Drive rod, process valve drive, process valve, and method for operating the process valve

Abstract

A drive rod (10) for a process valve drive (300) is provided.The drive rod (10) comprises at least a first section (100) comprising a drive interface (130) by means of which at least a part of a drive force emanating from the process valve drive (300) can be introduced into the drive rod (10) for its movement along an actuating axis (S), and comprising a first connection interface (110); and at least a second section (200) comprising a second connection interface (210), wherein the second connection interface (210) together with the first connection interface (110) is configured for the rigid attachment of the at least one second section (200) to the first section (100), and wherein the second section (200) comprises at least one sensor (400) which is configured to generate a signal (S_400) which characterizes a force acting on the second section (200) along the actuating axis (S).

Description

[0001] The invention relates to an actuator rod for a process valve actuator, the process valve actuator, a process valve and a method for operating the process valve.

[0002] The problems of the prior art are solved by an actuator rod, a process valve actuator, a process valve and a method for operating the process valve according to the respective independent or dependent claims.

[0003] A first aspect of the description relates to an actuator rod for a process valve actuator. The actuator rod comprises: at least one first section comprising a drive interface, by means of which at least part of a drive force emanating from the process valve actuator can be introduced into the actuator rod for its movement along an actuating axis, and comprising a first connection interface; and at least one second section comprising a second connection interface, wherein the second connection interface, together with the first connection interface, is configured for rigidly fastening the at least one second section to the at least one first section, and wherein the at least one second section comprises at least one sensor configured to generate a signal characterizing a force acting on the at least one second section along the actuating axis.

[0004] The first and second sections provide at least two components which, together and rigidly connected, form the drive rod. This modular division of the drive rod into the two sections makes it possible to carry out drive-specific adaptations of the drive interface regardless of the design of the second section. Consequently, it is possible to use identical second sections for first sections that have a different design compared to the drive interface. This results in degrees of freedom for the design of the drive interface. For example, in the case of a screw drive, different thread pitches can be provided in order to adapt the design of the respective drives. In the case of pneumatic drives, the arrangement of a drive piston can be carried out independently of the design of the sensor.Advantageously, different drive concepts, such as an electric drive and a pneumatic drive, can use the same modular system with only one or a few different versions of the second section. Furthermore, valve actuators can also be retrofitted with the section that contains at least one sensor if one is not already present. Furthermore, the second section can be easily replaced without dismantling the remaining parts of the actuator.

[0005] Furthermore, this precise force feedback from the actuator stem core enables the desired actuator control. Since the actual force is known, a desired opening or closing force can be specified depending on the operating state to control the actuator accordingly. Furthermore, position feedback can be used to further fine-tune force control, for example, to apply increased force to the actuator stem and thus also to the shut-off body in certain positions, such as the closed position.

[0006] Alternatively or additionally, valve monitoring is improved. This makes it possible to allow only a certain maximum force in certain operating conditions. For example, increased force during the closing process indicates the presence of a foreign object in the valve. Furthermore, force peaks in the open, stationary state can indicate pressure surges at other points in the process plant.

[0007] An advantageous example is characterized in that the second section of the actuator rod comprises a third connection interface, which is designed for the force-conducting connection of the second section to a shut-off means of the process valve, to a compressor or pressure piece of the process valve or to another section of the actuator rod, wherein the sensor is arranged in the force path between the second connection interface and the third connection interface.

[0008] This makes it possible to advantageously measure the forces that occur between the drive interface and the third connection interface.

[0009] An advantageous example is characterized in that the second section has a material taper in its course, wherein the at least one sensor is arranged in the region of the material taper.

[0010] The forces introduced into the second section, either from the drive side or from the shut-off body side, lead to material distortions in the second section. The material taper advantageously concentrates these distortions so that they can be better detected by sensors.

[0011] An advantageous example is characterized in that the second section comprises a groove base at least in sections, in particular in the area of ​​the material taper, wherein the sensor is arranged on the groove base.

[0012] The second section is advantageously designed to be tapered but stable. Furthermore, the force can be directed precisely into the sensor, which is particularly facilitated by the symmetrical design with the groove base and surrounding side strips.

[0013] An advantageous example is characterized in that at least one signal line, which electrically contacts the at least one sensor and is led out at a distal opening of the first section, is arranged in sections within a first through-opening of the first section and in sections within a second through-opening of the second section

[0014] This makes it easy to route the signal line to the outside.

[0015] An advantageous example is characterized in that the second through-opening of the second section is arranged radially inside the second connection interface with respect to the adjusting axis.

[0016] The collinear arrangement of the second connection interface and the second through-opening advantageously helps to compact the drive in height or along the actuating axis.

[0017] An advantageous example is characterized in that the first connection interface of the first section is arranged radially inside the drive interface with respect to the actuating axis.

