Magnetic compensators for pneumatic positioners

Abstract

A magnetic compensator is disclosed for at least partially compensating for a closing force required to move a valve of a pneumatic positioner to a closed position, the magnetic compensator having a magnetic component comprising a permanent magnet; and a magnetic mating piece; wherein the magnetic component and the magnetic mating piece are configured to interact to generate an attractive force for at least partially compensating for the closing force; and wherein the magnetic compensator is configured to be mechanically coupled to the valve of the pneumatic positioner.

Description

Technical Field

[0001] The present disclosure relates generally to magnetic compensators and, more particularly, to magnetic compensators for pneumatic positioners. Background Art

[0002] Today, more than 60% of all actuators used in the process industry are pneumatic based, which requires a positioner to control the position of the actuator.

[0003] To operate such a valve positioner, the "main stage" of the valve positioner is driven by a "pilot stage". The main stage is the unit that operates the pneumatic actuator, which operates the process valve at the required pneumatic operating pressure (e.g. 10 bar). The standard approach is to design the system comprising the valve positioner, the pneumatic actuator and the process valve so that the operating point of the main stage is close to a balance of forces, resulting in small changes in the control pressure to provide the required rapid closing of the valve (tripping of the valve). The valve positioner generally has to meet strict requirements for low energy consumption. The unit that controls the control pressure of the valve positioner, the "pilot stage", represents the controllable part of the system. The pressure for operating the pilot stage is a fraction of the pneumatic operating pressure of the pneumatic actuator and is provided by a pressure reducer. Summary of the Invention

[0004] Valve positioners with pneumatic outputs and their corresponding systems face two conflicting business requirements. On the one hand, high pneumatic pressure is required to operate the pneumatic actuator; on the other hand, there are stringent requirements for low power consumption for the entire system. To this end, conventional positioners consist of several submodules, which can be considered force amplifiers. However, this prior art arrangement results in a complex and bulky setup. To operate high pneumatic pressure with low power, particularly low electrical power, a near-balanced layout is employed, in which the pneumatic pressure force is balanced by, for example, a compensating spring. Consequently, only minimal force and the corresponding energy are sufficient to control the position of the process valve.

[0005] This small amount of "controlled force" is also typically based on pneumatic pressure. Therefore, a "pressure reducer" is used, which partially reduces the total pneumatic pressure to provide a low pressure to a subsystem designed to be controlled with low electrical power. This "low-pressure subsystem" is the "pilot stage." In other words, the pilot stage acts as a force amplifier, controlling the larger force of the pneumatic pressure with the smaller controlled force. The use of a pilot stage is often inefficient and costly. Previous power requirements led to designs with a balanced main stage and a controllable subunit (pilot stage) that controls a portion of the pneumatic pressure.

[0006] Prior art systems for valve positioners with pneumatic outputs operate using pilot stages, which can be configured in various ways and based on different technologies, such as piezoelectric nozzles or flapper nozzles. The use of pilot stages often results in bulky designs and is costly. Another issue with pilot stage designs for valve positioners is the constant blow-off of the pneumatic medium, which leads to low efficiency.

[0007] This problem can be overcome by using a positioner driver for controlling a valve positioner having a pneumatic output, wherein the positioner driver is configured to be mechanically coupled to a valve of the valve positioner having a pneumatic output for controlling the valve positioner having a pneumatic output.

[0008] In other words, by using this positioner driver, a valve positioner with a pneumatic output, or a unit of a main stage of a valve positioner with a pneumatic output system, is directly driven and / or operated by the positioner driver, thereby eliminating a pilot stage and / or a pressure reducer, thereby saving energy and / or having a smaller valve positioner system with a pneumatic output. This means that compared to a valve positioner system with a pneumatic output in the prior art, a valve positioner with a pneumatic output driven by a positioner driver can result in a reduced design space.

[0009] This direct actuation of the main stage unit by the positioner drive without the use of pneumatic pressure may be controlled by an electrical signal and / or electrical power provided to the positioner drive.

[0010] The positioner driver may be configured to be directly mechanically coupled to the plunger of a valve of a valve positioner having a pneumatic output to create a simple system using such a valve positioner having a pneumatic output including a positioner driver that may be directly electrically driven.

[0011] The concept of a valve that is directly positioned using a positioner actuator eliminates the pilot stage of the prior art, thereby reducing system complexity and increasing robustness.

