US2221071A - Pump - Google Patents

Description

Nov. 12, 1940. F. BARFO-D PUMP Filed May 29, 1,937

4 sheets-sheet 1 7 5 26 a l x I F1 2 INVEQTQR.

FEEDER/K Enema (67 z x q QKTTORNEX Nov. 12, 1940. F. BARFOD 7 2,221,071

' PUMP Filed May 29, 1937 4 Sheets-Sheet 2 96 INVENTQR.

F. BARFOD Nov. 12, 1940.

- PUMP Filed May 29, 1937 4 Sheets-Sheet 5 INVENTOR BHEFOD Tee-0521 15 4' Nov. 12, 1940. F 2,221,071

PUMP v Filed May 29; 1957 4 Sheets-Sheet 4 INVENTOR FZPEDEBIK BfleFoo 55 "1 It is accordingly an object, of

I v Patented Nov. 12, 1940 PATENT oer-lea rum Frederik Barfod, South Bend, ma, assignor to Bendix Products Corporation, South Bend, 'Ind.

a corporation of Indiana Application May 29, 1937, Serial No. 145,487

18 Claims. (.01; 103-152) This invention relates to pumps and more paradapted for operation by suction acting on one side of the diaphragm.- In pumps of'such char cter where applied to automotive vehicles forth purpose of pumping fuel by the useof manifold vacuum, it has been found that the manifold vacuum, during certain operating conditions is too low to raise fuel from the supply tank to the carburetor bowl, particularly where the operating area of the vacuum side of the diaphragm is substantially equal to the pumping area of the diaphragm, or in other words where the displacement in'the vacuum side i of the pump is substantially equal to that in the fuel side of the pump during each stroke; This was substantially the situation in the old vacuum systems employed in motor.vehicles, wherein no diaphragm was employed but wherein suction 0 acted directly on the fueldrawn from the tank, for in effect the surface of the fuel in the vacuum tank formed the equivalent of 'a diaphragm, gravity in that case maintaining the fuel separate from the subatmospheric air.

retion requiring less and lesssuction todraw fuel into the engine from the jets, and with the location of the float chamber bowl at a higher level due to the down draft arrangement, manifold vacuums have become lower and lower and it has in most cases beensconsidered necessary to provide a mechanically driven pump to raise fuel from the tank to the float chamber bowl. Because of the variable demand from such a pump which bears no direct relation to the speed of engine rotation from which-the'pump is driven, mechanical difiiculties arise, Also, the necessity for locating such a'pump close to the hot engine for simplicity of drive causes the phenomenon of vapor lock to arise during hot weather; Further, the pump, for the sake of drive simplicity, must often be placed at a point well above the fuel tank level, thus inviting vapor locks due to the suction head. a The present invention embraces a pump admirably adapt-d to take care of the fuel needs of an internal combustion engine by employing a vacuum pump 'of simple constructio which may act to draw fuel into it and discharge fuel thereunder pressure, and in addition employ a vacuum displacement on the side of the pump of double or more the displacement on the fuel side "of the pump. The motive power being vacuum,

the pump can easily be placed anywhere.

the present in- With the increased use of down draft carbuvention to provide a vacuum pump of the diaphragm type adapted' to draw fuel thereinto and to discharge fuel therefrom under pressure.

Another object of the invention is to provide a vacuum pump of the diaphragm type wherein the '5 the diaphragm area subjected to vacuum is substantially greater than the effective pump diaphragm area.-

l A further object-of'the invention is to provide a vacuum pump of the diaphragm type wherein 10 vacuum displacement fora given stroke exceeds pumping displacement. Yet another object of the invention is to provide a vacuum pump in which pump inlet suction is produced; as well as pump outlet-pressure, and '15 in which the total pressure head produced by the .pump may be substantially greater than the degree of vacuum being utilized.

Still another object of the invention is to provide a. vacuum pump of the double diaphragm 2 type, one diaphragm being adapted to store energy during the stroke in one direction to deliver energy to the stroke when moving in the return direction.

