Space conserving integrated cryogenic fluid delivery system

An integrated cryogenic fluid delivery system includes a tank adapted to hold a supply of cryogenic liquid and having an end wall. A shroud is positioned on the end wall and contains a shell and tube heat exchanger. The heat exchanger includes a shell defining a warming fluid chamber and having a shell inlet and a shell outlet in fluid communication with the warming fluid chamber. A number of cryogenic fluid coils are positioned within the warming fluid chamber and are in fluid communication with a cryogenic fluid inlet port and a cryogenic fluid outlet port. A fuel shutoff valve has an inlet in fluid communication with a liquid side of the tank and an outlet in fluid communication with the cryogenic fluid inlet port of the heat exchanger. A manual vent valve has an inlet in fluid communication with a headspace of the tank and an outlet. The fuel shutoff valve and the manual vent valve each have a control knob that is accessible from the first or second side of the shroud.

FIELD OF THE INVENTION

The present disclosure relates generally to cryogenic fluid delivery systems and, more specifically, to a space conserving integrated cryogenic fluid delivery system.

BACKGROUND

Cryogenic fluid delivery systems must often be installed in environments that have considerable space limitations. For example, the components of a system for providing liquid natural gas (LNG) to the engine of an LNG-powered vehicle must be mounted on the chassis of the vehicle, along with the LNG storage tank. As a result, it is often desirable to integrate all of the components of the system, an example of which is provided inFIG. 1, into one assembly. The assembly of components may be positioned within in a shroud, indicated at5inFIG. 1, which may be attached to an end wall or head of the tank containing the LNG, as taught in commonly assigned U.S. Patent Application Publication No. US 2014/0223924, the contents of which are hereby incorporated by reference.

The prior art system ofFIG. 1includes a cryogenic tank6containing a cryogenic product, such as LNG. A pressure gauge12and level gauging system8indicate the status of the cryogenic product in the tank. A fill receptacle10is provided to fill the tank and a check valve11is provided to prevent back flow. More specifically, during filling, LNG enters receptacle10, travels through the check valve11and up fill line16to exit into the head space of the tank6.

Pressure relief devices, such as valves17and19are used to avoid over-pressurization of the tank6. Vent valve20in conjunction with vent receptacle14allow the tank to be depressurized if needed for fueling or maintenance purposes.

A fuel pickup line18has a bottom opening in communication with the liquid in the bottom of the tank6. In normal use of the system, that is, during dispensing or delivery of vaporized LNG, liquid or fuel shutoff valve22is open, while manual vent valve20is closed. To dispense LNG, or deliver it to the vehicle engine or other use device, automatic delivery valve24is opened. Due to the pressure in the head space of the tank, when valve24is opened, the LNG travels up line18and through line26, including through valve22. The LNG then travels through vaporizer28which vaporizes the LNG to a vapor phase, which then flows to the use device through valve24.

One or more features are in place in case of fuel line breakage or rupture. Excess flow valve30may be in place to directly sense a flow of LNG though line26that exceeds normal operational characteristics at which point the valve30closes. Alternatively or in conjunction with the aforementioned feature, low temperature switch32can sense the fuel temperature downstream of vaporizer28and may signal the closure of automatic valve24if necessary. This latter protection protects against failures such as fuel line breakage between the tank6and the use device and against failures of the vaporizer28itself including insufficient heat exchange fluid flow-both conditions resulting in cold fuel temperature downstream of the heat exchanger.

A delivery pressure regulator34may be used to limit pressure delivery of the gas to the use device if the maximum allowable pressure of the use device exceeds the pressure setting of the primary relief valve17.

Depending upon the system pressure, vapor may be withdrawn from tank6through economizer regulator36which is connected to fuel pickup line18through line38and communicates with the head space of the tank through lines40and42. When the vapor pressure in the tank head space exceeds a predetermined level, economizer regulator36opens so that vapor from the head space travels through lines42,40and38to lines18and26, and ultimately out of the tank through regulator34.

While, as indicated above, manual vent valve20is typically closed, it may be opened during filling to reduce pressure or vent gas back to the fueling station. Manual liquid or fuel shutoff valve22may be closed for maintenance purposes.

Prior art systems that feature the components ofFIG. 1typically position the manual vent valve20and the fuel shutoff valve22so that the face the open rear or back of the shroud5.

