Cryogenic valve

Abstract

Cryogenic Valve The cryogenic valve (1) comprises: - a valve body (27); - a poppet (37); - an actuator (39); - a kinematic chain (41) comprising a driving member (47) moved by the actuator (39) and a transmission structure (49) transmitting the movement of the driving member (47) to the poppet (37); - a tubular bellows (65) arranged around the transmission structure (49), the tubular bellows (65) having internal corrugations (87) projecting into the tubular bellows (65); - Guards (93) made of a low-friction material, placed inside the tubular bellows (65) on the internal corrugations (87), the guards (93) moving with the internal corrugations (87) along the axis of displacement (X) when the driving member (47) is moved along the axis of displacement (X). Figure for the abbreviation: 3

Description

Title of the invention: Cryogenic valve

[0001] The invention relates generally to cryogenic valves.

[0002] More specifically, the invention comprises a cryogenic valve including:

[0003] - a valve body, having a cryogenic fluid inlet, a fluid outlet cryogenic, and a cryogenic fluid passage fluidly connecting the cryogenic fluid inlet to the cryogenic fluid outlet;

[0004] - a valve;

[0005] - an actuator;

[0006] - a kinematic chain through which the valve is moved by the actuator between a position of closing the cryogenic fluid passage and a position of clearing the cryogenic fluid passage, the kinematic chain comprising a driving element moved by the actuator along an axis of displacement and a transmission structure transmitting the movement of the driving element to the valve;

[0007] - a tubular bellows arranged around the transmission structure, having a one end connected to the driving element and a second end connected to the valve body.

[0008] The transmission structure typically comprises a stem engaged through an orifice opening into the cryogenic fluid passage. The orifice is delimited by a guide formed on the valve body, which guides the movement of the stem. The tubular bellows prevents any leakage of cryogenic fluid to the outside of the valve, along the stem.

[0009] The valve is for example intended to be integrated into a cryogenic hydrogen supply assembly for a fuel cell.

[0010] It is for example of the type described in the patent application filed under number FR 22 04567.

[0011] Such a valve is equipped with a double jacket through which a heat transfer fluid circulates, preventing the valve surfaces in contact with hydrogen at very low temperatures from being bathed by the external atmosphere. This could cause the air to liquefy upon contact with said surfaces.

[0012] In this case, the hydrogen circulating in the cryogenic fluid passage can reach a temperature as low as 20 K, with its pressure varying from 3 to 20 bar. The volume inside the tubular bellows is filled with hydrogen in a gaseous state.

[0013] Due to the presence of the double jacket for circulating the heat transfer fluid, the temperature around the valve body, at the coldest point, is around -50°C.

[0014] The tubular bellows, for its part, is at a temperature very close to the temperature of the heat transfer fluid circulating in the double jacket, due to the fact that there is practically no circulation of hydrogen between the passage of circulation of the cryogenic fluid and the volume delimited internally by the tubular bellows.

[0015] The cryogenic valve flap typically has a stroke of 5 mm between its closed position and its open position, so as to allow the flow of cryogenic hydrogen without creating significant back pressure.

[0016] The tubular bellows is typically obtained by hydroforming, from a sheet of 304Ti austenitic stainless steel. In some cases, the tubular bellows may be double-layered, each layer being made of a sheet of austenitic stainless steel.

[0017] The sheet has a very thin thickness, typically between 0.1 and 0.3 mm, to provide the required flexibility, even at low temperatures. Before the hydroforming step, each sheet is rolled and welded to obtain a tube that is subsequently shaped by hydroforming. It is practically impossible to obtain an extruded tube of such a very thin thickness.

[0018] The cryogenic valve must open each time the fuel cell is started and close each time the fuel cell is shut down. Over a vehicle lifespan of fifteen years, the cryogenic valve will undergo approximately twenty-five thousand opening and closing cycles.

[0019] In order for the tubular bellows to be able to withstand the fatigue caused by these repeated openings, the number of corrugations in the tubular bellows can be chosen to be 16, with an outer diameter of 20 mm and an inner diameter of 12 mm, the height being approximately 34.6 mm.

[0020] Due to its manufacturing method using a welded rolled sheet, the tubular bellows' strength is not uniform along its entire height. When the tubular bellows is subjected to internal pressure, there is a risk of buckling at the point where its strength is weakest. One solution to prevent buckling is to increase the diameter of the tubular bellows. However, this has a very significant impact on the size and overall cost of the cryogenic valve, making this solution unsatisfactory.

