WO1999020898A2

WO1999020898A2 - Pumps and drive and valve assemblies useful in same

Info

Publication number: WO1999020898A2
Application number: PCT/US1998/022281
Authority: WO
Inventors: E. Dale Hartley; F. Scott Hartley
Original assignee: Shurflo Pump Manufacturing Co.
Priority date: 1997-10-22
Filing date: 1998-10-21
Publication date: 1999-04-29
Also published as: WO1999020898A3

Abstract

The present pumps include a housing, an inlet, an outlet, an inlet chamber, an outlet chamber, a pumping chamber, a pumping member and a drive. In one embodiment, a chamber diaphragm is provided which increases the fluid output capacity and/or reduces the fluid output pulsations of the pump. The present chamber diaphragms are particularly useful in combination with confined quantities of air which influence the movement of portions of the diaphragms. Drive assemblies are provided which enhance pump performance and/or load carrying capabilities. Valve assemblies are included which provide reliability, cost effectiveness and ease of assembly. The present pumps are straighforward, inexpensive to produce and assemble and are very effective and have long useful lives.

Description

PUMPS AND DRIVE AND VALVE ASSEMBLIES USEFUL IN SAME

Background of the Invention

The present invention relates to pumps and to drive and valve assemblies useful in such pumps. More particularly, the invention relates to positive displacement pumps, including but not limited to single pumping chamber pumps, to drive configurations useful in increasing load carrying capacities of such pumps and to diaphragms and valve assemblies useful in improving pump efficiency.

A great number of pumps have been known for use in pumping various fluids, in particular liquids. One such class of pumps are the positive displacement pumps, such as diaphragm pumps . Among these pumps are those which include a single pumping chamber and a single pumping member or piston. Pumps which include a single pumping chamber do have a number of drawbacks. For example, because only one pumping chamber and pumping member are included, flow inefficiencies are most noticed and the output flow of fluid from the pump is not steady, but rather occurs in pulses or surges. Pumps with multiple pumping chambers can also benefit from increased flow efficiencies .

It would be advantageous to provide pumps and drive configurations and valve assemblies for use in such pumps which address one or more of these concerns.

Summary of the Invention

New pumps, for example, including inlet and outlet chambers, and drive and valve assemblies useful in such pumps, have been discovered. The present pumps, including but not limited to, single cylinder pumps, which include separate inlet and outlet chambers, have been found to have increased capacities and/or more steady outputs, that is fluid outputs with reduced pulsations, relative to generally similar prior art pumps. In addition, the present pumps preferably includes drives which are straightforward, easy to assemble, cost effective, self aligning, and provide increased pumping load support and overall pump life. Moreover, the present valve assemblies are straightforward, reliable, and cost effective. In addition, the present pumps are relatively easy to assemble and preferably provide substantial pump manufacturing flexibility. For example, a substantial portion of the pump can be pre-assembled prior to incorporating the motor and other drive components. Thus, the pumps can be easily customized with the desired motor and drive components at the time of final assembly. Overall, the present pumps, drive configurations and valve assemblies are very cost effective, flexible and provide performance benefits relative to prior art devices.

The present pumps comprise a housing, preferably in two or more housing sections, defining an inlet and an outlet and partially defining a pumping chamber, an inlet chamber and an outlet chamber. The inlet leads through the inlet chamber to the pumping chamber, while the outlet leads from the pumping chamber through the outlet chamber. A pumping member is provided which is moveable in the pumping chamber on an intake stroke and on a discharge stroke. On the intake stroke, fluid from the inlet chamber is drawn into the pumping chamber, while on the discharge stroke fluid in the pumping chamber is discharged into the outlet chamber. Although two or more pumping chambers and/or two or more pumping members may be included the present pumps preferably include only one pumping chamber and only one pumping member. A drive is provided for moving the pumping member on the intake and discharge strokes.

In one useful embodiment of the present invention, a chamber diaphragm is provided and is positioned and adapted to seal the inlet chamber from the outlet chamber. This diaphragm partially defines both the inlet and outlet chambers, and preferably provides a sealable membrane between the inlet and outlet valves and the housing cover or lid that would have otherwise defined the upper portion of these chambers. In doing so, a trapped or sealed volume of air is created on assembly, by the chamber diaphragm, between the chamber diaphragm and the housing cover or lid. This has the effect of forming an accumulator which can separately store and release energy to the inlet chamber and/or outlet chamber, while only slightly affecting the external appearance of the pump, for example, by raising the housing cover or lid by the amount required to afford the trapped or sealed air space used.

