US2400570A - Liquefied petroleum gas dispensing system - Google Patents

Description

May 21, 1946. H, L, NORWAY 2,400,570

LIQUEFIED PETROLEUM GAS DISPENSING SYSTEM Filed Dec. 19,1940 3 Sheet s-Shet 1 HIS ATTORNEY May 21, 1946.

H. L. NOR WAY LIQUEFIED PETROLEUM GAS DISPENSING SYSTEM Filed Dec. 19, 1940 v FIGS 3 Sheets-Sheet 2 OLDi. NORW HIS ATTORNEY May 21, 1946. H. L. NORWAY ,400,

LIQUEFIED PETROLEUM GAS DISPENSING SYSTEM Filed Dec. 19, 1940 5 Sheets- Sheet s rm sm'zi, 194s UNITED" STATES time PATENT oriici- HQ UEIEDPETIOMGASDISPENSING T v HaraldLNcrwamEn-nstommassignorto'lhe Bastian 1 a m s-corpora Application Dceemher is, 1m Serial No. swam z: chime (c1. ez-ii 'withthe assistance or the heat'oi the earth and reductioninpressure isvaporized i'oruse in a dwellingas asuhstitute tor-natural gas. I

One way of vaporizing the liquefied gas isthe so-rcalled batchsystem in which the vaporization is carried on in the'storage tankand vapor is withdrawn in the form 01' gas from the tank.

' The otherway-ot vaporizing the liquefied gas is these-called "fiash system in which the liquefiedgasiswithdrawnasaliquidiromthetank and-passed through a presure reducing'regulator which causes the liquid to ilash into vapor. Wherever the vaporization takes place. heat unitsare absorbed from surrounding parts. and.

in the batch system; this refrigerating action is largely expended in the tank, whereas, with the fiash system, the heat absorption is concentrated in a comparatively small space, namely, around the pressure reducing device and adjacent parts. 5

Although the present invention will improve vaporization and operating conditions .ior both systems, itis primarily of interest with the flash systems and has for one oi its objects the adapta tion of the hash process to. take advantageoi thebenefits derived with batchsystems in-thatthe latent heat required .i'or vaporization is taken iromthelargebodyotliquidinthetankasin thecaseoihatchvaporization. Y

a iurtherobject oi the invention a to prevent ircstingotthe bcdyoitheregulatorin'which the dash vaporization takm place. In thisccnnection,anotherobjectottheinventionistosubmerse in an anti-ireese solution, thoseparts of the resulator which are subject to. the refrigerab ing eil'ect oi the vap ti ase pressure reduction. I 1 Another object or the'invention is to circulate asourceotheatsuchsstheearthoveranarea D greatly in excess'oi' the area of the regulator.

Another object oi the invention is to provide an improved means for determining the level of liquid in the tank and for evacuating from the tank such foreign fiuids as water.

A further object of theinvention is to provide an improved means tor preventing the filling oi the tank above a predetermined level.

A further object oi the invention is to provide an improved shutoii' control 'ior thesassu ply leading item the tank which is not exposed to' atmospheric temperatures.

Another purpose oi the invention is to provide a dispensing system of the class described where,

under" normally expected conditions of heavy withdrawal, a revaporlzer is not needed, yet 'without changing the general organization of standardised partsvalrevaporiser may be used where extra heavy withdrawals 0! gas are anticipated and 'condensati'on is likely to beincurred.

A further purpose oi the invention is-to provide a rugged. unitary tank assembly which is simple in construction, easy to make, readily placed in operation and serviced.

These being among the objects of the invention,

other and further objects will become apparmt' from the drawings. the description relating thereto and the appended claims.

l'teierringnowtothedrawingsi- Hg. 1 is a fragmentary vertical section taken longitudinally thro a'h the tank, standpipe and eduction cavity illustrating one of the improved embodiments of the invention.

sure reduction regulator in section.

4 is ew similar-to 1 illustrating another improved embodiment oi the invention.

