US2871795A - Double acting diaphragm pump - Google Patents

Description

2 Sheets-Sheet 1 F. R. SMITH DOUBLE ACTING DIAPHRAGM PUMP;

Feb. 3, 1959 Filed Fab. 29, 1956 I I I'll Feb. 3, 1959 F. R. SMITH DOUBLE ACTING DIAPHRAGM PUMP 2 Sheets-Sheet 2 Fil ed Feb. 29, 1956 United States Patent O DOUBLE ACTING DIAPHRAGM PUMP Frederick R. Smith, Nitro, W. Va., assignor to American Viscose Corporation, Philadelphia, Pa., a corporation of Delaware Application February 29, 1956, Serial No. 568,522

13 Claims. 01. 103-150 The invention relates to pumps, and particularly to double acting diaphragm pumps.

An object of the invention is to provide a generally improved and more satisfactory double acting diaphragm pump.

Another object is the provision of a pump of small physical dimensions which is simple in construction and operation and employs a minimum of moving parts which are not subject to rapid wear or corrosion.

Still another object is to provide a pump, particularly suited for use with sensitive instruments such as laboratory test equipment, which is capable of delivering small amounts of fluid at a relatively accurate rate.

A further object is the provision of a double acting diaphragm pump in which the diaphragm actuating lever is enclosed within and forms a part of the diaphragm itself, and the fluid flow control means include resilient flap valves.

A still further object is to provide a pump formed of a series of parts secured in juxtaposed relationship for ease of manufacture, assembly, and repair.

These and other objects and advantages of the inven- I tion will be apparent from the following description and accompanying drawing in which:

Figure l is a perspective view illustrating part of the structure in an exploded position, and with a portion thereof being broken away;

Figure 2 is a front view of structure shown in Figure 1 in its assembled position;

Figure 3 is a left side view of the assembled structure shown in Figure 2;

Figure 4 is a fragmentary detail illustrating the operation of one of the pump flap valves; and

Figure 5 is a view similar to Figure 3 illustrating a modified form of diaphragm actuating lever.

In general, the invention relates to a double acting diaphragm pump formed of a plurality of parts individually fabricated and then secured together in juxtaposed relationship. The diaphragm actuating lever is enclosed within and forms a part of the diaphragm itself, and extends outwardly of the pump body where it is accessible for reciprocating movement. rial are employed to control the rate and direction of fluid flow. The pump has particular utility with test instruments where relatively small and accurate fluid delivery rates are desired, and the various parts maybe formed of inert materials when use of the pump with corrosive fluids is anticipated. a

The pump of the present invention is formed of a plurality of blocks or plates and sheets disposed in juxtaposed position and secured together to form an integral unit which is, in effect, two independent pump units actuated by a single diaphragm interposed therebetween. The corresponding parts on opposite sides of the diaphragm are mirror images of each other, and for the sake of clarity and simplicity, the description will be in general limited to the diaphragm and the parts to one side thereof, it being understood that parts on the opposite Flap valves of resilient mateto flow only toward the pump chamber.

2,871,795 Patented Feb. 3, 1959 "ice ' 2 side of the diaphragm are of the same construction as those parts which are described hereinafter.

With reference to Figures 1-4 of the drawing, the diaphragm 7 is formed of two sheets of flexible material 9' posed therebetween, while the remaining portion of the.

actuating lever 13 projects outwardly from the edge of the diaphragm in an accessible position for reciprocation as hereinafter described. As best seen in Figures 1 and 3, the end of the actuating lever interposed between the sheets 9 and 11 is formed into a ring 15 which is positioned approximately centrally of the diaphragm so that the force exerted by reciprocating the actuating lever is transferred to and distributed along a substantial area of the diaphragm. Against opposite faces of the diaphragm 7 are disposed the chamber blocks 17, each having its central portion formed with a circular opening 19 which serves as a pump chamber. The edges of the chamber blocks 17, adjacent the projecting portion of the actuating lever 13, are each formed with a tapered recess 21 which gradually decreases in dimension as it approaches the central opening 19. As shown in Figure l, the recesses 21 terminate before reaching the central opening 19 in the chamber blocks, and thus the segments 23 of the chamber blocks located between the central openings 19 and the innermost ends of the recesses 21 together serve as a fulcrum for the actuating lever 13.

