Double diaphragm drive with safety function

Abstract

The present invention relates to an actuating valve, in particular a controller without auxiliary energy, for adjusting a process fluid flow for a process plant, such as a chemical plant, in particular a petrochemical plant, a power plant, a food-processing plant, for example a brewery, or a district heating plant, comprising an actuator, an actuating drive for actuating the actuator and an actuating rod that transmits an actuating drive force from the actuating drive to the actuator, wherein the actuating drive has an actuating diaphragm, in particular a control diaphragm, and a driver, which is connected in a force-transmitting manner to the actuating diaphragm and the actuating rod for normal operation of the actuating valve, and a safety actuating diaphragm which is connected in a force-transmitting manner to the actuating rod for abnormal operation of the actuating valve in the event of a failure, such as a break, of the actuating diaphragm in order to move the actuator into a safety and / or closed position, wherein the actuating rod and the driver are mounted so as to be axially movable relative to one another such that the safety actuating diaphragm moves the actuating rod telescopically with respect to the driver in the event of a failure of the actuating diaphragm.

Description

[0001] Double diaphragm actuator with safety function

[0002] The present invention relates to a control valve, in particular a regulator without auxiliary energy, for adjusting a process fluid flow for a process plant, such as a chemical plant, in particular a petrochemical plant, a power plant, a food processing plant, for example a brewery, a district heating plant or the like.

[0003] Control valves of this type are used to adjust, regulate, and / or reduce a pressure or flow rate using an actuator in a flow line of a process plant. The actuator is actuated by a control diaphragm actuated by the pressure of the process medium, which works against the action of a setpoint spring.

[0004] In the typical design of a pressure reducing or flow control valve, if the control diaphragm is damaged or ruptured, the setpoint spring or the return spring of a single-acting actuator opens the valve element completely. This releases the maximum flow rate and can cause an unacceptably high pressure to build up in the connected system, which can lead to serious damage. Such a malfunction of a faulty control valve causes an incorrect process pressure or flow rate, which is not always reliably detected in the process plant. To prevent this, there are control valves in which two diaphragms are coupled so tightly that the control element can continue to function if the control diaphragm ruptures. While this design ensures that the control valve continues to function flawlessly, it has the disadvantage that the defective diaphragm in the actuator is not immediately detected and cannot be repaired.

[0005] The regulator according to DE 4209736 Ai has two diaphragms: a control diaphragm and a safety diaphragm. Under normal conditions, the control diaphragm is pressurized, and the safety diaphragm runs synchronously without load. In the event of a fatigue failure of the control diaphragm, the drive medium leaks through the leak to the safety diaphragm. Since both diaphragms act on the same rod and are rigidly connected, the safety diaphragm takes over control from this point on. In addition, the pressure acts on a diaphragm rupture indicator, which indicates the faulty condition of the device and the need for maintenance.

[0006] However, the malfunction can remain unnoticed for extended periods, which is something that should be avoided today, especially due to increased safety requirements. The safety diaphragm must permanently close the valve element. This means that downstream stations in the process plant are no longer properly supplied, and the malfunction is immediately detected by the process plant and its sensors.

[0007] In DE 3235274 Ai, the control rod is separated between the control diaphragm and the safety diaphragm, with the two sections being non-positively connected during control operation. The setpoint spring is located on the outside of the actuator. If this diaphragm fails, the pressure acts on the safety diaphragm. Due to the decoupling and the now equalized pressure on the control diaphragm, the setpoint spring relaxes until the rod rests against the lower stop. The pressurized safety diaphragm can now close the valve element without the load of the setpoint spring. Due to the double diaphragm and the support of the setpoint spring on the outside of the actuator, the overall length is increased. Because the safety diaphragm works against a so-called opening spring when the actuator moves into the closed position, the valve according to DE 3235274 Ai also only assumes the closed position after a time delay.An object of the present invention is to overcome the disadvantages of the prior art, in particular to provide a generic control valve with a reduced overall length and / or shortened reaction time until the safety and / or closed position is assumed in the event of a malfunction.

[0008] The problem is solved by the subject matter of the independent claims.

