WO1998016766A1

WO1998016766A1 - Cryogenic fluid process containment valve, method and system

Info

Publication number: WO1998016766A1
Application number: PCT/US1997/018419
Authority: WO
Inventors: John W. Bonn
Original assignee: Process Systems International, Inc.
Priority date: 1996-10-15
Filing date: 1997-10-15
Publication date: 1998-04-23

Abstract

A cryogenic fluid storage system (76) and method is shown for receiving, storing and dispensing cryogenic fluids. The system includes a cryogenic storage tank (78), cryogenic receiving station (80), piping (82) interconnecting the tank and station, and a process containment valve (10) intermediate the station (80) and tank (78). The valve (10) includes an inlet (14) and an outlet (16), a valve plug (20) removably positioned between the inlet (14) and outlet (16) to permit and stop flow of fluid through the valve (10), and an integral, pressure operated check valve (24) for permitting flow of fluid to the tank (78), upon expansion of the fluid in the piping (82) to a certain pressure.

Description

CRYOGENIC FLUID PROCESS CONTAINMENT VALVE, METHOD AND SYSTEM

Cross Reference to Related Applications This Application claims the benefit of U.S. Provisional Application No. 60/028,184, filed on October 15, 1996.

Background of the Invention

The present invention relates to apparatus for transferring cryogenic fluids such as liquid hydrogen, oxygen, fluorine, neon, helium or liquified natural gas (LNG) , and especially relates to a cryogenic fluid storage and dispensing system and method of containing cryogenic fluid in the system. It is well known that storing and transferring cryogenic fluids requires specialized apparatus because such cryogenic fluids as liquified oxygen, hydrogen, nitrogen, argon or LNG must be stored and maintained at extremely low temperatures. For example, LNG is normally stored at temperatures of between -240° Fahrenheit (F.) to - 200° F. (about -150° Celsius (C.) to -130° C) . It is hoped that LNG will someday become an economical, clean and abundant fuel to power conventional vehicles such as trucks and automobiles. Some governments (e.g., California) have already implemented legislation to require a phase-in of use of LNG for such purposes in the near future.

Efficient and safe storage, distribution and use of LNG poses many technical problems inherent to processing such low temperature fluids. For example, a pumped cryogenic fluid system including a storage tank and cryogenic piping for transferring LNG from the tank to a receiving or fueling station must be extremely well insulated to restrict heat input into the fluid. Typically such tanks and pipes are insulated by creation of a static vacuum between an inner line and outer jacket, and the tanks are frequently positioned underground. Some piping, metering, valves and related dispensing apparatus of a receiving station however, must necessarily be exposed to ambient temperatures, and for convenience those devices are generally referred to as ambient temperature piping. Ambient temperature piping is even more common in association with non-pumped cryogenic fluid systems such as those found on-board vehicles, extending for example from a storage tank through fuel lines and/or filters and into a fuel injection system of an engine.

To minimize heat input from the environment into cryogenic piping and thereby into a cryogenic fluid storage tank of a cryogenic fluid storage and dispensing system, it is typically required that an outlet valve of the cryogenic storage tank be closed when the cryogenic fluid system is not being used to dispense or receive cryogenic fluid such as LNG. Similarly, to restrict heat input from ambient temperature piping into the cryogenic piping, it is likewise required that the cryogenic piping be isolated by isolation valves from ambient temperature piping when the system is not in use. The resulting cryogenic piping of the system then has an isolated amount of LNG that will slowly warm up and expand if not removed to a cooled storage tank. Known technology has either installed pressure relief valves that permit raw LNG to escape to the environment whenever the fluid in the cryogenic pipe warms to produce an unsafe pressure, or has included complex, and costly return valves and piping apparatus to return the cryogenic fluid isolated in the cryogenic pipe back to the storage tank.

