FR2951799A1 - GAS RESERVOIR VALVE - Google Patents

Abstract

Valve (1) comprising a body (4), means (5) for fixing to the tank, at least one gas channel (7, 8), a thermal safety device (9) for opening the valve (1) from a body (10) arriving at a predefined temperature. The valve (1) has a resilient element (13) at least partly made of plastic material which applies a force on the piston (12) to move the piston (12) from its closed position to its open position. The piston (12) at least partly of elastic material is in direct contact with the valve body (4) at the first gas channel (7) so that the elastic plastic material of the piston (12) provides a function of seal.

Description

FIELD OF THE INVENTION The present invention relates to a gas tank valve, in particular a natural gas tank valve fitted to a motor vehicle comprising a valve body, a means for fixing to the gas tank, at least one gas channel. realized in the valve body to conduct the gas to the gas reservoir and at the outlet of the gas tank, a thermal safety device for opening the subpape from a body arriving at a predetermined temperature, and which changes form from this predefined temperature, a piston movable between a closed position and an open position to close or open a first gas channel held in the closed position by the body and released from the body from the predefined temperature to that the piston is movable from its closed position to its open position. The invention also relates to a gas reservoir equipped with such a valve. STATE OF THE ART Gas tanks are used for the most diverse technical applications for receiving and storing gas. For example, motor vehicles use natural gas tanks to store natural gas as fuel for the engine of the motor vehicle. Gas tanks are equipped with valves to introduce gas into each tank and divert gas from the tank. The valve also has a safety function. A thermal safety device opens the valve from a predefined temperature, for example 110 ° C, to prevent the gas tank from exploding. In addition, the valves are generally also provided with overpressure safeties to empty the gas tank from a preset pressure, for example of the order of 300 bar. The valve has a valve body for closing the gas reservoir. The channels machined in the valve body allow the gas to be introduced or removed from the gas tank. DE 103 61 781 A1 discloses an electromagnetic valve for a gas cylinder, especially a gas cylinder for motor vehicles. The valve has a

2 valve body, a threaded segment on the valve body engaged with an external thread which is screwed into the internal thread of the gas cylinder and a shutter body segment penetrating the gas cylinder and a piston of external stop as well as movable electromagnetic control elements with the locking piston from a running position to a closed position. DESCRIPTION AND ADVANTAGES OF THE INVENTION The invention relates to a gas tank valve of the type defined above, characterized in that the valve has an elastic element made at least partially of plastic material which applies a force to the piston to move it from its closed position to its open position, and / or the piston is at least partly made of elastic material and the elastic material is in direct contact with the valve body at the first gas channel so that the plastic material - elastic tick of the piston ensures a sealing function. Thus the valve according to the invention for a gas tank, including a valve for a natural gas tank of a motor vehicle, comprises a valve body, a means for example a thread or a bayonet type connection to be fixed to the tank at least one gas channel formed in the valve body for evacuating gas to the gas reservoir and from the gas reservoir; a thermal safety device is provided for opening the valve from a predefined temperature, comprising a body which, from the predefined temperature, changes shape. A piston movable between a closed position and an open position, serving to close and open a first gas channel, is held in the closed position for the body and from the predetermined temperature it is released and moves from its closed position at its open position; the valve comprises an elastic element at least partly of plastics material and with the aid of this elastic element, a force is applied to the piston to move the piston from the closed position to the open position and / or to that the piston composed at least in part of elastic plastic material, and the elastic plastic material in direct contact with the valve body are applied against the first gas channel; the elastic plastic material of the piston ensures a function

3 sealing especially between the piston and the valve body according to the first gas channel. The piston is any shutter member for opening and closing the first gas channel; it can for example also be realized as closing nozzle, as shutter or as a drawer. The elastic element is preferably completely made of plastic. Due to its embodiment, an elastic plastic material, preferably rubber, the elastic member provides the sealing function between the piston and the valve body at the first sealing channel. This avoids the introduction of dirt and particles into the volume between the piston and the valve body at the first gas channel. According to another development, the first elastic member serves as a seal avoiding the penetration of dirt or particles in the gap between the piston and the valve body at the first gas channel. In a complementary manner, the elastic element is in the form of a ring surrounding the piston. As the elastic element completely surrounds the piston, this allows complete protection against the ingress of dirt. Preferably, the elastic element has an outer con-turn of undulating shape. The corrugated outer contour increases the elastic properties of the elastic element and makes it possible to apply greater prestressing and thus to exert a greater thrust force starting from the elastic element towards the piston and / or the body of the elastic element. valve. Due to the forces exerted between the elastic element and the piston as well as the valve body, the sealing function is increased at the bearing surfaces of the elastic element on the piston and / or the valve body.

