US2826043A

US2826043A - Pressure operated vapor-liquid selector valve for l. p. g. fuel systems

Info

Publication number: US2826043A
Application number: US370819A
Authority: US
Inventors: Howard E Simonson
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1953-07-28
Filing date: 1953-07-28
Publication date: 1958-03-11
Anticipated expiration: 1975-03-11

Description

March 11, 1958 H. SIMONS'ON 2,826,043

PRESSURE OPERATED VAPOR-LIQUID SELECTOR I VALVE FOR L. P. G. FUEL SYSTEMS Filed July 28. 1953 2 Sheets-Sheet 1 FIG. 2

FIG.

INVENTOR. H.E.SIMONSON ATTORNEYS 1958 H. E. SIMONSON 2,826,043

PRESSURE OPERATED VAPOR-LIQUID SELECTOR VALVE FOR L. P. c. FUEL SYSTEMS v 2 Sheets-Sheet 2 March 11,

Filed July 28, 1955 I N a x I 7 8 I; 0L I I 5, "I 1' I l! INVENTOR.

H.E.SIMONSON ATTORNEYS Unite 2,826,043 PRESSURE, OPERATED NAPGR-LIQUID SELEC- Appliwfitm y 19 3, S th! N 7 19 21 Claims. (Cl. 62i-1) This invention relates to internal combustion engine operations. in one aspeet it relates to an improved apparatus for use with liquefied petroleum gas an an internal combustion engine fuel. In another aspect it relates to a 'liquid-vapor selector valve for the selective withdrawal of liquid and vapor inresponse to tank pressures for maintaining tank pressures at minimum.

An object ofthis invention ist'o provide an apparatus for controlling the pressure of liquefied petroleum gas fuel in internal combustion engine fuel tanks when the engine is powered with liquefied petroleum gas.

Another object of this nventionis to provide an apparatus for use in maintaining relativelylow pressures in liquefied petroleum gas automotive fueltanks under atmospheric and road temperatures.

Another object of my inventionis to provide an apparatus for use in maintaining relativelylow pressures in liquefied pe roleum gas fuel tanks under high temperature operating conditions which apparatus issimple and inexpensive to make, and safe. and reliable in operation.

Yet another object of my invention isv to provide a vapor-liquid selector valve for usewith LPG tanks which may be subjected to comparatively, wide variations in ambient temperature, such as encountered in the operation of trucksand buses.-

Still other objects-and advantages of my invention will bev obvious to those. skilled in theqart upon reading the followingspecification and drawing, which respectively describes and; illustrates preferred: embodiments of my invention.

T hetern s Liquefied Petroleum Ga-sfi and LPG as used hereinbelow refer to.- comrnercial liquefied petroleum gas, suchas commercial, propane. gas includes, in addition to propane, such other hydrocarbons as butane, isobutane, isopentane; and th like. While one or more of these other hydrocarbons may be present in the commercial propane or liquefied petroleum gas they are ordinarily present in relatively small amounts. However, they may be present in appreciable amounts but ordinarily commercial propane contains largelypropane. The presence of any of these other-hydrocarbons in propane exerts atleast some efiect on the vapor pressure of propane,- suchelfect however beingsmall when the concentrations of theseother, hydrocarbons are small. Such.

l ht fi s swi hs es rs ilts 1 qqm ci p op i h-sw ms ma ssut sq thsse other lower vapor pressure hydrocarbons; are neglig-ible and the vapor pressure of commercial propane. orliquefied petroleum gas will hereinafter bereferredto merelyia-sthe vapor pressure o'fpropane orof-liquefied'petroleum gas.

Since the. vapor pressure of commercial propane is about 200 lbs. per sq. in. at 100 F. the use of relatively heavy pressure fuel tanks is necessary. At temperatures higher than 100 F. which temperaturesare sometimes encountered during certain seasonsoffthe year, propane has still higher vapor pressures thanthe. above mentioned 200 lbs. Thus, the utilization of this liquefied fuel under Liquefied petroleum- States Patent suchtemperature and pressure conditions becomes a problem requiring-careful consideration.