Both of these solutions give rise to significant problems. First, venting of the LNG is extremely dangerous because it is flammable and most other cryogenic fluids are also environmental hazards if not properly contained. Second, customers are increasingly sensitive to product loss through venting. Third, piping the isolated cryogenic fluid back to the storage tank involves additional valves and control apparatus to perform that task; and fourth, returning the isolated fluid into the tank also increases heat input from the isolated fluid into the fluid stored in the tank.

Accordingly, it is a general object of the present invention to provide a cryogenic fluid system that overcomes deficiencies of prior art cryogenic fluid systems .

It is a more specific object to provide a cryogenic fluid system having a cryogenic fluid process containment valve that minimizes opening of pressure relief valves of cryogenic piping of the system.

It is another specific object to provide a cryogenic fluid process containment valve that allows return of cryogenic fluid isolated in cryogenic piping back into a cryogenic fluid storage tank of the system without exposing the isolated fluid to ambient temperature piping.

It is yet a further object to provide a cryogenic fluid process containment valve that will simplify complicated return valving and piping systems of known systems . It is a further object to provide a method of containing a cryogenic fluid in a system that minimizes heat input into the system and minimizes escape of cryogenic fluid out of the system into the environment.

The above and other advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.

Summary of the Invention

The present invention relates to a cryogenic fluid process containment valve and method of employing such a containment valve in a cryogenic fluid storage and dispensing system to minimize escape of the fluid out of the system and to minimize heat input into the system.

The cryogenic fluid storage and dispensing system is for receiving, storing and dispensing cryogenic fluids such as liquified natural gas (LNG) , and includes a cryogenic storage tank; a cryogenic receiving or fueling station having ambient temperature piping; cryogenic piping that conducts cryogenic fluid between the storage tank and receiving station; and, a process containment valve secured to the cryogenic pipe to control flow of the cryogenic fluid between the tank and the station. The process containment valve includes a valve body having an inlet to receive fluid from the cryogenic storage tank and an outlet in fluid communication with the inlet to pass fluid out of the valve into the cryogenic piping; a valve plug removably positioned between the inlet and outlet to selectively permit flow of fluid through the inlet and outlet when the valve plug is in an open position and to stop flow of fluid through the inlet and outlet when the valve plug is in a closed position; and a one-way, pressure operated check valve in fluid communication with the inlet and outlet, to permit return flow of the fluid, on expansion to a certain pressure of the fluid in the cryogenic piping secured to the outlet, back to the tank whenever the valve plug is in the closed position. In a particular embodiment the check valve is secured within the valve plug.

The process containment valve of the present invention provides isolation of cryogenic fluid within the storage tank from fluid in the cryogenic process piping, and permits a return path for the isolated fluid to vent back to the storage tank through the check valve. This straight forward method of containment of the cryogenic fluid and containment valve solve several problems in a most effective manner. First, the method of containment and containment valve will minimize opening of a pressure relief valve in the cryogenic process piping whenever the containment valve and a cryogenic piping isolation valve are closed to isolate fluid within the cryogenic piping. In such a situation, the containment valve will also allow venting of the isolated cryogenic fluid back to the storage tank without exposing the isolated fluid to ambient temperature piping downstream of the cryogenic isolation valve, thereby reducing heat input into the storage tank. Further, the containment valve will reduce complexity of cryogenic piping systems as compared to traditional prior art methods of handling the trapped, isolated cryogenic fluid within the cryogenic piping, such as external check valves or other pressure regulation apparatus that would control pressure within the cryogenic piping such as by pressure actuated relief devices venting the fluid to the environment or other containment apparatus. The process containment valve will inherently reduce costs of the cryogenic fluid storage and dispensing system by integrating the check valve between the inlet and outlet of the valve body. That feature eliminates difficulties associated with setting relief valve pressures on external valves between an outlet valve and a pressurized cryogenic storage tank of known cryogenic fluid systems.

