VALVE DRIVE

Description

[0001] The invention relates to valve actuators for valves for limiting the flow of a process fluid.

[0002] US2017328489, WO9744645, US9341270, EP2998625, US2108234 and EP3287679 relate to different types of valves. US 2015 / 0354718 A1 discloses a diaphragm valve with an actuator spindle positively connected to a diaphragm.

[0003] The problems of the prior art are solved by a valve actuator according to claim 1. Advantageous further developments are found in the dependent claims and further in the following description of examples. According to a first aspect of this description, a valve actuator for a valve is provided.The valve comprises: a first section of an actuator rod displaceable along a feed axis and arrangable in a housing, with a first coupling contour; an electromechanical drive unit with an axially movable second section of the actuator rod, wherein the second section of the actuator rod comprises a second coupling contour, wherein the first and second coupling contours interlock positively along the feed axis in an operating state of the valve actuator in which the housing and the drive unit are fixed relative to each other; and wherein the second coupling contour is removable from the first coupling contour and can be coupled to the first coupling contour in an assembly state of the valve actuator in which the housing and the drive unit are not fixed relative to each other.

[0004] The removable and connectable design of the second coupling contour offers the advantage of reduced wear during the assembly and disassembly of the valve actuator compared to the first. This low-wear coupling of the two actuator rod sections allows for high switching cycles. Furthermore, it ensures that, during operation, the force generated by the electric motor drive unit is precisely transferred to the actuator rod and directed towards the shut-off element in the valve body. In addition, the simple design facilitates easier replacement and thus reduces setup times, thereby minimizing downtime for the respective system.

[0005] Furthermore, the invention is characterized in that the second coupling contour, in the assembled state of the valve actuator, is displaceable in an imaginary perpendicular plane of the feed axis relative to the first coupling contour, such that the second coupling contour can be separated from the first coupling contour by a lateral movement of the drive unit. Advantageously, the displaceability in the imaginary perpendicular plane ensures that contact surfaces lie in a corresponding further perpendicular plane of the feed axis. This reduces asymmetrical stresses during force transmission across the two coupling contours and ensures uniform force transmission. A virtually backlash-free connection is thus made possible.

[0006] An advantageous example is characterized by the fact that the first and second coupling contours are connected to each other along the feed axis with virtually no backlash. This near-backlash connection between the first and second sections of the drive rod allows the diaphragm to be moved precisely and quickly by the drive unit. This advantageously reduces the cycle time while simultaneously achieving precise movement of the diaphragm.

[0007] An advantageous example is characterized by the fact that the valve actuator comprises: a first housing connection area of ​​the housing in which the section of the actuator rod is axially displaceably fixed along the feed axis; and a second housing connection area of ​​the actuator unit, wherein the first housing connection area corresponds to the second housing connection area such that, in the operating position, the first and second sections of the actuator rod lie on the common feed axis. Advantageously, the first and second housing connection areas ensure the coaxial alignment of the actuator rod sections on the common feed axis.

[0008] An advantageous example is characterized by the fact that a non-self-locking gearbox is arranged between an electric motor of the drive unit and the second coupling contour of the second section. Advantageously, the drive unit can be easily connected to the second section of the drive rod, since the first section of the drive rod can be manually pulled out far enough, due to the non-self-locking gearbox, to couple with the first section.

[0009] An advantageous example is characterized in that the preload assembly comprises a counter-bearing section and a clamping section for clamping the diaphragm, wherein the clamping section is supported on the counter-bearing section by means of the pressurized spring element, wherein the clamping section comprises a first stop area in a section projecting through a through-opening of the counter-bearing section, and wherein, in the preloaded state of the preload assembly, a second stop area of ​​the counter-bearing section, in conjunction with the first stop area of ​​the clamping section, limits movement of the clamping section away from the counter-bearing section.