[0009] According to this standard, a control valve, in particular a self-operated regulator (SOH), is provided for adjusting a process fluid flow in a petrochemical plant, a power plant, a food processing plant, such as a brewery, or a district heating plant. SOHs are also used in potentially explosive atmospheres because the lack of additional auxiliary energy significantly reduces the risk of explosion.

[0010] A self-powered controller requires no external energy supply to operate the controller, in particular no power supply and no pneumatics, such as no external pneumatic continuous pressure supply to implement the preset or varying control algorithm. The supply energy for providing the appropriate actuating force to adjust the control valve comes exclusively from the working fluid flow to be adjusted or the working fluid itself. This distinguishes a self-powered controller for process plants from a self-powered controller in that no additional operating energy (in addition to the energy already present in the working fluid or working fluid flow), such as electricity or pneumatics, needs to be supplied to the controller in order to perform its actuating task, as well as its measuring and / or control function.

[0011] The control of a controller for a process plant can, in particular, comprise only three essential functions: measuring an operating variable, regulating the operating variable, and executing the actuating movement according to a control and / or regulation routine. Since the controller is self-contained and requires no external auxiliary power supply, operating and installation costs are low due to the lack of an additional power supply.

[0012] The control valve according to the invention comprises an actuator, an actuator drive for actuating the actuator, and an actuating rod that transmits an actuating force from the actuator drive to the actuator. The control valve can further comprise a fluid guide housing with at least one fluid inlet and at least one fluid outlet fluidly connected to the inlet. The actuator can be assigned to the fluid flow channel such that the fluid connection between the fluid inlet and fluid outlet can be severed by means of the valve member. In this respect, the actuator can assume both a closed position, in which fluid flow from the fluid inlet to the fluid outlet is prevented, and at least one open position, in which fluid flow from the fluid inlet to the fluid outlet is permitted.The actuator can, for example, be a valve cone and / or cooperate with a valve seat on the fluid guide side to adjust the fluid flow, particularly in the closed position of the control valve. For example, the actuator is actuated in a translational, particularly stroke-like, actuating movement to open different flow cross-sections or to assume the different control valve operating positions.

[0013] The actuator has a control diaphragm, in particular a control diaphragm, and a driver connected to the control diaphragm and control rod in a force-transmitting manner for control operation of the control valve, as well as a safety control diaphragm connected to the control rod in a force-transmitting manner for incorrect operation of the control valve in the event of a failure, such as a rupture, of the control diaphragm, for moving the actuator into a safety and / or closed position. It has been found in the past that the control diaphragm is often the weakest component of the actuator, as this is often the first to fail. For safety reasons, a second diaphragm, referred to as a safety control diaphragm, is therefore installed in the direction of movement of the control rod, in particular at a certain distance.During control operation of the control valve, when the control diaphragm is functional, the two control diaphragms move essentially synchronously with an actuating movement of the control rod in accordance with the actuating movement of the latter to adjust the actuator.

[0014] The driver can generally be constructed in multiple parts and / or connected to the control diaphragm and the control rod in such a way that, during control operation, the driver follows the actuating movement of the control rod and the control diaphragm. For example, the driver can surround the control rod and / or be sleeve-shaped. During control operation, the driver can transfer the actuating force from the control diaphragm to the control rod or connect the control rod and the control diaphragm to each other in a force-transmitting manner, so that, during control operation, the driver moves the control diaphragm and the control rod synchronously with each other.

[0015] According to the invention, the control rod and the driver are mounted and / or displaceable relative to one another in such a way that, in the event of a control diaphragm failure, the safety control diaphragm moves the control rod telescopically with respect to the driver. The inventive arrangement of the control rod and driver in such a way that a telescopic relative movement is possible in the event of malfunction creates a particularly compact control valve with a short overall length in the actuating direction of the control rod. The nesting of the driver and control rod makes it possible, in particular, to dispense with axial installation space. For example, the control diaphragm separates a drive pressure chamber from a safety actuating chamber formed between the control diaphragm and the safety control diaphragm during normal operation.In the event of a rupture of the control diaphragm, the pressure from the actuator pressure chamber transfers to the safety control pressure chamber and causes an actuating force released from the control diaphragm by the safety control diaphragm to act on the control rod. This force causes the control rod, actuated by the safety control diaphragm, to move relative to the driver and the broken control diaphragm. The control diaphragm can, for example, be preloaded, in particular spring-loaded, and thus, upon rupture of the control diaphragm, moves into a passive position, which is directed in particular in the opposite direction to the actuating movement of the safety control diaphragm, into the safety and / or closed position.In the event of a malfunction, the force-transmitting connection between the driver and the actuating rod and thus between the actuating diaphragm and the actuating rod can be separated, so that the actuating rod can be displaced independently of the defective actuating diaphragm and relative to the driver of the safety actuating diaphragm.

