US2018144A

US2018144A - Method and apparatus for transferring gas material

Info

Publication number: US2018144A
Authority: US
Inventors: William F Mesinger
Original assignee: Linde Air Products Co
Current assignee: Linde Air Products Co
Priority date: 1933-04-29
Filing date: 1933-04-29
Publication date: 1935-10-22
Anticipated expiration: 1952-10-22
Also published as: FR771813A; DE612709C

Description

Oct. 22, 1935. w. F. MESINGER 3 Sheets-Sheet 1 Filed April 29, 1933 5 R m m N 4 R w a. m

Oct. 22, 1935. w. F. MESINGER 9 3 METHOD AND APPARATUS FOR TRANSFERRING GAS MATERAL Filed April 29, 1933. I 3 Sheets-Sheet 2 INVENTOR i W ATTOW/ Patented Oct. 22, 1935 METHOD AND APPAEATUS FOR. T RANS- FERRING GAS MATERIAL William F. Mesinger, Phishing, N. Y., ainor to The Linde Al- Products Company; .New York, N. Y., a co'poration of Ohio Application April 29, 1933, Serial No. 668.668

claims.

This invention relates to a method and ap-` paratus for transferring` gas material, particularly gas material in the liquid phase which can be stored under atmospheric pressure only when 5 the temperature is below 273 K.

The invention has for its principal object to provide an improved method and apparatus for transferring gas material of the character indicated from containers in which it is held to deo vices or vessels adapted for receiving the same at a relatively high pressure.

More particularly, it is an object to provide a method and suitable apparatus by which a liquefled gas may be transferred by means of a force applying device such as a pump, from a container in which the liquid has been stored or transported at a relatively low pressure, to a device adapted to cause vaporization of the liquefled gas at a relatively highpressure.

Another object is to provide improved apparatus for pumping liquefied gases in liquid phase of a character which avoids having the pumping means become gas bound and which provides for the reduction in number of the moving parts and for their lubrication.

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 one or more of such steps with respect to each of the others, and the apparatus embodying features of Construction, combinations of elements and arrangement of parts which are adapted to efiect such steps, all as exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of 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: i

Fig. 1 is a view mainly in section showing an apparatus for holding a liquefled gas and for iorcing it in the liquid phase to receiving means in accordance with the invention;

Fig. 2 is an enlarged fragmentary view mainly in section 'of a portion of the apparatus shown by Fig. 1 including the forcing means;

Fig. 3 is a View mainly in section with portions broken away of *a modified form of apparatus constructed in accordance with the invention;

Fig. 4 is a view of a section taken on the line 4-4 of Fig. 3 through a portion of the apparatus; and

Flg. 5 is a view mainly in section with portions broken away of another modification o! apparatus constructed in accordance with the invention.

Heretofore, when it was desired to transfer liquefied gas from storage containers to receiv- I ing devices Operating at a relatively high pressure, it was necessary to raise the pressure in the storage container to a value suflic'iently higher than the pressure in the receiver to cause the flow to occur. To withstand this pressure. it o was necessary to provide a storage container having very strong and thick walls, so that its cost and weight were great. Attempts to pump the liquefled gas from a low pressure container with pumps of the type commonly used for pump- 16 ing liquids were not successful because of the tendency oi the liquefled gas to flash into vapor in the pump casing whereby it became gas bound".

By the method and with the apparatus of the 20 present invention, a liquefled gas may be transported in a container at substantially atmospheric pressure and forced into vaporizing and receiving devices at the destination without incurring the disadvantages attending such prior 25 methods. This is accomplished by providing the forcing device in the base of the storage and transport container, or in a container associated with the transport container, maintaining its walls at substantially the temperature of the 30 liquefied gas, and efiectng the venting of the vapors from the forcing chamber when it fllls with a charge of liquefled gas in a manner to expedite the transfer.