Continuing the description'in relation to one of the pump units, against the face of the chamber block 17, opposite the diaphragm 7, is positioned a rectangular block 25, which for convenience may be called a fluid passage block. The top edge of the block 25 is formed with an outlet port 27 and an inlet port 29 which connect, respectively, with 'the angulated outlet passage 31 and the inlet passage 33, both of which open on the face of the block 25 remote from the chamber block 17. An outlet channel 35 passes transversely and angularly through the block 25 with its lowermost end opening into the pump chamber opening 19. This channel allows gas bubbles to escape from the pump chamber and also serves as a means for discharging the fluid therefrom. Delivery of fiuid into the pump chamber is accomplished through an inlet channel 37 passing transversely through the block 25 and opening into the pump chamber 19 as best seen in Figure 2.

Control of the rate and direction of fluid flow is accomplished by flap valves formed by means of a flexible and resilient sheet 39, preferably of rubber. The sheet 39 is disposed against the outermost face of the block 25 and is provided with two semi-circular openings 41 and 43 which are, respectively, in alignment with the outlet passage 31 and the inlet channel 37. The portion directly below the opening 41 serves as a flap valve 45 which covers the end of the outlet channel 35 and prevents the passage of fluid therein while allowing fluid to freely flow therefrom. In a similar manner, the portion directly opposite the opening 43 serves as a flap valve 47 which covers the end of the inlet passage 33 so as to allow fluid A valve plate 49 is disposed against the sheet 39 and is provided with a pair of circular openings 51 and 53, which are in align ment with the openings 41 and 43 formed in the sheet 39 and provide an area Within which the resilient portions 45 and 47 of the sheet 39 can flex as hereinafter described. An end plate 55 is disposed against the face of the valve plate 49 and serves to close the openings 51 and 53. It is of course understood that the plate 49 may be of sufficient thickness so that the openings 51 and 53 may extend partially into the plate 49 and thus be closed at the end opposite the sheet 39. In this manner the end plate 55 may be entirely eliminated.

The various parts described above are assembled as shown-in Figure land may-{be secured together by means of elongated screws 57 passing through suitableopenings 61 formed in the various parts and flxedin place 'by nuts 59, or maybe adhesively bonded together for ease of .construction.

As with conventionaldiaphragm pumps, the reciprocation of the actuating lever causes the diaphragm to induce a suction force anda pressure force in each of the pump chambers in an alternating relationship. Further, in a double acting diaphragm pump, the-suction and pressure forces in the .two individual pump units are also in alternate timed relationship .since the movement of the diaphragm in one direction creates .a suction force in one pump unit and a pressure force .in the other of the pump units, while a movement-.ofthe diaphragm in the opposite direction reverses the forces .induced in the respective pump units. Thus in operation, fluid is admitted through the inlet port 29 and passes into the inlet passage 33 where its flow is obstructed by .the resilient flap valve 47 of the sheet 39. As the actuating lever 13 is reciprocated in a horizontal direction, the suction created with each reciprocating stroke of the lever 13 causes the flap valves 47 of the respective pump units to be flexed away from the ends of the inlet passages 33 in an alternate relationship'so as to allow the fluid to pass through the inlet channels 37 and finally into the pump chambers 19. Any gas bubbles contained in the fluid rise to the top of the chamber 19 and are free to escape into the outlet channel 35 and finally through the outlet passage 31 and port 27.

