Clamping assembly for a process valve

Description

[0001] The invention relates to advances in the field of process valves.

[0002] DE 10 2014 013 512 A1 discloses a diaphragm valve with a lower housing part having a valve body, an upper housing part attached to the lower housing part, a diaphragm cooperating with the valve body, an axially adjustable spindle connected to the diaphragm and a pressure piece exerting pressure on the diaphragm, wherein the lower housing part has a receiving pot extending towards the upper housing part in which the diaphragm is received, and the upper housing part is attached in or to the receiving pot, wherein a pressure element acting on the edge of the diaphragm and pressing towards the lower housing part is provided in the upper housing part.

[0003] US 5 112 027 A discloses a metal diaphragm valve comprising a valve body and an inverted, bowl-shaped metal diaphragm made of an elastic material, which has in its center a downwardly projecting collar disc integral with the metal diaphragm.

[0004] EP 0 399 625 A1 discloses a diaphragm valve which uses a multiple annular metal diaphragm welded to a valve stem at its inner circumference. The diaphragm is clamped to the valve body at its outer circumference to seal it and is also clamped at its inner circumference at a point outside the weld seam to prevent the weld seam from being subjected to bending stresses during valve actuation.

[0005] The problems of the prior art are solved by a clamping assembly according to claim 1 and by a process valve according to a further claim.

[0006] A first aspect of the description concerns a clamping assembly according to claim 1.

[0007] The proposed solution forms a basis for tool-free, (partially) automated and therefore improved tensioning of the membrane to create a seal to the outside.

[0008] The internal clamping of the diaphragm within the clamping assembly allows the surface design of both the clamping assembly and the process valve to be decoupled from the clamping process. This increased design freedom enables the surfaces to be designed in a way that improves the cleanability of the process valve.

[0009] Furthermore, the proposed solution replaces and improves previous work on tensioning the diaphragm, thereby not only simplifying but also speeding up service procedures for the process valve.

[0010] Additionally, the proposed solution provides degrees of freedom in the design of the interface to the valve body, since the clamping of the diaphragm does not have to occur simultaneously with the arrangement of the clamping assembly on the valve body.

[0011] Furthermore, the proposed solution enables uniform tensioning of the membrane along the outer rib, thereby increasing the lifespan of the membrane.

[0012] In contrast to purely spring-loaded systems, defined settings of the tension conditions are also possible depending on the customer or specific requirements. This allows the tension of the diaphragm to be adjusted to different operating pressures.

[0013] An advantageous example is characterized by the fact that the clamping assembly converts an essentially rotary movement of the drive into a translational movement of the clamping element oriented along an actuating axis by means of the gearbox.

[0014] The gearbox enables better control of the applied tension on the outer rim of the diaphragm, thus avoiding excessive tension for the material and application of the diaphragm and increasing its service life.

[0015] An advantageous example is characterized by the fact that the gearbox is self-locking.

[0016] This ensures that a set tension is maintained on the outer rim of the diaphragm without continuous control of the drive.

[0017] Due to the self-locking effect of the gearbox, the diaphragm remains jammed without a driven actuator, thus ensuring safe operation of the process valve.

[0018] An advantageous example is characterized by the fact that the clamping assembly includes a through-opening that runs along the actuating axis through the clamping assembly. This through-opening allows the clamping assembly to be positioned between a valve actuator and the valve body, with the valve stem passing through the opening.

[0019] According to the invention, the clamping assembly comprises a sensor unit configured to provide at least one signal that characterizes a voltage acting on the outer edge of the membrane.

[0020] The sensor unit provides a signal that characterizes the tension acting on the diaphragm. This allows for the positioning or regulation of the tension using this clamping assembly. This enables automatic tensioning and release of the diaphragm's outer flange, as well as a permanent seal to the outside. Furthermore, diaphragm replacement and installation are simplified and accelerated by the automatic tensioning and release of the diaphragm's outer flange. In particular, the use of this signal significantly improves or enables tool-free and semi- or fully automated diaphragm tensioning. This allows process valves to be cleaned, replaced, or maintained at short intervals without the need for additional tools. This is especially advantageous in the pharmaceutical and food industries.

[0021] An advantageous example is characterized in that the sensor unit comprises a sensor, wherein the sensor is fixed to the housing, and wherein the sensor provides a signal that characterizes a position of the clamping element and thus the tension acting on the outer flange of the membrane.

