AIR OPERATED DOUBLE DIAPHRAGM PUMP WITH DIFFERENTIATED CHECK VALVE SIZING

Abstract

In one example, a displacement pump has a suction side including a suction check valve, and a discharge side including a discharge check valve. The discharge side and suction side are each configured for selective fluid communication with each other, and the suction check valve defines a flow area that is relatively larger than a flow area defined by the discharge check valve.

Description

FIELD OF THE INVENTION

The present disclosure is generally concerned with fluid systems and fluid system components. More specifically, at least some of the disclosed embodiments concern fluid system components such as diaphragm pumps and associated pump suction and discharge configurations.

BACKGROUND

Diaphragm pumps are well suited for a variety of applications, including semiconductor manufacturing processes for example. One of the characteristics of many diaphragm pumps is that they produce a pulsating discharge. While some pulsing of the discharge flow is unavoidable, excessive pulsing can be problematic. In order to limit the occurrence of pulsing, some diaphragm pumps are equipped with a relatively small discharge check valve in the pump discharge line.

Another concern with some diaphragm pumps concerns the suction and discharge configuration of those pumps. In many instances, the suction and discharge lines are the same size. The same is true of the check valves that are typically included in the pump suction and discharge lines. That is, the suction and discharge check valves are the same size. Such an arrangement can be somewhat convenient in terms of manufacturing, and in reducing the total number of different types of parts that are required for the pump.

Notwithstanding these considerations however, the use of suction and discharge check valves that are the same size can be problematic. This is particularly so where the suction check valve has the same relatively small size, compared to the fluid chambers, as the discharge check valve. For example, the overall operational efficiency of the pump is compromised in arrangements where the suction check valve has the same relatively small size as the discharge check valve. In particular, the relatively small size of the pump suction check valve increases pump suction head loss and, accordingly, compromises the overall operational efficiency of the pump. That is, a relatively small pump suction check valve limits the discharge flow rate of the pump.

As another example, pulsing in the discharge line can occur as the result of the use of suction and discharge check valves that are the same size. Such pulsing typically occurs in displacement-type pumps such as diaphragm pumps, and typically does not occur during normal operation in other types of pumps, such as centrifugal pumps for example. Excessive pulsing in the discharge can increase wear on pump components and also results in undesirable fluctuations in discharge pressure and volume.

The use of relatively small suction check valves gives rise to other concerns as well. For example, relatively small suction check valves can contribute to cavitation. Cavitation can be a major cause of wear in the pump, and may cause the generation of particles as pump components wear and are broken down. These particles can contaminate the fluid being pumped by the pump and may compromise pump and/or system performance. As well, the occurrence of cavitation can produce loud noises during pump operation.

In light of problems such as those noted above, it would be useful to be able to configure a pump with good discharge characteristics, such as limited or no pulsation. Further, it would be helpful to reduce internal head loss on the suction side of the pump. As well, it would be useful to reduce or eliminate cavitation in the pump.

Aspects of Some Example Embodiments

It should be noted that the embodiments disclosed herein do not constitute an exhaustive summary of all possible embodiments, nor does this brief summary constitute an exhaustive list of all aspects of any particular embodiment(s). Rather, this brief summary simply presents selected aspects of some example embodiments. It should further be noted that nothing herein should be construed as constituting an essential or indispensable element of any invention or embodiment. Rather, various aspects of the disclosed embodiments may be combined in a variety of ways so as to define yet further embodiments. Such further embodiments are considered as being within the scope of this disclosure. As well, none of the embodiments embraced within the scope of this disclosure should be construed as resolving, or being limited to the resolution of, any particular problem(s). Nor should such embodiments be construed to implement, or be limited to implementation of, any particular technical effect(s) or solution(s).

Disclosed embodiments are generally concerned with fluid systems and associated components and control systems. Embodiments within the scope of this disclosure may include any one or more of the following elements, and features of elements, in any combination: a diaphragm pump; an air-operated diaphragm pump; an air-operated double diaphragm (AODD) pump; a bellows pump; a diaphragm pump including one or more plastic components; a diaphragm pump including one or more polytetrafluoroethylene (PTFE) components, such as a pump body and/or a pump head; a diaphragm pump having suction and discharge connections that are different respective sizes; a diaphragm pump having a suction check valve and a discharge check valve, the suction and discharge check valves being of different respective sizes; a diaphragm pump having a suction check valve and a discharge check valve, the suction check valve having a larger size than the discharge check valve; a suction check ball and a discharge check ball that is smaller than the suction check ball; a diaphragm pump including a suction check ball and a discharge check ball that is smaller than the suction check ball; a diaphragm pump including a suction inlet bore and a discharge outlet bore that is smaller than the suction inlet bore; a diaphragm pump including a suction check bore and a discharge check bore that is smaller than the suction check bore; and, a suction check ball and a discharge check ball that are each made of plastic.

