US2180090A - Method and apparatus for dispensing gas material - Google Patents

Description

Nov. 14, 1939. w. F. MESINGER METHOD A'ND APPARATUS FOR DISPENSING GAS MATERIAL Filed Feb. 18, 1956 3 sheets-sheet 1 ATTORNEYS Nov. 14, 1939. w. F. MESINGER 2.180,09()

AND APPARATUS FOR DISPENSING GAS MATERIAL Filed Feb. 18, 1956 3 Sheets-Sheet 2 INVENTS@ MEW ATTORNEY S Nov. 14, 1939. w. F. MEslNGER 2,180,090

`METHOD AND APPARATUS FOR DISPENSING GAS MATERIAL Filed Feb. 18, 1936 3 Sheets-Sheet 3 ocu ATTORNEYS Patented Nov. 14, 1939 I PATENT "omcs ,METHOD ANDAPPARATUS Fon nIsPENsING` y o GAS MATERrAL William F. MesingergMount Vernon, N. Y., as-

signor to The Linde Air Products Company, New York, N. Y., a corporation of Ohio Application February 1s, 1936, serial No.I 64,487

18 Claims.

This invention relates to a methodvand apparatus for dispensing gas material and particularly to a method and apparatus for dispensing and' regasifying liquefied gases which have boiling low 273`K.

The invention has for itsv principal object generally to provide a method and apparatus for dispensing gas materials of the character inperature and pressure that the transfer of the.

gas material from the production plant to receiving containers at relatively high pressure is accomplished with relatively small losses.

It is still another object to provide means for transferring liquefied gas to a vaporizer at relatively high pressure utilizing linjector action.

3() Other objects of the invention will in part be obvious yand lwill in part appear hereinafter.

The invention accordingly comprises the several lsteps rand the relation of one or more of such steps with respect to each of the others,

and the apparatus embodying features of the construction, combinations of elements and arrangement of parts which are adapted toeffect such steps, all as exemplied inthe following detailed disclosure, and the scope of the inventionvwill be indicated in the claims.

. For av fuller understanding objects. of the invention reference should be had to the following detailed descriptiontakenin AconnectionLwith the 'accompanying'. drawings, in

which:l 4

' Fig. l. is an yelevational view. partly vinl section showing anarrangement. of apparatusfuat lthef 5o Fig. 2 is a similar viewofa form of apparatus` for transferring liquefied gas by injector action and Iconverting it'finto'v gas of'l desired pressure;

Fig. 3ds asimilarvie'w of still ,another form.

of vapparatus"in which ,the liquid isQtransferred 'by injector action;

point temperatures at atmospheric `pressure be-` of the nature and Fig. 4 is a similar view of another form of the apparatus in which the liquid is transferred in two stages to the vaporizing means in accordance with the present invention; l

Fig. 5 is a similar view of another form of ap- 5 paratus for transferring liquefied gas by)= gravity flow to a warm converter, such as is disclosed in U.l S. patent to Heylandt, Reissue 18,476; and

Fig. 6 yis a similar view of another form ofapparatus for transferring liquefied gas by mechani- 10 cal forcing means into vaporizng means as disclosed in U. S. patent to Heylandt, Reissue Liquefied gases whichare handled at temperatures below 273 K., such, for example, as liquid 15 oxygen, have been stored and transported at substantially atmospheric pressure in vessels which are insulated fromthe influence-of external heat and, since, in practice,y the insulation is not perfect, there was a continuous evaporation r'of 20 liquid within the vesselsv at a slow rate ,caused` by the heat that leaksv through to the liquid.` Vapors so produced during transportation have been lost. When the liquid is transferred from one container to another, and particularly `when 25' it is transferred to vaporizers for converting into gas of a desired high pressure, further losses of gas have occurred as the tendency of a portion of the liquid to flash into vapor is great when the liquid is at its boiling temperature at the prevail- 30' vthe normal periods for which the' liquefied' gas is stored or transported. The liquefied gas thus produced is thentransported toftli'e place ofl use `in a closedcontainer Whichis preferably maintained undera sub-:atmospheric pressure.'v

`,The gas material, heretofore lost ,tothe atmosphere duringatriptov the'place of use, according to the present method is conservedg- In Laccorn-` plishing this, the gasgmaterial whichfnormallyV 5o arises by evaporation inthe storage"containerat` theproductionplant is now withdrawnkland presl sed into g'asholders, suc'h `as cylinders; or reliquefied.` Also, in thel furtherance of "this eri'd, both `the storage container and thetran'sport container 5 are insulated against heat leakage as completely as practical. To enhance the insulating value of the material normally employed it is here proposed to iill the interstices in the insulating envelope of the containers with an insulating gas that in the liquid phase has a boiling point at the pressure maintained in the insulation which is below the temperature to which the liquefied gas in the container is cooled. For example, when the liquid in the container is liquid oxygen, the interstices of the insulation are advantageously filled with gaseous nitrogen, or with air if maintained at a pressure suiiiciently reduced to avoid the condensation of oxygen.

Referring now to the drawings and particularly to Fig. 1, there is illustrated according to the invention several items of equipment located at a liquid oxygen production plant and arranged cooperatively for the practice of the present method. A column for separating oxygen from air and providing the oxygen in the liquid state of a high degree of purity is shown generally at I0, which delivers the liquid to a closable insulated storage container or tank shown generally at II. A second closable container or vessel upon a vehicle is shown generally at I2 for transporting the liqueed gas connected to the storage tank for receiving a charge of liquid to be transported to a place of use. At I3 is shown generally an apparatus for compressing gas evaporated from the liqueed gas into pressure storage containers.

The column I0 is supplied with compressed and processed air through conduits I4, while the gaseous nitrogen product of the separation is discharged at I5 and the puried liquid oxygen is discharged through conduit I6. A portion of the column casing is broken away to show a conduit I'I that conducts gas material from the lower portion of the column for discharge at an intermediate point into the upper portion of the column. The flow through the conduit I1 is controlled by a regulating valve I8 located at the upper end of the conduit and discharging into the nozzle of an aspirating device I9, which draws gas out of a conduit 20 connected to the suction chamber of the aspirator. 'Ihe combined gas materials are discharged into the column through the discharge portion of the aspirator, which is in communication with the interior oi the column.