Referring now to the drawings and particu- 35 larly to Fig. 1, there is shown a body of liquefied gas o held within a container ll, which is surrounded by an envelope of heat insulating material !2. To support the insulating material and to furnish means by which the container ll 40 is supported within the insulating envelope with a desired degree of rigidity, there is provided an outer casing !3, preferably of metal and supports M attached at one end to the container and at the other to the casing. This container 45 may be mounted upon a vehicle so that the liquefied gas material may be transported to a place where a deslred portion is to be discharged to a receiving device, or it may be mounted as a stationary storage container for storing the liquefled gas during periods when no liquid is being discharged. Meansfor filling the container comprises a normally plugged filling connection ll' leading to the interier. Means for discharging material in the gas phase, draining off liquid, 55

and for indicating the quantity of liquid therein are provided but not shown in the interests o! cleamess of illustration.

Mounted in the base of container Il is a liquid Iorcing means comprising a pump housing !5 within which a reciprocating fluid displaclng element s, here shown in the form of a fltted piston, is arranged to move. The housing |5 is provided with means for admitting liquid and for venting vapor which comprise, in this form ot apparatus, inlet ports l'l uncovered by the piston IG upon its up stroke and one or more vapor outlet ports s also uncovered by the piston when the inlet ports are uncovered. The relation ot these parts is more clearly shown in the enlarged view of Fig. 2. The piston is shown in an extreme upper position and is provided with a recessed portion s registering with port s so that, in the position shown, liquid will freely enter the housing while vapors. displaced are vented by way of port !8 and conducted by a conduit 20 to the vapor space above the body of liquid.

The housing |5 is preferably mounted in a sump or depression 2| provided in the lower portion of container ll. The housing is here shown to be held in a fluid-tight manner to the floor of sump 2I by means of the valve housing 22, which has a threaded neck 23 of reduced diameter passing through the floor of the sump and threadedly engaging an opening in the base of the pump housing. The valve housing is provided with a passage 24 controlled by a valve element 25 that' is normally held closed by spring 20. A cap 21 seals the end opening of passage 24 and holds in place the spring retaining and valve stern guiding means 28. A conduit 29 opening into the side of the valve housing 22 is provided to conduct gas material discharged to the outside of casing l I. The casing ll may be provided with a hand hole and cover at a point opposite the cap 21 to provide for ready access to the discharge valve.

The piston !6 is preterably made hollow, the outline of the interier space being indicated by dotted lines. A long vertical piston rod 30, Joined to the top of piston !6 preferably by a ball and socket joint for permitting the piston to have a degree of freedom for self alignment while transmitting the reciprocating motion, traverses diametrically the container, passing through its upper portion where a gas-tight seal 3l is provided. The seal 3l comprises an accordion-like corrugated metal bellows joined in a gas-tight manner to the rod at one end and at the other to a flange 32 which is clamped between a perforated closure plate 33 and the lower portion of guide sleeve 34. The closure 33 serves to seal an opening in the container wall large enough for thepassage of pump housing !5. sleeve 34 is made long enough to pass through the insulation I2 to the outside of casing l3 at the upper portion where it is provided with a monitor top 35 for the purpose of increasing the insulation thickness at that point.

The increased thickness is desired to provide a longer path for the conduction of heat from the atmosphere to the container along the path comprising the sleeve 34 and the rod 30, since these parts, while made of materials having relatively low conductivity, conduct heat more readily than the insulating material where the paths tor the conduction of heat are equal in length.

The rod 30 may be constrained to assume the desired reciprocating motion by various means, for example, as shown diagrammatically herein, where the end of rod 30 is reciprocated by a connecting rod and crank disk assembly 36 that is &018,144

driven by an electric motor 31 through the medium of a worm and wheel type of speed reduction gear 38. At the outer end of sleeve 34 there is provided a packing gland tor retaining a packing that excludes moisture laden air from the cham- 5 ber within the bellows 3I. A pressure release valve 33 is provided in communication with the container for releasing excesslve pressure.