The chamber diaphragm includes a dome structure partially defining the inlet chamber and/or an indent structure (an inverted dome structure) partially defining the outlet chamber. The dome structure has a dome configuration, and preferably extends outwardly away from the pumping chamber. The dome structure is adapted to at least partially collapse, preferably toward the pumping chamber, during the intake stroke and to move toward the original dome configuration during the discharge stroke. In doing so, an amount of energy is stored during the intake stroke by expanding the trapped air volume defined by the chamber diaphragm, and released back to the inlet chamber in the form of a negative pressure on the liquid in the inlet chamber during the discharge stroke of the pump. The effect of this action is to provide an additional amount of suction or negative pressure in the inlet chamber during the positive pumping phase or discharge stroke of the pump, thereby increasing the capacity or overall efficiency of the pumping cycle, as well as serving to smooth or reduce fluid output pulsations.

The indent or inverted dome structure partially defining the outlet chamber is preferably configured to extend inwardly toward the pumping chamber. This inverted dome structure is adapted to at least partially collapse, preferably away from the pumping chamber, during the discharge stroke, in effect expanding the outlet chamber, and to move toward the original configuration during the intake stroke. An amount of energy is stored by compressing the trapped air volume defined by the chamber diaphragm (the inverted dome structure of the chamber diaphragm) and housing during the discharge stroke. That energy is released back to the outlet chamber in the form of a positive pressure on the liquid in the outlet chamber during the intake stroke of the pump. The result of this is to supply an additional amount of positive pressure in the outlet chamber during the intake stroke of the pump, when the outlet valves are normally closed, thereby increasing the capacity or overall efficiency of the pump, as well as smoothing or reducing the inherent fluid output pulsations created by the pumping cycle.

The operation of the dome structure and/or indent structure increase fluid output flow rates and reduce the output fluid flow pulsations relative to a similar pump with a substantially planar chamber diaphragm. The dome structure and/or the indent structure can be considered to provide increased pumping action or force to the fluid being pumped so that the present pumps have increased efficiency relative to a similar pump without the dome structure and/or indent structure.

The present pumps can include one or both, preferably both, of the dome structure and the indent structure. In the event only the indent structure is employed, the indent structure preferably is not employed in controlling the one/off status of the pump. Thus, for example, the movement of the indent structure on the intake and/or discharge strokes preferably is not used to activate any on/off switch assembly, such as a pressure switch.

The drive of the pump preferably includes an eccentric member adapted to be operatively coupled to the pumping member and to the rotating shaft of a motor. Such coupling is effective to translate the rotational movement of the shaft into the movement of the pumping member on the intake and discharge strokes. In a particularly useful embodiment, the eccentric member is made from a powdered metal, for example, by molding or other conventional powdered metal processing. Such powdered metal eccentrics provide as good or better performance, and are substantially less expensive, relative to similarly configured eccentrics which are machined from solid metal.

In one embodiment, a new drive assembly has been found to increase the pumping load support and overall life of the pump, for example, by providing additional outboard support to the eccentric drive member. This drive assembly utilizes three (3) supports, each independently selected from bearings and bushings, on a single driven shaft. Each of these supports significantly benefits the pumping load support while not interfering with the alignment of the other supports on the driven shaft.

An outboard support is useful to increase the load carrying capacity of the pump, thereby increasing its performance and life. The three supports useful in the present drive assembly preferably include (1) the motor end bushing/bearing, (2) the pump piston bushing/bearing, and (3) the pump outboard bushing/bearing. It is important to allow each of the supports to act independently or individually and not interfere with the actions of the other supports, which can lead to increased friction or binding of the drive assembly of the pump. This is accomplished by allowing the eccentric member to float, or self-align, on the motor shaft, which allows the pumping loads to be distributed, preferably substantially evenly distributed, among the three supports. During assembly, the exact alignment of the outboard support is not critical to maintaining optimum performance of the drive assembly. The resulting configuration of the self -aligning eccentric member thus lends itself to simplifying the design and assembly of the pump, as well as assuring consistent and reliable operation over pumps without this feature.