[0021] It is also impossible to reduce the height of the tubular bellows, which is controlled by the opening stroke of the cryogenic valve flap.

[0022] In the event of buckling, the corrugations protruding inwards from the tubular bellows can rub against all the structures located inside the tubular bellows each time the valve is moved. Due to the thinness of the material constituting the tubular bellows, there is a risk of premature wear of the tubular bellows, and of perforation.

[0023] In this context, the invention aims to provide a cryogenic valve in which the risk of perforation of the tubular bellows is lower.

[0024] To this end, the invention relates to a cryogenic valve, comprising: - a valve body, having a cryogenic fluid inlet, a cryogenic fluid outlet and a cryogenic fluid passage fluidly connecting the cryogenic fluid inlet to the cryogenic fluid outlet;

[0025] - a valve;

[0026] - an actuator;

[0027] - a kinematic chain through which the valve is moved by the actuator between a position of closing the cryogenic fluid passage and a position of clearing the cryogenic fluid passage, the kinematic chain comprising a driving element moved by the actuator along an axis of displacement and a transmission structure transmitting the movement of the driving element to the valve;

[0028] - a tubular bellows arranged around the transmission structure, having a first end connected to the driving element and a second end connected to the valve body, the tubular bellows having internal corrugations projecting towards the inside of the tubular bellows, the tubular bellows being compressible along the axis of displacement under the effect of the displacement of the driving element;

[0029] - protective elements made of a material with a low coefficient of friction, placed inside the tubular bellows on the internal corrugations, the guards moving with the internal corrugations along the axis of movement when the driving organ is moved along the axis of movement.

[0030] Thus, the guards protect against internal corrugations during the movements of the cryogenic valve flap.

[0031] Indeed, with each movement of the valve, the driving element moves along the axis of movement, carrying the tubular bellows with it. The internal corrugations of the tubular bellows closest to the driving element will have a stroke substantially equal to that of the cryogenic valve's valve.

[0032] The internal corrugations closest to the end connected to the valve body will move over a short stroke. The intermediate internal corrugations will have a stroke approximately half that of the cryogenic valve flap.

[0033] The protections will move with the internal corrugations, and it is they that will come into contact with the structures housed inside the tubular bellows in the event of buckling of the tubular bellows.

[0034] Because these protections are made of a material with a low coefficient of friction, these contacts will not prevent the opening and closing of the cryogenic valve flap.

[0035] The cryogenic valve may further have one or more of the following characteristics, considered individually or in all technically possible combinations:

[0036] - the protectors are rings, each ring being mounted on one of the cor- internal rugas;

[0037] - the rings are closed contour, or are open;

[0038] - each protector has an external groove in which the cor- internal rugation;

[0039] - the protections are independent of each other, or are linked to each other others by compressible junctions along the direction of displacement;

[0040] - the valve comprises a corrugated tube placed inside the tubular bellows, the tube corrugated including hollow undulations towards the tubular bellows, defining the protections;

[0041] - the transmission structure comprises a rod extending along the axis of development placement, the valve body comprising a guide guiding the stem in translation along the axis of movement, the tubular bellows being placed around the guide with interposition of a sleeve made of a material with a low coefficient of friction between the guide and the guards;

[0042] - the transmission structure comprises a shaft integral with the driving member to which is fixed a proximal end of the rod, the tubular bellows being placed around the barrel with interposition of another sleeve made of a material with a low coefficient of friction between the barrel and the guards;

[0043] - the protections are distributed into two to four groups, the protections of the same groups being linked to one another, protections belonging to different groups being free from one another;

[0044] - the tubular bellows comprises at least one corrugated tube, obtained from a welded rolled sheet, preferably less than 0.5 mm thick.