The storage tank comprises a main inner vessel 2| and a smaller auxiliary vessel 22 located above it and both surrounded by a. common insulating envelope 23, which is externally supported by a casing 24. The insulation pores and spaces are lled with nitrogen which is led into the casing 24 by a conduit I54 providing free communication between the casing and the nitrogen discharge conduit I5, so that a ilow of anhydrous nitrogen may pass in or out of the casing as the gas expands or contracts in response to temperature changes. The vessels 22` and 2| communicate through a connection joiningv the bottom of vessel 22 and the top of vessel V2|. which is controlled by stop valve 25, 'I'he conduit I6 having a stop valve 26, joins the upper portion of the auxiliary chamber 22 for leading the. liquid oxygen therein as it is produced. The gas spaces of the two vessels are also joined by a conduit 21, which conducts gas from the upper portion of vessel 2|, passing it through a Aportion coiled around the vessel 2l within the insulating venvelope 23 to the upper portion of vessel 22.' This flow is controlled by a stop valve 23 located in the portion of conduit 2l nearest vessel 22. A device for rapidly vaporizing a portion of the liquid to provide a temporary increase in pressure above the liquid in the vessel 2l comprises e conduit 29 having a portion 30 exposed to and arranged to be heated by the atmosphere and connected at points above and below the upper surface of the liquid in vessel 2I. A stop valve 3l at a point in the conduit close to the vessel is provided to control the flow of liquid into the conduit when desired.

Several means for drawing off gas from the top of vessel 22 are preferably provided. One such means comprises a centrifugal exhauster 32 driven by an electric motor 33, the intake of the exhauster being connected in communication with the top of vessel 22 through a conduit 34 and its exhaust with conduit 2U, which is controlled by a valve 35 and has a branch 36 controlled by valve 31 communicating with the portion between valve 35 and the discharge of exhauster 32. The exhauster 32 may be of the single or multiple stage type adapted to provide the desired pressure diierence between its intake and discharge. The branch conduit 36 conducts gas when desired to a relatively low pressure storage holder, for example, a gasometer.

Another means for drawing oil? gas is shown at I3 and comprises a gas compressor 38 here shown diagrammatically as of the single stage type, but which may be of the multiple stage variety when desired to compress gas toa relatively high pressure. Gas is conducted to the intake of the compressor through conduit 39, which communicates with conduit 34 and is controlled by a valve 40. 'I'he conduit 38 is provided with an extended coil portion that is immersed in a heating iiuid contained in a vessel 4I. A iiuid for lubricating the piston and packing of the compressor is added to the gas admitted to the cylinder by means of a lubricant feeding device 42 communicating with the conduit 39. When the gas is oxygen, a suitable non-combustible iluid is fed, for example, water. The compressor discharges through a conduit 43 that leads into a trap or separator 44, provided for separating lubricant from the compressed gas. If desired, moisture in the vapor state may also be removed by causing the gas to contact with moisture-removing chemicals held in trap chamber 44. The compressed gas is carried from the trap by a manifold conduit 45 into the high pressure cylinders 46 communicating therewith. Thus gas may be drawn from vessel 22 through conduits 34 and 39 to be compressed and stored at high pressure in cylinders 46. More effective moisture removal by trap 44 may be had by cooling the compressor discharge by heat exchange with cold gas passing through conduit 39.

The liquid transport device at I2 comprises a motor truck 41, upon which is mounted a liquid container and its auxiliary equipment. 'I'he liquid is carried in a closed vessel 48 disposed within heat insulation 49 supported by an outer casing 50. The liquid is conducted into the vessel 43 by means of filling conduit 5I which leads to a. point near the bottom of the liquid space and is provided with a stop valve 52 and a coupling 53 at a point external to the casing 50. The coupling 53 is joined by a section of iiexible conduit 54 to a similar coupling 55 located at the external end of a conduit 56, which depends into the liquid in the storage vessel 2I. Flow from the conduit 56 is controlled by a valve 5'I interposed at a point close to coupling 55. The liquid spaces of vessels 2l and 48 can thus be placed in communication through conduits 56, 54 and 5I. Means for rapidly developing a pressure in the vessel 48 is also provided and comprises conduit 58 having a portion exposed to the heat of the atmosphere and in communication With both the liquid and gas spaces of the vessel. Vessel 48 is also provided with the usual devices sugh as safety release valves and liquid level gauges. Admission of liquid to conduit 58 is controlled by a valve 59, shown as having an extended operating stem. A branch of conduit 58 leads to a coupling 60 located at the rear of the truck and normally sealed by a blank cover. A stop valve 6I is inserted in conduit 58 to be closed when it is desired to permit liquid to iiow only through the branch leading to coupling 6I). For drawing oil" gas there is provided a conduit 62 leading from the gas space of vessel 48 to the inlet of an exhauster 63, whose rotor is connected to and driven by an electric motor 64. The motor draws its electric energy from any suitable source, for example, from the storage battery carried by the truck. It is contemplated, however, that the exhauster may be mechanically coupled, for example, through gearing, to be driven by the propeller shaft of the truck, or by a power take-off shaft of the engine. The conduit 62 is provided with an extended coiled portion within the insulation 49, so that gas iiowing out of vessel 48 may impart refrigeration to and draw heat out of the insulation. The exhauster discharges through a. conduit 65 which is joined to a flexible conduit 66 by means of a coupling 61. Flow through the conduit 65 is controlled by a valve 68 and a bypass connection controlled by a valve 69 is provided;from conduit 62`to conduit 65 to be opened whenit is desired that gas should flow out without p ssing through the exhauster 63. Coupled to conduit 66 by means of coupling 10 is a conduit 1l controlled by a valve 12 and communicating with conduit 21. A branch conduit 13'having a valve 14 communicates with conduit 1I at a point between valve 12 and coupling 1l) and with conduit 34. These conduits, being arranged so that gas discharged by exhauster 63, may be utilized in several ways as desired.