In view of the present disclosure, a variety of different embodiments are possible. Some examples of such embodiments are set forth below.

In a first example embodiment, a diaphragm pump includes a suction check valve that is larger than a discharge check valve of the diaphragm pump.

In a second example embodiment, a diaphragm pump includes a suction check ball that is larger than a discharge check ball of the diaphragm pump, such that the suction check valve provides a relatively larger, freer flowing fluid path, than the fluid path of an associated discharge check valve. In this embodiment, the suction check ball has a larger outside diameter than an outside diameter of the discharge check ball.

In a third example embodiment, a diaphragm pump that includes a suction check bore that is larger than a discharge check bore of the diaphragm pump. Thus, the suction check valve has a flow path area that is larger than a flow path area of the discharge check valve.

In further example embodiments, any of the preceding embodiments of a diaphragm pump include one or more diaphragms.

In still further example embodiments, any of the preceding embodiments of a diaphragm pump include two diaphragms. One example of such a further embodiment is an air operated double diaphragm (AODD) pump.

In still other example embodiments, any of the preceding embodiments of a diaphragm pump, including one or more components of a suction check valve and discharge check valve, are substantially made of plastic.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings contain figures of some example embodiments to further clarify various aspects of the present disclosure. It will be appreciated that these drawings depict only some embodiments of the disclosure and are not intended to limit its scope in any way. The disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a section view of a first example fluid pump that includes suction and discharge check valves that are the same size;

FIG. 2 is a front view of a second example fluid pump in connection with which embodiments of the invention can be employed;

FIG. 3 is a section view of the fluid pump disclosed in FIG. 2;

FIG. 4 is another section view of the fluid pump disclosed in FIG. 2; and

FIG. 5 is a section view of a fluid pump including differentiated check valve sizing.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

The present disclosure is generally concerned with fluid systems and fluid system components. More specifically, at least some of the disclosed embodiments concern fluid system components such as diaphragm pumps and associated pump suction and discharge configurations.

In one particular example, an air operated double diaphragm pump includes suction and discharge bores, each of which is in fluid communication with a respective suction check valve and discharge check valve. In this example embodiment, the suction bore has a larger diameter, or cross-section area, than the diameter, or cross-section area, of the discharge bore. Correspondingly, the fluid passageway defined by the suction check valve is relatively larger than the fluid passageway defined by the discharge check valve. Thus, a suction check ball of the suction check valve has a larger outside diameter than the outside diameter of a discharge check ball of the discharge check valve.

Among other things, the differentiated sizes of the suction and discharge check valves allows for improvement in one or more operational parameters of a displacement-type pump, such as a diaphragm pump for example. More specifically, such size differentiation can provide for an improvement in suction, and decrease in pulsation of the discharge, relative to the values of such parameters of an otherwise similar or identical pump. The size difference between the suction and discharge check valves may also help reduce cavitation.

Embodiments of the invention may be especially well suited for use in connection with displacement-type pumps, such as diaphragm pumps, that use the movement, which can be reciprocating movement between two positions, of one or more displaceable elements, such as diaphragms for example, to pump fluid. This is because problems such as discharge pulsation, for example, are typically not experienced in non displacement-type pumps. One example of such a non displacement-type pump is a centrifugal pump.

A. General Aspects of Some Example Embodiments

In general, fluid system components disclosed herein may be used in a variety of different applications, and may be particularly useful in fluid systems for semiconductor manufacturing processes, although the scope of the invention is not limited to such applications. Such fluid systems may employ, for example, deionized (DI) water, corrosive agents and materials including but not limited to acids and bases, gases, other fluids, and combinations of any of the foregoing. Such fluids may be hot, highly pressurized, reactive, and/or pure fluids.