[0045] Other features and advantages of the invention will become apparent from the detailed description given below, by way of example and not limitation, with reference to the accompanying figures, among which: - [Fig.1] The [Fig.1] is a simplified schematic representation of an assembly comprising a fuel cell, a hydrogen storage and a supply circuit incorporating a cryogenic valve according to the invention; - [Fig. 2] [Fig. 2] is a cross-sectional representation of the cryogenic valve of [Fig.1], the guards are not shown for clarity; - [Fig.3] The [Fig.3] is a schematic representation in section and in perspective of part of the valve of [Fig.2], the protections being shown; - [Fig. 4] Fig. 4 is a perspective view of one of the protective devices equipping the valve of the [Fig.3]; - [Fig. 5] [Fig. 5] is a view similar to that of [Fig. 4], for a variant implementation of protection; - [Fig. 6][Fig. 7] Figures 6 and 7 are enlarged views of a detail of the [Fig.3], showing the positions of the guards when the valve is in the closed position and when the valve is in the open position respectively; - [Fig.8] Fig.8 is a perspective view of the protections for a second method of implementing the invention; - [Fig.9][Fig.10] Figures 9 and 10 are views similar to those of figures 6 and 7, for the protections of [Fig.8]; - [Fig.l 1] The [Fig.l 1] is a perspective view of the guards for a third embodiment of the invention; - [Fig. 12] [Fig. 13] Figures 12 and 13 are views similar to those in Figures 6 and 7, for the guards of [Fig. 11]; and - [Fig. 14] The [Fig. 14] is a view similar to that of the [Fig.3], for an alternative embodiment applicable to all embodiments.

[0046] Valve 1 is a cryogenic valve, that is to say a valve intended to be inserted in a circuit in which a cryogenic fluid circulates.

[0047] A cryogenic fluid is understood to be a fluid at a very low temperature, which is stored at least partially in a liquid state.

[0048] In the example of [Fig.1], the cryogenic fluid is hydrogen.

[0049] In other applications, the cryogenic fluid is helium, nitrogen, a natural gas such as methane CH4, air, or any other suitable fluid.

[0050] In the example shown in [Fig.1], the cryogenic valve 1 is integrated into an assembly 3 comprising a fuel cell 5 and a cryogenic fluid storage tank 7.

[0051] The cryogenic valve 1 is intercalated in a circuit 9 supplying the fuel cell 5 with cryogenic fluid from the cryogenic fluid storage tank 7.

[0052] The fuel cell 5 supply circuit 9 includes, downstream of the cryogenic valve 1, a heater 11 which is typically a heat exchanger.

[0053] Assembly 3 is typically intended to be mounted 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.

[0054] The fuel cell 5 is configured to produce electricity and power the electric propulsion motor.

[0055] In a conventional manner, the fuel cell 5 comprises an anodic gas circuit, a cooling circuit, and a cathodic gas circuit, these different circuits not being shown.

[0056] Cathode gas is a gas containing oxygen, for example air.

[0057] The anodic gas is typically hydrogen. The supply circuit 9 is thus connected to the inlet of the anodic gas circuit.

[0058] As can be seen in [Fig.2], the cryogenic valve 1 comprises:

[0059] - a valve body 27 delimiting a cryogenic fluid inlet 29, an outlet of cryogenic fluid 31 and a cryogenic fluid passage 33 fluidically connecting the cryogenic fluid inlet 29 to the cryogenic fluid outlet 31;

[0060] - a valve 37;

[0061] - an actuator 39;

[0062] - a kinematic chain 41 through which the valve 37 is moved by the actuator 39 between a position of closing the cryogenic fluid passage 33 and a position of clearing the cryogenic fluid passage 33.

[0063] The cryogenic fluid inlet 29 is fluidly connected to an outlet port of the cryogenic fluid storage tank 7.

[0064] Advantageously, the valve body 27 further delimits a heat transfer fluid inlet 43, a heat transfer fluid outlet not shown and a heat transfer fluid passage 45 fluidly connecting the heat transfer fluid inlet 43 to the heat transfer fluid outlet.

[0065] Preferably, the heat transfer fluid passage 45 is arranged around the cryogenic fluid passage 33, so that the surfaces of the valve body 27 in contact with the cryogenic fluid are not directly exposed to the atmosphere surrounding the cryogenic valve 1.

[0066] For example, the heat exchanger 11 has a cryogenic fluid circulation side and a heat transfer fluid circulation side, the cryogenic fluid and the heat transfer fluid being in thermal contact with each other within the heat exchanger 11.

[0067] The cryogenic fluid circulation side has an inlet connected to the cryogenic fluid outlet 31 of the cryogenic valve 1. It also has an outlet, connected to the inlet of the anodic fluid circuit of the fuel cell 5.

[0068] The heat transfer fluid circulation side is for example connected to the cooling circuit of the fuel cell 5.