One of the advantages of the present pumps is that either bearings or bushings can be used as the drive supports. Thus, depending on the application in which the pump is to be used, bearings or bushings can be incorporated during the final assembly process. In general, bearings are used for more severe applications. Conversely, bushings are used for less severe applications .

An important advantage of the present invention is that a substantial portion of the pumps can be pre- assembled without selecting which supports are to be used. At final assembly, when it is more clear which specific pump is to be produced, the choice of supports, as well as of the motor and eccentric member, can be rapidly made and implemented. The pre-assembly feature of the present invention is more effective if the pre- assembled portions of the pumps are sized and adapted to be employed with either bearings or bushings. Preferably, the bearings and bushings to be employed in a pump are sized so as to be interchangeable in the pre- assembled portions of the present pumps. The present pumps preferably include at least one inlet valve positioned and adapted to control the flow of fluid between the inlet chamber and the pumping chamber, and at least one outlet valve positioned and adapted to control the flow of fluid between the pumping chamber and the outlet chamber. The inlet valves and outlet valves preferably include valve elements which are substantially circular perpendicular to the general direction of fluid flow to and from the pumping chamber. The inlet and outlet valve elements preferably have substantially identical configurations. The present pumps include two inlet valves and two outlet valves .

The flow capacity of the pump is effectively enhanced by placing two circular valves, which have substantial flexural and sealing characteristics, in an asymmetrical inlet and outlet chamber, relative to a similar chamber with the largest single circular valve in place. By maintaining an identical layout for both inlet and outlet valve assemblies, a cost effective, reliable, easy to assemble and more efficient performing valving system is provided.

In a particularly useful embodiment, the housing defines an inlet valve seat and the inlet valve includes an inlet valve element coupled to an inlet valve retainer which is secured to the housing. The inlet valve retainer is positioned to be effective to maintain the inlet valve element in place relative to the inlet valve seat. The housing preferably defines an outlet valve seat. The outlet valve includes an outlet valve element coupled to an outlet valve retainer secured to the housing. The outlet valve retainer is positioned to be effective to retain the outlet valve element in place relative to the outlet valve seat.

The present valve assemblies, which are useful in present pumps, include a housing element, a valve element and a retainer member. The housing element includes a valve seat, which defines at least one through opening, and preferably a plurality of through openings, for fluid flow. The valve element is operatively coupled to the valve seat and is moveable between an open position in which fluid is allowed to flow through the through opening or openings and a closed position is which fluid is prevented from flowing through the opening or openings . The retainer member is secured to both the housing element and the element and is positioned to retain the valve element in place relative to the valve seat.

Preferably, the valve assembly includes two of the valve seats and two of the valve elements. The retainer member is secured both to the housing element and the valve elements to retain the valve elements in place relative to the valve seats.

In one very useful embodiment, the valve seat includes a centrally located aperture and the valve element includes a centrally located first peg extending outwardly from the valve element body in the general direction of fluid flow across the valve. This first peg is sized and adapted to be received and held, e.g., utilizing a friction or interference fit, in the aperture of the valve seat to assist in coupling the valve element to the valve seat . The valve element preferably includes a centrally located second peg extending outwardly away from the valve element body in an opposing direction relative to the first peg. The housing element includes at least one housing aperture and the retainer member includes an indent and a retainer projection. The second peg is located at least partially in the indent and the retainer projection is fit, e.g., friction or interference fit, in the housing aperture. In this manner, the valve element is very conveniently retained in place relative to the valve seat.

One important advantage of the present valve assemblies is that the valve elements and retainer members preferably can be interchangeably used in either inlet valves or outlet valves in accordance with the present invention. This commonality of construction reduces the cost of manufacturing and assembling. The various features of this invention can be used singly or in any combination. Thus, all such features and combinations are included within the scope of the present invention.

The invention, together with additional features and advantageous thereof, may best be understood with reference to the following description taken in connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross sectional view of a pump in accordance with the present invention with a pumping member on the intake stroke.