[0016] In an exemplary embodiment of the control valve according to the invention, the control valve has a setpoint spring that counteracts the control diaphragm for the control operation of the control valve. This setpoint spring is arranged between the control diaphragm and the actuator in the direction of travel of the control rod. Because the setpoint spring is arranged between the control diaphragm and the actuator, unlike in the prior art, within the available space as viewed in the direction of actuating movement, the installation space of the control valve, particularly axially, can be further reduced. This further reinforces the fundamental idea of ​​nesting individual components to save installation space. The setpoint spring can be a pair of springs.

[0017] In an exemplary development, the setpoint spring surrounds the actuating rod. Preferably, the setpoint spring can surround the actuating rod concentrically, so that a central axis of the setpoint spring preferably coincides with a central axis of the actuating rod. In a pair of springs or multiple setpoint springs, the individual springs can be arranged concentrically around the actuating rod and concentrically to one another. Alternatively or additionally, the setpoint spring is supported on the actuator side and / or the diaphragm side on a sleeve surrounding the actuating rod. Preferably, the sleeve is firmly connected to the actuating rod on the actuator side or the diaphragm side, so that the spring force can be transmitted to the actuating rod via the sleeve.

[0018] In a further exemplary embodiment, the actuating rod is guided within the driver, in particular guided by the driver. In this embodiment, the driver can preferably surround the actuating rod concentrically and / or have a bore in which the actuating rod is guided in the axial direction. The driver can be rotationally shaped and / or completely or only partially surround the actuating rod in the circumferential direction. In an exemplary development, the driver can have a drive sleeve through which the actuating rod passes and which guides the actuating rod. In a further exemplary embodiment, the telescopic relative movement of the actuating rod and driver is limited. The relative movement can be limited on two or one sides in the axial direction in the direction of the valve seat and / or in the direction of the actuator, thus in the direction of the actuating diaphragm and the safety actuating diaphragm.In other words, the adjusting rod can only be displaced a certain distance in the axial direction relative to the driver. The relative movement can be limited, for example, by a stop.

[0019] In a further exemplary embodiment, a coupling bolt is arranged on the actuating rod. In this embodiment, the driver has an elongated groove within which the coupling bolt moves during the telescopic relative movement. In particular, the coupling bolt can be formed in the region of a diaphragm-side end of the actuating rod. During normal operation, the coupling bolt can couple the actuating rod to the driver. The coupling bolt and the groove can support the guidance of the actuating rod, particularly in the event of malfunction, and in particular prevent a rotational movement between the actuating rod and the driver. The groove can be formed on one side of the driver or extend radially through the entire driver, so that a groove is formed on both radially opposite sides of the driver.Accordingly, the coupling pin can protrude radially on one side of the actuating rod or protrude on both sides of the actuating rod radially opposite each other. The coupling pin and groove can also limit the telescopic relative movement in the axial direction if the coupling pin abuts or rests against the ends of the groove in the axial direction, thus preventing further movement of the coupling pin and thus the actuating rod relative to the driver.

[0020] In another exemplary embodiment, the driver has a circumferential groove in which a detent spring washer is engaged to support synchronous movement of the driver and control rod during control operation of the control valve. The detent spring washer can prevent relative movement in the axial direction between the driver and the control rod during normal operation by the coupling bolt resting against the detent spring washer, and only permits a telescopic relative movement when a force exerted on the safety diaphragm exceeds a certain value, in particular due to a rupture of the control diaphragm. In an alternative embodiment, it can also be provided that the coupling bolt is arranged on the driver and the elongated groove and / or the detent spring washer are arranged on the control rod.

