US2580649A

US2580649A - Liquefied gas discharge pump

Info

Publication number: US2580649A
Authority: US
Inventors: Bludeau Robert Edward
Original assignee: Union Carbide and Carbon Corp
Current assignee: Union Carbide Corp
Priority date: 1948-01-08
Filing date: 1948-01-08
Publication date: 1952-01-01
Anticipated expiration: 1969-01-01

Description

Jan. 1, E BLUDEAU" LIQUEFIED GAS DISCHARGE PUMP Filed Jan. 8, 1948 3 Sheets-Sheet l LIQUID FLOW VAPOR FLOW VAPOR AND LIQQID FLOW C SHUT-OFF INVENTOR OBERT E.BLUDEAU 1 ATTORNEY Jan. 1, 1952 R. a BLUDEAU 2,580,649

LIQUEFIED GAS. DISCHARGE PUMP Filed Jan. 8; 1948 3 Sheets-Sheet 2 I I v 'i 15 ATTORNEY Jan. 1, 1952 R. E. BLUDEAU 2,580,649

' LIQUEFIED GAS DISCHARGE PUMP Filed Jan. 8, 194a 3 Sheets-Sheet s INVENTOR ROBERT E. BLUDEAU BY ATTORNEY Patented Jan. 1, 1952 LIQUEFIED GAS DISCHARGE PUMP Robert Edward Bludeau, Denville, N. J asslgnor, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application January 8, 1948, Serial No. 1,095 17 Claims. (01. 62-1) This invention relates to a process and apparatus for causing vaporizable liquid to be forced out of a container in which it is stored and transported. An object of this invention is to provide a simple and inexpensive device adapted for this purpose so that it will not be necessary to lift or tilt a heavy container. Another object is to provide a process and apparatus of the sort mentioned in which there will be no danger of oil or moisture contaminating the liquid or gas when the same is oxygen. Still another object is to accomplish the intended purpose of pumping cold vaporizable liquid out through the top of a container without having to turn the same upside has been suggested that compressed air be supplied to the upper part of the liquid container to force out the contents. One difficulty is that the available compressed air is not usually dry enough with the result that moisture may freeze in the air inlet of the container forming enough ice to interfere with the supply of air pressure and discharge of liquid. Should any moisture get into the gas it may be objectionable because for example oxygen for breathing is required to be relatively dry. Another objection to the use of compressed air with liquid oxygen is the danger of a little oil being carried along with the compressed air when an explosion might occur due to the presence of oil with liquid oxygen.

Suggestions have been made for the vaporization of enough liquid to create pressure sufiicient to force all of the liquid out of the container. One such suggestion contemplated the removal of some of the liquid by gravity to a vaporizer for generation of vapor pressure to drive out the main portion of liquid. This idea is not feasible here because the liquid containers are too heavy and cumbersome to lift or turn upside down. Another suggestion also impractical here requires suitable suction means for getting an initial amount of liquid out through the top of a container and into a vaporizer where heat is applied from a steam pipe.

According to the present invention neither gravity nor suction is necessary to eject an initial portion of liquid from an upright container and pass the same into a vaporizer. It has been found practicable to generate enough vapor pressure in the container by utilizing the residual heat in a metal ejection pipe inserted into the liquid in the container, to initially force enough liquid out of the container into a vaporizer to start vaporization of a small portion of liquid by heat derived from the atmosphere. Vapor so produced is returned to the vapor space in the container to provide the necessary vapor pressure for the ejection of all the liquid from the container. The vaporizer is preferably mounted on the ejection pipe and on top of the liquid container, and is always exposed to the ambient atmosphere. To insure liquid flow being initiated and maintained a check valve is provided to prevent pressure in the vaporizer from being exerted on liquid surface, thereby preventing flow of liquid down the ejection pipe. To guard against loss of vapor pressure in thecontainer when venting or priming the vaporizer chamber, a check valve is located in the vapor return connection between vaporizer and container. A three-way valve is provided for priming the vaporizer by leading out gas from it to allow liquid to rise easier into it. In normal discharge position (operation) of this three-way valve, the heat of the atmosphere maintains enough vaporization and vapor pressure in the vaporizer and the vapor space in the container to continue the flow of liquid out through the top of the container and past the vaporizer to the place where liquid is to be utilized. At the end of the liquid discharge operation before disconnection of the vaporizer a manually operable pressure relief valve reduces any gas pressure in the container.

