US2404983A - Liquid fuel pump - Google Patents

Description

July 30, 1946. 1.. PENGHLLY 2,@4,983

LIQUID FUEL PUMP Filed July 12;, 1943 2 Sheets-Sheet l Ill IN V EN TOR.

L. PENGELL! July 30, I946,

LIQUID FUEL PUMP Filed July 12, 1945 2 Sheets-$1199; 2

INVENTOR A f z W M" WEE Patented July 30, 1946 UNITED STATES? P O'FFI CE 5 claims;

This-invention relatesto a liquid elevatingdea simple and economically constructed pumpingdevice adapted for continuous operation in connection with an engine-for supplying liquid fuel thereto and arranged'to transmit pumping in pulses to a valvestructure in thefuel. tank byv meansof-an air column connecting said'structure with the pumping device.

It is also'an object of the invention to provide a liquid elevatingapparatus which includes a valve structure submerged in a supply of liquidwith a delivery pipe lea-ding therefrom; and withan air-pipe leading into said structure together with a pump connected to deliver a series of pressureimpulses to said air pipe with alternating suction impulses, and means rendering-the impulses effective principally in one direction for causing elevation of the-liquid into the delivery p p A further object/of the invention is to provide a-pumping device of simple construction, together with piping and check valves arrangedfor lifting liquid'fuel toan engine carburetor and-adapted for-continuous operation by the engine; but -arranged to automatically cease supplying said fuel when the carburetor is full, and to automatically replenish the supply when the'levelof fuel in theicarburetor falls.

Other objects and advantages of theinvention will appear'from the following description taken in connection with the drawings in-which:

Fig.- 1 is a schematic layout of an internal combustion engine and a fuel tank therefor, together with pumping mechanism and piping constructed in accordance with this invention.

Fig. 2 is a vertical sectional view taken principally-through the axis of the pump cylinder.- and showing the pump on an enlarged scale;

Fig. 3 is a fragmentary elevation. partly: in section through the valve chamber assemblylocated 'in'the fuel tank.

Fig. 4 is a vertical sectional view similar to F1812, showihgamodified pump construction.-

Fig. 5 is a vertical sectional view showing another'mcdification of the pump structure."

Fig. 6f-is a second schematic-layout showing -an internal combustion engine and-fuel tank there.-

forgtogether with 8.? modified valveassembly -in'- the :tank :and a-modifiea-pump at the :engine.

Fig: 7 -is.--a- :vert-ical sectional view showing 1 the pump: on-- an en-larged scale-as compared with Fig-,-:6:

Fig;:;8-'--is-a,-'fvertica-l:sectional view of the valve chamber andassociated parts located in the fuel tank showin'g;:this-strueture on an enlarged scale.

Fig;-9 is a verticalsectional view; of an air-inlet valveia-rra-nged irr-the air line-of -'-Fig.' 6.

While there is-shown-and-described-herein certain specific structure embodying;- the invention, itj-will.be-manifest-;to those-skilledjin the art that --variousmo difications and rearrangements of;the:partsmambeemadewithout departing from the-:scopee'obthe invention-,- and that the same is not:-- limited:- to: the particular forms hereinshown and describedyexcept in Y sofar as indicated-sb'y therappended claims;

This 'applicationa; continuation-m-part of my application Serial No;409;942,' filed- September 3.11941; patented June-13;;l944, No. 2,351,064:

In the-construction illustrated-in Figs. 1,2 and 3,-an-.internal-combustion engine is designated generally by thenumeral-l; anda tank containing-a supply-of .liquidfuehtherefor is'shown at 2 in cross-section; The engine has a carburetor 3- wliich includes the-usual fuel bowl and float valverwithin-the bowl: The acarburetort is connected by azfueldelivery pipe {5 to avalve chamber assembl-yi-located- Within the fuel tank 2-near the bottom' thereof; so-as torbenormally submerged -;by;-the. liquid fuel;

