Safety valve for pressure vessel

Abstract

Safety valve (1) for a pressure device comprising: - a valve housing (3) arranged to connect the safety valve (1) to the pressure device, - a transfer channel (8) arranged to be in fluidic communication with the pressure device, - a drain channel (7), - a sealing element (6) arranged to seal the transfer channel (8) when it is in a sealed state and arranged to allow free passage between the transfer channel (8) and the drain channel (7) when it is in a drained state, - an electro-pyrotechnic device (2), - a thermal release element (4) arranged to maintain the sealing element (6) in the sealed state below a predetermined activation temperature and to allow free passage of the sealing element (6) above the activation temperature,characterized in that the thermal release element (4) is arranged between the sealing element (6) and the electro-pyrotechnic device (2) such that the electro-pyrotechnic device (2) participates in maintaining the sealing element (6) in the sealed state. Figure for the abstract: Fig. 1,

Description

Title of the invention: Safety valve for a pressure device Technical field of the invention

[0001] The present invention relates generally to a safety device for pressure vessels such as tanks or distribution networks. Such vessels may be static or mobile and may store or distribute gases or liquids. They may be mounted, for example, on vehicles to store and / or distribute hydrogen. State of the art

[0002] Safety valves, which are mostly passive, are known in the prior art. Document DE8702136 discloses such a device, which also has the option of being activated on command. However, this system is bulky and requires numerous parts. The invention therefore aims to reduce the size of the device to make it easier to integrate and to reduce its number of components. Description of the invention

[0003] One object of the present invention is to address the disadvantages of the prior art mentioned above and in particular, first of all, to provide a more compact safety valve.

[0004] To this end, a first aspect of the invention relates to a safety valve for a pressure device comprising: - a valve housing arranged to connect the safety valve to the pressurized device, - a transfer channel arranged to be in fluidic communication with the pressurized device, - a drainage channel, - a sealing element arranged to seal the transfer channel when it is in a sealed state and arranged to leave a passage free between the transfer channel and the discharge channel when it is in a discharged state, - an electro-pyrotechnic device, - a thermal release element arranged to maintain the sealing element in the sealed state below a predetermined activation temperature and to allow the sealing element to open above the activation temperature, characterized in that the thermal release element is arranged between the sealing element and the electro-pyrotechnic device so that the electro-pyrotechnic device participates in maintaining the sealing element in the sealed state. In other words, the safety valve is designed so that the pressure within the pressure vessel is sufficient, when the thermal release element has released (or no longer holds) the sealing element, to open the passage between the transfer channel and the discharge channel, a passage initially sealed or closed by the sealing element. For example, the safety valve is suitable for protecting a hydrogen storage tank at a nominal pressure of approximately 700 bar. However, it may not be designed to protect across the entire pressure range, depending on the tank's construction; the valve may be configured only to drain the tank when the pressure exceeds a predetermined value, such as 150, 180, or 200 bar.Typically, according to this implementation, the electro-pyrotechnic device participates in the positioning (or holding) of the thermal release element and thus integrates at least two functions with respect to thermal release, namely positioning in its rest position and breaking in its activated position. Therefore, fewer parts and less clearance are required to integrate these two functions, making the safety valve more compact.

[0005] The invention can then be defined with the following characteristics, taken individually or in combination.

[0006] According to one embodiment, the sealing element may be a slide or a frangible element. In other words, the sealing element may be a movable element such as a slide, a needle, a valve, or a frangible element arranged to deform, break, or split. In other words, when no longer supported, the sealing element can be displaced or plastically deformed to open the passage between the transfer channel and the discharge channel.

[0007] According to one embodiment, the thermal release element may be a thermal bulb arranged to rupture above a predetermined activation temperature. In other words, the thermal release element is a thermal triggering element commonly referred to as a thermo bulb. Such an element may consist of a container or bulb containing a liquid, the element being arranged to rupture due to the expansion of said liquid or an increase in pressure inside the container beyond a predetermined temperature. When the thermal release element ruptures, the support of the sealing element is no longer ensured, and the pressurized device can be emptied.