The pressure force induced by the reciprocating diaphragm is exerted on the .fluid contained within the respective pump chambers and moves the fluid upwardly into the outlet channel 35 thereby causing the flap valve 45 to flex away fromthe block 25, as best seen in Figure 4, so as to open the end of the outlet passage 35 and provide an unobstructed path for the fluid thereto. Thus, as the free end of the actuating lever 13 is reciprocated to the left, as viewed in Figure 1, the diaphragm bulges into the right pump unit and the flap valve 47 of the left pump unit is urged away from the end of the inlet passage 33 allowing fluid to flow from the passage 33 downwardly into the inlet channel 37, as shown by the arrow in Figure l, and finally into the left pump chamber 19. The suction created by this reciprocating move ment tends to draw the flap valve 45 of the left pump unit more snugly into engagement with the end of the outlet channel 35 thus preventing any fluid in the outlet passage 31 and the valve opening 51 from moving downwardly into the left pump chamber. While a suction force is induced in the left pump unit of the structure shown in Figure l, the diaphragm causes the fluid in the right pump chamber to be subjected to a pressure force urging the ,fluid upwardly into the outlet channel 35 of the right pump unit, causing the flap valve 45 to flex away from the block 25, and allowing the fluid to pass freely into the passage 31 from which it can be withdrawn to a suitable conduit placed within the outlet port 27. It is seen that continuing the reciprocating movements of the actuating lever alternately cause the diaphragm 7 to pull or draw fluid .into one of the pump chambers while simultaneously causing an equal amount of fluid to be discharged from the other of the pump chambers.

It is evident that the stroke of the actuating lever 13 and the rate of reciprocation can be varied to control the rate of fluid flow. Further control of the fluid flow can be obtained by designing the valves 45 and 47 so that they flex to a certain degree when subjected to a specific suction or pressure force. This latter control can be accomplished by employing sheets 39 of certain desired thicknesses .and resiliency.

With reference to Figure 5, the modified diaphragm actuating lever 65 has its fulcrum or axis, indicated by the broken line 67, lying in a plane tangent to the openings forming the chambers 19. The innermost end of the lever 65 is formed with a substantially right angled portion 69 and a ring 71 which together are secured between the pair of flexible sheets 'formingthe diaphragm 7, while its outermost'end is provided with an arm 73 to which a reciprocating movement can be applied by any suitable means, not shown. Preferably, the central portion 75 of the lever 65 is not bonded *to the sheets'forming the diaphragm. The remainder of the pump structure shown in Figure 5 is thesame as described in regard to Figures 1-4. It will be noted that tapered recesses 21, as provided in the structure shown in Figures 1-4, are not necessary when theinodified diaphragm actuating lever is employed. However, the chamber blocks 17 are provided with corresponding arcuatev grooves, not shown, which together cooperate to form a passage for the central portion 75 of the lever 65.

The operation .of .this modified pump arrangement is substantially the same as explained above in regard to the structure shown inFigures 1-4, except that the actuatinglever 65 pivotsabout its axis -67 as a reciprocating movement is applied to the arm 73. The portion 69 and ring 71 of the lever 65 thereby cause the diaphragm to alternately bulge .in one direction and then the other to sequentially draw fluid into one of the pump units while simultaneously discharging an equal amount from the other of the pump units.

From the above description, it is seen that the various plates orblocks and sheets can be easily fabricated independently onanindividual basis with conventional equipment and'methods and that the parts, once fabricated, can be assembled without the use of any special skills or equipment. Further, the-parts can be madefrom chemically inert materials to eliminate any corrosion problems. The physical dimension of the pumps and their ability to deliver fluid in accurate amounts particularly suits them for use in laboratory work. Pumps have been constructed in accordance with the present invention which are 2 inches by 2 inches by 1 /8 inches and which deliver milliliters (ml.) of fluid per minute when driven at .12 revolutions per minute (R. P. M.). Smaller size pumps 1%, inches by 1% inches by 1% inches have also performed satisfactorily and are capable of delivering approximately 3.75 ml. per minute when driven at 12 R. 'P. M. with a inch stroke and 5 ml. when driven at approximately 4 R. P. M. with a /2 inch stroke. These pump dimensions are merely given as examples and of course not intended to be construed as limitations on the scope of the invention.

