US2358875A - Pressure release valve - Google Patents

Description

Sept. 26, 1944. T. E. NICHOLS 2,358,875

' PRESSURE RELEASE VALVE Filed July 29, 1941 2 Sheets-Sheet 1 Q Q N v H r N x TAM, M'cals.

' INVENTOK BY E M/ W ATTO IE Y.

p 1944- T. E. NICHOLS PRESSURE RELEASE VALVE Filed July 29. 1941 2 Sheets-Sheet 2 mm, E. Mew/ INVENTORf Patented Sept. 26, 1944 PRESSURE; RELEASE VALVE Thomas E. Nichols, Houston, Tex., assignor of one-half to Scott Red, Houston, Tex.

, Application July 29-, 1941, Serial No. 404,448

Claims. (01. 158-363) This application is a continuation-in partvof my previously filed application, Serial No. 244,259, filed December 6, 1938, for Pressure release valve.

This invention relates in general to pressure release valve and has for its general object the .provision of such a valve which may be employed in connection withthe fuel pump and carburetor;

or the like, of an internal combustion engine to prevent flooding of the carburetor, or the like,

. after the engine has been stopped, and to prevent I wastage of fuel.

- While this invention is applicable to any situation in whichthere is a fluid supply under pressure which is to be transmitted to a point of use where its flow is controlledby a valve, and it is desired to avoid leakage from the source of fluid under pressure past such valve during periods of idleness immediately following periods of use, this device is especially adapted for use in the fuel system of an internal combustion engine such as is commonly found in an automobile. j

In the ordinary fuel supply system used in automobiles, the fuel is fed by means of a pump, or some other suitable apparatus under pressure to the carburetor. Its flow into the carburetor is controlled by a float actuated needle valve. Most such fuel pumps furnish fuel at a pressure of several pounds per square inch more than is actually required to feed the fuel to the carburetor. Upon investigation of many cases of automobiles which were found to be hard to start after having been in operation but a short time before, I have discovered that the apparent reason 1 for such diflicult starting is that the fuel under pressure between the pump and the needle valve of the carburetor when the engine is stopped slowly leaks past such needle valve into the carburetor, thereby providing an excessive fuel supply and resulting in what is ordinarily termed flooding of the engine, which prevents it from being readily started. v p

It is a more specific object of this invention,

, therefore, to provide a means whereby such excessive pressure of fuel between the fuel pump and the needle valve of the carburetor may be relieved upon-stoppage of the engine and where-' by this may be accomplished without the wastage of fuel. I 7

It has also been found that the immediate source of fuel into the carburetor as a result of the starting of the engine and the opening of the needle valve often times causing flooding of the carburetor and causes the engine to stop almost immediately after it has started, and thereafter- 1 prevent it from being readily started again.

It is, therefore, another specific object of this invention to provide a device which will prevent the surge of an excessive supply of fuel into the carburetor immediately after the engine ,has started.

Other objects and advantagesof this invention will become apparent from the following description taken in, connection with the accompanying drawings in which isillustrated one embodiment of this invention.

In the drawings: 7 V

Figure 1 is fragmentary side elevation of a device constructed in accordance with this invention shown in theposition it occupies with respect tothe fuel pump and carburetor of an internal combustionengine such as is commonly used in an automobile.

Figure 2 shows a longitudinal cross-section through the valve illustrated in Figure 1. I

Figure 3 shows t a transverse cross-section through the same valve taken along the line 3-3 of Figure 2. 7 I

Figure 4 is a view similar to Figure 3, but taken along the line 44 of Figure 2. I

In Figure 1 there is, shown diagrammatically an engine I which may be the usual type of internal combustion engine employed in automobiles. The intake manifold of this engine is shown at 2 and the carburetor: is shown at 3 for supplying a proper fuel mixture to the manifold Th fuel is intended to be supplied to the carburetor by means of afuel pump 4, connected in the usual of the carburetor is customarily located a chamber having a float therein which controls the needle valve, closing the valve when the float rises and opening the valve when the float falls.