According to myinvention I have provided a pressure operated liquid-vapor seleetor valve in which a pressure operated motor actuates a piston for selecting vapor or liquid for withdrawal from the tank. When the pressure in the tank is relatively lowthe motor operates the piston to close off a port leading to the vapor containing portion of the tank and opening a--portleading to the liquid containing portion of thetank for removal of liquid, 0pm: plemen'tarytothis when pressurein the tank is highthe motor operates the piston-to close ofi the port leading to the liquid containing space and opening the port leadingto the vapor containing-space of the tank thereby permit ting Withdrawal of vapor, Which-operationis followed by evaporative cooling and ultimatereductio-n of pressure. My apparatus can be inserted into an-LPG tank through a single opening, and for the. most part themajor portion oi the liquid-vapor selector valve is disposed Within the tanks-thereby minimizing danger fromdamage to the valve.

In the drawing: Figure 1 is a longitudinaliviewpartlyin sectionof one embodiment of myinvention.

Figure 2, is a longitudinal. View, partly in section-of;

another embodiment of my invention.

Figure; 3- is a sectional viewof anendplate useful Withthe apparatus embodimentofe Figure 2 Figure 4 is alongitudinal view, partly insection, of still another embodimentofi my invention.

Figure 5 is a diagrammaticview of the. liquid-vapor selector valve assembly of; my invention in conjunction with an autornotive fuejl system.

Figure 6 a longitudinal sectionalviewv of a portion of. the apparatus of Figuresd, 2, 4; and 8.

Figure 7 "is a longitudinal-view, partly insection, of'a iw ith pp ratus of F gu 5 u a on ud na apparatus for use in conjunction with a portiomofr the apparatus. of Eigure 4.

Referring-now to the-drawing and-specifically to Figure 1, this vapor-liquid selector:valve eonsists-of a cylindrical" housing member ll containing a movable-piston 1 3; To-

this, piston, is attacheda piston rod 17 which in turn-isconnected, to a pressure/ 1 operative, motor-- 15. ThiS- P IIS'1. sure operative; motor in the embodiment of Figure 1 is: illustrated; asratpressure opfilative bellows. This-bellows; is provided with a compression spring19. for assisting. This llows s. s, e tioned ab at p ssure sspqnsiv f ellows and it is.pr er hly=at eastp r i l y evasuat da o thebellows, to expandupon reduction ot'pressu ei minimize the effect of temperature changes. This hel-g lowsis supported by a base 151316221: whichforms the end wall of, tho-cylindrical. housing 11. A port 27 is; pro-.

vided inthe upper s de Wa-lLhousing 11 for; admittance;

or fuel vapor While another port 23 is provided as shown, To. thisport 2 3; is attached a diptl be 29 which isintended;

to dip into liquid fuel in tank 37. A- conduit 25 is dis p s d hr ghout. he ength of p n. 13 o p s asewq qu from p ce be ow he p ton-tome pa e. ab e. the piston. The upper endpof the housingme nber 11;.

is provided with a flange 12 for installation purposes.

Bolts 33 hold fian ge 12 rigidly againsta ring 3 5 wh ich in turn is welded or attached otherwise to the walls of,

the tank 37;. Element 31 is an excess flow valveof moreor less conventional type.

In the operation of the apparatus embodiment illustrated in Figure 1 whenpressure within the tank increases,

to a value higherthan a preselected pressure the bellows 15 tends to. contract thereby lowering piston 13 to close port 23 and open port 27. Vaporous LPG fuel enters the: housing 11' bypwayiof port 27 and passes-through the excess;tlowvalvafikfor useiins the engine. Whenpres- 1 view, partly in section, of-

asaaoes sure within the tank 37 decreases to a value below said predetermined pressure the bellows expands with the assistance of the compression spring 19 thereby raising piston 13 to close port 27 and open port 23. Under this condition the source of the vaporous fuel is closed off and liquid fuel may be admitted through dip tube 29 and port 23 into the housing 11 below the piston 13. This liquid then flows upward through conduit and through the excess flow valve 31 to the fuel conduit.