Fig. 2 is a cross sectional view of the pump shown in Fig. 1 with the pumping member on the discharge stroke . Fig. 3 is a cross sectional view taken generally along line 3-3 of Fig. 2.

Fig. 4 is an exploded view, partly in cross section, of a portion of the pump shown in Fig. 1.

Fig. 5 is a view partially in cross section of an alternate embodiment of a pump in accordance with the present invention.

Fig. 6 is a plan view taken generally along line 6- 6 of Figure 2.

Fig. 7 is an exploded view showing a valve assembly in accordance with the present invention.

Fig. 8 is a cross sectional view taken generally along line 8-8 of Fig. 7.

Fig. 9 is a prospective view of the chamber diaphragm included in the pump shown in Fig. 1. Fig. 10 is a prospective view of an alternate embodiment of a chamber diaphragm.

Fig. 11 is a cross sectional view taken generally along line 11-11 of Fig. 10.

Detailed Description of the Drawings

Referring now to Figs. 1 to 5 , a pump in accordance with the present invention, shown generally at 10, includes a housing 12, a chamber diaphragm 14, an inlet 16, an inlet chamber 18, inlet valves 20, a pumping chamber 22, a pumping member 24, a sealing diaphragm 26, a piston extension 28, a piston bushing 30, outboard bushing 31, an eccentric 32, a motor shaft 34, a motor 36, a motor bushing 37, outlet valves 38, outlet chamber 40 and outlet 42. The housing 12 includes three (3) housing sections, a first housing section 44, a second housing section 46 and a third housing section 48, all of which are secured together with four (4) conventional screw-type fasteners 50. The housing 12 partially defines the inlet chamber 18 and outlet chamber 40, as well as inlet 16 and outlet 42. In addition, housing 12 partially defines pumping chamber 22.

Chamber diaphragm 14 is secured in a sealed relationship to housing 12, in particular between first housing section 44 and second housing section 46. Chamber diaphragm 14 acts to seal inlet chamber 18 from outlet chamber 40. In addition, chamber diaphragm 14 includes a dome structure 52 having a dome configuration as shown in Fig. 2, and an inverted dome or indent structure 54 having an indent configuration as shown in Fig. 1. The air spaces 56 and 58 above dome structure 52 and indent structure 54, respectively, are sealed or trapped. That is, the air in each of these spaces 56 and 58 is sealingly confined to such space. The chamber diaphragm 14, shown also in Fig. 9, includes a peripheral seal portion 84 which, when in pump 10, is placed between first housing section 44 and second housing section 46. A sealing region 86 extends across the chamber diaphragm 14 and acts, when the chamber diaphragm is in place in pump 10, to seal the inlet chamber from the outlet chamber. Sealing region 86 is located and secured to both first housing section 44 and second housing section 46. Chamber diaphragm 14, as well as sealing diaphragm 26, should be made of a sufficiently flexible material to provide the desired sealing functions described herein. In a particularly useful embodiment, such diaphragms are made of polymeric materials, with the polymeric material sold under the trademark Santoprene being especially useful . Such polymeric materials should be chosen, particularly with regard to the chamber diaphragm 14 to be effective to provide the pumping benefits described herein. With particular reference to Figs. 1 and 2, the dome structure 52 of chamber diaphragm 14 is adapted to at least partially collapse toward the pumping chamber during the intake stroke (Fig. 1) and to move toward the original dome configuration during the discharge stroke (Fig. 2) . This back and forth movement of dome structure 52 provides an amount of energy to be stored during the intake stroke by expanding the volume of the trapped air in space 56, and releasing such energy back into the inlet chamber 18 in the form of a negative pressure on the liquid in the inlet chamber during the discharge stroke of pump 10. The effect of this action is to provide additional suction or negative pressure in the inlet chamber 18 during the discharge stroke of the pump 10. Ultimately, this increases the flow rate capacity or overall efficiency of the pump 10, and, in addition, acts to smooth out or mitigate against fluid output pulsations. The inverted dome structure or indent structure 54 in the outlet chamber 40 is adapted to at least partially collapse away from the pumping chamber 22 during the discharge stroke. In effect, this movement expands the outlet chamber 40. During the intake stroke the indent structure 54 moves toward its original configuration. Energy is stored by compressing the trapped gas in space 58 during the discharge stroke. This energy is released back into the outlet chamber 40 in the form of a positive pressure on the liquid in the outlet chamber during the intake stroke of the pump 10. The ultimate result of this energy being stored and then released is to supply an additional amount of positive pressure in the outlet chamber 40 during the intake stroke of the pump 10, thereby increasing the flow rate capacity or overall efficiency of the pump as well as smoothing out or reducing the fluid outlet pulsations of the pump .

