US2449351A - Method of and apparatus for dispensing liquefied petroleum gas - Google Patents

Description

IETHOD OF AND APPARATUS FOR DISPENSING LIQUEFIED PETROLEUH GAS Filed Fab. 8. 1945' INVENTOR.

L. JWbit'e,

ATTGRNEY Patented Sept. 14, 1948 METHOD OF AND APPARATUS FOR DIS- PENSING LIQUEFIED PETROLEUM GAS Loyd J. White, San Antonio, Tex., assignor to Southern Steel Company, San Antonio, Tex.,

a corporation 01' Texas Application February a, 1945, Serial No. 576,735

9 Claims. 1

This invention relates to a method of and apparatus for dispensing liquefied petroleum gases, such as mixtures of commercial butane and propane. and, among other objects, aimsto provide an eificient method of vaporizing the fuel mixture in separate stages.

Another aim is to provide an improved underground liquid eduction system of the two-stage pressure reduction type having provision for separating flashed vapor from the residual liquid after the liquid passes through a first-stage regulator and for vaporizing such residual liquid by absorption of heat from an underground vaporizer.

Another aim is to provide, in a system of this general type, a novel separator arranged to separate flashed vapor from residual liquid, an underground vaporizer for the residual lquid and a superheater for the vaporized residual liquid connected in series with the vaporizer and arranged withln' the pressure storage container to absorb heat therefrom.

A further aim is to provide important improvements in the general type of underground system disclosed in my Patent No. 2,260,356, dated October 28, 1941.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawing, wherein:

The figure is a transverse sectional view of an underground system embodying the invention.

Referring more particularly to the drawing, the illustrated embodiment of the invention, there shown, is designed to increase the vaporizing capacity of a two-stage pressure reduction system of the general type disclosed in the aforesaid Patent No. 2,260,356 and to insure the delivery of gas of a uniform B. t. u. content from a. mixture of liquefied petroleum gases, such as commercial butane and propane. It is also designed to supplant systems of the type shown in my copending application Ser. No. 237,113, filed October 26, 1938,

wherein educted fuel is completely vaporized between two pressure reducing regulators and the vaporizing heat has to be supplied by the fuel contents of the pressure storage container. Experience has demonstrated that mixed, flashed vapor and residual liquid'from a first stage. pressure reducer or regulator cannot absorb sufiici-ent heat from the fuel contents of a storage tank to insure complete vaporization of the liquid under maximum fuel load conditions, especially when the storage tank is nearly empty. Furthermore, it has been found that the capacity of a. vaporiger is greatly reduced when a mixture of flashed vaper and the liquid are passed through a heat exchanger, because the volume of the slugs of vapor is much greater than the volume of the residual liquid. 1

It is, therefore, an important aim of the present invention to overcome the foregoing disadvantages by providing mean for separating flashed vapor from residual liquid passing through a first stage pressure reducer and then vaporizing theresidual liquid in a heat exchanger which is separated from the fuel storage container. Moreover, the present improvements provide for superheating the vapor of the residual liquid by absorption of additional heat which may be derived from the fuel contents of the storage container.

In the present example, an underground pressure storage tank I is shown as having a standpipe ll connected thereto and carrying a valved filling and dispensing fitting 12 preferably of the general type shown in my Patent No. 2,176,829

. (Figs. 2 and 3). A liquid eduction pipe 13 extends i sure reducing regulator I6.

downwardly from the fitting to the bottom portion of the storage container andthe fitting is shown as carrying an ordinary liquid level gauge in the form of a slip tube I4. Such fittings are now well known in the art and requireno further description.

Liquid is discharged, as needed. from the bottom of the tank through the eduction pipe, thence through a valved outlet 15 and a first stage pres- The educted liquid is partially flashed into vapor as it passes through the first stag-e regulator and the mixed, flashed vapor and the residual liquid are conducted through a conduit I! to a vertical vapor separating chamber l8 conveniently supported by the standpipe. This separator is preferably in the form of a large section of pipe closed at both ends and having a vapor discharge tube 19 extending through the bottom to a point near the upper end. The arrangement is such that the flashed vapor rises in, the separating chamber l8 and passes out through the spur tube 19. The residual liquid falls to theebottom of the chamber and is conducted therefrom through a tube 20 to be vaporized. t

In this instance, the tube 20 is shown as conducting the residual liquid to an underground heat exchanger which includes a buried contain-er 2| filled with a trapped liquid heating medium, such as water with some alcohol or other miscible antifreeze substance to lower its freezing point. The container i shown as being cylindrical with rounded or hemispherical heads and it has heat vto absorb re vaporizing heat therefrom.

conducting fins 22 to increase its heat absorbing capacity. The container is adapted to be filled through an upstanding pipe 23 accessible from above the ground. The pipe 20 is connected to a heat exchanging coil 24 within the tank and the coil has a vapor outlet pipe 25. The container 2| has a hand hole opening at one side of its upper end to receive the coil 2| and the arrangement is such that the coil absorbs heat from the liquid and sets up rapid thermosyphonic circulation thereof in the container. The shape of the container is suchas to facilitate this circulation.