[0069] The heat transfer fluid inlet 43 and the heat transfer fluid outlet of the cryogenic valve 1 are typically fluidically connected in bypass on the heat transfer fluid circulation side of the heat exchanger 11.

[0070] The kinematic chain 41 includes a driving element 47 moved by the actuator 39 along an axis of displacement X, and a transmission structure 49 transmitting the movement of the driving organ 47 to the valve 37 of the cryogenic valve 1.

[0071] In the example shown, the actuator 39 is of the pneumatic type. It comprises an actuator body 51 delimiting an internal space divided into two volumes by a diaphragm 53. The diaphragm 53 moves a lug 55 projecting along the axis of movement X out of the actuator body 51.

[0072] The driving organ 47 is a plate integral with the lug 55.

[0073] The driving member 47 extends perpendicularly to the axis of displacement X. In the example shown, it is circular.

[0074] The transmission structure 49 includes a rod 57.

[0075] The rod 57 extends along the axis of displacement X.

[0076] The stem 57 has a distal end 59 fixed to the valve 37.

[0077] The transmission structure 49 further comprises a shaft 61 integral with the organ leader 47.

[0078] A proximal end 63 of the rod 57 is fixed to the shaft 61.

[0079] In the example shown, the shaft 61 delimits a blind housing in which the proximal end 63 of the rod 57 is fixed.

[0080] As seen in [Fig.2], a tubular bellows 65 is arranged around the transmission structure 49. The tubular bellows 65 has a first end 67 connected to the driving member 47 and a second end 69 connected to the valve body 27.

[0081] The tubular bellows 65 is coaxial with the axis of displacement X. It is compressible along the axis of displacement X under the effect of the displacement of the driving member 47.

[0082] More specifically, the valve body 27 has an internal partition 71 separating the heat transfer fluid passage 45 from the cryogenic fluid passage 33. This internal partition 71 has an orifice 73 through which the stem 57 passes. The orifice 73 is formed in a portion 75 of the internal partition 71 substantially perpendicular to the axis of movement X.

[0083] The tubular bellows 65 is in a watertight bearing by its second end 69 on said portion of partition 75, and surrounds the orifice 73. The first end 67 of the tubular bellows 65 is in a watertight bearing on an internal face 76 of the driving member 47 which is opposite the portion of partition 75. It surrounds the barrel 61.

[0084] The cryogenic valve 1 further includes a return element 77 that returns the valve 37 to its closed position. In the example shown, the return element 77 is a helical spring coaxial with the axis of movement X. One end of the spring bears against the partition portion 75. The opposite end bears against the inner face 76 of the actuating element 47.

[0085] The helical spring 77 surrounds the tubular bellows 65 and is placed outside of it.

[0086] It should be noted that the cryogenic valve 1 has a hood 79 mounted on the valve body 27. The internal volume of the hood 79 communicates with the heat transfer fluid circulation passage 45 via an opening 81 provided in the valve body 27.

[0087] The opening 81 is opposite the portion of partition 75 along the axis of movement X. The return member 77, the tubular bellows 65 and the rod 57 pass through the opening 81 and are housed inside the hood 79.

[0088] The valve body 27 includes a guide 83 guiding the stem 57 in translation along the axis of displacement X.

[0089] The guide 83 is a tubular portion of the valve body 27, extending along the axis of movement X from the portion of partition 75. It delimits a passage 85 extending the orifice 73 towards the driving member 47. The internal section of this passage 85 is substantially identical to the external section of the stem 57.

[0090] The tubular bellows 65 is placed around the guide 83.

[0091] It is also placed around the barrel 61.

[0092] Thus, the internal volume of the tubular bellows 65 is filled by hydrogen gas, which infiltrates between the guide 83 and the rod 57 from the passage of cryogenic fluid 33.

[0093] On the other hand, the volume located outside the tubular bellows 65 is filled by the heat transfer fluid.

[0094] As can be seen more clearly in figures 3 to 6, the tubular bellows 65 has internal corrugations 87 projecting towards the inside of the tubular bellows 65. It also has external corrugations 89, projecting towards the outside of the tubular bellows 65.

[0095] Each internal corrugation 87 is connected to two external corrugations 89, and conversely each external corrugation 89 is connected to two internal corrugations 87.

[0096] The internal corrugations 87 each extend along a closed contour around the axis of displacement X.