[0021] In an exemplary refinement, the coupling pin is assigned to the detent spring washer in such a way that, in the event of a failure of the control diaphragm, the coupling pin releases the detent spring washer and enables the telescopic relative movement between the driver and the control rod. The detent spring washer and the associated groove ensure, in a particularly simple and reliable manner, that relative movement between the driver and the control rod is only possible in the event of a failure of the control diaphragm. The groove can also be manufactured easily and therefore cost-effectively.

[0022] In another exemplary embodiment, the actuator further comprises a setpoint spring for the control operation of the control valve, which is designed such that it does not exert any spring force when the actuator is moved into the safety and / or closed position by means of the safety control diaphragm. In this embodiment, the setpoint spring therefore only exerts a spring force during control operation that counteracts the control diaphragm, but does not generate a force that counteracts the safety control diaphragm in the event of a control diaphragm failure. As a result, the control diaphragm can move the valve element into the safety or closed position particularly quickly, because the safety control diaphragm does not first have to overcome the spring force of the setpoint spring in order to move the actuator in order to move the valve element into the closed position.

[0023] In a further exemplary embodiment, the control valve comprises a safety spring that counteracts the safety diaphragm in the event of a failure of the diaphragm. In particular, the actuating force applied by the safety spring is directed against the direction of action of the safety diaphragm into an open position. The safety spring can, on the one hand, support the coupling between the diaphragm and the safety diaphragm or between the actuating rod and the driver, and, on the other hand, prevents the valve member from striking the valve seat at high speed during closing, which could lead to damage to the valve member and / or the valve seat. The safety spring can, for example, be arranged between the valve member and the safety diaphragm and / or surround the actuating rod.

[0024] In an exemplary embodiment, the actuating force applied by the safety spring is lower than the actuating force applied by the setpoint spring. In particular, the actuating force applied by the safety spring is at least 10, 20, 30, 40, 50, 60, 70, 80, 90, or up to 100 times lower than the actuating force applied by the setpoint spring. In this way, the safety spring can support the coupling between the follower and the actuating rod during control operation without unnecessarily slowing the closing of the valve element by the safety actuating diaphragm in the event of the actuating diaphragm failure.

[0025] In another exemplary embodiment, a pneumatic effective area during control operation is larger than a pneumatic effective area when moving the actuator into the safety and / or closed position. In other words, the pneumatic effective area of ​​the control diaphragm can be larger than the pneumatic effective area of ​​the safety control diaphragm. In particular, the pneumatic effective area of ​​the safety control diaphragm can be only large enough to move the valve element against the safety actuating spring or only large enough to move the valve element without an opposing spring force. In this way, the dimensions of the control valve can be further reduced.

[0026] Preferred embodiments are given in the subclaims.

[0027] In the following, further properties, features and advantages of the invention will become clear by describing preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which:

[0028] Figure 1 shows an exemplary embodiment of a control valve according to the invention in control operation in an open position; Figure 2 shows the control valve from Figure 1 in control operation in an intermediate position;

[0029] Figure 3 shows a detailed view of the diaphragm-side area of ​​the control valve from

[0030] Figures i and 2 in normal operation;

[0031] Figure 4 is a detailed view of the diaphragm-side area of ​​the control valve from Figures 1 to 3 in faulty operation following a rupture of the control diaphragm; and

[0032] Figure 5 is a detailed view of the valve member side area of ​​a further exemplary embodiment of a control valve according to the invention.

[0033] In the following description of exemplary embodiments, a control valve according to the invention is generally designated by reference numeral 1. Figure 1 shows an exemplary embodiment of a control valve 1 according to the invention, which comprises an actuator 3, an actuator drive 5 for actuating the actuator 3, and an actuating rod 7 transmitting an actuating force from the actuator drive 5 to the actuator 3.