The temperatures of fluids employed in such systems, such as acids for example, may be anywhere in the range of about 1 degree C. to about 180 degrees C., or in any sub-range falling within that range including, for example, about 100 degrees C. to about 180 degrees C. These temperatures are provided by way of example, and in some instances may be even higher than about 180 degrees C. As another example, some systems may employ process fluids that may reach temperatures as high as about 200 degrees C. to about 220 degrees C., or higher. Note that as used herein, “fluid” embraces compressible fluids such as gases, incompressible fluids such as liquids, combinations of gases and liquids, and combinations of one or more gases and/or one or more liquids with solids.

The fluid system components disclosed herein, including diaphragm pumps, suction check valves, and discharge check valves, and their components, may be constructed with a variety of components and materials including, but not limited to, non-reactive and substantially non-reactive materials, non-metallic and substantially non-metallic materials, rubber, plastics such as polymers, and composites. It should be noted that non-reactive and substantially non-reactive materials embrace a variety of materials, including both metals, such as stainless steel for example, as well as non-metallic materials, such as plastics for example. Examples of the aforementioned polymers may include perfluoroalkoxy (PFA) and polytetrafluoroethylene (PTFE), which can be machined or otherwise formed into various components, such as pump bodies, pump heads, and diaphragms for example. Fluoroelastomers (FKM), and perfluoroelastomers (FFKM) may also be employed. These materials may or may not be virgin materials.

In certain applications, metals such as steel including stainless steel, copper, titanium, brass, nickel, aluminum, and alloys and combinations of any of the foregoing metals, may be used. Examples of such alloys include copper-nickel alloys (CNA), and nickel-copper alloys (NCA).

B. Aspects of Some Example Fluid Pumps

In general, embodiments of the invention can be employed in connection with any of a variety of different pumps, such as diaphragm pumps and, more specifically, air operated double diaphragm (AODD) pumps. Some particular examples of diaphragm pumps with which embodiments of the invention can be employed are the ‘EVOLVE 55D PUMP’ diaphragm pump manufactured by Trebor (A Unit of IDEX Corporation), and the ‘EVOLVE 55E PUMP’ diaphragm pump manufactured by Trebor (A Unit of IDEX Corporation). Details concerning the structure and operation of the ‘EVOLVE 55D PUMP’ diaphragm pump, and the ‘EVOLVE 55E PUMP’ diaphragm pump are disclosed, respectively, in Appendix 1 (EVOLVE 55D PUMP Operation/Maintenance Manual) and Appendix 2 (EVOLVE 55E PUMP Operation/Maintenance Manual) to the ‘Related Application’ identified herein.

More generally, embodiments of the invention can be employed in connection with any displacement-type pump including, but not limited to, diaphragm pumps, and bellows pumps. As such, the scope of the invention is not limited to the example diaphragm pumps disclosed herein.

With particular reference now to FIG. 1, an example of a fluid pump 100, aspects of which can be employed in some embodiments, is disclosed. The example fluid pump 100 includes a suction connection 102 and a discharge connection 104. The suction side of the fluid pump 100 includes a pair of suction check valves 106, each of which includes a suction check ball 106a. Similarly, the discharge side of the fluid pump 100 includes a pair of discharge check valves 108, each of which includes a discharge check ball 108a. As will be apparent from FIG. 1, the suction check balls 106a are the same size as the discharge check balls 108a. As such, the suction check valves 106 and discharge check valves 108 may be referred to herein as being undifferentiated with respect to each other, in terms of their respective sizes.

As suggested above, the fluid pump 100 disclosed in FIG. 1 can implement various aspects of the embodiments disclosed herein in order to help avoid, or at least attenuate, some of the problems noted herein. For example, in one configuration, the suction connection 102 is relatively larger than the discharge connection 104. Thus, and in view of the relationship Q=v×A (where Q is flow rate, v is velocity, and A is the area through which the flow passes), the flow area ‘A’ of the suction connection 102 may be relatively larger than a flow area of the discharge connection 104. This difference in flow area can be reflected, for example, in terms of the respective inside diameters of the suction connection 102 and the discharge connection 104.

Correspondingly, in this same example, one or more elements of the suction check valves 106 relating to the flow through the suction check valves 106 may be relatively larger than the corresponding element(s) of the discharge check valves 108. For example, the suction check balls 106a may each have a relatively larger outside diameter than the outside diameter of the discharge check balls 108a. Except for the aforementioned changes, the structure and operation of the modified fluid pump 100 may remain largely unchanged relative to the structure and operation of the unmodified fluid pump 100.