[0018] The collinear arrangement of the first connection interface and the drive interface advantageously helps to compact the drive in height or along the actuating axis.

[0019] An advantageous example is characterized in that the at least one sensor is arranged in a space which is fluid-tight starting from the at least one sensor and pointing away from the first section.

[0020] This effectively prevents the penetration of process fluid into the sensor area.

[0021] An advantageous example is characterized in that the rigid connection between the first connection interface and the second connection interface is detachable.

[0022] The proposed modularity and detachable connection offer advantages in maintenance and resource consumption. Drives are subject to a certain degree of aging, which is particularly evident in the area of ​​the drive interface of the drive rods. When replacing the first section, the second previously installed section can be retained. The same applies the other way around, i.e., when replacing the second section. Consequently, resource consumption is reduced.

[0023] An advantageous example is characterized in that the second section is incorporated in sections into the first section.

[0024] Advantageously, a purely sequential design of the actuator rod can be avoided and the height of the valve actuator can be reduced.

[0025] An advantageous example is characterized in that the first connection interface of the first section is arranged between the drive interface of the first section and the second connection interface of the second section.

[0026] The actuator interface thus surrounds the two connection interfaces and enables a compact design of the valve.

[0027] An advantageous example is characterized in that the process valve actuator according to a second aspect of the description comprises a nut rotatable relative to the actuator rod, wherein the drive interface and the nut define common grooves for balls, wherein at least one return channel for the balls is designed within the rotatable nut.

[0028] Advantageously, a ball screw drive with a force measurement in the area of ​​the drive rod is provided.

[0029] As an alternative to the proposed ball screw, a trapezoidal screw drive or any screw drive can be used to couple the drive force from the process valve actuator to the actuator stem.

[0030] An advantageous example is characterized in that the rotatable nut is part of a rotor of an electric motor, wherein the rotor is arranged between the drive rod and a stator of the electric motor.

[0031] A third aspect of the description concerns the process valve itself.

[0032] A fourth aspect of the description relates to a method for operating the process valve according to the third aspect, wherein the method comprises: determining a control signal as a function of the at least one signal that characterizes the force acting on the second section along the actuating axis, and as a function of at least one predetermined target value, in particular a target value for the force on the at least second section; operating the process valve drive as a function of the determined control signal.

[0033] The drawing shows: Fig. 1 a schematic representation of a process valve; Fig. 2 an actuator rod for the process valve in a perspective sectional view; Fig. 3 a second section of the drive rod in a side view; Fig. 4 the second section in a perspective view; and Fig. 5 a process valve actuator in a sectional view.

[0034] Fig. 1 shows a schematically illustrated process valve 2 in a section in which an actuating axis S of the process valve 2 lies. The process valve 2 comprises a shut-off body 4, which can be pressed onto a valve seat 6 of a valve body 8 by means of a process valve actuator 300 and can be moved away from the valve seat 6. To move the shut-off body 4, the shut-off body 4 is connected to the process valve actuator 300 by means of an actuating rod 10. The process valve actuator 300 introduces a force into the actuating rod 10 in order to move it along the actuating axis S according to the double arrow 11. The actuating rod 10 comprises a connecting interface 280 in order to force-transmit the shut-off body 4 to the actuating rod 10.

[0035] The process valve 2 is designed as a diaphragm valve. For example, a diaphragm pin 12 protrudes from the shut-off body 4, which is designed as a valve diaphragm, and is force-transmittingly connected to the actuator stem 10 via the connection interface 280. The process valve actuator 300 comprises a housing 14, with the valve diaphragm clamped between the housing 14 and the valve body 8. Of course, any other type of process valve 2, such as a seat valve, a control valve, etc., in particular a butterfly valve, can be equipped with the described actuator stem 10. The preceding paragraph is therefore also applicable to valve types other than the diaphragm valve shown.

[0036] Fig. Figure 2 shows the actuator rod 10 for the process valve in a perspective sectional view. The actuator rod 10 for the process valve actuator 300 comprises at least a first section 100 comprising a drive interface 130, by means of which at least a portion of a drive force emanating from the process valve actuator 300 can be introduced into the actuator rod 10 for its movement along an actuating axis S. The actuator rod comprises a first connection interface 110.The drive rod 10 comprises at least one second section 200 comprising a second connection interface 210, wherein the second connection interface 210 together with the first connection interface 110 is configured for rigidly fastening the at least one second section 200 to the at least one first section 100, and wherein the at least one second section 200 comprises at least one sensor 400 which is configured to generate a signal S_400 which characterizes a force acting on the at least one second section 200 along the actuating axis S.

[0037] The second section 200 of the actuator rod 10 comprises the third connection interface 280, which is designed for the force-conducting connection of the second section 200 to a shut-off means 4 of the process valve 2, to a compressor or pressure piece of the process valve 2 or to another section of the actuator rod 10, wherein the sensor 400 is arranged in the force path between the second connection interface 210 and the third connection interface 280.

