JP4544614B2 - Positioner device - Google Patents

Description

The present invention relates to electro-pneumatic positioner over to be used in conjunction with pneumatic drive unit for remotely operating a valve.

  The positioner is used in combination with a pneumatic drive unit for remotely controlling a flow rate adjustment valve used in process automation, etc., and follows and stops the drive shaft position of the drive unit at the position indicated by the operation signal. It is a device aimed at. In the flow rate adjustment by the valve having the drive unit using the positioner, in the flow rate adjustment of the fluid, it is important to control the opening degree of the control valve accurately and constantly without being influenced by the pressure or flow rate of the fluid. As such a positioner device, torque is generated in the armature (movable piece) by the magnetic force generated by passing a current through the torque motor, the air pressure supplied to the drive unit is adjusted according to the armature operation, and supplied to the drive unit Electropneumatic positioners that control the opening of a valve by adjusting the air pressure and the amount of air and the follower operation of a drive unit have been widely used in the industry.

  Conventionally proposed mechanical electro-pneumatic positioners use a combination of a feedback lever, a cam, a range adjustment arm, a bearing shaft and a zero adjustment arm as a feedback mechanism between the torque motor and the drive unit. Combining such a mechanical electro-pneumatic positioner and a pneumatic control valve drive unit, the current as an input operation signal is input to a torque motor using an electromagnet to generate a magnetic force, and the movable piece is made minute. Move. As the movable piece moves slightly, the gap between the flapper and the nozzle linked to the movable piece changes, and the gas that has passed through the throttle resistance is converted into nozzle back pressure. The nozzle back pressure is converted into air via the pilot valve mechanism. The drive unit is operated after being converted into air pressure and flow rate for operating the movable unit. The position of the drive shaft is converted to the tension of the feedback spring in the electropneumatic positioner via a feedback lever, cam, etc., and fed back to the moving piece of the torque motor to counteract the magnetic force generated by the input signal. The drive shaft is held at the time when the two are balanced, and the drive shaft is held at a position where the input signal and the position of the drive shaft correspond appropriately.

  In the mechanical electro-pneumatic positioner described above, it is necessary to replace internal components in order to adjust the gain of the overall feedback loop due to the variety of the internal volume of the drive unit pressure chamber and the friction change in the drive unit. The handling is complicated. In addition, torque motors that require fine movement and components around the movable piece have limitations in fine adjustment functions due to nonlinearities due to mechanical deformation and friction, and unexpected zero point movement and dead zone. There was a problem that hysteresis could not be removed. Therefore, an electronic electro-pneumatic positioner using an electronic arithmetic circuit in the feedback loop has been proposed, and an electronic circuit such as a microprocessor is adopted for the feedback function to improve the disadvantages of the mechanical electro-pneumatic positioner.

  In the electronic electro-pneumatic positioner, the drive shaft position of the control valve drive unit that operates with air pressure is converted into an electric signal by a device that converts the position represented by a potentiometer, for example, into an electric signal via a lever and a link mechanism. And led to an electronic circuit that performs comparison operation amplification. The comparison operation amplification circuit compares and calculates the operation signal and the signal related to the drive shaft position, and outputs a current so that the deviation always approaches zero. The electric current is converted into a force by a torque motor using an electromagnet, and is converted into an air pressure output through a nozzle flapper mechanism composed of a nozzle and a flapper and a pilot valve (pressure adjusting unit). Guided to operate the control valve.

  Therefore, in the electronic electro-pneumatic positioner, operational uncertainty due to fluctuations in the operating air pressure, load on the control valve drive or friction, etc. is corrected by the feedback function of the electronic circuit. The control valve drive unit operates and the drive shaft position can be maintained at a predetermined position indicated by the operation signal. In this principle, the input / output relationship between the flapper displacement and the pilot valve output pressure or air flow rate is approximately linear in order for the drive shaft position of the control valve drive unit to operate properly with respect to the operation signal. It is an important premise to be maintained and to respond sufficiently quickly compared to the movement of the control valve drive.

  When the above-mentioned electronic electropneumatic positioner is actually operated, the displacement of the flapper and the air pressure in the nozzle back pressure chamber are not in a strict linear relationship, and the diaphragm that receives the nozzle back pressure of the pilot valve is the diaphragm itself. Has resilience due to elasticity but is weak. Particularly in the vicinity of the operation center point, the restoring force due to elasticity is very weak, and the displacement of the diaphragm cannot maintain linearity with respect to the change of the nozzle back pressure. That is, due to the magnitude of the back pressure of the nozzle and the force caused by the pressure in the pressure chamber, the diaphragm deforms into a concave or convex shape with a slight pressure difference, and its intermediate position becomes a very unstable and transient state. The diaphragm is deformed into irregularities with a certain displacement width, and backlash or hysteresis is generated.

  This phenomenon occurs when the pilot valve port cannot be positioned properly near the equilibrium point where the finest adjustment function is required, that is, near the point where the supply and exhaust of the pilot valve are switched. It means that it becomes difficult to move excessively to the side and perform delicate adjustment operations. For this reason, an excessive reaction in the air supply or exhaust operation causes the drive unit to overshoot the target position indicated by the operation signal, and the corrective action again acts excessively, so that the reciprocating motion is performed around the target position. Will do. This is an unstable phenomenon called hunting in control engineering. In some cases, such as the flow rate adjustment function of the control valve, the plant operation cannot be performed without fulfilling the purpose of adjustment. In order to avoid overshooting this operation, the prior art uses a method of reducing the amplification of the electronic circuit or a drive unit operation by inserting a resistor such as a throttle between the output air pressure and the drive unit to suppress the flow of air. A method of controlling speed was used. However, as a result, the accuracy of the feedback function is reduced, resulting in a dead zone that stops before the position of the drive shaft reaches the target value, and the operation speed of the drive unit is significantly reduced, resulting in slow operation. The problem of becoming.

  FIG. 6 is a graph showing the correlation between the change in the nozzle back pressure and the movement of the diaphragm of the pilot valve, the horizontal axis shows the time change, and the vertical axis shows the displacement amount of the nozzle back pressure and the displacement amount of the diaphragm, respectively. ing. As described above, it can be seen that the displacement of the diaphragm occurs with a time lag from the time when the nozzle back pressure has passed the center position. FIG. 7 is a graph showing the magnitude of the force applied to the diaphragm by the nozzle back pressure and the amount of displacement of the diaphragm. The horizontal axis shows the magnitude of the force applied to the diaphragm, and the vertical axis shows the amount of displacement of the diaphragm. Yes. Since the amount of diaphragm displacement changes abruptly from the moment when the force applied to the diaphragm by the nozzle back pressure and the pressure in the pressure chamber are balanced, there is hysteresis in the amount of diaphragm displacement between the direction in which the nozzle back pressure increases and the direction in which the nozzle back pressure decreases. It can be seen that has occurred. In the above description with reference to FIG. 6, the operation is described in a simplified manner, but the actual operation includes more uncertain elements and performs a more complicated operation.

  This problem is caused not only by the single-acting drive unit in which the drive shaft position is determined according to the drive unit spring and the operating air pressure, but also by the pressure value alone, the drive shaft position is not determined by the air pressure difference between the two ends of the piston. In the double-acting drive unit in which the drive shaft position moves, it becomes a more significant problem. In the double-acting drive unit, the piston does not stop unless the air pressures at the two ends of the piston are equal. Therefore, the double shaft drive continues as long as there is a difference in air pressure between the two ends of the piston. Further, as a conventionally proposed mechanical electro-pneumatic positioner, a system has been proposed in which a double-acting cylinder drive unit is used to branch one of the output air pressures and feed back to the torque motor deviation comparison mechanism ( For example, see Patent Document 1).

JP 2003-239910 A

  In order to cope with the above-described problems of backlash or hysteresis, there is a method of performing minor feedback to the torque motor moving part with a weak spring having a rigid position called a stabilizer spring in the position of the diaphragm. In a mechanical positioner that does not have a main feedback function by an electronic circuit and balances the position signal of the control valve drive unit directly with the force of the torque motor by the force of the feedback nozzle, etc., it is an indispensable technique to obtain stable tracking characteristics It had been. However, this mechanism needs to maintain the relative position between the nozzle flapper mechanism unit consisting of the nozzle and flapper and the pilot valve mechanism unit with high accuracy. The degree of freedom of mechanical structural design was limited.