[0012] Furthermore, the system becomes more controllable because each main stage component can be controlled individually, as opposed to one pilot stage controlling multiple main stage elements as in the prior art.

[0013] Such positioning drives may be based on electromagnetic actuators, where converting input electrical power into output mechanical power in terms of force and speed is a suitable candidate actuator technology.

[0014] A positioner drive that directly drives a valve positioner means that the actuator can be mechanically coupled directly to the moving part of the main stage without any mechanical transmission.

[0015] With conventional valve positioners, the valve is mechanically coupled to the valve's plunger, which is movably arranged within the valve positioner and results in a rod force being applied to hold the valve's plunger in a given position, thereby maintaining a certain valve clearance opening. With a positioner drive system that directly drives the valve positioner, this force must be provided by the positioner drive, for example, by an actuator of the positioner drive.

[0016] If the valve positioner's valve clearance is fairly open, the stem force can be controlled by the stiffness of the valve positioner's flexible seal. When the valve clearance is small, just before the valve closes, the stem force typically increases sharply to accommodate the remaining valve clearance, driving the valve positioner's seat into the sealing position. Therefore, the actuator must provide a high force during this phase.

[0017] Aspects of the present invention relate to a magnetic compensator, a positioner drive for controlling a pneumatic positioner, a positioner drive system, a valve positioner system and a use of a magnetic compensator.

[0018] All combinations of at least two features disclosed in the description, claims and drawings fall within the scope of the invention. To avoid repetitions, features disclosed with respect to the method will also apply with respect to the system and be claimable.

[0019] Throughout the description of the present invention, some features have count words to improve readability or make assignment clearer, but this does not imply the existence of certain features.

[0020] To achieve these and other advantages and in accordance with the purposes of the present invention, as embodied and broadly described herein, there is provided a magnetic compensator for at least partially compensating for a closing force required to move a valve of a pneumatic positioner to a closed position, the magnetic compensator having a magnetic component and a magnetic partner for the magnetic component, the magnetic component including a permanent magnet, wherein the magnetic component and the magnetic partner are configured to interact to generate an attractive force for at least partially compensating for the closing force; and wherein the magnetic compensator is configured to be mechanically coupled to the valve of the pneumatic positioner.

[0021] The attractive force may be generated by magnetic coupling between the magnetic component and the magnetic mating part.

[0022] Advantageously, a magnetic compensator can be used instead of a mechanical spring to provide the force required to compensate for the closing force, corresponding to the rod force, wherein the magnetic compensator can be configured to provide a closing force that is just strong enough to drive the valve into the sealing position, but the closing force can be configured to be no greater, so that the force required by the actuator can be minimized.

[0023] By using a magnetic compensator with a valve positioner and a positioner drive to compensate for the closing force, respectively the rod force, a system can be provided and configured, for example by means of an additional spring, wherein in the event of an operating failure of the positioner drive and / or in the event of no electrical power being supplied to the positioner drive, the valve of the valve positioner opens or closes.

[0024] Advantageously, the magnetic compensator can be configured via magnetic coupling between a magnetic component and a magnetic mating member separated by a magnetic gap to provide a force characteristic similar to the relationship between stem force and valve clearance. To compensate for stem forces, the magnetic compensator can be configured and / or arranged in parallel with a positioner actuator configured to operate the valve positioner. Alternatively, the magnetic component or magnetic mating member can be mechanically coupled directly to the valve positioner to at least partially compensate for stem forces.

[0025] According to one aspect, the magnetic partner comprises a ferromagnetic material configured to interact with the magnetic component and / or comprises another permanent magnet configured to interact with the magnetic component.

[0026] Advantageously, by configuring the magnetic mating members as described above, the magnetic coupling can be tailored to the relationship between the stem force required to move the valve of the valve positioner and the valve.

[0027] According to one aspect, the magnetic component comprises a yoke arranged and configured to increase the attractive force and / or to adapt the relationship of the attractive force to the valve movement to the relationship of the closing force to the valve movement.

[0028] Advantageously, by configuring and / or shaping and / or arranging the yoke of the magnetic component, the magnetic coupling relationship between the magnetic component and the magnetic mating piece can be adapted to the relationship between the stem force and the valve clearance.

[0029] According to one aspect, the magnetic component is shaped as a ring.

[0030] The magnetic field of the magnetic component can be oriented perpendicular to the direction of movement of the plunger of the valve.

