US2362984A - Method and apparatus for dispensing and conserving gas material - Google Patents

Description

Nov. 21, 1944. G. J. BOSHKOFF METHOD AND APPARATUS FOR DISPENSING AND CONSERVING GAS MATERIALS 2 Sheets-sheaf 1 Filed Sept. 5, 1941 & INVENT Wam flail/7522? 1944- G. J. BOSHKOFF 3 METHOD AND APPARATUS FOR DISPENSING AND CONSERVING GAS MATERIALS Filed Sept. 5, @341 2 Sheets-Sheet 2 IN 'NTOR 7%, M fli TTORNEYS Patented Nov. 21, 1944 METHOD AND APPARATUS FOR DISPENSING AND CDNSERVING GAS MATERIAL George John Boshkofi, Snyder, N. Y assignor to The Linda Air Products Company, New York,

Application September 5, 1941, Serial No. 409,626

12 Claims.

This invention relates to a method and apparatus for dispensing and conserving gas material, and particularly to a method and apparatus for dispensing and conserving both gas and liquid phases of a material-which has a boiling point temperature ,at atmospheric pressure materially less than 273 K., such as liquid oxygen.

The invention has for its object generally the provision of a novel cycle of procedural steps for dispensing and conserving gas material of the kind indicated, together with suitable apparatus for carrying out such steps.

More specifically, the object of the invention is to provide a cycle of procedural steps for a liquid oxygen dispensing system of the type commonly installed at consuming installations and having means'for storing and delivering liquid to be vaporized whereby relatively large quantiparatus of the character indicated with storage means for the liquefied gas arranged to have an operating essure therein with a relatively low upper limit, and accordingly employs mechanical means for efiecting withdrawals of both gas and liquid phases.

Another object is to provide a system of apparatusoi the character indicated with a storage container having an internal liquid containing vessel of relatively light construction and associated means for withdrawing both gas and liquid phases automatically in response to predetermined operating conditions.

Another object is to provide an improved gas phase pumping means which use pistons for withdrawing gas from storage containers in systems. of the character indicated, with an im proved arrangement and construction avoiding the necessity of introducing lubricant for the piston into the pumping chamber.

Still another object is to provide an improved gaspump and compressor adapted for pumping and/or compressing gaseous oxygen without daner, by the employment of piston rings of a selflubricating character, thereby dispensing with hydrocarbons or other externally introduced lubricants.

Other objects of the invention will in part-be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of oneor more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations 01' elements andarrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding oi the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic view disclosing aliquefied gas dispensing system arranged in accordance with the invention;

Fig. 2 is a fragmentary sectional view, showing a gas compressor of the type shown in Fig. 1, equipped with self-lubricating piston rings in accordance with the invention; and

Fig. 3 is a diagrammatic view showing an arrangement of electric wiring for effecting the automatic control of the gas and liquid phase withdrawal means employed in the system of Fig. 1.

In installations arranged to receive a liquefled gas and vaporize it for industrial use, a liquid receiving or storing container is a common component, and where liquid vaporizing devices are employed, the liquid holding vessel 01' the storage container is required to be of a strength suillcient to withstand the pressures generated in the vaporizer. Since the storage container may have a relatively large size, it is not infrequently desirable that the liquid holding vessel thereof should be of light construction in order to reduce installation costs. This may be achieved by the cycle of steps practiced in accordance with the invention. Withdrawal of liquid phase from the storage container to be vaporized and meetv the service demands is here practiced in a manner which avoids pressure upon the container. An arrangement of this character is shown in the U; S. patent tofMesinger,

no, the withdrawal being stopped as soon as a predetermined low value is reached. A mechanical gas compressor is a suitable means for effecting' such withdrawal, and it is advantageous to provide an electric motor for driving the gas compressor, which is arranged to be controlled automatically ,by pressure switches suitably lo- I cated in the system.

elevated to a suitable high pressure and fed to The withdrawn gas phase the service pipeline to augment the material supplied to meet a service demand. In this way,

it is seen that the gas phase which was generated in the container by heat leak is conserved.