  However, in the technique described in Patent Document 1, a force is added (subtracted) to the main feedback mechanism in order to branch one of the output air pressures and feed back to the input / output comparison mechanism of the torque motor. Therefore, it is necessary to maintain an accurate feedback amount proportional to the output air pressure. Therefore, a structure that avoids air pressure leakage such as a pressure receiving cap having a rubber sealing function, a metal cap, and a piston-shaped pressure receiving mechanism is required. In addition, in order to suppress fluctuations in the feedback force due to air leakage, a great deal of attention is required to improve the seal, such as the application of grease for advanced machining accuracy and leakage prevention, and such accuracy is maintained. It is extremely difficult to perform a feedback function without error in a delicate mechanism that requires

  In addition, when friction that prevents the movement of the movable piece occurs between the nozzle and the cap, the torque motor operation error becomes an error in the function that compares and balances the feedback loop operation signal with the drive shaft position. Above, it is outside the control loop of the feedback loop and cannot be restored by the feedback mechanism, which causes a large error caused by a minute position change. In addition, if a throttle mechanism for adjusting the flow rate is installed upstream of the feedback nozzle to reduce the amount of air leakage, it will have a significant effect on the feedback pressure when air leakage occurs, and this will be corrected. In a mechanical positioner that does not have a high-order feedback function, serious zero drift may occur.

  Further, in the technique described in Patent Document 1, it is described that the use of the feedback nozzle eliminates the need for the stabilizer spring used in the prior art, and changes the positioner parts depending on the type of the combination drive unit. . However, adjustment of the overall gain of the positioner is indispensable for the diversity of specifications such as the internal volume and load of the combination drive unit. Therefore, considerable difficulty is expected to realize the effect that the adjustment of the positioner gain such as the change of the stabilizer spring becomes unnecessary by the installation of the feedback nozzle.

  Also, in an electronic electropneumatic positioner that uses an electronic circuit for feedback, the output air pressure is detected by a small pressure sensor, and the output signal converted into an electrical signal is fed back to a part of the comparison operation amplification circuit, so that the output pressure is reduced. Some have solved the problem by adopting the principle of maintaining linearity with respect to the current of the torque motor. However, there has been a problem that the manufacturing cost increases due to the necessity of a sensor for detecting pressure and its peripheral circuit, and the cost becomes higher than the obtained effect.

Therefore, the present invention can improve the dynamic characteristics so as to follow the operation signal stably and quickly by improving the non-linear characteristics derived from the mechanical structure and the malfunctions due to backlash or hysteresis. an object of the present invention is to provide a positioner equipment.

In order to solve the above problems, a positioner device of the present invention has a pressure adjusting unit that adjusts the pressure of gas output based on a pressure change in a nozzle back pressure chamber, and a movable piece that operates in accordance with an electrical signal. An operation control unit that controls the pressure of the nozzle back pressure chamber according to the contact and separation state of the nozzle extended from the nozzle back pressure chamber and the movable piece, and the gas pressure output from the pressure adjustment unit. A position measurement unit that measures position of the drive unit to obtain position information, an electric signal control unit that controls the electric signal supplied to the operation control unit based on the position information, and an output from the pressure adjustment unit some of gaseous and a feedback nozzle impinging against the movable piece as jets, a double-acting, wherein the pressure adjusting portion outputs two kinds of pressure, comprising two said feedback nozzle A gas corresponding to the two respective pressure and wherein the impinging on both sides of the movable piece as jets.

  By causing a jet flow having a flow velocity corresponding to the output atmospheric pressure to collide with the movable piece from the feedback nozzle branched from the atmospheric pressure output from the pressure adjusting unit, minor feedback by the jet can be applied to the movable piece. Minor feedback due to the jet acts on the movable piece in accordance with the change in the output pressure of the pilot valve mechanism, and thus works in addition to the main feedback function that eliminates the shift in the position change of the drive unit shaft. By the action of minor feedback by this jet flow, it is possible to correct the nonlinear characteristics such as hysteresis and backlash contained in the mechanical elements of the nozzle flapper mechanism and pilot valve mechanism, and to operate the main feedback function as intended. It becomes.

Also, a double-acting pressure adjusting portion outputs two kinds of pressure includes two feedback nozzle, two or gas corresponding to the respective pressure as impinging on both sides of the movable piece as jets . Even when a double-acting type pressure adjusting unit and a double-acting type driving unit are used, it is possible to cause a jet corresponding to two types of atmospheric pressure to collide with the movable piece and to provide feedback by the jet. Furthermore, since the feedback nozzle and the movable piece are arranged at a predetermined interval, even when the movable piece operates to change the distance between the movable piece and the feedback nozzle, the feedback nozzle and the movable piece are added to the movable piece by the collision of the jet flow. The force can be kept substantially constant, and the feedback by the jet can be favorably applied.

  Non-linearity included in the operation of torque motors and pressure regulators, and instability of operation due to time delays can be appropriately improved with a simple structure, and the performance of the positioner device can be improved at a small cost. it can. For example, when the positioner device according to the present invention is combined with an industrial automatic control valve, the valve opening follows the operation signal stably and quickly, and a large plant such as an oil refiner can be operated more rationally. It can be performed.

  Hereinafter, a positioner device to which the present invention is applied and a driving method thereof will be described in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the remote control of an automatic control valve for automatic operation of a plant such as oil refining, for example, the present invention adjusts the valve opening according to an operation signal, for example, according to an operation signal of 4-20 mA, The present invention relates to a positioner device that holds the position of a drive shaft driven by driving at a position corresponding to an operation signal, and a driving method thereof.

In the present invention, in an electronic electropneumatic positioner having a feedback function by an electronic circuit, a part of the output air pressure is jetted as a jet to the nozzle flapper mechanism to have a minor loop feedback function. The feedback function by the jet improves the non-linear characteristics due to the mechanical configuration of the positioner and the malfunctions due to backlash or hysteresis, and improves the operating characteristics of the electropneumatic positioner to follow the operation signal stably and quickly. .
[First embodiment]

  FIG. 1 is a schematic view showing the structure of a positioner device of the present invention. The positioner device has a structure in which a torque motor unit 1, a pressure adjustment unit 2, a drive unit 3, a position measurement mechanism 4, and a comparison operation amplification circuit 5 are combined. The torque motor unit 1 is a device that generates torque required for position control of the drive shaft when current flows. The pressure adjusting unit 2 converts the nozzle back pressure change into a large-capacity air pressure change by changing the interval between the nozzle and the flapper according to the movement of the flapper operated by the torque generated by the torque motor unit 1, and the drive unit 3 is an apparatus for outputting to the apparatus. The drive unit 3 is a device that moves the position of the drive shaft by the air pressure supplied from the pressure adjustment unit 2. The position measuring mechanism 4 is a device that measures the position of the drive shaft when the drive unit 3 moves the position of the drive shaft, and inputs the position information to the comparison operation amplification circuit 5. The comparison operation amplification circuit 5 is an electric circuit that controls the current value supplied to the torque motor unit 1 in accordance with the position information of the drive shaft measured by the position measurement mechanism 4.

  The torque motor unit 1 has a structure in which an electromagnet 11, a nozzle 12 disposed at a central axis position of the electromagnet 11, and a movable piece 13 that is a ferromagnetic rod-shaped member provided in the front portion of the electromagnet 11 are disposed. Have. Both ends of the conductive material wound around the electromagnet 11 are extended to the outside to form a current input terminal. When the current is supplied to the input terminal, the movable piece 13 magnetized by the magnetic force generated in the electromagnet 11. A force is generated between the electromagnet 11 and the electromagnet 11, and the movable piece 13 is moved by a minute amount in the direction of arrow A in the figure or in the opposite direction. Here, an example in which the nozzle 12 is arranged at the center axis position of the electromagnet 11 is shown, but any position can be used as long as the contact / separation state between the nozzle 12 and the movable piece 13 can be changed. It doesn't matter. 1 shows an example in which an electromagnet is used as the torque motor unit 1, an apparatus capable of controlling torque and adjusting displacement by electrical control can be used. For example, a semiconductor element or a piezoelectric element can be used. An element or the like can be used.

