FR3135505A1 - Cryogenic valve and assembly comprising such a valve - Google Patents

Abstract

Cryogenic valve and assembly comprising such a valve The cryogenic valve (23) comprises: - a valve body (27) delimiting a cryogenic fluid passage (33) fluidly connecting a cryogenic fluid inlet (29) to a cryogenic fluid outlet ( 31); - a shutter (37); - an actuator (39); - a kinematic chain (41) via which the actuator (39) moves the shutter (37) between a position for closing the cryogenic fluid passage (33) and a position for clearing the cryogenic fluid passage (33); the valve body (27) further delimiting a heat transfer fluid passage (47) fluidly connecting a heat transfer fluid inlet (43) to a heat transfer fluid outlet (45), the heat transfer fluid passage (47) extending around of the passage of cryogenic fluid (33). Figure for abstract: 2

Description

Cryogenic valve and assembly comprising such a valve

The present invention generally relates to cryogenic valves.

Such a cryogenic valve is typically installed on the outlet conduit of a cryogenic fluid storage unit.

This storage unit can be a tank of liquid hydrogen, intended to supply a fuel cell. The cryogenic valve is interposed between the storage unit and a heat exchanger. The liquid hydrogen is heated in the heat exchanger to a temperature compatible with the operation of the fuel cell.

The storage unit generally includes an internal tank, and an external tank in which the internal tank is housed. Liquid hydrogen is stored inside the internal tank. The intermediate space defined between the internal tank and the external tank is maintained under a high vacuum, so as to provide very effective thermal insulation.

It is possible to design the cryogenic valve with a shutter member arranged on an intermediate portion of the hydrogen outlet conduit, housed in the intermediate space between the internal tank and the external tank. The actuator in this case is located outside the external tank.

Such a cryogenic valve is technically complex and expensive to produce.

In this context, the invention aims to propose a cryogenic valve which is less expensive and above all easier to integrate.

To this end, the invention relates to a cryogenic valve, comprising:
- a valve body delimiting a cryogenic fluid inlet, a cryogenic fluid outlet and a cryogenic fluid passage fluidly connecting the cryogenic fluid inlet to the cryogenic fluid outlet;

- a shutter;

- an actuator;

- a kinematic chain via which the actuator moves the shutter between a position for closing the cryogenic fluid passage and a position for clearing the cryogenic fluid passage;

the valve body further delimiting a heat transfer fluid inlet, a heat transfer fluid outlet and a heat transfer fluid passage fluidly connecting the heat transfer fluid inlet to the heat transfer fluid outlet, the heat transfer fluid passage extending around the passage cryogenic fluid.

Such a cryogenic valve can be placed outside the external tank. Indeed, because the heat transfer fluid passage extends around the cryogenic fluid passage, the surfaces of the valve body in contact with the cryogenic fluid are not directly exposed to the atmosphere surrounding the valve body.

The risk of the air surrounding the valve body being liquefied is therefore eliminated.

In the case where the cryogenic fluid is hydrogen, it is liquid, at ambient pressure, at a temperature close to 20 K.

Air liquefies from -196° C, i.e. around 77 K. Liquid air can, under certain conditions, contain up to 50% oxygen by mass, and is therefore extremely oxidizing. It is imperative that the surfaces of the valve body in contact with the liquid hydrogen are not directly in contact with the ambient air.

This is obtained in the invention by the arrangement in the valve body of a heat transfer fluid passage around the cryogenic fluid passage.

Such a valve body is not excessively expensive to produce.

Furthermore, because the valve body can be placed outside, in the atmosphere surrounding the cryogenic gas storage unit, it is not necessary to move the actuator away from the valve body. As a result, the structure of the valve is simplified and the valve is much less expensive than that of the state of the art.

The valve may also represent one or more of the characteristics below, considered individually or in any technically possible combination:

- the heat transfer fluid outlet is annular and surrounds a downstream end portion of the cryogenic fluid passage ;

- the valve body comes from the foundry, in one piece, the valve body having surfaces in contact with the cryogenic fluid, said surfaces preferably being machined ;

- the valve body has at least one internal partition delimiting on one side the cryogenic fluid passage and on the other side the heat transfer fluid passage, the at least one internal partition having a thickness greater than 2 mm;

- the actuator comprises a drive member, the kinematic chain comprising a rod having a distal end part carrying the shutter, a proximal end part linked to the drive member and an intermediate part engaged in a orifice formed in the at least one internal partition, the cryogenic valve comprising a sealing bellows arranged around the distal end portion, a proximal end of the sealing bellows being sealed in a sealed manner by welding to the member of drive, a distal end of the sealing bellows being sealed by welding to the at least one internal partition, around the orifice.