1 When 'the gasphase is thus supplied to the load, it is not desirable to discharg compressed gas intothe service pipeline when a predetermined high pressure is attained therein. In the event sources the insulation for the connection I: being shown generally at l2. The container is adapted to be filled from transport containers which bring charges in suitable amount from production plants and transfer the same to the inner or liquid holding vessel of the container 10. To effect such transfer of liquid quickly from the transport container, 9. transfer pump is advantageously introduced in the filling line and is here shown at 45, having an inlet i3 adapted forv connection to the transport.- container and an outlet or delivery connection l4 having a branch l4 communicating with theliquid'space of the container. A second branch i4" is also provided communicating with the gas space, there being additionallyn gas phase connection i6 adapted for connection with the gas space of the transport container to effect priming of the pump l5. Suchpump is driven from any convenient source of mechanical power, as hereinafter more fully described.

discharge connections 2i and 2|, respectively. Communicating with each of the discharge connections of the pumps is a priming connection 21-21 which is automatically controlled by a valve as shown at 28-48, these connections having a common portipn 29 leading into the container l0.

,To withdraw and conserve the gas Phase generated in container ID in accordance with the invention, the gas phase connection l2 has introduced therein a mechanical compressor, shown generally at 30, which is indicated as driven by an electric motor A, automatically controlled as hereinafter described. The compressor discharges into a pipeline branch or connection 3!, which preferably includes a check valve as shown at 3|, gas receivers 32 being connected to such connection if desired. For connection 3| the discharge passes into the pipeline 24. The gas compressor'is provided with a by-pass 34 thereabout leading from connection l2 into connection 35 and having therein a valve 33 which is preferably automatically controlled and is normally open when the compressor is not running.

Different types of compressors may be employed in the gas phase withdrawal connection, but a compressor of the type shown in Fig. 2 is preferred utilizing self-lubricating piston rings, which avoids the presence of explosive organic substances in contact with the oxygen under pressure. Here, 35 denotes a piston reciprocating in a cylinder 36, which is provided with a cooling system and to this end includes a jacket 31 (see Fig. 2), through which water, or a suitable anti-freeze solution, may be circulated. The piston thus formed is provided as noted with one or more self-lubricating piston rings 38, which are also resistant to combustion with oxygen gas under pressure. A bonded graphite is an example of a suitable material of this character. Such type of pump and lubricating means is advantageous in that it permits low temperatures to be employed and reduced power consumption, there being no liquid lubricant present to freeze. The jacket 31 is connected to a radiator 39 (Fig. 1) which may be air cooled by suitable means, for example, by means of a fan, as shown at 40, the fan being driven by an electric motor, here denoted B, and preferably ably introduced in duplicate, in order that one may serve as a spare. An arrangement of this character is shown in Fig. 1, where 20 and 20 show turbine type pipeline pumps having inlet connections I!) aand I9 respectively, which may be valve controlled and are branches of the connection I I. These pumps have outlet connections it and 2| discharging into a'common connection 22 leading to a vaporizing coil 23 that discharges into a pipeline 24. Pipeline 24 preferably has a regulating device 25 disposed therein for regulating the service pressure; such de-' vice preferably having a manifold with regulators in parallel branches, one of which may serve as a spare. If desired, as under "heavy demand, discharge may be effected simultaneously through both regulator branches andthe arrangement provides, therefore, for a wide variation in the delivery rate of pipeline 24 with relatively small capacity inexpensive regulators rather than requiring large capacity regulators.

Check valves 26 and 26' are also inserted in the arranged to be automatically controlled simultaneously with the motor A, as hereinafter more fully explained. The circulation of the-cooling medium through the radiator 39 may be effected in any convenient manner, for example, by means of a thermal siphon or pump. Where the latter is used, the pump may be driven from the motor B (the showing of which is omitted from the drawings in the interests of clearness of illustration, since its use is not essential to the present invention).

In the present invention, the pumps 20 and 20' are advantageously driven by electric motors awtomatically controlled in association with motors A and B. The pump 15 is likewise preferably driven by an electric motor which may, if de-: sired, also be automatically controlled. A suitable electrical system or network for effecting the controls is shown in Fig. 3. Here, a suitable source of electric energy is indicated symbolically by a pair of bus-bars 50, such source being either A. C. or .D. C. as convenience may indicate. Conductors 5l,.which serve as feeders or line leads for the motors employed in the present invention, are run from the busses 50, power for the several motors being tapped therefrom.

Tapping conductors for the motors A and B are shown at 62, the motors A and B being indicated as connected in parallel thereto. The motors for driving the pumps and 20' are shown respectively at C and C. These motors each having tapping conductors 63 and 53, which conductors supply the motors ,C and C' with electric energy in'parallel to one another and in parallel with the set of motors A and B. It may be here noted that in accordance with the general principles of the system the motors A and B operate the component parts of the gas compressor and functionautomatically to maintain the pressure in the liquid storage container between certain predetermined limits, subject to a further control pre-- ductors, which connect motor D so as to be supplied with electric energy in parallel with the other motors, have therein a suitable starting and controlling device 55 which may be manually actuated.