The process containment valve has many applications for all cryogenic fluids, but is especially beneficial to cryogenic fluids that fall into the following categories: Flammable - methane, hydrogen; Hazardous - fluorine, oxygen; Rare - neon, helium. Inert gases, such as nitrogen and argon, do not necessarily need a process containment valve for most applications, but some customers may be very sensitive to excess product loss and may want such a valve installed in their systems for those cryogenic fluids. A cryogenic storage tank is part of most cryogenic fluid systems, and the process containment valve of the present invention can be set up to return any unused cryogenic product back to the storage tank while minimizing heat input into the system.

Brief Description of the Drawings

Figure 1 is a cross-sectional view of a process containment valve constructed in accordance with the present invention, showing the valve in an open position.

Figure 2 is a cross-sectional view of the Figure 1 process containment valve, showing the valve in a closed position.

Figure 3 is a representative schematic illustration of a first prior art cryogenic fluid system.

Figure 4 is a representative schematic illustration of a second prior art cryogenic fluid system.

Figure 5 is a representative schematic illustration of a cryogenic fluid system employing the process containment valve of the present invention.

Description of the Preferred Embodiments Referring to the drawings in detail, a process containment valve of the present invention is best shown in FIGS. 1 and 2, and is generally designated by the reference numeral 10. As best seen in FIG. 1 wherein the containment valve 10 is shown in an open position, the valve includes a valve body 12 defining an inlet 14 and an outlet 16, and a plug chamber 18 between the inlet and outlet 14 , 16. A valve plug 20 selectively moves between an open position (shown in FIG. 1) , wherein the plug chamber 18 is unobstructed and fluids may readily flow between the inlet 14 and outlet 16, and a closed position (shown in FIG. 2) , wherein the valve plug 20 rests against a plug shoulder 22 within the plug chamber 18 to prohibit movement of fluid between the inlet 14 and outlet 16. The valve plug 20 includes a one-way, pressure operated check valve such as ball check valve 24 having a valve inlet channel 26, a ball orifice 28, and a ball tunnel 30 defined within the plug 20. A spring plate 32 is removably secured to the plug 20 adjacent the ball tunnel 30 to secure a coil spring 34 and ball 36 within the tunnel 30 so that the ball 36 rests against the ball orifice 28 to block passage of fluid through the orifice. The spring plate 32 may be a standard spring tension adjustment means for adjusting tension of the spring against the ball as is well known in the art, such as a helical threaded plate in a corresponding helical threaded bore of the tunnel, so that rotation of the plate 32 changes the tension of the spring against the ball, and hence adjusts a pressure setting of the ball check valve 24 at which the ball 36 will descend into the ball tunnel 30 in response to pressure of a fluid within the valve inlet channel 26. Alternatively, the pressure setting of the ball check valve 24 may be adjusted by changing the coil spring 34 for a spring of a specifically desired tension. Plug by-pass channels 38A, 38B are defined within the valve plug 20 to be in fluid communication with the ball tunnel 30 adjacent the ball orifice whenever the ball 36 is displaced into the ball tunnel 30 and are defined to be obstructed by the ball 36 whenever the ball is seated within the ball orifice 28 by the coiled spring 34, as with standard spring-biased ball check valves. The plug by-pass channels 38A, 38B are dimensioned to permit fluid to flow from the valve channel inlet 26 through the valve plug 20 and out of the valve plug adjacent the spring plate 32 into the plug chamber and adjacent inlet 14 whenever the ball 36 is displaced out of the ball orifice 28.

As best shown in FIG. 2, if a cryogenic fluid located within the outlet 16 of the valve body 12 warms and hence expands to displace the ball 36 into the ball tunnel 30 away from the ball orifice 28, the fluid would then be free to pass through the plug by-pass channels 38A, 38B and valve plug 20 and into the inlet 14 of the valve body.