[0097] Considered in section in a plane containing the axis of displacement X, they present substantially a section in the form of a semicircle open on the opposite side of the axis of displacement X.

[0098] Similarly, the external corrugations 89 each extend along a closed contour all around the axis of displacement X.

[0099] Considered in section in a plane containing the axis of displacement X, as in figures 6 and 7, the external corrugations 89 have a semi-circular shape open towards the axis of displacement X.

[0100] The internal corrugations 87 are distributed along the displacement axis X and spaced axially apart. Similarly, the external corrugations 89 are distributed along the displacement axis X, and are placed axially between the internal corrugations 87.

[0101] The internal corrugations 87 and the external corrugations 89 are connected to each other by substantially annular portions 91 of the tubular bellows 65, extending in planes perpendicular to the axis of displacement X.

[0102] According to the invention, protectors 93 made of a material with a low coefficient of friction are placed inside the tubular bellows 65 on the internal corrugations 87.

[0103] The guards 93 move with the internal corrugations 87 along the axis of displacement X when the driving member 47 is moved along the axis of displacement X.

[0104] According to a first embodiment, shown in figures 3 to 7, the protectors 93 are rings, each ring being mounted on one of the internal corrugations 87.

[0105] As illustrated in [Fig.4], the rings have a closed contour.

[0106] Each protection 93 has an external groove 95, in which the internal corrugation 87 is engaged.

[0107] More specifically, the protection 93 is circular, centered on the axis of displacement X.

[0108] Considered in section in a plane containing the axis of displacement X, it has a substantially rectangular shape, as can be seen more clearly in figures 6 and 7.

[0109] Thus, it is delimited radially inwards by an internal surface 97 substantially cylindrical.

[0110] The external groove 95 is cut into a radially external surface 98 of the protection 93.

[0111] Considered in section in a plane containing the axis of displacement X, the external groove 95 has an internal section of the same shape as the external section of the internal corrugation 87.

[0112] The radially internal surfaces 97 and radially external surfaces 98 of the guards 93 are connected to each other by substantially flat slices 99, inscribed in planes perpendicular to the axis of displacement X.

[0113] The 93 protections are independent of each other. This means that the 93 protections did not originate from one another as a unit of matter, and are not directly connected to each other by material bridges. They are free in relation to each other.

[0114] The 93 protectors are made of a material that is particularly resistant to friction, compatible with cryogenic fluid, and has sufficient rigidity.

[0115] For example, the 93 protectors are made of polytetrafluoroethylene (PTFE) or Teflon.

[0116] Preferably, a sleeve 101 made of a material with a low coefficient of friction is interposed between the guide 83 and the guards 93.

[0117] The sleeve 101 is cylindrical, coaxial with the axis of displacement X. It is placed on the external surface of the guide 83. In other words, it is threaded around the guide 83 and is pressed against its external surface.

[0118] For example, the sleeve is made of PTFE or of a metal with particularly low roughness.

[0119] Similarly, another sleeve 103 is interposed between the barrel 61 and the protectors 93.

[0120] The other sleeve 103 is cylindrical, coaxial with the axis of displacement X. It is placed against the external surface of the barrel 61. In other words, it is threaded around the barrel 61 and pressed against its external surface.

[0121] It is advantageously made of the same material as sleeve 101.

[0122] It should be noted that the barrel 61 is spaced from the guide 83, with a distance at least equal to the stroke of the valve 37 when it moves from its closed position to its open position.

[0123] The protectors 93 are threaded around the sleeve 101, and around the other sleeve 103. Their internal surfaces 97 have a diameter substantially equal to or slightly greater than the external diameter of the sleeve 101 and the external diameter of the other sleeve 103.

[0124] When the tubular bellows 65 undergoes compression related to the axial displacement of the driving member 47, the internal surface 97 of the guards 93 slides against the external surface of the sleeve 101 or the other sleeve 103.

[0125] This situation is illustrated in figures 6 and 7.

[0126] Figure 6 illustrates the positions of the guards 93 when the valve 37 is in its closed position. The guards 93 are axially separated from each other and separated by gaps 105.

[0127] When the valve 37 is moved by the actuator from its closed position to its open position, the driving member 47 moves axially along the axis of movement X. It pushes the rod 57 and compresses the tubular bellows 65. As a result, the internal corrugations 87 move closer together.

