EP1097326A2

EP1097326A2 - Safety device for cutting off gas pipelines

Info

Publication number: EP1097326A2
Application number: EP99932853A
Authority: EP
Inventors: Klaus Schulze
Original assignee: Mertik Maxitrol GmbH and Co KG
Current assignee: Maxitrol GmbH and Co KG
Priority date: 1998-07-13
Filing date: 1999-07-08
Publication date: 2001-05-09
Also published as: WO2000004310A2; PL346128A1; CZ200120A3; TR200100040T2; CA2337410A1; JP2002520563A; HUP0103970A2; BR9912048A; US6550495B1; DE19831283C1; WO2000004310A3; KR20010053510A; HUP0103970A3

Abstract

The invention relates to a thermal security device for cutting off gas pipelines, wherein gas transfer is prevented by said safety device when temperature increases in the section of the gas pipeline placed downstream from said security device, especially when connected gas apparatuses are in a closed position. The aim of the invention is to maintain production costs and dimensions at a level as low as possible. The inventive device comprises a check valve (2) which prevents back flow from the gas pipeline which is placed downstream from said device. The inventive device also comprises a pressure sensitive element (3) which is actuated by the pressure in the pipeline placed downstream from said safety device. Said pressure sensitive element (3) is coupled to a cut-off valve (1) in such a way that when pressure increases in the downstream pipeline said valve (1) prevents gas from flowing into the pipeline. The inventive safety device is used to cut off automatically gas pipelines when temperature increases in an unacceptable way in the section of the pipeline which is placed downstream from said safety device.

Description

description

Safety device for shutting off gas-bearing piping systems

Technical field

The invention relates to a safety device for shutting off gas-carrying line systems in the event of an inadmissible temperature increase according to the preamble of the first claim.

State of the art

Such thermal valve fuses, which are used in pipelines, such as in front of gas fittings, gas devices, gas meters, etc., are available in a variety of designs. They serve to interrupt the gas supply when the temperature rises before the temperature on the gas devices mentioned becomes so high that their external tightness is at risk.

For example, EP 118 152 A1 discloses a valve in which a ball is held in the open position or in the closed position on the one hand by a spring and on the other hand by a part consisting of an alloy with thermal shape memory, the spring being so is formed that an automatic opening is not possible after the closing process.

With this solution, it is disadvantageous that the part located in the interior of the housing made of the alloy with thermal shape memory must be subjected to the higher temperature in order to achieve the desired closing of the valve. This means that the entire valve must be warmed up so that the temperature-sensitive part responds through heat conduction. Furthermore, it is necessary that such a valve is in the immediate vicinity of each component at risk from increased temperature must be arranged to detect the temperature in this area and, if necessary, to shut off the gas line.

EP 343 615 A1 describes a valve which has a cone as a shut-off element. In this solution, the guide rod penetrating the cover of the valve connects the cone to a melting body which is prestressed against the cover by a compression spring. As soon as the melting body softens, the guide rod is pulled out of it so that the cone can suddenly move in the closing direction under the action of the compression spring.

With this solution, too, it is disadvantageous that on the one hand the temperature-sensitive element is located inside the housing and therefore the entire valve must also be heated here, and on the other hand that such a valve is arranged in the immediate vicinity of each component which is at risk from increased temperature got to.

Furthermore, a thermal safety valve is known from utility model DE 9420607. This thermal safety valve has basically the same structure as the solution described above, i.e. there is a fusible link in the housing that holds a shut-off element, in this case a valve plug, in the open position. In addition, however, a heating jacket is placed on the valve housing in the area of the fusible link, which is preferably electrically heatable, so that the safety valve not only triggers automatically when the higher temperature is applied directly to the fusible link, but also that it is a female solution is possible.

This solution has the disadvantage that, in addition to the more complicated structure, it is necessary to provide an additional auxiliary energy source, to lay lines and to provide appropriate actuation options.