According to a second aspect, the invention relates to an assembly comprising a cryogenic valve having the above characteristics, and a heat exchanger having a cryogenic fluid circulation side and a heat transfer fluid circulation side, the circulation side of cryogenic fluid having a cryogenic fluid exchanger inlet, connected to the cryogenic fluid outlet of the cryogenic valve, the heat transfer fluid circulation side having a heat transfer fluid exchanger inlet, connected to the heat transfer fluid outlet of the cryogenic valve .

This set may also represent one or more of the characteristics below, considered individually or in all technically possible combinations:

- the heat exchanger comprises an exchanger flange in which the cryogenic fluid exchanger inlet and the heat transfer fluid exchanger inlet are arranged, the heat transfer fluid exchanger inlet being annular and surrounding the heat exchanger cryogenic fluid exchanger inlet, the cryogenic valve and comprising a valve flange fixed to the exchanger flange in which the cryogenic fluid outlet and the heat transfer fluid outlet are provided;

- the valve flange and the exchanger flange are in contact with each other along a contact zone having a portion separating the cryogenic fluid exchanger inlet from the cryogenic fluid exchanger inlet heat transfer fluid and also separating the cryogenic fluid outlet from the heat transfer fluid outlet, one of the valve flange and the exchanger flange comprising a channel fluidly connecting said portion with the outside, the assembly further comprising :

- a first seal interposed between said portion on the one hand and on the other hand the cryogenic fluid outlet and the cryogenic fluid exchanger inlet;

- a second seal interposed between said portion on the one hand and on the other hand the heat transfer fluid outlet and the heat transfer fluid exchanger inlet ;

- the cryogenic fluid circulation side comprises a single tube, made from material, having an upstream end welded to the exchanger flange ;

- the assembly comprises a cryogenic fluid storage unit with an internal reservoir internally delimiting a volume for receiving cryogenic fluid, an external reservoir in which the internal reservoir is housed, and a conduit fluidly connecting the cryogenic fluid inlet of the cryogenic valve to the receiving volume, the cryogenic valve being arranged outside the external tank .

Other characteristics and advantages of the invention will emerge from the detailed description given below, for information only and in no way limiting, with reference to the appended figures, among which:

- There is a simplified schematic representation of an assembly according to the invention, powering a fuel cell, the assembly comprising a liquid hydrogen storage unit, a cryogenic valve and a heat exchanger;

- There is a sectional view of the valve of the , the flange of the heat exchanger also being shown;

- There is a perspective view of the valve of the ;

- There is a perspective view of part of the heat exchanger of the .

Set 1, shown on the , is intended to power a fuel cell 3.

The assembly 1 and the fuel cell 3 are typically intended to be on board a vehicle having an electric propulsion motor, for example a motor vehicle, a train, a boat or any other vehicle. The motor vehicle is for example a car, a utility vehicle, a truck, etc.

The fuel cell 3 is configured to produce electricity and power the electric propulsion motor.

The fuel cell 3 includes an anode gas circuit 9 and a cell cooling circuit 11. The fuel cell 3 also includes a cathode gas circuit, not shown.

The anode gas circuit 9 is supplied, by assembly 1, with dihydrogen, commonly called hydrogen. The cathode gas circuit is supplied with oxidizing gas, this oxidizing gas typically being dioxygen contained in the air, commonly called air oxygen or oxygen.

As visible on the , assembly 1 comprises a cryogenic fluid storage unit 12, with an internal reservoir 13 internally delimiting a volume 15 for receiving cryogenic fluid, and an external reservoir 17 in which the internal reservoir 13 is housed.

By cryogenic fluid we mean a fluid at a very low temperature, which is at least partially in the liquid state inside the storage unit. This fluid is typically hydrogen, preferably gaseous hydrogen. Alternatively, the fluid is helium, nitrogen, a natural gas such as methane CH4 from the air, or any other suitable fluid.

An intermediate space 19 separates the internal reservoir 13 from the external reservoir 17.

