Device for discharging gas

Abstract

Device for discharging gas which was stored under high pressure in a compressed gas container (6) and which flows out of the latter via a safety valve or a drain valve via an outflow opening, comprising a blow-off line (12) which connects the outflow opening to an area in the vicinity of the compressed gas reservoir (6), wherein the blow-off line (12) is closed on its side facing away from the outflow opening by a closure element (15) which opens when gas flows, wherein the closure element (15) has a cover (17) which is in latching engagement with an opening (22) in a base body (16) of the closure element (15), which opening is connected to the interior of the blow-off line (12), wherein the base body (16) has latching elements (19) which interact in a latching manner with recesses (20) in the blow-off line (12), characterized in that the recesses are designed as a groove (20) in the blow-off line (12).

Description

The invention relates to a device for discharging gas according to the type defined in more detail in the preamble of claim 1.Devices for discharging gas from compressed gas containers are known from the general prior art. Typically, pressurized gas containers, for example pressurized gas containers for storing hydrogen at a nominal pressure of 700 bar, in particular in a fuel cell vehicle, have safety devices in order to blow off the pressurized gas in the event of an overpressure. The safety devices can be equipped, for example, with melting fuses or safety devices which open when the temperature is increased, with burst glass vials or the like. A manual drain valve may also be present. Typically, all these possibilities for blowing gas from the compressed gas container open into the region of an outflow opening, for example in a valve housing. From the outflow opening, a blow-off line, which is also frequently referred to as the English term vent line or vent tube, then typically leads into a region in which the gas can be discharged non-critically. In the above-mentioned example, in which the gas is discharged from a compressed gas storage for hydrogen in a fuel cell vehicle, the discharge line can lead, for example, into the region of the underbody of the vehicle. In this region, the gas, in this case the hydrogen, can be discharged comparatively non-critically.It is now problematic, in particular when used in vehicles, if spray water or in particular water, which penetrates into the blow-off line during cleaning of the vehicle in a washing installation with high-pressure underground cleaning or manually with a high-pressure cleaner, penetrates. This can lead to corrosion and, if appropriate, to impairment of the safety devices in the region of the compressed gas container or its valve.From the general prior art, solutions are known which can be used in particular for upwardly directed blow-off lines. Solutions of this type are described, for example, in U.S. Pat. No. 5,267,894 A or similarly also in DE 102 00 281 A1. The closures serve, as mentioned in the German laid-open specification, in particular to prevent rain from entering. The U.S. Pat. No. describes a structure for this purpose which is of very complex design and which ensures, via balances, that a flap is normally closed by the force of gravity, which flap is then only pushed open by the gas flowing out. This construction is extremely complex, complicated and expensive and can thus only be used in the described manner in an upwardly discharging blow-off line. However, blow-off lines, in particular when used in vehicles, frequently lead to below the vehicle, so that use is not possible here.DE 10 2011 114 725 A1 discloses a compressed gas container having a valve device which has a safety device, having a trigger line which is arranged in at least one selected hazardous area surrounding the compressed gas container, wherein the safety device is at least indirectly actuated by a pressure change on the trigger line and then connects the interior of the compressed gas container to the environment.DE 295 18 905 U1 discloses a container with a removable lid that seals the container in a sealed manner, wherein a latching connection is provided, which connects the lid to the container in a form-fitting and non-separable manner.The object of the present invention is to provide a gas discharge device according to the preamble of claim 1, which is improved over the prior art and which avoids in particular the said drawbacks.According to the invention, this object is achieved by a device having the features in the characterizing part of claim 1. Advantageous embodiments and further developments of the concept are evident from the dependent claims dependent thereon. Claim 8 also specifies a preferred use of the device according to the invention.In the device according to the invention, it is such that the side of the blow-off line facing away from the outflow opening has a closure element which opens in the event of a gas flow. This is provided with a cover which is in locking engagement with an opening in a base body, wherein the opening in the base body of the closure element is connected to the interior of the blow-off line. In the device according to the invention, the closure element thus securely and reliably closes the blow-off line by a cover which is snapped into the opening. If gas escapes, this cover is pressed open by the overpressure present despite the snap-in connection, and the gas can escape through the opening in the base body of the closure element. In the preferred use on a compressed gas container in which hydrogen is stored at a nominal pressure of 700 bar, an overpressure of the order of magnitude of approximately 15 bar prevails in each case, even in the case of an empty container, when gas flows out through the blow-off line. This overpressure is sufficient to reliably release the cover from the opening into which it is snapped and thus to open up a flow path for the gas. On the other hand, the snapped-on cover can resist comparatively strong loads from the outside, since the snap-on cover in the opening of the base body produces a comparatively secure connection of the cover, which in the normal case cannot be lifted from the base body even by a high-pressure radiator or an underbody cleaning of a vehicle with high pressure in a washing installation. This ensures a secure and reliable closure against the penetration of water by means of the closure element and, on the other hand, in the case of a outflowing gas, the latter opens reliably in order to release a large flow cross section for the outflowing gas.In the device according to the invention, it is also provided that the base body has latching elements which interact with recesses in the blow-off line in a latching manner. During assembly, it can then be very easily plugged onto the end of the blow-off line and locks with it. Further sealing measures are typically not necessary, since there is sufficient tightness against the penetration of water, and since in the case of a blowing off of gas, possible leaks with respect to the gas are not critical.In a very advantageous development of the device according to the invention, it is now that the cover is connected to the base body via a film hinge. In particular, such a construction, in which the cover is connected to the base body via a film hinge, is extremely simple to produce. For example, the base body and the cover can be realized in one piece from a plastic material, preferably an antistatic plastic material, for preferred use in a motor vehicle. They can then be produced simply, for example, by an injection molding process. The film hinge prevents the cover from flying away from the closure element in the manner of a projectile when gas flows out via the blow-off line. This represents an additional safety advantage.According to an advantageous refinement, the plastic material can be embodied in particular as antistatic. This is of decisive importance above all when used in a motor vehicle, so that spark formation in this region is reliably and reliably prevented, thereby reducing the risk that the gas stream which is discharged to the environment through the blow-off line ignites. This is a considerable safety advantage, especially in the case of hydrogen.According to an advantageous development, the cover can be designed to be completely planar on the side facing away from the outflow