There continues to be a desire to develop cryogenic fluid delivery systems with increased space efficiency, valve accessibility and ease of system installation.

SUMMARY

In one aspect, an integrated cryogenic fluid delivery system includes a tank adapted to hold a supply of cryogenic liquid and having an end wall. A shroud is positioned on the end wall and has a first side, a second side and a bottom wall. A shell and tube heat exchanger is positioned in the shroud and includes a shell defining a warming fluid chamber. The shell has a shell inlet and a shell outlet in fluid communication with the warming fluid chamber. A number of cryogenic fluid coils are positioned within the warming fluid chamber and are in fluid communication with a cryogenic fluid inlet port and a cryogenic fluid outlet port. A fuel shutoff valve has an inlet in fluid communication with a liquid side of the tank and an outlet in fluid communication with the cryogenic fluid inlet port of the heat exchanger. A manual vent valve has an inlet in fluid communication with a headspace of the tank and an outlet. The fuel shutoff valve and the manual vent valve each have a control knob that is accessible from the first or second side of the shroud.

DETAILED DESCRIPTION OF EMBODIMENTS

The embodiments of the system of the disclosure described below provide an integrated delivery system of liquefied natural gas (LNG) from a storage tank to a use device, such as a natural gas powered vehicle engine. It is to be understood that the invention may alternatively be used to deliver or dispense other types of cryogenic fluids.

An embodiment of the integrated cryogenic fluid dispensing system of the disclosure is indicated in general at10inFIGS. 2-4. The system includes a shroud12which may include a generally flat bottom wall14. The shroud is preferably mounted to the end wall or head of a tank15, and may have a top with a curvature that matches the curvature of the tank top and sidewalls.

A heat exchanger16is mounted upon the bottom wall, such as by U-bolts18aand18b. Other arrangements known in the art may be used to secure the heat exchanger16within the shroud12, and other mounting locations within the shroud may be chosen.

As illustrated inFIGS. 2 and 3, the shroud may be provided with an opening26through which vertical fitting panels30and32extend. A number of fittings are mounted within the fitting panels30and32, the functionality of which will be explained below. Such a mounting arrangement permits the fittings to be easily accessed during installation of the tank and system within a vehicle or other environment with limited space.

The heat exchanger16is preferably a shell and tube heat exchanger where the shell receives a warming fluid, such as the coolant from a vehicle's engine, via shell inlet port24. After passing through the shell, the cooled warming fluid exits the heat exchanger via shell outlet port22. The shell inlet port24is attached to a warming fluid inlet fitting42(FIG. 3) via line44, which may be insulated. The shell outlet port22is similarly attached to a warming fluid outlet fitting34via line36, which also may be insulated. Fittings34and42may be connected to a source of warming fluid, such as the cooling system of a vehicle so that fitting42receives the warming fluid from the vehicle cooling system, and fitting34returns the cooled warming fluid to the vehicle cooling system. As a result, the vehicle coolant circulates through the shell of the heat exchanger16.

It is to be understood that the term “line” as used herein includes any type of piping, tubing or conduit through which a fluid may flow.

With reference toFIG. 2, the heat exchanger16has a cryogenic fluid inlet port46and a cryogenic fluid outlet port48. Line106exits the tank15through knuckle fitting54and is in fluid communication with a liquid side of the tank via a liquid dip tube (such as18inFIG. 1) positioned within the tank. As illustrated inFIGS. 2-4, line106leads to the inlet of a fuel shutoff valve102, which has a control knob104. When fuel shutoff valve102is open, due to the headspace pressure in tank15, LNG travels from the tank, through line106, through the valve102and then through line62and into the heat exchanger via inlet port46, where it is vaporized. The resulting vapor exits the heat exchanger via cryogenic fluid outlet port48(FIG. 2). The exiting fluid flows through lines66and68to fuel outlet fitting72(FIG. 3) of fitting panel30.

An automatic valve (74inFIG. 2) is positioned between lines66and68and communicates, via electrical fitting76(FIGS. 2 and 3), with a low temperature switch (such as32inFIG. 1) that can sense the fuel temperature downstream of the heat exchanger16. If the low temperature switch detects a low fuel temperature, which would indicate, for example, a failure of the heat exchanger16or breakage of the line leading from the system10to the vehicle engine (or other use device), the automatic valve74closes.