In Figure 2 of the drawing reference numeral 47 identifies a selector valve housing provided with a piston 49. A tubular piston rod 51 is fitted into piston 49 so as to provide a passageway from the space at the bottom of thehousing 47 to the space above the piston. An end plate 61 closes the lower end of the housing 47. Centrally disposed on the top surface of this end plate is a resilient sealing member 63, such as a hydrocarbon-proof synthetic elastomer. The bottom end of the tube 51 is intended, to act as a valve for seating against the sealing member 63 when the piston is at the lower end of its extent of travel. Tube 65 is provided. for dipping into liquid fuel in the tank and through which liquid fuel is drawn into the selector valve. A pressure operative motor is illustrated in Figure 2 as a pressure operative bellows. This bellows is also provided with a compression spring 55 for assisting expansion under reduced pressure conditions. A circular plate 57 is attached to the upper end of the bellows and to the tube 51 in such a manner that as the bellows expands or contracts piston 49 moves respectively upward or downward. An annular plate 59 serves as a base for the bellows 53 and this base is attached rigidly to the housing member 47 as'illustratecl. A port 67 is provided in the upper side wall of housing 47 for inlet of vapor. A flange is provided for use of bolts 43 for attaching this assembly to ring 41. This ring may be attached rigidly to the tank wall 39 by any method desired, such as by welding. An excess flow valve is provided for controlling the outlet of fuel from this selector valve, i. e., the excess flow valve closes ofl entirely the flow of fuel in case of breakage of the fuel line.

By the use of the liquid dip tube 29 of Figure 1 and dip tube of Figure 2 the respective valve housings may be relatively short since the dip tubes are intended to be sutficiently long to extend substantially to the bottom of the fuel tanks. Under some conditions it might be desirable not to use a liquid dip tube. The end plate 69 of Figure 3 can be inserted into the lower end of housing 47 of Figure 2 in place of end plate 61. This end plate 69 is provided with one or more openings 71 for admission of liquid into the housing. A resilient hydrocarbon-proof seal 73 is provided for sealing the bottom end of tube 51 against inlet of liquid when piston 49 is at the lower end of its extent of travel. When using the end plate 69 of Figure 3 in place of end plate (61'and dip tube 65) the cylindrical housing member of the selector valve must be sufliciently long that the end plate 69 is positioned at a level very near the bottom of the tank. The openings 71 merely replace the dip tube 65 of Figure 2 for inlet of liquid. Otherwise the construction and operation of the selector apparatus With end plate 69 is similar to a construction and operation of the embodiment of Figure 2.

In Figure 4of the drawing this embodiment of selector valve includes a housing member 91 intended to be installed within the tank 99. A housing member 75 is disposed outside of the tank and a flange-102 integral with housing 75 is held by bolts 103 to ring 101 which in turn is fastened, for example, by welding to tank Wall 99. To the outer end of the exterior housing 75 is provided a diaphragm 79. This diaphragm is held in place by a bonnet 77 and bolts 107. An excess flow valve is provided in the bonnet 77 for closing off this apparatus to the escape of fuel in case of rupture of diaphragm 79.

This excess flow valve is also intended to serve as a pressure equalizing vent to maintain the space under the bonnet and above the diaphragm at atmospheric pressure. However, in case of rupture of diaphragm 79 and admission of high pressure gas to the space under the bonnet this excess flo'w valve prevents escape of combustible fuel. A compression spring 83, adjustable by a spring adjuster 81, is provided for assisting movement of piston rod 87 and piston 89. A shoulder 92 is provided in the upper part of the housing 91 to prevent expulsion of piston 89 in case of accidental breakage of the exterior housing member 75. An excess flow valve 105 is also provided for controlling outlet of LPG from this selector valve to the engine.

An end plate 93 is provided in the bottom end of interior housing 91. Piston 89 is provided with a conduit 109 for passage of liquid from the space below the piston to the space above the piston. An excess flow valve 108 is disposed in conduit 109 for closing olf fluid flow in case of accidental rupture of the exterior housing 75. In case of accidental breakage of housing 75 piston 89 will be immediately forced upward against shoulder 92 and excess flow valve 108 will then operate to close off all flow of fluid from the tank to the rupture area. A port 95 is provided in the inside housing member 91 as shown. A liquid dip tube 97 is provided for passage of liquid from the liquid containing space of the tank into the selector valve as shown.

, In the operation of the selector valve of Figure 4 when the pressure within the tank .has been decreased to a value below a predetermined pressure the diaphragm 79 with the aid of spring 83 forces the piston 89 downward to close the vapor inlet port 95 and open port 96 for inlet of liquid fuel. Under these conditions liquid will be admitted through dip tube 97 into the space above the piston 89 and this liquid will then flow upward into the housing 75 and outward through the excess flow valve to the fuel conduit.