[0022] This allows, for example, contactless measurement. Furthermore, this displacement measurement is cost-effective and easy to implement in terms of design.

[0023] An advantageous example is characterized by the fact that the clamping assembly includes an evaluation unit which is designed to operate the drive depending on the at least one signal.

[0024] The evaluation unit thus enables automated tightening and loosening of the outer band of the membrane.

[0025] An advantageous example is characterized in that the evaluation unit is designed to control the drive for tensioning or relaxing the outer rim of the membrane, depending on at least one signal and depending on another signal, in particular a tensioning signal or a relaxation signal.

[0026] A second aspect of the description concerns a process valve comprising the clamping assembly according to the previous aspect, wherein the clamping assembly is arranged between a valve actuator and the valve body.

[0027] The drawing shows Figure 1 schematically shows a process valve with an actuator, a valve body, a diaphragm, and a clamping assembly; Figure 2 shows the clamping assembly with a clamping element and diaphragm; Figure 3 shows another example of the clamping assembly with a worm drive; Figure 4 schematically shows the process valve with a switchable coupling arranged between the actuator, the clamping assembly, and the actuator rod; and Figure 5 shows a state transition diagram for operating the process valve according to Figure 4 .

[0028] The Figure 1Figure 100 shows a process valve 100 in a schematic section, comprising a valve actuator 102, a valve body 104, a diaphragm 106, and a clamping assembly 108. The process valve 100 shown is a diaphragm valve. However, the function of the technical measures described here can easily be applied to other valve types, such as poppet valves, in which a shut-off element and a diaphragm separate to achieve a seal.

[0029] The clamping assembly 108 comprises a housing 110, which is rigidly attached to the valve body 104 of the process valve 100 via an interface 109. The interface can be implemented using interlocking threads, a bayonet fitting, or other detachable fastening methods. Furthermore, a drive 112, fixed to the housing 110, a clamping element 114, and a gearbox 116 are arranged within the housing 110 of the clamping assembly 108. The drive 112 is, for example, an electric motor, a pneumatic drive, or a manual drive that can be operated with or without a tool. The gearbox 116, shown schematically, is connected to the drive 112 on the input side and includes a thread 118 on the output side, for example, in the form of a trapezoidal thread. The gearbox 116 can be designed as a wave gear, a cycloidal gear, a planetary gear, or a spur gear.

[0030] The clamping element 114 is coupled to the drive 112 by the gearbox 116. The clamping element 114 exerts an adjustable tension on a lateral outer flange 120, which surrounds an inner functional area of ​​the diaphragm 106, via an annular contact surface 119 facing the diaphragm 106. The gearbox 116 converts a rotary movement of the drive 112 into a translational movement of the clamping element 114 along an actuating axis 122, thereby increasing or decreasing the tension on the lateral outer flange 120 of the diaphragm 106. The gearbox 116 is designed to be self-locking with the clamping element 114 in order to maintain the set tension on the outer flange 120 of the diaphragm 106 without the drive 112 being actuated.

[0031] Furthermore, the clamping assembly 108 includes a through-opening 124 that extends along the actuating axis 122 through the clamping assembly 108 and the clamping element 114. The through-opening 124 allows the clamping assembly 108 to be mounted between the process valve 100 and the valve actuator 102, with an actuating rod 126 extending through the through-opening 124 to drive the diaphragm 106 of the process valve 100. The actuating rod 126 is coupled to the valve actuator 102 on the valve actuator side and connected to the diaphragm 106 on the valve actuator side. This enables the opening and closing of a fluid channel between a valve seat 128 and the diaphragm 106 by means of the valve actuator 102.

[0032] Furthermore, the clamping assembly 108 includes a sensor unit 130. The sensor unit 130 comprises a sensor that generates a signal 132, which characterizes the voltage acting on the outer flange 120 of the diaphragm 106 and is supplied to an evaluation unit 134. Depending on the signal 132, the evaluation unit 134 determines a control signal 136 for operating the drive 112.

[0033] To tension the outer flange 120 of the diaphragm 106, a tensioning signal 138 and, if applicable, a setpoint or threshold value are supplied to the evaluation unit 134. The drive 112 is accordingly controlled by the evaluation unit 134 to tension the outer flange 120 of the diaphragm 106 until the signal 132 reaches the setpoint or threshold value that characterizes a target tension force.