[0128] It should be noted that the internal corrugations 87 closest to the driving member 47, that is, those located at the first end 67 of the tubular bellows 65, will move over a stroke corresponding substantially to that of the driving member 47, itself substantially equal to the stroke of the valve 37. The internal corrugations 87 located at the second end 69 of the tubular bellows 65, fixed to the valve body 27, will hardly move at all. The intermediate internal corrugations 87 will move over a shorter stroke than the internal corrugations located at the first end 67 of the tubular bellows 65.

[0129] Thus, the races of the different protections 93 are different from each other, and increase as we approach the leading organ 47.

[0130] The situation when the flap 37 has reached its open position is illustrated in [Fig. 7]. The guards 93 are located immediately next to each other and typically touch. Their edges 99 are in contact with each other.

[0131] According to a variant of the first embodiment illustrated in [Fig.5], the protectors 93 are open rings.

[0132] These rings are substantially the same shape as those previously described, except that they have a 106 interruption of small angular width, as illustrated in [Fig.5].

[0133] The variant of [Fig.5] facilitates the placement of the protectors 93 on the internal corrugations 87. The external groove 95, in this case, can be deeper than for closed rings.

[0134] A second embodiment of the invention will now be described, with reference to Figures 8 to 10. Only the points by which this second embodiment differs from the first will be detailed below.

[0135] Identical elements or elements performing the same functions in both embodiments shall be designated by the same references.

[0136] In the embodiment of figures 3 to 7, the protections 93 are independent of each other.

[0137] In the second embodiment, the protections 93 are linked to each other by compressible junctions 107 along the axis of displacement X.

[0138] The protections 93 have substantially the same shape as in the first embodiment.

[0139] The compressible junctions 107 are made of the same material as the protectors 93.

[0140] Compressible junctions 107 are material bridges connecting the protective elements 93 to each other. They came from the material with the 93 protections.

[0141] The compressible junctions 107 are preferably membranes.

[0142] As can be seen in Figures 4 and 5, the groove 95 of each guard is delimited by two edges 108. Each edge 108 is situated along and opposite one of the edges 108 of the adjacent guard 93. As shown in Figures 8 to 10, the compressible joint 107 connects said edge 108 to the opposite edge 108 belonging to the adjacent guard 93.

[0143] Thus, each protection 93 is connected by its two edges 108 to the protections 93 located axially on either side via the compressible junctions 107.

[0144] Considered in section in a plane containing the axis of displacement X, the compressible junctions 107 have a substantially V-shaped form, pointing radially opposite to the axis of displacement X.

[0145] As can be seen in figures 9 and 10, the compressible junctions 107 are each engaged in the space delimited between two internal corrugations 87. This facilitates the movement of the guards 93 along the axis of displacement X during compression or extension of the tubular bellows 65.

[0146] Fig. 9 represents the situation when the valve 37 is in its closed position.

[0147] The guards 93 are spaced from each other along the axis of displacement X and separated by gaps 105. The compressible junctions 107 each have relatively open V-shaped sections.

[0148] Figure 10 represents the situation when the valve 37 is in its open position. The internal corrugations 87 have moved closer together axially. As a result, the guards 93 have also moved closer together axially, under the effect of the compression of the tubular bellows 65. However, they are not in contact with each other via their edges 99. A small gap remains between the guards 93. The compressible junctions 107 have, in cross-section, a less open V-shape than in the situation of Figure 9.

[0149] As in the first embodiment, the protective elements 93 are advantageously open rings and have interruptions 106. The compressible junctions 107 also have interruptions 109. The interruptions 106 and 109 are axially aligned. Together, the protective elements 93 and the compressible junctions 107 form a slotted tube. This tube has a slot 110 extending axially along its entire length.

[0150] The presence of the slot 110 facilitates the placement of the protectors 93 on the internal corrugations 87.

[0151] According to an unshown variant, the protective elements 93 are closed rings. The compressible junctions 107 have a closed contour. Together, the protective elements 93 and the compressible junctions 107 form a closed tube.

[0152] To facilitate the placement of the protections 93 on the internal corrugations 87, the external grooves 95 are less deep than in the embodiment variant where the protections 93 and the compressible junctions 107 form an open tube.

[0153] A third embodiment of the invention will now be detailed, with reference to Figures 11 to 13.

[0154] Only the points by which the third embodiment differs from the first embodiment will be detailed below. Identical elements or elements performing the same function will be designated by the same reference numerals.