5 shown in Fig. 4.

transverse section taken"- .llpolltheiineI-Iihl'lg.1, s.ls' shiiwin ;thepresis an end view of theeductionfcavityan anti-freeze liquid ccnvectively. in heat 'exm, i .Wcontactwiththefirstst seregulatorand mm, asourceotheat,inthis instancethescurceof/ Plm'l'is heat preferably being the heat oi the earth. so .otanimproved icrin'oi a means-for preventing ..Ai rth rw p0eeottheinventionistovent to the same mti-ireese liquid which .e nveysheattotheregulator. I

Amtherobiectoitheinventionisw-a withtheltandpipe. H v fiashmulatorinccntactwitheliquid to ligJ-isasectioushowinganimprovedexcess an eievational view, partly in the oi-a tank above a predetermined, level. Pig. 8 is an eniargcd-vertical'secflon showing the relative locations eitheelements associated w standpipe.

flow check valve mounted from inside the eduction cavity. I

Fig. is a perspective view of the top of the As already mentioned, the invention is illustrated in connection with a flash system of varegulator which reduces the pressure whereby the liquefied gas is vaporized and the resulting vapor is then conducted through and to a second regulator where it is reduced to a service pressure of 6 ounces per square inch. In the drawings, 1s-

a storage tank is indicated at II as buried in the earth 12, below the frost line 53 nor-man expected to exist in the region where the installation is made.

Tank construction It apertured on the top at IE to receive the standpipe 22 which is welded therein as by a weld line ll. On its bottom. the shell 14 is provided'with an opening [8 that partially overporization where a liquefied gas is forced from a a storage tank by the vapor pressure of the stored gas :and is passed through a first stage- 52 is provided with a back pressure check valve which is opened by vthe pressure forcing liquid into the tank and the bottom 54 thereof is threaded at 55, as more particularly shown in Fig. 7, to receive a fitting 56having a discharge opening El from the side thereof and a lisp shutofi valve 58 pivoted'as at El on the bottom and outside thereof where it is easily assembled.

The flap valve 58 is held normally opened by a weight 62 upon the other end of a curved arm 53 which extends through the opening 51 to con- $.20 The tank comprises a cylindrical central shell laps a vertical projection of the opening it, and

the opening I8 is closed by a cup 2| welded thereto asst-22 to provide a sump 23. A support 24 inside of the shell M as at 26 and forpurposes of installing the tank properly in place so that the sump 23 works most effectively, the standpipe IBp is *so positioned as to provide an angle at 21 which is slightly in excess of a right" angle.

When the tank is buried, the plumbing of the standpipe IE will assure thatv any water collecting in the tank will lie to the right of the sump 23-until such time as the amount of water by caps 3| and 32 secured by welds, 33; The cap' for the 'revaporization coil 25 is welded upon the is apertured as at 34 to receive the well member 35 welded therein as at 38 to provide a cavity 31 in the" tank, and the tank is preferably constructed and assembled in this order.

.S'tcndpipe construction The standpipe '86 comprises a cylindrical casing 38 closed at the top by a wall 4! spaced from the top 42a suilicientdistance to provide arecess 48 therein.

Referring to Figs. 3, 8 and 10, a slip tube gauge 44 is threaded into an opening 45 in the wall 4| where the lower end 48 or the gauge thereof enters. the-sump 23. vided with a stop 41 which prevents complete removal or the slip tube gauge and in addition to the slip tube gauge functioning in the conventional manner to determine the level of the liquid in the tank, the stop 41 has an opening 5| therein withthe mouth of the opening close to the bottom of thesump 23 so that water present in the sump will be evacuated through the slip tubegauge whenever the slip tube gauge is all the wayvdown and the. top is vented in the same mannerin which the slip tube is employed as a auge. The slip tube gauge would be left open as long asv it was discharging water and could trol the movement of the valve 58. A recess 64 protected by a shielding lip receives the flap valve 58 in one sideof the fitting 55 where it is protected against a closing action of the flow of liquid passing down the pipe, through the opening51. The valve 58 and the weight 62 are so balanced as supported by the pivot Bl that an appreciable upward pressure upon the'wei'ght 62 will cause the flap valve 58 to leave the recess 64 and enter the path of the incoming fluid.