EP 637 457 A1 describes a device for automatically closing a shut-off valve. The element that inhibits the closing force has at least at least a pressurized volume-variable hollow body with at least one predetermined breaking device, which consists of a material whose melting temperature is set to a defined limit temperature. When the limit temperature is reached or exceeded, the closing process is triggered by the material of the predetermined breaking device melting and the pressure escaping. The compressive force in the hollow body is reduced and the closing force takes effect. The predetermined breaking device can be designed as a reaction line, which can be installed at any distance from the shut-off valve. A fire that occurs in the area of the reaction line, but at a distance from the shut-off valve, therefore results in the shut-off valve closing.

It is disadvantageous here that the reaction line must extend across the entire area of the system to be protected, which in particular in the case of larger systems results in a disproportionately high outlay.

From DE 296 12 921 U1 a shut-off valve for a gas-carrying line system, with a shut-off element, which is held in the open position by at least one element that inhibits a closing force, is known. The element has at least one pressurized volume changeable

Hollow body, which is connected to a so-called functional line, which consists of a material whose melting temperature is set to a defined limit temperature. When the functional line melts, a pressure drop occurs in the hollow body and the closing force actuates the shut-off element, so that the shut-off valve is closed and the flow through the line system is prevented. A backflow preventer is additionally arranged in the outlet of the line system, which prevents the gas from flowing back out of the downstream line system in the event of a pressure drop in the line system.

With this shut-off valve, there is pressure in the hollow body and in the functional line that is required to hold the shut-off element in the open position. The- However, this pressure is independent of the pressure prevailing in the gas-carrying pipeline system.

It is also known to use so-called gas flow monitors to automatically shut off gas lines. These gas flow monitors serve to interrupt the gas supply when the gas consumption increases above a predetermined value.

With these gas flow monitors, however, it is disadvantageous that if the gas line is damaged, for example by fire, and when the gas device is closed, the gas volume flow flowing out of the leak must be greater than the gas volume flow otherwise required for operating the gas device before the gas flow monitor closes he follows.

Presentation of the invention

The invention is based on the problem of developing a safety device for shutting off gas-carrying line systems of the type mentioned, which prevents the gas flow through the safety device when the temperature increases in the region of the gas-carrying line system downstream of the safety device, in particular when the connected gas devices are closed. In addition, the possibility should be created to avoid an excessive pressure rise in the downstream line system. Furthermore, the manufacturing effort and size should be kept as low as possible. According to the invention, the problem is solved in that the safety device has a check valve which prevents backflow from the gas-conducting line system downstream of the safety device, and in that a pressure-sensitive element acted upon by the pressure prevailing in the downstream line system is also arranged in the safety device. This pressure-sensitive element is coupled to a closing valve in such a way that when the pressure in the downstream line system rises the closing valve prevents gas flow into the downstream line system.

A solution has thus been found with which the previous disadvantages of the prior art, that a thermal element located inside the housing must be subjected to the higher temperature in order to achieve the desired closing of the valve, have been eliminated. Furthermore, it is no longer necessary that such a valve must be arranged in the immediate vicinity of each component at risk from increased temperature in order to detect the temperature in this area and, if necessary, to shut off the gas line. Furthermore, this solution is characterized above all by its simplicity and small size.

Further advantageous embodiments of the invention emerge from the other patent claims. In order to prevent, for example, that the pressure rise occurring in the downstream line system when the temperature rises, the non-return valve or a bypass that bypasses this non-return valve allows a backflow from the downstream line system to be released after the gas flow into the downstream line through the shut-off valve Line system is shut off, whereby a backflow from the downstream line system is also released by the closing valve.

In order to simplify assembly, above all, the movable closing element of the check valve can be a piston or a diaphragm plate which is loaded against the flow direction of the gas by a spring and / or by its own weight. The piston or membrane plate can simultaneously form the pressure-sensitive element.