An economizer circuit includes a regulator76(FIGS. 2-3) having an inlet that communicates with the headspace of tank15via line52and an outlet that communicates with line78, which in turn communicates with line106. In the event that the pressure in the headspace of tank15exceeds the pressure setting of regulator76, the regulator opens and LNG vapor is supplied from the tank headspace to the line78via line52so that the LNG vapor travels to line106and does not have to be vented. If the pressure within the headspace of the tank15rises to a level that further and immediate venting is required, relief venting valve92opens. When relief venting valve92opens, the vapor from line88(which communicates with the tank headspace) is directed through line84which leads to vent fitting86(FIG. 3) mounted within the venting panel32. As a result, the headspace of the tank is vented through line88when valve92is open without passing through the regulator76. A pressure gage90communicates with line88, and thus the headspace of the tank15, via line93. Line52is also provided with a venting valve82(FIG. 2).

A manual vent valve56(FIG. 3) features a control knob58(FIG. 4). A line55leads from the tank headspace (after passing through knuckle fitting54via line52) to the inlet of the valve56. The outlet of the manual vent valve56communicates with the inlet of a junction108via line112. The junction108features an outlet that communicates with a manual vent fitting114(FIG. 3) via line116. A vent receptacle valve122, using an adapter nozzle, is also in fluid communication with an outlet of junction108. When the manual vent valve56is open, if the pressure in the headspace of tank15is excessive, vent receptacle valve122is actuated.

As illustrated inFIG. 4, fuel shutoff valve control knob104and manual vent valve control knob58are preferably accessible through an opening107formed in the side of the shroud12.

The system may be constructed so that the sides featuring the fitting panels30and32(FIG. 3) and the valve handles58and104(FIG. 4) may be reversed.

With reference toFIG. 3, a tank refill inlet fitting is provided at124. The refill inlet fitting is provided with a junction126(FIG. 4) having a first outlet that communicates with refill line128. As shown inFIG. 2, the refill line128leads to a check valve132. When a source of pressurized LNG is connected to the refill inlet fitting124, LNG flows through line128, through check valve132and fitting54and into the tank15. Junction126features a second outlet that communicates with line134that leads to a vent valve136.

Additional details for the heat exchanger16ofFIGS. 2-4are provided inFIG. 5. As illustrated inFIG. 5, the heat exchanger is a shell and tube heat exchanger with the shell having a cylindrical main body204and end walls or headers206aand206bthat cooperate to define the warming fluid chamber of the heat exchanger, which receives a warming fluid, such as the coolant of the vehicle, through shell inlet port24. As described above, the warming fluid leaves the warming fluid chamber of the shell through shell outlet port22.

A pair of cryogenic fluid coils202aand202b(the tubes of the shell and tube heat exchanger16) are coiled in a parallel fashion and connect at inlet ends to cryogenic fluid inlet port46and at outlet ends to cryogenic fluid outlet port48. As a result, cryogenic fluid from the tank15(ofFIGS. 2-4) travels through the parallel coils202aand202bin parallel flow heat exchange with the warming fluid flowing through the shell warming fluid chamber.

While a pair of cryogenic fluid coils202aand202bare illustrated, the heat exchanger may include an alternative number of coils.

As examples only, the shell (204,206aand206b) is preferably constructed from stainless steel, while the coils202aand202bare also preferably constructed from stainless steel.

The system of the disclosure is particularly suited for users requiring easy assembly and minimal packaging space. Also end users in cold weather climates may benefit.

Embodiments of the system may include components with non-traditional geometry and/or combined functions. The manual vent and fuel shutoff hand valves, by being located to the side of the shroud, provide for easy access, and the valves may be located on either side of the shroud, with both on the same side of the shroud or one on each side of the shroud. In addition, the above embodiments allow the length of the tank to increase in the desired installation location on the vehicle, due to the hand valves being located on the side(s). This results in the ability to provide the user with a larger capacity tank providing increased driving range while still being able to easily access the hand valves. The above embodiments allow for an internal plumbing design that facilitates the location of interface bulkhead fittings that will be used by the user. Locating the fittings on vertical panels allows for direct horizontal piping entry resulting in easier installation of the tank to the vehicle.

While the preferred embodiments of the disclosure have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the disclosure, the scope of which is defined by the following claims.