DE102011055537B4 - Hydraulic equipment for a preferably fossil fuel-promoting valve - Google Patents

Abstract

Hydraulic control device of the closing mechanism (1) of a fossil fuel-conveying valve, the hydraulic and / or electrical components are at least partially housed in a thermobox or a thermally insulated container, the housed components are at least partially immersed in an oil tank of the controller, the oil filling as a heat storage volume serves.

Description

The present invention relates to a preferably fossil fuel-promoting valve, as well as a hydraulic control device of such a valve.

The extraction of fossil fuels in particular is increasingly taking place under increasingly extreme conditions either below sea level or in the polar cold of North American or Russian ice steppes. Despite such extreme conditions, particularly high demands are placed on the safety of such conveyor systems from an environmental point of view. Thus, there are new, generally valid security conditions, according to which u. a. Leakage losses (corresponding to a typical accident) must be avoided and in emergencies, such as fires or explosive overpressures in the borehole and / or a subsequent pipeline, a so-called "emergency stop" has to be done independently. In all possible cases a promotion of the fossil energy carrier should be stopped or interrupted.

To promote fossil fuels such as natural gas or oil usually different lengths of pipelines are in use, which are connected via so-called fountain fittings to a downhole conveyor pipe. In the conveyor pipe and / or in the valve safety valves (closing mechanisms) are arranged, which can close the delivery pipe in a malfunction or emergency. The closing of such safety valves is currently either manually via a handwheel or electrically preferably remotely controlled. For this purpose, the valves are equipped with electrical actuators, which must be supplied with electrical energy via a power source. However, it has been found that such safety valves often fail under the extreme conditions mentioned above and therefore the current safety requirements can not always be met.

In view of this situation, the basic object of the invention is to provide an emergency and / or emergency fuse for fountains in the industry promoting fittings or pipelines, which offers a higher reliability even under extreme conditions of use. One goal here is to maintain the functionality of the system even in the event of a total power failure including an on-site emergency power supply.

The above-mentioned object is achieved by a control device for the closing mechanism of the fossil fuel-conveying valve or the conveying pipe connected in front of it with the features of patent claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

In principle, hydraulic / pneumatic and / or electrical components can be protected from cold by being at least partly covered in so-called thermoboxes, which are insulated from the outside temperature. Efforts have also been made to heat these thermoboxes on the inside, for which primarily electric heaters were offered. However, these fail in a total power failure.

The invention therefore proposes, at least partially, that the housed components of the control device, d. h., selected components of the control device, which are particularly sensitive to cold to immerse in an oil tank of the control device, such that they are preferably taken up in the hydraulic oil therein. The hydraulic fluid filling of the oil tank is provided here as a heat storage volume. The advantage of this design is that, even with the elimination of a thermal energy source within the thermobox, the immediate ambient temperature of selected components or all components of the controller can be maintained above a minimum temperature for a predetermined period of time to maintain the operability of the controller.

Preferably, it is provided that the thermobox and in particular the oil tank is heated, for example by arranging electrical heating elements. However, other heat energy sources are conceivable, such as the subsidized fossil fuel itself, which is conveyed out of the borehole at a predetermined temperature.

In order to increase the heat storage volume within the thermobox, it may be provided to house a preferably heated water tank (fluid tank) in the thermobox to thereby provide a supplemental heat storage volume. In this case, the water tank may preferably have an expansion compensation air cushioning in order to thermal expansion due to Compensate for temperature fluctuations. Of course, the water is mixed with antifreeze to reach temperatures up to preferably minus 40 ° C in liquid form.

A development of the control device according to the invention provides the arrangement of a shut-off preferably in the form of a temperature-controlled switching valve, which is preferably also immersed in the oil tank in the oil contained therein and which is intended to control the closing of the valve or the delivery pipe on reaching and / or below a minimum oil temperature in the tank of preferably minus 40 ° C to operate. It should be noted at this point that a so-called silicone oil can be used as the hydraulic fluid, which can maintain its properties required for the control device up to the abovementioned minimum oil temperature.

In order to improve the ease of maintenance of the control device, the thermobox may be equipped with a preferably thermally insulated access door, on the inside or immediately behind the access door selected controls or components of the control device are arranged. These are therefore freely accessible from the outside via the heat-insulated access door and can therefore be maintained or replaced in a simple manner.