A design which is particularly advantageous in terms of production technology and which is inexpensive is obtained if the piston moves into a bore due to increasing pressure in the gas-conducting line system downstream of the safety device. one is moved, a return movement of the piston being prevented by means of an engaging detent. The bore is sealed by the piston using an elastic seal.

In order to achieve a stroke movement of the piston even at low pressure due to an initially low friction between the piston and the seat and at the same time to ensure the tightness with increasing pressure, the bore is favorably tapered in the direction of movement of the piston.

The region of the bore, which is assigned to the piston after the locking device comes into engagement, expediently has an extension. Due to the fact that the diameter of this extension is larger than the diameter of the piston with an elastic seal, an opening gap is created between the piston and the extension, via which pressure relief in the downstream line system takes place. After this pressure relief, the piston is again under the action of a spring and / or its own weight as well as the detent outside the extension and seals the bore by means of the elastic seal.

A particularly simple manufacturing technology results if the

Locking device consists of an extension of the bore and the elastic seal. In this case, the diameter of the extension is smaller than the diameter of the piston with an elastic seal. Furthermore, the transition from the extension to the hole has a stop.

Another embodiment of the safety device according to the invention for shutting off gas-carrying line systems results from the fact that the pressure-sensitive element is coupled to a gas flow monitor known per se in such a way that the gas flow monitor is in the closed position due to pressure increase in the downstream line system. This can be achieved, for example, in that the pressure-sensitive element at Pressure increase releases a lock of a preloaded spring and the gas flow switch assumes its closed position under the action of the spring.

This coupling to a gas flow monitor makes it possible for the downstream line system to be closed reliably in the event of an accident, regardless of the operating state of the connected gas device.

The axial movement of the piston is advantageously limited on both sides by a seat, the seat located upstream for the piston forming the check valve with the piston, whereas the seat located downstream for the piston forms the gas flow monitor with the piston.

In order to avoid a sudden movement of the piston from its operating position when switching on the gas device, and thus to prevent the gas flow monitor from responding prematurely, the piston has an extension on at least one end face, which, with a clearance fit, slides in an opening which serves as a guide and which in turn slides is sealed gas-tight at the end. The opening process is damped.

Further advantageous configurations result when the safety device has an externally actuable handle with which the spring can be brought into the pretensioned and locked position, and / or with which the safety device in the closed position can be moved into its starting position.

It is also possible to arrange several safety devices in one gas distributor.

Embodiment

The invention is described in more detail below using several exemplary embodiments. Show it: 1 shows a safety device according to the invention with a ball valve in section, FIG. 2 shows a safety device according to the invention in a second embodiment in section in the operating position, FIG. 3 shows a safety device according to the invention in a second embodiment in section in the position during pressure equalization, FIG. 4 shows an inventive device 5 shows a safety device according to the invention in a third version with a gas flow monitor in section in the operating position,

6 shows a safety device according to the invention in a third embodiment in section in the securing position, FIG. 7 shows a safety device according to the invention in a fourth embodiment with gas flow monitor in section in the operating position, FIG. 8 shows a safety device according to the invention in a fourth embodiment with gas flow monitor in section in the 9 a safety device according to the invention in a fourth embodiment with gas flow monitor in section in the securing position, FIG. 10 an inventive safety device in a fourth embodiment with gas flow monitor in section in division of labor,

11 shows a fourth embodiment of a safety device according to the invention with the gas flow monitor closed, FIG. 12 shows a fourth embodiment of a safety device according to the invention with a handle on average.

The safety device according to the invention, which is explained in more detail below, is described in FIG. 1 on the basis of a ball valve known to the person skilled in the art as a closing valve 1. The safety device has a tubular housing 11, which has a connection at both ends, which in this case is drawn as a thread. It goes without saying that a different connection is also possible. A check valve 2 is arranged centrally in the housing 11 following the internal thread on the inlet side. The The direction of flow prevailing in normal operation in the pipe system, referred to in the following text only as the direction of flow, is represented by an arrow.