The process containment valve 10 includes actuating means for moving the valve plug 20 between the open and closed positions that may include any standard valve actuating mechanisms that move a fluid obstructing plug between a fluid inlet and outlet to permit and prohibit fluid flow between the inlet and outlet. The actuating means may include a threaded jacket 40 secured to the valve plug 20 dimensioned to move axially within a threaded sleeve 42 secured to the valve body 12 whenever a guide post 44 of the jacket 40 is rotated by a valve stem 46 rotationally secured to the valve body 12. The valve stem 46 includes a post slot 48 that houses the guide post 44 as the valve plug 20 moves from the closed position of FIG. 2 to the open position of FIG. 3. The actuating means may also include a stem handle 50 defining tool slots 52A, 52B and a mounting nut 54 for mounting an automatic tool (not shown) to the handle 50 to automatically rotate the handle upon receipt of and electrical signal in a well known manner .

The valve stem 46 is rotationally secured within the valve body by a stem coupler 56 in a conventional manner including a snap ring 58 secured to the stem 46 above first and second seal mounts 60, 62 that secure a first "O" ring type of seal between the coupler 56 and the stem to prohibit passage of any fluids between the coupler 56 and stem 46 out of the valve 10. A second "0" ring seal 66 is secured between the coupler 56 and a mounting shoulder 68 of the valve body 12, and a third "0" ring seal 70 is secured between the mounting shoulder and the threaded sleeve 42 of the valve body 12. The stem coupler 56 includes a threaded barrel 72 dimensioned to engage a threaded coupler sleeve 74 of the valve body 12 adjacent the mounting shoulder 68 of the body 12. As is apparent from FIGS. 1 and 2, removal of the snap ring 58 from engagement with the stem, and rotation of the stem coupler 56 away from the valve body 12 readily facilitates removal of the stem 46 from the body, after which the valve plug 20 may be unthreaded out of the threaded sleeve 42 of the body to disassemble the valve 10.

Use of the process containment valve 10 of the present invention within a cryogenic fluid system 76 is shown schematically in FIG. 5, and contrasted with prior art cryogenic fluid systems shown schematically in FIGS. 3 and 4. The cryogenic fluid system may include a cryogenic fluid storage tank 78 for storing a cryogenic fluid 79 such as liquified natural gas (LNG) ; a cryogenic receiving or fueling station 80 including ambient temperature piping for dispensing and receiving cryogenic fluids; cryogenic piping 82 for conducting the cryogenic fluid between the storage tank 78 and receiving station 80, including a cryogenic piping isolation valve 84 for isolating cryogenic fluid within the cryogenic piping 82 from the ambient temperature piping within the receiving station 80; and the process containment valve 10 wherein the outlet 16 is secured in fluid communication with the cryogenic piping 82 and the inlet is secured in fluid communication with the storage tank 78 through a feed line 86 between the storage tank and containment valve 10. The receiving station 80 may be a cryogenic fuel dispensing and/or receiving facility of pumped cryogenic fluid systems, or the station 80 may be any device that uses cryogenic fluid, such as an engine in a vehicle on-board, non-pumped cryogenic fluid system. In such cryogenic systems, it is also common to have a tank pressure release valve 88 that vents the cryogenic fluid out of the tank in the event the fluid reaches unsafe pressures. A method of operation of the cryogenic fluid system 76 of the present invention results in enhanced containment of the cryogenic fluid 79 within the system 76, and reduced heat input into the system from any fluid isolated in the cryogenic piping 82. In that method of operation of the cryogenic fluid system 76 of the present invention, whenever the receiving station 80 is being utilized (for example to dispense LNG to a vehicle) , the containment valve 10 is in an open position as shown in FIG. 1, and the cryogenic fluid flows from the storage tank 78 through the feed line 86, cryogenic piping 82 and into the receiving station 80. Whenever the receiving station ceases operation, the containment valve 10 is adjusted into the closed position shown in FIG. 2, and the cryogenic piping isolation valve 84 is also closed. The cryogenic piping 82 then contains and isolated amount of cryogenic fluid. Cryogenic piping is typically extremely well insulated, often having a static vacuum established in an insulation chamber between an inner line and outer jacket to minimize heat input by conduction or convection, and also including reflective sheet material such as aluminized mylar to minimize heat input by radiation. Consequently, the isolated cryogenic fluid may remain in the cryogenic piping for some time before heating and therefore expanding.