[0155] In the third embodiment, the cryogenic valve 1 comprises a corrugated tube 111 placed inside the tubular bellows 65.

[0156] The corrugated tube 111 is substantially coaxial with the axis of displacement X. The tube ringed 111 includes undulations 113 in hollow towards the tubular bellows 65.

[0157] It also includes undulations 115 projecting towards the tubular bellows 65.

[0158] Each hollow undulation 113 is annular and extends around the axis of displacement X. Similarly, each protruding undulation 115 is annular and extends around the axis of displacement X. The hollow undulations 113 are axially spaced from each other, the protruding undulations 115 being placed each between two hollow undulations 113.

[0159] In other words, the protruding undulations 115 connect the recessed undulations 113 in pairs, and the recessed undulations 113 connect the protruding undulations 115 in pairs.

[0160] Considered in section in a plane containing the axis of displacement X, the corrugated tube 111 has a wavy shape.

[0161] The hollow undulations 113, considered in section in a plane containing the axis of displacement X, have the shape of a circular arc. Similarly, the protruding undulations 115, considered in section in a plane containing the axis of displacement X, have the shape of a circular arc.

[0162] The hollow undulations 113 define the protections 93.

[0163] In other words, each internal corrugation 87 is housed in a hollow undulation 113.

[0164] The projecting undulations 115 are each engaged between two internal corrugations 87 that are close to each other.

[0165] As can be seen in figures 12 and 13, the apex of the hollow undulations 113 is placed on the sleeve 101 or on the other sleeve 103, except for the hollow undulations 113 located in the gap between the two sleeves 101, 103.

[0166] Figure 12 represents the situation when the valve 37 is in its closed position. The axial spacing between the hollow undulations 113 corresponds approximately to the axial spacing between the internal corrugations 87. In cross-section, the corrugated tube 111 has a sinusoidal shape.

[0167] Figure 13 illustrates the situation when the valve 37 is in its clearance position. The hollow undulations 113 are axially closer together than in Figure 12, as are the internal corrugations 87. Considered in section, the corrugated tube 111 has a sinusoidal shape, with a shorter period than in Figure 12.

[0168] The corrugated tube 111, in the example of [Fig.1 1], is split along its entire height.

[0169] Alternatively, it is closed.

[0170] According to an alternative embodiment shown in [Fig.14], the protections 93 are distributed into two to four groups, the protections 93 of the same group being linked to each other.

[0171] The protections 93 belonging to different groups are free from each other relationship with others.

[0172] In the example of [Fig. 14], the protections 93 are distributed in three groups.

[0173] The 93 protections of the same group are linked to each other by bridges of matter. They typically came from matter, from one another.

[0174] On the contrary, there is no direct mechanical link, for example by material bridges, between the different protection groups 93. Each protection group 93 forms a cylindrical body, coaxial with the axis of displacement X, independent of the other bodies.

[0175] In this embodiment, there is a gap between the protection groups 93. The internal corrugations 87, located at the right of this gap, are not equipped with protection 93.

[0176] As indicated in the preamble to this description, the tubular bellows 65 comprises at least one corrugated tube obtained from a welded rolled sheet.

[0177] For example, the tubular bellows 65 consists of a single corrugated tube. Alternatively, the tubular bellows 65 comprises two corrugated tubes nested one inside the other and of the same shape.

[0178] Each corrugated tube preferably has a thickness between 0.1 and 0.5 mm, more precisely between 0.1 and 0.4 mm and advantageously substantially equal to 0.3 mm.

[0179] Each corrugated tube is made of 304 Ti austenitic stainless steel.

[0180] For example, the tubular bellows 65 has sixteen internal corrugations 87 and sixteen External corrugations 89. The external diameter of the tubular bellows 65, measured at the external corrugations 89, is approximately 20 mm. The internal diameter, measured at the internal corrugations 87, is approximately 12 mm. The tubular bellows 65 has an axial height of 34.6 mm.

[0181] The stroke of the valve 37, between its closed position and its open position, is axially approximately 5 mm.

[0182] The valve described above has multiple advantages.

[0183] Ring-shaped protectors are particularly well suited to protect internal corrugations.

[0184] When the rings are open, it is particularly easy to mount them on internal corrugations.

[0185] When each guard has an external groove in which the internal corrugation is engaged, the mounting of the guard on the internal corrugation is facilitated, and the guard naturally follows the axial displacement of the internal corrugation.