The check valve 2 in this case consists of two perforated disks 21/22 arranged one behind the other in the direction of flow, each having a slide bearing 211/221 in the center for an axially movable tappet 23, on which a piston 24 is fastened between the perforated disks 21/22. A pressure spring 25 acts on the end face of the piston 24 facing away from the gas inlet 113 and is supported with its other end on the perforated disk 22. To ensure the gas tightness of the check valve 2 in the closed position, an O-ring is arranged as an elastic seal 242 in a circumferential groove 241 of the piston 24, the valve seat for the check valve being formed by the bore 26 formed conically in the flow direction by the inner wall of the housing 11 2 is realized.

The housing 11 furthermore has a ball which serves as a closing body 12 and is rotatably mounted in seals serving as seat 16 and which is provided in the longitudinal direction of the housing 11 with a through hole 121. An axis 14, which is radially outwardly guided by a tubular attachment 112, which is integrally connected to the housing 11 of the ball valve 1, and is gas-tightly supported by O-rings 13, is connected on the one hand in a form-fitting manner to the ball 12 and on the other hand to a handle 15, by means of which a pivoting movement of the ball valve 1 can be brought into its open or closed position. The construction and mode of operation of the ball valve 1 are known to the person skilled in the art and therefore need not be explained in more detail here.

A pressure-sensitive element 3 is arranged between the ball valve 1 and the check valve 2. The pressure-sensitive element 3 consists of a pot-shaped metal bellows 31 which is attached to the inside wall of the housing 11 in a gas-tight manner and protrudes radially into the interior of the housing 11, on the bottom of which a plunger 32 is fastened, the other end of which is in a wall of the housing 11 located through bore 111 is guided to be longitudinally movable. A pressure piece 33 is supported on the tappet 32 and protrudes outward from the housing 11.

Furthermore, an L-shaped cranked lever is rotatably mounted on the top 112, one leg 341 of which has an opening 342 into which the end of the pressure piece 33 protruding from the housing 11 projects. The other leg 343 is in contact with the handle 15 when the ball valve 3 is open. Furthermore, a torsion spring 35 is axially guided on the attachment 112, which is supported at one end on the housing 11, while the other end rests on the leg 343 in such a way that it loads the handle 15 in the closing direction of the ball valve 1, the pressure piece 33 having a rest for the lever forms.

The mode of operation of the safety device according to the invention and described in this first exemplary embodiment is as follows:

In the operating position, the ball 12 of the ball valve 1 is open. If the gas device located at the end of the downstream gas-carrying line system, which is not shown, is out of operation, the check valve 2 is in its closed position. Now occurs in the area of the downstream gas-carrying

Line system due to an increase in temperature due to fire, for example, there is an increase in pressure in this line system due to the heating. This pressure increase causes a stroke of the metal bellows 31, as a result of which the pressure piece 33 is lifted out of the through bore 111 and thus out of its catch via the tappet 32. Under the action of the tensioned torsion spring 35, due to the leg 341 no longer held, the leg 343 and thus also the handle 15 are pivoted in the closing direction and the ball valve 1 is closed. The safety device is in the safety position.

In order to prevent an excessive pressure rise in the downstream line system, the safety device described in this exemplary embodiment can be direction additionally have a bypass line. In this bypass line, which connects the upstream and the downstream line system bypassing the safety device, a pressure relief valve known to the person skilled in the art and therefore not explained in detail is functionally arranged such that it is always closed in the direction of flow of the gas, whereas pressure compensation by the downstream one in the upstream pipe system is made possible. The setting of this pressure relief valve has to take place in such a way that it only responds after the closing valve 1 has been closed.

A second modified exemplary embodiment of a safety device according to the invention is shown in schematic form in FIGS. 2 to 4, which is characterized in particular by its simple structure. This safety device according to the invention has a housing 11 with a gas inlet 113 and a gas outlet 114, which is shown in a corner shape in this exemplary embodiment. Gas inlet 113 and gas outlet 114 are each provided with a connection option (not shown) for a gas-carrying line system.