The flowing fluid then causes the valve to close and when closed the valve positively stops the how of liquid into the tank in a manner preventing the filling of the tank above a predetermined level. A valve'actuating means that is responsive to the level of the liquid in the tank,= such as a float 66 is employed to actuate the valve and supply the required upward pressure at the proper time in the filling operation.

In order to actuate the valve 58: the float 66 is mounted upon an arm 51 which is pivotly mounted upon the same axis 61 as the valve and in the preferred embodiment of the invention the float arm Bl engages a stop 68 upon the weight 62 as the liquid and float 56 approach the predetermined safe filling level.

Although in less expensive installations, the float 66 might serve as aweight, it is preferred that the weight 62 be provided and be movable separately from the float away-from the armt'l as the flap valve 58 is closed. In this way there is no straining of parts when the valve 58 is closed quickly by the incoming liquid and once the liquid supply line is turned off at the service tank, a,

vent-hole H will permit the liquid to drain.

The lower end 46 is probe cases] again whenever liquefied .gas began to now.

through the flap valve and permit the weight 82 to reopen the valve 58. f1 a It is preferred that the opening 51 be directed towards the left end of the tank as shown in Fig. 1 whereby the eddy current developed by the incoming liquid will tend to keep any water condensation in the-tank away from the liquid eduction tube Ill. I

In this way a positive shutoff is provided to prevent anoverfllling of the tank, thereby avoiding the deficiencies of conventional practice in which vapor return gaugesare ,inadequate'due to the peculiar nature of the liquefied petroleum gas.

vWith certain conventional devices the continuance of filling pressures in the tank cause a liqueflcation of the gases already there and the level continues to rise regardless of a dip .tube

H which is opened when the nozzle of th vapor return hose is connected thereto. 7

a vapor return connection is not en- II are mounted upon the wall .is threaded into the valve,

7 fled gas from the tank into the Apressure-gaugeII and a satety' relief valve I andaisoashait II whichcanbemanually turnedbythewinged handle II to control thepassage of liquid through the eduction pipe II more specifically described hereinafter. 1

The lower end of the shaft II is provided with a wrench socket 18 having a flared mouth II which serves as a guide to en age with the valve shalt 02 which controls the operation of the eduction tube 10. v a i When the tank is buried in the ground, the upper part of the standpipe II is located in a concrete box or vault II having a cover plate 8| secured thereto by bolts III. The cover It seals the space II and a vent I1 is provided for-free venting of the vault to atmosphere in the event the-safety relief valve is called upon to function. In order to prevent water from collecting in the recess II at the top of the standpipe the wall; 01' 204 the standpipe are drilled as at II Just above the wall II to drain water collecting in the recess II.

Eduction eaoityGcneral construction Referring now to the eduction cavity II the well member II is a fabricated construction com- 7 v prising a cylindrical tank or shell II which is about 6" to 8" in diameter and the same in length. The shell II is closed at its inner end bya v plate 92 welded marginally thereto and the outer end ha a wall II which is 2" or 3" high. The opening above the wall II is sealed by a head It and gasket 96 held in place by bolts II.

A. Eduction cavity shown in Figure #1 Referring to Figs. 1 and 2, the plate I2 is peror prasures between the atmosphereand the eductioncavity II. The headllisalsoprovided with a liquid'level drain or opening III which prevents the cavity "from being filled with liquid above a l determined point.

. Thecavity Ilisiilledprel'erablybyananth out through the opening III. Otherwise the vent opening? I2 i i provided with a tube III to trap air above the liquid level and prevent a flooding oi the cavity II in event an excessive amount of water is present at any one time B. Eduction cavity shown in Fig. 4

To theextent that the parts are alike in the.

