US1775506A - Limited-pressure feed device - Google Patents

Description

Sept.V 9, 1930. c. s. BURTON LIMITED PRESSURE FEED DEVICE 2 Sheets-Sheet l Filed March 31, 1923 Sept. 9, 1930. c, s, BuRroN 1,775,506

` LIMITED PRESSURE FEED DEVICE Filed March :51, '192s z sheets-snee: 2

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r I I Patented Sept. 9, 1930 UNITED STATES PATENT OFFICE CHARLES S. BURTON, OF OAK PARK, ILLINOIS, ASSIGNOR TO STEWART-WARNER COR- PORATION, OF CHICAGO, ILLINOIS, A. CORPORATION OF VIRGINIA.

LIMITED-PRESSURE FEED DEVICE Application led March 31, 1923. Serial No. 628,951.

The purpose of this invention is to provide an improved construction for supplying liquid fuel to an internal combustion engine from a main supply tank situated at a lower level than the carbureter intake. It consists in the elements and features of construction shown and described as indicated in the claims.

In the drawings Figure 1 is a diagrammatic view of the nature of a side elevation of an automobile having its engine equipped with this invention, showing the relative position of the several elements which (2o-operate in the fuel feeding.

Figure 2 is a vertical fore-and-aft section of the main fuelv supply tank, and specifically of the fuel feeding device which is intruded thereinto, the tank and said device being broken away to reduce the vertical extent of the figure.

Figure 3 is a plan view of an air-pumping device operated by alternating pressure and suction derived from one cylinder of the engine for developing the airpressure by which the fuel elevating device shown in Figure 2 is operated. f

Figure 4 is a section at the line, 4-4, on Figure 3.

Figure 5 is a detail section at the line 5 5, on Figure 3.

Figure 6 is a side elevation of the liquid pumping device which is intruded into theV main fuel tank.

Figure 7 is a top plan View of the same. Figure 8 is a section at the line 8-8, on Figure 6.

Figure Figure 2.

Figure 10 is a section at the line, 10-10, on Figure 7.

9 .is a section at the line 9-9, on

Figure 11 1s a vertical section of a suction` force pumping device which may be employed for fuel feeding, being immersed in the main fuel tank and connected with the air pumping device operated by engine con nection.

Figure 12 is a detail vertical section showing a standpipe on the fuel feed line near the' carbureter.

Figure 13 is a detail sectional view showing a modification of the construction as appearing at the horizontal plane of the axis of a turn-cock, corresponding to turncock 41, seen in Figure 4.

Figure 14 is a detail section of a check valve evice which may be interposed from the pipe line of the engine for a certain function. In the construction shown in the drawings the automobile engine is indicated at A; the main fuel supply tank is indicated at B; C indicates in general an air-compressing pump device connected at one side with one cylinder of the engine, and at the other side with the liquid pumping device in the main tank. D indicates in general and in its totality the liquid pumping device in the main tank. 4