A further object is the provision of avacuum pump of simple'rugged design adapted to operate on pressures but slightly sub-atmospheric.

. The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in connection with the accompanying drawings. It is expressly understood, however, that the drawings are employed for, purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein similar reference characters refer to similar parts throughout the several views. V

Fig. 1 is a longitudinal section through a pre; ferred form of the pump:

Fig. 2 is a section taken on the line. 2-1 of "Fig. 1f showing vacuum valve actuating mecha nism from above;

Fig. 3 is an enlarged sectional 'view of. a portion of Fig. 1 showing vacuum valve actuating mechanism from the side; f I

Fig. 4 is a furthersection taken on the line 4-4- of Fig. 3 showing one of the valve positions;

Fig. '5 is a section correspondlngto Fig. 3

showing the valve invented position;

I Fig. 6 is a section taken on line-H of iiig t g5.

showing the corresponding valve positions when vented;

Fig. 7 is a longitudinal section through a modified form of the invention;

5 Fig. 8 is a fragmentary showing of Fig. 7 with the vacuum valve mechanism in shifted position;

Fig. 9 is a further modified form of the invention, and

Fig. 10 is a fragmentary showing of Fig. 9 with.

15 lower vacuum chamber section 26 with a second.

diaphragm 28 between the intermediate and lower sections, and a vacuum valve control section 30 therebelow,

The pump chamber is provided with an inlet 20 passage 32 having a check valve 34, and an outlet passage 36, having a corresponding check valve 38. Screw plugs 40 and 42 provide access to the valve parts and permit easy inspection thereof,

as well as access thereto for reseating purposes 25 if necessary.

The pump diaphragm 24 comprises a thin flexible member 44 clamped between the pump chamber section 20 and the intermediate section 22, the central portion of which member is clamped 30 between two rigid circular discs 48 and, 48 held together between shoulders 50 and 52 on the piston rod or valve stem 54. The annular portion 56 between the central discs and the casing is left slack so as to present at all times to the pump 35,chamber a concave annular portion. The pump diaphragm is limited in its movement between the face 58 f the pump chamber section 20 and an annular shouldered portion 80 of the inter mediate section 22, which latter portion is fur- 40 ther extended inwardly to form a partition 82 with an enlarged central opening 84 through which the stem 54 freely passes.

The second diaphragm 28 which is annular in shape is also formed from flexible material 63 45 clamped at its outer periphery between the easing sections 22 and 25. Its upper surface is exposed to atmosphere through ports 59 in the 'in-.

termediate section and its inner periphery is clamped between -an annular seat on the under- 50 sideof partition 62, and an annular clamping ring 65 drawn tightly against the'diaphragm by a plurality of fastening screws 66. A narrow annular portion of v the diaphragm centrally located with respect to the annular area thereof is 55- clamped between an upper annular plate 88 and an annular flange 12 of a cup shaped member 10, the flange I2 substantially corresponding in size with plate 68. Any suitable fastening means such as rivets (not shown) but passing through so the flange I2 and plate 68may be employed to secure the parts together. As in the case of the diaphragm 24, it will be observed that a certain amount of slack exists in the exposed portion of the diaphragm 63" 0 that the same presents a 65 concave annular surface. Upward movement of the diaphragm is limited by the engagement of the cup shaped member III with the clamping r'ing 55, and its lower movement is limited by the suitably shaped end wall I6 of the lower cham- 70 her casing section 26. ;A spring 18 centered around the cup shaped member I0 and seated on its flange 12 at one end, rests at it." other end in an annular groove 80 in the end wall of the easing section 25. The stem 54 passes loosely 7 through the cup shaped member I0 and is provided with a shoulder 84 adapted to engage the member I0, whereby the cup shaped member may by reason of the spring, urge the stem upward, as will be hereinafter explained more in detail. Also the cup shaped member I0 is provided with apertures II providing free communication therethr'ough.