In operation, the piston and housing !5, being submerged in the liquefled gas. are maintained 107 at 'substantially the temperature of the fluid and their surfaces are lubricated by the liquid. When. the piston reaches the highest point of its stroke, liquid runs in at ports l'l while displaced vapor fluids escape through port s, passing up through 1 conduit 20 to the vapor space above the liquid !0. since it is desirable to avoid heating the liquid, the vapors are not permitted to bubble through the liquid, but are conducted direct to the vapor space above the liquid where they produce a rela- 20 tively more rapid increase in pressure above the liquid for the purpose of assisting the flow of liq-` uid into the pump housing !5 through inlet ports l'l. Thus, heat generated in the pump housing is transferred to the gas space above the liquid 5 where it becomes useful to assist the pumping. As the piston descends, the ports are gradually closed by the piston'and when they are closed, the liquid that has been trapped in the pump housing will be forced out through the valve housing 22 0:;

into conduit 29 which conducts the fluid to the receiving device at the desired high pressure. The liquid that is trapped in the clearance space of the pump at the end of the stroke is moderately heated by the work of compression and partly 35'j unsupported portion of rod 30 with bracket bearing means or with stifiening means such for example as tubular columnar Construction. When the piston has reached the lower limit of its stroke', the valve element 25 will be returned to its seat so that back flow of fluid from conduit 29 3 into the housing during the upstroke of the piston is prevented. As the piston moves upward, part of the liquid which remained in the clearance space or passage 24 being moderately heated by the work of compression, will flash into vapor due 50 to the reduction of pressure. This vapor subscquently escapes at port !3 when the piston has returned to its upper limit and is conducted to the gas space above the liquid.

. When it is desired to pump certain liquefled- 5 gases, for example, those which possess relatively poor lubricating properties, it may be desirable to provide the fluid displacing means in the form of a plunger, in which case the liquid inlet and the vapor escape ports are preierably controlled by 00 valve means mechanically operated.

A modified form of container having in its base a liquid forcing means according to the invention is shown in Fig. 3. Here; the filling connection is shown at III' leading into the container III, 65 while the casing l|3 is made to have a modified shape. The forcing means designated generally by B here comprises a horizontal double acting pump having a housing 40 within which a fitted piston 4| is disposed and arranged to be recipro- 70 cated.

Ports

42 and 43 opening into the bore of the housing are located midway between the ends of the bore. The piston 4| is made of such length that it substantially fllls the bore at one side oi' the ports when it is at that end oi' its stroke, i

so that the ports are uncovered by the ends of the piston each time it reaches an end of its stroke. The ports 42 when uncovered permit the flow of liquid into the portion of housing 40 that is vacated by the piston, while the upper port 43, to which is connected a conduit 20 for leading gas material to the vapor space of the container, permits the displaced vapors to escape.

Around housing 40 is formed a passage 44 communicating at its top with the liquid space of the container III. This passage is shown more clearly in the sectional view of Fig. 4. The liquefied gas thus surrounds the housing 40, maintaining its walls substantially at the liquid temperature' and enters the ports 42. In each end or head of housing 40 there is a discharge passage 45 controlled by a spring closed valve 46. These valved passages discharge into a connecting passage 41 that leads gas material to a common discharge conduit 29 for conducting the gas material at higher pressure to the receiving device. Above the valves 46 are disposed removable closures 48 that permit ready inspection and adjustment of the valves. Accessto these closures 48 is readily attained without removing the container I I l from its envelope by partitioning off compartments 49 and`50 which hold away the insulating material !2 and have covers 5| and 52. A piston rod 53 for transmitting the reciprocating motion of crosshead 54 to the piston is attached at one end to piston 4| and at the other to crosshead 45 and passes through one head of pump housing 46 through a packing box 55 containing a suitable packing which is compressed by gland 56. The crosshead 54 works between the guide members of a frame 51 that is mounted outside of the casing I !3. At the point where rod 53 passes through the casing wall, there is provided a packing box 58 with packing to prevent access of untreated at mospheric air to the interior of the casing. The crosshead is reciprocated by means of the connecting rod 59 and crank disk 60, which is driven by any suitable power means such as an electric motor. supporting struts 6! between the pump B and the frame 51 are provided for transmitting the thrust reaction of the piston to the crank disk bearings.