[0010] Advantageously, a modular design of the prestressing assembly is provided, which can be easily replaced in the event of a defect or during maintenance work. In particular, the individual parts of the prestressing assembly are arranged securely relative to each other via the two stop areas.

[0011] A second aspect of this description, not according to the invention, relates to a valve actuator for a valve which limits a flow of a process fluid, wherein the valve actuator comprises: a drive rod movable along a feed axis, which is designed to move a diaphragm, a pneumatic piston rigidly connected to the drive rod, a housing which provides a movement space for the pneumatic piston, wherein the pneumatic piston divides the movement space into a proximal and a distal chamber, wherein a control air channel of the housing connects one of the two chambers and a control air connection to each other in an air-conducting manner, and wherein the control air connection is connected to a surface distally bounding the housing.

[0012] This arrangement of the control air connection advantageously frees up lateral installation space. Consequently, the valve density of a system can be increased. Furthermore, the proposed valve actuator utilizes the available vertical space to route and connect control air lines to the actuator. Additionally, the actuator can, for example, be screwed onto the associated valve body, with the position of the control air connection changing only slightly when the actuator rotates, compared to a lateral arrangement.

[0013] An advantageous example is characterized by the fact that the control air connection is arranged at a distance from the feed axis. This decentralized arrangement leaves an area around the feed axis free, which can be used for other devices such as a stroke limiter.

[0014] The same reference symbols are used for functionally equivalent features, even in different examples. The diagram shows: Figure 1 a valve actuator in schematic form; Figure 2 a schematic perspective view of the valve drive Figure 1 ; and Figure 3 and 4 Each valve actuator is shown in a schematic section.

[0015] Figure 1Figure 1 shows a schematic representation of a valve actuator 2, which is screwed onto a valve body 4. A shut-off device (not shown) is arranged on an actuator rod 6 and limits the flow of a process fluid flowing between ports 8 and 10 of the valve body 4. A preload assembly 12 comprises a clamping section 14, which passes through an opening of a counter-bearing section 16 and provides a first stop area for the counter-bearing section 16. In the installed state of the preload assembly 12, the counter-bearing section 16 is supported by a diameter recess 18 of the housing 20. A spring element 22, for example in the form of a disc spring assembly, is supported by the counter-bearing section 16 and presses the clamping section 14 with a proximal clamping area (not shown) onto a clamping section of the shut-off device (not shown), in particular a diaphragm.

[0016] A first section 24 of the drive rod 6 is slidably arranged in the housing 20 along a feed axis 26. An electromechanical drive unit 30 comprises an electric motor (not shown) which drives an axially movable second section 34 of the drive rod 6. The housing 20 includes a connection area that corresponds to a connection area of ​​the drive unit 30. For example, the housing 20 includes an internal thread into which an external thread of the drive unit 30 can be screwed. The connection areas for connecting the housing 20 to the drive unit 30 are essentially rotationally symmetrical with respect to the feed axis 26, so that in an operating state of the valve actuator 2, the two sections 24 and 34 are arranged coaxially with respect to each other and lie on the feed axis 26.

[0017] The first section 24 comprises a distal first coupling contour 28, which corresponds to a distal second coupling contour 38 of the second section 34 such that a positive-locking connection of the two sections 24 and 34 of the drive rod 6 exists in the operating state of the valve actuator 2. The two sections 24 and 34 are connected to each other along the feed axis 26 with virtually no play.

[0018] In one assembly state of the valve actuator 2, the actuator unit 30 is unscrewed from the housing 20 and thus removed from the housing 20. If the distal end of a connecting section 40 of the actuator unit 30 is led out of a distal opening of the housing 20, the second coupling contour 38 can be displaced in an imaginary perpendicular plane 42 of the feed axis 26 and thus removed from the coupling contour 28. Thus, by a lateral movement of the actuator unit 30, the two sections 24 and 34 of the actuator rod 6 are separated from each other, allowing the individual assemblies, such as the preload assembly 12, the actuator unit 30, and / or the housing 20, to be exchanged.