When the pressure in tank 99 increases to some predetermined pressure the diaphragm 79 will be forced upward to move piston 89 upward to close the liquid admission port 96 and to open the vapor inlet port 95. Under this condition vapor is admitted through port 95 to the space below the piston. This vapor will then flow upward through conduit 109 and excess flow valve 108, that is, through the piston, and out through excess flow valve 105 to the engine. Removal of vapor in this manner continues until the liquid contents of the tank have been sutficiently cooled by evaporation that the pressure decreases to operate the diaphragm and piston assembly to close ofl the vapor and open the valve for removal of liquid.

in the embodiments of my invention the several pistons may under some conditionsv remain in an intermediate position allowing removal of both vapor and liquid simultaneously from the tanks.

In the embodiment of my invention illustrated in F1 gure 4 the pressure responsive motor is illustrated as a spr ng loaded diaphragm. A spring loaded bellows, respons ve to pressure, may be used in place of the spring loaded diaphragm. In Figure 8 of the drawing is illustrated a bonnet member 162a provided with a pressure operative bellows 163a. To the lower end of this bellows is attached a piston rod 165:: which is equivalent to piston rod 87 of Figure 4. An excess flow valve 167 is provided in bonnet member 16211 for control of fuel to the engine. In this case when pressure under bonnet 162a decreases to below a predetermined value bellows 163a, which is spring loaded, expands to lower the piston, not shown, and admit liquid for passage through valve 167 to the engine. When pressure under bonnet 1621: increases to above a predetermined value bellows 163a contracts raising a piston, not shown, thereby closing 01f liquid and opening the valve to the inlet of vapor.

valve 85 does not pass fuel to. .the engine. Excess flow 10a valve 108 ofFigure 4 can be similartothe valve illus trated in Figure 6 but there need not bea hexagonshaped section. 147 (Figure 6) .since valve .108 .isthreadedto the conduit 109. The valveof Figure 6 isprovided withia hexagon shaped section 147 for. useof-awrench. This valve is provided withra compression-spring. 151 and. a valve member 149, which members are held .in place by afitting 153 threaded at 159. ThreadslSS .are for in:- stallation of the. valve, while threads. 156 are for fasten. inga flow line for carrying fuel: from thevalve:

Figure 7 of the drawingillustrates in diagrammatic. torn-ran atmospheric shut-off valve which is intende-dto operate .in such. a manner that whenthe engine is: not. running the -valve' automatically .closes .the fuel .carry ing.

line againstcontinued passage ofinfl'ammable-fuelr. This.v 25.;

valve assemblyidentified by reference numeral 140-contains a diaphragm 163. Space under the diaphragm. is vented through a vent 165. Diaphragm163. is connected toa valve 161- inline 138* This line 138 isthefuel-inlett line to the valve :while conduit 141is the fuel-outlet linc. 0

The fuel outlet .lineldl ismof course connectedatothe carburetor and when pressure within. line- 141 i decreases,:'. as byturning over of the motor-instarting, pressure above diaphragm 163 decreases and" the diaphragmopens valve.

161. to permitpassage of fuelto thecarbureton Ob viously during times when .the engine isrunningpressure in-line 141 is below atmospheric and thediaphragm holds. valve161-open. When the engine is stopped pressure in line 141- becomes atmospheric and the. diaphragm 163 aidedby springp162 closes valve '161.

In Figure .5 ofwthe-drawing is illustrated; diagrammatically, a complete supply apparatus for-an internal com-. bastion engine using liquefied petroleum gas as fuel. A- pressure storage tank ill'contains the fuel, reference-nu meral- 115- identifying the liquid in the tank' and ref- 4.5 erence numeral 117 the vapor space above the liquid. Element 119 is a valvedconduit for filling of the-tank. A relief valve 121 is providedin case pressurerelief is required. Reference numeral 113 .identifies a selector-.-valves.. assembly of my invention 123 is intendedto be connected to the assembly 113.bymeans of such an excess flow valve asvalve 31.or-valve 45. Line or'conduit 123 discharges into .a-.filter element l25-for removal of foreign matterfrom the-,fuel. Fuel free from foreign matter leaves the filter and. flows .55