A-pump-6- is associated with thezengine' i so as to be driven continuously thereby; when the engine -is--.-runrli ng-,- as; for example,- by means of an eccentric 6; winch may-be secured to the usual cam-- shaft ofthe engine-the pump having a pitman fi -arranged-to be oscillated by said eccentric.-

The pumpffi is connected by an air pipe 1 to the-valve chamber assembly-5 in; the tank 2, and saidzpump includes :a cylinder 8 with a piston 9 arrangedeto be; reciprocated therein by means of the-pitman B The piston 9 is'shown with an annular 'groove ID at 'a-.s elected position between the topzand'bottom of the piston, and with a passage-.1 I extendingg-from the groove orcha-nnel ID to thealpper-:end-of the piston, as seen in Fig. 2.

The: cylinder 8 is provided with two spaced ports 12 and: l3 in-its sidewall, the upper port lz-beingian airinlet and the lower port l3-being a pressure-outlet to which the pipe -1 i connected for delivery of.-air impulsesto the-valve assembly 5 in -'the :fuelr tank; A passage (4 connects, the

The valve chamber 5 includes vertically spaced check valves [6 and H therein, the valve l5 open; ing inwardly with respect to the interiorof. the

chamber, and the valve l1 opening outwardly with relation thereto and controlling the delivery of liquid from the chamber 5 to the fuel delivery pipe 4, which has a terminal portion 4' within the chamber 5. Both the valves l6 and H are normally held seated by springs, as shown in Fig. 3, and the fuel inlet controlled bythe valve i6 is preferably provided with a filter screen 18.,

Whenever the engine I is running, the piston 9 reciprocates in the pump cylinder 8. On the down-stroke of the piston 9, suction is createdin the cylinder head until the channel In in the piston registers with the port 13, thus momentarily applying the suction through the passage II and through the air-line l to assist in lifting the bottom check valve IS in the chamber 5 and allowlng fuel to flow into the chamber; but the force of this suction is limited by the adjustment of the spring i5 which holds the check valve l5 seated, and said valve will open to admit air at atmospheric pressure whenever the force of the suction exceeds the strength of the spring On the up-stroke of the piston 9, however, the valve l5 remains seated, and the stroke is employed to compress air in the upper portion of the cylinder 8. When the groove or channel l0 registers with the port l3, this pressure is applied suddenly to the air column in the pipe- I, forcing the check valve H to open and lifting a portion of the fuel in the chamber 5 upwardly and past said check valve, into the delivery pipe 4. I

The action just described is repeated with successive strokes of the piston, with the result that the fuel is elevated, step by step, through the pipe 4, and delivered to the carburetor 3. The spring on check valve I6 is relatively light, so that when the pump is not in operation, the valve chamber 5 and the lower end of the delivery pipe 4 will tend to fill with liquid, to a height substantially equal to the level of liquid in the tank 2, However, when the fuel is being consumed rapidly by the engine I, the intermittent suction in the pipe 4 is helpful in insuring opening of the valve [6 to maintain a suflicient amount of fuel within the chamber 5.

The provision of the air inlet port l2 and check valve l5 operates to limit the suction produced by the pump to considerably less than that corresponding to a full piston stroke, and this suction is at no time suihcient to lift the liquid into the air-line l to a height more than slightly above the level of fuel in the tank. Even if the carburetor is filled, and its float valve prevents the further delivery of fuel through the pipe 4, the

continued operation of the pump will not suck 6 the fuel above the said level in the pipe 1. However, as a precaution, and particularly when the system is installed on a vehicle which may not always travel on a level road, I prefer to provide an inverted syphon in the air-line I by extending the pipe for some distance above the fuel tank in excess of that through which the suction effect could be operative, as shown'at l in Fig. 1.-

Since the cylinder 8 is thus vented to the at.- mosphere before the piston completes its full suction stroke, whereas, in the opposite direction, the piston operates through its full stroke to deliver a pressure impulse to the air-line I, the result is a succession or series of impulses, which are effective principally in one direction, along the air line 1, and for elevating liquid from the chamber 5 into the delivery pipe 4. Particularly when the pump operates at relatively high speed, as it does in connectionwith aninternal combustion eninefof the autornfotive'type; there a, tendency for some of the air in the pipe 1 tobe passed into the liquid in the chamber 5 and to be discharged therewith. This would operate to rarefy the air in the line I, but any such loss of air is at once replaced .by way of the check valve l5 and passage l4 during the suction stroke of the piston, because with the air in the pipe 1 rarefied to any extent, the suction produced by the piston will reach a higher value than the spring l5 can resist, and atmospheric pressure acting upon the valve 15 will open it to supply air to replace that which has been mixed with the liquid fuel and delivered from the chamber 5 therewith.