[0034] The control valve 1 also comprises a fluid guide housing 9, which, in the embodiment shown in Figure 1, defines a fluid inlet 11 and a fluid outlet 13 that are fluidly connected to one another. A valve seat 15 that interacts with the actuator 3 is arranged within the housing 9. Figure 1 shows the control valve 1 in an open position, in which the actuator 3 is spaced a distance a from the valve seat 15 in the actuating direction S, so that the fluid inlet 11 and the fluid outlet 13 are fluidly connected to one another and fluid flow is permitted between the fluid inlet 11 and the fluid outlet 13. The actuating direction S corresponds to the displacement direction of the actuator 3.Starting from the open position, the actuator 5 moves the actuating rod 7 and thus the actuating element 3 in the actuating direction S towards the valve seat 15 during control operation until the valve element 3 rests against the valve seat 15 and the control valve 1 has reached a closed position in which the fluid flow between the fluid inlet 11 and the fluid outlet 13 is prevented. The actuator 5 comprises an actuating diaphragm 17 with which the control valve 1 can be actuated during control operation. In the embodiment shown in Figure 1, the actuating diaphragm 17 is rotationally shaped and is fastened to an actuator housing 19 at its outer edge in the radial direction. The actuator housing 19 is constructed in several parts and has an actuator-side housing part 21, a middle housing part 23 and an actuator-side housing part 25. In the embodiment shown in Figure 1, the control diaphragm 17 is clamped between the actuator-side housing part 21 and the middle housing part 23.

[0035] The actuator-side housing part 21 simultaneously delimits a drive pressure chamber 27, into which working fluid can be fed through a fluid line 29 connected to the fluid inlet 11. This allows a fluid pressure to build up in the drive pressure chamber 27, which acts on the control diaphragm 17. The control diaphragm 17 rests against a control diaphragm plate 31. The control diaphragm plate 31 is fastened to a driver, which is generally designated by the reference numeral 33. During control operation of the control valve 1, the driver 33 is connected to the control rod 7 and the control diaphragm 17 in a force-transmitting manner and thus transmits the force generated by the control diaphragm 17 to the control rod 7 in order to displace it. Figure 1 shows that there is no direct contact between the control rod 7 and the control diaphragm plate 31 or the control diaphragm 17.The force-transmitting connection between the control diaphragm 17 and the control rod 7 is thus realized exclusively by the driver 33.

[0036] When working fluid is introduced into the drive pressure chamber 27 through the fluid line 29 during control operation, the control diaphragm plate 31 is moved in the actuating direction S by the fluid pressure acting on the control diaphragm 17. As a result, the driver 33 and the actuating rod 7, which is non-positively connected to the driver 33 during control operation, are moved in the actuating direction S synchronously with the control diaphragm 17 or with the control diaphragm plate 31 in order to bring the control valve 1 into the closed position.

[0037] The actuator 5 also has a safety diaphragm 35, which is arranged in the actuating direction S between the actuating diaphragm 17 and the actuator 3. The safety diaphragm 35 rests against a safety diaphragm plate 37. In the embodiment in Figure 1, the safety diaphragm 35 and the safety diaphragm plate 37 are designed in the same way as the actuating diaphragm 17 and the actuating diaphragm plate 31. In other embodiments, however, it can also be provided that the safety diaphragm is smaller than the actuating diaphragm and / or that the safety diaphragm plate is smaller than the actuating diaphragm plate. The safety diaphragm 35, like the actuating diaphragm 17, is fastened to the actuator housing 19 and clamped between the middle housing part 23 and the actuator-side housing part 25. In the embodiment in Figure 1, the three parts of the actuator housing 19 are fastened to one another with several screws 39.

[0038] The safety control diaphragm 35 is connected to the control rod 7 in a force-transmitting manner and serves to move the actuator 3 into a safety and / or closed position in the event of a malfunction of the control valve 1 due to a failure of the control diaphragm 17, which will be explained in detail later.

[0039] During control operation of the control valve 1, a setpoint spring 41 counteracts the control diaphragm 17. In the embodiment in Figure 1, the setpoint spring 41 is formed by an inner compression spring 43 and an outer compression spring 45, which concentrically surround the control rod 7. The outer spring 45 has a greater spring stiffness than the inner spring 43. In the control valve 1 according to the invention, the setpoint spring 41 is arranged in the actuating direction S between the control diaphragm 17 and the actuator 3. On the actuator side, the setpoint spring 41 is supported via a spring plate 47 on a sleeve 49 surrounding the control rod 7. On the actuator side, the sleeve 49 is firmly connected to the fluid guide housing 9 via several screws 51. In the embodiment in Figure 1, the spring plate 47 is screwed onto the sleeve 49. On the actuator side, the setpoint spring 41 rests against a sleeve 53 which can be moved relative to the actuating rod 7 in the actuating direction S.The sleeve 53 rests on the actuator side against the driver 33, so that the driver 33 and thus the control rod 7 are moved against the spring force of the setpoint spring 41 during control operation to close the control valve 1. Figure 2 shows the control valve 1 from Figure 1 in a further open position, in which the actuator 3 is closer to the valve seat 15 in the actuating direction S compared to the position in Figure 1, so that the distance a between the actuator 3 and the valve seat 15 is smaller than in the position in Figure 1. Thus, the fluid flow between the fluid inlet 11 and the fluid outlet 13 is smaller than in the position in Figure 1. The control operation of the control valve 1 is explained below using a comparison of Figures 1 and 2.