- The vapor of the residual liquid is shown as being conducted through the pipe 25 back to a point above the storage container or tank I0, thence through a superheating coil 26 extending down-- wardly into the bottom portion of the tank to absorb additional heat from the liquid fuel in the container. The coil 26 has a vertical outlet pipe 21 extending through the wall of the container and connected to a T fitting 28 which is also connected to receive the flashed vapor from the spur tube I9. The flashed vapor and the superheated vapor are here combined and are conducted through a pipe 29 to a second stage pressure reducing regulator 30 which reduces the pressure to about six ounces and delivers the gas to a service pipe 3i leading to the usual gas consuming appliances. In this example, the service pipe has its lowest point at a T fitting 32' above the storage container I and a re-vaporizing pipe 33 for any condensed liquid in the service'line extends into the storage container course, it is contemplated that an underground re-vaporizer of the type shown in my Patent No. 2,105,383 may be employed.

It will be noted that all of the controls and external appurtenances of the system except the external -vaporizer are housed within a sing-1e protecting casing 34 of the usual type employed in underground systems (as shown, for example, in my Reissue Patent No. 21,470).

From the, foregoing description, it will be seen that the improved two-stage system has greatly increased vaporizing capacity. It is contrived to insure continuous delivery of gas to meet the maximum gas demand. The heat exchangers, connected in series, provide for superheating the vapor of the residual liquid and prevent condensation of the mixed vapors before they reach thesecond stage pressure reducing regulator.

Obviously, the invention is not restricted to the particular embodiment thereof herein shown and described, but is capable of various changes within the scope of the appended claims.

What is claimed is:

1. That method of generating and dispensing gas which is characterized by storing a quantity of liquefied petroleum gas under its own vapor pressure; discharging liquid as, needed by virtue of such pressure; subjecting the discharged liquid to a first stage pressure reduction, thereby causing a portion thereof to flash into vapor; conducting the flashed vapor away from the residual liquid; conducting the residual liquid to a separate vaporizer and independently vaporizing it; and then combining the flashed vapor and'the vapor of theresidual liquid and subjecting them to a second stage pressure reduction ready for use in gas consuming appliances. 4

2. The method, as set forth in claim 1, further characterized by superheating the vapor of the residual liquid before it combines with the flashed vapor.

3. The method, as set forth in claim 1, further characterized by subjecting the vapor oi the residual liquid to heat exchanged with thefstored liquid fuel to superheat the vapor before it'combines with the flashed vapor.

4. The method as set forth in claim 1, wherein theresidual liquid is vaporized by absorption of heat from a segregated body of liquid heating medium buried in the ground and deriving its heat from the surrounding earth.

5. That method of generating and dispensing gas from a mixture comprising butane and propane, which is characterized by storing a quantity of the liquefied fuel under its own vapor,

pressure in an underground container; discharging the liquid fuel. as needed, due to its.

'in the container to absorb more heat therefrom;

and then combining the flashed vapor and the heated vapor of the residual liquid and sub-' jecting them to a second stage pressure reduction ready for use in gas consuming appliances.

6. In a, liquefied petroleum gas storage and dispensing system of the class described. a pressure storage container adapted to be charged with the liquefied gas; a liquid eduction pipe communicating with the bottom portion of the container; a first stage pressure reducing regulator connected to the liquid eduction pipe; a vertical separating chamber communicating with the outlet of said regulator having means to separate the vapor formed from the residual liquid a vaporizer connected to the bottom of said chamber to receive and vaporize the residual liquid; a heat exchanger connected in series with said vaporizer to superheat the vapor of the residual liquid; and a second stage pressure reducing regulator communicating with the vapor space of the separating chamber and with said heat exchanger to deliver the combined vapors at service pressure for use in gas consuming appliances.

'7. In a. liquefied petroleum gas storage and dispensing system of the class described, an underground pressure storage container adapted to be charged with the Iiquefledgas; a liquid eduction pipe communicating with the bottom portion of the container; a first stage pressure reducing regulator connected to the liquid eduction pipe; 3, separating chamber communicating with the outlet of said regulator having means to separate the vapor delivered from the regulator from the residual liquid; an underground vaporizer separated from the storage container and connected to said chamber to receive and vaporize the re- Sidual liquid; a superheater for the vaporized residual liquid connected in series withsaid vaporizer and located within the container to absorb heat from the liquid fuel therein; and a second stage pressure reducing regulator communicating ground pressure storage container adapted to be charged with the liquefied gas; a liquid eduction pipe communicating with the bottom portion of the container; a first stage pressure reducing with said vaporizer to deliver the combined vapors at service pressure for use in gas consuming appliances, i

9. In a. liquefied petroleum gas storage and dispensing system of the class described, an underground pressure storage container adapted to be charged with the liquefied gas; a liquid eduction pipe communicating with the bottom portion of the container; a first stage pressure reducing regulator connected to the liquid eduction pipe;

a separating chamber communicating with the 25 2,351,131

outlet of said regulator having means to separate the vapor delivered from the regulator from the residual liquid; an underground vaporizer separated trom the storage container and connected to said chamber to receive and vaporize the residual liquid; a super-heating coil connected in series with said vaporizer and arranged within said storage container to absorb heat from the liquid fuel therein; and a second stage pressure reducing regulator communicating with the vapor space of the separating chamber and with said superheater to deliver the combined vapors at service pressure for use in gas consuming ap- LOYD J. WHITE;

permissions orrnn The following references are ot record in the file of this patent:

UNITED STATES PATENTS 'pliances.

Number Name Date 1 2,290,839 White July 21, 1943 2,335,837 Abramson NOV. 30, 1943 Kerr a June3, 1944

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