[0031] According to a further aspect, the yoke of the magnetic component is shaped as a ring and / or a disk.

[0032] The use of a magnetic component in the form of a yoke facilitates adaptation of the magnetic compensator to the specific needs of compensating the rod forces.

[0033] According to one aspect, the magnetic member includes a pole face adjacent to the permanent magnet to adapt the attractive force-to-valve movement relationship to a closing force-to-valve movement relationship.

[0034] Combining the magnetic components with specifically formed and arranged pole faces enables the magnetic compensator to be adapted to the rod force versus valve clearance relationship.

[0035] According to one aspect, the magnetic component includes a plurality of permanent magnet units magnetically coupled to a yoke.

[0036] In other words, the yoke may embed a plurality of permanent magnets, which may be evenly distributed within the yoke, in particular with respect to rotational symmetry.

[0037] According to one aspect, the magnetic compensator includes an adjustment device configured to adjust the magnetic coupling between the magnetic component and the magnetic mating piece to adapt the attractive force-to-valve movement relationship to the closing force-to-valve movement relationship.

[0038] Advantageously, such an adjustment device can be used to compensate for practical assembly and material tolerances. The adjustment device can be used to alter the characteristics of the relationship between the magnetic force and the magnetic force. A simple example of an adjustment device could be a device that adjusts the magnetic gap between the magnetic component and the magnetic mating part by changing the distance between the magnetic component and / or the magnetic mating part. This can be used to adjust the valve clearance to the magnetic gap and / or adjust the relationship between the magnetic force and the magnetic gap to the relationship between the rod force and the valve clearance.

[0039] According to one aspect, the magnetic compensator is arranged relative to the valve of the pneumatic positioner and is configured to lock the valve in the event of an operational failure of a positioner drive for controlling the pneumatic positioner; or to open the valve to control the pneumatic positioner in the event of an operational failure of the positioner drive.

[0040] The magnetic compensator may accordingly be provided by a spring to hold the valve open or closed in the event of an operational failure of the positioner actuator, ie a "fail-to-close", and / or to provide a shutdown state of the positioner actuator.

[0041] Thus, a defined condition in the unpowered state is provided for forcing the valve of the valve positioner to a closed and sealing position.

[0042] According to one aspect, a pneumatic positioner includes a dielectric elastomer actuator for controlling the pneumatic positioner.

[0043] Advantageously, this provides a compact design of the positioner drive and can be combined with a magnetic compensator.

[0044] To this end, the valve positioner may include a membrane actuator configured with a dielectric elastomer to control the valve positioner.

[0045] According to one aspect, a valve positioner with a pneumatic output includes a first dielectric elastomer membrane and a second dielectric elastomer membrane, wherein each dielectric elastomer membrane is mechanically coupled to a valve of the valve positioner with a pneumatic output for controlling the pneumatic positioner.

[0046] According to one aspect, the membrane actuator is configured to be directly mechanically coupled to a plunger of a valve of a pneumatic positioner.

[0047] This direct mechanical coupling to the plunger of the valve enables the use of such a valve positioner with a pneumatic output to create a simple system comprising a positioner driver which can be driven directly by the electrical signal supplied to the membrane actuator.

[0048] According to one aspect, a membrane actuator is configured to seal a pneumatic chamber of a pneumatic positioner.

[0049] According to one aspect, a membrane actuator includes a dielectric elastomer membrane; and at least one electrode adjacent to the dielectric elastomer membrane to control the membrane actuator based on a voltage supplied to the electrode.

[0050] Dielectric elastomer actuators (DEAs) are members of the group of "unconventional actuators" based on smart materials. Advantageously, DEAs have a proven track record in various applications and can be adapted for the described purpose. A potential solution is to use DEAs in a membrane configuration, which allows for the functional integration of pressure sealing, mechanical guidance, and actuation.

[0051] The DEA comprises an elastic membrane, such as silicon, with electrodes on each side for applying an electric field. This arrangement resembles a conventional capacitor, but with an elastic dielectric material between the electrodes. When the electric field is activated, the force compresses the elastic dielectric material, thereby stretching the membrane actuator. Using this membrane actuator arrangement, the electric field allows the membrane to be elongated and allows for out-of-plane motion of the membrane actuator, which can directly operate a main-stage valve, such as one within a pneumatic positioner.

