US2406120A

US2406120A - Venting means

Info

Publication number: US2406120A
Authority: US
Inventors: Emil O Wirth
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1943-07-17
Filing date: 1943-07-17
Publication date: 1946-08-20
Anticipated expiration: 1963-08-20

Description

Aug., z, 94@y E, Q www 2,406,12@

VENTING MANS Filed. July 17, 1945 7g l l L4 55. .I 32 f, 19.5 482 44a: 38

6 4 W w 68 l 4 55 ig l ll.: l l 70 d Y k 7/ u 50 33 I| 6o 5a 52 \26 INVENTOR @E BY Patented Aug. 20, 1946 UNITED, STATES PATENT Uiufm i dix'- Aviation Corporation, South Bend, Ind., a

' corporationof Delaware Application July 17, 1943, Serial No. 495,123

1 This invention relates to venting means and particularly Yto automatic pressure relief means for use in connection with fuel tanks or reservoirs of fuel supply systems. l

The invention is particularly useful as a vent Vfor the tanks of fuel systems, such for example as are used in aircraft, wherein the fuel is taken from the tanks by a fuel pump and delivered to the carburetor or other fuel proportioning device preparatory to delivery to the engine cylinder. Sincefuel, such as gasoline, is volatile, a portion of the fuel tends to vaporize and escape out of the tank vent, particularly at4 high` temperatures or low barometric pressures, with the resultant loss of fuel. Also, this tendency to vaporize causes the formation of vapor bubbles which to some extent remain entrained in the fuel and are notl released until agitated or subjected to a suddenly decreased pressure as may occur at the inlet' of the fuel pump. The vapor bubbles so formed 'tend to vapor-lock the pump, and if passed to the carburetor, tend yto interfere with its operation. 1

The above mentioned difliculties may be at least partially overcome by the use of any pressure type of relief or vent valve, whereby the fuel vapor pressure is utilized to maintain the tank under superatmospheric pressure whenever the fuel tends to volatilize. As the fuel may be of a highly volatile nature,'it is possible under various -well known conditions such as high temperature and/ or high altitude, to develop a high vapor pressure within the tank which may reach such a high value that there is danger of bursting the tanks. The vapor ventvalve must therefore be reliable in operation, and function to release vapor whenever the pressure 'in the tank exceeds avsafe value.

" -It is therefore an object of the present invention to provide a device for maintaining the fuel in a fuel tank under moderate superatmospheric pressure.

It is another object of the invention to'provide a device for the relief of excess vaporV pressure in a fuel system of this character and particularly of the pressure in the fuel reservoirs or tanks thereof. Y

It is still'another object of the invention to provide a device of this character that is adapted vto relieve the pressure of one or more such ytanks Still another object o-f theV invention is to pro- 3. Claims. (Cl. 277-50) 2 Y seat having an opening adapted to be closed 'by said ball, said other member being supported by -the diaphragm, the valve being adapted to accommodate considerable misalignment ,ofA said members.

A further object of the invention is to provide a device of this character having an auxiliary valve adapted to permit air to enter the tanks to compensate for the removal of fuel and/or yto compensate for the contraction of fuel which may occur under certain well known conditions.Y v

A still further object of the invention is to provide a device of this character having a check valve arrangement adapted to prevent the escape of fuel therethrough when inverted. f

The invention is further characterized by its simplicity, effectiveness and reliability, and by the means adapted to support the check valve when in its normal open position.

A further object of the invention is to provide a device of this character wherein novel improvements reside in certain details o-f construction and arrangements and Acombinations of the parts thereof.` I f The characteristics and advantages of the invention are further sufficiently referred to in connection with the following detailed descrip# Y Figure 2 is a vertical section through vsaid venting device which embodies the invention; and

Figure 3 is a plan view of the retainer ring for" the check valve.