[0038] The at least one sensor 400 is arranged in a space 420, which is fluid-tight starting from the at least one sensor 400 and pointing away from the first section 400. The at least one sensor 400 is arranged, for example, in the region of a material taper in order to adapt the measuring range, see Fig. 3. Alternatively, the material taper can be omitted, for example at higher forces.

[0039] For example, a gap of 422 in Fig. 2 is provided with an O-ring or a cylinder jacket-shaped seal, thus providing the space 420, whose only opening to the outside is the distal opening 102. Alternatively or additionally, the intermediate space 422 functions as a sliding guide and centering between the first section 100 and the second section 200 and can thus serve to absorb radial forces.

[0040] The rigid connection between the first connection interface 110 and the second connection interface 210 is detachable. As shown in the example, the aforementioned rigid connection is designed as a screw connection, with an external thread in the sense of the second interface 210 of the second section 200 engaging an internal thread in the sense of the first interface 110 of the first section 100.

[0041] The second section 200 is partially accommodated in the first section 100. The first section 100 thus surrounds the second section 200 in sections. The first connection interface 110 of the first section 100 is arranged in the radial direction relative to the actuating axis between the drive interface 130 of the first section 100 and the second connection interface 210 of the second section 200.

[0042] The process valve actuator 300 comprises a nut 310 rotatable relative to the actuator rod 10, wherein the drive interface 130 and the nut 310 jointly define at least one raceway for balls, wherein at least one return channel for the balls is formed between ends of the at least one raceway within the rotatable nut 310.

[0043] The example shows a recirculating ball nut. Of course, the drive rod 10 can also be driven by a trapezoidal thread or other means for movement along the actuating axis.

[0044] Fig. Figure 3 shows the second section 200 in a side view. The second section 200 has a material taper 240 along its length, with the at least one sensor 400 being arranged in the region of the material taper 240.

[0045] The second section 200 comprises, at least in sections, particularly in the area of ​​the material taper 240, two freestanding side strips 242a-b and a groove base 244 arranged between the side strips 242a-b. The groove base 244 is provided, for example, by one of two opposing grooves in the second section. The sensor 400 is arranged on the groove base 244, particularly on the surface of the groove base 244.

[0046] At least one pocket adjoins the respective side strip 242a-b, which further tapers the material to improve the measuring range of the at least one sensor 400. In particular, the respective side strip 242a-b is surrounded by two pockets.

[0047] In the example shown, the side strips 242a-b run in a first spatial orientation, as does the groove base 244.

[0048] At least one groove wall that defines a groove with the groove base 244 extends in a second spatial orientation. The first and second spatial orientations are, in particular, orthogonal to one another.

[0049] The side strips 242a-b extend parallel to the adjustment axis S over an area in which the at least one sensor 400 is also arranged.

[0050] The at least one sensor 400 is designed, for example, as a strain gauge and is arranged on the surface of the groove base 244.

[0051] In one example, two sensors 400 are provided, with the first sensor 400 being arranged on the groove bottom 244 and the second sensor being arranged on a further groove bottom opposite the groove bottom 244. In an arrangement without a groove bottom, the two sensors 400 are arranged on the surface of the second section 200.

[0052] A single sensor arrangement is useful when measurement errors are tolerated. A two-sensor arrangement is advantageous because measured transverse forces cancel each other out by simply averaging the generated sensor signals or the forces derived from them.

[0053] At least one signal line 410 electrically contacts the at least one sensor 400. The at least one signal line is routed out of the distal opening 102 of the first section 100. The at least one signal line 410 is arranged in sections within a first through-opening 104 of the first section 100 and in sections within a second through-opening 202 of the second section 200.

[0054] A through-hole 224 extends perpendicular to the adjustment axis S, into which the through-hole 202 opens on the sensor side and in which the groove base 244 ends. The signal line 410 is terminated, for example, in the region of the through-hole 224 and electrically contacted with at least one sensor 400.

[0055] The second through-opening 202 of the second section 200 is arranged radially within the second connection interface 210 with respect to the adjustment axis S. The first connection interface 110 of the first section 100 is arranged radially within the drive interface 130 with respect to the adjustment axis S.

[0056] Fig. 5 shows a schematic section of the process valve actuator 300. The rotatable nut 310 is part of a rotor 342 of an electric motor, wherein the rotor 342 is arranged between the drive rod 10 and a stator 344 of the electric motor.

[0057] The drive rod 10 is mounted on the housing 14 for its linear movement along the actuating axis S by means of two spaced-apart bearing sections 362 and 364. The bearing sections 352 and 354 are located between the bearing sections 362 and 364.