[0052] This means that a valve positioner with a pneumatic output or a valve positioner with a pneumatic output unit of the main stage can be operated directly by a dielectric elastomer actuator (DEA) in a "membrane layout", ideally with the sealing and actuating functions integrated by the DEA.

[0053] According to one aspect, a membrane actuator includes an electrical counter electrode adjacent to the dielectric elastomer membrane at a side of the dielectric elastomer membrane opposite the electrical electrode for generating an electric field between the electrodes when a voltage is applied to the electrodes.

[0054] According to one aspect, a membrane actuator includes: a first electrical contact electrically coupled to an electrode; and a second electrode having a second electrical contact; for providing a voltage to operate the membrane actuator.

[0055] According to one aspect, a membrane actuator is configured to be disposed within a housing of a pneumatic positioner.

[0056] The construction of the pneumatic positioner, in which the positioner driver is located within the housing of the valve positioner with pneumatic output, enables a compact design of the pneumatic positioner.

[0057] According to one aspect, a membrane actuator is configured to be mechanically coupled to a housing of a valve positioner having a pneumatic output for controlling the pneumatic positioner.

[0058] The peripheral portion of the membrane actuator may be connected to a housing of a valve positioner having a pneumatic output for enabling out-of-plane motion of the membrane actuator to move a valve of the pneumatic positioner.

[0059] According to one aspect, a dielectric elastomer membrane is configured to seal an internal pneumatic chamber of a valve positioner having a pneumatic output from an environment external to the valve positioner having a pneumatic output relative to a pneumatic fluid within the pneumatic chamber.

[0060] A positioner drive system for a control valve positioner is provided, the positioner drive system comprising the electromagnetic actuator and the magnetic compensator as described above, wherein the electromagnetic actuator is based on the electromagnetic Lorentz effect and / or the electromagnetic magnetoresistance effect.

[0061] A valve positioner system is provided, comprising a valve positioner and a positioner drive system, as described above, wherein the positioner drive system is mechanically coupled to a valve of the valve positioner for controlling the valve positioner.

[0062] The use of a magnetic compensator comprising a magnetic component and a magnetic mating element as described above is proposed for at least partially compensating a closing force required to move a valve of a valve positioner into a closed position.

[0063] As an embodiment of the present invention, there is provided a force compensator configured to form an integral part of a positioner drive system.

[0064] Therefore, alternatively or additionally, a positioner driver for controlling a valve positioner is provided, comprising an electromagnetic actuator and a magnetic compensator, as described above, wherein an actuator-yoke of the electromagnetic actuator includes a magnetic component of the magnetic compensator as an integral part of the actuator-yoke. Furthermore, the positioner driver comprises a magnetic mating member of the magnetic compensator, the magnetic mating member being mechanically coupled to a valve of the valve positioner for controlling the valve positioner.

[0065] The magnetic component may include a permanent magnet for generating a magnetic coupling between the magnetic component and the magnetic partner.

[0066] This may result in a compact assembly of the positioner drive including the magnetic compensator, but due to the integrated design, the integration of the magnetic compensator with the positioner drive does not allow for adjusting the magnetic compensator to production tolerances.

[0067] Alternatively or additionally, a positioner driver for controlling a valve positioner may include a magnetic compensator as described above, and an electromagnetic actuator including an actuator-yoke configured as a magnetic partner of the magnetic compensator, wherein the magnetic component of the magnetic compensator is coupled to a valve of the valve positioner. The magnetic component may include a permanent magnet for generating a magnetic coupling between the magnetic component and the magnetic partner.

[0068] This can result in a compact assembly of the positioner drive including the magnetic compensator, but due to the integrated design, the integration of the magnetic compensator with the positioner drive does not allow for adjustment of the magnetic compensator to production tolerances. However, the individual optimization of the different functions of the valve positioner with an integrated magnetic compensator becomes more challenging.

[0069] In other words, by using this positioner actuator, a valve positioner and / or a valve positioner system and / or a valve positioner with an integrated magnetic compensator and / or a main stage unit of a valve positioner system with a pneumatic output is directly driven and / or operated by the positioner actuator, thereby eliminating a pilot stage and / or a pressure reducer, thereby saving energy and / or providing a valve positioner system with a pneumatic output with a smaller size. This means that compared to a valve positioner system with a pneumatic output in the prior art, the valve positioner with a pneumatic output can be designed with a reduced design space.

[0070] This direct actuation of the positioner drive without using pneumatic pressure to operate the main stage unit may be controlled by an electrical signal and / or electrical power provided to the positioner drive.