With attention now to FIGS. 2-4, another example fluid pump 200, aspects of which can be employed in some embodiments, is disclosed. The fluid pump 200 can be similar, or identical, to any of the pumps disclosed in Appendix 1 and Appendix 2 to the ‘Related Application’ identified herein. As shown in FIGS. 2-4, the fluid pump 200 includes a pump body 202 with a suction connection 202a and a discharge connection 202b. As well, first and second pump heads 204 may be removably connected to the pump body 202 by way of threaded union nuts 206. The pump body 202 can be supported by a base 208.

With particular reference to FIG. 4, the fluid pump 200 further includes a pair of suction check valves 210, each of which includes a suction check ball 210a. Similarly, the discharge side of the fluid pump 200 includes a pair of discharge check valves 212, each of which includes a discharge check ball 212a. As will be apparent from FIG. 4, the suction check balls 210a are the same size as the discharge check balls 212a.

As suggested above, the fluid pump 200 disclosed in FIGS. 2-4 can implement various aspects of the embodiments disclosed herein in order to help avoid, or at least attenuate, some of the problems noted herein. For example, in one configuration, the suction connection 202a has a relatively larger flow area than the flow area of the discharge connection 202b. Correspondingly, in this example, the suction check valves 210 may be relatively larger than the discharge check valves 212. Particularly, the suction check balls 210a may each have a relatively larger outside diameter than the outside diameter of the discharge check balls 212a, and/or the flow area defined by the suction check valves 210 may be relatively larger than the flow area defined by the discharge check valves 212. Except for the aforementioned changes, the structure and operation of the modified fluid pump 200 may remain largely unchanged relative to the structure and operation of the unmodified fluid pump 200.

Directing attention finally to FIG. 5, details are provided concerning another embodiment of a fluid pump designated generally at 300. As in the case of other embodiments disclosed herein, and except as noted in the following discussion, the fluid pump 300 can be similar, or identical, to any of the pumps disclosed in Appendix 1 and Appendix 2 to the ‘Related Application’ identified herein. Thus, in one or more particular embodiments, the fluid pump 300 takes the form of an air operated double diaphragm (AODD) pump. As shown in FIG. 5, the fluid pump 300 includes a pump body 302 with a suction connection 302a and a discharge connection 302b. As well, first and second pump heads 304 may be removably connected to the pump body 302 by way of threaded union nuts 306. The pump body 302 can be supported by a base 308.

With continued reference to FIG. 5, the fluid pump 300 further includes a pair of suction check valves 310, each of which includes a suction check ball 310a. Similarly, the discharge side of the fluid pump 300 includes a pair of discharge check valves 312, each of which includes a discharge check ball 312a. Each of the suction check balls 310a is confined in, and configured for movement back and forth within, a respective suction check bore 314 so as to alternately allow, and prevent, fluid flow through the suction check bore 314. Similarly, each of the discharge check balls 312a is confined in, and configured for movement back and forth within, a respective discharge check bore 316 so as to alternately allow, and prevent, fluid flow through the discharge check bore 316.

As further indicated in FIG. 5, a sealing element 318 is disposed within each of the suction check bores 314. In at least some embodiments, the sealing elements 318 each take the form of an O-ring. As well, a sealing element 320 is disposed within each of the discharge check bores 316. Like the sealing elements 318, the sealing elements 320 may each take the form of an O-ring. The sealing elements 318 and 320 can be made of PTFE and/or any other suitable material(s). In operation, the sealing elements 318 and 320 each cooperate with a respective corresponding check ball 310a and 312a to prevent flow through the discharge check bore 316 in which the check ball 310a or 312a is situated. More specifically, when the check ball 310a or 312a is seated against a corresponding sealing element 318 or 320, flow through the corresponding check bore 316 or 314 is prevented.

With continuing reference to FIG. 5, and in view of the discussion above, it will be apparent that the suction check valves 310 of the fluid pump 300 are larger than the discharge check valves 312. In particular, the suction check bores 314 have a relatively larger inside diameter than the inside diameter of the discharge check bores 316. Likewise, the suction check balls 310a have a relatively larger outside diameter than the outside diameter of the discharge check balls 312a. Put another way, there is a size differentiation between the suction check valves 310 and the discharge check valves 312. Correspondingly, the inlet bore 322 of the fluid pump 300 is relatively larger than the outlet bore 324 of the fluid pump 300. That is, in the example of FIG. 5, the inside diameter of the inlet bore 322 is larger than the inside diameter of the outlet bore 324. It should be noted that although the inlet bore 322 is larger than the outlet bore 324, the threaded suction connection 302a and the threaded discharge connection 302b indicated in FIG. 5 may be the same size. As discussed below, the size differentiation between the suction and discharge sides of the fluid pump 300 may be advantageous in a variety of ways.