Thermal insulation 21 is interposed between the internal tank 13 and the external tank 17. The intermediate space 19 is maintained under a high vacuum, typically of the order of 10 ^{- 5} millibars, so as to strongly limit heat transfer by convection from the external tank 17 towards the internal tank 13.

The storage unit 12 is arranged to store liquid hydrogen.

Set 1 also includes a cryogenic valve 23 and a heat exchanger 25.

The cryogenic valve 23 is arranged outside the external tank 17.

As visible on the , the cryogenic valve 23 includes:

- a valve body 27 delimiting a cryogenic fluid inlet 29, a cryogenic fluid outlet 31 and a cryogenic fluid passage 33 fluidly connecting the cryogenic fluid inlet 29 to the cryogenic fluid outlet 31;

- a shutter 37;

- an actuator 39;

- a kinematic chain 41 via which the actuator 39 moves the shutter 37 between a position for closing the cryogenic fluid passage 33 and a position for clearing the cryogenic fluid passage 33.

The valve body 27 further delimits a heat transfer fluid inlet 43, visible on the , a heat transfer fluid outlet 45 and a heat transfer fluid passage 47 fluidly connecting the heat transfer fluid inlet 43 to the heat transfer fluid outlet 45.

The heat transfer fluid passage 47 extends around the cryogenic fluid passage 33.

More precisely, the heat transfer fluid passage 47 extends over the entire periphery of the cryogenic fluid passage 33.

In other words, the cryogenic fluid passage 33 is delimited by partitions 49 of the valve body 27. These partitions 49 are internal partitions. The internal partitions 49 delimit on a first side the cryogenic fluid passage 33 and on a second side, opposite the first side, the heat transfer fluid passage 47. The internal partitions 49 delimiting the cryogenic fluid passage 33 are never in contact with the external atmosphere.

The heat transfer fluid passage 47 extends practically over the entire length of the cryogenic fluid passage 33.

More precisely, as illustrated in the , the heat transfer fluid passage 47 extends over the entire length of the cryogenic fluid passage 33 with the exception of the downstream end portion 51 of the cryogenic fluid passage 33.

In the present description, the terms “upstream” and “downstream” are understood relative to the direction of circulation of the fluid, here the cryogenic fluid.

The downstream end portion 51 of the cryogenic fluid passage 33 is engaged inside the heat exchanger 25, and its outer surface is not in contact with the external atmosphere.

Thus, if the cryogenic fluid passage 33 has a first given developed length, then the heat transfer fluid passage 47 extends along a portion of the cryogenic fluid passage 33 having a second developed length greater than at least 75% of the first developed length.

The valve body 27, as visible on the , has a valve flange 53, provided for attachment to the heat exchanger 25.

The downstream end portion 51 of the cryogenic fluid passage 33 is located in the center of the valve flange 53, and protrudes relative to the valve flange 53.

The valve flange 53 has a flat bearing surface 54 designed to bear against a corresponding surface of the heat exchanger 25. The downstream end portion 51 projects relative to the bearing surface 54. .

The heat transfer fluid outlet 45 is annular, and surrounds the downstream end portion 51.

Material bridges 55 connect the radially outer edge of the heat transfer fluid outlet 45 to the downstream end portion 51 of the cryogenic fluid passage 33. These material bridges 55 divide the heat transfer fluid outlet 45 into several annular sectors.

The cryogenic fluid passage 33 comprises a first rectilinear section 57 extending in a first direction first direction

The second section 59 extends from the first section 57 to the cryogenic fluid outlet 31. The downstream end portion 51 constitutes one end of the second section 59.

The valve flange 53 is substantially perpendicular to the second direction Y.

The cryogenic fluid inlet 29 opens in a lower face 61 of the valve body 27.

This lower face 61 is substantially perpendicular to the first direction X.

It is designed to be mounted in support against the external surface of the external tank 17.

The lower face 61 of the valve body 27 carries a circular rib 63 extending around the cryogenic fluid inlet 29.

The surface 65 of the lower face 61, surrounding the inlet 29, constitutes the seat of the cryogenic valve 23. The shutter 37, in its closed position, rests against this surface 65.

The cryogenic valve 23 also includes a cover 67 attached to an upper face 69 of the valve body 27. The upper face 69 delimits the valve body 27 opposite the lower face 61, in the first direction X.

The cover 67 internally delimits an internal volume 71 communicating with the passage of heat transfer fluid 33 through an opening 73 formed in the upper face 69 of the valve body 27.