  A fulcrum leaf spring 14, which is an L-shaped elastic body, is attached to one end of the movable piece 13, and one side of the fulcrum leaf spring 14 is fixedly attached to the electromagnet 11. Further, a flapper 15 is formed on the nozzle 12 side of the movable piece 13. When torque is applied to the movable piece 13, the fulcrum leaf spring 14 is elastically deformed according to the torque, and the movable piece 13 and the flapper 15 rotate with the fixed position of the fulcrum leaf spring 14 as the rotation center. Further, the nozzle 12 from which the gas supplied from the pressure adjusting unit 2 flows out is in contact with the flapper 15, and the flapper 15 is operated by applying a torque to the movable piece 13, so that the nozzle 12 and the flapper 15 The positional relationship changes, and the amount of gas flowing out from the nozzle 12 changes.

  A bias spring 16 is attached to the movable piece 13, and an elastic force is generated in the bias spring 16 by the rotational movement of the movable piece 13, and a force is applied to the movable piece 13. Further, a feedback nozzle 17 that ejects the gas supplied from the pressure adjusting unit 2 is disposed on the side of the movable piece 13 opposite to the nozzle 12. The tip of the feedback nozzle 17 is not in contact with the movable piece 13 and faces the movable piece 13 with a small distance. For this reason, the flow of air ejected from the feedback nozzle 17 collides with the movable piece 13 as a jet and applies a force that rotates in the direction of the nozzle 12 to the movable piece 13. In the torque motor unit 1, the flow rate of the gas flowing out from the nozzle 12 is changed by the operation of the movable piece 13, and the pressure adjustment in the pressure adjustment unit 2 is performed. Therefore, the torque motor unit 1 functions as an operation control unit. Become.

  The pressure adjusting unit 2 is supplied with a gas having a pressure higher than the atmospheric pressure from the outside through the supply pipe 21, exchanges gas with the drive unit 3 through the output pipe 22, and connects the nozzle pipe 23 to the pressure pipe 2. Gas flows out from the nozzle 12 through the nozzle 12. The pressure adjusting unit 2 is configured such that the relay spool 25 is slidably disposed inside the casing forming the outer shape, and the gas flows through the gas flow path formed inside the casing, thereby maintaining airtightness. The position of the relay spool 25 changes. An exhaust passage 24 is formed in the vicinity of the central axis inside the relay spool 25, and exhaust is performed outside the pressure adjusting unit 2 through the exhaust passage 24. The output pipe 22 not only transmits and receives gas to the drive unit 3, but also partly branches and is connected to the feedback nozzle 17 of the torque motor unit 1 as a branch pipe 22 x. Is also supplying gas.

  A supply pressure chamber 26, a nozzle back pressure chamber 28, and a relay spool pressure chamber 29 are formed inside the housing of the pressure adjusting unit 2, and a valve port 30 is disposed in the supply pressure chamber 26. A supply pipe 21 is connected to the supply pressure chamber 26 and the relay spool pressure chamber 29, and pressurized gas is supplied into the supply pressure chamber 26 and the relay spool pressure chamber 29. The nozzle back pressure chamber 28 is connected to the supply pressure chamber 26 via a fixed throttle 27 and is connected to the nozzle 12 via a pipe. The nozzle back pressure chamber 28 and the relay spool pressure chamber 29 are adjacent to each other with a deformable partition wall therebetween, and the relay is operated according to the pressure difference between the gases introduced into the nozzle back pressure chamber 28 and the relay spool pressure chamber 29. The spool 25 is movable.

  The valve port 30 is arranged so as to be movable according to the position of the relay spool 25, and when the flow path between the supply pressure chamber 26 and the output pipe 22 is closed, the supply pipe 21 and the exhaust flow path 24 are connected. The function of closing the connection between the supply pipe 21 and the exhaust flow path 24 is realized when the connection is opened and the flow path between the supply pressure chamber 26 and the output pipe 22 is open.

  The drive unit 3 is provided with a diaphragm 32 disposed inside the drive unit housing 31, and a drive unit spring 33 that generates a repulsive force in one space inside the drive unit housing 31 partitioned by the diaphragm 32. The other space is formed as a drive unit pressure chamber 34. Gas is supplied to the drive unit pressure chamber 34 from the pressure adjusting unit 2 via the output pipe 22, and the position of the diaphragm 32 is determined by the balance between the force of the drive unit spring 33 and the force of the atmospheric pressure inside the drive unit pressure chamber 34. It is determined. A drive shaft 35 that is a rod-like member is fixedly attached to the diaphragm 32, and the drive shaft 35 moves following the operation of the diaphragm 32.

  The position measurement mechanism 4 is a device that measures the position of the drive shaft 35 when the drive unit 3 moves the position of the drive shaft 35 and inputs the position information to the comparison operation amplification circuit 5. The position information is measured according to the rotation angle by converting the vertical motion of the image into a rotational motion. The comparison operation amplification circuit 5 is an electric circuit that controls the current value supplied to the torque motor unit 1 in accordance with the position information of the drive shaft measured by the position measurement mechanism 4 as described above. This comparison operation amplification circuit 5 has an amplification function or an integral amplification function for a variety of capacity, operating speed, load to be operated by the drive unit, frictional force, etc. of the drive unit 3 combined with the positioner device. It is assumed that calculation parameters such as integral gain can be changed to a higher level on an electronic circuit or software. The comparison operation amplification circuit 5 functions as an electric signal control unit in order to control the current supplied to the electromagnet 11 based on the position information of the drive shaft 35 measured by the position measurement mechanism 4.

  Next, the operation of the positioner device shown in FIG. 1 and the drive shaft positioning mechanism will be described. When a deviation occurs in the position signal with respect to the operation signal and, as a result, the current flowing as an input signal to the torque motor unit 1 of the positioner device decreases, the magnetic force generated in the electromagnet 11 decreases, and the direction of the electromagnet 11 received by the movable piece 13 And the balance between the elastic force of the fulcrum leaf spring 14 and the elastic force of the bias spring 16 changes. As a result, the torque acting on the movable piece 13 increases in the direction of arrow A in the figure with the fulcrum leaf spring 14 as the center. By the movement of the movable piece 13, the flapper 15 also moves in the direction of the arrow A in the figure, and the interval between the flapper 15 and the nozzle 12 is slightly increased.

  When the gap between the flapper 15 and the nozzle 12 increases, the flow rate of the gas flowing out from the nozzle 12 increases, the pressure in the nozzle back pressure chamber 28 decreases, and the pressure balance between the relay spool pressure chamber 29 and the nozzle back pressure chamber 28 increases. Collapses and the relay spool 25 moves to the nozzle back pressure chamber 28 side. At this time, the relay spool 25 abuts on the valve port 30 to close the exhaust flow path 24, and the valve port 30 moves to open the flow path between the supply pressure chamber 26 and the output pipe 22. As a result, the supply pipe 21, the supply pressure chamber 26 and the output pipe 22 communicate with each other, and the pressurized gas is introduced into the drive unit pressure chamber 34 of the drive unit 3.

  When the gas is introduced into the drive unit pressure chamber 34, the diaphragm 32 moves to a position where the repulsive force of the drive unit spring 33 and the atmospheric pressure of the drive unit pressure chamber 34 are balanced. When the diaphragm 32 moves, the drive shaft 35 also moves. At the same time, the operation of the drive shaft 35 is transmitted to the comparison operation amplification circuit 5 as a change in position information by the position measurement mechanism 4, and the comparison operation amplification circuit 5 feedback-controls the current flowing through the electromagnet 11 based on the position information.

  When the position signal deviates from the operation signal, and as a result, the current flowing as an input signal to the torque motor unit 1 of the electropneumatic positioner increases, the magnetic force generated in the electromagnet 11 increases and the electromagnet 11 received by the movable piece 13. The force in the direction increases, and the balance between the elastic force of the fulcrum leaf spring 14 and the elastic force of the bias spring 16 changes. As a result, the torque acting in the direction of arrow A in the figure around the fulcrum leaf spring 14 is reduced. Due to the movement of the movable piece 13, the flapper 15 also moves in the direction opposite to the arrow A direction in the figure, and the interval between the flapper 15 and the nozzle 12 is slightly narrowed. Hereinafter, the pressure adjustment unit 2, the drive unit 3, the position measurement mechanism 4, and the comparison operation amplification circuit 5 perform the reverse operation to the above-described current decrease, and correspond to the amount of change in the input signal current flowing through the torque motor unit 1. Thus, a change in the position of the drive shaft 35 is obtained.