"I'he lowerend of the valve stem 54 is 'pivotally connected to a lever 90 pivoted at 92 to the casins section 30 and forming a part of a snap-action valve actuating mechanism for controlling the vacuum and atmospheric pressures within the chamber 3|. As. shown in Fig. 4, the valve .mechanism comprises a valve adapted When down (see Fig. 6) to close off communication between the vacuum chamber 3| and the port 96 and source of vacuum, and a valve 98 adapted to close 011. the atmospheric connection I00 when up. Both of these valve elements 94 and 98 are loosely carried up and down simultaneously by a U-shaped lever I02 trunnioned at I04 on upstanding trunnions I06 and I08. For easy assembly the lever is provided with slots IIO where trunnioned at I04, and slots H2 and II 4 for engaging annular necked portions H6 and H8 on the valve elements 94 and 98, it being understood that the lever is retained in place by the snapaction tension spring I20 extending from a hole I22 in the transverse portion of the free end of the lever I02 and the lever 90. In order to assure maximum and full stroke operation ofthe pump, a second spring I24 ofthe compression type is provided in the valve mechanism, and extends from a notch I25 in lever 90 close to the fulcrum thereof and a point I28 adjacent the hole I22 in the U shaped lever I02. This spring tends to maintain thevalves either up or downuntil thelever 90 has moved sufliciently far in either direction as the case may be to tension spring I20 to overcome spring I24.

Operation of the pump is readily explained as follows: With the spring I8 expanded both diaphragms 24 and 28 are forced to the top position shown in Fig. 1 and the snap-action valve is tripped to the position shown in Fig. 4 just as this upper position is approached. Entrance of vacuum into chamber 3I draws diaphragm'28 down immediately compressing. spring I8 and draws diaphragm 24 down slowly, or as fast as fuel will flow into the pump chamber 2| past check valve 34. -When the chamber 2| becomes full, the stem 54 has, taken its lower position, moving the snap-action valvemechanism lever 90 to the position shown in Fig. 5, suddenly tripping ancl.causing the valves 94 and 98 to take the position shown in Fig. 6, whereupon the chamber 3| and the diaphragms 24 and 26 are subjected to atmospheric pressure. The energy stored in spring I8 is thus released and drives the valve stem 54 with diaphragm 24 upward slowly forcing fuel out of the pump chamber as fast as it can flow into the carburetorfloat chamber, which flow is of course'regulated by the usual float valve and carburetor demand. Thus on the down stroke, vacuum acting on the lower side of diaphragm 28 operates to compress spring I8 and that on the lower side of diaphragm 24 to draw fuel into pump chamber 2|. It is pointed out that if the suction head required to draw fuel into chamber 2I is very small, as where the fuel supply level is at or above the level .of the chamber 2|, the force applied to diaphragm 24 by vacuum can be transmitted through rod 54, shoulder 84 and cup I0 to aid in compressing the spring 18.

However, the maximum fuel inlet suction, against which the device as illustrated will operate, is restricted to the actual vacuum under diaphragm- .On the-up-stroke, the entire force of spring 1.8,

derived from the energy stored in the spring duringthe down stroke; is expendedcn diaphragm 24 in pumping fuel from. the chamber 2|. It is apparent that the actual fuel discharge pressure will depend upon the spring force and the area tributed. By making diaphragm large, a relatively stifi' spring can be utilized which in turn will result in the availability of a rather large force for pumping; also by making diaphragm.

24 relatively small the spring force will be distributed overa small area and will result in a relatively high discharge pressure. It is therefore apparent that by properly proportioning the sizes of diaphragm 24 over which said force "is dis-" since the valve mechanism must, in practice, trip of diaphragms 24 and 28 and properly designing the spring 18, the pump characteristics as to sure, and fuel pumping capacity can be varied through wide ranges. The energy for the pumping or return stroke isstored during the intake or initial stroke, but due to the second diaphragm, the force of the pump intake or suction stroke is not lessened. Further, since the lower diaphragm is free from the upper diaphragm, the concavity of the upper diaphragm is not disturbed-there alwa s being a pressur on the under side of the diap' ragm equal to orless than the pressure on the top, and therefore, the flexible portion of the diaphragm remains flexed downward reducing to aminimum any likely fatigue, and consequent rupture. This would not be so were diaphragm 28 rigidly fixed to stem 54. In practice, to increase the power of the pump,