Actuator 39 is mounted on cover 67.

The actuator 39, in the example shown, is of the pneumatic type.

It includes a drive member 75, movable in the first direction X.

This drive member 75 comprises a collar 77, substantially perpendicular to the first direction actuator 39.

The actuator 39 also includes an internal membrane 81, arranged inside the body 80 of the actuator 39, and capable of pressing on the lug 79 to move the shutter 37.

The kinematic chain 41 comprises a rod 83 having a distal end portion 85 carrying the obturator 37.

The rod 83 also includes a proximal end portion 87, linked to the drive member 75.

In the example shown, the proximal end portion 87 is linked to the drive member 75 by a sleeve 88.

An intermediate part of the rod 83 is engaged in an orifice 89 formed in the internal partition 49 of the valve body 27. The orifice 89 is a passage delimited by a cylindrical barrel 90 of the internal partition 49 of the valve body 27.

The orifice 89 has a section substantially matched to the section of the intermediate part of the rod 83, and guides the rod 83 in translation.

The rod 83 extends in the first direction X, and moves in this first direction X.

As explained above, in its closed position, the shutter 37 rests against the seat 65 of the cryogenic valve 23. In its release position, the shutter 37 is raised and no longer rests against the seat 65 of the cryogenic valve 23. It is offset towards the outside of the cryogenic fluid passage 33, that is to say towards the bottom of the .

In the shutter position, the support of the shutter 37 on its seat 65 limits the travel of the kinematic chain 41 which is mobile. In the release position, the collar 77 is offset away from the bottom of the cover 67, in the first direction X, towards the cryogenic fluid inlet 29.

The cryogenic valve 23 also includes a return spring 91, returning the shutter 37 to its shutter position.

In the example shown, this return spring 91 is a helical compression spring, coaxial with the first direction internal 49, around the barrel 90.

The cryogenic valve 23 further comprises a sealing bellows 93 arranged around the distal end portion 87 of the rod 83. A proximal end 95 of the sealing bellows 93 is sealed in a sealed manner by welding to the sealing member. drive 75. A distal end 97 of the sealing bellows 93 is sealed by welding to the internal partition 49 of the valve body 27, around the orifice 89.

More precisely, the proximal end 95 of the sealing bellows 93 is welded in a sealed manner to a washer 99, itself welded in a sealed manner to the flange 77 of the drive member 75 of the actuator 39.

The distal end 97 of the sealing bellows 93 is welded in a sealed manner to another washer 101, itself welded in a sealed manner to the internal partition 49 of the valve body 27.

The sealing bellows 93 and the return spring 91 are partly housed in the internal volume 71 of the cover 67.

The heat exchanger 25 comprises a cryogenic fluid circulation side 103 and a heat transfer fluid circulation side 105 ( ). The cryogenic fluid circulation side 103 has a cryogenic fluid exchanger inlet 107, connected to the cryogenic fluid outlet 31 of the cryogenic valve 23. The heat transfer fluid circulation side 105 has a heat transfer fluid exchanger inlet 109, connected to the heat transfer fluid outlet 45 of the cryogenic valve 23.

As clearly visible on the , the heat exchanger 25 comprises an exchanger flange 111, in which the cryogenic fluid exchanger inlet 107 and the heat transfer fluid exchanger inlet 109 are provided.

The heat transfer fluid exchanger inlet 109 is annular and surrounds the cryogenic fluid exchanger inlet 107.

Material bridges 113 connect a radially outer edge of the heat transfer fluid exchanger inlet 109 to the outer surface of the cryogenic fluid exchanger inlet 107. These material bridges 113 divide the heat exchanger inlet 107. heat transfer fluid 109 in several annular sectors.

Valve flange 53 is fixed to exchanger flange 111.

The valve 53 and exchanger 111 flanges are fixed to each other in a removable manner, by fixing members such as screws or tie rods, engaged in orifices of the valve 53 and exchanger 111 flanges. .

The fixing elements are not shown in the figures.

When the valve 53 and exchanger 111 flanges are fixed to each other, the downstream end part 51 is engaged inside the cryogenic fluid exchanger inlet 107 (see ). The heat transfer fluid outlet 45 is placed exactly in coincidence with the heat transfer fluid exchanger inlet 109.