The operation of the apparatus located at the production plant shown in Fig. 1 for providing a charge of subcooled liquid oxygen in the Vessel 48 will now be described. It will usually be preferable to reduce the liquid oxygen to the subcooled state when it issues from the production column III. When no liquid is to be transferred to the transport device I2, the flow of gas material is as follows: The exhauster 32 is set in operation and all valves are closed except as described. Valve 35 is open so that gas drawn from the top of vessel 22 by the exhauster through conduit 34 is discharged through conduit 20 into the suction chamber of injector I9, where it is entrained with gas material discharging from nozzle valve I8 into the column. The valve I8 is regulated so that the flow through conduit I1 of gas material coming from the high pressure chamber of the column is limited to the desired rate. Gas drawn into the column through conduit 20 is reliquefied by providing suflicient excess refrigerating effect in the column in ways known in the art. If it is desired not to reliquefy the gas discharged byy exhauster 32, it may be discharged to the gasometer by closing valve 35 and opening valve 31. Still another method for drawing off and disposing of the gas drawn from the top of vessel 22 is provided by the compressing unit I3, which when in operation draws gas through conduit 39, valve 4Il being opened, heats it to a temperature above the freezing point of the lubricant, and compresses it to the desired pressure for storage in the cylinders 46. By these means, the pressure in the vessel 22 is maintained at the relatively low value which is equivalent to the pressure of equilibrium at the low temperature desired in the liquid. For example, if, in the case of oxygen, it is desired that the temperature of the liquid shall be brought down to 77.5 K., the pressure would be 162 mm. of mercury absolute.

The liquid produced by the column passes out through conduit I6 into vessel 22, the rate of flow being regulated by valve 26, which acts as a throttling or expansion valve since the liquid in column I is generally undera higher pressure. On passing expansion valve 26, part of the liquid will ash into vapor, the balance being cooled to the desired temperature. The gas is drawn oil as described and the liquid falls to the lower part of vessel 22 from which it falls into the main vessel 2l, when valves 25 and 28 are open. When thus cooling liquid oxygenfrom a normal temperature of 90.15 K., the boiling point at one atmosphere, to 77.5 K., approximately 1/10 will be gasifled.- The gas so flashed oi will contain a greater percentage of the lower boiling point impurities, such as nitrogen, and thus the purity of they liquid will be increased. The present method of subcooling, therefore, has the desirable effect of increasing the purity of the product. The subcooled liquid in the storage tank II has the capacity to absorb a large quantity of the heat that leaks in through the insulation 23 before its temperature reaches 90 K. The subcooling may also be effected by operating the low pressure compartment of the column under a sub-atmospheric pressure so 4that the use of exhauster 32 would be unnecessary but the production apparatus would be correspondingly more bulky.

When it is desired to charge the transport device I2 with a quantity of liquid, the flexible conduits 54 and 66 are coupled between couplings 53 and 55 and 61 and 10, valves 25 and 28 closed, and exhauster 63 placed in operation. When valves 68 and 12 are opened, gas contained in the transport vessel 48 is exhausted and discharged through conduits 65, 66, 1I, 21 into the gas space of the vessel 2I until the pressure therein increases to the desired value, such that, when valves 51 and 52 are opened, a rapid i'low of liquid occurs out of vessel 2| into vessel 48 through the conduits 56, 54 and 5I. When the pressure in vessel 2I has been sufliciently increased, valve 12 is closed and valve 14 is opened to permit flow of gas to the other means for utilizing same, as previously described.

If the liquid in the storage vessel has become heated to a temperature higher than desired or if the liquid has been stored therein at approximately the temperature of its boiling point at one atmosphere pressure, the subcooling may be effected either during transfer of liquid into the vessel 48 or after it has been transferred. Cooling during transfer is effected by drawing gas out from the top of vessel 48 by causing the transfer as previously described, except that the valve 52 is manipulated to act as an expansion valve. The gas ilashed off when the liquid passes into vessel 48 is drawn out at the top of the vessel through conduit 62 by exhauster 63, which may work in series with the several gas utilizing means to which the gas is conducted by conduits 85, 88, 1| and 13. When the vessel 48 is filled with subcooled liquid, valves 52, 88, 51, 12 and 14 are closed and valves 28 and 25 opened so that gas under pressure in storage vessel 2| may pass to the gas utilizing devices through conduit 21, while the liquid collected in vessel 22 drops down to the main vessel 2|. The flexible conduits 54 and 88 are now disconnected to permit the transport device l2 to be driven off to a place where gas material is to be discharged at an elevated pressure. The subcooled liquid can be transported for a relatively long time before the heat leakage through the insulation will have raised its temperature to the boiling point temperature at one atmosphere. For example, in the case of liquid oxygen, if the heat leakage was such that when illled with oxygen at 90 K., the boiling point at one atmosphere, about 2 per cent. of the contents was evaporated in 24 hours, the same container when filled with liquid oxygen at 77.5 K. may be held for five days before the temperature is raised to 90 K. Thus, the liquid may be transported for long distances before it becomes necessary to start venting gas to the atmosphere for avoiding the development of super-atmospheric pressures. The stored refrigeration in the subcooled liquid is further utilized according to the present invention for reducing gas losses when the liquefied gas is transferred to vaporizing means and converted to gas of the desired high pressure for storage and consumption at a place of use, as will appear from the description of the remaining figures.

Referring to Fig. 2, there is shown the liquid transporting device |2 coupled to a portable conversion apparatus indicated generally by 15. The conversion apparatus is used for converting a desired portion of the liquefied gas into gas of the pressure desired for storage and use and is here shown as carried upon a vehicle 18 of the trailer type that is drawn by the motor vehicle 41, to which it is coupled by a draw bar means 11. The conversion device comprises a pressure resistant vessel or chamber 18 having a liquid connection 18 at the bottom and a gas connection 88 at the top. The lower connection 18 leads to and discharges liquid into a vaporizing coil 8| that is submerged in a bath of heating fluid held within a container 82. The vaporizing coil 8| terminates at its upper end in a coupling 83 provided for coupling the vaporizer to be in communication with a flexible portion 84 of a manifold conduit that leads vaporized gas into a number of high pressure storage cylinders 88. A pressure reducing valve 81 provides communication between the manifold 85 and a conduit 88 that conducts the gas reduced to a desired substantially constant pressure for use by consuming apparatus not shown. The other end portion of the manifold 85 is controlled by stop valve 88.