Fig. 4 shows a modified form of pump in which the cylinder 29 is connected to the air-line l through an outlet port 2|. The piston 22 is formed with a passage 23 extending from the top wall of the piston and through the side wall thereof for registration with an air supply port 24 in the side of the cylinder 20 when the piston reaches the lower limit of its stroke. Thus, at each suction stroke, atmospheric air is supplied to the cylinder in whatever quantity is required to replace any loss from the air-line 1, and each pressure stroke is thus fully effective to provide the desired pulsation in the air column in the pipe I for lifting the check valve H and passing fuel from the chamber 5 into the delivery pipe 4. With this arrangement, no check valve need be provided in the air intake for the cylinder 20, since the port 12 is never uncovered, except at the extreme limit of piston travel, and this port is closed substantially at the beginning of the pressure stroke.

Fig. 5 shows a modified form of pump suitable for mounting in the side wall of the engine crank case adjacent the position of the cam shaft 25 therein, which is shown with an eccentric 25 operating against a stem 21 on the end of the piston. The cylinder 28 is indicated as integral with the side wall 29 of the engine casting, and is provided with an applied head 30 having a central port 3| into which the air-line 1 is connected. The head 30 includes a pocket 32 which may be of smaller diameter than the interior of the cylinder 28, and accommodates a spring 33 coiled about a guide extension 34 on the end of the hollow piston 35, the spring 33 serving to maintain contact of the stem 21 with the operating eccentric 26. This pump may be provided with air inlet facilities, either of the type shown in Fig. 2 or in accordance with the arrangement shown in Fig. 4, but, as illustrated in Fig. 5, the piston35 is not provided with any port or passage, as in said structures, and is intended for use with an air supply valve arranged in the line 1 in a manner about to be described.

Fig. 6 shows a layout somewhat similar ,to that of Fig. 1, but in which the particular pump illustrated is of modified construction, and the valve chamber in the fuel tank also includes some features not found in that of Fig. 3; and in this arrangement the air lost by admixture with the fuel in the pumping operation is replaced by means of an air inlet valve connected into the ai'r uile- 1; as showman 4 01 Air engine iscon-- ventionally"illustratedat41, with a fuel supply tank at iz anda carburetor at 43." A' delivery pipe 44' extends'fr'om the valve chamber assemb y'l 5; and"apuhipis"shown"at applied to the sidewall of thecrank case fora'ctuation by a cam'oreccen't'r'ic Monthe'cam' shaft of the engine.

The'p'ump' 46 is 'shownin' FigJI as including a cylinder 48havinganfoutlet 49, at one end of which. the". air-line l i is" connected. The flange 5 "atthe' other: end of'thepylnder is bolted to the side wall of the"engine',' indicated at 4 l and at this'end of thecylinderthere is "provided a guide 5| for the piston rod 52, which is'se'cured 'ii'rthe eh'd'wall of the piston" 5-3. A spring-54 is coiled about .the" outer-end ip'ortion'of the piston rod Sl and reactsbetween'said guide 5| and ahead 55 on" thero d. Theheacl 55 is engage'd'by' a eccentric 58"01'1" the'cam'shaftfilof the engine, as seenin 7; but the stroke" of" the piston is limi'ted by" rf1ean's of a' stop collar-58 on the piston rod 52", said" collar abutting the'guide member 51 to provide clearance at 59*betW-eenthe head 55" and' the'e'ccentrici at. This allows a brief interval at the :endv of 'th'e'stroke; permitting the valves inthe"'fu'el' elevating device to'operate to bette'r advantage, so as to perform more efficiently'at high speed;