Referring to the drawings:

Fig. 1 is a perspective view showing a preferred embodiment of this invention;

Fig. 2 is a line diagram of the apparatus shown in Fig. 1;

Fig. 3 illustrates the three positions of the three-way valve shown in Fig. 2;

Fig. 4 is a vertical longitudinal section through a pump embodying this invention;

Fig. 5 is a top plan view of the pump as shown in Fig. 4;

Fig. 6 is an enlarged section on the line 6--6 of Fig. 5; I

Fig; 7 is an exploded view, partially in perspective, of parts of the ejection tube and its supporting block, showing the liquid and gas passages therein and the means for connecting them.

An improved pump embodying this invention and as diagrammatically illustrated in Fig. 2

includes a liquid ejection tube A, a liquid vaporizer B,' and a three-way valve C, all desirably secured to a coupling block D shown in Figs. 4 and 6. The tube A is constructed so that one end thereof may be inserted through the mouth E of a liquefied gas container F into the body G of liquefied gas therein, and the other end of tube A communicates through passages in the block D with both the vaporizer Band the valve C. The vaporizer B communicates through a tube or passage H to the mouth E with the vapor space I above the liquid G. The tube-A and the vaporizer B also are connected through pipes or conduits J and K respectively with the valveC.

As also shown in Fig. 1, the liquiddischarge portof the valve C is connected by a conduit L tothe 1 inlet of a tank or apparatus M in which; the discharged liquefied gas is to be stored or used. The pump is gas-tightly secured to the container F by a rubber connection or stopper N through which both of the tubes A and H extend.

The container F is of the ordinary portable type customarily used in transporting liquefied gases such as nitrogen,- oxygen, air, etc., the same being thermally insulated according to custom.

Such portable containers vary in size from about into position preferably on top of the container..

From Fig. 2 is may be seen the usual container F is provided with suitable insulation II or the space between the container F and wall I3 may 'be evacuated. Within the insulation are spaced inner and outer walls I2 and I3 respectively, the liquefied gas G being contained within the inner receptacle as illustrated.

When the improved pump is mounted inoperatingposition on the container F, the ejection tube A of brass or other'metal or other heat absorbing material extends from-the vaporiz ing chamber B down into the liquid G to adjacent the bottom thereof. After the tube A has stood in the air and been brought to atmospheric temperature it will have enough residual heat contained within it so that when this tube A is thrust into the liquid enoughof the cold liquid will be vaporized into the'vapor space I above the liquid to force an initial portion of the liquid up through the tube A into a vaporizing chamber B. A brass tube A r for va 100 liter size container F has a heat content of approximately 350 B. t. u. imparted to liquid nitrogen at 320 F. which is capable of forming about 15 cubic feet of vapor at atmospheric pressure and at -320 F. The tube A for the 25 to 50 liter size container gives up around 75 B. t.- u. on immersion in liquid nitrogen and dropping from room temperature. This quantity of heat generates about 3 cubic feet of nitrogen vapor at atmospheric pressure. pressure generated in the container F is'above that of the atmosphere somewhat less vapor is formed than is possible atatmospheric pressure. After being at room temperature again for 10 or minutes the tube A absorbs enough heat to initiate vaporization in another container F.