The liquid is forced into the chamber 18 by the action of an injector 88, the liquid being drawn into the injector chamber 88 through conduit 8|, which is placed in communication with the liquid in vessel 48 by being coupled at its external end to flexible conduit 54 at 82. The entrained gas material is forced into chamber 18 through a check valve 83 which communicates with connection 18. Gas containing the required heat energy is supplied to the nozzle of the injector 88 by conduit 84, which leads from connection 88 and is controlled by a valve 85. Insulation 88 surrounds both chamber 18 and the injector 88 to control the iniiow of heat to these parts. A bypass conduit 81 controlled by valve 88 and communicating with the gas passage between the combining tube of the injector 88 and the check valve 98, leads to and joins the vaporizing conduit 8|. Between this junction of conduits 81 and 8| and the junction of conduit 8| with connection 18, a control valve 88 is interposed in the conduit 8|. Leading from a point of the vaporizlng coils 8|, the conduit |88 pro- -vides communication between conduit 8| and both connection 88 and conduit 84. Conduit |88 is controlled by a valve |8| located between the vaporizing coils and the point where a conduit controlled by valve |82 branches therefrom to supply gas to the actuating nozzle of an ejector |83. Gas is supplied to the suction chamber of the ejector-through conduit |84 which is coupled to flexible conduit 88 by coupling |85. The ejector discharges through conduit |88, which is controlled by valve |81 and communicates with conduit 8| at a point close to coupling 88 which is here shown as located between coupling 83 and a stop valve |88, which controls the discharge from conduit 8|.

The operation of the apparatus when coupled together as shown in Fig. 2 for delivering a supply of gas is as follows: 'I'he exhauster 83 is started and valves 88, |81 and 88 opened so that gas may be drawn from the top of vessel 48 to be conducted through conduits 85, 88, |84, |88, 84 and 85 to the cylinders 88, which are assumed to have been exhausted of gas. Some gas will be held in chamber 18 at relatively high pressure, this gas having been left in the chamber from a previous operation. Such stored high pressure gas is utilized for operating the ejector |83 by opening valve |82 so as to assist the exhauster 83 by providing another stage of compression. This preliminary transfer of gas is stopped and valve 82 closed when a sufficient back pressure in cylinders 88 has developed and when the liquid in vessel 48 has been suilciently further cooled. But it is desirable to maintain a supply of gas under pressure in vessel 18 sufficiently higher than the pressure in receivers 88 for use in starting the injector 88; therefore,

the pressures of gas in vessel 18 and receivers 88 should not be allowed to equalize. The preliminary gas transfer serves usefully to cool the liquid in vessel 48 to remove heat that entered during the journey and to prepare it for the next steps of the method. The liquid must now be subjected to a higher preliminary pressure. This is accomplished by opening valve 88 for a sufficient time to permit back flow of gas from vessels 88 to provide the desired pressure of gas in the gas space above the liquid. This pressure would preferably be about two atmospheres absolute. The valves 88, 88, |82 and |81 are now closed. If the pressure is not high enough in vessel 48, further increase in pressure may be had by the use of the pressure building coil 58. To this end, valves 8| and 58 are opened permitting liquid to run into coil 58, and vaporize to flow into the gas space and increase the pressure therein without heating the main body of liquid in the vessel 48. The heat exchange between the expelling gas and the liquid is very slow, so that pressure will be maintained for a considerable period of time before equilibrium conditions are restored.

Liquid is next transferred. Accordingly, valves 52, 88 and |88 are opened. Valve 85 is at the 75 same time opened to supply gas from vessel 18- to the injector 90, which will draw liquid from vessel 48 through conduits 5|, 54, and 9i entraining it in the combining tube with condensation o! the gas. The mixture discharges through conduit 91 into vaporizer 8|, where it is converted to gas and conducted into the cylinders 86. As soon as the injector is operating properly Shortly after starting it, the valve 98 is closed and the liquid will be forcedthrough check valve 93 and ilow into chamber 18. Valve is now opened so that pressures in chamber 18 and vaporizing coils 8| will equalize. When the chamber 18 has filled with liquid, the valve 98 is again opened to divert the liquid into'the vaporizing coils 8|. The injector action is continued until it fails, which will occur at a pressure such that the Work of pumping requires as much or more gas than can be condensed by the liquid, upon which pressure being reached the valves 95 and 98 are closed and valve 99 is opened. The liquid in chamber 18 then flows by gravity through connection 19 into the vaporizing coils 8|, where it is heated so that the pressure iinally increases to a value which may be beyond the critical pressure, if desired. The exact value of this pressure is determined by the relative volumes of the chamber 18 and the combined volumes of the cylinders 86. When the pressures equalize and flow ceases, the valves are closed, conduit 84 uncoupled from coupling 83 and the transporting device I2 and converting device 15 driven away. It should be noted that true injector action is possible since the liquid oxygen has been pro'- vided with a temperature'that is sufl'iciently lower than its boiling point temperature at Athe pressure under which it is supplied to the injector suction chamber so that the gaseous oxygen supplied through the nozzle is condensed in the combining tube at the required velocity.

Referring to Fig. 3, the liquid transport device I2 is shown coupled to a form of portable converting device IIO which issmilar to the device 15 shown in Fig. 2, but differs in that two converting chambers are`provided and that liquid flows to the injector 90 under the influence of a gravity head in addition to a pressure head. The converting device I I0 mounted on the trailer 16, comprises two chambers |II and I|2 having liquid connections ||3 and |I4 each leading from their lowest portions to the discharge conduit 5 of the injector 90 and upper gas discharge connections ||6 and |I1, which provide communication between the chambers and II2 and the portion 94' that conducts gas to the actuating nozzle of the injector 90. The connections II3 and II4 are controlled by valves ||8 and II9, respectively, and the connections I|6 and |I1 are controlled by valves |20 and |2I. The portions of connections |I6 and |I1 between the chambers and the control valves |20 and |2| are placed in communication through a connecting conduit |23 which is provided with control valves |24 and |25 and communicates with the conduit |00 joining heating coils- 8| through connection |00' at the portion between the valves |24 and |25. Similarly, a conduit |26 joins the liquid connections I3 and ||4 in the portions between the valves I I8 and I I9 and the chambers III and |I2. Conduit |00 is extended to communicate with conduit 94 between stop valves 95 and 95. The conduit |26 is controlled by valves |21 and |28 between which it communicates with the inlet end of the heating conduit 8|. The vaporizing coils of the heating conduit 8| are submerged in the heating iluidheld in container |29. The extension 94' of conduit 94 leading to .the actuating nozzle of ejector |03 is controlled by the valve |02. In this form of the apparatus, liquid iiows into the injector chamber 90 through the extension of conduit 58 leading to coupling 60. This extension is here provided with a valve 60' and communicates with the inlet conduit 9| through flexible conduit |30, which is coupled between couplings 60 and 92. The conduit 9| is provided with a valve 9|'.