The inlet valves 20 and outlet valves 38 are substantially identically configured, as will be discussed hereinafter. By maintaining an identical layout for both the inlet and outlet valve assemblies, benefits, for example, in terms of cost effectiveness, ease of assembly, reliability and performance effectiveness, are achieved. The inlet valves 20 control the flow of the fluid, preferably liquid, to be pumped from outlet chamber 18 into pumping chamber 22. Conversely, the outlet valves 38 control the flow of fluid from the pumping chamber 22 into the outlet chamber 40.

The sealing diaphragm 26 is sealingly secured to the housing 12, in particular between second housing section 46 and third housing section 48. Sealing diaphragm 26 is positioned between pumping member 24 and the top portion 58 of piston extension 28. Pumping member 24 includes a centrally located projection 60, while piston extension 28 includes a recess 62 which is adapted to receive and hold the projection 60. The recess 62 includes a shoulder 64 while the end 66 of projection 64 has a larger cross-section then the remainder of the projection. This feature allows the pumping member 26 to be snap-fit to the piston extension 28, as shown in Figs. 1 to 4.

In the pump 10 shown in Figs. 1 to 4, a metal, for example, sintered bronze, piston bushing 30 is located inside the cylindrically shaped opening 68 of piston extension 28. The eccentric 32, preferably made of powdered metal, which is of substantially greater particulate hardness relative to the bushings, is located in the space defined by the piston bushing 30 and extends from both sides of this space. A metal, for example, sintered bronze, outboard bushing 31 is secured to fourth housing section 78. When assembled, the outboard bushing 31 receives the forward end portion 69 of eccentric 32 and acts as a support for the eccentric. Motor shaft 34, including a flat region 70 is coupled to the eccentric 32. Thus, the rotation of the motor shaft 34 causes the eccentric to rotate. Motor 36 includes a motor bushing 37, for example, made of sintered bronze, which acts to support the rotating shaf 34. A spacer 71 is provided between motor bushing 37 and eccentric 32 and rotates with the eccentric.

The eccentric 32 and shaft 34 are supported by outboard bushing 31, piston bushing 30 and motor bushing 37, each of which acts independently, without interfering with the actions of the other supports. The eccentric 32 is allowed to float relative to shaft 34. This, in effect, makes the drive assembly self-aligning and substantially evenly distributes the pumping load among the three supports. The pump 10 is provided with increased load carrying capability and/or a longer effective or useful life while, at the same time, being cost effective and easy to assemble. As the rotation of the shaft 34 and eccentric 32 occurs, the piston extension 28 and pumping member 22 are moved in a generally up and down direction as shown in Figs . 1 and 2 so that the pumping member can move on the discharge stroke and on the intake stroke.

One important advantage of the present pumps, for example, pump 10, is that substantially the entire pump except for the bushings 30 and 31, eccentric 32, motor shaft 34 and motor 36 can be pre-assembled. At the final assembly stage, when it is known which specific drive components are to be included in the pump 10, these drive components, that is bushings 30 and 31, eccentric 32, motor shaft 34 and motor 36 (and motor bushing 37) can be quickly and easily incorporated into the pump to provide the final product.

With particular reference to Fig. 4, the final assembly process preferably occurs by combining the pre- assembled portion 72 of pump 10 with motor 36 (including motor bushing 31 and motor shaft 31) . The piston bushing 30 is placed within the cylindrical space 68, defined by piston extension 28. The spacer 71 and eccentric 32 are then placed on the motor shaft 34. The motor 36 (and eccentric 32) is coupled to the housing 12 using conventional fasteners 82, shown in shadow in Fig. 3. The outboard bushing 31 and fourth housing section 78 are fastened to the third housing section 48 using three (3) conventional screw-type fasteners 80. During assembly, the exact alignment of the outboard bearing 31 is not critical to maintain effective performance. The configuration described provides a self-aligning drive assembly which is straightforward in design and relatively easy to assemble .

