US2535364A - Liquefied gas storage system - Google Patents

Description

Dec. 26, 1950 Filed July 26, 1946 M. W. LEE

LIQUEFIED GAS STORAGE SYSTEM 2 Sheets-Sheet I.

I wi I'l'i 1| W l li I H lu i h li Q I 1 w.gl nii iahnlw' ATTORNEY 1950 M. w. LEE 2,535,364

LIQUEFIED GASSTORAGE SYSTEM Filed July 26, 1946 v 2 Sheets-Sheet 2 F l G 2 )flgur/Ct L1 INVENTOR,

ATTORNEY I Patented Dec. 26, 1950 UNITED STATES PATENT oFFloa LIQUEFIED osz s fsitaoa SYSTEM Application July 26,1946, Serial No. 686,376

2 Claims. 1

, My invention relates to absorption type reirigeration. and more particularly to a refrigerator or refrigerating system operable in conjunction with a fuel system utilizing a liquefied petroleum product. such as butane, propane, isobutane or a combination thereof.

The principal object of the invention is to utilize as a refrigerant, the latent heat of vaporization which normally is expended uselessly.

For instance, liquefied butane during evaporation or gaslfication absorbs at sixty degrees F., approximately one hundred sixty B. t. u. per gallon. Two-hundred gallons of liquefied butane absorbs over 160,000 B. t. u. in conversion to a vapor state. This heat absorption is suflicient to lower the temperature of two tons of water by 40 degrees F. g

Since it is common practice to bury butane storage tanks. the heat of evaporation is normally absorbed from the surrounding'earth, and of course, in above-ground storage tanks, the heat is merely absorbed from the surrounding atmosphere. The present invention is designed to utilize as a refrigerant. the normal evaporization of such liquefied petroleum gases.

Gasifled butane liouefies at approximately 32 degrees F., and in cold climates, liquefication in the service line of butane fuel systems causes flow stoppages and plant failures. In order to combat such conversion of gas to liquid, it is common practice to equip such fuel systems with a heat exchange means for re-converting the liquid back into its gaseous state. Such means are usually more or less expensive.

An important object of the present invention is to util ze the heat absorbed in the refrigerating portion of the system to prevent the gaseous butane from returning to its original liquefied form, thereby eliminating the necessity of providing a usual re-converting medium. 1

Another object of the present invention is to obtain a more rapid evaporation of the liquefied gas by utilizing it both as a refrigerant and as a fuel, thus promoting efliciency'and economy.

An additional object is to provide a combination refrigerating and fuel conveying system which is automatic in operation.

Other objects and purposes will be apparent from the following description when taken in conjunction with the accompanying two sheets of drawings, wherein:

Figure 1 is a schematic elevational'view, partially in section; and,

Figure 2 is a vertical sectional a combination heat absorber and generator unit forming a part of the invention.

Like characters of reference designate like parts in those figures of the drawings in which they houses fluid flow control valves, tank filling pipe view I detailing 56 connections, etc.', which have for the purpose of clarity been deleted from the present drawings. A usual outlet line 3, leads from the dome 2 for the purpose of conveying gasified fuel to a point of consumption, not shown, but before reaching such point, of consumption, the fuel gas passes through a usual pressure differential valve 4 and a pressure regulator 5, to a service line 6. The service line 6 then conveys the fuel to such point of consumption. In usual butane storage tanks, as well as in the tank ofthe present system, the upper portion of the tank is filled with an accumulation of gasified butane. This space in the tank is indicated by the reference numeral 1.

In carrying out the present invention, the following described apparatus is provided.

The bottom of the tank I has a liquid outlet pipe It! in which is installed a usual excess flow or velocity control valve II. The line H) leads from the valve ll through a suitable flow control valve l5 to one end of an evaporator [2, the other end of which is connected to a pipe l3 leading to a second pressure differential valve I4 which is connected at its other side to-the gas outlet line 3. Of course, the evaporator 12 may be located at ony point at which it is desired to lower the temperature of an area of atmosphere. The liquid gas in the line [0 is converted to gaseous form in the evaporator l2, and it is therefore in such gaseous form when it reaches the service line 6. The line I0 is preferably provided with said manually operated cut-on valve l5 whereby the evaporator llmay be eliminated from the system.

Pressure differential is accomplished between the line In and the line l3 by any suitableand conventional means which commonly accompany liquid evaporators, such as the evaporator I2. Such means may well be a liquid float or an expansion valve, and since such means are conventional, it has not been shown in the drawings nor described herein.

A heat producing unit or generator I5 is provided at a desired point in the system, and consists of a vertically disposed cylindrical tank having an axial tube or vent I'I passing entirely there-through so as to create an annular space I! within the tank. The annular space I3 is bridged heremetically by two vertically spaced septa I 9 and 20. The portion of the space l3 below the septum i9 and above the bottom of the generator is adapted to be filled with oil 2|, and an open ended percolator tube 22 extends heremetically upward through the two septa l3 and 20 from a point adjacent the floor of the generator. The upper open end of the tube 22 lies adjacent the closed top 23 of the generator tank It.