The vaporizing chamber B is constructed-of.

copper or brass about thick so that heat of the atmosphere will progressively vaporize enough Since the liquid in the chamber B to maintain sufiicient pressure in the container to force the entire liquid contents out ofthe container. The vaporizing chamber B in the embodiment illustrated in Figs. 4 to 6 has a capacity of about 13.3 cubic inches. Where greater heat transmission and rate of vaporization is needed the walls of this chamber may have heat conductive fins not shown. During its passage out of thecontainer F through the top thereof the rest of thecold liquid being discharged rises to adjacent the chamber B but bypassesthe same and is forced out through the valve C and the flexible conduit L to a tank or apparatus M in which the liquefied gas is intended for u'se.'- v

As shown in Figs. 2 and 4 a ball check valve It is provided to prevent the pressure established in chamber B by virtue of vaporization of a portion ofthe liquid, from exerting a force on the liquid in the container F through tube A. In other words, if the check valvewere not provided,the pressure in chamber B and in the gas phase of the container F would be equal, and hence liquid flow could not be initiated, or maintained. The three-way valve C is located. at the junction of the pipe K leading from the up-perportion of the chamber B to the liquid discharge tube L. As shown in'Figs. 2 and 6 another ball check valve I5 is located in the vapor line H' to prevent loss of pressure in the gas phase of container F when the valve C is moved to Prime position for refilling chamber B during a liquid transfer operation. If the pressure in the gas phase were lost, then there would be no way of obtaining liquid in'the chamber B, because during a transfer operation, the liquid ejection tubewould be already at the temperature of the liquid, and could provide no heat for vaporization. Thecheck valves I l and I5 require only a few ounces of pressureto operate'.

In the unitary pump illustrated in Figs. 1 and 4-6, the vaporizer 3 preferably is permanently securedin thermally conductive relation to the top of the coupling block D which desirably is polygonal and made of. copper or brass; the ejection tube A' and elements constituting the lower vapor return passages are detachably secured to the bottom of the blockD; and the three-way valve C is detachably secured'to one side of the block D;

The blockD has a passage 16 extending therethrough to provide communication between the upper .endof the-ejection tube A and a'nipple Il securedto the blockD at the exit end of the passage I6. The nipple I'I extends into the vaporizer B and carries the check valve I4 which is located in a perforate housing I8 mounted on the nipple H. The block D has another passage 19 extending therethroughto provide communication betweenanipple 2S secured to the-block D at the entrance ofthev passage is and extending into the vaporizer Bto supp'ortthe housing 2I of the check valvezi5; passage I9 opens into an annular recess 22 which isconcentric with the entrance end of passage" I6 and is encircled by an externally threaded flange 23' integra'l with the block D. This block D carries 'a pressure relief valve or bursting disc-'39.

A vapor return connector 24 of thermally conductive metal is internally gas-tightly secured to the'outsi'de of the upper end ofthe ejection tube A, with the 'upperends'of the connector 24 and tube'A" disposed inthe same plane. A pluralitylof passages 25' extend from the upper'end At its lower end the of the connector 24 into an annular chamber 26 formed between the tube A and an annular skirt portion 21 of the connector 24. This ejection tube A and connector unit 24 are detachably secured to the block D by an internally threaded nut 28 of thermally conductive metal secured to the flange 23 and by an inturned flange 29 which engages an external shoulder 30 'on the connector 24, thereby establishing communication between the tube A and passage l6, and also between passages 25 and the annular recess 22 which is connected to passage IS. A suitable gasket 3| desirably is clamped between the block D and the ejector tube and connector unit to prevent leakage of liquid and vapor.

A thick rubber tube N is adapted to be fitted around the mouth E at the neck of the container F and when suitably thick is capable of support: ing the entire pump on top of the container outlet as shown in Figs. 2 and 6. This rubber tube N while still enough to support the connector 24, block D, and its connections should also be flexible enough to enable this pump apparatus to be attached to and removed from containers F by an operator without difliculty.

Leading off from the passage 16 is another passage J in the block D through which the main body of liquid from the container F passes without it entering the vaporizing chamber B on its way to the apparatus M. Welded or otherwise secured in passage J and to the block D is the fitting 33 to which the three-way valve C is secured. On the opposite side of the valve C is a nipple 34 to which a nut 35 secures the conduit L. Welded into the upper end of the vaporizing chamber B is a conduit K having its lower end threaded into the top of the valve C.