It is seen from the above description that the objects of the invention are well fulfilled by the structure described. The description is intended to be illustrative only and it is to be understood that changes and variations 7 may be made without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A double acting diaphragm pump having a pair of opposed pump chambers, a flexible diaphragm disposed between and separating said pair of opposed pump chambers, diaphragm actuating means connected in contact relation to said diaphragm and extending laterally therefrom, inlet and outlet means facilitating fluid flow into and from said pump chambers in response to movement of said diaphragm, and valve means for controlling the fluid flow through said inlet and outlet means.

2. A construction as defined in claim 1 wherein said actuating means includes a lever and said diaphragm includes two sheets of flexible material secured to each other in contact relation, with a portion of the lever interposed therebetween.

3. A construction as defined in claim '2 wherein said lever extends outwardly from said pump through a recess which terminates short of said pump chambers, with the portion of the pump intermediate the innermost end of said recess and saidpump chambers serving as a fulcrum about which said lever may be actuated.

4. A construction as defined in claim 2 wherein said actuating lever is adapted to pivot about an axis lying in a plane substantially tangent to said pump chambers.

5. A construction as defined in claim 1 wherein said valve means include resilient flap valves which cooperate with inlet and outlet means in response to the pressure and suction forces developed by said diaphragm for controlling the fluid flow.

6. A diaphragm pump formed of a plurality of elements secured together in juxtaposed relationship and including a first member having a pump chamber formed therein, a flexible diaphragm disposed against one face of said first member and closing one end of said pump chamber, a second member disposed against the face of said first member opposite said diaphragm and having fluid inlet and outlet means facilitating fluid flow into and from said pump chamber, a third member disposed against said second member and having valve means for controlling the fluid flow through said inlet and outlet means, means disposed against the face of said third member remote from said second member and forming an end member for said pump, and means for actuating said diaphragm, said actuating means including a lever connected in contact relation to said diaphragm and extending laterally therefrom.

7. A construction as defined in claim 6 wherein the first member is provided with a recess adjacent to said actuating lever and extending toward said pump chamber, with the area of said first member between said pump chamber and recess serving as a fulcrum for said actuating lever.

8. A construction as defined in claim 6 wherein said actuating lever is adapted to pivot about an axis lying in a plane substantially tangent to said pump chamber.

9. A construction as defined in claim 6 wherein said diaphragm includes a pair of flexible sheets secured to each other in contact relation with a portion of the actuating lever being interposed therebetween.

10. A construction as defined in claim 6 wherein said third member includes openings aligned with portions of said fluid inlet and outlet means, and resilient portions forming flap valves and cooperating with other portions of said fluid inlet and outlet means, said flap valves being flexible in response to the forces developed by movement of said diaphragm to control the direction and sequence of fluid flow.

11. A diaphragm pump having a pump chamber, a flexible diaphragm closing one end of said pump chamber, a diaphragm actuating lever connected in contact relation to said diaphragm, said diaphragm actuating means extending outwardly from said pump along a plane substantially parallel to said diaphragm and perpendicularly to the axis of said pump. chamber, inlet and outlet means facilitating fluid flow into and from said pump chamber in response to movement of said diaphragm, and valve means for controlling the fluid flow through said inlet and outlet means.

12. In a double-acting diaphragm pump having a pair of pump chambers, a diaphragm disposed between and separating said pump chambers, said diaphragm including a pair of flexible sheets secured to each other in contact relation, and an actuating lever interposed between said flexible sheets and having a portion extending laterally outward therefrom.

13. A construction as defined in claim 12 in which the portion of the actuating lever interposed between the flexible sheets is provided with an enlarged end.

References Cited in the file of this patent UNITED STATES PATENTS 109,678 Shearer Nov. 29, 1870 1,296,503 Gorrnan Mar. 4, 1919 1,811,557 Ove June 23, 1931 2,185,784 Corydon et a1. June 2, 1940 2,382,798 Langan Aug. 14, 1945 FOREIGN PATENTS 12,189 Great Britain June 30, 1904 929,832 Germany July 4, 1955

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