Adjacent the generator I8 is provided an absorber unit 25 which consists substantially of a vertically disposed cylindrical tank having a closed top 28 and bottom 21. Interiorly, the absorber tank 25 is provided with a plurality of vertically spaced transverse plurally perforated baiiie plates 23, and exteriorly, it has a plurality of heat transfer fins 29. A gravity flow pipe 30 leads from the upper chamber of the generator I. to the top of the tank 25, and the lower chamber 01' the generator communicates with the bottom of the tank 25 through a pipe 3|. The top 23 of the generator has an outlet pipe 32.

The pipe l3 leading from the evaporator I! has a branch pipe 33 which carries gaseous butane to the bottom of the absorber tank 25, for a purpose more'fully described hereinbelow.

As a means for heating the oil.2l in the generator It, the branch pipe 33 is equipped with a flow pipe 34 leading through a conventional pressure regulator 33 and a thermostatic valve 33 to a burner 31 located beneath the generator.

With the burner 31 ignited, and the oil 2| heated to a boiling point, sufilcient oil pressure is built up in the generator to cause the oil to rise through the percolator tube 22 and be discharged from. its upper end into the absorber tank 28. The hot oil may gravitate through the tube 30 to the upper portion of the absorber 25, and through gravitation will percolate downwardly through the plurally perforated bailie plates 23 to the bottom of the absorber. From the bottom of the absorber, the oil may return through the pipe 3| to the bottom of the generator. This circulation of oil will be continuously maintained so long as the burner 31 is ignited. Obviously, any gas which is contained in the oil as it discharges from the upper end of the percolator tube, will be released from the oil at the point of discharge into the upper chamber of the generator l3, and will leave the generator through the gas outlet pipe 32.

The gasiiled butane which enters the lower end of -the absorber tank 25 through the pipe 33, will be entrained in the circulating oil therein. Any of such gas which is absorbed by the oil is released, as described hereinabove, when the oil is discharged from the upper end of the percolator tube 22.

As a means for furnishing fuel gas to a pilot light 39 adjacent the burner 31, the service line I is tapped by a line 39 which extends downwardly therefrom and through 'a cut oil valve 40 to its pilot light end. A heat conducting wire 4| leads from adjacent the pilot name 33 to the thermostatic valve 36. in the fuel line 34, so that at'any time the pilot flame ceases to burn, the valve 33 will automatically cut oh. the supply 01 fuel gas to the burner 31.

The gas which leaves the generator l3 through the outlet 32 enters a condenser or heat exchange element 42 wherein it is cooled to such an extent that it liquei'iee and returns to the storage tank I through a back pressure valve It in a pipe 43. Gas condensation in the condenser 32 may also reach the storage tank I through a pipe 44 leading from the outlet pipe 32,

In cases in which the storage tank I has sumcient superficial area to cool the hot gas therein to a point 01' liqueflcation, the condenser 42 and pipe 43 may be dispensed with, and only the pipe 44 will be used.

The pressure differential valve 4 is so regulated with relation to the similar valve I, that gas will be delivered to the service line 3 through the line l3 as long as the supply is suilicient to meet the demand of such appliances as are connected to the service line. When such supply is insumcient, then the valve 4 will automatically open to supply from the pipe 3, such additional gas as required tomeet the demand.

It is pointed out that any gas, either in liquid or in vapor form, which does not pass to the service line 6 for fuel consumption, automatically flows through the line 33 to the bottom of the absorber unit 23, and eventually returns to the tank I.

It is thought to be apparent that the above described apparatus is capable of accomplishing all oi the objects and purposes set forth hereinabove, and that operation thereof has been made sufliciently clear to enable one versed in the art to use the same.

Obviously the invention is susceptible-to some change or alteration without defeating its practicability, and I therefore do not wish to be conlined to the preferred embodiment shown in the drawings and described herein, further than I am limited by the scope of the appended claims.

I claim:

1. The combination with a tank for storing liquefied petroleum gas and with an outlet line for evaporated gas leading from the upper portion of the tank to a fuel gas service line, of: an evaporator having one end connected to said tank below the liquid level therein; a flow line leading from the other end of said evaporator to said service line; means for conveying gas from said new line when the service line is closed; means for increasing the pressure of said gas; an oil bath for absorbing the. gas; a unit for heating the gas entraining oil to cause the gas to be released from the oil at an increased pressure; means for converting said gas into liquid form; and means for returning the liquidto said tank.

2. Structure as specified in claim 1, in which the converting means includes a temperature reducing unit through which the released gas passes before its return to the tank.

MAURICE W. LEE.

REFERENCES orrEn The following references are of record in the tile of this patent:

UNITED STATES PATENTS Fish Nov. 30, 1937

Images