During operation of the cryogenic fluid system 76, the ball check valve 24 of the containment valve 10 may have its spring 34 adjusted to apply a very specific pressure on the ball 36 holding it against the ball orifice 28 and hence securing the check valve 24 closed. For example, the spring 34 may be adjusted or pre-set to exert a pressure on the ball 36 that is as little as 1 - 2 p.s.i.g. greater than the pressure exerted on the ball 36 by the cryogenic fluid stored in the cryogenic storage tank 78. Consequently, if the isolated cryogenic fluid within the cryogenic piping warms to the point that it exerts a greater pressure on the ball 36 than the pressure of the stored cryogenic fluid, the ball 36 will be displaced into the ball tunnel 30, and the isolated cryogenic fluid will then pass by the pressure differential through the plug bypass channels 38A, 38B into the inlet 14 of the valve 10 and back into the storage tank 78. As is apparent, because the ball check valve 24 can be adjusted to open upon a slightly higher pressure of the isolated cryogenic fluid in the cryogenic piping 82, the isolated fluid may thereby be vented back into the storage tank 78 almost immediately upon any increase in temperature (and hence pressure) relative to a temperature of the stored cryogenic fluid in the storage tank 78. Therefore, the isolated cryogenic fluid may be returned back to the storage tank with the least possible heat input from the environment around the cryogenic piping 82. For convenience and enhanced efficiency, a cryogenic return pipe 90 between the cryogenic piping 82 and the outlet 16 of the valve 10 may facilitate return of the isolated cryogenic fluid within the cryogenic piping 82 to the process containment valve. In contrast, a first prior art cryogenic fluid system 92 of traditional design is shown schematically in FIG. 3, and has some similar components to the system 76 of the present invention (those similar components being designated as a prime of the reference numerals of the similar components in the cryogenic fluid system 76 of the present invention) . The first prior art cryogenic fluid system includes a cryogenic storage tank 78', a cryogenic receiving station 80', cryogenic piping 82' for conducting fluid between the tank 78' and station 80', a cryogenic piping isolation valve 84', a tank pressure release valve 88' secured to the tank, a first tank outlet valve 94 secured to a tank feed line 86', and a cryogenic piping pressure release valve 96 secured to the cryogenic piping 82'. In operation of the first prior art cryogenic fluid system 92, once the receiving station 80' stops being used, the fist tank outlet valve 94' and the cryogenic piping isolation valve 84' are closed, so that an amount of cryogenic fluid remains isolated within the cryogenic piping 82'. As that isolated cryogenic fluid warms it expands to be vented out of the system 92 by way of the cryogenic piping pressure release valve 96 into the environment or some other containment apparatus (not shown) . The cryogenic fluid passing out of the pressure release valve 96 is then lost to the customer and may also present an environmental hazard.

A known effort to avoid such a result is seen in a second prior art cryogenic fluid system 98 shown in FIG. 4 (wherein similar components to those in the first prior art system 92 are designated as a double prime of the reference numerals found in FIGS. 3 and 5) . The second prior art cryogenic fluid system includes a cryogenic storage tank 78'', a cryogenic receiving station 80'', cryogenic piping 82'' for conducting fluid between the tank 78'' and station 80'', a cryogenic piping isolation valve 84'', a tank pressure release valve 88'' secured to the tank 78'', a second tank outlet valve 99 secured to a tank feed line 86'', and a cryogenic back flow-loop 100 including a back- flow check valve 102 of conventional design, the loop 100 being secured between upstream and downstream sides of the second outlet valve 99.