The air-compressing pump operated by the alternation of suction and pressure derived from one cylinder of the engine will be first described. This device consists of a cast f1tting, l, which has a duct, 2, for connection at the intake end by means of a pipe, 3, with one cylinder of the engine, the connection of the pipe with the fitting being made in any convenient manner, being shown in a familiar manner employing a compression coupling, 4. This duct entering horizontally is deflected at right angles and terminates through the downwardly-projecting nipple, 5, which is constructed for coupling to the upper end of a U-tube, 6, preferably of glass, and coupled by means of the stuiing box coupling, 7 The other end of this U-tube is similarly coupled to a second downwardly-projecting nipple, 8, of the fitting, 1. In this nipple and the horizontally-extending adjacent end of 'the tting, there is formed an air discharge duct comprising the portion, 9, extending vertically in the nipple, 8, a valve chamber, 10, at the upper end of said ,duct portion, 9, and a horizontally-extending portion, 11, leading to the said adjacent end of the fitting, 1, into which is coupled the pressure pipe, 12, which leads to the liquid pumping device in the main tank. In the valve chamber, 10, there. is a check valve, 13, seat-ing downwardly for closing the duct, 9, against return flow towardthe U tube, 6.' Leading oiil horizontally and laterally from the duct, 9, at a point below the seat of the valve, 13, there is a duct, 15, which leads to a valve chamber, 16, from which a duct, 17 leads to the atmosphere. A check valve, 18, in this valve chamber, 16, seats downwardly to prevent discharge and permit intake of air through the terminal duct, 17. 19 and 20 are plugs screwed into tapped holes bored to form the valve chambers, 10 and 16. In line with the duct, 11, and extending in the opposite direction from the valve chamber,'10, is a duct 22, which connects with a vertically-extending duct, 23, to be closed by a valve, 24, held yielding/ly to its seat, 23, by a spring, 25, coiled around the stem, 26, of said valve stopped at the lower end on the valve, and at the upper end upon a tension-adjusting screw, 27, screwed into the standard, 28, eX- tending up from the upper side of the fitting, C. As illustrated, the duct, 22, the valve seat, 23, and standard, 28, are provided by a unitary fitting screwed into a tapped bore in the upper side of the main fitting, C. As illustrated, also, the duct, 23, has connection with the duct, 2, leading from the engine,l

said connection being controlled by a turn- A cock, 110, which may be set to connect the rellef duct 23, alternatively either with the duct, 11, or with the duct, 2, for a purpose hereinafter described.

The U tube, 6, is occupied by a suitable liquid, preferably mercury, to operate as a liquid piston which shall reciprocate in the tu e responsive -to the alternating pressure and suction derived from the engine through the ipe, 3, and duct, 2. Preferably there are oated upon the upper ends of the liquid piston, 30, cork loat valves, 31, and 32, for seating at the lower ends of the ducts, 2 and 9, respectively, and stopping the' thrust of the liquid piston in its movement responsive respectively to the suction and pressure. 'Desirably these cork oat valves are each provided with a pendant weight or tang, 33,

i which may be a screw screwed into the cork and serving both for holding the oat in true vert1cal position and also for giving the liquid plston frictional or capillary grasp upon the float valve to insure the latter moving with the surface of the liquid piston.

.Upon considering this air pumping device, it will be understoodV that in the suction phase of the cycle of the engine cylinder with which the device is connected, the liquid plston will be actuated for reciprocation upward at the end toward the engine connection. causing air to be drawn in at the air intake, 17, past the check valve, 18, and that upon the pressure phase of said engine cycle 4 the liquid piston will be driven in the opposite direction, thrusting upward its end remote from the engine connection and driving out the air past the check valve, 13, and out through the pipe, 12, leading to the liquidpumping device in the main tank; and it will l be seen that at each successive reciprocation of the piston in the engine cylinder which is thus connected, additional air will be driven through the pipe, 12, and that eventually pressure will be accumulated in the liquid-pumping device to any desired degree -up to the maximum pressure aiforded by the adjusted to limit the l pressure produced toL any desired degree by adjusting the tension screw, 27.

As thus far described, this air pumping device is designed and adapted to co-operate with a liquid-pumping device in the main tank of a character to be operated by continuous air pressure on the liquid in a chamber having connection for discharge of liquid toward the carbureter. 'If it is desired to supply the fuel to the carbureter by any ordinary suction and force pumping device operated by alternate suction and pressure, the air-pumping device described may be utilized for this purpose by virtue of a by-pass duct, 40, shown in Figure 4, connecting the ducts, 9 and 11, by-passing the valve, 13, and causing the alternate suction and pressure operating at the engine side of the liquid piston to produce similarly alternating suction and pressure in the pipe, 11, 'which will be connected to a simple suction-and-force-pump device hereinafter described, submerged in the lfuel supply in the main tank. A shutoif valve or turn-cock, 41, controls the bypass duct, 40, and will be closed when the device is operated in the manner first above described for producing continuous air pressure through the pipe, 12, and opened only when the device is employed in the last described manner for operating a simplel suction and force pump device in the tank. When it is thus employed, it will be understood that the check-valve, 16, will be forced to its seat by screwing in the plug, 20, so as to prevent the suction from being satisfied by direct air inlet and so failing to operate in the line leading to the suction and force pump.