The pumpingchamb'er' E5; whi'chis shown in detail inFig. 8; includes an inlet-valve 69 seating outwardly with respect to the chamber, and an outlet wave 6! seating'inwardlywitlr relation t'o'said chamber. These valves are'held normally seated by their'sp'rings, as'seen in Bfand the 5 pressure impulsetransmitted through the pipe 1 operates to open the valve 6| and to pass liquid fuel from the chamber $5 above the valve, in the same manner as with the structure of Fi 3. But to improve the operation an air dome 62 is formed in the assembly surrounding the terminal portion 64 of the delivery pipe 4, said terminal portion being shown as an integral part of the cast chamber 45. Any air which is admixed with the liquid fuel, either in the tank Or by virtue of the application of the air column in the line 1 to the liquid in the chamber 45, tends to free itself from the liquid as the latter passes the valv 6i, and to accumulate in the air dome 62. This provides an air cushion against which the pumping pressure operates, and which helps to force the liquid upwardly through the delivery pipe 4 and to maintain a reasonably uniform flow therethrough, damping out the pulsations produced by the operation of the pump at 46.

Replacement of air lost from the air-lme 'l in the pumping operation is effected by means of the check valve device 45, which includes a gravity seated disk valve H1 and an air inlet port "H provided with a regulating screw I2 by which the capacity of the port may be varied, as may be found desirable in view of the particular installation of the apparatus. Thus, upon each suction stroke of the pump 46, if the air column in the pipe i has been depleted by leakage or by loss of air absorbed in the liquid fuel, this leakage or loss will be replaced by the automatic opening of the check valve iii, admitting air through the port l'l during the brief suction interval.

This substantially continuous addition of air to the line 1 may sometimes tend to build up a pressure in the line in excess of that which is desirable, and such pressure is automatically relieved by means of a valve 65 which forms the lower 'end' wall-of t-he chainber- 45.- The -valve disk is' seated upona-supporting disk- 66' carried by a sprin'g G'I which is shown eonveniently' dis posec'l in an an uiars ace aroune tne: inlet screen 63. A cen'tial-opening 'iir 'the dislo lifi is defined byan upwardly projecting annular flange 69 which forms' the inlet passage and provides the seat for 'theinlet-vall'le-Gfl. With thisarrangementj-whenever thepressure in-the'line l exceeds the tensiono-f the-spring 61, this'pressure transmitted through the chamber 45 will depress-therelief vault/e 65 so thatthe excess of air may escape through thescreen 68 in'to the tank; 'This will teh'd 'to'produce soine turbulence in the liquid adjacent theinlet to the'=chamber '45,:with the result th'at the air' imthis-vicinity will find its way't6' 'the air dame- 62 -as 'theliquid is pumped up "irito th cha'nibeif"45; and"- will -thfis serve to maintain-thedesi'red air cushion in l the-dome 6 2- foi" facilitating-the new oi liquid throughthe pipe" 4.

With referefi'c'e to'the clearance shown'at 59 in Figz 'l; between tne: cam 56 and the head of the piston '-r0d '52, it will -be 'under'stood that the delay interval effected by ine-ans of this clearance might alsobe 'seeured by making the corresponding portion'- of th'e cani concentric with its axis of rotation; There isalso'shown in Fig. '7, near the rightmand'endof the pump cylinder 48, a restrioted 'port 4821' 1 for-ined' in the side wall of I the cylinder and pbsiti'Oned tO be uncovered by the piston .a't'the' end ofitssuction stroke. If the check valve 40 is employed, this port will ordinaruy b'e-plug'gedup, but, if preferred, this inlet portmay e utilized in placeof the" air'inlet cheeldv'alve' fw tfiinsure -replacement of such au as-maybe lostfrom the" air colunin' in the pipe 1 by absorption in the liquid fuel, or otherwise.