[0034] To release the tension of the outer band 120 of the diaphragm 106, a release signal 140 and, if applicable, a setpoint or threshold value are supplied to the evaluation unit 134. The drive 112 is accordingly activated by the evaluation unit 134 to release the tension of the outer band 120 of the diaphragm 106 until the signal 132 reaches the setpoint or threshold value, which characterizes no or a reduced tension force.

[0035] In one example, the clamping assembly 108 does not include a sensor unit 130. In this case, defined end positions of the clamping element 114 are provided by stops fixed to the housing 110. If the clamping element 114 encounters one of these end stops, the drive 112 is switched off if a motor current is exceeded.

[0036] In an example building on the previous one, sensor unit 130 is present. The signal 136 for controlling the drive 112 is determined depending on the overcurrent monitoring and on the signal 136 in order to increase operational reliability.

[0037] If the drive 112 is an electric motor, the clamping assembly 108 in an example includes an emergency power supply 117 in the form of a battery or accumulator, in order to be able to operate the drive 112 without an external power supply in the event of maintenance.

[0038] In one example, the drive 112 is not located inside, but outside the clamping assembly 108 (shown with dashed lines). For this purpose, the clamping assembly 108 includes a gearbox interface 113 for the gearbox 116. The interface 113 can be located, as shown, in an area of ​​the clamping assembly 108 that points in the direction of the drive 102.

[0039] Additionally or alternatively, a gearbox interface 115 is arranged laterally on the housing 110 and is accessible from the outside. A manual, electric, or pneumatic drive, different from the drive 112, can be connected via the gearbox interface 115, for example, for maintenance purposes.

[0040] The Figure 2 shows a clamping assembly 108 as an embodiment of the in Figure 1 The clamping assembly 108 is shown schematically. The clamping assembly 108 exerts an adjustable tension on the lateral outer collar 120, which surrounds the inner functional area of ​​the diaphragm 106, via the clamping element 114. The clamping assembly 108 comprises the housing 110, the drive 112 (in this case, an electric motor), the gearbox 116, and the clamping element 114.

[0041] The drive 112 is fixed to the housing 110 and located within the housing 110. The drive 112 is coupled to the gearbox 116. The gearbox 116 comprises, on the valve side, a bearing 202 and a ring gear 204, which is rotatably mounted about the actuating axis 122 in both directions of rotation by means of the bearing 202. The gearbox 116 is designed as a type of planetary gear and comprises a planet carrier 206, which is rotatably mounted about the actuating axis, as well as planet gears 208 and a ring gear 210, which is fixed to the housing 110. The drive 112 drives the planet carrier 206 and the planet gears 208 mounted on it, rotating them about the actuating axis 122. The planet gears 208 roll on the stationary ring gear 210, thereby setting the ring gear 204 into rotation.

[0042] For example, the number of teeth of the gears installed in the gearbox 116 could be implemented as follows: The drive 112 comprises 10 teeth; the planet carrier 206 comprises 95 teeth; the planet gears 208 comprise 28 teeth; the stationary ring gear 210 comprises 106 teeth; and the ring gear 204 comprises 104 teeth. A change in the direction of rotation of the drive 112 accordingly changes the direction of rotation of the ring gear 204, thereby decreasing or increasing the tension on the outer flange 120 of the diaphragm 106, as the tensioning element 114 moves translationally accordingly.

[0043] The clamping element 114 presses with its contact surface 119 against the outer flange 120 of the diaphragm 106. The clamping element 114 is non-rotatable about the adjusting axis 122 to the housing 110 by a positive locking of the clamping element 114 with the housing 110 and is coupled to the ring gear 204 by an external thread 212 aligned along the adjusting axis 122, in particular a 30x2mm trapezoidal thread, into which a corresponding internal thread of the ring gear 204 engages.

[0044] The positive locking between the clamping element 114 and the housing 110 is achieved, for example, by a raised contour on the housing 110 running parallel to the adjusting axis and a correspondingly designed groove on the clamping element 114, in order to block the rotation of the clamping element 114 about the adjusting axis 122 and to allow translation in both directions of the adjusting axis 122. The rotational movement of the ring gear 204 is converted into a translational movement by the interlocking threads.

[0045] The movement of the clamping element 114 along the adjusting axis 122 is converted. This translational movement of the clamping element 114 sets the tension on the outer flange 120 of the diaphragm 106. The thread 212 is self-locking, thus maintaining the set tension on the outer flange 120 of the diaphragm 106 without the need for further actuation of the clamping assembly 108.

