US2673522A

US2673522A - Diaphragm pump

Info

Publication number: US2673522A
Application number: US220253A
Authority: US
Inventors: John W Dickey
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1951-04-10
Filing date: 1951-04-10
Publication date: 1954-03-30
Anticipated expiration: 1971-03-30

Description

March 30, 1954 J. w. DI'CKEY 2,673,522

DIAPHRAGM PUMP Filed April 10, 1951 3 Sheets-Sheet l IN V EN TOR.

ATTORNE Y WITNESS: 4 5

March 30, 1954 J. w. DICKEY 2,573,522

DIAPHRAGM PUMP Filed April 10, 1951 5 Sheets-Sheet 3 IN V EN TOR.

an 100% WITNESS: Y

Patented Mar. 30, 1954 DIAPHRAGM PUMP John W. Dickey, Newfield, N. dix Aviation Corporation,

ware

Y., assignor to Bena corporation of Dela- Application April it, 1951, Serial No. 220,253

The present invention relates to a, diaphragm pump, and more particularly to such a pump in which the actuating mechanism is connected to diaphragms through hydraulic transmission means.

In reciprocating pumps such as used for supplying fuel to internal combustion engines, difficulty is sometimes encountered when pumping liquids containing impurities such as dirt, metallic particles, wax, gum, etc. which tend to clog the reciprocating parts. It is common practice therefore, to provide filters, magnetic separators etc. to remove solid foreign material, and to form the reciprocatory parts with liberal clearances to nullify the efiect of deposits on the walls of the cylinder and piston, thus reducing to some extent the efiiciency of the pump.

It is an object of the present invention to provide a reciprocating pump in which the reciprocating parts are sealed and protected from contact with the liquid to be pumped.

It is another object to provide such a device incorporating flexible diaphragms for propelling the liquid, said diaphragms being actuated hydraulically so that the pressures on both sides of the diaphragms are substantially equal at all times, and the diaphragms are accordingly not subjected to localized stresses, but serve merely as septums to separate the liquid to be pumped from the liquid sealed in the pump.

It is another object to provide such a device in which a small amount of air or other gas is sealed in the pump with the actuating liquid, so as to form a cushion and promote quiet and steady operation of the pump.

It is another object to provide such a device including a piston, a spring for projecting the piston, and an electromagnet for retracting the piston and cooking the spring; which is so arranged that the spring actuated stroke of the piston ejects a charge of liquid and draws in a new charge from the source of supply; while the cocking merely transfers a charge of liquid from one cavity in the pump to another, so that this stroke can take place rapidly irrespective of the rate of consumption of the liquid by the device being supplied by the pump.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which l is a vertical substantially mid-sectional View of a preferred embodiment of the invention, the electrical system thereof being shown diagrammatically;

from the pump stroke of the piston,

Claims. (Cl. 103-53) Fig. 2 is a section taken substantially on line 22 in Fig. 1;

Fig. 3 is a view similar to Fig. 1 on a reduced scale showing an embodiment of the invention arranged for mounting within the supply tank of the liquid to be pumped;

Fig. 4. is a sectional detail of the electrical terminal structure shown in Fig. 3;

Fig. 5 is a side elevation of the pump shown in Fig. 3, illustrating the method of assembly of the parts thereof; and

Fig. 6 is a top view of the same.

In Fig.1 of the drawing there is illustrated a substantially cylindrical casing member i of magnetic material near the lower end of which is rigidly mounted a partition and pole piece member 2 which is also of magnetic material. An upper partition member 3 is rigidly mounted in the casing 5 near the upper end thereof and a pump cylinder 6 of non-magnetic material is rigidly mounted at its ends within the partition members 2 and 3, the various joints between the partition member, casing and pump cylinder being rendered fluid tight by suitable means such as by soldering.

A piston 5 of magnetic material is slidably mounted within the pump cylinder :2 and is urged toward its upper position as illustrated by means of a, spring 6 bearing at its upper end against the end i of a counterbore 8 in the piston, and at its other end seating on a perforated bracket member s which is soldered as indicated at H to the lower end of the casing l. A cushioning spring i2 is seated in a counterbore the upper partition member 3 in order to prevent the piston from hammering against the partition member when the pump is operated while air bound.

Means for drawing the piston 5 downwardly so as to compress or cook the spring 6 is provided in the form of an electromagnet iii located in the casing i surrounding the pump cylinder 4, with its lower end seated against the lower partition and pole piece member 2, and its upper end in engagement with an upper pole piece member of magnetic material it which is rigidly mounted in the casing l in any suitable manner and closely surrounds the pump cylinder 4.