In operation after the pump has been placed on a liquid container filled with liquid nitrogen or other liquefied gas, the residual heat in the tube A vaporizes enough liquid to increase the vapor pressure in the vapor space I above the liquid level in the container F to force liquid G from the container F up the tube A into the vaporizing chamber B. Vapor pressure in this chamber B is maintained by the heat of the atmosphere penetrating the thermally conductive metal walls of the chamber B and vaporizing some of the liquid therein. To provide additional vapor pressure in the container F after the heat of the tube A has been largely absorbed, the vapor pressure in chamber B is transmitted to the vapor space I in container F through the tube H and vaporization in chamber B though at a slow rate is suflicient to maintain enough vapor pressure in the space I to force out substantially the entire body of liquid in the container F through the conduits J and L to the apparatus M in a continually flowing stream. 01' of course the liquid in the container F may be pumped out intermittently instead of uninterruptedly if desired. As the initial body of liquid in chamber B is consumed more liquid may be needed. Since the vapor pressures in the chamber B and container F are equalized, no additional liquid automatically flows into chamber B. To raise the liquid level in chamber B the handle 41 of the three-way valve C is moved to the priming position shown for it in Fig. 4. As shown by the upper portion of Fig. 3, this connects conduit K leading from the upper portion of chamber B to the conduit L leading to the apparatus and causes vapor pressure in chamber B to fall gradually. The check valve I5 prevents vapor flowing from space I into chamber B withthe result that pressure inspaceI forces liquid up the tube A raising the liquid level in chamber B. The increased level of liquid in chamber B may be:determined roughly'by approximating the time during which the valve C is allowed to remain in the Prime position, by estimating the liquid flow to the apparatus M, or in any other desired manner.

After the level of liquid in chamber B has risen to the desired amount valve C is moved clock- Wise as shown in Fig. 4 to the Fill position.

The valve C remains in this position as long as the pump needs to force liquid into the apparatus M. .7 I

To shut off the liquid flow to apparatus M the ivalveC is moved to the Shut-off position 90 further in a clockwise direction fromthe Fill position asshown in Fig. 4. As illustrated in Fig. 3, this connects conduits J and K. The pull ring 38 is moved out or to the left in Fig. 4, venting pressure in the space I and in chamber B as valve [5 allows'any higher vapor pressure in chamber B to flow into space I. Low vapor pressure in both chamber B and space I causes any small amount of liquid in the' tube A and conduit J to flow back into the container. However, any liquid in chamber B does not flow back due to check valve I l allowing liquid to flow only into and not out of chamber B. The pump is then removed from one nearly empty container F and put in place on a filled one. When the rubber connection has been put in place forming a gas tight connection thenas vaporization occurs inchamber B, liquid rises due to vapor pressure in the vapor space I of the new container rather than from the heat of the tube A. The valve C should be in a Prime position on the new filled container until pressure recorded by the gauge 45 is sufficient to begin the pumping operation and while the liquid level in chamber B is below the top of housing 2|. If desired the tube A may be exposed to the atmosphere long enough to utilize its heat in initiating vaporization of a filled container F, or it might be placed over or in a heater to raise its temperature.

Although vaporization in the chamber B from heat of the atmosphere is slow, it is sufiicient to sustain enough vapor pressure in container F for the discharge of liquid to be continuous until the containeris empty. When the chamber Band tube are at room temperature, only a few seconds are needed to fill chamber B with liquid from the container. is placed on a new or filled container after emptying a former one, thenwhen enough liquid is retained in the chamber B, a few minutes delay is needed to cause vaporization in chamber B to generate suflicient pressure for continuous dtischarge of liquid from the container F to empty 1 Among the advantages of this invention may be mentioned the provision of an inexpensive pump apparatus which is quickly and easily installed and removed from containers of liquefied gas of customary construction. The tube by which, heat is supplied to the liquid and by which liquid is removed from the containers are one and the same. After the initial discharge of liquid due to the residual heat in the tube A, further pumping of liquid continues due to the supply of heat from the atmosphere through the thermally conductive walls to the chamber B causing vaporization of liquid and transfer of vapor pressure into the container F. After starting the ejection of liquid from the container by the residual heat of the tube A the gentle sup- When the pump apparatus ems-once;

ply of heat needed to maintain the ivaporopresaz sure required in the top of the container F113". prefierably obtained: in the simplest: and" least:

expensive manner from the atmosphere "although of course shouldmore heat be desired at anytime a small additional heat supplysuch' as the'heat of a lampor candle may be applied to: the vaporizen Pressure relieifrom' the container and: chamber is either automatic or manual by means of the relief valve- 31. Movementof the three-way valve-C to its priming? position at any time enables liquid to rise-in the chamber B. A noteworthy advantage of the present invention is the simple and-inexpensive eliminationyof the hazard and disadvantages:

of oil or moisture in compressed air when using the latter to .dischargeliquid. This -pump'apparatus; may 'be left on a container F overnight or-over a weekend. When no liquid is being consumed there need, be no similar vaporizavalve-31 within safe limits. At a setting of 7; pounds per square inch maximum pressure this apparatus pumps liquid at a rate of 1.5gallons per minute.

A shut-off valvein thevapor line H would be useful in holding vapor pressure in the vaporizing chamber when the pump is transferred to another container, although it would necessarily detract from the appearance. In its form illustrated-thepump can be moved'fromone container to another'with a full chamber of liquid nitrogen,. which because of. the ratio of expansion between liquid and vapor, will provide more pressure for the secondcontainer. For example,

a full chamber of liquid is capable of producing approximately 450 times as much vapor, comparedto a full chamber of vapor at 7 pounds per.

square inch.

1; Apparatus for pumping vaporizable liquid froma container. under vapor pressure which comprises a liquid ejection tube of thermally conductive metal adapted to extend into said container, a gas tight connection through which said tube is adapted to enter the top of said container, a closed chamber of thermally conductive metal exposed to the atmosphere outside said con tainer and'to which said tube is connected for the discharge of liquid from the container into saidchamber,- a vapor passage from an upper portion of saidchamber and adapted to entersaid co'ntainer through said gas tight'connection, a conduit from said tube through which said liquidis adapted to pass from said containerto its place of use, and a check valve locatedin said. tube between .its discharge into said. chamber. and the connection of said conduit and tube, whereby liquid-may flow from the container into said.

chamber but not from thechamber into the containeror to its place of use.

2. Apparatus according-to claim 1 in which .a check-valve is located-in said vapor-passageto pass vapor in only the one direction from the chamber into said container.

.3. Apparatus according-to claim 1 in which a.

sageitdprevent excessive-vapor pressure inisaid;

chamber and in saidacontaineri 4. Apparatus for pumpingmvaporizable liquid from a 4. container -underui .vapor :pressureaiwhichr comprisesa liquid ejectiontubeof thermallyconeductive meta'Ladapted-to extend iIItO-SaiGACOII-E. tainer, a gas-tight connection through whichrsaid' tube isadapted to ententhe top of said containem a closed chamber. of: thermally conductiveemetal l exposed to the atmosphere outsidesa-id container; andto which said. tubelis connectedfor the charge of liquidL-irOmJthe container into... saith chamber, a vvaponpassage;from an .upper portion: of said chamber. andizadapted to entersaidcone tain'er. through said-gas-tight econnectiomva iconduit 1' through whichv said liquidlis adaptedto pass. fromsaid container to its place .of.use,--the heatin said ejection tube being ;at room temperature; thevolume of. saidcontainer when. filled: with liquid oxygen; liquidxnitrogen, or. liquid air,the 1 volume of containervaporspace, and the height 5 to which the liquid'fromsaid container: must 'be' raised inireaching said closed chamber being sov proportioned that heat from said-ejection tube isadaptedto vaporize some-liquidin the container and raise the vapor pressure in the-container to force liquid into said closed-chamber for starting vaporization therein from the heat of the atmosphere,. valve means-:for opening and closing saidconduit to the movementof liquidtherethrough, and a second conduit between said chamber and"; valve means whereby said valve means is operable-- to vent vapor therethrough from said chamber.