two modifications. identical numbers have been used. and to the extent that'the parts are substantially identical, the siimx"'A is used. In Fig. 4 the embodiment is shown by which the liquid stored in the tank is employed a; the

anti-freeze solution in the cavity 31. Although the coil It may be employed or not employed in either or both of the embodiments illustrated, depending upon extreme gas withdrawal conditions expected to be experienced in any particular installation, the embodiment shown in' Fig. 4 is illustrated without the coil. In Fig. 4 the plate a i one without any .openings therein so that pressures inside the forated to receive the two ends'oi. a revaporation coil 23 at preferably vertical spaced points in which the outlet end 97 or the coil is low enough to pass through the wall II. In this construction when the coil is welded in place as by welds II the coil is rigidly supported and held in place at three spaced points.

valve fitting III Referring to Fig. 8 a shutofl plate I2 through the opening I02 and comprises a main a valve compartment I lied gas is conducted by II through an inlet therein to which liquethe liquid eductlon pipe p ss geway Ill and from which an outlet passage III leads from the valve opening In! controlled by a valve member III.

It is preferred that the valve liquid, "so that the valve compartment I It can be located upon the pressureside oi the valve. Then there is no need for packing where the valve stem I! is threaded through the valve cap I II as at -I I2.

'I'huis, as already mentioned. the flow of liqueeduction cavity is controlled by the handle "II standpipe II. g

The outlet passage I II .01 the valve body III is connected to a first stage regulator-III by means of couplings land a short elbow III, one of the couplings comprising a union so that the regulator may be removed and attached at will The out-.

bodyportion III having be a negative type i. e. one','opening against the flow oi the at the top of the let side III oi the regulator is connected to the mountable and removable from 85 or the parts is threaded into the welded boss II! tank II and inside the cavity I! may be equalized without any leakage through the head 94a. Equalization is bad by mean -oi anmanual shutol! valve III threaded into the bottom wall of the cavity as at III. The valve III is controlled by a shaft III extended through the wall Ila andsealed by a suitable packing (not shown) and when opened said valve permits free flow oi liquid between the tank II and the vcavity II.

In order to provide for convective circulation of liquid through the cavity 31 an excess flow check valve III as more particularly shown in Fig. 9 is threaded into the boss III to seal the cavity I'I'irom the tank when there is. anexflow from the tank into the cavity 31.

The excess flow valve III is of the slug type the inside of the cavity "either as a complete unit or part by part. The valve casing III which carries the rest as at I I1 and when withdrawn, serves to remove the valve as a unit. The valve casing III receives a threaded plug III therein which i provided with a valve seat III and a shoulder III which co-operates with the slug check I and a spring I by which the slug check I 43 is normally urged away from the seat ill. In event it is desirable to remove only the valve parts, the plug III may be loosened while the casing III is held tightly in' place thereby permitting repair and replacement oi the valve in whole or In the event it becomes desirable to service the regulator III in. Fig. 4, the valve III is closed and the bolt; It loosened. This will permit the sudden escape or pressure from the cavity 3! and the excea flow check valve will'close automatieally, The cavity II will evacuate llithereintomaintainan qualisation itself and the head 94a may be completely withdrawn to service the regulator.

First stage regulator atcasro in which the regulator is disposed, to supply that heat to the liquefied gas as it is vaporized; V

In the'construction shown, the inlet passageway I" leads to a downwardly opening valve port I48 which is closed by a vertically movable centerpiece II carrying a seat I52 and a seat, retainer I63. v v

The centerpiece is forced upwardly by a back cap spring I54 held in place by a backcap I55 threaded into the body I45 as at I56. A yoke I51 spans the port I48 to support the seat. At

its top, the yoke I51 is threaded to receive the diaphragm IEI which is held in place-by a threaded diaphragm plate I62. Marginally. the diaphragm IGI seals the expansion compartment I63 and is held in place by a bonnet I which carries an adjusting screw I65. The adjusting screw serves to regulate the pressure exerted by a, spring I66 supported thereby so that the spring I66 opposes the action of the back cap spring I54 to hold the seat I52 away from the port I48 thereby permitting free flow of liquefied gas through the port I" until the pres-- sure differential is built up against the lower face of the diaphragm s'umcient to close the valve I52.

The space in the bonnet above the diaphragm is vented to atmospheric pressure through a vent pipe I61 securedthereto by a union I68 having a fiare nut III.