For example, the relatively large size of the inlet bore 322, suction check valves 310 and suction check bores 314 is associated with a relatively smaller pressure drop through those elements and, correspondingly, contributes to an overall relative reduction in pressure loss on the suction side of the fluid pump 300. Thus, the Net Positive Suction Head required (NPSHr) for efficient fluid pump 300 operation is reduced. This reduction in pressure loss on the suction side of the fluid pump 300 contributes to a relative increase in the operational efficiency of the fluid pump 300. As well, the relatively larger sizes of the inlet bore 322, suction check valves 310 and suction check bores 314 may help to reduce the occurrence and/or severity of cavitation in the fluid pump 300. The size differentiation between the suction and discharge sides of the fluid pump 300 may also reduce the extent to which pulsation occurs in the fluid discharge stream of the fluid pump 300. As well, the size differentiation between the suction and discharge sides of the fluid pump 300 may enable a relative increase in the discharge flow rate of the fluid pump 300 relative to the discharge flow rate that would be achieved in the absence of such a size differentiation. In more detail, increased suction allows the fluid chambers to fill more completely which makes the pump more efficient. Thus, the pump can run at a slightly slower cycle rate for a specific flow rate. The slower cycle rate leads to fewer pulses over time which reduces pump wear and particle shed. The freer flowing inlet valves reduce the pressure differential of the incoming fluid. The reduction in pressure differential lowers the rate at which cavitation can occur. The reduction in cavitation also prolongs pump life and increases pump efficiency.

Although this disclosure has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this disclosure. Accordingly, the scope of the disclosure is intended to be defined only by the claims which follow.

Claims

1. A displacement pump, comprising: a suction side including a suction check valve; anda discharge side including a discharge check valve, the discharge side and suction side being configured for selective fluid communication with each other, and the suction check valve defining a flow area that is relatively larger than a flow area defined by the discharge check valve.

2. The displacement pump as recited in claim 1, wherein the displacement pump includes a displaceable element, and operation of the pump is effected by alternating movements of the displaceable element.

3. The displacement pump as recited in claim 1, wherein the displacement pump is an air-operated displacement pump.

4. The displacement pump as recited in claim 1, wherein the displacement pump is a diaphragm pump.

5. The displacement pump as recited in claim 1, wherein the displacement pump is a bellows pump.

6. The displacement pump as recited in claim 1, wherein the displacement pump is an air-operated double diaphragm (AODD) pump.

7. The displacement pump as recited in claim 1, wherein a flow area of the suction side is relatively larger than a flow area of the discharge side.

8. The displacement pump as recited in claim 1, wherein the suction check valve includes a suction check element, and the discharge check valve includes a discharge check element, and the discharge check element has an outside diameter that is smaller than an outside diameter of the suction check element.

9. The displacement pump as recited in claim 8, wherein one or both of the suction check element and the discharge check element is a ball.

10. A diaphragm pump, comprising: a suction side comprising an inlet bore configured for selective fluid communication with first and second suction check bores, each of the suction check bores housing a respective suction check ball, and each suction check bore and suction check ball forming part of a suction check valve; anda discharge side comprising an outlet bore configured for selective fluid communication with first and second discharge check bores, each of the discharge check bores housing a respective discharge check ball, and each discharge check bore and discharge check ball forming part of a discharge check valve,wherein the inlet bore has a larger flow area than a flow area of the outlet bore, the first and second suction check bores each have a relatively larger flow area than respective flow areas of the first and second discharge check bores, and the suction check balls are relatively larger in diameter than the discharge check balls.

11. The diaphragm pump as recited in claim 10, further comprising: a pump body;a pump head connected to the pump body; andfirst and second diaphragms disposed between the pump head and the pump body, and one side of one of the first and second diaphragms is arranged for fluid communication with one or the other of the suction side or the discharge side.

12. The diaphragm pump as recited in claim 11, wherein one or more of the following components substantially comprises plastic: the pump body, the pump head, the first diaphragm, the second diaphragm, the suction check valve, and the discharge check valve.

13. The diaphragm pump as recited in claim 11, further comprising a union nut that releasably secures the pump head to the pump body.

14. The diaphragm pump as recited in claim 10, wherein the diaphragm pump is an air-operated double diaphragm (AODD) pump.