In the operation of this form of forcing means, the liquid fills one end, for example the crank end, of the pump housing through the uncovered ports when the piston is at the other end. When the piston returns, the ports are first closed off and then the liquid remaining in the crank end is forced out through the discharge passage to the receiving device. v When the piston arrives at the crank end, the ports are again uncovered, but the gas material fiows now into the vacant head end of the housing. All gas material that leaks by the piston is not lost, but fiows into the opposite end of the housing.

In Fig. 5 is shown apparatus where another form of double acting liquid pump, indicated generally at C, is disposed in the base of a liquefied gas container 2|| having an envelope of insulation I2 and casing 213. The pump housing 63 is provided with

cylindrical bores

64 and 65 in each of which a head of the piston is adapted to operate. The piston comprises two

head portions

66 and 61 connected by a portion 68 in a manner to allow an eccentric 'cam 69 to rotate between the rear faces of the heads. The cam 69 rotates about the centerline of shaft 10, to which it is attached by suitable means, as a key. To avoid rubbing riction, it is preferred to provide a roller hearing surrounding the cam having an outer ring 'll The cam 69 when rotated causes the piston to oscillate from side to side. The shaft 10 rotates in anti-friction bearings held in a hub 12 that is Joined to the housing by sup- 5 porting webs having passages for the flow of liquefled gas into the central portion of housing 63. The central chamber of housing 63 is formed with clearance pockets at each side to accommodate and provide clearance for the ring '|l. 10 Liquefied gas that flows into this chamber is con-` ducted to separate inlet ports 13 for each

end

63 and 65 of the housing by passages 14. These ports, as well as gas outlet ports 15, are so located that they are uncovered by the edge of the re- 5 spective piston head when the piston is at an extreme limit of its travel. Vapors released at ports 15 are conducted by passages 16 to conduits 220 which conduct them to the vapor space above the liquid in the container zl i. against heat transfer with the liquid, the conduits 220 may be disposed around the outside of container zl i to join same at its upper portion. Fluid is discharged from ends 66 and 65 through passages TI, which are normally closed by means of 25 spring pressed valve elements 18. The fluid forced by the valve elements is conducted by a common connecting conduit 19 to the discharge conduit 29 leading to the outside of the casing. Access to the valve chambers for adjusting the 30 valves is provided as in the previously described forms by removable closures 66, partitions sl, and closures 82.

shaft 10 is driven by a vertical extension shaft 83, to which it is coupled by a flexible coupling 35 84. shaft 83 passes to the outside of the casing, traversing the wall of the container, the envelope of insulation and the wall of the casing which is formed with a monitor top 'portion 05 for accommodating a greater thickness of insulating mate- 40 rial l2 at this point. A tubular casing 86 for holding away insulation and for forming a gastight seal surrounds the portion of shaft 83 passing through the insulation space. casing 86 is provided at its outer end with a packing and 45 gland 61 for preventing the loss of gas material while allowing the shaft to rotate. The upper portion of shaft 83 is guided by hearing 88 held by a supporting bracket 89. The end of the shaft is keyed to a gear 00 that meshes with pinion 9| 50 which is driven by any suitable power means, for example, an electric motor, or when this container is mounted on a motor truck, the pinion may be driven from the truck engine through the medium of a power ofi-take and transmission 55 device. This form of the apparatus has the advantage that the drive shaft does not reciprocate, and though double acting, the pump is driven from the low pressure side, that is, the drive shaft packing is subjected to relatively low pressures and may be located where it remains comparatively warm. The thrust reactions of forcing the liquid are counterbalanced within the pump itself. In cases where it is desired to transport the main body of liquefied gas at atmospheric pressure, it; is desirable to construct the container of the present invention large enough to hold only the quantity of gas material to be pumped out 'at one locality and carry the main body of liquefied gas in a large transport container associated with the pumping container. The operation except for difierences due to construction, is similar to that of the other forms.