Referring more particularly to Figure 1 the' fuel tanks or reservoirs are indicated generally a't I0. Fuel may be taken from the tanks through conduits I2, I4 and I6, conduits I4 and I6 preferably being provided with

valves

20 and 22 respectively. The upper portions of the tanks are connected together by a vent pipe 24 to which a venting device, indicated generally at 26 is attached. The venting device comprises a casing including a pair of

casing members

28 and 29 between which a exible diaphragm 30, which enlarged portion divided by the diaphragm into. an atmospheric chamber 38 and a pressure champ .f

ber 39, the latter being a chamber from which Y vapor under pressure may at times escapethrough 4 radius of the ring 18 but of sufficient length to engage and support the ball 14,

Operation In operation vapor pressure from the tanks I is conducted through the vent pipe 24 and passes into the pressure chamber 39 through a passage 86 in the nippley 36, The spring 56 is `so calibrated that when'the pressure in the lower portion of the chamber 38 reaches a predeter- '.mined value of, vfor example one or two pounds,

.or any other desired value, the pressure on the diaphragm V3l) forces said diaphragm upwardly a pressure outlet relief valve, `comprisii'ig amdvable valve seat member supported by 1thedia if phragm and comprising a body 4B having a cen-- tral opening 42 therein throughiwhichfsaid vapor may pass when the valve is open. The valve seat is secured in a central opening in the diaphragmV by clamping the latter between the -upper surface of the body 40, which isr of substantial area,l a-nd Ya; thin metal washer 44, secured in 'place' by tur-ning over the free end of a tubular ange46.. In order to vprevent the dia-phragm from being 'cut and injured by the peripheral edge of saidy washer and the adjacent edge of the. valve body-40 said washer edge-is turned outwardly-from the 'diaphragm 'at' 48 and the 'edge of the valve body 43 `is rounded. The Xed valvememberfof the pressure outlet valve comprisesA a ball adapted to close the opening 42 1in thel valve member 4t, said ball being received in a cup-like member 52 supported within the chamber 3`9'by Iintegral a-r-ms 54--whic-h extend between the cup 52 andthe interior wall of the casing :member 2-8; Thefree edgefportion` of the cup' 52 is pressed inwardly at 53 to engage the ball 50 andA secure same .in the e cup.` A spring v56, which reacts between the washer 44 and body 35er the check valve 34,'urgesthe valve member 46 into seating relation with the Y between said valveg member 68- and' a spring retainer 'H disposed within an enlargement ofthe f bore16l of plug66.

lThe check valve 34, which prevents escape of fuel through the venting device when inverted, includes a vent passage 'I2 in the body 35,.4 said passage taperingY inwardly towardv the atmospheric endv'and' having a valve seat 73' adjacent said end on which a ball va1ve`14`is adapted to seat when the device is inverted', at which` time the ball- -74 assu-mes the dotted line position 14a.

` However, whenthe device is in `its normali upright position the ball 'I4 is in thev full-line position in the lower portion of thevent passage 'lf2 and is supported insaid position by a, retaining memberfbest' shown in Figure 3, comprising `an annular ring portion 1:8 which is spl-it` at Sil-the free endsY of the ringY T8 being vspaced apart. to

Ypermit contraction of said ring for insertion in a groove provided therefor in a depending .annular flange V82 formed integral withL the body 35 ofvalve 1314;. Integral' with said ring are va, pluralty of radiallyextending valvesupporting arms 84 the length of said arfms'beingV less than the 'thereby' raising the vvalve member 40 from en- .gagemeniitvith the ball 50 and allowing vapor to escape throughjthe opening 42 into the atmoswpheric chamber 38 from -which it escapes to atmosphere through the vent passage 72. When .thepressure in the tanks drops below the value for which the spring 56 is calibrated said spring returns the valve seat member 40 to seating engagement with the balll50 vthereby Aclosing the vent, itbeing noted that the area of the .surface of ball 50 available to close the opening 4-2 of the valve seat is .suicienttoeiect closing' of said opening l42- though the valve seat may be tilted or considerably out of alignment relative to the axis of themain vent passage.

The by-pass is provided in the device to permit air to-y enter the tanks and compensatev for the withdrawal of vfuel under certain well known conditions, orto permit air to enter the tanks when the fuel cools down and contracts sufficiently to cause a partial vacuum in said tanks.