Furthermore, it is provided according to an advantageous embodiment of the control device that an electrical emergency power source is connected, for example in the form of a battery to the electrically actuated components of the control device (in addition to the main power source) to an electrical power failure (malfunction of the main power source) for at least temporarily bridging for maintaining the electrical power supply of the respective components. In this way, the control device of the main power source, such as an electrical power line or a power generator is independent.

However, it has been found that in certain extreme situations, an emergency power source according to the above design can fail. In such cases, there is a total power failure. Nevertheless, in order to be able to maintain the functionality at least temporarily in such cases, an auxiliary pressure medium source, for example in the form of a pressure accumulator, is provided for the temporary maintenance of an operating pressure for the control device. Furthermore, the control device preferably has a safety block (shutdown block) for actuating the closing mechanism, which is equipped with purely hydraulically controllable safety valves. These safety valves can be provided with a pressure and / or temperature switching function. As soon as these safety valves detect an emergency situation, for example an extreme overpressure in the delivery pipe or an extreme pressure drop in the downstream pipeline or a dramatic increase in temperature, the safety valves are able to actuate the control device so that the closing mechanisms are in the closed position even in the absence of an electrical power supply to be moved.

In one embodiment of the invention, a pressure relief valve is arranged parallel to the shut-off means or switching valve, via which the pressure upstream of the shut-off / switching valve is limited. This pressure limiting valve is preferably designed to minimize leaks in the seat or needle valve design.

The pressure to be limited can be more than 500 bar, for example 700 or 750 bar.

• 1 zeigt eine hydraulische Steuerungseinrichtung des Schließmechanismus einer fossile Brennstoffe fördernden Armatur oder eines in einem Bohrloch befindlichen Förderrohrs gemäß einem ersten bevorzugten Ausführungsbeispiel der vorliegenden Erfindung, wobei die Steuerungseinrichtung mit einem sogenannten Druckübersetzer ausgerüstet ist und
• 2 zeigt eine hydraulische Steuerungseinrichtung des Schließmechanismus einer fossile Brennstoffe fördernden Armatur oder eines in einem Bohrloch befindlichen Förderrohrs gemäß einem zweiten bevorzugten Ausführungsbeispiel der vorliegenden Erfindung mit einem optionalen Druckübersetzer.

The invention will be described in more detail below with reference to preferred embodiments with reference to the accompanying figures.

• 1 shows a hydraulic control device of the closing mechanism of a fossil fuel-conveying valve or a downhole conveyor pipe according to a first preferred embodiment of the present invention, wherein the control device is equipped with a so-called pressure booster and
• 2 shows a hydraulic control device of the closing mechanism of a fossil fuel-conveying valve or a downhole conveyor pipe according to a second preferred embodiment of the present invention with an optional pressure booster.

According to the 1 is on the left side symbolically a closing mechanism, for example in the form of a closing piston 1 represented, which is biased by a spring in the closed position and is hydraulically held in an open position. The locking mechanism is via a pressure line 2 to a pressure intensifier 4 connected, consisting of a piston-cylinder arrangement with a first large-diameter piston surface and a second small-diameter piston surface. According to the difference between the large-diameter and small-diameter piston surface, an incoming low pressure on the large-diameter piston surface is translated into a high pressure on the small-diameter piston surface with which the closing mechanism is acted upon.

The pressure intensifier 4 is a control valve 6 upstream, via a supply line 8th to a hydraulic pressure source 10 connected.

Between the hydraulic pressure source 10 and the control valve 6 of the pressure intensifier 4 is a manually operated check valve 12 interposed. Between the hydraulic pressure source 10 and the manual shut-off valve 12 is a pressure storage unit 14 to the pressure line 8th connected.

Between the accumulator unit 14 and the manual shut-off valve 12 is to the pressure line 8th a branch line 16 connected to a control block 18 supplied with a hydraulic volume. In the branch line 16 is a manually operated switching valve 20 interposed, which in a switching position, a connection between the hydraulic pressure source 10 and the control block 18 allows and in a second switching position the control block 18 connects to a fluid tank of the control device. Down to the switching valve 20 is another accumulator 22 to the branch line 16 connected.

The control block 18 consists mainly of a first safety valve with pressure switching function 24 and a parallel thereto connected second safety valve with temperature switching function 26 whose one control edge in each case with the volume flow from the branch line 16 can be acted upon. The opposite control edge of the two safety valves are common to a pilot control line 28 connected to a control side of the pressure intensifier control valve 6 in turn connected. In addition, in the pilot control line 28 a manually operable check valve 30 interposed.