[0046] The clamping assembly 108 comprises the through-opening 124, which extends along the actuating axis 122 through the clamping assembly 108 and the clamping element 114. The through-opening 124 allows the clamping assembly 108 to be mounted between the valve actuator 102 and the process valve 100, wherein the drive rod 126 for actuating the diaphragm 106 of the process valve 100 extends from the valve actuator 102 through the through-opening 124 and is attached to a receiving device 214 on the diaphragm 106.

[0047] Furthermore, the clamping assembly 108 includes the sensor unit 130, which comprises, for example, a sensor board, is rigidly connected to the housing 110, and is designed for direct or indirect displacement measurement of the clamping element 114. The sensor unit 130 includes, for example, a Hall sensor or a potentiometer. Additional sensors with different measuring principles may be present on the sensor board.

[0048] The sensor unit 130 enables a more precise adjustment of the tension applied to the outer flange 120 of the membrane 106 by the clamping element 114 through the distance measurement.

[0049] Signal 132 from Figure 1 This characterizes the aforementioned tension. Furthermore, the clamping assembly 108 can be controlled by means of the sensor unit 130 to adapt to the current clamping state of the membrane 106.

[0050] For example, the evaluation unit 134 is designed to increase the tension on the outer flange 120 of the membrane 106 by controlling the drive 112 and subsequently moving the clamping element 114, in order to counteract leakage.

[0051] Of course, other sensor concepts are also conceivable, such as attaching strain gauges for force measurement, especially on the clamping element 114 or on the thread 118, in order to obtain the signal 132 from Figure 1 to provide a signal that characterizes the tension on the outer flange 120 of the membrane 106. Furthermore, it is conceivable, alternatively or additionally, to attach piezoelectric elements as sensors to the thread 118 or to the surface of the clamping element 114 facing the lateral outer flange 120, or to the lateral outer flange 120 of the membrane 106, in order to detect the signal 132 from the Figure 1to provide a voltage that characterizes the voltage on the outer flange 120 of the diaphragm 106. This allows the signal 132 to be generated from Figure 1 the evaluation unit 134 from Figure 1 be supplied.

[0052] Figure 3 The clamping assembly 108 is shown. Figure 2 with an alternative embodiment of the gearbox 116. This embodiment comprises the gearbox 116 in the form of a gear drive, which includes one or more gear pairs 302 and at least one worm drive 304a, 304b. Electric motors 306a, 306b, not visible in the drawing, which form the drive 112, transmit their torque to the gearbox 116 via the respective worm drives 304a, 304b. The worm drive 304a is driven rotationally by the electric motor 306a about an axis 308 extending perpendicular to the actuating axis 122. This rotation is thereby transmitted to the first gear pair 302 about an axis 311 oriented parallel to the actuating axis 122.

[0053] In addition, the ring gear 204 of the gear drive is supported by a thin-section bearing 310, which blocks the translational degree of freedom along the adjusting axis 122 and allows the ring gear 204 to rotate in both directions around the adjusting axis 122.

[0054] Figure 4 This shows another version of the process valve 100 in a schematic form. In contrast to the Figure 1 A switchable clutch 400 is located between the drive 102, which is, for example, an electric motor, the clamping assembly 108, and the drive rod 126. The drive 112 shown in the previous figures is omitted in this example, resulting in cost and space savings. Figure 5 This shows a state transition diagram, which will also be referenced below.

[0055] The switchable clutch 400 transmits a torque applied to the clutch 400 either to the drive rod 126 or to the gearbox 116. A drive-side shaft 402 is driven by the valve actuator 102 and, for example, set into a rotational movement. The torque of the shaft 402 is transmitted to the clutch 400. In operating state B, a control signal S_102 for the valve actuator 102 is operated depending on an applied control signal S_126. The control signal S_126 represents the desired position of the drive rod 126 and thus of the movable section of the diaphragm 106.

[0056] In assembly state M, the control signal S_102 is operated depending on the sensor signal 132 and depending on the clamping signal 138 or the unclamping signal 140.

[0057] A change from assembly state M to operating state B is prevented, for example, if the sensor signal 132 indicates that the lateral area of ​​the membrane 106 is not sufficiently tensioned. This can be done, for example, by comparing the sensor signal 132 with a threshold value.

[0058] A change from operating state B to assembly state M is prevented, for example, when the control signal S_102 indicates that the actuator rod 126 is in a position in which the diaphragm 106 presses on the valve seat 128.