A pair of conductors denoted 6| and 6i are connected to the busses 56 in order to. supply current to the automatic controlling devices here employed. A relay coil 62 is connected across the conductors 6| and 6| for actuating the motor controlling means, here symbolized as double pole switch 626 in the conductors 52, which supply electric energy to energize motors A and B.

In series with the coil 62 are connected a pair of pressure actuated make-and-break devices 62l and 622 which are themselves in series. suitable devices of the character indicated, known to the prior art, may be employed for this purpose; the devices being here symbolized by a pair of mercury type switches in series in, the circuit, each switch being actuated by a Bourdon type pressure responsive element. In parallel with the coil 62'but in series with the devices 62l and 622 is another coil 623 serving as a relay coil for actuating a switch 336 which controls a circuit 33! connected across conductors 6| and 6| and has an actuating coil 332 in series for operating the by-passing valve 33 of the gas compressor 30. Here the arrangement is such that when coils 62 and 623 are de-energized, switch 336 is closed, so-that coil 332 is energized and the valve 33 open.

Two other coils 63' and '63- are connected across conductors 6| and 6| in circuits in parallel to each other for actuating the control devices in tapping conductors 53 and 53'; such devices being again symbolized by double pole switches 63!! and 63! respectively. These control circuits advantageously have a common portion 632 connected to one side of the main control circuit, here shown as conductor M; the portion 632 having in series with it a pressure actuated switch 633 depicted as of the same type as those at 621 and 622, althoughany suitable device may here be employed. Common portion 632 of the control circuits has two branches leading respectively to diametrically opposite poles of a double pole, double throw switch 634 which has a pair of manually actuated knife-blade switches at 635 for selecting one or the other of the diametrically opposite pair of poles .and thereby select one or the other oi coils 63 and 63' to be energized. In series with each of these coils and in the branches leading from switch 634 are disposed motor starting and stopping switches, here depicted as push-button switches, and denoted collectively at 636 and 636' for controlling respectively the coils 63 and 63'- In parallel with each of the coils 63 and 63' but inserieswith device 633 and switch 634 are connected coils 623 and 628' arranged to control directly, or through a relay if desired, the priming valves 28 and 23' (Fig. 1) of the pumps operated respectively by motors C and C, each of thecircuits that energize coils 628 and 623' being arranged to be opened by pressure as soon as the pumps are primed. To this end, each of these circuits has in series with it pressure controlled make-andbreak devices, here symbolized by rectangles 638 and 638'. Such device may again be any suitable device known to the prior art. The pressures which actuate these ,devices are thosere' spectively in the priming connections 21 and 21', as shown in Fig. l.

The pressure controlling device 633', which automatically starts and stops the pipeline pump,

' that of 175 psi gauge, and to stop the same Any when the pressure has attained a predetermined pressor whenever a predetermined low value, for

example, 15 psi gauge, is reached. The device 622, which is normally closed, is set to open the controlling circuit of motor A whenever the pressure in pipeline branch 3| exceeds a predetermined value, for example, 250 psi gauge.

I In operation, it is seen that the method of the present invention is carried out by apparatus arranged as above described, since liquid transferred by pump l5 to the container ill from any transport container may be stored therein with relatively little evaporation of liquid taking place. The container is, of course, operated at all times closed to the atmosphere. The pressure therein is, however, maintained between definite limits, those given above by way'of example being 15 and 25 psi gauge.

When a demand for gas material is made upon the pipeline 24, a pressure drop ensues therein, and the device at 633 starts the pipeline'pump, for example, pump 26, by energizing its actuating motor C. The pump when started in the first instance operates against no pressure head forced past the check valve 26 into the heating coii.23, where the liquid is vaporized and forced into the pipeline. By the arrangement shown in-Fig. 1, it is seen that the liquid is automatically forced through the heating coil 23 regardless of pressure in the container I0.