Figure 13 shows a modification dispensing with attention to the plug, 20, as described, when the turn-cock, 41, is opened, said modification consisting in leading oif the duct, 15, in a direction to intersect the axis of the turn-cock, which is then extended soas to Dfi control said duct, 15, the turn-cock having a port, 41a, which registers with the duct, 15, at one position of the turn-cock, permitting air intake when the turn-cock is at closed position as to the by-pass, 40, and closing the duct, 15, when said by-pass is opened.

Theliquid pumping device in the main tank of a character to co-operate with the air pumping device above described when operating as first above described, comprises a cast fitting, 50, adapted to be inserted in and mounted at an aperture, b, in the top of the tank, B. Said fitting has a nipple, 51, for connection with the air pipe line 12, leading from the air pumping device, and a nipple, 52, for connection with the fuel pipe line, leading to the carbureter. The nipple, 52, receives, thrust down through it, the terminal portion ofthe fuel pipe line, 54, which leads to the carbureter, the said pipe terminal be-` ing connected liquid-tight at said nipple by means of a familiar form of compression coupling, 55, shown in the drawings. This pipe terminal extends down within a larger passage or chamber, 56, partly formed in a boss,

50g, extending from the lower side of the fitting, 50, and partly formed by means of a pipe, 57, screwed into said boss and extending down in the fuel tank to near the bottom thereof for connection at its lower end to the second cast fitting, 60, hereinafter more particularly described. The nipple, 51, receives the terminal portion of the air pipe line, 12, said terminal being inserted liquid-tight through said nipple and secured thereto by a compression coupling, 58, from the nipple mouth, a duct, 51a, extends down in an extension 50f, at the left hand side of the boss, 50g, as seen in Fig. 2 and Fig. 9, and connects with a horizontal duct, 82, from the other end of which a duct, 84, leads down through a downwardly-projecting nipple and coupling, 59a, which is connected by a pipe, 59, with an 11p-turned nipple, 62, of the fitting, 60, the connection of said pipe, 59, at both ends with said nipples respectively, being made by compression couplings, 59a, 59h, the pipe being of sufficient length to intrude at its opposite ends into the two nipples loosely enough so that it may be introduced into one of them at the slightly oblique angle made necessary by its length and the presence at the other end of the other nipple, and thrust into the first mentioned nipple far enough to permit it to be swung over into line with the `two nipples and retracted into the second nipple, preparatory to tightening the compression couplings. The nipple, 62, is connected by a cross duct, 63, with an upwardlyprojecting nozzle, 64, which is situated centrally with respect to a hollow boss, 65, to which the lower end of the pipe, 57, is screwed. Thisyhollow boss has its cavity in what may be termed hour-glass form for constituting a Venturi tube, and is apertured around the base of the nozzle, 64, for inlet of liquidjuel from the tank into said Venturi tube.

Upon considering this construction, it will be seen that the nozzle, 64, is in continuous connection with the air pipe line, 11, so that compressed air delivered through said pipe, 11, is discharged upwardly in a jet from the nozzle, 64, within the Venturi tube and will thereby act upon the liquid for driving it upward within the chamber formed by the pipe, 57, and passage, 56, in the hollow boss, 50, of the fitting, 50, the air acting partly 'as a piston behind the liquid, and partly for aerating the liquid to some extent. .The air which penetrates and acts for aerating the liquid tends to escape, and does escape, to a large extent in the upper part of said chamber, 56, which upward from the lower end of the pipe, 54, constitutes an air trap, the air which becomes separated from the liquid in this trap being still under a very considerable degree of compression, but operating with less pressure upon the liquidbelow it than is produced by the more' highly compressed air delivered from the nozzle in the venturi. The co-operation of the compressed air in the trap and the driving action of the more highly compressed air jet from the nozzle, forces the liquid up through the pipe, 54, and on to the carbureter. At any convenient point in this liquid pipe line, there may be interposed a check valve to prevent backflow of the liquid. Such check Valve x is shown and is prefera-bly located at the foot of a little standpipe, 70, which is erected on the pipe-line, 54,

immediately in front of the dash for a specific function hereinafter mentioned.