  In the positioner device of the present invention, not only the normal feedback control by the position measuring mechanism 4 and the comparison operational amplification circuit 5 but also a small amount of air flow from the small hole of the feedback nozzle 17 by branching the output pipe 22 of the pressure adjusting unit 2. To form a minor feedback loop. A small amount of gas is ejected from the feedback nozzle 17 branched from the output pipe 22 and collides with the movable piece 13 of the torque motor unit 1. Due to the force obtained by the gas colliding with the movable piece 13, the force applied to the movable piece 13 is the magnetic force by the electromagnet 11, the elastic force of the fulcrum leaf spring 14, the elastic force of the bias spring 16, and the pressure by the air jet. There will be four. The positioner device according to the present invention feeds back an air jet to the torque motor unit 1 to easily reduce the non-linearity such as backlash and hysteresis and stabilize the operation of the positioner device at low cost.

  In the positioner device of the present invention shown in FIG. 1, a feedback nozzle 17 having a small hole is provided at a certain distance toward the movable piece 13 of the torque motor unit 1, and an output pipe 22 from the pressure adjusting unit 2 is provided. A branched gas is ejected, and the jet of this gas collides with the movable piece 13, and the movement of the movable piece 13 and the flapper 15 is constituted by the force generated by the gas jet collision to form a small loop minor feedback. Hereinafter, the minor feedback operation of the small loop by the jet will be described.

  For example, when the current output input to the torque motor unit 1 decreases, if the gap between the nozzle 12 and the flapper 15 increases due to the force of the bias spring 16, the flow rate of the gas flowing out from the nozzle 12 increases and the nozzle back pressure chamber increases. The pressure in the pressure 28 decreases, the pressure balance between the relay spool pressure chamber 29 and the nozzle back pressure chamber 28 is lost, and the relay spool 25 moves to the nozzle back pressure chamber 28 side. At this time, the relay spool 25 abuts on the valve port 30 to close the exhaust flow path 24, and the valve port 30 moves to open the flow path between the supply pressure chamber 26 and the output pipe 22. As a result, the supply pipe 21, the supply pressure chamber 26, and the output pipe 22 communicate with each other, and the pressurized gas is introduced into the drive section pressure chamber 34 of the drive section 3 and the feedback nozzle branched from the output pipe 22. The speed of the jet spouted from 17 increases.

  Then, the force applied to the movable piece 13 in the direction opposite to the arrow A in the figure increases due to the collision of the jet flow ejected from the feedback nozzle 17, and counters the change in the force applied to the movable piece 13 due to the decrease in the magnetic force of the electromagnet 11. Thus, a force acts in the direction in which the pressure in the nozzle back pressure chamber 28 increases. Due to the action of the feedback force by the jet, the movable piece 13 stops at a position where the force of the jet collision from the feedback nozzle 17 and the force applied to the movable piece 13 by the change of the magnetic force of the electromagnet 11 are balanced. Thereby, in the positioner apparatus of this invention, the output change substantially proportional to the change of the magnetic force of the electromagnet 11 can be obtained. That is, the transfer characteristic having the nonlinearity and hysteresis of the operation of the nozzle flapper mechanism constituted by the nozzle 12 and the flapper 15 and the pressure adjusting unit 2 can be made close to linear.

  On the contrary, when the current input to the torque motor unit 1 increases, the reverse of the above-described operation proceeds. With the increase in the magnetic force of the electromagnet 11 and the force of the bias spring 16, the gap between the nozzle 12 and the flapper 15 is narrowed, the flow rate of the gas flowing out from the nozzle 12 is decreased, and the pressure in the nozzle back pressure chamber 28 is increased. The pressure balance between the relay spool pressure chamber 29 and the nozzle back pressure chamber 28 is lost, and the relay spool 25 moves to the relay spool pressure chamber 29 side. At this time, the relay spool 25 is separated from the valve port 30 and the exhaust passage 24 is opened, and the valve port 30 is moved and the passage between the supply pressure chamber 26 and the output pipe 22 is closed. Thereby, the exhaust passage 24 and the output pipe 22 communicate with each other, the pressure of the gas introduced into the drive unit pressure chamber 34 is reduced, and the speed of the jet flow ejected from the feedback nozzle 17 is reduced. Therefore, the force applied to the movable piece 13 due to the jet collision from the feedback nozzle 17 is reduced, and the force given by the increase in the magnetic force is partially pulled back by the force of the bias spring 16, and the change in the output pressure and the magnetic force are caused by the feedback effect. The movable piece 13 stops at a position balanced with the change of.

  In the main feedback by the comparison operation amplification circuit 5, the position of the drive shaft 35 of the drive unit 3 is converted into an electric signal by the position measurement mechanism 4, and compared with the operation signal by the comparison operation amplification circuit 5, and compared with the feedback effect by the jet flow. With a sufficiently large gain, it is fed back to the output air pressure. Usually, the comparison operational amplifier circuit 5 can be provided with an integral amplification function, so that the main loop gain of high gain can be maintained more stably. The main feedback by the comparison operation amplification circuit 5 functions so that the deviation between the operation signal and the signal of the drive shaft 35 position becomes zero, that is, the position of the drive shaft 35 follows the position specified by the operation signal.

  As described above, when the current input to the electromagnet 11 increases, the force applied to the movable piece 13 due to the jet collision from the feedback nozzle 17 also decreases, and when the current input to the electromagnet 11 decreases, the feedback nozzle The force applied to the movable piece 13 by the jet collision from 17 also increases. That is, the jet flow ejected from the feedback nozzle 17 increases or decreases against the operation according to the electric signal of the movable piece 13. The effect of the minor feedback by the jet of the present invention improves the non-linearity such as hysteresis caused by mechanical elements in the pressure adjusting unit 2 such as the nozzle flapper mechanism and the pilot valve mechanism, and the apparent appearance that has occurred as a result. Response delay and distortion of the pilot valve mechanism are improved. As a result, the feedback function expected in the main feedback loop operates normally, and the electronic electropneumatic positioner can perform an ideal following operation while maintaining normal operation.

  Therefore, by using the feedback by the jet according to the present invention, it is possible to eliminate the hysteresis between the nozzle back pressure and the diaphragm displacement shown in FIG. As a result, the operation as a positioner by the main feedback function can be brought close to an ideal following operation.

  As will be described later, the feedback effect by the jet flow of the present invention has a slight effect even if a slight variation in the static characteristics derived from mechanical elements and the uncertainty of the movable piece 13 occur. The position of the drive shaft 35 of the drive unit 3 corresponding to is within a range that can be corrected by the main feedback, and is accurately maintained. Due to the feedback effect of the small loop caused by the jet, the proportionality of the change in the output air pressure from the pressure adjusting unit 2 with respect to the change in the magnetic force applied to the movable piece 13 from the electromagnet 11 is remarkably improved, and the nonlinearity mentioned as a problem In addition, the time delay is remarkably reduced, and the dynamic characteristics of the operation of the positioner can be improved.

  In FIG. 1, the pressure adjusting unit 2 exemplifies a reverse operation type in which the pressure of gas discharged from the output pipe 22 decreases when the pressure in the nozzle back pressure chamber 28 increases. In the case of using a forward operation type in which the pressure of the gas discharged from the output pipe 22 increases when the pressure rises, the position of the feedback nozzle 17 is provided on the opposite side with respect to the movable piece 13, thereby It is possible to obtain an output change substantially proportional to the feedback by the jet flow equivalent to the description and the change of the magnetic force of the electromagnet 11.