[0071] Advantageously, a valve positioner mechanically coupled to a positioner actuator provides a robust system because it can be constructed with a less complex mechanical structure. Furthermore, such a valve positioner with a pneumatic output can be configured to be more robust to temperature variations and external vibrations than a pneumatic pilot stage, making it suitable for use in a variety of production environments. Using a pneumatic output to drive the valve positioner directly reduces the air quality requirements of the entire pneumatic system because it is less sensitive to airborne particles that could become lodged in, for example, a pneumatic pilot stage.

[0072] The performance of a valve positioner system with a pneumatic output can be improved by individually operating each valve of the valve positioner system with a pneumatic output through corresponding positioner drives.Since there is no steady-state air flow required for the pilot stage, this steady-state air consumption is eliminated.

[0073] It is proposed to use a positioner drive with an integrated magnetic compensator as described above for controlling a valve positioner with a pneumatic output and / or a valve positioner system with a pneumatic output and / or a pneumatic actuator for controlling a process valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principles of the present invention. The accompanying drawings show:

[0075] Figure 1 a shows a prior art valve positioner with a pneumatic output including a return spring;

[0076] Figure 1 b is a force-gap diagram of a valve positioner in the prior art;

[0077] Figure 2a A valve positioner including a force compensator is shown;

[0078] Figure 2b is a force-clearance diagram of a valve positioner including a force compensator;

[0079] Figure 3 a to Figure 3 c, shows a variant of a valve positioner with a positioner drive and a force compensator;

[0080] Figure 4 a. Figure 4 b Magnetic compensator; and the corresponding magnetic force to magnetic gap diagram;

[0081] Figure 5 a to Figure 5 c is a schematic diagram of a variation of the magnetic compensator;

[0082] Figure 6 a to Figure 6 d is a schematic diagram of a variation of a magnetic compensator including a pole face;

[0083] Figure 7 is a schematic diagram of a portion of a magnetic compensator; and

[0084] Figure 8 Valve positioner with positioner actuator and adjustable force compensator. DETAILED DESCRIPTION

[0085] Figure 1 a schematically shows a prior art valve positioner 120 having a pneumatic output mechanically connected to a positioner actuator 100, the positioner actuator 100 being directly mechanically connected to a valve 126 of the valve positioner 120, wherein the valve positioner is provided with a return spring 110 to close the valve 126 in the event that the positioner actuator 100 is closed and / or in a fault mode.

[0086] A conventional valve positioner 120 with a pneumatic output includes a valve 126 and a valve plunger 125 mechanically coupled to the valve 126, a first valve chamber 123, and a second valve chamber 124. The first valve chamber 123 and the second valve chamber 124 can be pneumatically coupled by the valve 126 and a first sealing diaphragm 121. The first sealing diaphragm 121 seals the first chamber 123 from the outside of the valve positioner 120 with a pneumatic output. The second sealing diaphragm 122 is configured to seal the second chamber 124 of the valve positioner 120 from the outside of the valve positioner 120 with a pneumatic output. The first and second sealing diaphragms 121, 122 are installed in the housing of the valve positioner 120 and are coupled to the valve plunger 220.

[0087] Applications of the valve positioner 120 may require a "fail to close" function of the valve positioner 120 to ensure that the valve 126 of the valve positioner 120 is closed in the event of a failure. This requirement may include functionality of the valve positioner 120 having an actuator coupled to the valve positioner 120 that achieves a defined state for a non-electrical power state; meaning that the valve positioner 120 is closed and sealed, for example, if the electrical power to the actuator is cut off.

[0088] This can be achieved by Figure 1 To operate the valve positioner 120 , the positioner actuator 100 must work against the spring 110 to operate the valve 126 .

[0089] Figure 1 b shows a graph of the force F required to shift the valve 126 of the valve positioner 120 to the open position plotted against the valve clearance of the valve 126 of the valve positioner 120 according to the illustrated prior art valve positioner 120 .

[0090] The force 140 of the return spring 110 is also plotted in the figure relative to the valve clearance. The gradient of the force 140 of the return spring 110 indicates that if mechanically coupled to the valve 126 of the valve positioner 120, the return spring 110 is configured to ensure that the force F of the return spring 110 is high enough to force the valve 126 into the closed and sealed position if, for example, the positioner actuator 100 fails.