[0040] As already described, the control diaphragm 17 rests against the control diaphragm plate 31. The control diaphragm plate 31 comprises a plate base 32, which extends perpendicular to the actuating direction S, and a plate rim 34, which extends in the actuating direction S. The control diaphragm plate 31 is thus overall bowl-shaped. A circumferential gap 55 is formed between the plate rim 34 and the actuator housing 19. The control diaphragm 17 rests against the plate base 32, the plate rim 34, and the actuator housing 19. The control diaphragm plate 31 is firmly connected to the driver 33 in the center. In this embodiment, the driver 33 is constructed in several parts and comprises a rotationally shaped drive sleeve 57, which is firmly connected to the control diaphragm plate 31. The driver 33 also comprises a rotationally shaped spring sleeve 59, which rests against the drive sleeve 57 on the actuator side and rests against the sleeve 53 on the actuator side.The drive sleeve 57 and the spring sleeve 59 surround the actuating rod 7. A circumferential groove 60 is provided on the outside of the drive sleeve 57, into which a detent spring washer 61 is engaged during control operation. The actuating rod 7 has a coupling pin 63 on the actuator side or diaphragm side, which rests against the detent spring washer 61 during control operation, so that the driver 33 and the actuating rod 7 are connected to each other in a force-transmitting manner during control operation. Thus, the driver 33 and the actuating rod 7 move synchronously during control operation.

[0041] The safety control diaphragm plate 37 is firmly connected to the coupling bolt 63 and thus firmly to the control rod 7 via a rotationally shaped connecting sleeve 65 which concentrically surrounds the drive sleeve 57 of the driver 33, and also moves synchronously with the driver 33 or control diaphragm plate 31 during control operation. In the embodiment in Figures 1 and 2, the control rod 7, the driver 33 connected to the control diaphragm 17 and the connecting sleeve 65 connected to the safety control diaphragm 35 are all nested one inside the other, so that the axial length of the control valve 1 in the actuating direction S can be shortened even further.

[0042] Comparing Figures 1 and 2, it can be seen that during an actuating movement, when the actuating diaphragm plate 31 is moved in the actuating direction S by the fluid pressure acting on the actuating diaphragm 17, the driver 33, the safety actuating diaphragm plate 37, the actuating rod 7, the sleeve 53, and the valve member 3 as a whole are displaced in the actuating direction S, so that the distance a between the actuating member 3 and the valve seat 15 decreases. At the same time, the distance c between the driver 33 and the actuator-side housing part 21 increases, and a distance b is created between the spring sleeve 59 and the actuator housing 19.

[0043] Figures 3 and 4 show how, in the event of a malfunction due to a rupture of the control diaphragm 17, the control valve 1 can be brought into a safety or closed position using the safety control diaphragm 35. Figure 3 shows the actuator-side area of ​​a control valve 1 according to the invention before the diaphragm rupture during control operation, and Figure 4 shows the control valve 1 after the diaphragm rupture during a malfunction.