  The force applied to the movable piece when the torque motor unit 1 operates is very small, and the flow rate of the jet required to obtain the feedback effect by the jet may be small. Therefore, the diameter of the small hole formed at the tip of the feedback nozzle 17 may be very small, and the flow rate of the gas ejected from the feedback nozzle 17 is extremely small compared to the air processing amount handled inside the pressure adjusting unit 2. For this reason, the influence of the jet flow from the feedback nozzle 17 on the operating pressure of the drive unit 3 is very slight and can be ignored. In view of the fact that conventionally, a technique for providing a small hole in a part of the output pipe 22 in order to stabilize the operation of the pressure adjusting unit 2 and bleeding a small amount of air into the atmosphere is also practically used. It can be said that the influence of the increase in the air throughput required for feedback by the jet is negligible.

  FIG. 2 is a partially enlarged view showing an example of the structure of the feedback nozzle 17 and the movable piece 13 around the feedback nozzle 17 in the positioner device of the present invention. The jet collision part 18 formed at a position facing the feedback nozzle 17 of the movable piece 13 is normally formed in a planar shape, but the jet collision part 18 having a concave surface may be formed. The jet collision unit 18 collides with the jet of gas ejected from the feedback nozzle 17, and the collided jet reverses in the direction of the feedback nozzle 17 along the concave shape of the jet collision unit 18. By making the shape of the surface of the jet collision portion 18 that the jet collides with the concave surface, the direction of the jet flow ejected from the feedback nozzle 17 can be reversed, and the force caused by the jet collision can be increased.

  FIG. 3 shows the distance between the feedback nozzle 17 and the jet collision portion 18 and the force applied to the jet collision portion 18 when the feedback nozzle 17 and the jet collision portion 18 are arranged at a position separated by a minute distance. It is a figure which shows a relationship, and is the figure confirmed by experiment, changing the air pressure by the side of the output piping 22 of the feedback nozzle 17. FIG. FIG. 3A is a cross-sectional view showing the shape of the feedback nozzle 17 used in the experiment, and has a shape in which a hole having a diameter of 1 mm is opened at the tip of a cylindrical tube. FIG. 3B is a cross-sectional view and a plan view showing the shape of the jet impinging portion 18 used in the experiment, and a substantially disk shape and a flat shape are used. FIG. 3C is a graph showing the relationship between the distance between the feedback nozzle 17 and the jet collision part 18 and the force acting on the jet collision part 18. The horizontal axis of FIG. 3C indicates the distance between the feedback nozzle 17 and the jet collision part 18, and the vertical axis indicates the force applied to the jet collision part 18.

  In the experiment, the feedback nozzle 17 and the jet collision unit 18 are opposed to each other, and a constant air pressure is supplied to the feedback nozzle 17, and the distance between the tip of the feedback nozzle 17 and the jet collision unit 18 is changed to The applied force was measured with an electronic load cell. As shown in FIG. 3C, when the atmospheric pressure supplied to the feedback nozzle 17 is about 200 kPa, a force of about 0.90 to 0.10 N is applied to the jet collision portion 18 when the interval is 0.10 mm or more. ing. Further, when the atmospheric pressure supplied to the feedback nozzle 17 is about 400 kPa, a force of about 1.20 to 1.50 N is applied to the jet collision unit 18 when the interval is 0.10 mm or more.

  From FIG. 3 (c), it can be seen that the magnitude of the force applied to the jet impinging portion 18 has a small correlation with the distance between the feedback nozzle 17 and the jet impinging portion 18 and is substantially constant and varies depending on the supplied atmospheric pressure. . Therefore, if the relationship between the diameter of the small hole of the feedback nozzle 17 and the distance of the jet collision part 18 is designed within a predetermined range, the force generated by the collision of the jet depends on the air pressure supplied from the output pipe 22. It can be said that the influence of the variation in distance is relatively small. That is, even when the movable piece 13 is moved by a minute distance due to the operation of the torque motor unit 1 or mechanical fine movement, the force received by the jet collision unit 18 and the movable piece 13 by the jet flow ejected from the feedback nozzle 17 is substantially constant. It is. Further, in the electropneumatic positioner of the present invention, the position of the drive shaft 35 of the drive unit 3 is converted into an electric signal by the position measuring mechanism 4, and compared with the operation signal by the comparison calculation amplification circuit 5, and compared with the feedback effect by the jet flow. With a sufficiently large gain, it is fed back to the output air pressure. Usually, the comparison operational amplifier circuit 5 can be provided with an integral amplification function, so that the main loop gain of high gain can be maintained more stably. The main feedback by the comparison operation amplification circuit 5 functions so that the minor feedback due to the jet has an error due to slight uncertainty, that is, the position of the drive shaft 35 follows the position specified by the operation signal.

  FIG. 4 is a block diagram showing the structure of the positioner device of the present invention described above. The comparison operation amplification circuit 5 supplies current to the torque motor unit 1 based on the operation signal and the position signal, and the nozzle flapper mechanism composed of the nozzle 12 and the flapper 15 is driven by the torque generated by the torque motor unit 1. The The nozzle back pressure of the pressure adjusting unit 2 changes according to the operation of the nozzle flapper mechanism, the valve port 30 moves, the air pressure output from the pressure adjusting unit 2 changes, and the driving unit 3 operates to drive shaft. 35 position changes. In the position measurement mechanism 4, the position of the drive shaft 35 of the drive unit 3 is detected and a position signal is sent to the comparison operation amplification circuit 5. A series of these operations constitutes the main feedback loop of the electronic electropneumatic positioner.

  On the other hand, a part of the air pressure output from the pressure adjusting unit 2 is branched and ejected as a jet flow from the feedback nozzle 17 to act on the nozzle flapper mechanism composed of the nozzle 12 and the flapper 15. The force generated by the jet ejected from the feedback nozzle 17 is fed back to the torque motor unit 1 applied to the flapper 15 to affect the operation of the nozzle flapper mechanism, and the valve port due to the change of the nozzle back pressure in the pressure adjusting unit 2 30 moves and changes in output air pressure. Moreover, the air pressure ejected as a jet flow from the feedback nozzle 17 also changes due to the change in the output air pressure from the pressure adjusting unit 2. The jet flow from the feedback nozzle 17 and a series of operations in the nozzle flapper mechanism and the pressure adjusting unit 2 constitute a minor feedback loop by the jet flow of the present invention.

  The electronic electro-pneumatic positioner of the present invention is composed of a nozzle 12 and a flapper 15 by using a main feedback using the position measuring mechanism 4 and the comparison operation amplification circuit 5 and a minor feedback by a jet flow from the feedback nozzle 17 in combination. The position of the drive shaft 30 in the drive unit 3 is controlled by operating the nozzle flapper mechanism. The minor feedback control by the jet is limited to the nozzle flapper mechanism and the pressure adjustment unit, and can operate with a remarkably short time constant as compared with the main feedback control. As a result, the two feedback loops do not interfere with each other, the minor feedback function corrects the non-linear operating characteristics of the nozzle flapper mechanism and the pressure adjusting unit 2, and the main feedback function accurately determines the position of the drive shaft 35. The electronic electropneumatic positioner can be appropriately operated by following the operation signal.

In the feedback by this jet flow, the pressure change of the gas supplied from the output pipe 22 to the feedback nozzle 17 is converted into the change of the flow velocity, and reconverted into the force due to the collision. Therefore, as compared with the case where the feedback force is transmitted by the pressurizing member in close contact with the movable piece, even if there is some variation in the distance between the movable piece 13 and the feedback nozzle 17, it is less affected. Further, the dimensional accuracy of parts for maintaining the position of the feedback nozzle 17 at a predetermined position of the movable piece 13 is easy, and the processing of the apparatus is simple. In addition, since feedback is performed using a jet unlike the prior art, there is no need for a pressure receiving cap having a rubber seal function, a metal cap, a piston-like pressure receiving mechanism, or the like as a structure that prevents air pressure leakage. In addition, it does not require much attention to improve the seal, such as machining accuracy to suppress fluctuations in feedback force due to air leakage and application of grease to prevent leakage. Therefore, in the positioner device using the feedback by the jet of the present invention and the driving method thereof, a good feedback effect can be obtained with a simple configuration.
[Second Embodiment]

  Next, as another example of the positioner device and the driving method thereof according to the present invention, a double-action positioner device combined with a double-action cylinder drive unit will be described in detail with reference to the drawings. This embodiment uses a double-acting mechanism for the pressure adjustment unit, drives the piston of the drive unit with the differential pressure between the two pressure chambers, and makes the feedback by the jet function on both sides of the movable piece. However, this is different from the first embodiment.