Finally, to the pilot control line 28 downstream of the manual shut-off valve 30 another manually operated switching valve 32 connected, its input side to the pressure line 8th downstream of the manually operable check valve 12 connected. This manually operated switching valve 32 thus connects in a first switching position, the one control side of the pressure intensifier control valve 6 directly with the pressure line 8th and in a second switching position with the fluid tank of the control device. The manual switching valve 32 thus serves for the manual actuation of the control valve pressure booster for checking the operability of the control device.

As further from the 1 it can be seen, there is the pressure medium source or hydraulic pressure source 10 present from a first hydraulic pressure pump, which is driven by a preferably electric motor. In addition, a further pressure pump is provided, which can be connected to the aforementioned, motor-driven pressure pump. At least one of the pressure pumps is accommodated in the fluid tank of the control device such that it is immersed in the hydraulic fluid therein. In addition, the pressure booster is disposed within the fluid tank and completely surrounded by the hydraulic fluid therein.

Down to the manually operable check valve 30 is another control branch line 34 connected to the pilot control line. This pilot branch 34 opens to a control side of a switching valve 36 (Shutdown), whose input side to the pressure line 2 between the locking mechanism 1 and the pressure intensifier 4 is connected, and whose output side is connected to the fluid tank. The switching valve 36 Here is spring-biased in a first switching position, in which the pressure line 2 between the locking mechanism 1 and the pressure intensifier 4 is connected to the fluid tank. In a second switching position when pressurized via the pilot control branch 34 is obtained is the switching valve 36 in a locked position.

In one embodiment, not shown, in one the switching valve 36 bypass line provided a pressure relief valve (not shown), which is set to a relatively high pressure of, for example, 700 or 750 bar and on the pressure in the pressure line 2 can be limited to this pressure. When this limit pressure is exceeded, the pressure relief valve bypasses the switching valve 36 the pressure line 2 connected to the fluid tank.

In order to minimize pressure medium losses in the direction of the fluid tank, the pressure relief valve can be designed in seat or needle valve design.

In the pilot branch 34 is upstream of the switching valve 36 another shut-off valve interposed, which is spring-biased in an open position and which is switchable via a thermostat switch in a position in which the pressure in the pilot control branch 34 immediately upstream to the control side of the switching valve 36 is relaxed in the fluid tank. Also the shut-off valve 38 is preferably disposed within the fluid tank so that it is completely surrounded by the hydraulic fluid therein.

It should be noted at this point that the hydraulic fluid is predominantly a silicone oil whose hydraulic properties are guaranteed for the functioning of the control device to at least minus 40 ° C. Furthermore, the entire control device described above is in a thermally insulated and preferably electrically heated thermobox, the heater emits directly heating power to the fluid tank of the control device. Finally, in the thermobox one in the 1 not shown heat storage unit arranged in the form of a water tank, which is also heated and thus represents an additional heat storage source. The shut-off valve 38 is here at a temperature of preferably T = -40 ° C so switched that this in the position for connection of the control side of the switching valve 36 is switched with the tank when the temperature of the hydraulic fluid within the tank drops to minus 40 ° C or below.

Finally, a power supply is provided for the operation of the electric motor and all electromagnetic coils on the corresponding switching valves, which consists either of a transmission line and / or a generator. Parallel to this main power source, an emergency power source is preferably provided in the form of batteries, but in the 1 not shown.

The operation of the control device according to the first preferred embodiment of the invention will be described below with reference to 1 described.

In a normal operation of the controller supplies the hydraulic power source 10 via the pressure line 8th as well as the branch line 16 the control block 18 with a fluid volume. Unless in the control block 18 contained safety valves 24 . 26 do not detect a fault, these are switched to flow, so that the fluid volume from the branch line 16 via the control block 18 in the pilot control line 28 is continued, and ultimately the one control side of the pressure intensifier control valve 6 applied. As a result, the pressure intensifier control valve 6 switched to a position in which the pressure line 8th with the input of the pressure intensifier 4 fluidly connected.

By the fluid loading of the pressure booster of the piston contained therein is moved such that a hydraulic pressure in the pressure line 2 between the intensifier and the closing mechanism 1 is built, the closing mechanism 1 forced into its open position.