[0186] When the guards are independent of each other, they easily follow the movement of the internal corrugations, and the resistance to opening or closing the valve is reduced.

[0187] When the guards are linked to each other by compressible junctions, the number of parts to be managed is reduced.

[0188] When the valve includes a corrugated tube placed inside the tubular bellows, whose hollow undulations towards the tubular bellows define the protections, the production cost is reduced.

[0189] The sleeve made of low coefficient of friction material inserted between the rod guide and the guards helps to reduce wear on the guards.

[0190] Similarly, the other sleeve made of a material with a low coefficient of friction, arranged between the barrel carried by the driving element and the guards, also helps to reduce wear on the guards.

[0191] When the tubular bellows comprises at least one corrugated tube, obtained from a welded rolled sheet, the buckling of the tubular bellows, which may result from an area of ​​lower resistance within the tubular bellows, does not lead to premature wear of the tubular bellows. The buckling simply results in a more pronounced bearing of the protective elements against the components located inside the tubular bellows.

[0192] The cryogenic valve can have multiple variants.

[0193] It may not include a passage for a heat transfer fluid.

[0194] The actuator and the kinematic chain can be of any suitable type. The actuator can be an electric actuator, or any other suitable type of actuator. The driving element is not necessarily a plate and can be a rod, a diaphragm, etc. The transmission structure may include linkages.

Claims

Claims

1. Cryogenic valve (1), comprising: - a valve body (27), having 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 valve (37); - an actuator (39); - a kinematic chain (41) by means of which the valve (37) is moved by the actuator (39) between a position for closing the cryogenic fluid passage (33) and a position for clearing the cryogenic fluid passage (33), the kinematic chain (41) comprising a driving member (47) moved by the actuator (39) along a movement axis (X) and a transmission structure (49) transmitting the movement of the driving member (47) to the valve (37);- a tubular bellows (65) arranged around the transmission structure (49), having a first end (67) connected to the driving member (47) and a second end (69) connected to the valve body (27), the tubular bellows (65) having internal corrugations (87) projecting towards the inside of the tubular bellows (65), the tubular bellows (65) being compressible along the axis of movement (X) under the effect of the movement of the driving member (47); - protections (93) made of a material with a low coefficient of friction, placed inside the tubular bellows (65) on the internal corrugations (87), the protections (93) moving with the internal corrugations (87) along the axis of movement (X) when the driving member (47) is moved along the axis of movement (X);the protections (93) are distributed in two to four groups, the protections (93) of the same group being linked to each other, the protections (93) belonging to different groups being free with respect to each other.;

2. A cryogenic valve (1) according to claim 1, wherein the shields (93) are rings, each ring being mounted on one of the internal corrugations (87).

3. Cryogenic valve (1) according to claim 2, in which the rings (93) are closed contour, or are open.

4. A cryogenic valve (1) according to claim 2 or 3, wherein each protection (93) has an external groove (95) in which the internal corrugation (87) is engaged.

5. Cryogenic valve (1) according to any one of claims 2 to 4, in which the protections (93) are independent of each other, or are linked to each other by junctions (107) compressible according to the direction of movement (X).

6. A cryogenic valve (1) according to claim 1, wherein the valve (1) comprises a corrugated tube (111) placed inside the tubular bellows (65), the corrugated tube (111) comprising corrugations (113) extending hollow towards the tubular bellows (65), defining the protections (93).

7. Cryogenic valve (1) according to any one of the preceding claims, in which the transmission structure (49) comprises a rod (57) extending along the axis of movement (X), the valve body (27) comprising a guide (83) guiding the rod (57) in translation along the axis of movement (X), the tubular bellows (65) being placed around the guide (83) with the interposition of a sleeve (101) made of a material with a low coefficient of friction between the guide (83) and the protections (93).

8. Cryogenic valve (1) according to claim 7, in which the transmission structure (49) comprises a barrel (61) integral with the driving member (47) to which a proximal end (63) of the rod (57) is fixed, the tubular bellows (65) being placed around the barrel (61) with the interposition of another sleeve (103) made of a material with a low coefficient of friction between the barrel (61) and the protections (93).

9. Cryogenic valve (1) according to any one of the preceding claims, wherein the tubular bellows (65) comprises at least one corrugated tube, obtained from a welded rolled sheet, preferably with a thickness of less than 0.5 mm.

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