[0044] According to the invention, the actuating rod 7 and the driver 33 are mounted so as to be axially movable relative to one another that, in the event of a failure of the actuating diaphragm 17, the safety actuating diaphragm 35 moves the actuating rod 7 telescopically with respect to the driver 33. A comparison of Figures 3 and 4 shows that the distance c between the drive sleeve 57 and the actuator housing 19 is the same in Figures 3 and 4. In the event of a malfunction, the driver 33 therefore does not move. In other words, the driver 33 follows the movement of the actuating diaphragm 17 or the actuating diaphragm plate 31. If the actuating diaphragm 17 is displaced during normal operation, the driver 33 moves synchronously with the actuating diaphragm 17. If, in the event of a malfunction, the actuating diaphragm 17 can no longer generate force and therefore does not move, the driver 33 does not move either.In the event of a malfunction, the fluid conducted through the fluid line 29 into the drive pressure chamber 27 can spread into a safety pressure chamber 67 in the actuating direction S between the actuating diaphragm 17 and the safety actuating diaphragm 35, thus generating a compressive force on the safety actuating diaphragm 35. This generates a force in the actuating direction S on the connecting sleeve 65, which presses the connected coupling bolt 63 against the detent spring ring 61, so that the latter is released from the circumferential groove 60 and enables a telescopic movement of the connecting sleeve 65 and the actuating rod 7 relative to the driver 33. This creates a distance d between the actuating diaphragm plate 31, which does not move, and the diaphragm-side end of the connecting sleeve 65. During the telescopic movement, the actuating rod 7 is guided by the drive sleeve 57, which has a central bore 69 in which the actuating rod 7 is received or guided.The drive sleeve 57 has an elongated groove 71 on each of two radially opposite sides, in which the coupling pin 63 is guided and can be displaced in the actuating direction S until the coupling pin 63 abuts an actuator-side end 73 of the grooves 71. The elongated grooves 71 thus limit the telescopic relative movement between the actuating rod 7 and the driver 33.

[0045] Since the sleeve 53, on which the setpoint spring 41 is supported, rests on the driver 33 and is freely movable relative to the actuating rod 7, the setpoint spring 41 does not exert any spring force on the actuating rod 7 in the event of a fault, so that the safety actuating diaphragm 35 can move the actuating element 3 more quickly into the safety or closed position without having to overcome the spring force of the setpoint spring 41.

[0046] Figure 5 shows the actuator-side region of a further exemplary embodiment of a control valve 1 according to the invention in a closed position, in which the actuator 3 rests against the valve seat 15. This differs from the previous embodiments in that the control valve 1 has a safety actuating spring 75, which counteracts the safety actuating diaphragm 35 in the event of a fault and exerts an actuating force counter to the direction of action of the safety actuating diaphragm 35 in an open position. The safety actuating spring 75 can support the coupling between driver 33 and actuating rod 7 in control operation and, in the event of a fault, prevent the actuator 3 from striking the valve seat 15 hard. However, the actuating force applied by the safety actuating spring 75 is significantly lower than the actuating force applied by the setpoint spring 41, so that the safety or closed position can still be reached quickly in the event of a failure.The embodiment in Figure 5 also differs from the other embodiments in that a pressure relief bore 77 is provided in the actuator 3, which, in the closed position, prevents the pressure in the fluid outlet 13 from increasing too much.

[0047] The features disclosed in the above description, the figures and the claims may be important both individually and in any combination for the realization of the invention in the various embodiments.

