DIAPHRAGM AND PISTON PUMP

Abstract: An improved double acting diaphragm pump utilizes at least one supplemental pressure chamber (26, 34), including a supplemental piston (24) and cylinder, arranged coaxially with the connecting shaft (60) of the two diaphragms (14, 16). The supplemental chambers (26, 34) are connected via parallel pressure lines or conduits (90, 91) to the pressure source for the two diaphragms (14, 16) and associated pressure chambers (64, 76).

Description: DIAPHRAGM AND PISTON PUMP BACKGROUND OF THE INVENTION This invention relates generally to an improved double acting diaphragm pump and, more particularly, to a double acting diaphragm pump wherein the pumping force upon the fluid which is to be pumped exceeds the force attributable to pneumatic or other fluid pressure directly on the diaphragm. Such pumps are often called 2:1, 3:1, etc. diaphragm pumps. Heretofore, a double acting diaphragm pump typically includes first and second, main diaphragms each of which separate a pump chamber from a pressure chamber. The pump chamber receives the fluid or material pumped or transported and the pressure chamber receives pressurized fluid such as air that acts upon the diaphragm to .effect flexure and thus pumping action. The separate diaphragms for a double acting diaphragm pump art} generally connected by a shaft so that the diaphragms will reciprocate in unison in a manner which alternately provides pumping of fluid from one of the pump chambers or the other. Since the two pump chambers are connected to a common inlet manifold and a common outlet manifold, a continuous flow of fluid into the inlet manifold and from the outlet manifold is provided by the described operation of the pump. The force to effect the pumping action by such a pump is equal to the area of the diaphragm times the pressure per unit of area of the diaphragm. Thus, in a double acting diaphragm pump which provides a continuous output, the pumping force is limited by the area of the main diaphragm. There has, therefore, been a need to enhance the pumping force. Heretofore, a known double acting diaphragm pump which provides for enhanced pumping force on fluid in the pumping chamber includes a separate fluid pressure diaphragm mechanically connected to a spaced main pumping diaphragm b\ a shaft. The separate fluid pressure diaphragm has a surface area which may be equal to or greater than the main pumping diaphragm thus providing an increased pumping force through the mechanical shaft connection to the main pumping diaphragm. U.S. Patent No. 4,830,586, assigned to the Aro Corporation, Bryan, Ohio (the assignee of this patent application) shows such a device. Nevertheless, there has remained a need to provide an improved diaphragm pump capable of providing enhanced pressure for pumping fluid and improved operating life particularly at higher operating pressure. SUMMARY OF THE INVENTION Briefly, the present invention relates to a double acting diaphragm pump of the type which includes a pair of flexible diaphragms interconnected by a shaft and operative to reciprocate in response to pressure on one or the other of the diaphragms to effect pumping through a first pumping chamber associated with one diaphragm and a second pumping chamber associated with the other diaphragm. Thereby a continuous fluid input and output is effected by the double acting diaphragm pump. The invention specifically relates to the improvement of a supplemental pressure chamber defined, in part, by a piston and cylinder which provides an additive pumping force to the main diaphragm via a connected shaft means. The additive force is synchronized with the force derived from pressure on the appropriate main diaphragm. Such synchronization is effected by means of a parallel fluid pressure conduit connection to the supplemental chamber and the pressure chamber. In this manner, additive force may be provided for each of the pumping chambers. Additional supplemental chambers connected in parallel in the manner described may provide further additive forces for pumping. Thus, it is an object of the present invention to provide an improved, double acting, diaphragm pump comprising at least one supplemental pressure housing including first and second supplemental fluid pressure chambers and a supplemental piston and cylinder, each of said first and second supplemental fluid pressure chambers having a wall thereof defined by said supplemental piston, said supplemental piston being connected to the shaft means for movement therewith; and fluid conduit means for connecting said source means with said second supplemental fluid pressure chamber in parallel with said first pumping chamber and for connecting said source means with said first supplemental fluid pressure chamber in parallel with said second pumping chamber, thereby effecting an additive pumping force associated with the supplemental piston and driving said shaft means for pumping by said first and second pumping chambers. The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross sectional view of an embodiment of the improved double acting diaphragm pump of the present invention. DETAILED DESCRIPTION The present invention is shown in a preferred embodiment in Fig. 1 and constitutes an improvement relative to the construction described in U.S. Patent No. 4,830,586. The present invention thus relates to a double acting diaphragm pump. As shown in Fig. 1, the double acting diaphragm pump of the invention includes an inlet manifold 20 and an outlet manifold 18, and thence into one of two pumping chambers 10 or 12. Fluid from the chambers 10 or 12 then flows into the outlet manifold 20 and subsequently through outlet 50. Fluid is pumped alternatively from pumping chamber 10 and from pumping chamber 12. In this manner fluid is continuously pumped from the inlet 44 through the outlet 50 as the fluid alternatively is pumped via chambers 10 and 12. As known to those of ordinary skill in the art, check valves 47. 49. 51 and 53 are provided at the entrance and exit of each chamber 10 and 12 to control the direction of fluid flow through the chambers 10 and 12 from the inlet manifold 18 to the outlet manifold 20 as the diaphragms 14 and 16 associated with the pumping chambers flex to effect fluid flow. The construction of each of the chambers 10 and 12 is substantially the same. Chamber 10 is formed, in part, by a housing 52, and a flexible diaphragm 14 which is a main diaphragm 14 that cooperates with housing 52. Diaphragm 14 is sandwiched between plates 56 and 58 which connects to a shaft 22. The shaft 22 reciprocates within a second housing 62. The second housing 62 and diaphragm 14 further define a pressure chamber 64. A fluid pressure conduit 66 connects from a pilot control valve assembly 28 to chamber 64 and provides high pressure fluid to the chamber 64 that acts against the surface area of the. diaphragm 14 causing operation or flexure of the diaphragm 14 and pumping of fluid through chamber 10. Alternately, conduit 66 connects to an exhaust as controlled by assembly 28. In a similar fashion, chamber 12 is defined by a housing 66 and a main flexible diaphragm 16. The diaphragm 16 is held between plates 70 and 72 which attach with the shaft 60. The shaft 60 is further retained within a housing 74 which defines a second pressure chamber 76. A fluid conduit 69 connects to the second pressure chamber 76 by way of the control mechanism 28. Conduit 69 may also connect to exhaust. The chambers 64 and 76 are alternatively pressurized and the diaphragms 14 and 16 alternatively flex in reciprocal fashion to cause fluid to flow into the chambers 10 and from the chambers 12 or vice versa. The operation and flow of pressure to the chambers 64 and 76 via conduits 66, 69 is effected by the control means 28. The improvement of the present invention constitutes the inclusion of supplemental pressure chambers 26 and 34 defined by the housing 62 and 74 in combination with an additional supplemental piston 24. Piston 24 separates the supplemental pressure chambers 34 and 26 and is generally coaxial with the chambers 10 and 12 and the shafts 60 and 22. Thus the supplemental piston 24 is sandwiched between shaft 60 and adapter 80. This assembly reciprocates in unison with the shaft 60. The direction of movement of the piston 24 within the supplemental pressure chambers 34 and 26 is determined by the pressure acting on piston 24 which, in turn, is a function of control means 28 and the connection thereof through appropriate conduits to chambers 34 and 26. Specifically, conduit 66 is in parallel relation with a conduit 90 to chamber 26 so that chamber 26 is pressurized simultaneously with chamber 64. In like fashion, the chamber 34 is connected in parallel via conduit 91 with the chamber 76. In this manner, the chambers 34 and 76 are simultaneously pressurized and the force of fluid pressure within those chambers 34 and 36 acts on the diaphragms 16 and through the shaft 60 against fluid within the chamber 12. If the piston 24 has a surface area exactly equal to that of the diaphragm 14. then the total force on the fluid within the chamber 10 is twice that of a typical prior art pump that does not include the piston 24, in other words, a typical double acting diaphragm pump. Similarly, the pressure on fluid within the chamber 12 would be doubled due to pressure in chambers 34 and 76. The piston 24 is thus typically circular and concentric with the shaft 60. The shaft 60 reciprocates back and forth and acts to transmit force and movement of the various diaphragms at each of the chambers 34, 76, 26 and 54 are alternately filled with pressurized air or fluid and connected to exhaust. Note that the surface area or effective surface area of the piston 24 may be of any desired size in order to control the additive force imparted to the shaft 60. For example, the area of the piston 24 may be twice that of the area of the diaphragm 14. Alternatively, the area of the piston 24 may be one half that of the area of the diaphragm 14. Also, a plurality of piston and cylinders providing supplemental pressure may be arranged along the axis of the shaft 60. That is, plurality of supplemental piston and cylinders and associated supplemental chambers may be arranged in parallel arrangement along the axis of the shaft 60, each of the supplemental chambers associated with a supplemental piston and cylinder being appropriately connected with a pressure source in parallel with the main pressure chamber to drive the shaft 60 and provide pressure to the appropriate pumping chamber. Other variations of the invention are possible. Thus, while there has been set forth a preferred embodiment of the invention, it is to be understood that the invention is to be limited only by the following claims and their equivalents.