In the housing 11 there is a check valve 2, which consists of a piston 24 and a valve seat formed by a bore 26 in the housing 11, which conveniently widens conically in the direction of flow. In the flow direction behind the bore 26 there is the piston 24, which, as in the first exemplary embodiment, has an O-ring as an elastic seal 242 in a circumferential groove 241 to ensure the gas tightness of the check valve 2 in the closed position. The piston 24 is loaded by its own weight against the direction of flow.

In addition, the piston 24 has an end extension 243 on one side, which is guided in an opening 115 in the housing 11. Inside the opening 115 there is a groove 116 in which a radially resilient element 117, for example a wire bracket, is partially supported, but is otherwise in the opening cross section. The extension 243 has a first constriction 244, in the area of which the resilient element 117 is located in the operating position (FIG. 2). The limitation of the constriction 244 facing away from the piston 24 forms a first stop 245 which limits the opening stroke of the piston 24. The limitation of the first constriction 244 facing the piston 24, on the other hand, has a conical transition 246, so that when the resilient element 117 is reached, it widens into its groove 116 until a second constriction 247 located on the shaft 243, the is located between piston 24 and first constriction 244, comes into engagement. In contrast, the boundary of the second constriction 247 facing the first constriction 244 forms a second stop 248 which limits the stroke of the piston 24 in such a way that it can no longer leave the bore 26 in the flow direction. The second constriction 242 and the second stop 248 thus form a detent 27.

A compression spring 25 is guided on the extension 243 and is located between the housing 11 and the piston 24. In the operating position, this compression spring 25 is freely movable in the longitudinal direction and is therefore ineffective (FIG. 2).

The mode of operation of the safety device according to the invention and described in this second exemplary embodiment is as follows:

In this exemplary embodiment, the piston 24, in conjunction with the bore 26, takes on not only the function of the check valve 2, but also the function of the closing valve 1, and also the function of the pressure-sensitive element 3, which leads to the simple construction already mentioned above.

If the gas device located at the end of the downstream gas-conducting line system, which is not shown, is out of operation, the check valve 2 has closed (FIG. 2). The resilient element 117 is located in the first constriction 244 which, with its stop 245, limits the opening stroke when there is the gas appliance is switched on. If a temperature increase occurs in the area of the downstream gas-carrying pipe system, for example due to fire, the pressure in this pipe system increases as a result of the heating. This rise in pressure causes the piston 24 to move counter to the direction of flow and against the force of the compression spring 25 which then comes into effect and which is supported on the housing 11 and on the piston 24. At the same time, the extension 243 is moved so far by the stroke relative to the resilient element 117 that the resilient element 117 slides over the conical transition 246 into the second constriction 247. With a correspondingly high and undesirable pressure rise, the stroke of the piston 24 has the effect that an opening gap is formed between the elastic seal 242 formed by the O-ring and the bore 26, which leads to pressure relief of the downstream line system (FIG. 3). After the pressure has been released, the piston 24 is again moved under the action of the compression spring 25 into the bore 26 which then serves as the seat 16 of the closing valve 1. The check valve 27 prevents the check valve 2 from opening. The safety device is in the safety position.

FIGS. 5 and 6 show, in schematic form, a further third exemplary embodiment of a safety device according to the invention, modified from the second exemplary embodiment, in which no pressure relief takes place.

This safety device according to the invention also has a housing 11 with a gas inlet 113 and a gas outlet 114, which is shown in a corner shape in this exemplary embodiment. Gas inlet 113 and gas outlet 114 are each provided with a connection option (not shown) for a gas-carrying line system.