When evaporation builds pressure in the container' III to a predetermined value, that described above by way of example being 25 lbs., then the control device -62| is closed, and assuming the control device 622 is also closed, the circuit through '52 is completed and motors A and B are started and the compressor 30 begins to operate. Simultaneously with the closing of the control device MI and the starting of compressor 30 the coil 6231s energized which opens switch 330 permitting normally open by-pass valve 33 to close. With this form of arrangement the capacity of'line 3| from the compressor to the check valve 3| will be properly proportioned so that the compressor can be brought to operating speed before the pressure increase in this portion of the line is of such value as to impose undue starting loads on the compressor. The compressor operates to withdraw from the container ||l gas resulting from vaporization and to pass it into the receiver 32, or to the pipeline branch 3|, as the case may be, unless or until the pressure therein has attained a predetermined value, for example, 250 psi gauge. When this predetermined high pressure is reached in lin 3|, control device 622 is opened and motors A and B stopped and the 'electro-magnet 332 reenergized, hence opening the by-pass valve 33. It will be understood, of course, that even though the pressure in container l builds up sufliciently to close control device 62| the compressor will not start if the pressure in line 3| is already sufficiently high to open the control device 622 and operation of the compressor will be deferred until the pressure in line 3| drops below the predetermined value. A relief valve insures against pressure building up too high in container H3 in the interim. The simultaneous operation of the motor B with the motor A insures adequate cooling of the compressor during the step of withdrawing gas phase from the container I0. Assuming the control device 622 remains closed, as soon as a predetermined low value is reached by the gas phase in container Ill, the device 62! operates to open the control circuit and de-energize both motors A and B, so that the compressor 33 is stopped.

While a single-stag compressor has here been shown as the means for withdrawing gas from the liquid phase container, such compressor obviously may employ two or more stages to effect the desired degree of pressure elevation. As the degree of pressure elevation to be attained in the compressor is increased, the more important it becomes to use graphite piston rings in order that the compressor may be both properly lubri-,

cated and resistant to combustion with oxygen when under pressure. The use of such rings is believed to be one of the novel features of the invention.

Since certain changes in carryin out the above method and in the constructions set forth, which pressure materially less than 273 K., which comprises maintaining a supply of liquefied gas in a heat insulated container, mechanically withdrawing material in the gas phase from the accumulation thereof within said container when said gas phase has attained a pressure of predetermined high value, elevating the pressure of the withdrawn gas phase to a predetermined service value, continuuing said mechanical withdrawing of gas phase when once initiated until a predetermined low value of the pressure of the gas phase being withdrawn is attained, and withholding such withdrawal of gas phase in the event the head of the service pressure exceeds a predetermined high value.

2. A method of storing and dispensing to servicing connections a gas material having a boiling point temperature at atmospheric pressure materially less than 273 K., which comprisesmaintaining a supply of liquefied gas in a heat insulated. container, mechanically withdrawing material in the liquid phase and supplying the material to said servicing connections to meet a service demand, mechanically withdrawing material in the gas phase when said gas phase has attained a pressure of predetermined high value, elevating the pressure of the withdrawn gas phase and supplying it to said servicing connections at a predetermined service value, continuing said mechanical withdrawing of gas phase when once initiated until a predetermined low value of the pressure of the gas phase being withdrawn is attained, and preventing withd1 awal of gas phase in the event the head of the service pressure exceeds a predetermined high value.

3. A method of providing a supply of and. dispensing to servicing connections for consumption a gas material having a boiling point temperature at atmospheric pressure materially less than 273 K., which comprises maintaining a supply of liquefied gas in a heat insulated container, mechanically withdrawing material in the liquid phase to meet a service demand and maintain a supply of said material thereto at a pressure above a predetermined value, mechanically withdrawing material in the gas phase when said gas phase has attained a pressure of predetermined high value, elevating the pressure of the withdrawn gas phase and supplying it to said servicing connections at a predetermined service value, continuing said mechanical withdrawing of gas phase when once initiated until a predetermined low value of the pressure of the gas phase being withdrawn is attained, and withholding such withdrawal of gas phase in the event the head of the service pressure exceeds a predetermined high value.

4. A method of handling a gas material having a boiling point temperature at atmospheric pressure materially less than 273 K., which comprises maintaining a supply of liquefied gas in a heat insulated container at a low pressure below a predetermined value, mechanically withdrawing material in the gas phase from the accumulation thereof within said container when said gas phase has attained a pressure approaching said predetermined value, elevating the pressure of the withdrawn gas phase to a pressure of predetermined service value, continuing said mechanical withdrawing of gas phase when once initiated until a predetermined low value of the pressure of the gas phase being withdrawn is attained, and automatically preventing the withdrawal of gas phase in the event the head starting said compressor when said pressurehas reached a predetermined high value and for auof the service pressure exceeds a predetermined high value.