According to a variant, the piston is at least partly completely made of metal, for example steel or aluminum, and between the piston and the piston body, there is a seal, in particular an O-ring. The seal including the O-ring is made of an elastic plastic material, preferably rubber.

The piston is in particular of metal and a metallic plastic material; the metal is connected in particular by a connection in form to the plastic material and / or preferably the plastics material has, on the outside, on the piston, for example a plastic piston. Advantageously, the piston at least partly made of plastic material has a corrugated outer contour to improve the sealing function of the piston. Thanks to the undulating outer contour, the piston is applied in the region of the outer contour against the first gas channel and this annularly on the valve body. The contact ring is nevertheless exposed to a large thrust related to the elastic preload of the piston in the first gas channel so that there is thus a very developed sealing effect.

According to another embodiment, the piston which consists at least in part of plastic material has a stop for dirty-tees, to prevent the entry of dirt or particles between the piston and the valve body at the first channel gas. In particular, the dirt holding stop in the receiving chamber of the valve body is designed for this body and preferably the retaining stop is fully pressed against the valve body in the receiving chamber. According to another development, the piston is displaced by the pressure of the gas from the reservoir, from its closed position to its open position, by the pressure of the gas acting on the reservoir, preferably directly on the piston. The piston is thus in direct contact or in fluid connection with the gas of the reservoir so that the pressure of the gases acts on the piston. The elastic element which has moved the piston during bursting of the body, in addition in the direction of the opening position, provides the prestressing function of the body itself without significant pressure of gas applied to the valve, for to guarantee the maintenance of the body during the transport. In addition the first gas channel must be released as soon as only low pressure prevails in the gas tank. When the preset temperature is reached, for example of the order of 80 ° C. to 120 ° C., in particular close to 110 ° C., the body changes shape so that the piston can move from its closed position to its opening position very quickly. If the gas pressure in the tank is not large enough, the force required to move the piston from the closed position to the open position can be applied by the resilient member. This ensures that even for a low pressure in the gas tank, when the preset temperature is reached, the thermal safety device opens the valve. According to a complementary variant, the valve body comprises a second gas channel equipped with a gas valve, preferably electromagnetic, installed in the second gas channel to introduce gas into the gas tank, to fill the gas tank. and for evacuating gas from the tank to empty the tank under normal operating conditions, for example for supplying the combustion engine of the motor vehicle. The electromagnetic gas valve serves to fill and empty the gas tank in normal operating situations. When using natural gas, it is for example necessary to fill the gas tank in a station supplying natural gas. The gas valve in the sewer channel opens and allows the gas to enter. During taxiing, the valve must be open so that the gas tank feeds the engine of the motor vehicle. According to another feature, the body is a glass body filled with liquid that breaks from a predefined temperature. For example, the glass body is a bulb that is filled with liquid. According to another development, the valve body is made of metal, in particular steel or aluminum. According to the invention, the tank is equipped with a valve in particular for receiving natural gas supplying the vehicle; the valve is made as the valve described above. According to another development, the valve is equipped with an overpressure safety device to empty or open the gas tank from a predefined pressure.

Advantageously, the overpressure safety device comprises a disk that can break from a predefined pressure, for example between 200 and 400 bar and in particular for about 300 bar. Preferably, the pressure of the gas is directly applied to the bursting disc. Drawings The present invention will be described in more detail below with the aid of exemplary embodiments shown schematically in the accompanying drawings in which: - Figure 1 is a perspective view of a gas tank valve, FIG. 2 is a longitudinal section of the valve equipped with a thermal safety device according to a first exemplary embodiment, FIG. 3 is a detailed view of the thermal safety device according to FIG. 2, FIG. 2 is a detail view of the thermal safety device corresponding to a second embodiment, FIG. 5 is a detailed view of the piston of the thermal safety device of FIG. 4, FIG. 6 is a longitudinal section of FIG. valve in the gas tank, - Figure 7 is a greatly simplified view of a vehicle. DESCRIPTION OF EMBODIMENTS OF THE INVENTION A valve 1 according to FIGS. 1 and 2 serves to close a gas tank 2 constituted by a natural gas tank 3 (FIG. 6) for a motor vehicle 30 (FIG. 7). The valve 1 comprises a body 4 with a means 5 for attachment to the gas tank 2. The means 5 is in the form of a thread 6. The thread 6 is an external thread on the valve body 4 and which is screwed into a not shown internal thread of the natural gas reservoir 3 and thus attaches to the natural gas reservoir 3. Alternatively, the means 5 for attaching the valve 1 to the gas reservoir 2 may be a type connection bayonet (not shown). The valve body 4 further comprises grooves 21 for receiving the not shown seals. The