Once the safety valves 24 . 26 within the control block 18 detect an emergency, for example, at a certain temperature increase or a pressure drop in a pipeline or a pressure increase in the delivery pipe, the relevant equipped with the appropriate switching function safety valve is switched to a second position in which it is the pilot control line 28 connects to the fluid tank. Due to the resulting pressure drop in the pilot control line 28 switches the pressure intensifier control valve 6 in a switching position in which it is the input side of the intensifier 4 connects to the fluid tank, reducing the pressure in the pressure line 2 decreases.

As a result, the switching valve switches 36 in a position in which the pressure line 2 receives a fluid connection with the fluid tank, whereby the pressure in the pressure line 2 quickly broken down into the tank. In this way, the locking mechanism 1 quickly moved to its closed position.

In the event that the electrical power supply fails and thus the main hydraulic pressure source 10 becomes inoperable supplies the accumulator unit 14 temporarily a fluid volume in the pressure line 8th so as to maintain the operability of the controller. Furthermore, the two safety valves 24 . 26 of the control block 18 Only hydraulically operated, so that they retain their functionality in the event of a total power failure.

As already stated above, the shut-off valve 38 preferably housed in the fluid tank within the hydraulic fluid and is inter alia temperature dependent switched.

As long as the temperature of the hydraulic fluid is above a predetermined value, preferably ≥ -40 ° C, the shut-off valve 38 switched to a through position to the pilot control line 28 with the control side of the switching valve 36 to connect, so that this is switched to a closed position. However, as soon as the temperature of the hydraulic fluid within the fluid tank has dropped to a value of -40 ° C, the shut-off valve switches 38 in a position in which it is the one control side of the switching valve 36 connects to the fluid tank, so that it is switched to a passage position in which it is the pressure line 2 between the locking mechanism 1 and the pressure intensifier 4 connects to the fluid tank and thus the pressure in the pressure line 2 is rapidly degraded. This in turn leads to a closing of the locking mechanism 1 ,

The pressure medium source 10 , the print translator 4 as well as the shut-off valve 38 According to the first embodiment of the present invention, they are preferably housed in the fluid tank and are completely immersed in the hydraulic fluid therein. Thus, at least these components of the control device are tempered by the hydraulic fluid and thus kept in function, even if the heater fails temporarily. The tank, or the hydraulic fluid contained therein acts as a heat storage medium, which gives off heat for a predetermined time. The heat storage capacity of the tank is increased by the arrangement of the additional, not shown, water tank, so that the period of time for reaching the shutdown temperature at the shutdown valve 38 is extended. The thermal insulation of the thermobox, in which the circuit device according to the invention is housed, also hinders a rapid cooling of the hydraulic fluid and the water within the water tank. In this way, an electrical power failure, which could lead to a loss of heating power, be bridged at least temporarily.

The 2 shows a second preferred embodiment of the present invention with an optional pressure booster, as described in more detail below.

As a result, the controller of the second preferred embodiment of the invention has a hydraulic pressure source 10 connected via a pressure line 8th and a pressure line 2 with a control side of a locking mechanism 1 fluidly connected. To the pressure line 8th is a pressure storage unit 14 connected to in case of failure of the hydraulic pressure source 10 the hydraulic pressure in the pressure line 8th at least temporarily to maintain. Furthermore, in the pressure line 8th downstream of the accumulator unit 14 a manually operable check valve 12 interposed.

Upstream to the manually operable check valve 12 branches a branch line 16 from the pressure line 8th which, in turn, to the input side of a control block 18 connected. Upstream to the control block 18 is another accumulator unit 22 to the branch line 16 connected.

The control block 18 includes at least one safety valve with pressure switching function 24 and / or a safety valve with temperature control 26 , which are each biased in a passage position and which are switchable by corresponding pressure signals or temperature signals in a switching position, in which a the control block 18 subsequent pilot control line 28 can be connected to a fluid tank.

This pilot control line 28 is with the control side of a check valve 40 connected to the pressure line 8th downstream of the manually operable check valve 12 is interposed and which is spring-biased in the locked position. That is, in the pilot control line 28 built up a pilot pressure, the shut-off valve switches 40 in the pressure line 8th to an open position to build up pressure in the pressure line 2 and thus on the locking mechanism 1 to enable.