[0019] A guide piston 44 is rigidly connected to the first section 24 and is movably mounted along the feed axis 26 within a guide space which is released by the housing 20.

[0020] Figure 2Figure 1 shows a schematic perspective view of a section of the drive unit 2. The first coupling contour 28 provides an undercut into which the flat cylindrical second coupling contour 38 engages. The undercut of the first coupling contour 28 includes a lateral opening 50. In an assembly direction 52, the coupling contour 38 is inserted into the coupling contour 28. In a disassembly direction 54, the coupling contour 38 is removed from the coupling contour 28. The coupling contours 28 and 38 are shown only as examples and can, of course, be designed differently, for example, interchanged with each other.

[0021] Figure 3 Figure 1 shows a schematic sectional view of a valve with a valve actuator 2 and a valve body 4, where the valve actuator 2 is screwed onto the valve body 4. The diaphragm 3 shown is a so-called PD diaphragm (PD: Plug Diaphragm), as is also used in the valve described in Figure 2. Figure 1and 2 The valve shown is used. In addition to the one already mentioned... Figure 1 The preload assembly 12 described above comprises the valve actuator 2 shown, which includes an actuator assembly 302 with a pneumatic piston 304 rigidly connected to the actuator rod 6 and which moves in a travel space along the feed axis 26. The pneumatic piston 304 divides the travel space into a distal chamber 306 and a proximal chamber 308. A spring element 310 pushes the pneumatic piston 304 distally away from the valve body 4, so that the valve is in a normally open state. If the pressure in the distal chamber 306 is increased via a control air channel 312, the actuator rod 6 and thus the diaphragm 3 move towards the valve seat.

[0022] The control air channel 312 connects the distal chamber 306 and a control air port 314, which is connected to a surface 316 distally bounding the housing 20. The control air port 314 can, of course, also project beyond the distal surface 316. Furthermore, the distal surface 316 can also be inclined. Naturally, the longitudinal axis 318 of the control air port 314 can also be inclined relative to the feed axis 26, rather than running parallel to it as shown. In addition, the compressed air can also be redirected via an angled compressed air port. The control air port 314 is radially spaced from the feed axis 26 and is thus located between a distal edge region 320 of the distal surface 316 and the center of the upper part of the housing 20, which is located in the region of the feed axis 26.The off-center arrangement of the control air connection creates space for the integration of additional functions such as a stroke limiter.

[0023] Figure 4 Figure 1 shows a schematic sectional view of a valve with valve actuator 2 and valve body 4 in an example. In contrast to Figure 3The control air channel 312 leads from the control air port 314 into the proximal chamber 308. A spring 402 pushes the pneumatic piston 304, and thus the actuator rod 6, towards the valve seat, resulting in a normally closed state of the valve. The control air channel 312 includes a bore 404 extending from the proximal side of a housing section 406 of the housing 20, which is connected distally to the control air port 314. Furthermore, the bore 404 is connected to the proximal chamber 308 via an inwardly extending opening 408. A proximal housing section 410 includes a distal connection area 412, which corresponds to a connection area 414 of the distal housing section 406. The bore 404 extending from the connection area 414 is a blind hole.

Claims

1. Valve drive (2) for a valve which limits a flow of a process fluid, the valve drive (2) comprising: a first portion (24) of a drive rod (6) having a first coupling contour (28), which first portion is displaceable along a feed axis (26) and can be arranged in a housing (20), an electromotive drive unit (30) having an axially movable second portion (34) of the drive rod (6), the second portion (34) of the drive rod (6) comprising a second coupling contour (38), the first and the second coupling contour (28, 38) engaging in a form-fitting manner along the feed axis (26) in an operating state of the valve drive (2) in which the housing (20) and the drive unit (30) are fixed with respect to each other, characterized in that, in an assembly state of the valve drive (2) in which the housing (20) and the drive unit (30) are not fixed with respect to each other, the second coupling contour (38) can be removed from the first coupling contour (28) and can be coupled to the first coupling contour (28), and in that, in the assembly state of the valve drive (2), the second coupling contour (38) is displaceable in an imaginary perpendicular plane (42) of the feed axis (26) with respect to the first coupling contour (28), such that the second coupling contour (38) can be separated from the first coupling contour (28) by a lateral movement of the drive unit (30).