In the particularembodiment shown in Fig. l

v the tubeI-GI opens into the interior of the cavity 31 and into the anti-freeze liquid I20 to prevent water condensation therein, while in the embodi- .-ment illustrated in Fig. 4 the tube IIi'Ia opens outside of the cavity through the wall 93a. In

this last instance, there is little danger of a freezing of any moisture that might get into the tube IIi'la, because it is completely submerged in the eartahI warmed liquid circulating through the cavity l v Second stage reduction I The outlet of the regulator II3'is connected to the second stage regulatorby a service conduit IBI which may be made of any suitable length to locate the. regulator II8 inside or outside the dwelling or in the basement or upon the first floor of a dwelling wherever it is found desirable to locate the regulator.

The regulator II8 receives the gas under'5# to 20# pressure from the first stage regulator I II,

and reduces it to a working pressure of ll" of water column, the pressure conventionally used with gas burning appliances.

Assembly In assembling the eduction cavity all the parts are assembled thereto and the unit is then in.- serted into the opening 34 and welded in place by'the weld line 38 after which the valve control shaft I5 is inserted and lowered to engage the socket 18 over the handle 82 as guided bythe' fiared mouth 8|. The mechanic can see to .do this-by looking through the relatively large opening 53. Thereafter the fill pipe 82 is mounted in the opening 53, the slip tube gauge is inserted v and'the fittings mounted upon the plate A I. The tank is, then ready for shipment rand in its as- The cover 84 for. the

Installation As already mentionedthe tank is buried below the frost line. Before the earth is filled into the trench around the tank the cavity 31 is attended to. In event theembodiment shown in Fig. l

is employed the fill plug at I2I is removed and the cavity 31 filled'with the non-miscible liquid to a level at which it begins to run out of the drain vent I22.

In event the embodiment is installed which is illustrated in Fig. 4,.the' shaft in is turned to open the valve I3I before the earth is filled in the trench.

After the tank is covered with earth, the standpipe It being free'of side obstructions, the concrete box 83 may be received and lowered in place with a snug fit around the standpipe. Thereafter the filling of the trench in which the tank is placed is completed. v

box It may be removed at any time during the operation and the fill pipe connected with the source of liquefied petroleum gas under pressure. In event a vapor return connection i provided. this also is connected with a supply tank to equalize the pressures between the supply tank and the-storage tank. The weight of the fioat 66 or weight .6! will maintain the check valve open to permit the liquefied gas to enterthe tank, the level of which gradually rises until it comes in contact with the float 86.

Thereafter the 'fioat moves from a position inclined to the vertical to a positioned inclined to the horizontal and thereby increases its effective leverage during the lostmotion between the float arm and the valve arm. Thereafter the float moves the valve outwardly gradually into the The heat absorbed from the liquid body is replaced convectively through the walls of the cavity 81 (Fig. l) or by convective circulation of the liquid in the tank through the openings in the wall 31. As heat is absorbedin this relationship the body of liquid in the tank replaces it with heat absorbed from the earth.

Thus, it will be seen with the present construction that heat units are supplied directly in a new and improved manner to that part of the system, namely, the first stage regulator. where the greatest refrigerating eflect is experienced.

Consequently, although several preferred embodiments of the'invention have been discussed and described herein, it will be apparent to those skilled in the art that various changes, modifications and alterations maybe made without departing from the. spirit or the invention, the scope of which is commensurate with the claims.

What isclaimed is: Y

i. In a liquefied petroleum vgas system, a tank comprising a cylindrical central shell having an aperture and a side opening therein, a standpipe secured in said aperture, a cup covering the openmg and providing a water sump, end members for the shell, one of said members having an o ing therein, a well in said opening, an .eduction member mounted upon the standpipe and terminating in said cup, a liquid eduction tube mounted upon the well,-a pressure reducing regulator connected to said eduction tube, a closure for the well, anti-freeze means in said well in contact with said regulator, a valve between the eduction tube and regulator and means mounted upon the standpipe for operating said valve.