  FIG. 5 is a schematic diagram showing the structure of the positioner device according to the second embodiment. The positioner device has a structure in which a torque motor unit 100, a pressure adjustment unit 200, a drive unit 300, a position measurement mechanism 400, and a comparison operation amplification circuit 500 are combined. The torque motor unit 100 is a device that generates torque necessary for position control of the drive shaft when current flows. The pressure adjustment unit 200 is a device that adjusts the atmospheric pressure supplied to the drive unit 300 according to the torque generated by the torque motor unit 100. The drive unit 300 is a device that moves the position of the drive shaft by the air pressure supplied from the pressure adjustment unit 200. The position measurement mechanism 400 is a device that measures the position of the drive shaft when the drive unit 300 moves the position of the drive shaft, and inputs the position information to the comparison operation amplification circuit 500. The comparison operation amplification circuit 500 is an electric circuit that controls a current value supplied to the torque motor unit 100 according to the position information of the drive shaft measured by the position measurement mechanism 400.

  The torque motor unit 100 has a structure in which an electromagnet 101, a nozzle 102 disposed at the center axis position of the electromagnet 101, and a movable piece 103 which is a ferromagnetic rod-shaped member provided at the front of the electromagnet 101 are disposed. Have. Both ends of the conductive material wound around the electromagnet 101 are extended to the outside to form a current input terminal. When the current is supplied to the input terminal, the movable piece 103 magnetized by the magnetic force generated in the electromagnet 101. A force is generated between the electromagnet 101 and the electromagnet 101, and the movable piece 103 moves by a minute amount in the direction of arrow A in the figure or in the opposite direction. Here, an example is shown in which the nozzle 102 is arranged at the center axis position of the electromagnet 101. However, any position can be used as long as the contact state between the nozzle 102 and the movable piece 103 can be changed. It doesn't matter. FIG. 5 shows an example in which an electromagnet is used as the torque motor unit 1. However, a device capable of controlling torque and adjusting displacement by electrical control can be used. For example, a semiconductor element or a piezoelectric element can be used. An element or the like can be used.

  A fulcrum leaf spring 104, which is an L-shaped elastic body, is attached to one end of the movable piece 103, and one side of the fulcrum leaf spring 104 is fixedly attached to the electromagnet 101. Further, a flapper 105 is formed on the nozzle 102 side of the movable piece 103. When torque is applied to the movable piece 103, the fulcrum leaf spring 104 is elastically deformed according to the torque, and the movable piece 103 and the flapper 105 rotate with the fixed position of the fulcrum leaf spring 104 as the rotation center. The flapper 105 is in contact with the nozzle 102 through which the gas supplied from the pressure adjusting unit 200 flows, and the flapper 105 operates by applying torque to the movable piece 103, so that the nozzle 102 and the flapper 105 The positional relationship changes, and the amount of gas flowing out from the nozzle 102 changes.

  A bias spring 106 is attached to the movable piece 103, and an elastic force is generated in the bias spring 106 by the rotational movement of the movable piece 103, and a force is applied to the movable piece 103. In addition, a feedback nozzle 107 and a feedback nozzle 108 that eject gas supplied from the pressure adjusting unit 200 are disposed on the side of the movable piece 103 opposite to the nozzle 102. The tips of the feedback nozzle 107 and the feedback nozzle 108 are not in contact with the movable piece 103 and are opposed to the movable piece 103 at a minute distance. For this reason, the flow of air ejected from the feedback nozzle 107 and the feedback nozzle 108 collides with the movable piece 103 as a jet and applies a rotating force to each of the movable pieces 103. Although omitted in the drawing, a jet collision part for colliding the jet is formed at a position where the feedback nozzle 107 and the feedback nozzle 108 of the movable piece 103 are opposed to each other. May be added to the movable piece 103. In the torque motor unit 100, the flow rate of the gas flowing out from the nozzle 102 is changed by the operation of the movable piece 103, and the pressure adjustment in the pressure adjustment unit 200 is performed. Therefore, the torque motor unit 100 functions as an operation control unit. Become.

  The pressure adjusting unit 200 is supplied with a gas having a pressure higher than the atmospheric pressure from the outside via the supply pipe 201, and exchanges gas with the drive unit 300 via the output pipe 202a and the output pipe 202b. A gas flows out from the nozzle 102 through the nozzle pipe 203. In the pressure adjusting unit 200, the relay spool 205 is slidably disposed inside the casing forming the outer shape, and the gas flows through the gas flow path formed inside the casing, thereby maintaining airtightness. The position of the relay spool 205 changes. An exhaust passage 204 is formed in the vicinity of the central axis inside the relay spool 205, and exhaust is performed outside the pressure adjustment unit 200 via the exhaust passage 204. The output pipe 202a and the output pipe 202b not only send and receive gas to and from the drive unit 300, but are partially branched to form the branch pipe 202x and the branch pipe 202y, respectively, as the feedback nozzle 107 and the feedback nozzle of the torque motor unit 100. The gas is also supplied to the feedback nozzle 107 and the feedback nozzle 108.

  A supply pressure chamber 206a and a supply pressure chamber 206b are formed inside the casing of the pressure adjusting unit 200 with the relay spool 205 interposed therebetween, and a nozzle back pressure chamber 208 and a relay spool pressure chamber 209 are formed. A valve port 210a is disposed in the pressure chamber 206a, and a valve port 210b is disposed in the supply pressure chamber 206b. A supply pipe 201 is connected to the supply pressure chamber 206a, the supply pressure chamber 206b, and the relay spool pressure chamber 209, and pressurized gas is supplied into the supply pressure chamber 206a, the supply pressure chamber 206b, and the relay spool pressure chamber 209. ing. The nozzle back pressure chamber 208 is connected to the supply pressure chamber 206a via a fixed throttle 207, and is connected to the nozzle 102 via a pipe. The nozzle back pressure chamber 208 and the relay spool pressure chamber 209 are adjacent to each other with a deformable partition wall, and the relay is operated according to the pressure difference between the gas introduced into the nozzle back pressure chamber 208 and the relay spool pressure chamber 209. The spool 205 is movable.

  The valve port 210a is arranged so as to be movable according to the position of the relay spool 205, and when the flow path between the supply pressure chamber 206a and the output pipe 202a is closed, the supply pipe 201 and the exhaust flow path 204 are closed. The function of closing the connection between the supply pipe 201 and the exhaust flow path 204 is realized when the connection is opened and the flow path between the supply pressure chamber 206a and the output pipe 202a is open. The valve port 210b is movably arranged according to the position of the relay spool 205. When the flow path between the supply pressure chamber 206b and the output pipe 202b is closed, the supply pipe 201 and the exhaust flow path 204 are disposed. When the flow path between the supply pressure chamber 206b and the output pipe 202b is open, the function of closing the connection between the supply pipe 201 and the exhaust flow path 204 is realized. Further, the valve port 210a and the valve port 210b are respectively arranged at both ends of the exhaust flow path 204 of the relay spool 205, and when one of the exhaust flow paths 204 is closed, the other is opened. The path 204 is opened and closed.

  In the drive unit 300, a piston 302 disposed inside the drive unit housing 301 is disposed, and one space partitioned by the piston 302 inside the drive unit housing 301 is formed as a drive unit pressure chamber 303, and the other space is formed. Is formed as a drive unit pressure chamber 304. Gas is supplied to the drive unit pressure chamber 303 from the pressure adjustment unit 200 via the output piping 202a, and gas is supplied to the drive unit pressure chamber 304 from the pressure adjustment unit 200 via the output piping 202b. The position of the piston 302 is determined by the balance of the force received by the atmospheric pressure inside the driving unit pressure chamber 303 and the atmospheric pressure inside the driving unit pressure chamber 304. A drive shaft 305 that is a rod-shaped member is fixedly attached to the piston 302, and the drive shaft 305 moves following the operation of the piston 302. In addition, the piston 302 and the drive shaft 305 are slidable by the drive unit housing 301, but a seal member such as an O-ring is disposed between the inner wall of the drive unit housing 301, Gas movement between the drive unit pressure chamber 303 and the drive unit pressure chamber 304 and gas leakage from the drive unit casing 301 are prevented.