Since certain changes in carrying out the above process and in the constructions set forth, 7

To better insure 20 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 means of a pump having a fluid displacing element from a container adapted to be normally closed but open to the atmosphere during a filling operation to an external point, which method comprises positioning the pump so as to be subject to the temperature of the liquefied gas, excluding substant-ially all heat of external origin from the pump, and transferring heat or pumping generated by the pump by gas evolved therein i to the upper part of the container where it assists in doing the work of transferring liquid, whereby the pump may be operatedat a relatively high efliciency to force liquid to an external point against a relatively high head of pressure.

2. A method of transferring a liquefied gas, which' can be stored under atmospheric pressure only when the temperatureis below 273 K., by means of a pump having a reciprocating element 'clearing a, space for 'the reception of a charge,

from a container adapted to be normally closed but open to the atmosphere during a filling operation to an external point, which method comprises positioning the pump so as to be substantially at the temperature of the liquefied gas, excluding substantially all heat of external origin from the pump, venting the pump with the reception of each charge and transferring the gas together with any heat generated in the pump to the upper part of the container, whereby the pump operates without becoming gasbound at a relatively'high eiiiciency to force liquid to an external point against a. relatively high head o! pressure.

3. A method of transferring a lquefied gas, which can be stored under atmospheric pressure only when the temperature is below 273" K., by means of a pump having a reciprocating element clearing a space for the reception oi' a charge, from a container adapted to be normally closed but open to the atmosphere during a filling operation to an external point, which method comprises positioning the pump so as to be substantally at the temperature of the liquefled gas, insulating said pump and container to exclude substantially all heat of external origin, venting the pump with the recepion of each charge and transferring the gas together with the heat o! pumping` generated in the pump to the upper part of the container, whereby the pump may be operated without becoming gasbound at relatively high efliciency to force liquid to said external point against a relatively high head oi' pressure.

4. Apparatus for transferring gas material in the liquid phase, which can be stored under atmospheric pressure only when the pressure is below 273 K., comprising, in combination, a heat insulated container adapted to hold the liquid to be stored, a pump casing disposed in said container and having an inlet communicating with the container at a. point near the bottom thcreof, a pisten arranged to reciprocate in said casing and 'open said inlet when moved to a position such as to clear substantially a. maximum space !or the reception of liquid from the container, a pisten rod i'or said piston leading to a point on the exterior oi' said container, means for venting said pump caslng leading !rom an opening therein substantially in the same plane as said inlet, 5

mechanical means on the exterior of said casing for actuating said pisten rod, a discharge connection leading !rom the bottom .ot said pump casing, and a normally closed discharge valve controlling the 'connection between said discharge 10 and pump casing arranged to open under pressure.

5. Apparatus !or transferring gas material in the liquid phase, which can be stored under atmospheric pressure only when the pressure is 15 below 273 K., comprising, in combination, a heat insulated container adapted to hold the liquid to be stored, a pump casing having an inlet communicating with the container at a point near the bottom thereof, a piston arranged to recipro- 20 eate in said casing and open said inlet when moved to a position such as to clear substantially a maximum space for the reception of liquid from the container, a piston actuating means having a rod leading to a point on the exterior OI 25 said container, means for scaling said container at the point where said rod passes therethrough against the escape of gas, means for venting said pump casing leading -from an opening uncovered by said piston at substantially the same instant said inlet is opened, said venting means leading to a point in the space in said container above the normal liquid level therein, mechanical means on the exterior of said casing for actuating said rod, a, discharge connection leading from the bottom of said pump casing, and a. normally closed valve controlling the connection between said pump casing andsaid discharge connection.