In this exemplary embodiment there is also a check valve 2 in the housing 11, which consists of a piston 24 and a valve seat formed by a bore 26 in the housing 11, which advantageously expands conically in the direction of flow. In the direction of flow behind the bore 26 is the piston 24, which, as in the first and second exemplary embodiment, has an O-ring as an elastic seal 242 in a circumferential groove 241 to ensure the gas tightness of the check valve 2 in the closed position. The piston 24 is loaded by its own weight against the direction of flow. Upstream, the bore 26 merges into an extension 262, the diameter of which is smaller than the diameter of the piston 24 with the elastic sealing element 242. Furthermore, the transition from the extension 262 to the bore 26 has a stop 248, so that the elastic sealing element 242 and the extension 262 form the detent 27 suitable for low line pressures. For higher line pressures, the detent 27 can be designed such that the piston 24 has an end extension 243 on one side, which is guided in a guide region 18 of an opening 115, as long as the piston is outside the extension 262.

The mode of operation of the safety device according to the invention and described in this third exemplary embodiment, in which, as already mentioned above, for the sake of simplicity, no pressure relief takes place, is as follows:

If the gas device located at the end of the downstream gas-conducting line system, which is not shown, is out of operation, the check valve 2 has closed (FIG. 5). The extension 243 is located in the guide area 18. If a temperature increase in the area of the downstream gas-carrying pipe system due to fire, for example, the pressure in this pipe system rises as a result of the heating. This increase in pressure causes the piston 24 to move counter to the direction of flow and the piston 24 reaches the widening 262. The latch 27 prevents the check valve 2 from opening. The safety device is in the safety position.

In the version suitable for higher line pressures, the extension moves the extension 243 in the opening 115 so far that it guides the guide leaves rich 18 and assumes the safety position due to the tilting of the extension (Fig. 6).

A modified embodiment of a safety device according to the invention is shown in schematic form in FIGS. 7 to 12. In this exemplary embodiment, the safety device is combined with a gas flow monitor 4.

This safety device according to the invention has a housing 11 with a gas inlet 113 and a gas outlet 114, which is shown in a corner shape in this exemplary embodiment. Gas inlet 113 and gas outlet 114 are each provided with a connection option (not shown) for a gas-carrying line system.

In the housing 11 there is a check valve 2, which consists of a piston 24 and a bore 26 formed by a first constriction in the housing 11. In the flow direction behind the bore 26, the piston 24 is arranged, which has an O-ring as an elastic seal 242 in a circumferential groove 241. The piston 24 is loaded by its own weight against the direction of flow.

In the flow direction behind the piston 24, the housing 11 has a second constriction, which is formed as the seat 41 of a gas flow monitor 4 known per se, the closing body of which in this exemplary embodiment is formed by the piston 24. The piston 24 is attached in one piece to a longitudinally movable tappet 23, which is guided on the one hand in a slide bearing 221 located in a perforated disk 22 in the housing 11 in the flow direction behind the seat 41 and on the other hand in an opening 115. The plunger 23 advantageously has a guide collar 231 which forms a clearance fit with the opening 115. At the opening 115 adjoins an outwardly leading bore 118, which is sealed gas-tight by a plug 17. The bore 118 is offset from the opening 115 so that an additional at least one-sided locking edge 119 for a located in the bore 118 and otherwise longitudinally movable pressure piece 33, which is loaded by a compression spring 25, which is supported on the plug 17, in the direction of the plunger 23. On its end facing the plunger 23, the pressure piece 33 has a funnel-shaped receptacle 331 for the plunger.

The mode of operation of the safety device according to the invention and described in this fourth exemplary embodiment with gas flow monitor 4 is as follows:

The piston 24 also takes over in this embodiment in connection with the seat formed by the bore 26 not only the function of the check valve 2, but also the function of the closing valve 1, and also the function of the pressure-sensitive element 3, which leads to the above simple construction mentioned leads. At the same time, the piston 24 serves as a closing body for the gas flow monitor 4, the seat 41 of which is integrated in the housing 11.