Obviously in the absence of provision for preventing it, there will occur an accumulation of compressed air escaped from the liquid fuel in the air trap portion of the chamber 56, formed by the pipe, 57, and the cavity, of the fitting, 50, which accumulation would eventually in the absence of preventing means, occupy the entire trap space and extend down to the intake end of the pipe, 54, and would then escape through said pipe, with the undesirable result of aeratingthe liquid fuel which i-s being fed into the carbureter. It is necessary, therefore, to provide for venting this air trap at a pressure limited so that the same shall not find its vent through the pipe, 54, as mentioned. For this purpose the fitting, 50, has an extension to the right hand as seen at 50% Figure 9, through which there is formed a duct, 50", communicating at its left hand end with the upper portion of the air trap, 56; and intersecting this duct, 50h, there is-made a vertical bore, 50", counterbored from the upper end as seen at 50y forming an upwardly-facing valve seat, 50, and a valve, 50d, is provided seating on said seat having its stem extending up through a guide and spring -tensioning plug, 50e, screwed into the upper Counterbored end of the boss, 50a, for stopping the upper end of the spring. This plug or tension screw may be screwed down to tension the spring 50, to any desired degree so that pressure in the air trap chamber beyond that degree will open the'valve and permit the escape of air out through the boss which is laterally apertured at 50m, into the main fuel tank. Notwithstanding the air pumping device above described may be provided with the safety ventvalve for limiting the air pressure which can be developed by said device, it will be found advantageous to provide a similar airpressure-limiting safety valve on the liquid pumping device in the tank, and such airpressure-limiting safety valve is shown at 84, seating on a seat, 81, provided in the duct, 84, which extends up from the connection therewith of the horizontal cross duct, 82, and is counterbored at 83, in forming said valve seat 81 to form a valve chamber and spring chamber there-above for the valve, 84a, and the spring, 85, coiled |about the valve stem 84W and reacting between said valve and the tensioning and valve-stem guide-screw, 86, screwed into the upper end of said counterbore. The stem, 84", is fitted-loosely in the part, 86, for affording air` vent from the chamber, 83. The two pressure-limiting devices above described, one for limiting the pressure and permitting the venting of air from the air trap chamber, and the other for limiting the initial operating pressure from the pressure pipe line, are entirely similar and may be relatively adjusted to each other to insure the venting of the air trap rbefore thev pressure causes it to vent through the fuel pipe line, and maintaining adequate pressure on the nozzle for feeding the fuel and upholding the same against the pressure in the trap chamber with adequate excess of pressure above the latter to keep the liquid moving on through the fuel pipe line to the carbureter.

It will be found convenient for maintaining uniform pressure on the carbureter to provide the little standpipe, 70, above mentioned, erected on the fuel pipe line extending to a height sufficiently above the carbureter to afford adequate gravity head for feeding the carbureter. This standpipe may have capacity for supplying the carbureter through any short interval of interruption in the feeding operation of the devices described which may occur from any cause; and to prevent the liabilityof overflowing this standpipe, it is capped at the upper end, and the cap, 71, is provided with a small vent aperture, 72, which is closed by a little cork, 7 3, which floats upon the top of the liquid in the standpipe and is thereby floated upto a seat on the under side of the cap, limiting the depth to which the standpipe can fill.

