US3097498A

US3097498A - Apparatus for handling liquefied cases

Info

Publication number: US3097498A
Authority: US
Publication date: 1963-07-16
Anticipated expiration: 1980-07-16

Description

y 6, 1963 D. A. WILLIAMS 3,097,498

APPARATUS FOR HANDLING LIQUEFIED CASES Filed June 29, 1959 2 Sheets-Sheet 1 July 16, 1963 D. A. WILLIAMS APPARATUS FOR HANDLING LIQUEFIED CASES Filed June 29, 1959 2 Sheets-Sheet 2 INVENTOR. DAV/o A. W/LL/AMS United States Patent Oil ice 3,097,498 Patented July 16, 1963 3,097,498 APPARATUS FOR HANDLING LIQUEFIED GASES David A. Williams, Wheaten, Ill., assignor to Chemetron Corporation, Chicago, 111., a corporation of Delaware Filed .iune 29, 1959, Ser. No. 823,664 6 Claims. (Cl. 62-55) This invention relates to fluid handling systems for volatile liquid having a boiling temperature at atmospheric pressure materially below 273 K., and more particularly to a system for supplying a liquefied gas having a normal boiling point below 233 K., such as liquid oxygen, nitrogen and the like to a receiver from a main supply tank. Such a system is particularly useful in the apparatus described in copending United States Patent application Serial No. 823,400 of the present applicant and Lester C. Browning, entitled Apparatus for Handling Liquefied Gases, filed of even date herewith and assigned to the same assignee as the present invention.

One of the unique properties of liquefied gas having a boiling point below 233 K. is that the critical temperatures of the majority of such liquefied gas is well below normal ambient temperatures. Thus, whenever liquefied gas is permitted to come in contact with pipes, containers, or machinery which is near to ambient temperatures, some of the liquid will be changed into a gas by its absorption of heat. When this liquid changes to gas a large increase in volume takes place, or if the volume is limited a large pressure increase will take place. Difficulty has heretofore been experienced in supplying a receiver with liquefied gas when the receiver is remote from the supply tank in that vaporization of the liquid may occur in the system. In the past it has been necessary to provide two lines from the supply tank to the receiver, one to carry off the vapor.

t is, therefore, an object of the invention to provide an improved handling system for liquefied gas having a boiling point below 233 K.

A more specific object of the invention is to provide a handling system for supplying liquefied gas to a receiver remote from the supply tank which system requires only one line from the supply tank to the receiver.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly stated, in accordance with the invention, the fluid handling system includes a receiver such as a vessel or pump remote from a supply tank and connected to be filled from the supply tank with liquid gas having a boiling point below 233 K. A fluid trap below the liquid level of the supply tank has its inlet in communication with the tank below the liquid level thereof and has its outlet discharging through a supply line into the receiving vessel. The fluid level of the receiving vessel is below the discharge of the fluid trap. A vent conduit connects with the highest point of the supply line to remove gas formed in the system.

The nature of the invention will best be understood when described in connection with the accompanying drawings, in which:

FIG. 1 is a schematic elevational view, partly in section, of a liquefied gas handling system according to one embodiment of the instant invention;

FIG. 2 is a schematic elevational view, partly in section, of a liquefied gas handling system incorporating a second embodiment of the instant invention;

FIG. 3 is a schematic elevational view, partly in section, of a liquefied gas handling system incorporating another embodiment of the instant invention; and

FIG. 4 is a schematic elevational View, partly in section, of a liquefied gas handling system incorporating yet another embodiment of the instant invention.

Referring to the modification of FIG. 1, a receiver, shown as a receiving vessel 10, is connected to be kept full of liquefied gas when located remote from a main supply tank 11. Vessel 1t}; and tank 11 are each contained within a vacuum or insulation space defined by outer shells 12, 13 respectively. The supply tank 11 is at least partially full of liquefied gas 14; above the liquid is a gas 15 which may contain the vapor from the liquefied gas.

A fluid trap 16 has its inlet 17 communicating with the liquefied gas 14 in the supply tank and has its outlet or discharge 18 connected through a main supply line or conduit 19 to discharge into the top of the receiving vessel 10. A shut-off valve 20 is in the main line 19 between the discharge 18 of the trap 16 and the receiving vessel 19. It may be desirable to have a safety pressure relief valve 21 in communication with the receiving ves sel 10. A vent line or conduit 22 connects with the highest point on the supply line 19 between the discharge side 18 of the fluid trap 16 to vent the vapor or gas which may be evolved in the system. As shown, the vent line 22 returns the gas to the supply tank 11 above the liquid gas level 14. It is to be understood, however, that where it is not desired to save the gas formed in the system, the vent line 22 may be returned to the atmosphere. Vent line 22 contains a shut-off valve 23 and may also contain a safety pressure relief valve 24 in communication with the supply tank 11.