[0008] According to one embodiment, the valve housing may include at least one exchange port separate from the drain channel and the transfer channel and arranged to establish fluidic communication between the heat release element and the external environment of the safety valve. The exchange port ensures that the ambient temperature of the safety valve will be rapidly applied or perceived by the heat release element.

[0009] According to one embodiment, the electro-pyrotechnic device may comprise, or may be, an electro-pyrotechnic igniter arranged in direct contact with the thermal release element. According to this embodiment, the number of parts is further reduced and the responsiveness of the valve is improved.

[0010] According to one embodiment, the safety valve may comprise: - a piston arranged to move between a rest position and an activated position, - The electro-pyrotechnic device is an electro-pyrotechnic igniter arranged to move the piston from the rest position to the activated position upon an electrical ignition pulse. In this embodiment, the piston is a movable transfer element arranged between the electro-pyrotechnic igniter and the thermal release element so as to transfer a force and / or pressure generated by the electro-pyrotechnic igniter to the thermal release element.

[0011] According to one embodiment, the piston can be in direct contact with the thermal release element. According to this embodiment, the responsiveness of the valve is improved.

[0012] According to one embodiment, the electro-pyrotechnic device, the thermal release element, and the sealing element can be arranged coaxially along a spindle axis for the electrical connection of the electro-pyrotechnic device. According to this embodiment, the overall size of the valve is reduced.

[0013] According to one embodiment, the thermal release element and the sealing element can be arranged coaxially along a drainage axis distinct from an electrical connection spindle axis of the electro-pyrotechnic device.

[0014] According to one embodiment, the electro-pyrotechnic device may include an actuation housing arranged to interface with the valve housing. According to this embodiment, the valve manufacturing process is more flexible. Indeed, the same valve housing can be used for an active valve according to the invention or for a purely passive valve.

[0015] According to one embodiment, the actuation housing can interface with the valve housing via a screw interface or a tight fit.

[0016] According to one embodiment, the actuation housing and the electropyrotechnic device can form an actuation subassembly. According to this embodiment, the valve manufacturing process is more flexible.

[0017] According to one embodiment, the safety valve may include a deformable shim arranged to help retain the thermal release element. According to this embodiment, the retention or shimming of the thermal release element is optimized and assembly is facilitated. Indeed, the deformable shim makes it possible to compensate for assembly clearances of the safety valve and / or The manufacturing tolerances of the various components and / or the displacement or deformation of components during the service life of the safety valve. The deformable shim can be in the form of an O-ring or flat seal, a conical washer, or any other shape compatible with the function. The deformable shim can be made of metal and / or natural or synthetic rubber and / or EPDM. The shim can be integral with the piston, mounted on the piston, or be the piston itself. The shim can be a spring. Description of the figures

[0018] Other features and advantages of the present invention will become more apparent upon reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0019] [Fig-1] represents a cross-sectional view of a safety valve according to a first embodiment of the invention, the cut of [Fig.1] being made according to a cutting plane comprising an axis of electrical connection spindle of the electropyrotechnic device;

[0020] [Fig.2] represents the safety valve of [Fig.1] with the piston in its position activated and the shutter element released;

[0021] [Fig.3] represents a cross-sectional view of a safety valve according to a second embodiment of the invention, the cross-section of [Fig.2] being made along a cutting plane comprising an electrical connection spindle axis of the electropyrotechnic device;

[0022] Detailed description of embodiment(s)

[0023] Figure 1 represents a safety valve 1 for a pressure device comprising: - a valve housing 3 arranged to connect the safety valve 1 to the pressurized device, - a transfer channel 8 arranged to be in fluidic communication with the pressurized device, - a drainage channel 7, - a sealing slide 6 arranged to seal the transfer channel 8 when it is in a sealed state as shown in [Fig.1] and arranged to leave a passage free between the transfer channel 8 and the drain channel 7 when it is in a drained state as shown in [Fig.2], - an electro-pyrotechnic device 2 consisting of an electro-pyrotechnic igniter 21 and a piston 23 arranged movably between a rest position and an activated position for the ignition of the electro-pyrotechnic igniter 21, - a thermal release element 4 formed of a frangible bulb 42 enclosing a liquid 41 arranged to maintain the shutter slide 6 in the shuttered state below a predetermined activation temperature and to leave the shutter slide 6 free above the activation temperature.