5. An apparatus for pumping vaporizable liquid 1; from a container under vapor pressure without. danger of ice formationfrom .moisture in the vapor under pressure which comprises, a liquid ejection tube of thermally conductive material adapted to extend through'the top of andinto. said container to adjacent the bottom thereof, 'a closed chamber of thermally conductive metal outside saidcontainerconnected to said t'ube, a vapor: passage. from :an upper-portion of. said chamber adapted to extend into said-container, a vapor-tight connection-for said tube andxpas sage where they are adapted to enter the top of said container, and a conduit from said tube through which aliquidfrom said containeris adapted-to pass 'to' its placeof use,--said vapor passage and tube being substantially concentric wherethey are adapted to passinto the container, a check valve in the liquid line from the container to said chamber, a check'valveinsaid vapor passage from the chamber to said container, and a-' relief valve connected to said gas passage whereby vapor pressure in the containermay be vented before removal'of the tubefrom the container.

6. Apparatus for pumping a vaporizable liquid out thetop of athermallyinsulated container. which comprises a liquid ejection tube adapted to extend adjacent the bottom of the container; a vaporizing chambei connected to said tube, a liquid discharge passageleading from said tube, a vapor passage extending from an upperportion of said chamber andadapted .toenter said .con-.. tainer, a conduit-leading from theupper end por-- tion of said chamberto said liquid discharge pas-' sage adjacent the chamber, and a three-way valve at the function ofsaid chamber tube and liquid discharge passage-adapted in one position to ventv vapor-from the upper portion of said-chamber out; the discharge passageinanother position to connect said liquidejection tubewith .said -dis--- charge passage and in. still another position to connect said chamber conduit and liquid ejection tube.

'7. Apparatus for pumping a vaporizable liquid out the top of a thermally insulated container which comprises a liquid ejection tube adapted to extend adjacent the bottom of the container, a vaporizing chamber connected to said tube, a liquid discharge passage leading from said tube, a vapor passage extending from an upper portion of said chamber and adapted to enter said container, a pressure relief valve in said vapor passage, a chamber tube leading from the upper end portion of said chamber to said liquid discharge passage adjacent the chamber, a three-way valve at the junction of said chamber tube and liquid discharge passage adapted in one position to vent vapor from the upper portion of said chamberout the discharge passage, in another position to connect said liquid ejection tube with said discharge passage, and in still another position to connect said chamber tube and. liquid ejection tube, a check valve in the liquid ejection tube within the vaporizing chamber, and a second check valve in said vapor passage and in said chamber.

8. Apparatus for pumping a vaporizable liquid out the top of a thermally insulated container which comprises a liquid ejection tube adapted to extend adjacent the bottom of the container, a vaporizing chamber connected to said tube, a liquid discharge passage leading from said tube, a vapor passage extending from an upper portion of said chamber and adapted to enter said container, a pressure relief valve in said vapor passage, a chamber tube leading from the upper end portion of said chamber to said liquid discharge passage adjacent the chamber, a three-way valve at the junction of said chamber tube and liquid discharge passage adapted in one position to vent vapor from the upper portion of said chamber out the discharge passage, in another position to connect said liquid ejection tube with said discharge passage, and in still another position to connect said chamber tube and liquid ejection tube, and a spring responsive and manually operable pressure relief valve in said vapor passage between said chamber and container.

9. Apparatus for pumping a vaporizable liquid from a thermally insulated container through an opening in the upper portion thereof without having to tilt or invert the container, said apparatus comprising a liquid ejection tube adapted to extend into said container through said opening, a vaporizing chamber to which said tube is connected outside said container for receiving heat from the atmosphere and vaporizing a portion of said liquid received therein, a check valve in said tube allowing movement of the liquid from said container but not from the chamber to said container, a vapor passage from an upper portion of said chamber to an upper portion of the container, a gas tight connection where said tube and passage enter said container, a check valve in said passage allowing movement of vapor from said chamber to the container but not from the container to the chamber, means for venting vapor pressure from the container, means for venting vapor pressure from said chamber and a conduit from said tube between said chamber and container, leading to the place where said liquid is desired.

10. Apparatus for extracting a liquefied gas from a thermally insulated container under vapor pressure, which comprises a liquid ejection tube of thermally conductive metal adapted to extend into a containerhaving a reduced neck through tainer but allowing neither pressure nor liquid to "be discharged from said chamber into said container, a pressure discharge pipe extending from an upper portion of said chamber through said means for projecting into an upper portion of a container and a check valve in said pressure discharge pipe allowing pressure above a predetermined amount in said chamber to be transmitted into a container but not from said container into said chamber.