through conduit 127 to a pressure regulator 129. This pressure regulator is intended to reduce pressure. from tank pres-sureto such a pressure that one additional stage: of pressure:reduction is' sufficient. Apparatus131ris a. fuel vaporizer for making certain that only vaporous-fuel reaches: the carburetor. Conduit 133" conducts. waterfrom the automotive cooling systemtto the vaporizenwhile: conduit-135 conducts usedv water back tothez cooling sys.-- tern. Vaporous fuel leaves the vaporizer through 'acon- Y duit 137- and passes through a. final, pressure regulator... 139 which is intended to reduce the pressure to.substant-. tially atmospheric. From this latter regulator. fuel .flowsthroughconduit 138 to a valve assemblyJ'40from-Which the fuel passeson through conduit14-1 to a-carburetor143- and iutakemanifold 145. This assemblyof fuel dispense ing. andhandling apparatus-is such. as will be :used on automotive equiprnent such as trucks or buseseor even. auto.- mobiles-in caserthese latter vehicles would beppweredby liquefied petroleum. gas. Also sucht fucltdispensing and pressurecontrol equipment is suitable for useawith permas 75' disposed-inthe .tank. Conduit 50* nent. internal. combustion engines such.as.:those used. in: power plants, compressor. plants andthelikc,

While theselectorvalves describ.ed.hereinaft,er. have; been of the. top tank outlcttype, it is within the scope. of my. invention to adapt the hereindisclosed selector ,valve apparatus-to bottom outlet type fuel tanks. In this .case, thefuel outlet. enters the bottom of thetank. Liquid, would enter the port next. the tank-outlet while the, dip. tube wouldbe a gas dip tube-and would extendv upward into the vapor space of the .tank.

Materials of construction may beselectedfromamong those commercially available and adapted for. use in such. applications. It is preferable to use materials not easily corroded-by oxygen and/or moisture.

While certainembodimentsof myinventiorl have been,

described for illustrative purposes, the inventionobvious'lyg is not limited thereto.

I claim:

1. Aliquid-vapor selector valve assembly for use in, liquefied petroleum gas fuel systems comprising, in com bination, a valve body member, a portion of said valve body member being adapted to be disposed within a tank, said valve body member defininga first. conduit, a pres: sure operative motor in said first conduit, said pressure, operative motor being responsive to externally applied pressure, a movable piston driven by said motor-in s'aid conduit dividing said first conduit into two chambers, a. second conduit in said piston providing fluid communca: tion between said chambers, a port .inthe wall, of said body member for inlet of vapprous fuel, a port in ,the Wall of said body member for inlet of liquid fuel,.said portsbcing dis'pose'd'in the portion of said valve bodymember. adapted to be disposed in a tank, saidinovable pistonbeing. disposed in. general intermediate said ,ports' .andin, such a. manner that upon movement to one .end of its stroke one port becomes closed andthe otherport opened...

and at the other end ofits stroke said oneport becomes opened and'said, other port becomes closed and an outlet means at least near the outlet end of the valve. assembly.

2. In the liquid-vapor selector valve assembly offclairn,

1 wherein said outlet means comprises an excess, fiow valve assembly.

3. In the liquid-vapor selector valve assembly of claim.

1 wherein said motor is a pressure operative bellows.

4. A liquid-vapor selector valve assembly foruse in. liquefied petroleum gas fuel systems comprising, in com bination, a housing member, aportio'n ofsaid housing; member being adapted tobe disposed ,withina tank, a

pressure operative motor in said'housing member, said...

pressure operative motor beingresponsive to,externally applied pressure, a movable piston driven, by saidmotor in said housingmember dividing the space within said, housing member into an upper chamber and alOWcr, chamber, a conduit throughout the length of said piston providing communication. between said, chambers, a; first port in the wall of said housing member for inlet, of vaporous fuel, a second port in the wall of jsaidhous ing member for inlet ofjliquid fuel, said portabeingdis:

posed at different levelsand being in .theportionof said, housing member adapted 1 to.be dis'p ose'd jin saidstank, said "piston beingdisposed in general intermediate saidl ports and in such. a manner that upon-movementtothe, upper end of its stroke the upper portisclosedjand the lower port is opened, and'at the lower end'ofits stroke. theupper port is opened and the lower port isclosed, andlan outlet meansin said housing m ember atrleast. near the upper end thereoffor outlet ,of fuel,

5. In the liquid-vapor; selector valve.v assembly of .clairn 4. wherein said outlet means. comprises an, excess flow valve. assembly.