7 seals not shown to seal the volume between the valve 1 and the gas tank 2. The poppet 1 is introduced in part into the receiving nozzle of the gas tank 2.

The valve 1 comprises a first gas channel 7 machined in the valve body 4 and a second gas channel 8 also machined in the valve body 4. The second gas channel 8 (Figure 2) is used to fill and empty the gas tank 2 under normal operating conditions. For this purpose, an electromagnetically controlled gas valve 20 makes it possible to close and open the second gas channel 8. A flow restrictor 29 avoids large flows of gas in the second channel 8. The flow limiter 29 is necessary to that if the gas tank 2 with the valve 1 equips a motor vehicle 30, in case of leakage or rupture of unrepresented connecting lines from the valve 1, the gas tank 2 supplying the engine of the motor vehicle 30 will not be emptied in a very short time because high gas flows are a security risk. The valve 1 further comprises a thermal safety device 9. The function of the thermal safety device 9 is to release the first gas channel 7 from a predefined temperature. This allows the gas from the tank 2 to escape through the first gas channel 7 when a preset temperature is reached. This is necessary for reasons of safety because, for example, in the event of a fire of the vehicle 30, high temperatures will be even at the level of the gas tank 2, so that the thermal safety device 9 makes it possible to empty the tank gas 2 from the preset temperature, to prevent the explosion of the gas tank 2. The preset temperature is for example in a range between 80 ° C and 120 ° C and in particular the preset temperature is close to 110 ° C. The thermal safety device 9 (FIGS. 2 and 3) comprises a member 10 constituted by a glass body 11. The glass body 11 (also called a bulb) is filled with a liquid. The glass body 11 is held at its upper end by a nut 22. The lower end of the glass body 11 is locked or held by a piston 12. According to the first embodiment shown in FIGS.

8 gures 2 and 3, the piston 12 is aluminum. The aluminum body 4 comprises a chamber 19, machined. The receiving chamber 19 is equipped with a nut 22 fixed by its not shown thread of the valve body 4. The chamber 19 receives the glass body 11 and in part the piston 12. The piston 12 placed partly in the first gas channel 7 and the lower end of the piston 12 comprises a spindle of cylindrical shape 31. The spindle of cylindrical shape 31 is surrounded by a rubber seal 16 consisting of an O-ring 17 to seal the fluid of the first gas channel 7 when the piston 12 occupies its closed position shown in Figures 2 and 3. A bearing ring 32 of the cylindrical pin 31 further supports the O-ring 17. The upper end of the piston 12 comprises a widening The disc-shaped enlargement 33 of the pis-ton 12 and the valve body 4 at the lower end of the chamber 19 has a resilient element 13 of elastic material, especially of rubber. The elastic element is in the form of a ring or ring 15 completely surrounding the piston 12. The elastic element 13 is tightened with elastic preload between the disc-shaped extension 33 of the piston 12 and the lower end the housing 19 against the valve body 4 so that the elastic member 13 exerts a thrust on the piston 12, directed upwardly according to the representation of Figures 2 and 3. The glass body 11 is clamped by the piston 12 with an elastic pretension between the nut 22 and the piston 12. The glass body 11 can thus be secured and secured to the valve 11 even in the absence of gas pressure in the tank 2. When Valve 1 level has temperatures above the preset temperature, for example temperatures above 110 ° C, the glass body 11 breaks under the effect of the liquid it contains. The thrust exerted by the elastic element 13 on the piston 12 and the pressure of the gases acting on the piston 12 in the first gas channel 7 move the piston 12 from the closed position (FIGS. 2 and 3) in a opening position (not shown). When the pis-ton 12 is in the open position, the first gas channel 7 which de-mouth in the chamber 19 is no longer closed by the piston 12. The gas reservoir 2 can thus arrive directly in the chamber 19 and