Claims: What is claimed is: 1. In a double acting diaphragm pump of the type including first and second pumping chambers for alternately receiving and discharging a fluid which is to be pumped, said first and second pumping chambers having a wall thereof defined by first and second flexible main diaphragms, respectively, each of said first and second flexible main diaphragms having a surface for contact with said fluid, said first and second flexible main diaphragms also having another surface in communication with first and second pressure chambers, respectively, for receipt of a pressurized fluid to effect pumping, said pump further including source means for providing said pressurized fluid alternately to said first and second pressure chambers, said first and second flexible main diaphragms being mechanically connected by shaft means to thereby move in unison and reciprocate and alternately effect ingress and egress of said fluid to and from said first and second pumping chambers, the improvement ςomprising, in combination: at least one supplemental pressure housing including first and second supplemental motive pressurized fluid pressure chambers and a supplemental piston and cylinder, each of said first and second supplemental fluid pressure chambers having a wall thereof defined by said supplemental piston, said supplemental piston being connected to the shaft means for movement therewith; and fluid conduit means for connecting said source means with said second supplemental fluid pressure chamber in parallel with said first pumping chamber and for connecting said source means with said first supplemental fluid pressure chamber in parallel with said second pumping chamber, thereby effecting an additive pumping force associated with said supplemental piston and driving said shaft means for pumping by said first and second pumping chambers. 2. The improved double acting diaphragm pump of claim 1 wherein the areas of said first and second flexible main diaphragms and said supplemental piston are substantially equal to provide a pumping force which is substantialh double the force associated with said first and second flexible main diaphragms. 3. The improved double acting diaphragm pump of claim 1 wherein said supplemental piston has an area which is a selected multiple of the area of said first flexible main diaphragm to provide a selected pumping force.

Inventors: DE JONGHE WERNER, VAN DEN BERGH LOUIS, VERBERCKMOES GEORGES, DE JONGHE, WERNER, VAN DEN BERGH, LOUIS, VERBERCKMOES, GEORGES
Applicants: ARO CORP, THE ARO CORPORATION
Application year: 1992
Main classification: F04B43
IPC codes: F04B43