An electrical system for actuating the electrocomprising a battery i? one terminal of which is grounded as indicated at i t, the other terminal being connected through a manual switch is, insulated connector 2i sealed in the case i, and conductor 22, to one terminal of the electroinagnet it. The other terminal of it in. the upper end. of the piston and bears against the element it of- 3 :the electromagnet is connected by a lead 23 to a contact 24 which is arranged to cooperate with a contact 25, grounded at 26, to open and close the circuit through the electromagnet.

The means for actuating the

contacts

24, 25 which are here shown diagrammatically, is the same as that shown and described in the patent to Dickey et al. 2,472,067 issued June 7, 1949, so that it is believed to be unnecessar to further describe this feature since it forms no part of the present invention.

An inlet cap 21 is mounted on the lower end of the casing member I, the joint therebetween being rendered fluid tight by a flexible septum 28 which acts as a gasket to prevent leakage from the inlet chamber 29 formed within the cap 2'l.

An outlet cap member 3| is similarly mounted on the upper end of the casing member I, the joint therebetween being packed by the flexible septum and gasket member 32, the caps 21 and 3| being firmly held on the ends of the casing member 2, by suitable means such as the tie bolts 30 illustrated in Fig. 2.

The pump cylinder 4 and the spaces or

chambers

33 and 34 in the ends of the casing l are filled with a suitable liquid which is confined by the

flexible septums

28 and 32 so that the reciprocat ing movement of the piston is transmitted hydraulically to said septums.

The inlet cap 21 is provided with a threaded socket 35 (Fig. 2) for the reception of an inlet conduit from a supply source: and means in the form of a manually adjustable needle valve 35 is provided for closing the inlet when desired. The inlet opening 35 communicates with the inlet chamber 29 through a communicating passage 31 which is controlled by a check valve 38 arranged to admit fluid to the inlet chamber but prevent reverse flow thereof. A conduit 39 connects the inlet chamber 29 to the pump outlet 4|, which latter is in communication with the chamber 42 within the outlet cap 3|. A check valve 43 is located in the by-pass 39 permitting passage of fluid from the inlet chamber to the outlet but preventing backward flow thereof.

The inlet cap 21 is provided with a cup-shaped closure member 44 forming a sediment bowl which may be detached for removal of sediment or water in the liqui to be pumped, and which is normally held in assembled relation by suitable means such as a cap screw 45. A filter screen 46 is held by a seat member 4! within the sediment bowl 44 in position to strain out any solid matter suspended in the liquid to be pumped as it passes from the inlet 35 toward the passage 3! into the inlet chamber 29.

In order to quiet the operation of the pump and to form an hydraulic accumulator for increasing the efiective capacity of the pump, an elastic diaphragm member 48 is arranged to form the upper wall of the outlet chamber 42, and is enclosed by a dome-shaped element 49 forming an air chamber above the diaphragm 48 so as to cushion the action of the pump.

It has been found in use of pumps as here disclosed, that there is a slow drift of the liquid in the upper chamber 34 down into the lower chamber 33 due to leakage past the piston 5 under the output pressure of the pump. This leakage gradually distend the lower diaphragm and tends to impede the downward stroke of the piston and thus reduce the efficiency of the pump.

A preferred solution of this problem is to provide a check-valve-controlled passage in the Dis 4 ton to allow the liquid to flow up through the piston during the downward travel.

In Fig. l of the drawing such an arrangement is shown in the form of a tube having a press fit in an axial opening which traverses the solid portion of the piston 5, said tube being constricted at its lower end to form a seat against \svhich a ball valve 8! is pressed by a light sprin This ball check valve does not interfere with the action of the diaphragm 28 in moving liquid up through the by-pass 39 on the downward stroke of the piston since the pressure in the inlet chamber 29 is at that time the same as in the outlet chamber 42, except for the slight amount necessary to raise the check valv 43. Consequently the pressure in the

chambers

33 and 34. below and above the piston E are substantially equal, and there is no tendency to lift the ball check 8| except for the purpose of compensating for leakage past the piston 5 as above set forth.