opening. Such a completely planar cover does not offer any possible attack for example for the jet of a high-pressure cleaner, so that the risk of the cover being moved out of the position locked in the opening in such a case is reduced even further.As already mentioned several times, the device according to the invention can be used in particular in the field of compressed gas accumulators which are used in vehicles for storing hydrogen or compressed natural gas. The corresponding advantages can be achieved especially for this application, since large numbers are to be expected for this purpose. The very simple and cost-effective construction and the correspondingly simple assembly are therefore a decisive advantage. In addition, in such an application, special requirements are to be placed on the safety, which requirements can be fulfilled without problems by the device according to the invention. Here too, it has decisive advantages over the embodiments according to the prior art, in particular since it is particularly resistant, for example, to penetrating water of washing installations and high-pressure cleaners, which are very frequently used as cleaning agents in the field of vehicles.Further advantageous embodiments of the device according to the invention are also evident from the further dependent dependent claims and become clear on the basis of the exemplary embodiment which is described in more detail below with reference to the figures.The following are shown: FIG. 1 shows a fuel cell vehicle, indicated by way of example, having a compressed gas container for hydrogen; FIG. 2 is a sectional view through one end of the blow-off line in the vehicle; FIG. 3 shows the end of the blow-off line with the closure element in cross section; and FIG. 4 shows the closure element in the opened state, analogous to the illustration in FIG. 4.The device according to the invention is explained and described in more detail below with reference to an exemplary embodiment and application in a fuel cell vehicle having a hydrogen tank which is provided with the device according to the invention. The device according to the invention can be used equally well for vehicles which are driven, for example, by hydrogen or compressed natural gas by means of an internal combustion engine. The device according to the invention can also be used outside a vehicle, but has its preferred application in the field of vehicles because of its compact design and ease of assembly and because of the very secure embodiment.The illustration in FIG. 1 shows a very highly schematic representation of a vehicle 1 which is supplied with electrical drive power via a fuel cell 2. The fuel cell 2 comprises a cathode region 3, to which air is supplied as an oxygen supplier, and an anode region 4, to which hydrogen is supplied from a storage device 5 for storing hydrogen under high pressure. By way of example for the entire storage device 5, which is typically formed from various piping, valve devices, a tank connection and one or more compressed gas containers 6, only one of the compressed gas containers 6 is indicated in the illustration of FIG. 1. This is connected via a hydrogen line 7 to the anode space 4 of the fuel cell 2, wherein pressure control and metering units and the like are typically arranged here. The fuel cell 2 supplies electrical power, which is appropriately conditioned via power electronics 8 and is passed on to a traction motor 9, which is indicated in principle and then serves to drive the vehicle 1.It is now the case that, in particular when storing hydrogen in the storage device 5 or its at least one compressed gas container 6, nominal pressures in the order of magnitude of 700 bar are now generally known and customary, wherein higher pressure levels are also already envisaged. In the event of an accident of the vehicle 1, a considerable risk now originates from such a storage device 5 or its compressed gas containers 6, for example if the storage device 5 is heated very strongly by a fire. In the worst case, an explosion may occur.In order to counteract this principle risk, it is generally known and common for safety valves to be arranged in the storage device 5 or in the region of the compressed gas containers 6. In general, each compressed gas container 6 has at its one end a connecting piece with a valve device, for example a so-called on tank valve (OTV), which is connected to the hydrogen line 7. In the area of this valve device, the safety valve mentioned is arranged in a manner known per se. This is connected via an outflow opening to a blow-off line 12 which ensures that, in the event of the safety valve responding, the hydrogen is blown off in a targeted manner in order to pass as quickly as possible from the zone in which the passengers are, in order thus to reduce the risk of fire or explosion if ignitable mixtures should form. The blow-off line 12 can be connected to one or, if present, to a plurality of compressed gas accumulators 6 of the storage device 5.In the illustration of FIG. 2, the end of the blow-off line 12 facing away from the outflow opening and the compressed gas container 6 can be seen. In the illustration of the figure, this end of the blow-off line 12 is bent away counter to the direction of travel denoted by F, that is to say towards the rear in the direction of travel, and ends above an opening 13 in an underbody cladding 14 of the vehicle 1. Again at an angle of 45° to this axis A, the end of the blow-off line 12 is cut off and provided with a closure element 15 indicated in the figure, which will be discussed in detail later. The blow-off line 12 can additionally be provided with a thermal insulation, which is not shown here.The illustration of FIG. 3 shows the closure element 15 mentioned. It essentially consists of a base body 16 and a cover 17 which is connected to the base body 16 via a film hinge 18. The closure element 15 is designed such that it matches the end contour of the blow-off line 12 cut off obliquely to the axis A and securely closes it. The closure element 15 can be manufactured in one piece from a plastic, in particular from an antistatic plastic, for example by an injection molding method or the like. It has latching elements 19, which can also be seen very well in particular in the three-dimensional sectional illustration of FIG. 4. The latching elements 19 are designed such that they can latch correspondingly into a circumferential groove 20 in the blow-off line 12. The closure element 15 can thus be simply plugged onto the cut-off end of the blow-off line 12. During assembly, the latching elements 19 then latch with the circumferential groove 20 and the closure element 15 securely holds at the end of the blow-off line 12.In the illustration of FIG. 3, the closed state is illustrated. The cover 17, which is completely smooth toward the outside, i.e., toward the bottom in the illustration of FIG. 3, has latching elements 21 on its inside, via which it is latched to an opening 22 of the base body 16 of the closure element 15. This represents the locked state of the locking element 15. Due to the smooth surface of the cover 17, it is relatively smooth, also for example for high-pressure cleaners or the like, so that they cannot engage accordingly and open the cover 17 unintentionally. It thus maintains and seals securely and tightly in the opening 22 under all likely situations. Only when gases emerge through the interior of the blow-off line 12 is the cover 17 pressed out of the opening 22 by the overpressure despite the latching elements 21, so that the open state of the closure element 15 shown in FIG. 4 is established. In this open state of the closure element 15, the gas can flow out to the environment through the blow-off line 12 and the closure element 15 or its opening 22 with low flow resistance.At the rated pressure of 700 bar in question, minimum pressures of the order of magnitude of 15 bar also occur in the case of an "empty" storage device 5. If a safety-relevant discharge of gas occurs via the discharge line 12, a pressure of at least 5 bar or more prevails in its interior, which pressure is sufficient without problems to open the cover 17, even if the latter is locked comparatively firmly in order to reliably and reliably seal the discharge line 12 against high-pressure cleaners and other adverse effects which are present on the closure element 15 from the outside.