[0048] List of reference symbols

[0049] 1 control valve

[0050] 3 Actuator

[0051] 5 Actuator

[0052] 7 Adjusting rod

[0053] 9 Fluid guide housing

[0054] 11 Fluid inlet

[0055] 13 Fluid outlet

[0056] 15 Valve seat

[0057] 17 Control diaphragm

[0058] 19 Actuator housing

[0059] 21 Actuator-side housing part

[0060] 23 middle housing part

[0061] 25 Actuator-side housing part

[0062] 27 Drive pressure chamber

[0063] 29 Fluid line

[0064] 31 Control diaphragm plate

[0065] 32 plate base

[0066] 33 drivers

[0067] 34 Outside the Box

[0068] 35 Safety diaphragm

[0069] 37 Safety diaphragm plate

[0070] 39 Screw

[0071] 41 Setpoint spring

[0072] 43 inner spring

[0073] 45 outer spring

[0074] 47 spring plates

[0075] 49, 53 sleeve

[0076] 51 screw

[0077] 55 circumferential gap

[0078] 57 Drive sleeve

[0079] 59 spring sleeve

[0080] 17

[0081] 64 / 844-336 60 circumferential groove

[0082] 61 locking spring ring

[0083] 63 coupling bolts

[0084] 65 connecting sleeve

[0085] 67 Security pressure room

[0086] 69 central hole

[0087] 71 elongated groove

[0088] 73 actuator-side groove end

[0089] 75 Safety spring

[0090] 77 Pressure relief hole

[0091] S Setting direction a, b, c, d Distance

Claims

CLAIMS 1. Control valve (1), in particular a regulator without auxiliary energy, for adjusting a process fluid flow for a process plant, such as a chemical plant, in particular a petrochemical plant, a power plant, a food processing plant, for example a brewery, or a district heating plant, comprising - an actuator (3), - an actuator (5) for actuating the actuator (3) and - an actuating rod (7) transmitting an actuating force from the actuator (5) to the actuating element (3), wherein the actuator (5) has an actuating diaphragm (17), in particular a control diaphragm, and a driver (33) connected to the actuating diaphragm (17) and the actuating rod (7) in a force-transmitting manner for regulating the control valve (1), as well as a safety actuating diaphragm (35) connected to the actuating rod (7) in a force-transmitting manner for incorrect operation of the actuating valve (1) in the event of a failure, such as a rupture, of the actuating diaphragm (17) for displacing the actuating element (3) into a safety and / or closed position, characterized in that the actuating rod (7) and the driver (33) are mounted so as to be axially movable relative to one another in such a way that the safety actuating diaphragm (35) moves the actuating rod (7) telescopically with respect to the driver (33) in the event of a failure of the actuating diaphragm (17).

2. Control valve (1) according to claim 1, further characterized by a setpoint spring (41) counteracting the control diaphragm (17) for the control operation of the control valve (1), which is arranged in the direction of travel of the control rod (7) between the control diaphragm (17) and the actuator (3).

3. Control valve (1) according to claim 2, characterized in that the setpoint spring (41) surrounds the control rod (7) and / or is supported on the actuator side and / or the diaphragm side on a sleeve (49, 53) surrounding the control rod (7).

4. Control valve (1) according to one of the preceding claims, characterized in that the control rod (7) is arranged within the driver (33), in particular by the driver (33), preferably by a drive sleeve (57) of the driver (33) through which the control rod (7) passes. Control valve (1) according to one of the preceding claims, characterized in that the telescopic relative movement of Control rod (7) and driver (33). Control valve (1) according to one of the preceding claims, characterized in that a coupling bolt (63) is arranged on the control rod (7), particularly in the region of a diaphragm-side end, which couples the control rod (7) to the driver (33), particularly during control operation, and the driver (33) has an elongated groove (71) within which the coupling bolt (63) moves during the telescopic relative movement. Control valve (1) according to one of the preceding claims, characterized in that the driver (33) has a circumferential groove (60) in which a detent spring ring (61) is engaged in order to support a synchronous movement of the driver (33) and control rod (7) during control operation of the control valve (1).Control valve (1) according to claim 7, characterized in that the coupling bolt (63) is assigned to the detent spring ring (61) in such a way that, in the event of a failure of the control diaphragm (17), the coupling bolt (63) releases the detent spring ring (61) and enables the telescopic relative movement between the driver (33) and the control rod (7). Control valve (1) according to one of the preceding claims, characterized in that the actuator (5) further comprises a setpoint spring (41) for the control operation of the control valve (1), which is designed such that it does not exert any spring force when the actuator (3) is moved into the safety and / or closed position by means of the safety control diaphragm (35). Control valve (1) according to one of the preceding claims, further characterized by a safety control spring (75) counteracting the safety control diaphragm (35) in the event of a failure of the control diaphragm (17), wherein in particular the force exerted by the safety control spring (75) The actuating force is directed counter to the direction of action of the safety actuating diaphragm (35) into an open position. The control valve (1) according to claim 10, characterized in that the actuating force applied by the safety actuating spring (75) is lower, in particular at least by a factor of 10, 20, 30, 40, 50, 60, 70, 80, 90, or up to 100, than the actuating force applied by the setpoint spring (41). The control valve (1) according to any one of the preceding claims, characterized in that the pneumatic effective area during control operation is larger than the pneumatic effective area when the actuator (3) is displaced into the safety and / or closed position.

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