In most pumping devices of this general character for moving liquid fuel, the difiiculty commonly known as vapor lock is frequently encountered; but in the structures herein disclosed this trouble has been overcome partly by the automatic replenishment of air as required in the pressure line 7, and also by virtue of the relief valve provided at 65, which avoids the accumulation of excessive pressure in the line. Frequent operation of the air inlet valve IE or 10 and of the valve tends to disturb or agitate the air column sufficiently to insure its proper functioning at all times.

I claim:

1. In a liquid elevating system which includes a liquid supply, a chamber having an inlet submerged therein and a delivery pipe leading upwardly therefrom, said chamber comprising an outer cylindrical body having a top wall, an inner cylinder suspended in the outer cylinder in spaced relation thereto and having an outlet port in its lower end, a delivery tube connected with said delivery pipe and depending from the top wall of the outer cylinder within the inner cylinder, said tube terminating in spaced relation to said outlet port, an outlet, valve disk seated over said port, a coil spring supported on the lower end of said tube and holding the outlet valve yieldingly to its seat, an outwardly seating valve for the submerged inlet of the chamber, and an air pipe leading into said chamber with pumping means supplying alternate suction and pressure impulses to actuate said valves and force liquid from the chamber into the delivery pipe.

2. In a liquid elevating system which includes a liquid supply, a chamber having an inlet submerged therein and a delivery pipe leading up-' wardly therefrom, said chamber comprising an outer cylindrical body having a top wall, an inner cylinder suspended in the outer cylinder in spaced relation thereto and having an outlet port in its lower end, a delivery tube connected with said delivery pipe and depending from the top wall of the outer cylinder within the inner cylinder, said tube terminating in spaced relation to said outlet port, an outlet valve disk seated over said port, a coil spring supported on the lower end of said tube and holding the outlet valve yieldingly to its seat, a bottom wall for said chamber in which the said submerged inlet is located directly below said outlet port with an upstanding annular flange surrounding said inlet as a valve seat therefor, an inlet valve disk on said seat, an annular flange depending from the inner cylinder in spaced relation'to said inlet valve disk with a spring coiled about said flange and holding the inlet valve yieldingly seated, and an air pipe leading into said chamber with pumping means supplying alternate suction and pressure impulses to actuate said valves and force liquid from the chamber into the delivery pipe.

3. In a liquid elevating system as defined in claim 2, said outer cylinder having a downwardly facing annular shoulder against which said bottom wall is normally seated, and spring means holding said bottom wall to said seat, whereby said bottom wall serves as a relief valve adapted to yield to release excessive air pressure in the chamber.

4. In a liquid elevating system which includes a chamber having an outwardly seating inlet valve and an inwardly seating outlet valve, a delivery pipe controlled by the latter valve and an air pipe leading to said chamber, a pump comprising a cylinder and a piston reciprocable therein creating alternate pressure and suction impulses, said cylinder having a continuously open port into which theair pipe is connected and through which pressure and suction impulses are transmitted to said chamber to actuate the valves thereof and elevate liquid therefrom through the delivery pipe, means automatically supplying air to the air pipe during the suction impulses to replace air expelled therefrom by the pressure impulses, and means providing a delay in the reciprocation of the piston at the end of each suction stroke to facilitate operation of the valves in said chamber.

5. In a liquid elevating system which includes a chamber having an outwardly seating inlet valve and an inwardly seating outlet valve, a delivery pipe controlled by the latter valve and an air pipe leading to said chamber, a pump comprising a cylinder and a piston reciprocable therein creating alternate pressure and suction impulses, said cylinder having a continuously open port into which the air pipe is connected and through which pressure and suction impulses are transmitted to said chamber to actuate the valves thereof and elevate liquid therefrom through the delivery pipe, means automatically supplying air to the air pipe during the suction impulses to replace air expelled therefrom by the pressure impulses, means to reciprocate the piston comprising a cam for driving it in one direction and spring means to return it, said cam being arranged to provide a delay in the reciprocation of the piston at the end of each suction stroke to facilitate actuation of the valves in said chamber.

LEWIS PENGILLY.

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