If the gas device located at the end of the downstream gas-carrying line system, which is not shown, is out of operation, the check valve 2 has closed (FIG. 7), i.e. the piston 24 is located in the area of the bore 26. In order to prevent the piston 24 from being moved against the seat 41 by an abrupt opening stroke when the gas device is switched on, the plunger 23 has the guide collar 231 already mentioned above, which is connected with the existing clearance to the opening 115 acts as an attenuator.

If a temperature increase occurs in the area of the downstream gas-carrying pipe system, for example due to fire, the pressure in this pipe system increases as a result of the heating. This increase in pressure causes the piston 24 to move counter to the direction of flow. As a result, the plunger 23 is first moved into the funnel-shaped receptacle 331 and then lifts against the force of the compression spring 25 which comes into effect is supported on the pressure piece 33 and on the sealing plug 17, the pressure piece 33 from the locking edge 119, the locking being released.

With a correspondingly high and undesirable pressure rise, the stroke of the piston 24 has the result that an opening gap is created between the O-ring serving as the elastic seal 242 and the bore 26, which leads to a pressure relief of the downstream line system (FIG. 8). After the pressure has been released, the piston 24 is moved under the action of the compression spring 25 against the seat 41 which then serves as the seat 16 of the closing valve 1 (FIG. 9). The safety device is in the safety position.

After removing the sealing plug 17, it is possible to bring the pressure piece 33 back into its initial position and to tension the compression spring 25.

If the gas device located at the end of the downstream gas-carrying line system, not shown, is in operation, the check valve 2 has opened. It is in the working position (Fig. 10). The piston 24 is located in the area between the bore 26 and the valve seat 41. If an increase in the gas volume flow now occurs in the area of the downstream gas-carrying pipe system, the piston 24 is moved against the seat 41, i.e. the gas flow monitor 4 closes and the safety device is in the safety position (FIG. 11).

In FIG. 12, the exemplary embodiment of a safety device according to the invention, which is shown schematically in FIGS. 7 to 11 and has already been described in detail above, additionally has a handle 15 which can be actuated from the outside and is mounted in a gas-tight manner in a bushing not shown in the housing 11. By actuating this handle 15, the piston 24 can be lifted off the seat 41. With the gas-carrying line systems in good condition and the gas device closed, the safety device in the closed position can thus be moved into its starting position. The safety device according to the invention is of course not limited to the exemplary embodiments shown. Rather, changes and modifications are possible without leaving the scope of the invention. For example, connections can vary. Furthermore, the described combined assemblies can be designed as individual components, or the described components can be replaced by equivalent ones. A combination of, for example, the exemplary embodiments described in FIGS. 2 to 6 is also possible. Furthermore, the safety device according to the invention can also be shown schematically for the fourth embodiment, as shown only in FIG. 12, and can have an externally actuated handle 15, as described above. It is also possible to arrange several safety devices according to the invention in a gas distributor.

List of reference numbers

Closing valve 24 pistons

Housing 241 groove

Through hole 242 Elastic seal

Extension 243 extension

Gas inlet 244 First constriction

Gas outlet 245 First stop

Opening 246 transition

Groove 247 Second constriction

Resilient element 248 Second stop

Bore 25 compression spring

Locking edge 26 hole

Lock body 261 extension

Through hole 262 extension

O-ring 27 detent

Axis 3 pressure sensitive element

Handle 31 metal bellows

Seat 32 tappets

Sealing plug 33 pressure piece

Guide area 331 intake

Check valve 341 leg

Perforated disc 342 opening

Plain bearing 343 legs

Perforated disc 35 torsion spring

Slide bearing 4 gas flow monitors

Tappet 41 seat

Leadership association

Claims

claims

1. Safety device for shutting off gas-carrying line systems when an inadmissible temperature increase occurs, characterized in that the safety device prevents a backflow from the

Has safety device downstream of the gas-carrying line system preventing check valve (2), and that a pressure-sensitive element (3) acted upon by the pressure prevailing in the downstream line system is arranged in the safety device and is coupled to a closing valve (1) in such a way that when the pressure in the downstream line rises

Line system through the closing valve (1) prevents gas flow into the downstream line system.