it will of course be understood that a..Venturi booster may be used in conjunction with the 40 vacuum connection at 96. The Venturi booster being placed in the manifold posterior to the throttle assures constant suction for the operation 'of the fuel pump; With the use of such a maximum fuel inlet suction, fuel delivery pres-- venturi, as the throttle is opened upon acceler-- ation of the car, the mixture rushing into themanifold through the Venturl booster causes a depression at the restricted area whichistransferred to theconnected fuel pump causing its operation. 0n the other hand durin idling of the engine the suction in the manifold is great and the samebeing transmitted to the fuel pump aids its operation. Thus it may be seen that at all speeds suificie'nt vacuum is created to assure operation of the fuelpump. For a further description reference is made to the Chandler Pat- .ent 2,051,820 where boosters of suitable typeare shown at 80 and I18. i m the modification of Figs. '1 and 8, the diaphragms are arranged sideby side rather than concentric and the two are connected by a lever mechanism. The casing comprises a pump'sec- 'tion 29, and intermediate section222, betweenwhich is clamped the rim of the pump, diaphragm. 24. The pump diaphragm as beforeisconnected by a stem 254 with a snap-action valve mechanism enclosed in the vacuum valve lower section 30, and the structurethereof, in so far as the snap-action valvemechanism and section 30 is concerned-is identical ,to' that of Fig. 1, and 7 need not be considered again in detail.

1 The second diaphragm 228 is located large'aperture 225 by an annular section-226,

along side-of the first and is clamped'in place over and the diaphragm is urged to an upward posi- 75 tion by'a spring 218 seated in an annularshoulbefore the limit is reached.

In operation, when the chamber 3| is subjected to vacuum, diaphragm 228 is promptly drawn downward to its full limit of .movement, and pump diaphragm 24 is'drawn down as fast as fuel enters the pump chamber 2! and as dia phragm 224 reaches the lower limit, the-valve trips and chamber 3] is vented, thereby releas ing the energy in spring 218 which through levers 251 and 259 drives thepump diaphragm upward. a

In Figs. 9 and 10, the second diaphragm 328 has been located underneath the intermediate section 322, and a pair of levers 351 and 359 pivoted on the ,same fulcr 358 transmit the energy stored in spring 31 to the pump dia-' phragm 24, through an over-running connection comprising the jaw 380. on lever 351 engaging the pin 382 on lever 359. The-structure otherwise. is substantially similarfbut in operation less friction is encountered inthe lever. system I of Figs. 9 and 10 than in that of Figs. '1 and 8,

While the pump has been described as excep-- tionally useful in motor vehicle fuel supply systems, it should be understood that it has appli cation-in the general field as well, and the principle might equally well be applied to pumps operating from fluid under pressure in which casethe seconddiaphragm spring would move the first diaphragm down to draw fuel into the pump chamber. I

However, forautomotive vehicle use, it is obvious that the p mp can be placed at a low level so that notrouble can possibly be experienced in drawing fuel from the tank, and such positioning merely requires a vacuum connection, and positioning at a low level is further made possible due to the forced discharge. Minimum e i wear is also present since the pump audits parts move only in response to demancLand not in response to some continuously rotating drive member.

Though several embodiments of the invention have been illustrated and described, it is to be understood that the invention is notlimited thereto, but may be embodied in various me-- chanical forms and combinations as may be desired. Asvarious changes in constructionand arrangement of parts may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended-claims for a definition of the limits of the invention.

What ls'claimed is:

1. A pump comprising a chamber; a flexible diaphragm dividing said chamber into a pump portion and a vacuum actuation portion, means" for applying vacuum to said actuation portion to draw the diaphragm theretowards from an initial position, means for venting said actuasaid diaphragm, energy storing means associated with said actuation portion of the'chamber and tion portionafter a predetermined mov'ement of functionally independent of said diaphragm during the application of the vacuum to said actuation portion, said. energy storing means being adapted to store energy when subjected to vacuum, and means for delivering said stored energy to said diaphragm when said actuation portion is vented to return said diaphragm to said initial position.

