upper protrusions, and the first plunger set is adapted to seat on the upper protrusions.

25. 25. The diaphragm valve of claim 24, wherein the lower piston includes a piston head adapted to extend through the central opening of the upper piston, the lower piston including a plurality of lower recesses and a plurality of lower protrusions, and the second plunger set adapted to seat on the lower protrusions.

26. 26. The diaphragm valve of claim 25, wherein the central opening and piston head are complementarily shaped.

27. 27. The diaphragm valve of claim 25 or 26, wherein the upper protrusion is shaped and configured to engage the lower recess, and the lower protrusion is shaped and configured to engage the upper recess.

28. 28. The diaphragm valve of claim 2, wherein the actuation assembly further includes an actuation system having an actuation screw configured to selectively apply a force to the lower piston to move the second plunger set to the closed position.

29. 30. The diaphragm valve of claim 28, wherein the bottom cap includes a storage mechanism operably engaging the actuation screw to indicate the position of the actuation screw.

30. 30. The diaphragm valve of claim 29, wherein the actuation screw includes notches distributed around the periphery of the head of the actuation screw, and the storage mechanism includes a set screw engageable with the notches of the actuation screw.

31. 1. A method for purging a purge region between a diaphragm and a valve body of a diaphragm valve, comprising: injecting a working gas into the diaphragm valve via a gas inlet; directing the working gas along a purge circuit to reach the purge region; pressurizing the purge region; and releasing the working gas through a gas outlet to purge the purge region.

32. 32. The method of claim 31 , wherein the gas inlet communicates with an internal chamber disposed within the diaphragm valve, and wherein injecting the working gas into the diaphragm valve includes pressurizing the internal chamber to open a first check valve and force the working gas to flow from the internal chamber to the purge region.

33. 33. The method of claim 32, wherein routing the working gas along the purge circuit includes blocking the gas outlet to force the working gas to flow from the internal chamber to the purge region and enable pressurization of the purge region before exiting the valve through the gas outlet.

34. A method according to any one of claims 31 to 33, wherein the purge circuit is defined entirely within the diaphragm valve.

35. The method of any one of claims 31 to 34, wherein the diaphragm valve comprises any one of the features of claims 1 to 30.

36. 1. A diaphragm valve for gas analytical applications, comprising: a valve cap having a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface; a valve body engageable with the valve cap, the valve body having a body interface adapted to face the cap interface and including a recess, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recesses; a diaphragm disposed between the valve cap and the valve body, the diaphragm having a process groove for circulating a fluid therein, the process groove shaped and sized to engage with the recess in the valve body; a plunger assembly adapted to be installed within the valve body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger adapted to selectively engage the diaphragm to control fluid circulation along the process groove; an actuation assembly including an actuation system configured to allow injection of an actuation gas into the valve body to actuate the plunger assembly and displace the plunger; The diaphragm valve, wherein the diaphragm and the body interface define a purge region therebetween, and the actuation assembly includes a purge system configured to deliver the actuation gas to the purge region to purge the purge region and remove impurities therefrom.

37. 1. A diaphragm valve for gas analytical applications, comprising: a valve cap having a plurality of process conduits extending therethrough, the valve cap having a cap interface, each of the process conduits including a process port opening onto the cap interface; a valve body engageable with the valve cap, the valve body having a body interface adapted to face the cap interface and including a recess, the valve body including a plurality of plunger passages extending therethrough, whereby the plunger passages open onto the recesses; a diaphragm disposed between the valve cap and the valve body, the diaphragm having a process groove for circulating a fluid therein, the process groove shaped and sized to engage with the recess in the valve body; a plunger assembly adapted to be installed within the valve body, the plunger assembly including a plurality of plungers slidably fitted within corresponding ones of the plunger passages, each plunger adapted to selectively engage the diaphragm to control fluid circulation along the process groove; an actuation assembly including an actuation system including an actuation screw operably connectable to the plunger assembly and operable between engaged and disengaged positions to operate the diaphragm valve for gas analytical applications; a storage mechanism including a set screw engageable with a first portion of the actuation screw to indicate that the actuation screw is in the engaged position, and a second portion of the actuation screw to indicate that the actuation screw is in the disengaged position.

38. 38. The diaphragm valve of claim 37, further comprising any one of the features of claims 1-30.

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