[0091] When the valve clearance moves from the open position to the closed position, the stem force 130 required to move the valve 126 of the valve positioner 120 (generated by closing the valve 126) begins with a flatter slope 130a relative to the valve clearance curve. This is because the stem force in the first portion 130a is primarily caused by the stiffness of the flexible seal of the valve positioner 120.

[0092] As the valve clearance begins to close, the force F driving the valve seat into the sealing position increases dramatically, as shown by the steeper second segment 130b of the curve 130. Therefore, the positioner actuator 100 must provide a higher force in this steeper portion 130b.

[0093] As can be clearly seen from the figure, the spring force caused by the return spring 110 is higher than the rod force 130, allowing the return spring 110 to drive the valve 126 into the sealed position. To open and / or maintain the position of the valve 126 of the valve positioner 120, the positioner actuator 100 can be configured to provide a force corresponding to the difference between the force of the return spring 140 and the rod force 130. It should be noted that this figure does not take into account the direction of the force, but rather plots the absolute value of the force. Note that the force of the return spring decreases toward the sealed position of the valve 126, which is the end of the spring-driven motion.

[0094] A rod force must be applied to hold the moving shaft in a given position to maintain a certain valve clearance opening. This force must be provided by the positioner driver 100 .

[0095] Figure 2a Schematically shown is a valve positioner 120 having a pneumatic output, which is controlled by a positioner drive 100 and is mechanically coupled to a force compensator 200 .

[0096] The force compensator 200 is depicted as an ideal force compensator 200 whose force will be just high enough to drive the valve 126 into a sealed position and / or to compensate for the stem force corresponding to the stem force valve clearance relationship 130 so that the force required by the positioner actuator 100 to control the valve positioner 120 can be minimized.

[0097] Figure 2b A diagram is shown in which the Figure 1 The prior art valve positioner 120 shown in graph b plots a stem force F curve 130 required to move the valve 126 of the valve positioner 120 to an open position relative to a valve clearance of the valve 126 of the valve positioner 120 .

[0098] The force curve 140 of the ideal force compensator 200 is also plotted relative to the valve lash. The force of the force compensator 200 relative to the valve lash 240 corresponds to the stem force valve lash relationship 130, so that the force provided by the positioner actuator 100 to control the valve positioner 120 can be minimized.

[0099] Figure 3 a. Figure 3 b and Figure 3c schematically shows a variant of a valve positioner 120 having a directly mechanically coupled positioner drive 100 and a directly mechanically coupled force compensator 200 which is arranged in parallel and mechanically coupled to a plunger 125 which is coupled to a valve of the valve positioner 120 .

[0100] exist Figure 3 In FIG. 1 , the force compensator 200 includes a magnetic component 410 including a permanent magnet that is mechanically coupled to the valve 126 of the valve positioner 120 for at least partially compensating for the stem force required to move the valve 126 of the valve positioner 120. The magnetic component 410 is magnetically coupled to a magnetic mating member 420 via a small magnetic coupling gap, thereby providing a magnetic force coupling relationship to approximate the stem force-valve gap relationship 130 of the valve positioner 120. Thus, the force compensator 200 is mechanically arranged in parallel with the positioner actuator 100.

[0101] Figure 3 b corresponds to Figure 3 a, but here the magnetic member 410 comprising a permanent magnet is fixed, and the magnetic mating member 420 is mechanically coupled to the valve 126 of the valve positioner 120 for at least partially compensating for the stem force required to move the valve 126 of the valve positioner 120. As described above, the magnetic member 410 is magnetically coupled to the magnetic mating member 420 via a small magnetic coupling gap to provide a magnetic force to magnetic gap relationship 240 to approximate the stem force to valve gap relationship 130 of the valve positioner 120.

[0102] In the event that there is a significant weight difference between the magnet assembly 410 and the magnetic coupling member 420, the weight of the magnetic assembly 410 and / or the magnetic coupling member 420 may be considered to be greater than that of the magnetic assembly 410 and / or the magnetic coupling member 420 in combination. Figure 3 a and Figure 3 b Select between the embodiments described.

[0103] Figure 3 c corresponds to Figure 3 a and Figure 3 b, however, the force compensator 200 is configured to form an integral part of the positioner drive system 100 , 200 .

[0104] This can result in a compact packaging of the positioner drive system.