This serves to control the entry of fuel into the carburetor through the opening I.

' The device'o'f this invention is connected to the pump 4 by means of a pipe 8 and to the intake'openingl of the carburetor by means of l2 which is connected to the pipe 8 and the outanother pipe 9. It consists of a main body 'por tion In covered by a cover member H and having an internal structure such as will be presentlydescribed. In addition to the intake port structure of the device, as illustrated inFigures piston 2 I I this piston-being hollow for portion ofits length. butbeing-closed a -end-as shown 'at- 22. --Preier-ably,- this piston is The. piston 'is relatively close ing to prevent lea and number as the openings 20. *On' its outer municates directly with the lower end portion of the cylinder I8 .so that .f uel entering through the port I2 is discharged "directly into cylinder i8 10 at its lower end.

Adjacent its upper end the wall I1 is provided with a plurality of spaced radial openings 20 providing communication between the interior of the cylinder I8 and the annuIarspaceIB surrounding this cylinder. The cover member II may or may not close the upper end of the cylinder I8, this being immaterial to theoperation of the device. The only essential function of this cover member is to close the upper end of memher I0.

The outlet port I3-communicates directlywith the-annular spaceor chamber I Swithinthe member '-I 0 at a point spaced -somewhat-below the openings 20, but a considerable distance above ---the lower end: ofmember I I I].

- The opening I4 which is provided .for the rel-iefof. pressure, as willbe;-presently: described, extends through the annular space I 9. tocommunicate with the interior of-=the cylinder-I8 only ata point intermediatezthe-ends of this cylinder.

Slidablymounted-within the cylinder I8 is a the major t its upper v made with relatively thiokwallsso as to provide it with a substantial amount -of weight, -the amount ofweight provided however being de- -pendentupon-"the pressure "which is ordinarily- 4o provided by the pump, it beingobviousthat the weight of the piston should not be great enough to-interfere with the normal operation of- -the pump. Also, the opening through the piston -must, of course; be 'sufficiently' large so that it will be able'toallowifree passage of sufficientiuel to supplythe-carburetor under all conditions.

fitted within'the cylinder awith a fit, but isnot provided with pack- -kage about the piston.- For t'his reason, there may be a small amount of leakage past the piston at alltimes where there is sufiicient difierential 'pressure at two points on the i length of the piston to cause le'akage.

' Adjacentits upper end,'the piston is provided with a plurality of spacedradial openings 23 providing communication between the hollow interior of the piston and the exterior of the piston, and these openings are so positioned that when the piston is i cylinder I8, these openings 'Wi1l' on the same level as the opening 20 and the openn its" uppermost position withinthe be substantially ings 23 are made; of substantially the same size ing the various openings-23. Ihis isfor the purg thatwhenever the piston is in its ition there will be communication pose of insurin uppermost pos between thehollowinterior of the piston andtheoannular space 19 through the-openings-20 and 23 and the channel or-groove 24.

Intermediate its ends and belowthe openings --23- the piston is-provided with anotherv passage or opening :ZS proViding communication between its.

hollow interior and its exterior. There is also a circumferential groove in the exterior surface of the piston as shown at 26 on the same level as the opening 25. This groove and opening are so positioned that when the piston is in its uppermost position they will lie a substantial distance above the relief port I4, but when the piston has moved downwardly a substantial distance and ..the groove 24.; and the openings. 20 .no longer register, the. groove 26 and the relief port I4 will come into register, thus providing communication between the interior of the cylinder I8 and the piston 2I, and the relief port I4.