6. Apparatus for transfe'rring gas material in mospheric pressure only when the pressure is below 273 K., comprising, in combination, a heat insulated contalner adapted to hold the liquid to be stored, a pump casing disposed in said contair'er and having an inlet communicating 4 with the container at a point near the bottom thereof, a piston arranged to reciprocate in said casing and open said inlet when moved to a position such as to clear substantially a maximum space for the reception of liquid from the 50 container, a pisten rod tor said piston leading to a point on the exterior of said container, an expansible bellows for sealing said 'container at the point where said pisten rod passes therethrough against the escape of gas, means for 55 venting said pump casing leading from an opening uncovered by said piston at substantially the same instant said inlet is opened, said venting means leading.to a point in the space in said container above the normal liquid level therein, 60 mechanical means on the exterior of said casing for actuaiing said pump piston, a discharge connection leading from the bottom of said pump casing, and a normally closed valve controlling the connection between said pump casing and 65 said discharge connection.

7. Apparatu's for transferring gas material in the liquid phase, which can be stored under atmospheric pressure only when the pressure is below 273 K., comprising, in combination, a 70 heat insulated container adapted to hold the liquid being stored, a pump casing disposed in said container and having inlets communicating with the container at a point near the bottom thereof, a. piston comprising two head portions 75 joined by a portion of reduced section arranged to reciprocate in said casing and to open said inlets for communication with spaces cleared by the head portions for the reception of liquid from the container, an eccentric cam element disposed between said head portions and arranged to cause reciprocation of said piston when rotated, a shaft for rotating said eccentric element leading to a point on the exterior of said casing. means for rotating said shaft, means for venting said casing leading from ports opened by said pisten heads at the same instant that the corresponding inlets are opened, said venting means leading to the space in said container above the normal liquid level therein, and discharge openings in each end of said casing normally closed by non-return valve elements.

8. Apparatus for transterring gas material in the liquid phase, which can be stored under atmospheric pressure only when the pressure is below 273 K., comprising, in combination, a heat insulated container adapted to hold the liquid being stored, a pump casing horizontally disposed within heat insulation and having inlets communicating with the lower portion of said container, a piston comprising two head portions joined by a portion of reduced section and arranged to reciprocate within said casing so that said head portions open said inlets for communication with spaces cleared by the head portions for the reception ot liquid from the container. an eccentric cam element dispos'ed between said head portions and arranged to reciprocate said piston when rotated, a shaft joining said eccentric element for rota-ting same, power means !or rotating said shaft, means for venting said casing leading from ports opened by said piston heads at the same instant that the corresponding inlets are opened, said venting means leading to the space in said container above the normal liquid level therein, discharge passages leading from each end of said casing to receiving means, and normally closed valve elements controlling said passages.

9. Apparatus !or transferring gas material in the liquid phase, which can be stored under atmospheric pressure only when the temperature is below 273 K., comp'ising. in combination. a

heat insulated container adapted to hold the liquid to be stored having a filling opening provided with a closure whereby it may be closed against the atmosphere, a pump positioned to be maintained at the temperature of the liqueed 5 gas material by thermal contact with stored liquid, said pump having a casing and a fluid displacing element reciprocating thereinand provided with an inlet communicating with said container at a point near the bottom thereof, means for reciprocating said element, means for venting said pump casing to the upper part of said container when said element has moved to clear a space for the reception of liquid and opens said inlet whereby gas generated by the heat of pumping is supplied to the upper part of said container and builds pressure, and a discharge connection leading from said pump casing having a normally closed discharge valve controlling the same. 10. Apparatus for transferring gas material in the liquid phase, which can be stored under atmospheric pressure only when the temperature is below 273 K., comprising, in combination, a heat insulated container adapted to hold the 2 liquid to be stored having a filling opening provided with a closure whereby it may be closed against the atmosphere, a pump positioned to be maintained at the temperature of the liquefied gas material by thermal contact with stored liq- 80 uid. said pump having a casing and a fluid displacing element reciprocating therein and provided with an inlet communicating with said container at a point near the bottom thereof, means for reciprocating said element, means for 8 venting said pump casing to the space above the normal liquid level in said container whereby pressure may be built within said container above the liquid discharging, said element being arranged wlthinsaid casing so as to open both said 40 inlet and venting means when said element has moved to a position which clears substantially a maximum space for the reception of liquid from said container, a discharge connection leading from said pump casing, and means for maintaining said discharge connection normally closed against return flow of fluid.

WILLIAM F. MESINGER.