9 to escape through it, outwardly through the exit holes 23 (Figure 3). The natural gas tank 3 of the motor vehicle 30 is subjected to a high pressure, for example of the order of 300 bars, before the complete emptying of the gas tank 3. When the natural gas tank 3 contains only one small amount of natural gas, there is in the tank 3 a very low pressure, for example of the order of a few bars. Advantageously, the elastic element 13 applies the force required to move the piston 12 from the closed position to the open position, even with a natural gas reservoir 3 with very low filling and low thrusts of the natural gas on the piston 12 for a preset temperature of the piston 12, to move it from its closed position to its open position, despite the friction. The elastic member 13 further serves as a dirt retaining ring 18. The elastic member 13 or the dirt retaining ring 15 is installed with resilient preload between the disk-shaped extension 33 of the piston 12 and the valve body 4 at the lower end of the housing 19. Under the effect of the thrusts produced between the elastic element 13 and the piston 12 as well as the valve body 4, the sealing element 13 seals the first gas channel 7 vis-à-vis the receiving chamber 19 so that under these conditions, there is no risk of the penetration of dirt or particles in the first gas channel 7 in the area between the piston 12 and the first gas channel 7, particularly in the region of the O-rings 17. This ensures the operation of the valve 1 permanently. In addition, the elastic properties of the elastic element 13 also advantageously compensate for the manufacturing inaccuracies of the piston 12, the glass body 11 and the receiving chamber 19. FIGS. 4 and 5 show a second embodiment of the invention. In the following, the main differences will only be described in relation to the first embodiment given in FIG. 1. The piston 12 is made of an elastic material or plastic material, preferably of rubber. The piston 12 housed in both the first gas channel 7 and 35 in the receiving chamber 19 also functions as a seal

Io to ensure the direct sealing of the first gas channel 7. The piston 12 has under these conditions an undulating outer contour 28 in the segment into which the first gas channel 7 is introduced. The piston 12 which, in addition to the embodiment rubber, may be in a combination of rubber and metal, that is to say a piece of metal / rubber, has at its lower end a guide ramp 27. The guide ramp 27 facilitates the introduction of the piston 12 in the first gas channel 7. The corrugated outer contour 28 of the piston 12 improves the sealing effect of the piston 12 in the first channel 7. In order for the piston 12 to be introduced only for a predetermined length in the first gas channel 7, a shoulder 26 limits the length of introduction of the piston 12 into the first gas channel 7. A retaining stop 25 of the piston 12 is completely peripherally applied against the body of the piston. valve 4 at the chamber receiving station 19 (FIG. 4). The holding stop 25 prevents dirt or particles from entering the area between the first piston 12 and the valve body 4 at the level of the first gas channel 7. This ensures reliable operation at all times. The dirt can not block the movement of the piston 12 from its closed position shown in FIGS. 4 and 5 to its open position and cause leaks in the closed position. A central cavity 24 receives the glass body 11. The glass body 11 is elastically clamped between the nut 22 and the elastic piston 12 to be reliably held in the receiving chamber 19. Despite the pressure variations in the gas tank 2, for example at the time of filling or when sampling gas from the gas tank 2, the glass body 11 is held safely in the receiving housing 19. If the temperature of the valve rises to at the preset temperature of 110 ° C, as in the first exemplary embodiment, the glass body 11 breaks. Under the effect of the gas pressure acting on the piston 12 by the first gas channel 7, the piston 12 is raised from its closed position (Figure 4) in its open position not shown. The first gas channel 7 is no longer in these conditions closed by the elastic piston 12 so that the gas can

11 to escape directly through the first gas channel 7 into the receiving chamber 19. The gas arriving in the receiving chamber 19 then escapes outwards through the exit bores 23. The exit bores 23 open out in unrepresented gas channels which terminate on their side, outside the valve 11. The details of the various embodiments can be combined to the extent that nothing opposes it. Overall, the valve 1 according to the invention and the gas tank according to the invention have very important advantages.