[0058] A rotatable sensor section 370 is rigidly connected to the rotor 310. The rotatable sensor section 370 is provided with a permanent magnet, while a stationary sensor section (not shown) registers the changing magnetic field created by the rotation and generates a rotation signal for position detection.

[0059] A rotatable gear ring 380 is rigidly connected to the rotor 310. The gear ring engages a gear 382 of a shaft 386 connected to a brake 384. The brake 384 ensures that the drive position is not changed when the electric drive is inactive.

[0060] A control unit 500 implemented on at least one circuit board evaluates the signal S_400 and operates the electric drive in response to the signal S_400. In particular, the stator 344 is controlled.

[0061] An exemplary method for operating the process valve 2 comprises a Determining a control signal S_300 as a function of the at least one signal S_400, which characterizes the force acting on the second section 200 along the actuating axis S, and as a function of at least one predetermined target value, in particular a target value for the force on the at least second section 200. The method comprises operating the process valve actuator 300 as a function of the determined control signal S_300.

Claims

[1] An actuator rod (10) for a process valve actuator (300) comprising: at least one first section (100) comprising a drive interface (130), by means of which at least a part of a drive force emanating from the process valve drive (300) can be introduced into the drive rod (10) for its movement along an actuating axis (S), and comprising a first connection interface (110); and at least one second section (200) comprising a second connection interface (210), wherein the second connection interface (210) together with the first connection interface (110) is configured for rigidly fastening the at least one second section (200) to the at least one first section (100), and wherein the at least one second section (200) comprises at least one sensor (400) which is configured to generate a signal (S_400) which characterizes a force acting on the at least one second section (200) along the actuating axis (S). [2] The drive rod (10) according to claim 1, wherein the second section (200) of the drive rod (10) comprises a third connection interface (280) which is designed for the force-conducting connection of the second section (200) to a shut-off body (4) of the process fitting (2), to a compressor or pressure piece of the process fitting (2) or to a further section of the drive rod (10), and wherein the sensor (400) is arranged in the force path between the second connection interface (210) and the third connection interface (280). [3] The drive rod (10) according to one of the preceding claims, wherein the second section (200) has a material taper (240) in its course, and wherein the at least one sensor (400) is arranged in the region of the material taper (240). [4] The drive rod (10) according to one of the preceding claims, wherein the second section (200) comprises a groove bottom (244) at least in sections, in particular in the region of the material taper (240), wherein the sensor (400) is arranged on the groove bottom (244). [5] The drive rod (10) according to one of the preceding claims, wherein at least one signal line (410), which electrically contacts the at least one sensor (400) and is led out at a distal opening (102) of the first section (100), is arranged in sections within a first through-opening (104) of the first section (100) and in sections within a second through-opening (202) of the second section (200). [6] The drive rod (10) according to the preceding claim, wherein the second through-opening (202) of the second portion (200) is arranged radially inside the second connection interface (210) with respect to the actuating axis (S). [7] The drive rod (10) according to one of the preceding claims, wherein the first connection interface (110) of the first section (100) is arranged radially inside the drive interface (130) with respect to the actuating axis (S). [8] The drive rod (10) according to one of the preceding claims, wherein the at least one sensor (400) is arranged in a space (420) which is fluid-tight starting from the at least one sensor (400) and pointing away from the first section (400). [9] The drive rod (10) according to one of the preceding claims, wherein the rigid connection between the first connection interface (110) and the second connection interface (210) is detachable. [10] The drive rod (10) according to one of the preceding claims, wherein the second section (200) is partially received in the first section (100). [11] The drive rod (10) according to one of the preceding claims, wherein the first connection interface (110) of the first section (100) is arranged perpendicular to the actuating axis (S) between the drive interface (130) of the first section (100) and the second connection interface (210) of the second section (200). [12] A process valve actuator (300) comprising the actuator rod (10) according to one of the preceding claims. [13] The process valve actuator (300) according to claim 12, wherein the process valve actuator (300) comprises a nut (310) rotatable relative to the actuator rod (10), wherein the drive interface (130) and the nut (310) define common grooves for balls, and wherein at least one return channel for the balls is formed within the rotatable nut (310). [14] The process valve actuator (300) according to claim 13, wherein the rotatable nut (310) is part of a rotor (342) of an electric motor, the rotor (342) being arranged between the drive rod (10) and a stator (344) of the electric motor. [15] A process valve (2) comprising the process valve drive (300) according to one of claims 12 to 14. [16] A method for operating the process valve (2) according to the preceding claim, the method comprising: Determining a control signal (S_300) as a function of the at least one signal (S_400) which characterizes the force acting on the second section (200) along the actuating axis (S), and as a function of at least one predetermined target value, in particular a target value for the force on the at least second section (200); Operating the process valve actuator (300) depending on the determined control signal (S_300).

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