11. A method of pumping liquefied gas from a thermally insulated container without having to lift or tilt the container and without having to have a pump with moving parts, said method comprising initiating vaporization of some of the liquid by the residual heat in a thermally conductive metal liquid ejection tube, ejecting liquid by pressure of the portions of the liquid vaporized by the heat of said ejection tube, vaporizing outside of the container a portion of the ejected liquid apparatus including an ejection tube, a gas-tight connection through which said tube extends 'whereby liquid is raised out of the container,

a vaporizing chamber connected to said tube and in which a portion of the vaporizable liquid is heated, and a vapor return passage from said chamber through said gas-tight connection to the container, the combination therewith of the improvement for simplifying said apparatus, said improvement including said ejection tube being of at least as highly heat conductive material as is brass and having a heat content of at least about 350 B. t. u. when at the temperature of the atmosphere for a 100 liter size container and about B. t. u. for a 25 to 50 liter container, whereby the heat of said tube is adequate to vaporize some of the container liquid and create a vapor pressure to raise some of the liquid out of the container through said tube and into said chamber.

13. An apparatus according to claim 12 in which said vaporizing chamber is of a heat conductive material at least substantially as high as that of brass whereby heat of the atmosphere vaporizes liquid in said chamber to maintain pressure in the container for forcing out the liquid from said container, and a conduit for discharge of liquid from the container by-passing said chamber.

14. In an apparatus for pumping vaporizable liquid from a thermally insulated container, said apparatus including an ejection tube, a gas-tight connection through which said tube extends whereby liquid is raised out of the container,

' wazvaporizing :c-hamber iniwhich a. portion of; the :vaporizable liquid, is heated,,.-and a, vapon-return passage from said chamber to saidacontainer, thewcombination, therewith of the improvement liquid to maintain-vapor pressure in the container for forcing all ofsaid liquid out ofthecontainer,

,. valve means in said tube responsive to high -pressure in said chamber to prevent vapor pressureinsaid chamber forcing liquid in said tube backinto the container, valve means in said .;vapor-return passage responsive to high pressure min-said container to prevent higher pressure in ,-the. container-moving vapor into said chamber :when .at a lowerpressure, and valve means for by-passing both of said previously mentioned .valve means.

15. Alight weight portable liquid pumping unit for mounting on and to be carried by and above an insulated container of, liquefied gas, said unit comprising a gas-tight connection for attach- "ment to the mouth of said container, a thermally conductive-ejection tube passing through said r-connection wherebyheat of said tube mayinitiate-vaporization of liquid in said container, naathermal-lyc conductive vaporizing chamber surimountingcsaid tube forreceiving liquidinitially ,forcedout of said container by vapor pressure generated from the heat of said tube, and for yvaporizing liquid innsaid, chamber by theheat of the atmosphere, a vapor return passage from said-chamber passing through said connection to extend into said container, and a liquid disucharge conduit-extending from. said unit between 1 saidconnection and said chamber. lfi A pumpingunit according :to. =claim in which. said connection includes an elastic sleeve i*,l:i roug h--.which said-tube-and-passage are concentric, anvalve being-located in saiddischarge aconduit at one side ofsaid unit, a pipe connecting said valve, and chamber, said valve having at leastthree-positions, .in-one of whichsaid disachargec-conduit beyond said valve.is; connected vaporizing temperature adjacent that of liquid oxygen-from acontainer-without having to tilt or invert such container which-comprises-inserting an ejection'tube of heat conductive material at a-temperature well above that of the liquid into the liquid, transferring-heat of said tube to said liquid to-vaporize'some of the liquid, creating avapor pressure in the container from such cheat transfer,:forcing.-some of the liquid out of the container through said tube by said vapor --prssure into a vaporizingchamber, absorbing discharging liquid.

, Number ROBERT EDWARD BLUDEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Andrews May 23, 1922 Lisse June 19, 1923 Leach Apr. 12, 1932