In operation, when the engine to which a device, .of .this ,kind is connected, is started, the pump will start; operating and will cause a build up of pressure below and within the piston 2|. -This- Will --tend to raise the piston M and this piston will move towards the top of the cylinder I8. As above stated, the upper end of the cylainder I 8..may.or maynot be completelyclosed by .thecover iI I 1If.=it.beassumedthatthe.upper'end .:.of the cylinder. :I 8.- is. closed: .by the mover; I. I then as. soon as the. upper; end :of .thaipiston. 2 I. closes the .port 20,- further .upward lmovementaohthe piston will be. accomplished as.leakage. takes place from above the piston. down-v around the piston and into the-portsiZlI. lnaiveryfewqseconds the piston-wi1l riseluntilthe ports 20and 23 register, whereupon fuel .will .flowthrough those ports. in whatever amounts may be required. During: this time before the ports register the-engine .may operate on =the..-fue1:-inthe carburetor-bowl. =At all times while the pump is running-there is, of course; aminute leakage past the piston-intothe port- I4 and thence back through the by-pass I 5 to-the pump'intake 4. Thisle'akage, however, -isso--sma1las to .be inconsequential during -the --operation of the engine.

' If-it be assumed-that the upper end of the cylinder I8 is-not closed by cover -I I-, theoperation would be--the-'same except thatthe piston could move completely to the --upper -end=of its travel without necessity for-leakage. A In' the event-the=engine should stop or' beshut --offand the needle -val-ve admitting fuel to the engine shouldfor'that reason,-or-any other-reason; be -closed-there will remain within cylinder l 8,the piston --2 I the chamben -I9',-and' -the l-ine "-9,--a quantity opium-under pressure. However, '-when the-engine is shut off-and stops as-it would beif the needle valve were closedforany reason, the pumpwill also stop.

T-hepresent invention has" forits purpose the provision of a meansivhereby under-those-circumstances the pressure existing within'thespace indicated. when the-"motor stops-lw-ill --be bled' off and by-passedbackto the. fuel supply so that it a will-not-becaused to leak past the' needle :valve into the carburetor, and cause -flooding--of the carburetor or wastage of fuel.

The device doesnot operate-"-to---relieve the .said...pressure instantaneously -when .the :motor stops. :However, when the motor stops-ithepressure in the chamber I 9 and tl-i'at-w-ithin' thecylinder I8 -being substantially-aequal; the piston ..will begin to move :downwardly under itsown weight as rapidly as leakage can take place from the upper edges of the port -23 upwardlyinto and through port 20. This leakage in itselfi w-ill of -course, not relieve thelpressure" either within the cylinder- I 8-orthechamber- I 9; but there may be some leakage; past J the piston into i the i port icI-fl which will somewhat relieve the pressure within these spaces :during this time. As soon as' the and'within the chamber I9 will be immediately *relieved as a substantial quantity of the fluid flowsv out through port I4 and as the piston 23 drops in consequence of such flow. This relieves the pressure on the needle valve of the carburetor so that as, the motor stands idle there will not be a leakage past this needle valve to flood the carburetor or to waste fuel. Instead, the pressure is relieved by bleeding the fuel back to the fuel supply and when it is again desired to start the motor, it will be found to be in perfect condition for starting with no flooded condition existing.

When the motor is again started, there will be a relatively small amount of fuel remaining within the carburetor bowl so that the motor may run until the piston 2| is forced upwardly to the point where the ports 20 and 23 come into communication with each other. The fuel in the chamber l9 below the ports 20 may be forced by the pressure of the rising piston to flow slowly into the carburetor during this period, but there cannot be an excessive surge of fuel into the carburetor, such as would cause flooding thereof.

In view of the foregoing, it will be appreciated that a means' has been provided for carrying out all of the objects and advantages sought by this invention.

Having described my invention, I claim:

1. In a device of the character described, a carburetor having a float operated needle valve therein for controlling the flow of fuel into said carburetor, a pump for supplying fuel under pressure to said carburetor, a body having a valve chamber therein connected at one point to the outlet of said pump to receive fuel under pressure'therefrom and at another point to the needle valve of said carburetor to supply fuel under pressure thereto, said chamber having a pressure relief port therein connected to the intake of said pump for relieving excessive pressure of fuel between said pump and said carburetor needle valve when said valve closes, and means in said chamber in the path of fluid under pressure flowing through said chamber from said pump to said needle valve and freely movable thereby toward the connection with said needle valve to a position covering said relief port to maintain said relief port closed, and said means being freely retractable away from the connection with said needle valve when no fluid is flowing through said chamber to open said relief port and relieve pressure of fluid throughout said chamber and on said needle valve.