In this situation, the valve flange 53 and the exchanger flange 111 are in contact with each other along a contact zone 115. The contact zone 115 has a portion 117 which separates the inlet cryogenic fluid exchanger 107 from the heat transfer fluid exchanger inlet 109, and which also separates the cryogenic fluid outlet 31 from the heat transfer fluid outlet 45.

In the example shown, portion 117 corresponds to a zone of the external surface of the end part 51, in contact with a zone of the internal surface of the cryogenic fluid exchanger inlet 107.

Furthermore, the exchanger flange 111 has a channel 119 fluidly connecting the portion 117 to the exterior.

A first seal 121 is interposed between on the one hand the portion 117 and on the other hand the cryogenic fluid outlet 31 and the cryogenic fluid exchanger inlet 107.

In other words, the seal 121 isolates the portion 117 of the cryogenic fluid circulating from the cryogenic fluid outlet 31 to the cryogenic fluid exchanger inlet 107.

A second seal 123 is interposed between the portion 117 on the one hand and the heat transfer fluid outlet 45 and the heat transfer fluid exchanger inlet 109 on the other.

In other words, the seal 123 isolates the portion 117 of the heat transfer fluid circulating from the heat transfer fluid outlet 45 to the heat transfer fluid exchanger inlet 109.

Typically, portion 117 carries a groove 125, arranged between seals 121 and 123. Channel 119 opens into groove 125.

The contact zone 115 also carries a third seal 127, interposed between on the one hand the heat transfer fluid outlet 45 and the heat transfer fluid exchanger inlet 109 and on the other hand the external atmosphere.

The third seal 127 prevents leaks of heat transfer fluid to the outside. The first and second seals 121, 123 prevent leaks from the cryogenic fluid circuit to the heat transfer fluid circuit.

In the heat exchanger 25, the cryogenic fluid circulation side 103 comprises a single tube 129, made from material. The tube 129 has an upstream end 131 welded in a sealed manner to the exchanger flange 111. The cryogenic fluid exchanger inlet 107 opens into the tube 129 ( ). The tube 129 is bent in an S shape in the example shown.

The heat transfer fluid circulation side 105 comprises an envelope 133, delimiting an internal volume in which the tube 129 is housed. The heat transfer fluid circulates inside the envelope 133. The exchanger flange 111 is rigidly fixed to the envelope 133. The heat transfer fluid exchanger inlet 109 opens into the internal volume of the envelope 133.

Advantageously, the valve body 27 comes from the foundry.

In other words, the valve body 27 is in one piece. It is in one piece, the cryogenic fluid passage 33 and the heat transfer fluid passage 47 being obtained directly when the valve body 27 is obtained in the foundry.

Advantageously, the valve body 27 is made of 316L type stainless steel. This metal has particularly suitable thermal characteristics. It has a thermal conductivity of between 2 and 4 W/m.K at 20 K. This makes it possible to have a significant temperature gradient at the level of the internal partitions 49, which separate the cryogenic fluid passage 33 from the heat transfer fluid passage 47.

Advantageously, each partition 49 has a thickness greater than 2 millimeters. Such a thickness also contributes to obtaining a significant temperature gradient between the cryogenic fluid passage 33 and the heat transfer fluid passage 47. Typically, the thickness of the internal partition 49 is between 3 millimeters and 8 millimeters, depending on the location.

For example, in the case of a fuel cell 3 producing 110 kW, the flow rate of hydrogen through the cryogenic valve 23 is of the order of 7 g/s, the hydrogen being at 20 K. The flow rate of heat transfer fluid is then 40 l/min. The internal skin temperature, that is to say the temperature at the level of the internal partition 49 on the side of the cryogenic fluid passage 33, is between -100°C and -50°C. The parts of the valve body 27 in contact with the heat transfer fluid are at temperatures which vary between -10°C and 5°C. This is compatible with the use of brine as a heat transfer fluid.

The surfaces of the valve body 27 in contact with the cryogenic fluid are machined to eliminate foundry residue. Indeed, the surfaces of a part coming from the foundry can carry detachable residues, but also pollutants such as oil or solvents.

The surfaces of the valve body 27 are machined in the sense that a thin layer of these surfaces is removed, by means of a machining tool, typically a milling machine. This machining is not intended to modify the shape of the valve body 27, this shape being obtained at the foundry stage.

The machined surfaces include port 89, and the internal surface of cryogenic fluid passage 33.