In operation of the second prior art cryogenic fluid system 97, once the receiving station 80'' ceases operation, the second tank outlet and cryogenic pipe isolation valves 99, 84'' are closed leaving an amount of cryogenic fluid isolated in the cryogenic pipe 82''. When the isolated fluid warms and expands, the back flow-check valve 102 opens to permit the fluid to return to the storage tank 78''. As is apparent, however, the second prior art cryogenic fluid system 98 requires additional cryogenic piping for the back flow-loop 100, and the back- flow check valve 102 may not be set with the same sensitivity as the ball check valve 24 of the process containment valve 10 because the back flow-check valve 102 is always exposed to downstream pressure of the cryogenic fluid within the cryogenic piping 82'' as well as pressure characteristics of the back-flow loop 100 during usage of the receiving station 80''. During usage of any fluid containment system, whenever a downstream demand is changed or terminated, it is common to generate pressure pulses and/or pressure waves that rapidly travel upstream of the demand, such as the receiving station 80''. Such a pressure wave could have the effect of opening the back- flow check valve 102 prematurely, because it is exposed to the pressure of the cryogenic fluid even when the second outlet valve 99 is open in contrast to the ball check valve 24 positioned within the valve plug 20 of the present invention. Therefore, pressure settings of the back-flow check valve 102 cannot be as sensitive as the ball check valve 24. Consequently, while the second prior art cryogenic fluid system 98 solves some of the problems of the first prior art system 92, it requires additional complex piping and valving, and requires a substantial pressure differential for efficient return of isolated cryogenic fluid to the storage tank 78'' and therefore exposes the stored cryogenic fluid 79'' in the tank 78'' to a greater heat input than the cryogenic fluid system of 76 of the present invention.

It is noted that the process containment valve 10 of the present invention may be a containment valve means for controlling flow of cryogenic fluid from the storage tank 78 through the inlet 14 and outlet 16 of the valve body to the receiving station 80, including an integral one-way, pressure operated check valve means in fluid communication with the inlet 14 and outlet 16 for permitting flow of fluid to the storage tank, on expansion to a certain pressure of the fluid in the outlet 16. For example, while the illustrated embodiment of the process containment valve 10 shows the ball check valve 24 secured within the valve plug 20 so that it is only operational when the valve plug is in a closed position, the containment valve 10 includes alternative embodiments wherein a one-way, pressure operated check valve is positioned in fluid communication with the inlet and outlet 14, 16, such as within a throughbore (not shown) defined within the valve body passing between the inlet and outlet 14, 16.

The cryogenic fluid system 76 and process containment valve 10 of the present invention may be fabricated of standard materials well known in the art for making cryogenic fluid systems and stem valves for controlling flow of cryogenic fluids.

While the present invention has been described and illustrated with respect to a particular construction and method of operation of a cryogenic fluid system utilizing a process containment valve, it will be understood by those skilled in the art that the present invention is not limited to the described and illustrated examples. Accordingly, reference should be made primarily to the attached claims rather than the foregoing description to determine the scope of the invention.

Claims

CLAIMSWhat is claimed is:

1. A cryogenic fluid system, comprising: a. a cryogenic fluid storage tank; b. a cryogenic fluid receiving station; c. piping for conducting cryogenic fluid between the storage tank and receiving station; and, d. containment valve means for controlling flow of the cryogenic fluid between the storage tank and the receiving station, the containment valve means including an integral one-way, pressure operated check valve means for permitting flow of fluid to the storage tank, on expansion to a certain pressure of the fluid between the valve means and the station.

2. The system of Claim 1, wherein the containment valve means operates between an open position to permit flow of cryogenic fluid and a closed position to stop flow of cryogenic fluid.

3. The system of Claim 1, wherein the containment valve means includes a valve body having an inlet for receiving cryogenic fluid from the storage tank and an outlet in fluid communication with the inlet to pass fluid out of the valve, and the check valve means is in fluid communication with the inlet and outlet.