  The position measurement mechanism 400 is a device that measures the position of the drive shaft 305 when the drive unit 300 moves the position of the drive shaft 305, and inputs the position information to the comparison operation amplification circuit 500. The position information is measured according to the rotation angle by converting the vertical motion of the image into a rotational motion. The comparison operation amplification circuit 500 is an electric circuit that controls the current value supplied to the torque motor unit 100 in accordance with the deviation between the drive shaft position information and the operation signal measured by the position measurement mechanism 400 as described above. The comparison operation amplification circuit 500 has an amplification function or an integral amplification function with respect to various types such as the capacity of the drive unit 300 combined with the positioner device, the operation speed, the load to be operated by the drive unit, and the frictional force. It is assumed that calculation parameters such as integral gain can be changed to a higher level on an electronic circuit or software. The comparison operation amplification circuit 500 functions as an electric signal control unit in order to control the current supplied to the electromagnet 101 based on the position information of the drive shaft 305 measured by the position measurement mechanism 400.

  Next, the operation of the positioner device shown in FIG. 5 and the drive shaft positioning mechanism will be described. When a deviation occurs in the position signal with respect to the operation signal and, as a result, the current flowing as an input signal to the torque motor unit 100 of the positioner device decreases, the magnetic force generated in the electromagnet 101 decreases, and the electromagnet 101 direction received by the movable piece 103 And the balance between the elastic force of the fulcrum leaf spring 104 and the elastic force of the bias spring 106 changes. As a result, the torque acting on the movable piece 103 increases in the direction of arrow A in the figure around the fulcrum leaf spring 104. Due to the movement of the movable piece 103, the flapper 105 also moves in the direction of the arrow A in the figure, and the interval between the flapper 105 and the nozzle 102 slightly increases.

  When the interval between the flapper 105 and the nozzle 102 is increased, the flow rate of the gas flowing out from the nozzle 102 is increased, the pressure in the nozzle back pressure chamber 208 is decreased, and the pressure balance between the relay spool pressure chamber 209 and the nozzle back pressure chamber 208 is increased. Collapses and the relay spool 205 moves to the nozzle back pressure chamber 208 side. At this time, the relay spool 205 abuts on the valve port 210a to close the space between the exhaust flow path 204 and the valve port 210a, and the valve port 210a moves to open the flow path between the supply pressure chamber 206a and the output pipe 202a. It is. As a result, the supply pipe 201, the supply pressure chamber 206a, and the output pipe 202a communicate with each other, and the pressurized gas is introduced into the drive unit pressure chamber 303 of the drive unit 300.

  At the same time, the valve port 210b moves and the relay spool 205 is separated from the valve port 210b, the space between the exhaust flow path 204 and the valve port 210b is opened, and the flow path between the supply pressure chamber 206b and the output pipe 202b is closed. As a result, the supply pipe 201 and the supply pressure chamber 206b are cut off, the output pipe 202b and the exhaust passage 204 communicate with each other, and the gas in the drive section pressure chamber 304 of the drive section 300 is discharged from the discharge passage and pressure. Decreases.

  As the air pressure in the drive unit pressure chamber 303 increases and the pressure in the drive unit pressure chamber 304 decreases, the piston 302 moves in the direction of arrow C in the figure and continues to move without being balanced. When the comparison operation amplification circuit 500 determines that the signal indicating the position of the drive shaft 305 detected by the position measurement mechanism 400 is equal to the operation signal, the comparison operation amplification circuit 500 changes the output to the electromagnet 101 to change the drive unit pressure chamber 303. Control is performed so that the air pressure and the air pressure in the drive unit pressure chamber 304 are equal.

  Conversely, when the current flowing as an input signal in the torque motor unit 100 of the positioner device increases, the magnetic force generated in the electromagnet 101 increases, the force in the direction of the electromagnet 101 received by the movable piece 103 increases, and the elasticity of the fulcrum leaf spring 104 increases. The balance between the force and the elastic force of the bias spring 106 changes. As a result, the torque acting in the direction of arrow A in the figure around the fulcrum leaf spring 104 is reduced. By the movement of the movable piece 103, the flapper 105 also moves in the direction opposite to the arrow A direction in the drawing, and the interval between the flapper 105 and the nozzle 102 is slightly narrowed. Hereinafter, the pressure adjustment unit 200, the drive unit 300, the position measurement mechanism 400, and the comparison operation amplification circuit 500 perform operations opposite to the above-described current decrease, and correspond to the amount of change in the input signal current flowing through the torque motor unit 100. Thus, a change in the position of the drive shaft 305 is obtained.

  In the positioner device of the present invention, not only the normal feedback control in the position measuring mechanism 400 and the comparison operation amplification circuit 500 but also a small amount of air flow from the small hole of the feedback nozzle 107 by branching the output pipe 202a of the pressure adjusting unit 200. To form a minor feedback loop. Further, a minor feedback loop is formed by branching the output pipe 202b and ejecting a small amount of air flow from the small hole of the feedback nozzle 108 as a jet.

  A small amount of gas is ejected from the feedback nozzle 107 branched from the output pipe 202a and the feedback nozzle 108 branched from the output pipe 202b, and collides with both sides of the movable piece 103 of the torque motor unit 100. Due to the force obtained by the gas colliding with the movable piece 103, the force applied to the movable piece 103 is the magnetic force by the electromagnet 101, the elastic force of the fulcrum leaf spring 104, the elastic force of the bias spring 106, the feedback nozzle 107 and the feedback. There are five pressures due to the air jet from the nozzle 108. The positioner device of the present invention feeds back an air jet to the torque motor unit 100, thereby reducing non-linearities such as backlash and hysteresis easily at low cost and stabilizing the operation of the positioner device.

  In the positioner device of the present invention shown in FIG. 5, the feedback nozzle 107 and the feedback nozzle 108 having small holes are respectively provided on both surfaces of the movable piece 103 of the torque motor unit 100 so as to maintain a certain distance. The output pipe 202a and the output pipe 202b are branched to jet gas, and the jet of gas collides with both sides of the movable piece 103, and the difference in force generated by jet collision of the gas jetted from the two feedback nozzles A force proportional to the difference in pressure applied to both ends of the piston of the double-acting drive unit is fed back to the movement of the movable piece 103 and the flapper 105 to constitute a small loop minor feedback. Hereinafter, the minor feedback operation of the small loop by the jet will be described.

  For example, when the current output input to the torque motor unit 100 decreases, if the gap between the nozzle 102 and the flapper 105 increases due to the force of the bias spring 106, the flow rate of the gas flowing out from the nozzle 102 increases and the nozzle back pressure chamber increases. The pressure in 208 decreases, the pressure balance between the relay spool pressure chamber 209 and the nozzle back pressure chamber 208 is lost, and the relay spool 205 moves to the nozzle back pressure chamber 208 side. At this time, the relay spool 205 comes into contact with the valve port 210a, the valve port 210a side of the exhaust flow path 204 is closed, and the valve port 210a moves to open the flow path between the supply pressure chamber 206a and the output pipe 202a. As a result, the supply pipe 201, the supply pressure chamber 206a, and the output pipe 202a communicate with each other, and the pressurized gas is introduced into the drive section pressure chamber 303 of the drive section 300 and the feedback nozzle branched from the output pipe 202a. The speed of the jet ejected from 107 increases.

  At the same time, the relay spool 205 is separated from the valve port 210b, the valve port 210b side of the exhaust flow path 204 is opened, and the valve port 210b moves to open the flow path between the supply pressure chamber 206b and the output pipe 202b. As a result, the exhaust flow path 204, the supply pressure chamber 206b, and the output pipe 202b communicate with each other and are introduced into the drive unit pressure chamber 304 of the drive unit 300, and jetted from the feedback nozzle 108 branched from the output pipe 202b. Speed decreases.