From the pilot control line 28 branches a pilot branch 34 starting at the control side of a switching valve 36 is connected, which is spring-biased in an open position, in which the pressure in the pressure line 2 immediately before the locking mechanism 1 is degraded into a fluid tank. D. h., That in the presence of a pilot pressure in the pilot line 28 and thus in the pilot branch 34 the switching valve 36 is switched to a blocking position in which the connection of the locking mechanism 1 is interrupted with the fluid tank.

Finally, in accordance with the first embodiment of the invention, a shut-off valve 38 provided, whose input to the branch line 16 immediately upstream to the control block 18 is connected and whose output side with the control side of another check valve 42 fluidly connected. This further check valve 42 is downstream of the check valve 40 in the pressure line 8th interposed and spring-biased in a locking position. D. h., That in the event that the shut-off valve, which in a Open position is spring-biased, not because of a temperature drop below a cut-off temperature (preferably - 40 ° C) is switched, a pilot pressure at the one control side of the other check valve 42 is applied so that it is switched to its passage position.

• Im Normalbetrieb stellt die Hydraulikdruckquelle 10 ein Fluidvolumen in der Druckleitung 8 bereit, welches über das manuell betätigbare Sperrventil 12, sowie die beiden hintereinander geschalteten Sperrventile 40, 42 und über die Druckleitung 2 an eine Seite des Schließmechanismus 1 angelegt wird. Hierdurch wird der Schließmechanismus 1 in seine Offenposition bewegt. Für den Fall, dass der elektrische Antrieb der Hydraulik-Druckquelle 10 ausfällt, steht eine nicht weiter dargestellte elektrische Not-Energiequelle beispielsweise in Form von Batterien zur Verfügung, welche die Funktion der Hydraulik-Druckquelle 10 zumindest temporär aufrecht erhält. Sollte auch diese Notstromquelle ausfallen, ist die Druckspeicher-Einheit 14 für die temporäre Aufrechterhaltung des Betriebsdrucks innerhalb der Druckleitung 8 und der Druckleitung 2 verantwortlich.

The operation of the control device according to the second preferred embodiment of the invention will be described below:

• In normal operation, the hydraulic pressure source 10 a fluid volume in the pressure line 8th ready, which via the manually operable check valve 12 , as well as the two blocking valves connected in series 40 . 42 and over the pressure line 2 to one side of the locking mechanism 1 is created. This will be the closing mechanism 1 moved to its open position. In the event that the electric drive of the hydraulic pressure source 10 fails, is an unrepresented electric emergency power source, for example in the form of batteries available, which is the function of the hydraulic pressure source 10 at least temporarily maintains. Should this emergency power source also fail, the pressure accumulator unit is 14 for the temporary maintenance of the operating pressure within the pressure line 8th and the pressure line 2 responsible.

In accordance with the first preferred embodiment of the invention, the safety valves are within the control block 18 purely hydraulically operated, so that they are unaffected by a total power failure. These safety valves 24 . 26 record gas pressure changes in the delivery pipe or in the downstream pipeline and / or changes in the temperature in order to provide the downstream pilot control line in the event of a dangerous situation 28 to connect with the fluid tank. Due to the resulting abrupt reduction of the pilot pressure in the pilot line 28 becomes the check valve 40 in the pressure line 8th switched to its blocking position and at the same time the switching valve 36 switched to its open position. This causes a rapid pressure reduction in pressure line 2 and thus on the locking mechanism 1 , whereby this is moved to its closed position.

In the event that the ambient temperature of the control device reaches a cut-off value of preferably t ≦ -40 ° C., the cut-off valve becomes 38 switched to a position in which one on the control side of the further check valve 42 adjacent control pressure is released into the fluid tank. As a result, the other check valve 42 switched to its locked position.

It should be noted that parallel to the aforementioned switching valve 36 for selectively connecting the locking mechanism 1 with the fluid tank another switching valve 44 via the pressure line 2 to the locking mechanism 1 is connected, which is spring-biased in an open position, in which it is the closing mechanism 1 connects to the fluid tank. An opposite control side of the other switching valve 44 is from the control pressure of the further shut-off valve 42 applied.

Also in this embodiment, parallel to the switching valve 44 (Abschaltmittel) a pressure relief valve of the type described above are arranged so that when exceeding a limit pressure in the pressure line 2 also with closed switching valve 36 respectively 44 a pressure medium connection to the fluid tank can be controlled. In the embodiment according to 2 However, it is only necessary to one of the switching valves 36 or 44 to arrange a pressure relief valve in parallel.