The inlet valves 20 and outlet valves 38 are shown in more detail with reference to Figs. 6 to 8. Specifically, the inlet valves 20 include valve elements 90 which have a generally circular configuration in the general flow from the inlet chamber to the pumping chamber. Similarly, the outlet valves 38 include valve elements 90 which are configured identically to the valve elements 90 of inlet valves 20. The valve elements 90 are preferably made of polymer material, with the polymeric material sold under the trademark Santoprene being particularly useful. The second housing section 46 includes outlet valve seats 92 and identically constructed inlet valve seats 92 for the inlet valves 20. An inlet valve retainer 94 is shown in Fig. 6. An identically constructed outlet valve retainer 94 is hidden from view in Fig. 6.

The basic construction of the intake and outlet valves 20 and 38 is shown in Fig. 7. Fig. 7 will be described with reference to the inlet valves 20. However, it should be understood that the outlet valves are identically constructed with the valve elements and valve retainer being located on the opposite side of the valve seats . With reference to Fig. 7, the valve seats 92 are located in the second housing section 46. Each of the valve seats 92 include a plurality of through openings 96 which allow liquid to pass through the valve seat when the valve elements 90 are open. The valve elements 90 include a centrally located first peg 98 which extends away from the body of the valve element in one direction, and a centrally located second peg 100 (which is structured identically to first peg 98) which extends away from the body of valve element in the opposite direction. Second housing section 46 includes two (2) spaced apart through openings 102. Valve retainer 94 includes two (2) spaced apart regions 104 which include indents 106. The valve seats 92 include centrally located openings 108 which are sized and adapted to receive, the second pegs 100 of valve elements 90 therein. The valve retainer 94 includes two (2) spaced apart projections 110 which are sized and adapted to fit, for example, interference or friction fit, into the openings 102 in second housing section 46. Thus, the valves are assembled by placing the second pegs 100 of valve elements 90 into the openings 108 of second housing section 46 and then placing the valve retainer 94 so that portions of the first pegs 98 are received in the indents 106 and the projections 110 are placed in the openings 102 of the second housing section. This assembly provides effective inlet valves while, at the same time, retaining the valve elements in place relative to the valve seat using the valve retainer.

The ability to use the same valve elements and valve retainers for both inlet valves and outlet valves is a substantial advantage in terms of reducing the number of parts required for pump 10 and, in addition, enhancing the ease of assembly.

In the configuration shown, having a combination of two (2) inlet valves and two (2) outlet valves with each of the valve elements 90 having a substantially circular configuration relative to the general flow of fluid across the valves is a substantial advantage in terms of flow rate and flow mechanics. Pump 10 functions as follows, particularly with reference to Figs. 1 and 2. During the intake stroke of the pumping member 24, the intake valves open and liquid to be pumped is passed from the inlet chamber 18 and inlet 16 across inlet valves 20 into the pumping chamber 22. During this stroke, the dome structure 52 of chamber diaphragm 14 partially collapses.

After the pumping member 24 has completed its intake stroke, it proceeds on a discharge stroke. This action is shown in Fig. 2. During the discharge stroke, the inlet valves close and the outlet valves open. The dome structure 52 moves towards its original dome configuration and the outlet chamber 15 is filled with liquid from inlet 16 for the next intake stroke.

During the discharge stroke, the outlet valves 38 open to allow liquid from the pumping chamber 22 to pass into outlet chamber 40 and through outlet 42 to be discharged from the pump 10. During the discharge stoke, the indent structure 54 moves away from pumping chamber 22, as shown in Fig. 2, thereby expanding the outlet chamber 40. The benefits described herein with regard to the dome structure 52 and indent structure 54 are relative to a similar pump in which the chamber diaphragm is substantially planar.

The present pump 10 with the dome structure 52 and indent structure 54, as described herein, has increased pumping capacity and provides for more steady state

(less flow pulsations) fluid output relative to a similar pump having a substantially planar chamber diaphragm. Fig. 5 illustrates an alternate pump, shown at 210. Except as expressly stated herein, this pump has a similar structure to pump 10. Parts of pump 210 which correspond to parts of pump 10 have the same reference numeral increased by 200. The primary difference between pump 210 and pump 10 is the use of bearings to enhance the rotation of eccentric 32. Specifically, a bearing 112 is located in cylindrical opening 268 between the piston extension 228 and the eccentric 232. In addition, a ball bearing 114 is used in place of bushing 76.