The penetration of dirt or particles into the region of the piston 12 installed in the first gas channel 7 can be reliably and reliably avoided. This ensures the reliability of the operation of the thermal safety device 9 even over extended periods in the motor vehicle 30. In addition, the valve 1 is of a compact construction.20 NOMENCLATURE 1. Valve 2. Gas tank 3. Fuel tank natural gas 4. Valve body 5. Fixing means 6. Thread 7. First gas channel 8. Second gas channel 9. Safety device 10. Body 11. Glass body / bulb 12. Piston 13. Elastic element 15 Ring 16. Rubber seal 17. O-ring 18. Retaining ring 19. Receiving chamber 20. Gas valve 21. Groove 22. Nut 23. Exit bore 24. Center recess 25. Retaining edge 26. Shoulder 27 Inlet boom 28. Outer corrugated contour 29. Flow restrictor 30. Motor vehicle 31. Cylindrical spindle 32. Support ring 33. Disc-shaped enlargement 30

Claims (1)

CLAIMS 1) Gas valve (1) (2) including valve (1) natural gas tank (3) fitted to a motor vehicle (30) comprising - a valve body (4), - means (5) for fixing to the gas tank (2), - at least one gas channel (7, 8) provided in the valve body (4) for conducting the gas to the gas tank (2) and at the outlet of the gas tank (2), - a thermal safety device (9) for opening the valve (1) from a body (10) arriving at a predetermined temperature, and which changes shape from this predefined temperature, a piston ( 12) movable between a closed position and an open position to close or open a first gas channel (7) held in the closed position by the body (10) and released from the body (10) from the predefined temperature for the piston (12) to move from its closed position to its open position, valve characterized in that - the valve (1) has a resilient element (13) made at least partly of plastic material which applies a force to the piston (12) to move it from its closed position to its open position, and / or - the piston (12) is at least partly of elastic material and the elastic material is in direct contact with the valve body (4) at the first gas channel (7) for the elastic plastic material of the piston (12) to provide a sealing function. 2 °) valve according to claim 1, characterized in that the elastic element (13) is completely plastic. Valve according to claim 1, characterized in that the elastic element (13) is a dirt-retaining seal (14) for preventing the penetration of dirt or particles into the space between the piston (12). ) and the valve body (4) at the first gas channel (7) 4 °) Valve according to claim 1, characterized in that the elastic element (13) is in the form of a ring surrounding the piston (12). 5 °) valve according to claim 4, characterized in that the elastic element (13) has a corrugated outer contour. 6 °) valve according to claim 1, characterized in that the piston (12) is at least partly and in particular completely made of metal, for example steel or aluminum and a seal (16) in particular a ring annular ring (17) is installed between the piston (12) and the valve body (4). 7 °) valve according to claim 1, characterized in that the piston (12) at least partly made of elastic plastic material has an outer contour (28) of corrugated shape to improve the sealing function of the piston (12). 8 °) valve according to claim 1, characterized in that the piston (12) at least partly made of plastic material comprises a dirt retaining stop (25) to prevent the penetration of dirt or particles between the piston (12) and the valve body (4) at the first gas channel (7). Valve according to claim 8, characterized in that the retaining stop (25) is formed in the receiving chamber (19) of the valve body (4) for the body (10) and preferably the retaining stop (25) is completely peripherally applied to the valve body of the receiving chamber (19). 10 °) valve according to claim 1, characterized in that the piston (12) is movable by the pressure of the gas (2) to be moved from its closed position to its open position by the pressure of the gas tank to gas preferably applied directly to the pis-ton (12). Valve according to Claim 1, characterized in that a second gas channel (8) is formed in the valve body (4) and the second gas channel (8) comprises a gas valve (20) of electromagnetic preference, for introducing the gas into the gas tank (2) during the filling of the tank (2) and for evacuating the gas from the gas tank (2) when a gas level is reached at the emptying of the tank which corresponds to in the normal operating state. Valve according to claim 1, characterized in that the body (10) is a glass body (11) filled with fluid, which breaks for a temperature above a defined temperature. 13 °) valve according to claim 1, characterized in that the valve body (4) is made of metal, in particular steel or alumi-nium. 14 °) tank (2) of vehicle (1) including a gas tank for receiving natural gas for a vehicle (30), characterized in that the valve (1) of the gas tank (2) is made according to a or more than one of the above claims.