[0024] The sealing slide 6 is arranged to move in translation along the axis of the transfer channel 8. The seal between the sealing slide 6 and the transfer channel 8 is ensured by a sealing O-ring 61. The sealing slide 6 is further wedged along its axis of translation by a flexible wedge element 62 which can take the form of an O-ring with a suitable hardness.

[0025] The thermal release element 4 is arranged between the sealing slide 6 and the piston 23 of the electro-pyrotechnic device 2 such that the electro-pyrotechnic device 2 participates in maintaining or locking the sealing slide 6 in the closed state. Thus, when pressure is applied to the sealing slide 6, typically by the pressure present in the pressurized device, the sealing slide 6 cannot move since it is held in place by the thermal release element 4 and the electro-pyrotechnic device 2, and in particular by the piston 23.

[0026] In the embodiment shown, the electro-pyrotechnic device 2 comprises, in addition to the electro-pyrotechnic igniter 21 and the piston 23, an actuating housing 22 arranged to interface with the valve housing 3. This embodiment allows the electro-pyrotechnic device 2 to be mounted on a standard safety valve 1, which is not equipped with an active mode according to the invention. Alternatively, the valve housing 3 can be specifically designed to directly receive the pyrotechnic device 2 without an actuating housing 22, thus further reducing the number of parts. When the safety valve 1 includes an actuating housing 22, the following two assembly options can be considered: - the actuator housing 22 is assembled to the valve housing 3 before the assembly of the piston 23 and the electro-pyrotechnic igniter 21, or - the piston 23 and the electro-pyrotechnic igniter 21 are assembled to the actuating housing 22 to form an actuating sub-assembly which can then be assembled onto the valve housing 3.

[0027] The safety valve 1 is arranged to operate in an active or passive mode.

[0028] In passive mode, when a predetermined temperature is reached, the breakable bulb 42, for example made of glass, breaks under the pressure or expansion of the liquid 4L. The temperature outside the safety valve 1 is transmitted to the liquid 41 via the exchange orifice 5. Once broken, the breakable bulb 42 no longer supports the shut-off slide 6, which can translate (upwards in [Fig. 1]) under the effect of the pressure present in the transfer channel 8 and thus free the passage between the transfer channel 8 and the drain channel 7.

[0029] In active mode, when an electrical ignition signal is applied to the electro-pyrotechnical device 2, and in particular to the electro-pyrotechnical igniter 21, via at least one of the connecting pins 210, pressure or force is applied to the piston 23 (directly or indirectly), causing the piston 23 to move towards the frangible bulb 42 (i.e., downwards in [Fig. 1]), thereby breaking the frangible bulb 42. Once the frangible bulb 42 is broken, as in passive mode, the sealing slide 6, no longer supported, can translate (upwards in [Fig. 1]) under the pressure present in the transfer channel 8, thus opening the passage between the transfer channel 8 and the drain channel 7. The state of the safety valve 1 after operation in active mode is shown in the [Fig.2]. The electro-pyrotechnic igniter 21 in this embodiment can be sealed (i.e., does not release gas) or can generate and release gases. In the first case, the electro-pyrotechnic igniter 21 is arranged to deform, in particular to expand or inflate according to the direction of movement of the piston 3, and it is therefore the electro-pyrotechnic igniter 21 that directly moves the piston 23. In the second case, it is the gases produced and released by the electro-pyrotechnic igniter 21 that move the piston 23.