2. A pump comprising a chamber, a flexible diaphragm dividing said chamber into a pump portion and an actuation portion, means for changing the pressure in said actuation portion to move said diaphragm from an initial position in one direction through a predetermined movement and for venting said actuation portion thereafter, energy storing means associated with said actuation portion and subjected to said changing pressure for storing energy during said movement of the diaphragm in one direction, said energy storing means being functionally independent of said diaphragm during said movement of the diaphragm and means for delivering said stored energy to said diaphragm to move it in the other direction back to said initial position when said actuation portion is vented.

3. A pump comprising chamber, fluid pressure responsive means div ding said chamber into a pump portion, and an actuation portion, means for changing the pressure in said actuation portion to move said fluid pressure responsive means from an initial position in one direction through a predetermined movement and for venting said actuation portion thereafter, energy storing means associated with said actuation por- .tion and subjected to said changing pressure for storing energy therefrom during said movement of said pressure responsive means in said one direction, said energy storing means, being functionally independent'of said fiuidpressure responsive means during said movement of the fluid pressure responsive means and means'for delivering said stored energy to said pressure responsive means to move it oppositely back to initial position when said actuation portion is vented.

4. A pump comprising a chamber, a flexible diaphragm dividing said chamber into a pump portion and an actuation portion, inlet and outlet valves connected to said pump portion, a vac uum inlet valve connected to said actuation portion and a vent valve, means foractuating said vacuum inlet valve and said vent valve simultaneou'sly and alternately to open one or the' other in response to diaphragm movement, a second flexible diaphragm in the wall of the actuation portion of said chamber, a spring adapted to be compressed by said second diaphragm when subjected to vacuum, and means for transferring the energy of the compressed spring to move said first named diaphragm when the vent valve.

close the vent, and a pump chamber having said "one diaphragm acting as a portion of the wall thereof.

6. A pump comprising a chamber, a flexible diaphragm dividing said chamber into a pumping chamber and an actuating chamber, means for admitting and discharging liquid from said pumping chamber in response to movements of said diaphragm, means for admitting vacuum and venting said actuating chamber in response to diaphragm movement, a flexible diaphragm means in the wall of said actuating chamber and adapted for actuation in response to vacuum within said actuating chamber, a resilient means for storing energy moved by said diaphragm means when actuated in response to vacuum, and means for transmitting said stored energy to said first named diaphragm, 'when said actuating chamber is vented.

7. A pump comprising a. casing providing a chamber, a flexible circular diaphragm dividing said chamber into a pumpichamber and actuating chamber, inlet and discharge ports for said pump chamber, valve means for admitting vacuum or venting said actuating chamber, a stem connecting said diaphragm to said valve means through" a snap acting mechanism, an annular reduced portion in said casing and extending into said actuating chamber, an annular flexible diaphragm forming'a wall of said reduced portion and concentric with said circular diaphragm and said stem, means resiliently biasing said annular diaphragm against vacuum pressure within the actuating chamber, and means on said stem and annular diaphragm adapted to cooperate with said biasing means to drive both diaphragms in a direction opposite to that produced by suction, when the actuating chamber is vented.

' valve operating lever having a limited movement,

vent and vacuum valves actuated thereby and controlling the application of vacuum and atmospheric pressure to said diaphragm, a second lever eccentrically pivoted with respect to the operating lever, and extending oppositely with respect thereto and adapted to oscillate about the line joining the fulcrums of said levers, resilient tension means connecting said levers, whereby movement of said second lever through a predetermined angle will cause said operating lever to snap from one end to the other of its limited movement, and a connection from said second named lever to said diaphragm. l

10. In a control mechanism .for a pump of the diaphragm type having a flexible diaphragm,'

a valve operating lever having a limited movement, vent and vacuum valves actuated thereby and controlling the application of vacuum and atmospheric pressure to said diaphragm, a second lever eccentrically pivoted with respect to the operating lever, and extending oppositely with respect thereto and adapted to oscillate about the line joining the fulcrums of said levers, resilient tension means connecting said levers, whereby movement of said second lever through a predetermined angle will cause said operating limited movement, a resilien compression element "extending from said operating lever to a point adjacent the fulcrum of said second named lever for positively urging the valves and the operating lever toward the limits of -its movement until overcome by said tension means, and a connection from said second named lever to said. diaphragm.