5. A\method.of providing a supply of and dispensing to servicing connections for consumption a gas material having a boiling point temperatureat atmospheric pressure materially less than 273 K.,which comprises storing liquefied gas in a heat insulated container, intermittently withdrawing material in the liquid phasefrom said container and delivering the material to said servicing connections as required to meet the service demand, mechanically withdrawing material in the gas phase when said gas phase has attained a pressure of predetermined high value, elevating the pressure of the withdrawn gas phase and delivering it to said servicing connections, continuing said mechanical withdrawing of gas phase when once initiated until a prede-,

termined low value of the pressure of the gas phase being withdrawn is attained, and automatically stopping mechanical withdrawal of gas phase when the head of service pressure is in excess of a predetermined high value.

6. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the.

combination comprising a heat insulated container adapted to receive and store a charge oi' liquefied gas, a gas compressor connected to withdraw gas phase from said container, a liquid heater and vaporizer connected to receive liquid phase withdrawn from said container, a supply line leading from said vaporizer to a place of use, a branch connecting the discharge from said compressor to said supply line, and automatic means for operating said compressor to withdraw gas phase when the pressure in said container has reached a predetermined high value and for stopping the same when said pressure has reached a predetermined low value.

'7. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the

combination comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a gas compressor connected to withdraw gas phase from said container, a pipeline pump connected to withdraw liquid phase from said container, a liquid heater and vaporizer connected to receive the discharge from said pipeline pump, a supply line leading from said vaporizer to a place of use including pressure modifying means, a branch connecting said compressor to discharge into said supply line at a point, downstream of said pressure modifying means, and automatic means for operating said compressor to withdraw gas phase when the pressure in said container has reached apredetermined high value and for stopping the same when said pressure has reached a predetermined low value.

8. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the

-cmbinati0n comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a gas compressor connected to withdraw gas phase from said container, a liquid heater and vaporizer connected to receive liquid phase withdrawn from said container, 9. supply line leading from said vaporizer to a place of use and having a pressure regulator therein, a branch connecting said compressdr to discharge into said suppl y'line at a point downstream to said pressu regulator, means responsive to the pressure in said container arranged for automatically tomatically stopping said compressor when said pressure has reached a predetermined low value, and means responsive to the pressure in said supply line for preventing said automatic means from starting said compressor in the event that said last-named pressure is in excess of a predetermined high value.

9. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the combination comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a gas compressor connected to withdraw gas phase from said container, a pipeline pump connected to withdraw liquid phase from said container, a liquid heater and vaporizer con-' nected to receive the discharge from said pipeline pump, a supply line leading from said vaporizer I to a place of use and having a pressure regulator therein, a branch connecting said compressor to discharge into said supply line at a point downstream to said pressure regulator, means responsive to the pressure in said container arranged for automatically starting said compressor when said pressure has reached a predetermined high value and for automatically stopping said compressor when said pressure has reached a predetermined low value, and means responsive to the pressure in said supply line for preventing said automatic means from starting said compressor in the event that said last-named pressure is in excess of a predetermined high value.

10. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the combination comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a gas compressor connected to withdraw gas phase i'rom said container, a liquid heater and vaporizer connected to receive liquid phase withdrawn from said container, a supply line leading from said vaporizer to a place of use and having a pressure regulator therein, a branch connecting said compressor to discharge into said supply line at; a point downstream to said pressure regulator, a normally'open valve controlled by-pass about said compressor leading into said supply line, and automatic means responsive to the pressure in said container for actuating said compressor and provided with means for closing said by-pass valve.

11. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K., the combination comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a gas compressor connected to withopen valve controlled by-pass about said com-' pressor leading into said supply line, automatic means for actuating said pipeline pump in response to a service demand, additional automatic means responsive to the pressure in said container for actuating said compressor, and means for closing said by-pass valve.

12. In apparatus for dispensing a gas material having a boiling point temperature at atmospheric pressure materially below 273 K the combination comprising a heat insulated container adapted to receive and store a charge of liquefied gas, a'gas compressor connected to withdraw gas phase from said container, a supply line connected to withdraw said material in the liquid phase from said container, a liquid heater and associated with said additional automatic means vaporizer in said line. a. connection for said'supply line for delivering the vaporized material to a place of use, a branch connecting the discharge from said compressor to said supply line, and automatic means for operating said compressor to withdraw gas phase when the pressure in said container has reached a predetermined high value and for stopping the same when said pressure has reached a predetermined low value.

GEORGE JOHN BOSHKOFF.

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