When the air-pumping device described-is to be used for operating a simple suction and force pump for feeding the fuel from the main tank, said suction and force pump device mayy consist of pipe and fittings as shown in Figure 11. The T-fitting 90, has its horizontal cross member provided with check valves, 91 and 92, one at each side of the upwardly-extending stem of the T, both opening in the same direction, one end of the cross of the T being connected by an elbow, 93, with the fuel pipe line, 54a, the stem of the T being connected with the air pipe line, 12, through which there is operating alternate suction and pressure due to the closing of the air inlet passage, 17, and the openmg of the by-pass duct, 40.

lIn view of the fact that the vacuum produced by the suction of the engine can never exceed fifteen pounds per square inch, and will seldom exceed twelve pounds, whereas the pressure produced in the pressure phase of the cycle of the cylinder which is connected may be many times as great, it may be found desirable to provide means for res tricting the pressure, leaving the suction unrestricted.

This may be accomplished by a simple form of check valve which may be interposed in the pipe-line, 3, at such -a point as indicated by the deflection, 100, (see Figure 1), said check valve device being illustrated in detail in Figure 14, consisting of a small disk, 101, seating downwardly on a horizontal seat provided at the upper end of an elbow, 102, in said pipe connection from the engine, the disk being checked as to opening by the opposite elbow Whose lower end has notches, 104, dimensioned for affording free movement of air toward the engine in the suction phase, the disk seating for stoppage of the disk in .the opposite direction during the compression phase, and having a central aperture, 105, which affords only very restricted path for the gas in said compression phase.

A preferred method and means of limiting the pressure transmitted from the engine without limiting the suction, consists in introducing a pressure-relief valve in the line anterior to the liquid piston; and for this purpose the duct, 23, leading to the pressurelimiting or safety valve, 24, is connected as described above, through the turn cock, 110, with the duct, 2. When the turn-cock is set for connecting the vent duct, 23, with the duct, 2, the function, of the safety valve for limiting the pressure developed beyond the liquid piston is in abeyance, but is rendered unnecessary because that pressure cannot exceed the pressure at the engine side of the liquid piston.

1. In a construction for the purpose indicated, in combination with a container constituting a fuel source, a fuel pipe line from the fuel source for supplying the carbureter of an internal combustion engine, a compressed air conduit discharging within the intake of the fuel pipe line; an air-trapping chamber on the fuel pipe line subsequent to the entrance of the fuel from the fuel source to said pipe line, the pipe line comprising a pipe member which leads on from the airtrapping chamber toward the carbureter opening for fuel intake at the lower part of said air-trapping chamber; whereby the tension of compression in said trapping chamber operates for driving the fuel on toward the carbureter, said trapping chamber having a pressure vent at the upper part and a yieldingly seated valve controlling said vent for limiting said tension of compresslon.

2. In the construction defined in claim 1, the pressure vent opening from the trapping chamber being connected for discharge of air within the fuel container; whereby vaporized fuel carried by the air may be recovered by condensation in the container.

3. In the construction defined in claim 1,

` foregoing, the pressure vent valve being spring-pressed for seating, and means for ad# justing the tension of the spring to limit at will the air pressure in the system operative for delivery of fuel to the carbureter.

4. In combination with the construction dened in claim 1, an air pumping device .for furnishing compressed air to the compressed air conduit having a pressure-limiting vent valve, and adjustable means for resisting its opening.

5. In a construction for the purpose indicated, in combination with a container constituting a fuel source, a fuel pipe line from the fuel source for supplying the carbureter of an internal combustion engine, a compressed air conduit discharging within the intake of the fuel pipe line; an air trapping chamber in the fuel pipe line subsequent to the entrance of the fuel source from said pipe line, the pipe line comprising a pipe member which' leads on from the air trapping chamber toward the carbureter opening for fuel intake at the lower part of said air trapping chamber; said :trapping chamber having a pressure vent at the upper part and a yieldingly seated valve controlling said vent, the fuel pipe line intake in the container being a Venturi tube, and the compressed air discharge conduit terminating as a nozzle for discharge of compressed air at the constriction of the venturi.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois, this 28th day of March, 1923.

CHARLES S. BURTON.

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