2. Valve drive (2) according to claim 1, wherein the first coupling contour (28) and the second coupling contour (38) are connected to each other along the feed axis (26) with almost no backlash.

3. Valve drive (2) according to any of the preceding claims, wherein the valve drive (2) comprises: a first housing connection region of the housing (20) in which the first portion (24) of the drive rod (6) is displaceably fixed axially along the feed axis (26), a second housing connection region of the drive unit (30), wherein the first housing connection region corresponds to the second housing connection region, such that, in the operating position, the first and second portion (24, 34) of the drive rod (6) lie on the common feed axis.

4. Valve drive (2) according to claim 3, wherein the second connection region provides a thread into which a corresponding mating thread of the first connection region can be screwed.

5. Valve drive (2) according to any of the preceding claims, wherein a non-self-locking gear is arranged between an electric motor of the drive unit (30) and the second coupling contour (38) of the second portion (34).

6. Valve drive (2) according to any of claims 1 to 4, wherein a self-locking gear is arranged between an electric motor of the drive unit (30) and the second coupling contour (38) of the second portion (34).

7. Valve drive (2) according to claim 6, wherein the second portion (34) of the drive rod (6) can be extended by means of the electric motor, wherein the second coupling contour (38) of the extended second portion (34) can be coupled to the first coupling contour (28), wherein the second portion (34) coupled to the first portion (32) can be retracted by means of the electric motor, and wherein the drive unit (30) comprising the coupled first and second portions (24, 34) can be fixed with respect to the housing.

8. Valve drive (2) according to any of the preceding claims, wherein the first portion (24) of the drive rod (6) is rigidly connected to a guide piston (44), and wherein the guide piston (44) is movably mounted along the feed axis (26) within a guide space which the housing (20) provides, and / or wherein a preload assembly (12) for arrangement between the drive unit (30) and a diaphragm (3) is arranged in the housing (20).

9. Valve drive (2) according to claim 8, wherein the guide piston (44) is arranged between the drive unit (30) and the preload assembly (12).

10. Valve drive (2) according to claim 8 or 9, wherein a spring element (22) of the preload assembly (12) holds the preload assembly (12) in a preloaded state before insertion into the housing (20).

11. Valve drive (2) according to claim 10, wherein the spring element (22) is designed, after the preload assembly (12) has been inserted into the housing, to clamp a diaphragm (3) between the preload assembly (12) and a valve body (4).

12. Valve drive (2) according to any of the preceding claims, wherein the housing (20) has a thread which faces away from the drive unit (30) and can be screwed into a mating thread of the associated valve body (4), and / or wherein the preload assembly (12) is supported in a diameter recess of the housing (20).

13. Valve drive (2) according to any of claims 8 to 12, wherein the preload assembly (12) comprises a counter bearing portion and a clamping portion for clamping the diaphragm (3), wherein the clamping portion is supported on the counter bearing portion by means of the loaded spring element (22), wherein the clamping portion comprises a first stop region in a portion that projects through a through-opening of the counter-bearing portion, and wherein, in the preloaded state of the preload assembly (12), a second stop region of the counter bearing portion, in conjunction with the first stop region of the clamping portion, limits a movement of the clamping portion away from the counter bearing portion.

14. Valve drive (2) according to any of claims 8 to 13, wherein the first portion (24) of the drive rod (6) is displaceably guided within the preload assembly (12) along the feed axis (26), and / or wherein the first portion (24) of the drive rod (6) is captively arranged in the preload assembly (12).

15. Valve comprising a valve drive (2) according to any of the preceding claims.