11. A vacuum operated'fuel pump comprising a pump chamber, a vacuum chamber, a circular diaphragm separating said chambers, and having a rigidcircular center portion and loose flexible annular portion, a stem secured to said center portion, a valve operating lever connected .to said 5138111, vent and vacuum valves actuated by said valve operating lever and controlling the application of' vacuunr and atmospheric pressure to said diaphragm, means associated with said lever for opening the vacuum valve to admit'vacuum when the circular diaphragm reaches one limit of its movement and for opening said vent to atmosphere when the circular diaphragm reaches the other limit of its movement, an annular flexible diaphragm surrounding said stem and having one side exposed to atmosphere and the other to said vacuum chamber, resilient means within the chamber urging said annular diaphragm against vacuum, and means for transmitting energy stored in said resilient means to said circular diaphragm to move the same when the vacuum chamber is vented.

12,-In a vacuum operated fuel pump, a casing formed in sections having adjacent .plane surfaces, a flexible diaphragm clamped between said surfaces and forming a pump chamber and a vacuum actuating chamber, a stem centrally secused to said diaphragm,,vacuum inlet and vent valve means actuated by said stem, a shoulder on said stein, a second flexible diaphragm annular in form surrounding said stem and exposed on one side to atmosphere and on the other to the vacuum chamber, and resilient means urging said second diaphragm into engagement with said shoulder.

13. In a displacement pump, a pumping member having one surface-in contact with the fluid being pumped, means i for intermittently subjecting another surface ofthe pumping member to motive fluid pressure to cause it to move throug a stroke, resilient means having'a oneway connection with said pumping member and operative to move it through its opposite stroke, and a pressure responsive member having one surface subjected to said motive fluid pressure and operative to compressthe resilient means energy storing means becoming operatively conto render the same inoperative during movement of the pumping member through said flrst men tioned stroke.

14. The invention defined in claim 13, wherein the effective area of said surface of the pressure responsive member is substantially greater than the effective area of said other surface of the pumping member.

15. In a pump, a pumping chamber, a variable pressure chamber, a pumping member movable in said pumping chamber and having a surface "exposed to pressures in said pressure chamber.-

means for periodically varying the pressure in said pressure chamber to-cause the pum'ping member to move through a stroke, a spring having a one-way connection with said pumping member and operative to move it through its opposite stroke, and a pressure responsive device having one surface exposed to pressures in said pressure chamber and operative to compress the spring to render it inoperative during movement of the pumping member through said first mentioned stroke.

16. The invention defined in claim 15, wherein the effective area of said surface of the pressure responsive device is substantially greater than the effective area of said surface of the pumping member.

17. In a displacement pump chamber, a source of suction,'a diaphragm for drawing fluid into' the pump chamber when sub-- jected to said suction, and means associated with said diaphragm including a movable wall exposed on one side to atmosphere and on the other to said suction for storing energy while said diaphragm is drawing in fluid, said energy storing means being structurally and functionally independent of the pum ng means during the energy storing period, a d thereafter said having a pump nected with the diaphragm to move the latter for discharging fluid from said chamber.

-18. In a -vacuum operated fuel pump, a source of vacuum, a vacuum operated means for. drawing fuel into the pump, and energy storing means including a diaphragm exposed on one side to atmosphere and on the other side to said vacuum for storing energy when said first named means is drawing in fuel, said energy storing means being both structurally and functionally independent of the pumping means during the energy storing period, and means thereafter connecting the vacuum operated means and the energy storing means for expelling the fuel from the pump. 1

FREDERJK BARFOD.

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