The use of bearings to facilitate rotation of the eccentric provides a pump which is effective in severe applications requiring high pumping capacity and/or involving high pumping loads. The pre-assembly feature noted herein is particularly useful with regard to choosing whether to use bushings and/or bearings in the present pumps. Thus, for example, if a similar pump is to be used in two applications, of differing requirements, the choice of whether to use bushings or bearings can be postponed until final assembly. This reduces manufacturing costs while, at the same time providing a very effective pump which has been "customized" to a particular application.

A further alternative involves a chamber diaphragm as shown in Figs. 10 and 11. The chamber diaphragm 314 has substantially the same configuration as chamber diaphragm 14 except as expressly described. Components of chamber diaphragm 314 which correspond to components of chamber diaphragm 14 are identified by the same reference numerals increased by 300.

The primary difference between chamber diaphragm 314 and chamber diaphragm 14 involves the removal of the indent structure 32 and the inclusion of an indent region 120. Indent region 120 is relatively smaller than the indent structure 52.

Chamber diaphragm 314 is particularly effective in combination with a pump having a pressure switch.

When the chamber diaphragm 314 is in place in the pump, similar to pump 10, the air space above the indent region 120 is open or vented so that the gases within that space are not confined. When excessive pressure is present in the outlet chamber, the indent region moves to a sufficient extent to cause the pressure switch to deactivate the pump.

It should be noted that the dome region 352 of chamber diaphragm 314 functions in a manner substantially similar to the dome structure 52 of pump 10, described previously. The air space above dome region 352 is confined. In other words, the pump with pressure switch 122 and chamber diaphragm 314 provides increased flow rates and relatively less fluid output pulsations relative to a similar pump having a chamber diaphragm with a planar region. While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A pump comprising: a housing defining an inlet and an outlet, and partially defining a pumping chamber, an inlet chamber and an outlet chamber, the inlet leading through the inlet chamber to the pumping chamber, the outlet leading from the pumping chamber through the outlet chamber; a pumping member movable in the pumping chamber on an intake stroke whereby fluid from the inlet chamber is drawn into the pumping chamber and on a discharge stroke whereby fluid in the pumping chamber is discharged into the outlet chamber ; a chamber diaphragm partially defining the inlet chamber and the outlet chamber and positioned and adapted to seal the inlet chamber from the outlet chamber, the chamber diaphragm including a dome structure partially defining the inlet chamber, the dome structure having a dome configuration and being adapted to at least partially collapse during the intake stroke and to move toward the dome configuration during the discharge stroke; and a drive for moving the pumping member on the intake and discharge strokes.

2. The pump of claim 1 which includes a first sealed chamber partially defined by the dome structure and containing a confined gas effective to provide a driving force to facilitate at least partially collapsing the dome structure.

3. The pump of claim 1 wherein the chamber diaphragm includes an indent structure partially defining the outlet chamber, the indent structure having an indent configuration and being adapted to move so as to expand the outlet chamber during the discharge stroke and to move toward the indent configuration during the intake stroke.

4. The pump of claim 3 which includes a second sealed chamber partially defined by the indent structure and containing a confined gas effective to provide a driving force to facilitate moving the indent structure toward the indent configuration.

5. The pump of claim 1 wherein the drive includes an eccentric member adapted to be operatively coupled to the pumping member and to the rotating shaft of a motor to translate the rotational movement of the shaft into the movement of the pumping member on the intake and discharge strokes.

6. The pump of claim 5 wherein the eccentric member is made from powdered metal .

7. The pump of claim 5 which further comprises a first support member carried by the housing, a second support member carried by the pumping member and a third support member carried by the motor, each of the first, second and third support members acting independently to increase the load carrying capability of the pump, the first second and third support members being independently selected from the group consisting of bearings and bushings .