In this formlof apparatus, the one chamber is filled with liquid by injector action, while the contents of the other is being discharged to the vaporizing conduit 8|. 'After the liquid in vessel 48 has been subcooled to the desired degree, as described in connection with the apparatus shown in Fig. 2 and the gas pressure in vessels and 2 reduced to relatively low value, the conversion of liquid to gas is first started by opening the valves 59, 60', 9|',l ||8 and ||9, |21 and |28, |24 and |25, |2|, |02, 68 and 69. Liquid will then flow under the influence of gravity through conduits |30, 9|, I|5, II3 and |I4 and |26 to the vaporizing conduit 8|, where the liquid is vaporized, the gas flowing through conduits |00, |00', |23, |I1, 94', |04, 66, 65, the bypass controlled by valve 69 and conduit 62 into the gas space above the liquid in vessel 48. This action is continued until the pressure in vessel 48 has risen to the desired value. All valves except 59, 60', 9|', I I8 are now closed. When valves |25 and 95 and valves |20, |02, |01 and 89 are next opened, liquid is driven into chamber III by the energy of gas supplied through conduit 94 from chamber II2, the liquid Vflowing in through conduit I|3 and gas displaced from chamber ilowing to cylinders 86 through conduits II6, 94', |06, 84 and 85. When chamber I|| is suiiiciently charged, or when ow stops, the valves are changed as follows: Valves II8, |25 are closed and valves I 24, |21 and |08 are opened. The liquid charge of chamber ||I runs into vaporizer coils 8| by the action of gravity until the liquid is vaporized and the pressure in cylinders 86 further increased. The injector may now be operated to force liquid into chamber I2 and the vaporizing coil continuously until injector action ceases at a pressure under the critical pressure for the gas. For this step, the valves 95, II9, |24 are opened to start the injector operating, the liquid passing through conduits ||5 and ||4 to chamber I|2. As soon as the injector is operating steadily and the pressure in chamber I I2 has been raised to equal that in conduit 8| and cylinders 86, the valve |25 is opened. The chamber III, as well as chamber II2, is permitted to receive liquid by opening also valve I I8, and when lled, the valves |21 and |28 areopened just suiiiciently to permit liquid to pass into the vaporizing coil 8| at a rate equal to the rate of discharge from the injector 90. When the injector stops discharging liquid, the valves 95, II8 and |I9 are shut and valves |21 and |28 opened fully, so that the charge of liquid will run into the vaporizer to be vaporized and converted to gas having a higher pressure.

Another method of operating this form of the apparatus is to fill one chamber while the other discharges, for example, while chamber is discharging to the vaporizing coils with valves |24 and |21 open and valves I I8 and |20 closed, vessel ||2 is being illled, the valves I|9, 95, |02, |01 and I2| being open and the valves 95', |25, |08 and |28 being closed. When-chamber ||2 is illled, the valves are reversed, valves I|9, 2|,

|24 and |.21 being closed and valves ||8, |20, |25 and |28 being opened. This alternate action may be continued until the desired quantity of liquid has been converted into gas and stored in the cylinders 86 at relatively high pressure.

In Fig. 4 is shown the transport device I2 coupled to still another form of converting device |3|, which comprises an uninsulated chamber |32 of the heavy walled pressure resisting type having disposed within a thin Walled receptacle |33 so supported that the conduction of heat from the chamber |32 to the receptacle 33 is reduced to a small rate. The chamber |32 is provided at its upper portion with the gas connection 80 and at the lower portion with a liquid conduit |34 that is in communication with the liquid space of the receptacle |33 at its upper end and with the discharge chamber of a check valve |35 at its lower end. The check valve |35 prevents back flow of fluids into the discharge chamber |36 of the injector |31. 'I'he conduit 94 controlledby valve 95 leads from connection 80 to supply the motivating iiuid to the injector nozzle. Liquid is supplied to the injector by a rotary pump |38 through its discharge conduit controlled by valve |39. The pump |38 receives liquid through its inlet conduit, which is controlled by valve |40 and terminates externally with coupling |4|, which is coupled to conduit |30. The pump is directly driven by electric motor |42 through the extended'shaft |43. 'I'he vaporizing conduit 8| communicates with the liquid conduit |34 and is provided with the valve 99 located close to the junction. Communication between chamber |38 and coils 8| is provided through conduit |44 controlled by valve |45. To even the rate of supply of liquid to the injector, a surge chamber |46 communicating at its lower end with the injector chamber |31 and at its upper portion with a conduit |41 controlled by valve |48, is provided. The conduit |41 communicates at its other end with the conduit 44 between the valve |45 and conduit 8|. Only the pump, injector, surge chamber |46 and the liquid conducting conduits need be protected from the heat of the atmosphere by insulation shown at |49, as the space between the walls of the chamber |32 and receptacle |33 provides sufllcient resistance to the ilow of heat into the liquid that enters receptacle |33. A conduit |50 communicates with flexible conduit 66, being joined thereto by coupling |5|, and with conduit 8| between valve |08 and coupling 83. It is controlled by valve |01. A vent connection |52 controlled by valve |53 communicates with conduit between valve |0| and connection 80 and is used for venting gasto the atmosphere when desired.

When this form of apparatus is coupled as shown, the operation of servicing the cylinders 86 with gas of the desired high pressure is started by opening valves 59, 60', |40, |39, |48, |08 and 89 and starting the pump |38 into operation. 'I'he liquid is then drawn from vessel 48 through conduit |30 into the pump and forced thereby through the injector chamber |31 and surge chamber |46 and through conduits |41, |44, 8| and 85 into the cylinders 86, the liquid being converted into gas during its passage through the coils of conduit 8|. When the chambers |31 and |46 have been cooled to the desired temperature, the valve |45 is opened and valve |48 closed, the liquid then passing through the injector chamber |31 and combining tube |36 to conduit |44. This action may be continued until a pressure is reached that approaches the maximum against which the pump |38 can discharge. The valve 95 is then opened tov start the injector and gas under pressure, which has'been stored in the chamber |32, iiows to the injector nozzle to actuate same and force the combined iluids from the combining tube |36 through conduit |44, while.

the pump continues to supply liquid to the injector chamber |31. 'Ihe pressure in chamber |32 will soon be reduced to equal that in the coils 8|. When this occurs, valve |0| is opened so that warm gas for actuating the injector may flow from the coils 8|. 'I'he valve |45 is next closed until the basket |33 in chamber |32 is rllled with liquid, after which it is opened sui'llciently to pass all the liquid pumped to the coils 8|. The operation continues until the pressure becomes too high for further operation of the injector when valves |45 and 95 are closed, the pump |38 shut down and valve 93 opened. The

liquid in the basket |33 wil then flow under hydraulic head into the coils 8| to be converted into gas of 'still higher pressure. If it should be desired to increase the pressure of gas in the cylinders 86 to a still higher value, the chamber |32 may be alternately lled with liquid and discharged to the vaporizer several more times. When this is to be done, valves |45, 99 and |0| are closed and the pressure in chamber 32 reduced to an expedient value lower than the critical pressure of the gas by releasing some gas through conduit |52. The pump is started and valve 95 opened. When the basket |33 is lled, valve 95 is closed and valves 99 and |0| opened to allow the charge to flow into coils 8| and be vaporized.