The lower face 61 of the valve body 27 is also machined, because it defines the seat 65 of the cryogenic valve 23. It is in contact with seals 137, carried by the shutter 37.

Likewise, the upper face 69 of the valve body 27 is machined, because it is in contact with the seal 139 ensuring the seal between the cover 67 and the valve body 27.

The surface of the valve body 27 delimiting the contact zone 115 is also machined, because it carries the seals 121, 123 and 127.

Set 1 also includes a heat transfer fluid circuit 141 ( ).

The heat transfer fluid is typically water containing an antifreeze, typically glycol.

The heat transfer fluid circuit 141, as illustrated on the , comprises an expansion tank 143, having an expansion tank outlet 145 and an expansion tank inlet 147. The battery cooling circuit 11 has a cooling inlet 149 and a cooling outlet 151 The expansion tank inlet 147 is fluidly connected to the cooling outlet 151.

The heat transfer fluid circuit 141 also comprises a heat transfer fluid circulation member 153 having a suction 155 fluidly connected to the outlet of the expansion tank 145, and a discharge 157 fluidly connected to the heat transfer fluid inlet 43 of the cryogenic valve 23.

The heat transfer fluid circulation member 153 is typically a pump, of any suitable type.

The heat transfer fluid circuit 141 also includes an orientation member 159 having an inlet 161 fluidly connected to a heat transfer fluid exchanger outlet 163 of the heat exchanger 25. The orientation member 159 also includes a first outlet 165 fluidly connected to the expansion tank inlet 147. It also includes a second outlet 167 fluidly connected to the cooling inlet 149 of the battery cooling circuit 11.

The orientation member 159 is configured to fluidly connect the inlet 161 selectively to the first outlet 165 or to the second outlet 167.

The orientation member 159 is typically a 3-way valve.

Furthermore, the heat exchanger 25 has a cryogenic fluid exchanger outlet 169. This outlet corresponds to the downstream end of the tube 129.

The cryogenic gas exchanger outlet 169 is fluidly connected to an anode gas inlet 171 of the anode gas circuit 9 of the fuel cell 3. This anode gas circuit 9 has an anodic gas outlet not shown. Optionally, a valve 173 is inserted between the cryogenic gas exchanger outlet 169 and the anode gas inlet 171.

As illustrated on the , a conduit 175 fluidly connects the cryogenic gas inlet 29 of the cryogenic valve 23 to the receiving volume 15 of the cryogenic gas storage unit 12.

The assembly 1 also includes a controller 177. The controller 177 controls the cryogenic valve 23, the orientation member 159, the circulation member 153 and possibly the valve 173, depending on information received from the computer(s). s) on board the vehicle.

The operation of set 1 will now be detailed.

When the fuel cell 3 is in operation, the controller 177 commands the cryogenic valve 23 to place the shutter 37 in its release position.

The actuator 39, via the membrane 81, pushes the drive member 75 in the first direction X towards the cryogenic gas inlet 29. The drive member 75 in turn pushes the rod 83, which raises the shutter 37. The return spring 91 and the sealing bellows 93 are compressed. The cryogenic gas can then flow from the internal volume 15 of the cryogenic fluid storage unit 12 into the cryogenic gas passage 33, then to the cryogenic fluid circulation side 103 of the heat exchanger 25.

The cryogenic gas is at a temperature of approximately 20K in the cryogenic fluid storage unit 12. It is heated to a temperature of approximately 0°C in the heat exchanger. The cryogenic gas then circulates to inlet 171 of the anode gas circuit of the fuel cell.

The controller 177 also keeps the circulation member 153 in operation, and commands the orientation member 159 to put the input 161 in communication with the second output 167.

The circulation member 153 therefore delivers the heat transfer fluid from the expansion tank 143 to the heat transfer fluid inlet 43 of the cryogenic valve 23. The heat transfer fluid circulates along the heat transfer fluid passage 47 up to the heat transfer fluid outlet 45.

The heat transfer fluid fills in particular the internal volume 71 of the cover 67, maintaining the sealing bellows 93 at a moderate temperature. The volume located inside the sealing bellows 93 is filled by the cryogenic fluid, through the orifice 89. However, the circulation of cryogenic fluid between the interior of the sealing bellows 93 and the cryogenic fluid passage 33 is very small, due to the fact that the orifice 89 offers a very small passage section for the cryogenic fluid. The sealing bellows 93 is therefore permanently at a temperature close to that of the heat transfer fluid.