Claims

Device for discharging gas which was stored in a compressed gas container (6) under high pressure and which flows out of the latter via an outflow opening via a safety valve or an emptying valve, having a blow-off line (12) which connects the outflow opening to a region in the vicinity of the compressed gas container (6), the blow-off line (12) being closed on its side facing away from the outflow opening by a closure element (15) which opens in the event of a gas flow, the closure element (15) having a cover (17) which is in latching engagement with an opening (22), connected to the interior of the blow-off line (12), in a main body (16) of the closure element (15), the main body (16) having latching elements (19) which interact in latching fashion with recesses (20) in the blow-off line (12), characterized in that, the recesses are formed as grooves (20) in the blow-off line (12).Device according to claim 1, wherein the cover (17) is connected to the base body (16) via a film hinge (18).Device according to claim 1 or 2, wherein the base body (16) and the cover (17) are made of plastic, in particular of antistatic plastic.Device according to claim 1, 2 or 3, wherein the cover (17) is planar on the side facing away from the outflow opening.Device according to one of Claims 1 to 4, wherein the latching elements (19) externally engage around the blow-off line (12).Device according to one of claims 1 to 5, wherein the opening (22) points downwards in the direction of gravity when used as intended.Device according to one of claims 1 to 6, wherein the blow-off line (12) ends at its end facing away from the outflow opening at an angle to its axis (A), wherein the base body (16) of the closure element (15) is formed corresponding to this angle.Use of the device according to any one of claims 1 to 7 for discharging hydrogen or compressed natural gas in a storage device (5) in a vehicle (1).

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