As is common cryogenic practice, the fluid trap 16 is contained within the insulation space defined by outer shell 13 around the supply tank 11. When

valves

20 and 23, external to the tank, are closed, the liquefied gas within the supply line 19, exterior to the insulation jacket enclosed by outer shell 13, will, because of absorbed heat, be partially vaporized into the gaseous state. This gas evolved will then fill the portion of conduit 19 between the tank 11 and the two

valves

20 and 23 and will thereby force the liquefied gas level in the fluid trap 16 to recede to point A which is protected against heat loss by the insulation within insulation space 13. The heat absorption loss by the liquefied gas in the suply tank 11 will then be greatly reduced. When it is desired to maintain the receiving vessel 10 full of liquid, valve 20 is opened. This will permit liquefied gas to flow into the receiving vessel until suificient gas has been evolved to raise the pressure of this external system to equal that at point A. If valve 23 is then opened, the gas which has been evolved in this system will be allowed to return by way of vent line 22 to the gas space 15 above the liquefied gas 14 level within the supply tank 11.

Liquid will now flow to the receiving vessel 10 and the vessel will be maintained full because the gas evolved in the receiving vessel 11) and supply line 19 will be permitted to return to the gas space 15 of the supply tank 11 as rapidly as it is formed. In this manner a receiving vessel remote from the supply tank can be maintained full of liquefied gas with only one line connecting the vessel and the tank.

It may be desirable, but not necessary, to provide a fluid drain line for the receiving vessel. This line will come into use when it is desired for economical reasons to return the liquefied gas Within the receiving vessel to the supply tank at the end of an operating cycle. Such an arrangement is illustrated by the drain line 25 having one end connecting with the bottom of the receiving vessel 10 and having its other end connecting with the discharge side 18 of the fluid trap 16 on the side of

valves

20 and 23 nearest to the discharge 18. The line 25 contains a shut-off valve 26. When it is desired to drain the receiving vessel 10, it is merely necessary to close valves 20 [leading out to the top of the float chamber 30.

and to open H The boiling of the liquefied gas in the receiving vessel due to heat absorption will create a pressure build-up in the vessel lit. The gas ,eyolved willrise to the top of the vessel and the pressure in the upperpart of the vessel will be increased until the liquid remaining in the vessel ispushed back into the supply tank through drain line25 and valve 26. This will result a minirnum loss of the liquefied gas.

and,condui t 25 may be quite smalliand may be routed to Valve 26 the main supply tank 11 close to the main supply line 19 so thatiines25 and 19 can be thoroughly insulated to ,,redu'c e heat infiltration into the liquefied gas.

. FIG, 1, except that a float valve 28 is inserted in the vent line22, and the receiver is illustrated as a pump 29. The ,vent line 22 connects to the supply line 19 at the high ,point of the supply line 19.

The float valve 28 results in automatic operation of the vent line 22. In order to supply liquefied gas to the pump 29, valve in supply ,line 19 and valve 23 in vent line 22 are opened. The gas ,evolved in this system will pass through supply line 19 into float chamber 30 ofvalve 28 forcing the liquid level in the chamber, to drop thereby lowering the float 31 and opening the v,vent line 22. The gas evolved will now be vented back to the ,upper part of the supply tank 11. The level of liquidwithin the float chamber will rise to a point at which the float 3-1 will shut off the opening to the line 22 In the event of further evolvement of gas in the system, this gas ;will enter, the float chamber at the bottom and the liquid level, in, the float chamberwill then drop. This will in ,turn allow the float 31 to drop which will open the chamber 30 to the gas venting line 22.

- Such a, modification results in automatic operation of the vent line. The system has the advantage that the i amount of piping containing cryogenic liquid can be limited to the extent that the gas vent line 22 above the float, chamber 30 does not stand full of liquid. The

weight of the float must be such that the static head of liquid which would be developed between the point at -which the vent line 22 is obstructed by a rising float and the uppermost level of liquid in the supply tank 11 would be insufficient to keep the float in the closed position.

, The float must also be light enough so that the rising liquid can make this float rise with the surface of the liquid due to the displacement ofthe liquid involved.

,The embodiment illustrated in FIG. 3 is identical to 7, that of FIG. 2 except that the vent line 22 vents to the atmosphere.

FIG. 4 illustartes a modification similar to FIG. 2

except that the float chamber 30 is part of the supply line 19 rather than in the vent line 22. The method of operation is essentially the same as that of FIG. 2. When the gas is vented from the float chamber 30, the liquid level within the float chamber will rise and close the float valve 2 8. When sufficient gas is evolved in this system to lower the level of the liquid in the float chamber 30,.the float 31 will drop, thus opening the valve '28 and venting the gas.