[0030] It is understood that, according to the present invention, an electro-pyrotechnic igniter 21 is a device comprising at least one connecting pin 210, at least one pyrotechnic material, at least one casing containing said at least one pyrotechnic material, and at least one ignition element (typically a resistive bridge) connected to said at least one connecting pin 210 and arranged to ignite the pyrotechnic material. A protective cap may be added to these elements, particularly when the casing is made of a metallic material.

[0031] The embodiment shown in [Fig. 3] is similar to that shown in [Fig. 1] except that it does not include a piston. The elements common to both embodiments will not be detailed further.

[0032] In the embodiment of [Fig. 3], the electro-pyrotechnic igniter 21 directly contributes to holding the thermal release element 4. As in the previous embodiment, the electro-pyrotechnic igniter 21 may or may not be sealed. This embodiment further reduces the overall size of the safety valve 1 and its number of parts. In this embodiment, it may be advantageous for the electro-pyrotechnic igniter 21 to include a protective cap whose shape conforms to part of the shape of the thermal release element 4 to optimally hold or secure it. Industrial application

[0033] A safety valve according to the present invention, and its manufacture, are capable of industrial application.

[0034] It will be understood that various modifications and / or improvements, obvious to those skilled in the art, can be made to the different embodiments of the invention described herein without departing from the scope of the invention. In particular, the sealing slide can be replaced by a shim arranged to break under the pressure present in the transfer channel when it is not supported by the thermal release element. Furthermore, other types of thermal release element can be considered.

Claims

Demands

1. Safety valve (1) for a pressure device comprising: - a valve housing (3) arranged to connect the safety valve (1) to the pressure device, - a transfer channel (8) arranged to be in fluidic communication with the pressure device, - a drain channel (7), - a sealing element (6) arranged to seal the transfer channel (8) when it is in a sealed state and arranged to allow free passage between the transfer channel (8) and the drain channel (7) when it is in a drained state, - an electro-pyrotechnic device (2), - a thermal release element (4) arranged to maintain the sealing element (6) in the sealed state below a predetermined activation temperature and to allow free passage of the sealing element (6) above the activation temperature,characterized in that the thermal release element (4) is arranged between the sealing element (6) and the electro-pyrotechnic device (2) such that the electro-pyrotechnic device (2) participates in maintaining the sealing element (6) in the sealed state.

2. Safety valve (1) according to claim 1 wherein the sealing element (6) is a slide or a frangible element.

3. Safety valve (1) according to any one of the preceding claims wherein the thermal release element (4) is a thermal bulb arranged to rupture beyond the predetermined activation temperature.

4. Safety valve (1) according to any one of the preceding claims wherein the valve housing (3) comprises at least one exchange port (5) separate from the drain channel (7) and the transfer channel (8) and arranged to bring the thermal release element (4) into fluidic communication with the external environment of the safety valve (1).

5. Safety valve (1) according to any one of the preceding claims wherein the electro-pyrotechnic device (2) comprises or is an electro-pyrotechnic igniter (21) arranged in direct contact with the thermal release element.

6. Safety valve (1) according to any one of claims 1 to 4 comprising: - a piston (23) arranged movable between a rest position and an activated position, - the electro-pyrotechnic device (2) is an electro-pyrotechnic igniter (21) arranged to move the piston (23) from the rest position to the activated position on an electrical ignition pulse.

7. Safety valve (1) according to the preceding claim wherein the piston (23) is in direct contact with the thermal release element (4).

8. Safety valve (1) according to any one of the preceding claims wherein the electro-pyrotechnic device (21), the thermal release element (4) and the sealing element (6) are arranged coaxially along an electrical connection pin axis (210) of the electro-pyrotechnic device (2).

9. Safety valve (1) according to any one of claims 1 to 8 wherein the thermal release element (4) and the sealing element (6) are arranged coaxially along a drain axis distinct from an electrical connection spindle axis (210) of the electro-pyrotechnic device (2).

10. Safety valve (1) according to any one of the preceding claims wherein the electro-pyrotechnic device (2) comprises an actuation housing (22) arranged to interface with the valve housing (3).

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