2. In a liquefied petroleum gas system, a tank' construction comprising a shell including means for filling the tank, a cavity in one end of the tank, a closure for the cavity, a pressure regulator disposed in the cavity, a gas eduction conduit comprising one section leading from the interior of' the tank to the regulator and a service line leading from the regulator to apiece of consumption,

and liquid means in the cavity in contact with the regulator body and the wall of the cavity.

4. A liquefied gas dispensing system comprising a tank, a standpipe, means carried thereby for filling the tank, a'pressure reduction regulator having a bonnet and located below the level of the filling limit of the tank and in heat exchange contact with the convec'tively circulating contents of the tank, and a vent for venting the bonnet of the regulator to pressures lower than tank pressure. 5. A liquefied gas dispensing system comprising a tank buried in the ground and having a body of liquid therein absorbing heat from the surrounding earth, a gas conduit including a pressure reducing regulator in heat exchange contact with said body of liquid, means ahead of the pressure regulator for controlling the flow of gas through,

the conduit, and means accessible from above the ground to control said last means. i 6. A liquefied petroleum gas dispensing system comprising a tank buried in the ground below the frost level, a pressure reducing regulator disposed below the fill limit of the tank, and a'bcdy of liquid supplied with heat from the tank in convectively circulating contact with the regulator. 7. A liquefied petroleum gas dispensing system comprising a tank buried in the ground and having a liquid therein absorbing heat from the surrounding earth, and a pressure reducing regulator gisposed in said liquid and receiving heat theremm' 3. A liquefied petroleum gas dispensing flash system comprising a tank buried in the ground and having a body of liquid therein supplied with heat from the ground, a first stage pressure redisposed in contact with said ducing regulator body oiliquid andrecelving heat therefrom, and means connecting the regulator with a source of liquefied gas under pressure, and a service line trolled b said diaphragm, an outlet from the housing upon said other side, and means for con-' ducting liquid to the valve from said liquid eduction conduit. 1

10. The process of vaporizing a liquefied petroleum gas'comprlsing dividing a body of liquefied petroleum gas'in several parts, passing one part through a'metal body in heat exchange rela tionship with the other part confined to circulate convectively and reducing to a predetermined pressure the pressure of said one part while in contact with the body, withdrawing from the body' the pressure reduced part to a point of use and continuously supplying heat to said other part from a source including the earth.

- 11."Ihe process of vaporizing a liquefied pe-f troleum gas-below the frost line in the ground comprising passing the liquefied gas through a metal body, supplying the body with heat from a liquid circulating in direct contact with the body and simultaneously reducing the pressure of'the liquefied gas in the body to a regulated pressure and supplying the liquefied gas with large quantiv ties of heat from the'body.

12. A liquefied gas dispensing system comprising a tank buried underground to receive heat therefrom below the i'rostline, means for filling the tank from above ground, a cavity in the wall I of the tank, a regulator mounted in the cavity, a

closure for the cavity, means for educting the contents of the tank to a point oi use through the regulator, and means for conveying heat from the contents of the tank to the regulator comprising an element in heat exchange relationship with the regulator.

'13. The process of dispensing liquefied petroleum gas in its vapor phase at its point or use comprislng bringing a flowing stream of liquefied petroleum gas into heat exchange relationship with a body of liquid, disposed in heat exchange rela-.

tlonship with the earth below the frost line, re-' ducing thepressure upon said flowing stream to a regulated pressure below the vapor pressure of said flowing stream while said flowing stream is in heat exchange relationship with said body of liquid to vaporize said flowing stream, and conducting the vaporized gas to the place of use. 14. A liquefied petroleum gas vaporizing apparatus including, a tank adapted to beburled underground to receive earth heat, conduit means in the tank having an inlet and an outlet and including a pressure regulating valve connected leading from said regulator toa place of co'nthe other side of which is exposed to discharge pressure; a valve upon said other side and con in the conduit means between the inlet and outlot 01' the conduit means, part of the conduit means constituting means for connecting. the pressure'regulating valve with a source of liquid petroleum gas, and a body of heat transfer liquid in the tank surrounding the regulating valve and said conduit means to conduct earth heat from the tank to the regulating valve and said conduit means. v