6. Inthe liquid-vapor selector valve assembly of clairn- 4 wherein. said: motor. is a pressure-operative.bellows;

7,. A liquidsvapor selector; valve. assembly forg use: in.

liquefied petroleumgasfuel systems comprising, in combination, ,a generally cylindrical, housing member, said housing memberbeing adapted for installation in the top of aliquefied petroleum gas storage tank and so disposed that the axis of said housing is at least approximately vertical, an end plate in the bottom end of said housing member, an opening in said end plate, a liquid dip-tube disposed in said opening in said plate and providing communication from the liquid containing space in said tank to a space above said end plate, a resilient sealing member attached to the top center surface of said end plate, a piston in said housing member adapted for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit throughout the vertical length of said. piston, said tubular piston rod being connected with the walls of said conduit in said piston and extending downward through said bellows to a level adjacent said resilient sealing member, the lower end of said tubular piston rod being adapted to seat against said resilient sealing member at the lower end of the stroke of said piston, a port in the wall of said housing member at a point above said piston when at the bottom end of its stroke, an excess flow valve in the upper end of said housing member, and means for attaching the outer end of said excess flow valve to a conduit for passage of fuel to a point of use.

8. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, in combination, a hollow housing member, said housing memher being adapted for installation in the upper wall of a liquefied petroleum gas fuel tank and so disposed that the axis of said housing is at least approximately vertical, a non-perforate end plate in the bottom of said housing member, a pressure operative bellows disposed on the top surface of said end plate and within said housing member, said pressure operative bellows being responsive to externally applied pressure, a movable piston in said housing member, a piston rod connecting said piston and said pressure operative bellows, a first port in the sidewall of said housing member at a level just above the top surface of said piston when said piston is at the lower end of its extent of movement, a second port in the sidewall of said housing member at a level just below the bottom surface of said piston when said piston is at the upper end of its extent of movement, a liquid dip tube extending from said second port to a level near the bottom of said tank, an excess flow valve in the upper end of said housing member, said excess flow valve being adapted to control flow of fuel from said tank, and means for attaching said excess flow valve to a conduit for passage of fuel to its point of use.

9Q A liquid-vapor selector valve assembly for use in a liquefied petroleum gas fuel system comprising, in combination, a housing member, said housing member being adapted to be attached to the upper wall of a liquefied petroleum gas fuel tank and so disposed that the axis of said cylindrical housing member is at least approximately vertical, a perforate end plate in the lower end of said housing member, said housing member being adapted to extend substantially to the bottom of said tank, a resilient sealing member attached to the top surface of said end plate, a piston in said housing member adapted for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit throughout the vertical length of said piston, said tubular piston rod being connected with said piston and extending downwardly through said bellows to a level adjacent said resilient sealing member in such a manner as to provide a passage from a level below' said bellows to a level above said piston, the lower end of said tubular piston rod being adapted to seat against said resilient sealing mom-- her when said piston is at the lower end of its extent of movement, a port in the cylindrical wall of said housing member at a level just above the top of said piston when said piston is at the lower end of its extent of movement, an excess flow valve in the top of said cylindrical housing member, said excess flow valve being adapted to control flow of fuel from said tank, and means for attaching said excess flow valve to a conduit for passage of fuel to its point of use.

10. A liquid-vapor selector valve assembly for use in a liquefied petroleum gas fuel system comprising, in combination, a housing member, said housing member being adapted to be attached to the upper portion of a liquefied petroleum gas fuel tank with at least a portion extending into the tank, said housing member being so disposed that its axis is approximately vertical, a movable piston inthe portion of said housing member adapted to extend into said tank, the bottom end of said housing member being closed, a pressure operative motor in the portion of said housing member adapted to be outside of said tankpsaid pressure operative motor being responsive to externally applied pressure, a piston rod connecting said motor "to said piston, an excess flow valve in the wall of said' 'housing member adapted to be outside of said tank and below said motor, means for attaching the end of said excess fiow valve outside of said housing member to a conduit for passage of said fuel to its point of use, said excess flow valve being adapted to control the flow of fluid from said housing member to said conduit, a vapor inlet port in the sidewall of the portion of the housing member adapted to be inside said tank and at a level just below the bottom surface of said piston when said piston is at the upper end of its extent of travel, a liquid inlet port in the sidewall of the portion of said housing member adapted to be inside said tank and at a level just above the top surface of said piston when at the lower end of its extent of travel, a liquid dip tube extending from said liquid inlet port into the liquid containing portion of said tank, and a conduit through said piston connecting the space above the piston with the space be low the piston.