' Referring to Fig. 5, the liquid transporting device I2 is shown in position for servicing a vaporizer of the Warm converter type shown generally at 2 l0 and so located with reference to the device I2 that liquid may run into it from the vessel 48 under the iniiuence of gravity. The warm converter comprises a heavy walled pressure vessel having a gas-tight cover and a thin walled inner receptacle or basket 2| Three conduits lead through the cover of the converter; the rst conduit 2|2 connecting at its outer end with conduit |30, is utilized lfor conducting liquid into the basket of the converter, and is controlled by a valve 2 I3. A second conduit 2|4 is provided for discharging gas. This latter conduit leads to the atmosphere from a point in the converter below the row of holes in the basket, which is approximately the level to which it is desired to ll the' basket, and is provided with a branch 2|5 connecting with a iiexible portion 2|6. Stop valves 2|1 and 2| 8 are provided in the conduit 2|4 on either side of the branch A conduit 2| 9, communicating with the gas space above the liquid in vessel 48 and externally with conduit 2|6 is provided for discharging gas from the converter into vessel 48 above the liquid therein. Conduit 2|9 is provided with a control valve, 220. 'Ihe third conduit 22| passing through the cover is the usual gas discharge conduit but here it conimunicates at its external end with the ilexible conduit 66. It is also provided with two stop valves 222 and 223. Between valve 222 and the converter, there is provided a branch 224 for conducting gas to a safety release device 225 that releases gas if the pressure in conduit 22| should exceed a predetermined safe working value. 'I'he manifold conduit 85' branches from conduit 22| from a point Vbetween valves 222 and 223 and conducts gas to the cylinders 86.

The form of gasifying plant shown in Fig.

is serviced and operated as follows: It will be assumed that the gas remaining in the converter has been reduced to the lowest pressure reached in conduit 88. Valve 222 is closed yand the exhauster 63 is placed in operation, then valves 68 and 223 are opened so that gas may be drawn fromvessel 48 and discharged to the cylinders 86. Valves 2I1 and 229 are opened gradually so that gas will pass from the converter into vessel 48 and be drawn out again by the exhauster, The exhauster is operated until its upper discharge pressure limit is reached, after which valve 2I3 and 59 are opened and since the pressures in the converter and vessel become equalized ata relatively low value, liquid will flow under the influence of gravity from vessel 48 into the converter. The pressure level reached, however, will generally be greater than the pressure of equilibrium with the liquid. Since the liquid entering is in the subcooled condition, the heat stored in the metal of the basket will be absorbed by the liquid without excessively increasing the pressure, and, in addition, the mixing of the liquid with the gas in the converter will cause some heat transfer between gas and liquid, with the result that some gas will condense. In the event that the pressure in the converter was or becomes too high to be safely held in vessel 48, gas is released by opening valve 2 I8 for a desired period. The quantity so released, however, will be far less than the amount usually released to the atmosphere by former methods of filling warm converters. The exhauster is stopped and valves 68 and 223 are closed. When the basket is filled, as shown by the discharge of liquid`when opening valve 2I8, which indicates that the liquid level has reached the depending end of conduit 2|4, valves 59, 2I3, 2I1 and 220 are closed and valve 222 is opened. The transport device is disconnected and driven away, while gasification of the liquid in the converter proceeds as heat enters through the wall from the heating fluid in contact with the converter.

In Fig. 6 is shown the transport device I2 coupled to a portable pumping and vaporizing apparatus, shown generally at 230, which is arranged for forcing fluid into a vaporizer for conversion into gas. The pumping and vaporizing apparatus is carried by a trailer 23I, which is drawn by the transport vehicle I2 through the medium of a draw bar coupling 232. The pumping means comprises a reciprocating pump having a chamber 233 designed to withstand a relatively high internal pressure and provided with inlet ports 233' which are uncovered by the lower end of a piston or `plunger 234 Working in the pump chamber. The discharge passage, controlled by non-return valve 235, communicates with the chamber 233 at its lower portion and with a vaporizing coil 236 disposed within heating jacket 231. 'I'he pump chamber 233 is disposed within a. heat insulated container 238 provided with liquid inlet and gas outlet connections communicating with conduits I 30 and 2I6, respectively, and controlled by stop valves 239 and 240. The piston 234 is elongated to increase the resistance to conduction of heat through it to the pump chamber and to this end passes through a relatively long packing gland 24 I. The piston 234 is reciprocated by the crank disk 242 through the agency of a connecting rod 243; the crank being actuated by a suitable prime mover, for example, by an electric motor 244 which preferably turns it at a relatively slow speed.

The vaporizing conduit 236 communicates at its external end with conduit 84 and is controlled by a valve 245 located in it close to the coupling. A conduit 246 branches from conduit 23,8 at a point between its coiled portion and valve 245 and is provided with a coiled` portion inthe heating fluid before it connects with conduit 66. It is controlled by a valve 241.