4. The system of Claim 3 , wherein the containment valve means includes a valve plug removably positioned between the inlet and outlet to selectively permit flow of the cryogenic fluid between the inlet and outlet when the plug is in an open position and stop flow of fluid between the inlet and outlet when the plug is in a closed position.

5. The system of Claim 4, wherein the check valve means is secured within the valve plug.

6. The system of Claim 5 , wherein the check valve means comprises a ball check valve including a valve inlet channel, a ball orifice and a ball tunnel defined within the valve plug and in fluid communication with the inlet and outlet, a spring plate adjustably secured to the plug adjacent the ball tunnel, a coil spring and ball adjustably secured by the spring plate within the ball tunnel so that the ball rests against the ball orifice to block passage of fluid through the orifice, and at least one plug by-pass channel within the valve plug defined to be in fluid communication with the outlet and the ball tunnel adjacent the ball orifice whenever the ball is displaced into the ball tunnel away from the ball orifice and defined to be obstructed by the ball whenever the ball is seated in the ball orifice.

7. The system of Claim 1, wherein the piping for conducting the cryogenic fluid is cryogenic piping.

8. The system of Claim 7, further comprising a cryogenic piping isolation valve secured to the cryogenic piping adjacent the receiving station that operates between an open position to permit flow of fluid between the cryogenic piping and receiving station and a closed position to stop flow of the fluid between the piping and station and isolate cryogenic fluid in the cryogenic piping from ambient temperature piping in the receiving station.

9. A process containment valve for controlling flow of a fluid, comprising: a. a valve body having an inlet to receive fluid and an outlet in fluid communication with the inlet to pass fluid out of the valve; b. a valve plug removably positioned between the inlet and the outlet to selectively control flow of fluid through the inlet and outlet; and c. an integral one-way, pressure operated check valve means in fluid communication with the inlet and outlet for permitting flow of fluid to the inlet, on expansion to a certain pressure of the fluid in the outlet.

10. The process containment valve of Claim 9, wherein the containment valve operates between an open position to permit flow of cryogenic fluid and a closed position to stop flow of cryogenic fluid.

11. The process containment valve of Claim 10, wherein the valve plug is positioned between the inlet and the outlet in the closed position.

12. The process containment valve of Claim 11, wherein the check valve means is secured within the valve plug.

13. The process containment valve of Claim 12, wherein the check valve means comprises a ball check valve including a valve inlet channel, a ball orifice and a ball tunnel defined within the valve plug and in fluid communication with the inlet and outlet, a spring plate adjustably secured to the plug adjacent the ball tunnel, a coil spring and ball adjustably secured by the spring plate within the ball tunnel so that the ball rests against the ball orifice to block passage of fluid through the orifice, and at least one plug by-pass channel within the valve plug defined to be in fluid communication with the outlet and the ball tunnel adjacent the ball orifice whenever the ball is displaced into the ball tunnel away from the ball orifice and defined to be obstructed by the ball whenever the ball is seated in the ball orifice.

14. A method of containing cryogenic fluid in a system, which method comprises the steps of: a. providing a cryogenic fluid storage tank and a cryogenic fluid receiving station; b. connecting the tank to the station with piping; and, c. providing a valve means intermediate the storage tank and receiving station for controlling flow of cryogenic fluid between the tank and station, which valve means includes a process containment valve having an integral, one-way, pressure operated check valve therein, to permit flow of fluid to the storage tank, on expansion to a certain pressure of the fluid between the valve means and the station.

15. The method of Claim 14, comprising a further step of operating the valve means between an open position to permit flow of the cryogenic fluid and a closed position to stop flow of the fluid.

16. The method of Claim 15 wherein the step of providing the valve means further comprises removably positioning a valve plug between an inlet and an outlet of the valve means for selectively operating the valve means between the open and closed positions.

17. The method of Claim 16, further comprising securing the one-way, pressure operated check valve within the plug so that the check valve is in fluid communication with the inlet and the outlet whenever the valve means is in the closed position.