11. In the liquid-vapor selector valve assembly of claim 10 wherein said pressure operative motor is a pressure operative diaphragm disposed gas-tight against the upper end of said housing member outside said tank, a bonnet disposed gas-tight on the side of said diaphragm opposite said housing member and an excess flow valve in said bonnet to regulate gas pressure in the space bounded by said diaphragm and said bonnet.

12. In the liquid-vapor selector valve assembly of claim 10 wherein said pressure operative motor is a pressure operative bellows.

13. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, in combination, a valve body member of generally circular crosssection, means for attaching said valve body member vapor-tight to the wall of a tank, a portion of said valve body member being adapted to be disposed within said tank when said means is attached vapor-tight to said tank, said valve body member defining a first conduit, a pressure operative motor in said first conduit, said pressure operative motor being responsive to externally applied pressure, a movable piston driven by said pressure operated motor in said first conduit dividing said first conduit into two chambers, a second conduit in said piston providing fluid communication between said chambers, 21 port for inlet of vaporous fuel and a port for inlet of liquid fuel in the wall of said portion of said valve body member adapted to be disposed within said tank, said movable piston being disposed in general intermediate said ports and in such a manner that upon movement to one end of its stroke, one port becomes closed and the other open and at the other end tof its stroke, said one port becomesopened andsaid other portbecomesblosed, and an outlet means at least near the outlet end of said valve assembly.

- 14. A liquid-vapor selector valve assembly for use .in liquefied petroleum gas fuel systems comprising, in com bination, a generally cylindrical housing member, said housing :member being adapted-for installation :in the upper portion of a liquefied .petroleum gas storage tank, an end plate in the bottom end of said housing member, an opening in said end plate, a liquid dip-tube disposed in said opening in said plate and providing communication from the liquid containing space in said tank to "a space above said end plate, a resilient sealing member attached to the top surface of said end plate, a piston in said housing member adapted for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit throughout the length of said piston, said tubular piston rod being connected with the wall-s of said conduit in said piston and extending through said bellows to a level adjacent said resilient sealing member, a lower end of said tubular piston rod being adapted to seat against said resilient sealing member at the lower end of the stroke of said piston, a port in the wall of said housing member at a point above said piston when at the bottom end of its stroke, and means for attaching the outer end of said assembly to 'a conduit for passage of fuel to a point of use.

15. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, in com bination, a housing member, said housing member being adapted for installation in the upper portion of a liquelied petroleum gas fuel tank, a pressure operative bellows supported by the inner end and within said housing member, said pressure operative bellows being responsive to externally applied pressure, a movable piston in said housing member, a piston rod connecting said piston and said pressure operative bellows, a first port in the side wall of said housing member at a level above the top surface of said piston when said piston is at the lower end of its extent of movement, a second port in the side wall of said housing member at a level below the bottom surface of said piston when said piston is at the upper end of its extent of movement, a liquid dip-tube extending from said second port to a level near the bottom of said tank, and means for attaching the upper end of said assembly to a conduit for passage of fuel to its point of use.

16. A liquid-vapor selector valve assembly for use in a liquefied petroleum gas fuel system comprising, in combination, a housing member, said housing member being adapted to be attached to the upper portion of a liquefied petroleum gas fuel tank, a perforate plate in the lower portion of said housing member, said housing member being adapted to extend substantially to the bottom of said tank, a resilient sealing member supported by the top of said end plate, a piston in said housing member adapted for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit throughout the vertical length of said piston, said tubular piston rod being connected with said piston, and extending through said bellows to a level adjacent said resilient sealing member in such a manner as to provide a passage from a level below said bellows to a level above said piston, the lower end of said tubular piston rod being adapted to seat against said resilient sealing member when said piston is at the lower end of its extent of movement, a port in the cylindrical wall of said housing member at a level above the top of said piston when said piston is at the lower end of its extent of movement, and means 10 for attaching ?the "upper portion-:of :said assembly to :a conduit for passage offuel to-its point of use.

17. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, incombination, a housing member adapted to be attached to the upper portion of a liquefiedpetroleumgas fuel .tank with at least a portion extending into said-tank, a-movable piston in the portion-of said housing member adapted to extendinto said tank, a pressure operativemotor in the portion of said housing member adapted to be outside of said tank, said pressure operative motor being responsive to externally applied pressure, a piston rod connecting said motor to said piston, means for attaching the portion of said housing member outside said tank and below said motor to a conduit for passage of said fuel to its point of use, a'vaporinle't port-inthe sidewall of the portion of the housing member adapted to be inside said tank and at a level below the bottom surface of said piston when said piston is at the upper end of its extent of travel, a liquid inlet port in the side wall of the portion of said housing member adapted to be inside said tank and at a level above the top surface of said piston when at the lower end of its extent of travel, a liquid dip-tube extending from said liquid inlet port into the liquid containing portion of said tank, and a conduit through said piston providing communication between the space above the piston with the space below the piston.

18. In the liquid-vapor selector valve assembly of claim 17 wherein said pressure operative motor is a pressure operative diaphragm disposed gas-tight against the upper end of said housing member outside said tank, a bonnet disposed on the side of said diaphragm opposite said housing member and an excess flow valve in said bonnet to regulate gas pressure in the space bounded by said diaphragm and said bonnet.

19. In the liquid-vapor selector valve assembly of claim 17 wherein said pressure operative motor is a pressure operative bellows.

20. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, in combination, a housing member, said housing member being adapted for installation in the upper portion of a liquefied petroleum gas storage tank, a plate in the lower portion of said housing member, an opening in said plate, a liquid dip-tube disposed in said opening and providing communication from the liquid containing space in said tank to a space above said plate, a resilient sealing member supported by the top surface of said plate, a piston in said housing member adapted for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit through the vertical length of said piston, said tubular piston rod extending downward through said bellows to a level adjacent said resilient sealing member, the lower end of said tubular piston rod being adapted to seat against said resilient sealing member at the lower end of the stroke of said piston, said tubular piston rod and said conduit extending through said piston providing communication from a space below said pressure operative bellows to a space above said piston, a port in the wall of said housing member at a point above said piston when at the bottom end of its stroke, an excess fiow valve in the upper end of said housing member, and means for attaching the outer end of said excess flow valve to a conduit for passage of fuel to a point of use.

21. A liquid-vapor selector valve assembly for use in liquefied petroleum gas fuel systems comprising, in combination, a housing member, said housing member being adapted for installation in the upper portion of a liquefied petroleum gas storage tank, a plate disposed vapor-tight in the lower portion of said housing member, an opening in said plate, a liquid dip-tube disposed in said opening 11 in said plate and providing communication from the liquid containing space in said tank to a space above said plate, a resilient sealing member attached to the top surface of said plate, a piston in said housing member adapted 'for reciprocating movement therein, a pressure operative bellows attached to the lower portion of said housing, said pressure operative bellows being responsive to externally applied pressure, a tubular piston rod connecting said bellows and said piston, a conduit through out the length of said piston, said tubular piston rod being connected with said piston in such a manner that the conduit of the tubular piston rod communicates with said conduit in said piston, said tubular piston rod extending through said bellows to a level adjacent said resilient sealing member, the lower end of said tubular piston rod 12 being adapted to seat against said resilient sealing memher at the lower end of the stroke of said piston, a port in the wall of said housing member at a point above said piston when at the bottom end of its stroke, and means for attaching the outer end of said assembly to a conduit for passage of fuel to a point of use.

References Cited in the file of this patent UNlTED STATES PATENTS 1, 50,893 Morrow Apr. 3, 1923 1,940,090 Hetherington Dec. 19, 1933 1,962,214 Russell et a1. June 12, 1934 2,226,810 Ensign et al. Dec. 31, 1940 2,365,423 MacSparron Dec. 19, 1944 2,543,920 MeCabe, Jr. Mar. 6, 1951