2. Safety device for shutting off gas-carrying line systems according to claim 1, characterized in that to prevent inadmissible overpressure in the downstream line system through the check valve (2) or bypassing this check valve (2) a backflow from the downstream line system is released after the gas flow into the downstream line system is shut off by the closing valve (1) and that a backflow from the downstream line system can also be released by the closing valve (1).

3. Safety device for shutting off gas-carrying pipe systems according to one of the claims 1 or 2, characterized in that the movable closing element of the check valve (2) is a piston (24) or a diaphragm plate which is counteracted by a spring (25) and / or its own weight the direction of flow of the gas is loaded, and that the piston (24) or membrane plate simultaneously forms the pressure-sensitive element (3).

4. Safety device for shutting off gas-carrying line systems according to claim 3, characterized in that the piston (24) by increasing pressure in the downstream line system can be moved into a bore (26), a return movement of the piston (24) being prevented by means of an engaging detent lock (27), and that by means of the piston (24) by means of an elastic seal (242) the bore (26) is sealed.

5. Safety device for shutting off gas-conducting line systems according to claim 4, characterized in that the bore (26) is tapered in the direction of movement of the piston (24).

6. Safety device for shutting off gas-carrying line systems according to one of the claims 4 or 5, characterized in that the area of the bore (26) which is assigned to the piston (24) after the catch lock (27) comes into engagement is an extension ( 261), whose diameter is larger than the diameter of the piston (24) with elastic

Seal (242), and that by means of the piston (24), the pressure relief occurring in the downstream line system via the opening gap under the action of a spring (25) and / or its own weight, and the detent (27) by means of the elastic seal (242 ) the bore (26) is sealed.

7. Safety device for shutting off gas-carrying line systems according to claim 4 or 5, characterized in that the detent (27) consists of an extension (262) of the bore (26) and the elastic seal (242), the diameter of the extension (262) is smaller than the diameter of the piston (24) with elastic seal (242) and the transition from the extension (262) to the bore (26) has a stop (248).

8. Safety device for shutting off gas-carrying line systems according to claim 1, characterized in that the pressure-sensitive element (3) with a gas flow monitor (4) known per se, in such a manner is coupled that the gas flow monitor (4) is in the closed position due to pressure increase in the downstream line system.

9. Safety device for shutting off gas-carrying line systems according to claim 8, characterized in that the pressure sensitive

Element (3) releases a lock of a prestressed spring (25) when the pressure rises and the gas flow monitor (4) assumes its closed position under the action of the spring (25).

10. Safety device for shutting off gas-carrying line systems according to patent claims 8, characterized in that the axial movement of the piston (24) is limited on both sides by a seat (26; 41), the seat (26) located upstream for the piston having the Piston (24) forms the check valve (2), whereas the seat (41) downstream for the piston (24) forms the gas flow monitor (4) with the piston (24).

11. Safety device for shutting off gas-carrying line systems according to claim 10, characterized in that the piston (24) has on at least one end face an extension (243) which slides with clearance in an opening (115) which serves as a guide and which in turn slides is sealed gas-tight at the end.

12. Safety device for shutting off gas-carrying pipe systems according to claim 9, characterized in that the safety device has an externally actuable handle with which the spring (25) can be brought into the prestressed and locked position.

13. Safety device for shutting off gas-carrying line systems according to one or more of Claims 1 to 12, characterized in that the safety device has a handle which can be actuated from the outside and by means of which the safety device which is in the closed position can be moved into its starting position.

4. Safety device for shutting off gas-carrying line systems according to one or more of claims 1 to 11, characterized in that several safety devices are arranged in a gas distributor.