I nasmuch as it is undesirable for any substantial vacuumy to bebuilt up in the tanks the spring l0,

closing the ley-pass valve 68, isextremely llight, being onlyr of such strengthas to retain the valve in the closed position when the pressures .on

opposite sidesthereof arelsubstantially equal'so that as soon as a slight vacuum occurs in said tanks the by-pass valve opens and relieves the vacuum. Y

When the venting device is in its normal upright position the Yball 'I4 is supported by the radial arms-84 of ring 18 in such a position that vapor may pass sa-id ball and escape through the vent passage l2, but should the device be inverted they ball I4 will drop by -gravity tothe seat 13 and close the atmospheric vent passage y'l2 thereby preventing the loss of fuel therethrough should the weight of saidA fuel be sufcient* to open the pressure outlet valve.

While the invention has been shownrembodied in a fuel system having two tanks it is thought to Ybe obvious that said device may also b'eaused in a system having only one tank or in Aa system having three or more tanks. It is also thought that the invention and many of its attendant advantagesV will be understood from -the foregoing description, Yand though said invention has been illustrated and described in connection-with a single'embodiment thereof it will be apparent that various changes may bemade inv the form,

construction and arrangement of thepart-s'withmerely apreferred embodiment.

Iclaim: Y n 1. In a pressure control device for venting-'fuel tanks and the like: a casing comprising-a pair of {casing members,v said casing having Aajmain vent passage therethrough including an enlarged por"- tion.; a. diaphragm clamped between the casing members and separating the enlarged portion o the main passage into a pressure chamber and an atmospheric chamber; a xed valve member in the pressure chamber including a spherical segment portion; a valve seat secured to the diaphragm and having a valve passage therethrough adapted to be closed by the fixed valve member; a spring in the atmospheric chamber adapted to urge the valve seat to the closed position, said spring being so calibrated :that a predetermined pressure in the pressure chamber will eiect opening of the pressure outlet valve; a check valve including a body portion having a vent passage therein tapering inwardly toward the atmospheric end; Vand a ball valve adapted to seat adjacent the smaller end of said vent passage when the device1 is inverted; an annular groove adjacent the larger end of the vent passage; a split retainer ring received in said groove; inwardly extending radial arms integral with said ring and adapted to support the ball member when the device is in its normal upright position and permit the passage of fluid past said ball member; a by-pass connecting the pressure chamber and the atmospheric chamber; a vacuum valve in the by-pass for controllingr samesand relatively light yielding means urging the by-pass valve to the closed position.

`2. In a, fuel supply system including a fuel tank: a pressure control device comprising a hollow casing; a diaphragm separating the interior of the casing into a pressure chamber and an atmospheric chamber; an inlet passage communicating with the pressure chamber; a valve seat carried by the diaphragmand having an orifice therethrough; a fixed valve member in the pressure chamber, of generally spherical shape adapted to close the oriiice in the valve seat; yielding means urging the valve seat to the closed position withv a predetermined force; a by-pass between the pressure chamber and atmospheric chamber; a vacuum valve controlling the bypass; relatively light yielding means normally urging the vacuum valve to the closed position; a. vent passage between the atmospheric chamber and atmosphere; and a valve adapted to close said passage upon inversion of the control device, said valve being disposed on the atmospheric side of said rst and second mentioned valves, and when closed, shutting off communication between the inlet passage :and atmosphere.

3. In a pressure control device for venting fuel tanks and the like: a casing having a main passage therethrough including an enlarged portion; a diaphragm separating the enlarged portion of said passage into a pressure chamber and an atmospheric chamber; a xed valve member in the pressure chamber including a spherical segment portion; a valve seat secured to the diaphragm and having a ypassage therethrough adapted to be closed by the fixed valve member; yielding means adapted to urge the valve seat to the closed position; a vent passage connecting the atmospheric chamber with atmosphere, said passage tapering inwardly toward the atmospheric end; and a ball valve adapted to seat adjacent the smaller end of said vent passage when the device is inverted; a retaining member within the passage adjacent the larger end thereof; inwardly extending arms integral with the retaining member and adapted to support the ball when the device is in its normal upright position and permit the passage o1' fluid past said ball member; a by-pass connecting the pressure chamber and th atmospheric chamber; a vacuum valve in the by-pass for controlling same; and relatively light yielding means urging the by-pass valve to the closed position.

EMIL O. WIRTH.