[0059] During operating state B and assembly state M, the output of signal S_400 for switching between the two drive outputs is blocked by the evaluation unit 434. Instead, in a first transition state U1 from operating state B to assembly state M, the evaluation unit 434 moves the drive rod 126 into an assembly position, whereby the shaft 402 is force-bearing and torque-bearing connected to the drive rod 126 and is not force-bearing connected to the gearbox 116. The drive rod 126 is held in the respective position without any torque being applied by the coupling 400. After the drive rod 126 reaches the assembly position, the coupling 400 is actuated via signal S_400 such that the shaft 402 is force-bearing connected to the gearbox 116 instead of the drive rod 126.Only then is the system switched to assembly state M, in which the control signal S_102 determines the tension of the lateral area of ​​the membrane 106.

[0060] The transition to the first transition state is initiated, for example, via a separate signal (not shown) to the evaluation unit 434. For instance, a manually operated element on the process valve could be used to generate this signal.

[0061] The evaluation unit 434 transfers the process valve 100 from assembly state M to operating state B by means of a transition state U2. In the second transition state U2, the evaluation unit 434 checks, based on the sensor signal 132, whether the lateral area of ​​the diaphragm 106 is sufficiently tensioned. If this is not the case, a change to operating state B is prevented. If, however, this is the case, the coupling 400 is first operated by means of the signal S_400 such that the torque-carrying connection between the actuator 102 and the clamping assembly 108 is disconnected and the force-carrying connection between the actuator 102 and the actuator rod 126 is established, and then the change to operating state B is carried out.

Claims

1. Tensioning assembly (108) for a process valve (100), comprising: - a housing (110) having an interface (109) for rigid connection to a valve body (104), - a gearing (116) supported on the housing (110), - a tensioning element (114) arranged at an output of the gearing (116), the tensioning element (114) comprising a pressing surface (119) which is designed to clamp a lateral outer collar (120) of a diaphragm (106) of the process valve (100) between the tensioning element (114) and the valve body (104), characterized by a sensor unit (130) designed to provide at least one signal (132) which characterizes a tension acting on the outer collar (122) of the diaphragm (106).

2. Tensioning assembly (108) according to claim 1, wherein a substantially rotational movement of a drive (112) is converted by means of the gearing (116) into a translational movement of the tensioning element (114), which movement is oriented along an adjusting axis (122).

3. Tensioning assembly (108) according to any of the preceding claims, wherein the gearing (116) is designed to be self-locking.

4. Tensioning assembly (108) according to claim 2, wherein the tensioning assembly (108) comprises a through-opening (124) which extends through the tensioning assembly (108) along the adjusting axis (122).

5. Tensioning assembly (108) according to claim 1, wherein the sensor unit (130) comprises a sensor, wherein the sensor is arranged so as to be fixed with respect to the housing (110), and wherein the sensor provides the at least one signal (132) which characterizes a position of the tensioning element (114) and thus the tension acting on the outer collar (122) of the diaphragm (106).

6. Tensioning assembly (108) according to claim 1 or claim 5, comprising an evaluation unit (134) which is designed to operate the drive (112) on the basis of the at least one signal (132).

7. Tensioning assembly (108) according to the preceding claim, wherein the evaluation unit (134) is designed to control the drive (112), on the basis of the at least one signal (132) and on the basis of a tightening signal (138) or a slackening signal (140), to tighten or slacken the outer collar (120) of the diaphragm (106).

8. Tensioning assembly (108) according to any of the preceding claims, wherein a drive (112) is arranged within the housing (110) so as to be fixed to the housing, and wherein the drive (112) for driving the gearing (116) is coupled to the gearing (116).

9. Tensioning assembly (108) according to any of the preceding claims, wherein the tensioning assembly (108) comprises a gearing interface (113, 115) via which a torque can be transmitted into the gearing (116).

10. Process valve (100) comprising the tensioning assembly (108) according to any of the preceding claims.

11. Process valve (100) according to claim 10, wherein the tensioning assembly (108) is arranged between a valve drive (102) and the valve body (104).

12. Process valve (100) according to the preceding claim, wherein a drive rod (126) driven by the valve drive (102) extends through the tensioning assembly (108) and is connected to the diaphragm (106) for the movement thereof.

13. Process valve (100) according to claim 12, wherein a drive rod (126) driven by the valve drive (102) extends through the tensioning assembly (108) and through the diaphragm, and is connected to a shut-off means for the movement thereof.