[0105] Figure 4Figure a schematically illustrates a half-section of a magnetic compensator 200, including a magnetic component 410 and a magnetic matching element 420. The structures of the magnetic component 410 and the magnetic matching element 420 are rotationally symmetric about the z-axis, which is indicated by a dashed line. The permanent magnet 430 of the magnetic component 410 is magnetized parallel to the z-axis and is partially surrounded by the yoke 412 at two locations, excluding the location where the permanent magnet 430 faces the magnetic matching element 420. The magnetic matching element 420 is arranged to be separated by a magnetic gap adjacent to the magnetic component 410, so that the magnetic component 410 and the magnetic matching element 420 are magnetically coupled, thereby generating an attractive magnetic force between the magnetic component 410 and the magnetic matching element 420.

[0106] Such a magnetic compensator 200 can be mechanically coupled directly to a valve of a valve positioner 120 via a magnetic component 410 or a magnetic mating piece 420, for example, by mechanically coupling the magnetic compensator 200 to a plunger 125 of a valve of the valve positioner 120. The magnetic component 410 or the magnetic mating piece 420 can be coupled to the plunger 125 of the valve.

[0107] Figure 4 b shows the Figure 4 a) is a diagram related to the magnetic compensator 200 in which the force F generated by the attractive magnetic force of the magnetic component 410 and the magnetic mating member 420 is plotted relative to the magnetic gap distance between the magnetic component 410 and the magnetic mating member 420.

[0108] The resulting curves 450a, b, and c correspond to different diameters of the permanent magnet 430: a) 4 mm; b) 3 mm; and c) 2 mm, with larger diameters corresponding to steeper curves. For comparison, the force F required to transition the valve 126 of the valve positioner 120 to the open position 460 is plotted relative to the valve clearance x of the valve 126 of the valve positioner 120.

[0109] As shown, by adjusting the diameter of the permanent magnet 430 and by adjusting other structures of the magnetic compensator 200 , such as the height of the permanent magnet, the attraction force F of the magnetic compensator 200 can be adjusted to the desired rod force to move the valve 126 of the valve positioner 120 .

[0110] Figure 5 a. Figure 5 b and Figure 5 c schematically depicts a further half-cross section of the magnetic compensator 200 with respect to a rotationally symmetrical variation of the configuration of the magnetic component 410 , as calculated by finite element simulation, with indicated magnetic flux lines within the yoke 412 and the magnetic partner 420 .

[0111] exist Figure 5In a, the yoke 412 of the magnetic device 410, which serves as an "inner yoke", is formed as a ring that is rotationally symmetrical relative to the z-axis, wherein the yoke 412 is adjacent to the rotationally symmetrical permanent magnet 430 at an internal position and is opposite to the magnetic partner 420 of the permanent magnet 430, wherein the permanent magnet 430 is also formed as a ring relative to the z-axis.

[0112] exist Figure 5 In b, the yoke 412 of the magnetic component 410 is shown, which is formed as an "outer yoke" and is partially formed as a disk that is rotationally symmetric relative to the z-axis, which covers the L-shaped permanent magnet 430 at a position opposite to the magnetic partner 420, and wherein another part of the yoke 412 is adjacent to the outer side of the permanent magnet 430, and the permanent magnet 430 is formed as a ring relative to the z-axis.

[0113] exist Figure 5 c shows the yoke 412 of the magnetic component 410 formed as an “inner and outer yoke” with permanent magnets 430 incorporated at three locations, leaving locations adjacent to the magnetic fitting 420 open, wherein the permanent magnets 430 are formed as a ring relative to the z-axis.

[0114] Adjustment of the attractive force versus magnetic gap distance relationship 450a, b, c is tailored to the desired stem force versus valve gap relationship 130 by adjusting the magnetic compensator corresponding to the changes shown to move the valve 126 of the valve positioner 120 to the closed position.

[0115] Figure 6 a. Figure 6 b. Figure 6 c and Figure 6 d schematically depicts a further modification of the magnetic compensator 200 that further incorporates and configures a pole face 414 for adapting the attractive force generated by the magnetic component 410 and the magnetic mating member 420 to the force required to move the valve 126 of the valve positioner 120 to the closed position.

[0116] All four 2-D cross-sections of the magnetic compensator 200 are rotationally symmetric about the z-axis and include axially magnetized permanent magnets 430 and ferromagnetic material, such as iron, that provides a specific shape, referred to as pole faces 414. The ferromagnetic pole faces 414 are directly adjacent to the permanent magnets 430 and can be used to influence the magnetic force and magnetic gap relationship of the magnetic compensator 200 depending on the desired rod force and valve relationship 130.