2. A pressure release valve comprising a casing having a fluid outlet chamber adapted to be connected to a device utilizing fluid under pressure, said casing having an inlet fluid chamber adapted to be connected to a fluid pressure pump, said casinghaving ports to communicate said chambers, a piston type valve operating in the inlet fluid chamber between the inlet of the inlet fluid chamber and said communicating ports and movable toward said ports under the fluid pressure.

from the pump and having a groove having ports to register with the ports of the casing to open r 3. In combination with a pump and the carburetor of an engine, a presvalve when said valve moves away from said communicating ports.

fluid fuel pressure sure release valve comprising a casing having a fluid outlet chamber adapted to be connected to a float chamber of the carburetor, said casing havingian "inlet. fluid chamber adapted to be connected to the fluid fuel pressure pump, said casing having ports to communicate said inlet and outlet chambers, a piston-type valve movable in the direction of "fluid flow in the inlet fluid chamber under fluid pressure from the pump and having an outside annular groove therein having ports to register with the ports of the casing to open the chambers to each other upon such movement, a by-pass pipe connected to the fluid receiving side of the pump, said casing having a passage from said inlet chamber with the by-pass pipe connected thereto, said piston type valve having a part substantially closing said passage when said valve is in a position to open said inlet and outlet chambers to each other, and having a port movable to register with and open said passage upon cessation of fluid flow into said inlet chamber to permit by-passing of fluid from the fluid inlet chamber back to the receiving side of the pump.

4. In combination with a pressure fuel supply and the carburetor of an engine, a pressure release valve for fuel systems of internal combustion engines comprising a vertically arranged cylinder having an intake port in the lower end therepf and adapted for connection to the pressure fuel supply, a chamber arranged about said cylinder and having a port adjacent the upper end thereof and adapted for connection to the carburetor, said cylinder having ports adjacent the upper end thereof to communicate the cylinder with said chamber, a bypass means connected to said cylinder below the ports of said cylinder and adapted to be connected to the fuel supply, and a gravity influenced piston-type valve slidable in the cylinder and movable in the direction of flow by the differential between the pressure of the fuel supply and the pressure of fuel in said chamber to open the ports of said cylinder and to close the bypass means so as to permit fuel to flow to the carburetor, and movable by gravity to automatically. close the ports of said cylinder and open said bypass means when the flow of fuel to the carburetor is stopped by the closing of a fuel float chamber thereof causing a back pressure of fuel in said fuel chamber which equals the pressure of fuel from the fuel supply.

5. A pressure release valve for fuel system; of

internal combustion engines comprising a vertically arranged cylinder having a fuel inlet port in the lower end thereof adapted for connection to a pressure fuel source, a chamber formed on said cylinder and surrounding the vertical walls of the cylinder and having a port adapted for connection to a carburetor of an engine, said cylinder having ports adjacent the upper end thereof to connect the chamber therewith, said cylinder having a bypass passage located substantially intermediate the ends thereof and extending through the chamber with noncommunication therewith and adapted to be connected to the fuel source for the return of fuel thereto, and a piston slidable in said cylinder between said fuel inlet port and the ports adjacent the upper end of the cylinder and said piston being influenced by gravity, and having .:ports adjacent the upper Vendrothezeof, and said piston being movable underiz difienentialinf :pressure between :said ivcylinder ;and said :ohambe!" 1130 align the :ports ;of "the :pistonvmith :;the

morts adjacent the zupper aend. of the icylinder,

,whenthere is a-flow .dfzfuelzfromithessource 50f athe carburetorandsaid piston aheing adapted :to be moved :by :gravity i170 .imoveiahe pontsndf :the piston out of -:alignmentwith :.the ;ports eof gamma 5:; ing ,a mortzto align with the bypass ,passage when said :piston lowers :to close the ports .of said :cyi- 1inder; -and thereby permit return :of the :fuel ,to theisoureeefitom "the cylinder.

THOMAS E; FNICHOIJIS.

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