The heat transfer fluid then circulates in the heat transfer fluid circulation side 105 of the heat exchanger 25, from the heat transfer fluid exchanger inlet 109 to the heat transfer fluid exchanger outlet 163. It circulates from from the heat transfer fluid exchanger outlet 163 to the orientation member 159, and is directed to the cooling inlet 149 of the cell cooling circuit 11. The heat transfer fluid is heated by passing through the cell fuel 3, then is directed from the cooling outlet 151 to the inlet of the expansion tank 143.

The assembly described above, in particular the cryogenic valve, has multiple advantages.

Because the heat transfer fluid outlet is annular and surrounds a downstream end portion of the cryogenic fluid passage, it is possible to conveniently connect the cryogenic valve to the heat exchanger, without risk of liquefaction of the air on contact of a surface at very low temperature.

Because the valve body comes from the foundry, in one piece, the valve is extremely economical to produce.

The fact that the surfaces in contact with the cryogenic fluid are machined makes it possible to obtain an excellent surface finish and to guarantee the cleanliness of the hydrogen.

The fact that the internal partitions of the cryogenic valve have a thickness greater than 2 millimeters ensures a high temperature gradient across the internal partitions, and helps ensure that the heat transfer fluid does not freeze in the heat transfer fluid passage.

The fact that the cryogenic valve comprises a sealing bellows arranged around the proximal end portion of the rod carrying the obturator, a proximal end of the bellows being sealed in a sealed manner by welding to the drive member of the The actuator, a distal end of the bellows being sealed in a sealed manner by welding to the at least one internal partition around the guide orifice of the rod, means that the cryogenic valve is particularly sealed in design on the side of the cryogenic fluid. Possible leak points are only at the welds between the bellows and the drive member, and at the welds between the bellows and the internal partition(s).

The flange connection between the exchanger and the cryogenic valve is particularly simple.

The fact of having a heat transfer fluid outlet surrounding the cryogenic fluid outlet on the valve side and a heat transfer fluid inlet surrounding the cryogenic fluid inlet on the heat exchanger side ensures that there is, at no point, a risk of air liquefaction upon contact with surfaces bathed by the cryogenic fluid.

The first and second seals make it possible to isolate the cryogenic gas circuit from the heat transfer fluid circuit in a particularly effective manner. In the event of a leak, these leaks are collected by the channel provided for this purpose and led outside. Optionally, a hydrogen detector is connected to the channel.

The fact that the cryogenic fluid circulation side of the heat exchanger comprises a single tube, made from material, having an upstream end welded to the exchanger flange, means that the number of welds on the cryogenic fluid side of the heat exchanger heat exchanger is minimum. The sources of leaks are drastically limited. Furthermore, this tube is capable of withstanding very high pressures. This type of exchanger, with a single tube, is particularly simple and economical.

As specified above, the fact that the cryogenic valve is placed outside the cryogenic fluid storage unit makes it possible to considerably simplify the design of the cryogenic valve. This is made possible by the fact that the valve body incorporates a passage for a heat transfer fluid which surrounds the cryogenic gas passage.

The assembly and the cryogenic valve described above can have multiple variations.

The actuator, the shutter and the kinematic chain can be of any suitable type, different from the example described above. The actuator is not necessarily a pneumatic actuator but could be electric. The rod could come integrally with the drive member, and not be linked to the drive member by means of a sleeve.

The cryogenic fluid passage may not have a downstream end portion projecting from the valve flange. This passage could stop flush with the bearing surface of the valve flange. Alternatively, the cryogenic fluid exchanger inlet could protrude from the exchanger flange and penetrate inside the cryogenic fluid outlet of the cryogenic valve.

The cryogenic fluid leak evacuation channel could be provided in the flange of the cryogenic valve, and not in the flange of the heat exchanger.

The assembly is not necessarily intended to power a fuel cell. It could power another type of equipment such as an internal combustion engine running on hydrogen as fuel, or in the field of chemistry for the production of products such as ammonia or fertilizer. It is also possible to power boilers to replace gas such as methane.

The cryogenic fluid is not necessarily hydrogen, but could be of any other type: helium, or even oxygen, air, nitrogen, etc.