While there has been described and illustrated preferred embodiments of the instant invention, it will be expected that various changes and modifications can be made therein without departing from the. scope of the invention,

Which should be limited only by the claims annexed to within an insulation jacket adapted to be at least partially filled with fluid in the liquid state, a fluid trap below the liquid level of said tank having inlet means in communication with said tank below the liquid level thereof and having discharge means, a receiving vessel remote from and independent of said tank adapted to be supplied with said fluid, the fluid of said receiving vessel being below the discharge means of said fluid trap, first conduit means directly connecting said discharge means to said receiving vessel, and second conduit means connected to said first conduit means at the high point thereof andexternal of said jacket and connected to said tank above the liquid level thereof venting said first conduit s i i 1 2, Apparatusfor handling liquefied gas having a boiling temperature below 233 K., comprising a supply tank within an insulation jacket adapted to be at least partially filled with fluid inthe liquid state, a fluid trap below the liquid level of said tank having inlet means in communication with said tank below the liquid level tank above the liquid level thereof for venting said first conduit means,v a float operated valve within a float chamber which is opened by the evolution ofgas in the system .to ventsaid gas through said second conduit Ineans,.said

float chamber being in said first conduit means and said second conduit means venting from the top of said chamber, and shut-ofl valve means in each of said conduit means. 3 ,l V

I 3. Apparatus forhandling liquefied gas having a boiling temperature below 233 K., comprising a supplytank within an insulation jacket adapted to be atleast partially filled with fluid in the liquid state, a fluid trap'below the liquid level of said tank having inlet means;in communication .with said tank below the liquid level thereof and having discharge means, a receiving vessel remote from and independent of saidtank adapted to be filled with said fluid, the fluid of said vessel being below the discharge means of said fluid trap, first conduit means connecting said discharge means to said vessel, second conduit means connectedto-said first conduit means externally of said insulation jacketconnecting said first conduit means and said tank above the liquidlevel thereof, a fluid drain line connected between the bottom of said vessel and saiddischarge means, and shut-elf valve means in said fluid drain line. v

4. Apparatus for handling liquefied gas comprising a supply tank within aninsulation jacket and adapted to be at least partially filledwith fluid in the liquid state, a fluid trap within said jacket and located below said tank having inlet means in communication with said tank and having discharge means, apump located below and remote from said tank for receiving said fluid, first conduit means connecting the discharge of said trap with said pump, shut-off valve means in said first conduit means, secondconduit means connecting the high point on said first conduit means with the top of said tank, a float chamber in said second conduit, -a float valve in i said chamber actuated by the level of liquid therein to means connecting the discharge of said trap with said pump, shut-elf valve means in said first conduit means, a float chamber in the high point of said first conduit means, a second conduit means connecting said high point with the top of said tank, a float valve in said chamber actuated by the level of liquid therein to open or close sa-id sec-0nd conduit means, and shut-off valve means in said second conduit means.

6. In apparatus for handling liquefied gases having boiling points below 233 K., a supply tank within an insulation jacket adapted to be at least partially filled With liquefied gas in the liquid state, a fluid trap below the liquid level of said tank having inlet means in communication with said tank below the liquid level thereof and having discharge means, a receiving vessel remote from and independent of said tank adapted to be supplied wi-th said liquefied gas, the liquefied gas of said receiving vessel being Wholly below said discharge means, and gravity transferring means for transferring liquefied gas from said supply tank to said receiving vessel solely by gravity flow with only a single conduit connecting said supply tank to said receiving vessel, said transferring means including a first conduit connecting said supply tank discharge means to said receiving means, a second conduit connecting the high point of said first conduit to the tank above its liquid level, and shut-off valves in said first and said second conduits external of said insulation jacket, whereby on opening of said valves liquefied gas will transfer from said supply tank through said first conduit to said receiving vessel While gas evolved during the transfer will return to said supply tank through said second conduit.

References Cited in the file of this patent UNITED STATES PATENTS 2,021,271 Thomas Nov. 19, 1935 2,435,332 Van Vleet et al. Feb. 3, 1948 2,487,863 Garretson Nov. 15, 1949 2,576,985 Wildhack Dec. 4, 1951 2,705,873 Bonnaud Apr. 12, 1955 2,848,879 Hesson Aug. 26, 1958

Claims

1. APPARATUS FOR HANDLING LIQUEFIED GAS HAVING A BOILING TEMPERATURE BELOW 233*K., COMPRISING A SUPPLY TANK WITHIN AN INSULATION JACKET ADAPTED TO BE AT LEAST PARTIALLY FILLED WITH FLUID IN THE LIQUID STATE, A FLUID TRAP BELOW THE LIQUID LEVEL OF SAID TANK HAVING INLET MEANS IN COMMUNICATION WITH SAID TANK BELOW THE LIQUID LEVEL THEREOF AND HAVING DISCHARGE MEANS, A RECEIVING VESSEL REMOTE FROM AND INDEPENDENT OF SAID TANK ADAPTED TO BE SUPPLIED WITH SAID FLUID, THE FLUID OF SAID RECEIVING VESSEL BEING BELOW THE DISCHARGE MEANS OF SAID FLUID TRAP, FIRST CONDUIT MEANS DIRECTLY CONNECTING SAID DISCHARGE MEANS TO SAID RECEIVING VESSEL, AND SECOND CONDUIT MEANS CONNECTED TO SAID FIRST CONDUIT MEANS AT THE HIGH POINT THEREOF AND EXTERNAL OF SAID JACKET AND CONNECTED TO SAID TANK ABOVE THE LIQUID LEVEL THEREOF VENTING SAID FIRST CONDUIT MEANS.