In this respect, the other switching valve takes over 44 In addition, the same function as the aforementioned switching valve 36 , that is, in the event that the shut-off valve 38 is switched in fluid tank connection position (t ≤ -40 ° C) and thus the control pressure for the other check valve 42 is degraded, and the other switching valve 44 is switched to a fluid tank connection position, whereby the pressure in pressure line 2 for keeping the locking mechanism open 1 is relaxed quickly.

With respect to the cold protection measures for maintaining the operability of the control device according to the second preferred embodiment, the description of the first preferred embodiment of the invention according to the 1 directed.

The present invention discloses a hydraulic and / or pneumatic control device of the closing mechanism of a fossil fuel-conveying valve whose hydraulic / pneumatic and / or electrical components are housed at least partially in a thermobox. According to the invention, the housed-in components are at least partially immersed in an oil tank of the control device which acts as a heat store and therefore heats up.

LIST OF REFERENCE NUMBERS

closing mechanism 1 pressure line 2 Pressure intensifier 4 control valve 6 pressure line 8th Hydraulic pressure source 10 Manual shut-off valve 12 Pressure accumulator unit 14 branch line 16 control block 18 switching valve 20 Accumulator (unit) 22 Safety valve with pressure switch function 24 Safety valve with temperature switching function 26 pilot line 28 Manual shut-off valve 30 Manual switching valve 32 Pre-branch 34 switching valve 36 shut-off valve 38 check valve 40 Another check valve 42 Another switching valve 44

Claims (15)

Hydraulic control device of the closing mechanism (1) of a fossil fuel-conveying valve, the hydraulic and / or electrical components are at least partially housed in a thermobox or a thermally insulated container, the housed components are at least partially immersed in an oil tank of the controller, the oil filling as a heat storage volume serves. Control device according to Claim 1 , characterized in that the thermobox or the heat-insulated container and the oil tank is electrically heated. Control device according to one of the preceding claims, characterized by an additional, preferably heated water tank, which is housed in the thermobox or the heat-insulated container to provide a supplementary heat storage volume, the water tank having an expansion compensation air cushion. Control device according to one of the preceding claims, characterized by a shut-off means (38) in the form of a temperature-controlled switching valve, which is immersed in the oil tank and actuates the control for closing the valve upon reaching and / or falling below a minimum oil temperature in the oil tank. Control device according to Claim 4 , characterized in that the shut-off means (38) causes a reduction of the pressure in the oil tank, which holds the closing mechanism (1) in its open position. Control device according to Claim 5 characterized by a switching valve (36) biased to an open position for connection of the closing mechanism (1) to the oil tank and to one thereof Control side of the shut-off (38) controlled pilot pressure can be applied, which switches the switching valve (36) in a blocking position. Control device according to one of the preceding claims, characterized in that a silicone oil is used as the oil filling, which retains its required properties up to a tank temperature of -40 ° C. Control device according to one of the preceding claims, characterized by a heat-insulated access door to the thermally insulated thermobox or the heat-insulated container, wherein on the inside of the access door or directly behind the access door selected controls of the control device are arranged. Control device according to one of the preceding claims, characterized by at least one pressure booster (4) which can be connected via control elements to a pressure medium source (10) in order to translate the low pressure generated by the pressure medium source (10) into a high pressure actuated by the closing mechanism. Control device according to Claim 9 , characterized in that the pressure booster (4) and / or the pressure medium source (10) are immersed as hydraulic components of the control device in the oil tank. Control device according to one of the preceding claims, characterized by an electrical emergency power source in the form of at least one battery for temporarily bridging an electrical power failure for the maintenance of an electrical power supply of the hydraulic / pneumatic components. Control device according to one of the preceding claims, characterized by an auxiliary pressure medium source in the form of at least one pressure accumulator for the temporary maintenance of an operating pressure for the control device in the event of failure of the pressure medium source (10). Control device after Claim 12 characterized by a safety block for actuating the closing mechanism (1) equipped with a number of pressure and / or temperature switching safety valves (24, 26) connected at least to the auxiliary pressure medium source for controlling the control device in the event of total power failure even without electrical emergency energy to sustain at least temporarily. Control device after Claim 5 or 6 or one of the claims related to this, wherein a pressure relief valve is arranged parallel to the shut-off means (38) or to the switching valve (36, 44). Control device after Claim 14 , wherein the pressure relief valve is designed in seat or needle valve design.

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