Claims (10)

Cryogenic valve (23), comprising:
- a valve body (27) delimiting a cryogenic fluid inlet (29), a cryogenic fluid outlet (31) and a cryogenic fluid passage (33) fluidly connecting the cryogenic fluid inlet (29) to the outlet of cryogenic fluid (31);
- a shutter (37);
- an actuator (39);
- a kinematic chain (41) via which the actuator (39) moves the shutter (37) between a position for closing the cryogenic fluid passage (33) and a position for clearing the cryogenic fluid passage (33);
the valve body (27) further delimiting a heat transfer fluid inlet (43), a heat transfer fluid outlet (45) and a heat transfer fluid passage (47) fluidly connecting the heat transfer fluid inlet (43) to the outlet of heat transfer fluid (45), the heat transfer fluid passage (47) extending around the cryogenic fluid passage (33). Valve according to claim 1, in which the heat transfer fluid outlet (45) is annular and surrounds a downstream end portion (51) of the cryogenic fluid passage (33). Valve according to any one of the preceding claims, in which the valve body (27) comes from the casting, in one piece, the valve body (27) having surfaces in contact with the cryogenic fluid, said surfaces being of preferably machined. Valve according to any one of the preceding claims, in which the valve body (27) has at least one internal partition (49) delimiting on one side the passage of cryogenic fluid (33) and on the other side the passage of heat transfer fluid (47), the at least one internal partition (49) having a thickness greater than 2 mm. Valve according to claim 4, wherein the actuator (39) comprises a drive member (75), the kinematic chain (41) comprising a rod (83) having a distal end portion (85) carrying the obturator (37), a proximal end portion (87) linked to the drive member (75) and an intermediate portion engaged in an orifice (89) provided in the at least one internal partition (49), the valve cryogenic (23) comprising a sealing bellows (93) arranged around the distal end portion (87), a proximal end (95) of the sealing bellows (93) being sealingly bonded by welding to the drive member (75), a distal end (97) of the sealing bellows (93) being sealed by welding to the at least one internal partition (49), around the orifice (89). Set (1) including:
- a cryogenic valve (23) according to any one of the preceding claims;
- a heat exchanger (25) having a cryogenic fluid circulation side (103) and a heat transfer fluid circulation side (105), the cryogenic fluid circulation side (103) having a cryogenic fluid exchanger inlet (107), connected to the cryogenic fluid outlet (31) of the cryogenic valve (23), the heat transfer fluid circulation side (105) having a heat transfer fluid exchanger inlet (109), connected to the outlet of heat transfer fluid (45) of the cryogenic valve (23). Assembly according to claim 6, in which the heat exchanger (25) comprises an exchanger flange (111) in which the cryogenic fluid exchanger inlet (107) and the fluid exchanger inlet are provided heat transfer fluid (109), the heat transfer fluid exchanger inlet (109) being annular and surrounding the cryogenic fluid exchanger inlet (107), the cryogenic valve (23) being according to claim 2 and comprising a flange of valve (53) fixed to the exchanger flange (111) in which the cryogenic fluid outlet (31) and the heat transfer fluid outlet (45) are provided. Assembly according to claim 7, in which the valve flange (53) and the exchanger flange (111) are in contact with one another along a contact zone (115) having a portion (117 ) separating the cryogenic fluid exchanger inlet (107) from the heat transfer fluid exchanger inlet (109) and also separating the cryogenic fluid outlet (31) from the heat transfer fluid outlet (45), the one of the valve flange (53) and the exchanger flange (111) comprising a channel (119) fluidly connecting said portion (117) with the outside, the assembly (1) further comprising:
- a first seal (121) interposed between said portion (117) on the one hand and the cryogenic fluid outlet (31) and the cryogenic fluid exchanger inlet (107) on the other hand;
- a second seal (123) interposed between said portion (117) on the one hand and the heat transfer fluid outlet (45) and the heat transfer fluid exchanger inlet (109) on the other hand. Assembly according to any one of claims 7 to 8, in which the cryogenic fluid circulation side (103) comprises a single tube (129), made from material, having an upstream end (131) welded to the exchanger flange (111). Assembly according to any one of claims 7 to 9, in which the assembly comprises a cryogenic fluid storage unit (12) with an internal reservoir (13) internally delimiting a volume (15) for receiving cryogenic fluid, a reservoir external (17) in which the internal reservoir (13) is housed, and a conduit (175) fluidly connecting the cryogenic fluid inlet (29) of the cryogenic valve (23) to the receiving volume (15), the cryogenic valve (23) being arranged outside the external tank (17).