[0117] Figure 7 A portion of a magnetic compensator 200 rotationally symmetric about the z-axis is schematically shown, wherein several permanent disk magnets 430 are inserted into holes in a transparently drawn yoke 412 of a magnetic component 410. The drawn magnetic partner 420 is formed as a disk-shaped ferromagnetic component 430.

[0118] Figure 8 The valve positioner 120 and the adjustable magnetic compensator 200 are schematically shown, the valve positioner 120 is directly coupled to the position driver 100 and the adjustable magnetic compensator 200, and the adjustable magnetic compensator 200 is configured to be adjusted by a distance adjustment device 810 to adjust the magnetic gap of the adjustable magnetic compensator 200 between the magnetic component 410 and the magnetic mating part 420.

[0119] Advantageously, the adjustable magnetic compensator 200 can provide compensation for component and material property tolerances, which can change the magnetic force versus magnetic gap relationship of the magnetic compensator 200. Using such an adjustment device 810 allows the magnetic gap to be adjusted during manufacture of the magnetic compensator 200.

[0120] Figure 8 A simple example of such an adjustment device 810 is schematically depicted, wherein the magnetic component 410 is mechanically coupled to the valve 126 of the valve positioner 120. The magnetic mating member 420 may be fixed to the housing of the valve positioner 120, which includes the adjustment device 810. Thus, the magnetic clearance of the magnetic compensator 200 may be adjusted according to the valve clearance of the valve seat of the valve positioner 120.

Claims

1. A valve positioner system comprising: Valve positioner (120); as well as a positioner drive system; wherein the positioner drive system is mechanically coupled to a valve (126) of the valve positioner (120) for controlling the valve positioner (120), A positioner drive system for a control valve positioner (120) includes: electromagnetic actuator (100); The electromagnetic actuator is based on the electromagnetic Lorentz effect or the electromagnetic magnetoresistance effect. A magnetic compensator (200) for at least partially compensating for a closing force required to move a valve (126) of the valve positioner to a closed position, wherein the magnetic compensator comprises: a magnetic component (410) including a permanent magnet (430); and Magnetic fitting (420); wherein the magnetic component (410) and the magnetic matching member (420) are configured to interact with each other to generate an attractive force for at least partially compensating for the closing force; wherein the magnetic fitting member (420) comprises a ferromagnetic material and is configured to interact with the magnetic component (410), wherein the magnetic compensator (200) is mechanically coupled to the valve (126) of the valve positioner (120); wherein the electromagnetic actuator (100) and the magnetic compensator (200) are arranged in parallel with each other and directly coupled to a plunger (125), the plunger being coupled to the valve (126) of the valve positioner (120), and Characterized in that the magnetic component (410) comprises a yoke (412), the yoke (412) being arranged and configured to increase the attraction force and adapt the attraction force-valve movement relationship to the closing force-valve movement relationship, and wherein the magnetic compensator comprises: An adjusting device (810) is configured to adjust the magnetic coupling between the magnetic component (410) and the magnetic matching component (420) so as to adapt the attraction force-valve movement relationship to the closing force-valve movement relationship.

2. The valve positioner system of claim 1, wherein the magnetic component (410) is shaped as a ring.

3. The valve positioner system according to claim 1 or 2, wherein the yoke (412) of the magnetic component (410) is shaped as a ring and / or a disk.

4. The valve positioner system of claim 1 or 2, wherein the magnetic component (410) includes a pole face (414) adjacent to the permanent magnet (430) to adapt the attraction force-to-valve movement relationship to the closing force-to-valve movement relationship.

5. The valve positioner system according to claim 1 or 2, wherein the magnetic component (410) comprises a plurality of permanent magnet units magnetically coupled to the magnetic yoke (412).

6. The valve positioner system according to claim 1 or 2, wherein the magnetic compensator (200) is arranged relative to the valve (126) of the valve positioner (120) and is configured to lock the valve (126) in the event of an operational failure of the electromagnetic actuator (100) for controlling the valve positioner (120); or to open the valve (126) in the event of an operational failure of the electromagnetic actuator (100) for controlling the valve positioner (120). 7 . Use of a valve positioner system according to claim 1 for controlling a process valve with a pneumatic output and / or a pneumatic actuator.

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