When the apparatus is coupled together as shown in Fig. 6, the liquid in vessel 48 may first be further subcooled by placing exhauster 63 in operation and opening valves 68, 241, 245 and 88, the gas drawn out of vessel 48 being forced over into the cylinders 86, which have previously been exhausted to a relatively low pressure. Such gas is warmed to the desired temperature on passing through the coil portion of conduit 246. When the desired cooling has been attained, or when the back pressure of gas in the cylinders 86 grows .too high for the exhauster to act against, the exhauster is stopped, valve 69 is opened to allow suilicient back flow of gas into vessel 48 to create therein a desired temporary pressure, when valves 69, 241 and 68 are closed. Then valves 59, 239, 240 and 220 are opened, whereupon liquid will ow under the influence of gravity into the container 238, the gas displaced therefrom passing over to the vessel 48 through the conduits 2I6, 2I9. The connection controlled by valve 249 is so positioned that the liquid will rise in container 238 just sufiiciently to cover the inlet ports 233' to a desired depth and to trap vapor in the space above this level. The motor 244 is energized by closing the electrical circuit between it and a suitable source of current, such as may be available at the location, or the storage battery of the transport vehicle I2. 'Ihe upstroke of the piston 234 uncovers the inlet ports 233 so that liquid flows into the pump chamber by gravity, displacing gas of liquid out through the check valve 235 into the coils 236, where the liquid is heated and converted into gas of the desired pressure. This gas flows through conduit 84 and manifold 85 into the cylinders 86, where it is stored for supplying the consuming apparatus upon demand.

As the liquid entering the pump chamber is subcooled, the tendency to ash into vapor in the pump exhibited by liquids at their boiling points is not present. Therefore, the pump operates with greater eiciency. liquid further has great power to cool the metal of the pumping device without excessive vaporization when pumping is first started. Gas vaporized in the vpump passes over to the vessel 48, where it serves to create and maintain a nonequilibriumA pressure above the liquid, whereby the tendency for flashing and the restriction of the flow into the pump are minimized. Gas remaining in the vessel 48 will gra'dually be condensed through heat exchange with the subcooled liquid that remains after discharging the desired quantity. .When the cylinders 86 contain the desired quantity of gas, the liquid controlling valve 59 is iirst closed and pumping is continued for a short time to remove as much of the liquid from container 238 as possible; then the pump is stopped and the other valves closed.

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

The sub-cooled therefrom, and the downstroke drives the charge Having described my invention. what I claim as new and desire to secure by Letters Patent is:

1. Apparatus for dispensing gas material that has a boiling point temperature at normal atmospheric pressure below 273 K. which comprises the combination with a source for supplying liqueiled gas at a relatively low pressure, oi a thermally insulated container for receiving and holding a charge of liquefied gas at a relatively high pressure, conduit means for effecting a transfer of the charge into said container, means for cooling by expansion the charge being transferred, independent means for cooling the charge by withdrawing and conserving vapors generated within said container, and insulated receiving means connected for withdrawing the charge when cooled.

2. Apparatus for dispensing oxygen for industrial consumption which comprises the combination with a transportable container for liquid oxygen, of a receiving device associated with said container and adapted to receive gasV material therefrom and provided with passages for dividing the gas material received into two portions, a vessel communicating with one of said passages for receiving and storing one of said portions, a vaporizing means connected with the other of said passages, and means for utilizing the energy of gas material at high pressure to accelerate the passage of gas material into said vaporizlng means.

3. Apparatus for dispensing oxygen for industrial consumption which comprises the combination with a transportable container for liquid oxygen, of a receiving device associated with said container and adapted to receive gas material therefrom and provided with passages for dividing the received material into two portions, a vessel for temporarily receiving and storing one of said portions communicating with one of said passages, vaporizing means communicating with the other passage, a connection for delivering gas material directly from said vessel to said Vaporizing means, and means associated with said device for withdrawing gas material in the gas phase and utilizing it at a relatively high pressure for assisting the transfer of gas material.

4. Apparatus for dispensing gas material that has a boiling point temperature at normal atmospheric pressure below 273 K., which comprises, in combination, a. transportable container for holding a charge of liquefied gas, means for receiving the gas material from said container, and conduit means for conveying the gas material from said container into said receiving means and arranged to divide the same into two portions, said receiving means being heat insulated and including storage means communicating with raid conduit means for receiving and temporarily storing one of said portions and vaporizing means connected to said conduit means for receiving and gasifying the other portion.

5. Apparatus for dispensing gas material which has a boiling point temperature at normal atmospheric pressure below 273 K., which comprises, in combination, a transportable container for holding a charge of liqueiied gas, means for receiving the gas material from said container, and conduit means for conveying the gas material from said container into said receiving means and arranged to divide the same into two portions; said receiving means being heat insulated and provided with a vessel communicating with said conduit means for receiving and temporarily storing one of said portions, a vaporizing coil -communicating with said conduit means for receiving the other portion, and means for warming said vaporizing coil.

6. In a method of dispensing gas material that has a boiling point at normal atmospheric pressure below 273 K., the steps which comprise storing and sub-cooling a body of liquefied gas. introducing at least a portion oi' said body in a condition subcooled to a temperature below the boiling point temperature which corresponds to a pressure at which it is subsequently to be handled into the receiving chamber of a thermally insulated pump, pumping said received portion by forcing the same from. said pump chamber against a relatively high head of pressure, and withdrawing and conserving any vapors that ash from said received portion while being pumped.

7. In a method of dispensing oxygen for industrial purposes, the steps which comprise storing-and subcooling a body of liquid oxygen, introducing at least a portion of the liquid oxygen so stored when subcooled to a temperature materially less than K. into the receiving chamvber of a thermally insulated pump, pumping said received portion of liquid oxygen by means of energy supplied from. an external source to force said received portion from said pump chamber against a relatively high head of pressure, and during the pumping step withdrawing and conserving any gaseous oxygen that may flash from the portion while in transit through the pump.

8. Apparatus for dispensing liquefied gas material that has a boiling point temperature at normal atmospheric pressure below 273 K. for industrial consumption which comprises the com.- bination with a source for supplying such liqueiied gas at relatively low pressure, of a closable container that is protected by insulation and has a connection for receiving a charge of liqueiied gas transferred from said source at said low pressure, said container having a wall of a strength adapted to resist a pressure of a relatively high value which may be attained when said container is closed, and cooling means associated with said container for lowering the temperature of the charge therein to a value materially below the boiling point at the pressure at which said charge is transferred, said cooling means consisting oi a pair of independent devices, one of which comf prises a means for cooling by expansion the liquid transferred and the other a mechanism for cooling the liquid transferred by evaporation.