15. A liquefied petroleum gas vaporizing apparatus including, a tank adapted to be buried underground to receive earth heat, an expansion and gas storage element ha i g a portion disposed in the tank, a pressure regulating valve in the tank and connected with the expansion and gas storage element, a liquefied petroleum gas supply pipe for connecting the pressure regulating valve with v a liquefied petroleum gas supply, a body of heattransfer liquid in the tank surrounding the regulating valve and said portion of the expansion and a as storage element to conduct earth heat from the tank to the reslflatlns valve and said portion of the expansion and gas storage element, a discharge pipe connectedlwith the expansion andgas storage element, and a low pressure regulating valve interposed between the storage element and said discharge pipe. i

16. A liquefied petroleum gas vaporizing apparatus including, a tank adapted to be buried underground to receive earth heat and having a body of heat transfer liquid therein, an expansion and vaporizing coil having a low portion thereof in the tank in heat exchange relationship with the liquid therein, a pressure reducing valve within the confines of the tank in position to receive heat from said liquid, said valve being connected with the expansion and vaporizing coil, means for conducting liquefied petroleum gas to the valve under pressure, a service conduit means connected to the expansion and vaporizing coil, and a low pressure regulating valve in said conduit means.

1'7. A storage tank for liquefied petroleum gas,

a liquid eduction tube and regulator mounted within the contour oi the tank, and means for sealing off the regulator from the pressure existing in the interior or the tank at will whenever it is desirable to service the regulator including a housing for the regulator, and a removable wall secured to the tank for providing access to the regulator.

18. In a liquefied'petroleum gas dispensing system, a pressure reducer'for flash vaporizing liquefied petroleum gas comprising a body defining a valve compartment, said body having a passageway therethrough terminating in a valve port opening into the compartment, a valve member cooperating with said port, means responsive to the pressure in the compartment for controlling the action of the valve, and means upon the body for absorbing heat from the environment of the body to supply the latent heat of vaporization to the liquefied petroleum gas present in said compartment in its liquid phase.

19. A liquefied petroleum gas vaporizing apparatus including a tank adapted to be buried unmodem inlet of the expansion and gas storage element, means connecting the pressure regulating valve 'with a source or liquefied petroleum gas, and a body of heat transfer liquid in the tank surrounding the regulating valve and said portion of said expansion and gas storage element to conduct earth heat from the tank to the regulating valve and said portion.

20. The process 01 vaporizing a liquefied petroleum gas comprising passing liquefied gas in its liquid phase into a metal body, supplying the body with heat irom'a convectively circulating body of liquid outside of the metal body, simultaneously reducing the pressure of the liquefied gas present in the metal body to a predetermined pressure, and supplying-said body of liquid with heat from the ground.

21. In a, liquefied petroleum gas dispensing sys-' tem the combination of a tank constructed to be buried in the ground below'the frost line, an expansion regulator for vaporizing liquefied petroleum gas disposed below the fill limit of the tank in position to be supplied with latent heat of vaporization from the contents of the tank by convective circulation of liquid in the tank when liquid is present in the tank.

22. A liquefied petroleum gas dispensing system comprising a tank constructed to be charged present in a metal derground to receive earth heat, an expansion and gas storage element having an inlet and an outlet and a portion thereof disposed in the tank,

} earth.

with a body of liquid and to confine the liquid to convective circulatio a pressure reducing expan.

sion valve forvaporizing liquefied gas disposed to be bathed with liquid in the tank in heat exchange relationship therewith when the tank is charged with liquid whereby latent heat of vaporization required to vaporize liquefied gas handled by the valve is supplied from said body of liquid.

23. The process of substantially completely vaporizing a liquefied petroleum gas comprising siinultaneou'sly reducing to a predetermined pressure the pressure upon the liquefied petroleum gas warm body of liquid circulating .in direct contact with the body and in heat exchange with the morn L. NORWAY.

body in its liquid phase and supplying the metal body with heat units froma

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