  Then, the balance between the collision of the jet flow ejected from the feedback nozzle 107 and the collision of the jet flow ejected from the feedback nozzle 108 changes, and the force applied to the movable piece 103 in the direction opposite to the arrow A in the figure increases, and the magnetic force of the electromagnet 101 is increased. The force acts in the direction in which the pressure in the nozzle back pressure chamber 208 rises against the change in the force applied to the movable piece 103 due to the decrease in. Due to the action of the feedback force by the jet flow, the movable piece 103 stops at a position where the force of the jet collision from the feedback nozzle 107 and the feedback nozzle 108 and the force applied to the movable piece 103 due to the change in the magnetic force of the electromagnet 101 are balanced. . Thereby, in the positioner device of the present invention, it is possible to obtain two changes in the output pressure having a pressure difference substantially proportional to the change in the magnetic force of the electromagnet 101. That is, the transfer characteristic having the nonlinearity and hysteresis of the operation of the nozzle flapper mechanism constituted by the nozzle 102 and the flapper 105 and the pressure adjusting unit 200 can be made close to linear.

  On the contrary, when the current input to the torque motor unit 100 increases, the reverse of the above-described operation proceeds. With the increase in the magnetic force of the electromagnet 101 and the force of the bias spring 106, the gap between the nozzle 102 and the flapper 105 becomes narrow, the flow rate of the gas flowing out from the nozzle 102 decreases, and the pressure in the nozzle back pressure chamber 208 increases. The pressure balance between the relay spool pressure chamber 209 and the nozzle back pressure chamber 208 is lost, and the relay spool 205 moves to the relay spool pressure chamber 209 side. At this time, the relay spool 205 is separated from the valve port 210a, the exhaust flow path 204 is opened, and the valve port 210a moves to close the flow path between the supply pressure chamber 206a and the output pipe 202a. As a result, the exhaust flow path 204 and the output pipe 202a communicate with each other, the pressure of the gas introduced into the drive unit pressure chamber 303 is reduced, and the velocity of the jet flow ejected from the feedback nozzle 107 is reduced.

  At the same time, the relay spool 205 comes into contact with the valve port 210b to close the valve port 210b side of the exhaust flow path 204, and the valve port 210b moves to open the flow path between the supply pressure chamber 206b and the output pipe 202b. As a result, the exhaust flow path 204 and the output pipe 202b are shut off, the pressure of the gas supplied to the drive part pressure chamber 304 of the drive part 300 increases, and the gas is ejected from the feedback nozzle 108 branched from the output pipe 202b. The speed of the jet is increased.

  Therefore, the force applied to the movable piece 103 in the direction opposite to the arrow A in the figure due to the jet collision from the feedback nozzle 107 decreases, and the force applied to the movable piece 103 in the direction indicated by the arrow A by the jet collision from the feedback nozzle 108 increases. To do. The force applied to the movable piece 103 includes an increase in the magnetic force of the electromagnet 101, an elastic force of the bias spring 106, a force caused by a jet collision from the feedback nozzle 107, and a force caused by a jet collision from the feedback nozzle 108. Therefore, the change in the magnetic force of the electromagnet 101 is fed back to the movable piece 103 as the flow velocity of the jet flow from the feedback nozzle 107 and the feedback nozzle 108 and is movable at a position where the change in the pressure difference between the two output pressures and the change in the magnetic force are balanced. The piece 103 is stationary.

  As described above, when the current input to the electromagnet 101 increases and the force applied to the movable piece 103 increases in the direction of arrow A in the figure, the movable piece 103 is caused by jet collision from the feedback nozzle 107 and the feedback nozzle 108. The force applied to the arrow increases in the direction of arrow A in the figure. Further, when the current input to the electromagnet 101 decreases and the force applied to the movable piece 103 increases in the direction opposite to the direction of arrow A in the figure, the movable piece 103 is caused by jet collision from the feedback nozzle 107 and the feedback nozzle 108. The force applied to the arrow increases in the direction opposite to the arrow A direction in the figure. That is, the jet flow ejected from the feedback nozzle 107 increases or decreases against the operation according to the electric signal of the movable piece 103.

  By causing a jet flow having a flow velocity corresponding to the output atmospheric pressure to collide with the movable piece from the feedback nozzle branched from the atmospheric pressure output from the pressure adjusting unit, minor feedback by the jet can be applied to the movable piece. Minor feedback due to the jet acts on the movable piece in response to changes in the output pressure of the pilot valve mechanism, so it is added to the main feedback function that eliminates deviations in the position of the drive shaft and operation signals to compensate for its action. . By the action of minor feedback by this jet flow, it is possible to correct the nonlinear characteristics such as hysteresis and backlash contained in the mechanical elements of the nozzle flapper mechanism and pilot valve mechanism, and to operate the main feedback function as intended. It becomes.

  The present embodiment is an example employed in a double-action type positioner device combined with a double-action type drive unit 300, and the feedback nozzle 107 and the feedback nozzle 108 are provided against both surfaces of the movable piece 103. As a result, the jet flow branched from the output of the double-acting pressure adjusting unit 200 receives a force proportional to the differential pressure between the air pressures of the two outputs, with some of the forces caused by the collisions canceling each other out. Therefore, the pressure difference applied to the two ends of the piston 302 of the double-acting drive unit 300 is fed back as a force to the movable piece 103, and the nonlinearity and time delay included in the operation of the torque motor, the pressure adjusting unit, etc. The instability of operability due to the above can be appropriately improved by a simple structure, and the performance of the positioner device can be improved at a small cost. For example, when the positioner device according to the present invention is combined with an industrial automatic control valve, the valve opening follows the operation signal stably and quickly, and a large plant such as an oil refiner can be operated more rationally. It can be performed.

It is a schematic diagram which shows the structure of the single acting type positioner apparatus concerning 1st embodiment of this invention. It is the elements on larger scale which expand and show the feedback nozzle and jet collision part of a positioner device concerning a first embodiment of the present invention. 3A and 3B are views for explaining feedback by jet collision according to the present invention, in which FIG. 3A shows the shape of the feedback nozzle used in the experiment, FIG. 3B shows the shape of the feedback nozzle used in the experiment, and FIG. (C) is a graph which shows the relationship between the distance added to a feedback nozzle and a jet collision part, and the force added to a jet collision part. It is a block diagram which shows the structure and operation | movement of a positioner apparatus of this invention. It is a schematic diagram which shows the structure of the double acting type positioner apparatus concerning 2nd embodiment of this invention. It is a graph which shows the time shift | offset | difference of the nozzle back pressure and the displacement of a diaphragm in the conventional positioner apparatus. It is a graph which shows the hysteresis of the nozzle back pressure in the conventional positioner apparatus, and the displacement of a diaphragm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Torque motor part 2,200 Pressure adjustment part 3,300 Drive part 4,400 Position measuring mechanism 5,500 Comparative calculation amplification circuit 11,101 Electromagnet 12,102 Nozzle 13,103 Movable piece 14,104 Supporting leaf spring 15 , 105 Flapper 16, 106 Bias spring 17, 107, 108 Feedback nozzle 18 Jet impingement part 21, 201 Supply pipe 22, 202a, 202b Output pipe 23, 203 Nozzle pipe 24, 204 Exhaust flow path 25, 205 Relay spools 26, 206a 206b Supply pressure chambers 28, 208 Nozzle back pressure chambers 29, 209 Relay spool pressure chambers 30, 210a, 210b Valve ports 31, 301 Drive unit housing 32 Diaphragm 33 Drive unit springs 34, 303, 304 Drive unit pressure chambers 35, 305 Drive shaft 3 2 piston

Claims (2)

A pressure adjusting unit that adjusts the pressure of the gas output based on the pressure change in the nozzle back pressure chamber;
An operation control unit that has a movable piece that operates in response to an electrical signal, and that controls the pressure of the nozzle back pressure chamber according to the contact state of the movable piece with the nozzle extended from the nozzle back pressure chamber;
A position measuring unit that obtains position information by measuring a state of the driving unit that operates with the pressure of the gas output from the pressure adjusting unit;
An electric signal control unit for controlling the electric signal supplied to the operation control unit based on the position information;
A feedback nozzle that causes a part of the gas output from the pressure adjusting unit to collide against the movable piece as a jet ,
The pressure adjusting unit is a double-acting type that outputs two types of atmospheric pressure, includes two feedback nozzles, and causes gas corresponding to each of the two types of atmospheric pressure to collide with both sides of the movable piece as a jet. A featured positioner device. The positioner device according to claim 1, wherein the feedback nozzle and the movable piece are arranged at a predetermined interval .