In operation, starting with the parts in the positions illustrated in Fig. 1, closure of the manual switch 13 causes energization of the electromagnet l5, which draws the piston 5 downward, thus cocking the spring 6 and causing the lower septum 28 to expel liquid from the inlet chamber 29 past the check valve 43 and through the conduit 39 so as to enter the outlet chamber 42; such entry being permitted by the downward movement of the upper septum 32 which corresponds in direction and amount with the movement of the septum 2B. Deenergization of the electromagnet 15 by the opening of the

contacts

24, 25 in the usual manner permits the spring 6 to move the piston 5 upward, dilating the septum 32 and retracting the septum 28. The retraction of septum 28 draws a fresh charge of liquid from the inlet 35 through the check valve 38 into the inlet chamber 29, while the simultaneous dilation of the septum 32 ejects a charge of liquid from the outlet 4! to the device to be supplied by the pump. Since the downward stroke of the piston 5 as actuated by the electromagnet [55 merely serve to transfer the liquid to be pumped from the inlet chamber 29 through the conduit 39 to the outlet chamber 42, this stroke of the piston can always take place quickly so that the electromagnet is only energized momentarily. The upward strok of the piston 5 under the action of the spring 6 is controlled by the rate of consumption of the liquid by the device to be supplied. It will be understood that the

contacts

24, 25 are closed when the piston reaches the end of its upward stroke, and are opened at the end of its downward stroke, as fully set forth in the Dickey et al. Patent 2,472,067.

In Figs. 3 to 6 inclusive there i illustrated an embodiment of the invention in which the pump is arranged to be mounted within the supply tank for the liquid to be pumped. The actuating parts of the pump itself are the same as in the embodiment above described, and are similarly numbered, but the inlet and outlet caps are modified for the intended purpose. The inlet cap 5! is here provided with a downwardly extending threaded socket 58 adapted to receive a conduit 59 terminating with a funnel-shaped fitting 6| holding a screen 52 located adjacent the bottom of the supply tank 63.

The outlet cap ll is provided with a mounting flange 12 arranged to be attached to the top of the supply tank 63, with the body of the pump extending downwardly through an opening 13 in the supply tank, the flange being secured by suitable means such as cap screws 74 threaded into a recnforcing ring 15.

The battery connection is here brought out through an insulated connector 76 traversing the mounting flange 12 as illustrated in Fig. 4. A grounding clip 77 is preferably provided for insuring electrical connection of the pump with the body of the supply tank in order to insure completion of the electrical circuit.

In some installations it is desirable to provide means for permitting a slight leakage of the discharged fluid back to the supply tank so as to prevent undesirable syphoning of the liquid and also to prevent the building up of pressure within the supply caused by temperature changes when the system is idle. In the present system this is accomplished simply by drilling a small hole 78 in the conduit connecting the inlet and outlet caps of the pump so that liquid may leak slowly back into the supply tank.

In Fig. 3, the functions of the hydraulic accumulator diaphragm 48 of Fig. 1 are accomplished by trapping and sealing a suitable quantity of air or other gas in the space 34 below the upper diaphragm 32 of the pump. The imprisoned gas 79 provides elasticity in the actuation of the diaphragm 32 so as to quiet the operation of the pump and smooth out the flow of the liquid being pumped.

The operation of this embodiment of the pump is the same as the embodiment first described, and further description thereof is, therefore, deemed unnecessary.

Although but two embodiments of the invention have been shown and described in detail, it will be understood other embodiments are possible and that various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention.

I claim:

1. In a pump a cylindrical casing, a partition rigidly mounted near each end of the casing, a pump cylinder mounted at its ends in said partitions coaxially with the casing, means for sealing the pump cylinder in the partitions and the partitions in the casing, a piston in the pump cylinder, means for reciprocating the piston; inlet and outlet caps fixed to the ends of the easing, flexible septums closing the ends of the casing and packing the joints between the easing and caps, a, conduit conducting liquid from the inlet cap to the outlet cap, and a pair of check valves preventing back-flow of liquid through the inlet chamber and conduit.

2. A pump as set forth in claim 1 in which the piston is provided with an axial passage therethrough, and including further a check valve located in said passage and preventing backward flow of fluid through the passage when ferring conduit to the outlet cap.

4. A pump as set forth in claim 3 in which the outlet cap is provided with a flange and means 5. In a pump a casing, means including a pair of septums forming an inlet chamber and an outlet chamber oppositely located in the casing, a cylinder fixedly mounted in the casing intermediate said chambers, a piston slidably mounted in the cylinder, means for reciprocating the piston, said cylinder being filled with fluid confined by said septums, which fluid transmits the motion of the piston to the septums, a conduit connecting the inlet chamber to the outlet chamher and a pair of check-valves controlling the passage of fluid through the inlet chamber and conduit; the means for reciprocating the piston comprising a spring which moves the piston in a direction to cause liquid to be drawn into the inlet chamber and simultaneously discharged from the outlet chamber, and an electromagnet opposite direction, cocking the spring and causing the transfer of liquid from the inlet chamber to the outlet chamber.

JOHN W. DICKEY.

References Cited in the file of this patent UNITED STATES PATENTS