9. Apparatus for dispensing oxygen for industrial consumption which comprises the combination with a source for supplying liquid oxygen at a relatively low pressure, of a closable container that is protected by thermal insulation and has a connection for receiving a charge of liquid oxygen transferred from said source at said relatively low pressure, a cooling device comprising an expansion valve in said connection for lowering the temperature of the charge transferred, and an additional cooling device connected to said container and including a suction pump adapted to withdraw gaseous oxygen from the upper part of said container to eifect cooling of the charge in the container by evaporation and assist in transferring liquid oxygen thereto.

l0. Apparatus for dispensing oxygen for industrial consumption which comprises the combination with a closable transportable container for liquid oxygen, of a device for receiving gas material from said container and having passages for dividing the same into a plurality of portions, a vessel communicating with one of said passages for receiving and storing temporarily one of said portions, a vaporizing means communicating with another of said passages, a connection for passing the stored material from said vessel to said vaporizing means, gas phase withdrawal means having branches leading from said container and vessel, one branch including a pump for effecting positive removal oi' gas material in the gas phase from said container, and a receiving system provided with mechanism for detachably connecting it to said gas phase withdrawal means.

11. Apparatus for dispensing oxygen for industrial consumption which comprises the combination with a closable transportable container for liquid oxygen, of a device for receiving gas material from said container and provided with passages for dividing the same into two portions, ay vessel communicating with one oi said passages for receiving and temporarily storing one of said portions, a vaporizing device communicating with the other passage, a communication for passing gas material directly from said vessel to said vaporizing device, gas phase withdrawal means having branches leading from said container and said vessel, one branch hav-` ing a compressor for elevating the gas withdrawn to a relatively high pressure, a pair of injectors associated with the other branch for assisting the passage of gas material, one of said injectors being disposed at an entrance to said vessel, and a receiving system arranged to be connected jointly to said compressor branch and said other injector branch.

12. lThe method of handling normally gaseous material to provide for the delivery o! a predetermined quantity in bulk form from a production plant to a consuming installation, which method comprises segregating. in a container protected by insulation andmounted on a transportable vehicle, a charge of said material in the liquid phase suilicient in quantity not only to offset evaporation losses occasioned by the handling of the charge at the production plant but also to insure the delivery of said predetermined quantity, and subcooling said charge of liquid to a temperature suiliciently low to oiiset the leakage of heat into the container through the insulation and to insure that said charge will be at a temperature below its boiling temperature at the existing pressure when delivered.

13. The method of handling oxygen for industrial use in consuming systems which comprises producing liquid oxygen at a production plant at a pressure of a value not greatly different from atmospheric, segregating a charge of the liquid oxygen so produced in a closable container that is protected by insulation, said charge being in an amount such as to leave a space of predetermined volume for'vapor above the liquid in the container, subcooling the liquid oxygen introduced within said container to a temperature below a value taken suiilciently low to oiset any heat leakage into the container at a known rate during a predetermined period such as that required for transportation, said subcooling being practiced by expanding a portion of the liquid and by withdrawing gaseous oxygen from the space in the container, and thereafter discharging at least a portion oi' the liquid oxygen within the container while in said subcooled condition to a consuming system.

14. The method of handling oxygen for industrial use in consuming systems which comprises charging a closable container that is protected by insulation with a body of liquid oxygen, subcooling said body to a temperature which is suiiiciently below 90 K. to permit heat leakage at a known rate for a predetermined period without exceeding 90 K.. withdrawing gaseous oxygen from said container to effect further subcooling of the charge therein, compressing said withdrawn gaseous oxygen and conserving the same by storage in a receiver at relatively high pressure, transferring a portion of said subcooled charge to receiving means containing gaseous oxygen under a pressure less than said relatively high pressure, withdrawing and employing the gas under pressure from said receiving device for assisting the transfer of said portion of subcooled liquid, discontinuing said transfer and vaporizing said transferred portion of liquid to generate a pressure in excess of said relatively high pressure for storage in said receiving means.

15. The method of handling gas material which in the liquid phase has a boiling point temperature at normal atmospheric pressure below 273 K., which method comprises charging a closable transport container that is protected by insulation with a body of liqueed gas which has been subcooled to a temperature materially below a boiling point temperature correspond'- ing to a pressure of predetermined permissible value attainable during a period when the Vliquis is being transported, transporting said container while closed to the atmosphere during said period and with the pressure therein less than said predetermined value, building a discharge head of pressure in a portion delivered from said container by imparting kinetic energy thereto, and discharging said portion to receiving means when the discharge head is in excess of the pressure obtaining in said receiving means.

16. The method o! handling gas material which in the liquid phase has a boiling point temperature at normal atmospheric pressure below 273 K., which method comprises charging a closable transport container that is protected by insulation with a body of liqueiied gas which has been subcooled to a temperature materially below a boiling point temperature corresponding to a pressure of a predetermined permissible value attainable during a period when the liquid is being transported, transporting said container while closed to the atmosphere during said period and with the pressure therein less than said predetermined value, building a discharge head of pressure in a portion delivered from said container by imparting heat thereto to vaporize the same, and discharging said portion to receiving means when the discharge head is in excess of the pressure obtaining in said receiving means.

17. The method of handling gas material which in the liquid phase has a boiling point temperature at normal atmospheric pressure below 273 K., which method comprises charging aclosable transport container that is protected by insulation with a body of liqueiied gas which has been subcooled to a temperature materially below a boiling point temperature corresponding to a predetermined permissible value of pressure attainable during a period when the liquid is being transported, transporting said container while closed to the atmosphere during said period and with the pressure therein less than said predetermined value, building a discharge head of pressure in a portion delivered from said container by imparting thereto both kinetic energy and heat energy, and discharging said portion to receiving means when said discharge head is in excess of the pressure obtaining in said receiving means.

18. The method of handling oxygen for industrial use in a consuming system, which method comprises charging a closable transport container that is protected by insulation with a body of liquid oxygen at a pressure below atmospheric and subcooled to a temperature suiiiciently below 90 K. to offset heat leakage at a known rate for a predetermined period without attaining 90 K., transporting said container while closed for discharge at a consuming system and with the pressure therein higher than that of the charging pressure but not greatly diierent from atmospheric, then building a head of pressure in the container, discharging liquid oxygen under said head to the system, vaporizing a portion of the discharged liquid oxygen, increasing the pressure of said vaporized portion to a head of desired value by imparting energy in kinetic form to the vapor generated from a supply of gas at a relatively high pressure, thereafter heating a remaining portion in a vaporizer to provide additional gaseous oxygen at a pressure of desired head value, and then delivering all of the gaseous oxygen so provided to receiving means when the pressure head is in excess of the pressure obtaining in said consuming system.

WILLIAM F. lidESmGER.

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