8. The pump of claim 1 which further comprises at least one inlet valve positioned and adapted to control the flow of fluid between the inlet chamber and the pumping chamber, and at least one outlet valve positioned and adapted to control the flow of fluid between the pumping chamber and the outlet chamber.

9. The pump of claim 8 wherein the inlet valve and the outlet valve include valve elements which are substantially circular perpendicular to the general direction of fluid flow across the valve.

10. The pump of claim 8 which includes two inlet valves and two outlet valves, and the inlet valve elements and the outlet valve elements have substantially identical configurations.

11. The pump of claim 1 which includes only one pumping chamber and only one pumping member.

12. The pump of claim 1 wherein the chamber diaphragm includes an indent region adapted to move so as to expand the outlet chamber in response to excessive pressure in the outlet chamber, the movement being effective to activate a pressure switch.

13. A pump comprising: a housing defining an inlet and an outlet, and partially defining a pumping chamber, an inlet chamber and an outlet chamber, the inlet leading through the inlet chamber to the pumping chamber, the outlet leading from the pumping chamber through the outlet chamber; a pumping member movable in the pumping chamber on an intake stroke whereby fluid from the inlet chamber is drawn into the pumping chamber and on a discharge stroke whereby fluid in the pumping chamber is discharged into the outlet chamber; a chamber diaphragm partially defining the inlet chamber and the outlet chamber and positioned and adapted to seal the inlet chamber from the outlet chamber, the chamber diaphragm including an indent structure partially defining the outlet chamber, the indent structure having an indent configuration and being adapted to move so as to expand the outlet chamber during the discharge stroke and to move toward the indent configuration during the intake stroke; a sealed chamber partially defined by the indent structure and containing a confined gas effective to provide a driving force to facilitate moving the indent structure toward the indent configuration; and a drive for moving the pumping member on the intake and discharge strokes.

14. A pump comprising: a housing defining an inlet and an outlet, and partially defining a pumping chamber, an inlet chamber and an outlet chamber, the inlet leading through the inlet chamber to the pumping chamber, the outlet leading from the pumping chamber through the outlet chamber; a pumping member movable in the pumping chamber on an intake stroke whereby fluid from the inlet chamber is drawn into the pumping chamber and on a discharge stroke whereby fluid in the pumping chamber is discharged into the outlet chamber; and a drive for moving the pumping member on the intake and discharge strokes, the drive including a motor having a rotating shaft, an eccentric member operatively coupled to the pumping member and to the rotating shaft to translate the rotational movement of the shaft into the movement of the pumping member on the intake and discharge strokes, a first support member carried by the housing, a second support member carried by the pumping member and a third support member carried by the motor, each of the first, second and third support members operatively coupled to the eccentric member and acting independently to increase the load carrying capability of the pump.

15. The pump of claim 14 each of said first, second and third support members is independently selected from the group consisting of bearings and bushings .

16. The pump of claim 14 wherein the coupling of the eccentric member to the shaft is such to allow sufficient movement of the eccentric member relative to the shaft to self-align the eccentric member on the motor shaft, thereby distributing the load on the pump among the first, second and third support members.

17. A valve assembly comprising: a housing element including a valve seat, the valve seat defining at least one through opening for fluid flow; a valve element operatively coupled to the valve seat and being movable between an open position in which fluid is allowed to flow through the at least one through opening and a closed position in which fluid is prevented from flowing through the at least one through opening; and a retainer member secured to both the housing element and the valve element to retain the valve element in place relative to the valve seat.

18. The valve assembly of claim 17 which includes two of the valve seats and two of the valve elements, and the retainer member is secured to both the housing element and the valve elements to retain the valve elements in place relative to the valve seats .

19. The valve assembly of claim 17 wherein the valve element has a substantially circular configuration generally perpendicular to the direction of fluid flow.

20. The valve assembly of claim 17 wherein the valve seat includes a centrally located aperture and the valve element includes a centrally located first peg extending outwardly in the direction of fluid flow, the first peg being sized and adapted to fit into the aperture to assist in coupling the valve element to the valve seat.

21. The valve assembly of claim 20 wherein the valve element includes a centrally located second peg extending outwardly away from the first peg, the housing element includes at least one housing aperture, and the retainer member includes an indent and a retainer projection, the second peg being located at least partially in the indent and the retainer projection being located in the housing aperture.