Pressure reduction valve controller

Abstract

To enable accurate arrival time prediction.SOLUTION: A pressure reduction valve controller 200 includes: a changer 221 that operates an electric actuator 120 and executes pressure change for changing a set pressure to a target pressure; a predictor 223 that predicts arrival time required for an actual pressure of a pressure reduction valve 100 to reach the target pressure; and an acquirer 222 that acquires a response parameter related to control response of an actual pressure change with respect to operation of the electric actuator 120 at the time of pressure change. The predictor 223 performs weighing on a plurality of response parameters acquired by the acquirer 222 in a plurality of times of past pressure change according to the height of response parameters and predicts the arrival time from deviation between the target pressure and the actual pressure of the pressure reduction valve 100 based on the plurality of weighed response parameters.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The technology disclosed herein relates to a control device for a pressure reducing valve.

Background Art

[0002] Conventionally, a control device for controlling the set pressure on the secondary side of a pressure reducing valve has been known. For example, Patent Document 1 discloses a control device in which an electric actuator is connected to a pressure adjusting screw for adjusting the set pressure of a pressure reducing valve, and the electric actuator is operated. Specifically, the control device operates the electric actuator to adjust the screwing amount of the pressure adjusting screw and controls the set pressure of the pressure reducing valve.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when changing the set pressure of the pressure reducing valve to the target pressure, as a method of determining whether or not the actual pressure on the secondary side of the pressure reducing valve has reached the target pressure, there is a method of directly checking the actual pressure on the secondary side of the pressure reducing valve. In addition, there is a method of predicting the arrival time until the actual pressure on the secondary side of the pressure reducing valve reaches the target pressure. Specifically, when the predicted arrival time is reached, it is determined that the actual pressure on the secondary side of the pressure reducing valve has reached the target pressure. In such a case, it is desired to accurately predict the arrival time.

[0005] The technology disclosed herein has been made in view of such a point, and the object thereof is to predict an accurate arrival time.

Means for Solving the Problems

[0006] The pressure reducing valve control device disclosed herein is a control device for a pressure reducing valve whose secondary side set pressure can be adjusted by an electric actuator, and includes a changer that executes a pressure change for operating the electric actuator to change the set pressure to a target pressure, a predictor that predicts the arrival time until the actual pressure on the secondary side of the pressure reducing valve reaches the target pressure, and an acquirer that acquires a responsiveness parameter related to the control responsiveness of the change in the actual pressure with respect to the operation of the electric actuator during the pressure change. The predictor weights a plurality of the responsiveness parameters acquired by the acquirer in a plurality of past pressure changes according to the height of the responsiveness parameter, and predicts the arrival time from the deviation between the target pressure and the actual pressure on the secondary side of the pressure reducing valve based on the weighted plurality of the responsiveness parameters.

Advantages of the Invention

[0007] According to the pressure reducing valve control device, the accurate arrival time can be predicted.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a fluid system 300 including a control device 200 for a pressure reducing valve according to an embodiment. Hereinafter, the control device 200 for the pressure reducing valve is simply referred to as the control device 200.

[0010] The fluid system 300 is a system that utilizes a fluid. The fluid is steam in this example. The fluid system 300 includes, in addition to the control device 200, a pressure source 301, a load device 302, a pressure reducing valve 100, and a pressure sensor 303.

[0011] The pressure source 301 and the load device 302 are connected by a fluid line 304. The pressure source 301 is a boiler in this example and generates steam. The load device 302 is a double kettle in this example and heats the contents contained in the load device 302 using the steam generated by the pressure source 301 as a heat source. The steam flows from the pressure source 301 to the load device 302 as shown by the solid-line arrow.

[0012] The pressure reducing valve 100 is disposed in the fluid line 304. The pressure reducing valve 100 reduces the pressure of the steam generated from the pressure source 301 and allows the reduced-pressure steam to flow out to the load device 302. That is, the pressure reducing valve 100 makes the pressure of the secondary-side steam lower than the pressure of the primary-side steam.

[0013] The set pressure on the secondary side of the pressure reducing valve 100 can be adjusted by an electric actuator 120. Specifically, the pressure reducing valve 100 has a valve body 110 and an electric actuator 120. The electric actuator 120 enables adjustment of the set pressure on the secondary side of the pressure reducing valve 100. Specifically, the valve body 110 has a pressure adjustment screw for adjusting the set pressure. The electric actuator 120 is connected to the pressure adjustment screw and adjusts the set pressure by adjusting the screwing amount of the pressure adjustment screw. Hereinafter, the set pressure on the secondary side is simply referred to as the "set pressure".

[0014] The pressure sensor 303 detects the actual pressure on the secondary side of the pressure reducing valve 100. Specifically, the pressure sensor 303 is disposed in the fluid line 304 between the pressure reducing valve 100 and the load device 302. Hereinafter, the actual pressure on the secondary side is simply referred to as the "actual pressure".

[0015] The control device 200 controls the set pressure of the pressure reducing valve 100 via the electric actuator 120. Specifically, the control device 200 outputs an operation signal to the electric actuator 120 to adjust the pressure adjusting screw of the pressure reducing valve 100 and control the set pressure. The control device 200 controls the electric actuator 120 based on the detection value of the pressure sensor 303.

[0016] FIG. 2 is a schematic cross-sectional view of the pressure reducing valve 100. The pressure reducing valve 100 is a pilot-operated pressure reducing valve in this example. The valve body 110 has a first casing 1, a second casing 2, and a third casing 3. The first casing 1, the second casing 2, and the third casing 3 are arranged and connected in order from bottom to top.

[0017] The first casing 1 has an inlet passage 11 and an outlet passage 12. The inlet passage 11 is connected to the fluid line 304 on the pressure source 301 side, and the outlet passage 12 is connected to the fluid line 304 on the load device 302 side.

[0018] Inside the first casing 1, a main valve seat 13 is attached. The main valve seat 13 has a main valve port 13a. The inlet passage 11 and the outlet passage 12 communicate with each other via the main valve port 13a.

[0019] Below the main valve seat 13, a main valve 15 is disposed. The main valve 15 opens and closes the main valve port 13a from below. The main valve 15 is biased in the valve closing direction by a coil spring 16. The lower shaft 15a of the main valve 15 is axially guided by a guide hole 1b in the bottom 1a of the first casing 1.

[0020] A piston 17 is arranged above the main valve 15. The piston 17 slides inside a cylinder 18 attached inside the first casing. The lower surface of the lower shaft 17a of the piston 17 abuts against the upper surface of the main valve 15. The piston 17 has a pressure receiving portion 17b at the upper end of the lower shaft 17a. The pressure receiving portion 17b has a piston chamber 17c opening upward.

[0021] A pilot valve seat 21 is attached inside the second casing 2. The pilot valve seat 21 has a pilot valve chamber 21a and a pilot valve port 21b communicating with the pilot valve chamber 21a.

[0022] A pilot valve 22 is attached to the pilot valve seat 21 so as to be movable in the vertical direction. The pilot valve 22 penetrates the pilot valve seat 21. Specifically, the pilot valve 22 penetrates the pilot valve chamber 21a and the pilot valve port 21b.

[0023] The pilot valve 22 has a pilot valve body 22a. The pilot valve body 22a is located below the pilot valve port 21b and opens and closes the pilot valve port 21b from below. The pilot valve body 22a is biased in the valve closing direction by a coil spring 23. The upper end of the upper shaft 22b of the pilot valve 22 protrudes from the upper part of the pilot valve seat 21.

[0024] A first passage 41 is provided in the first casing 1 and the second casing 2. The first passage 41 communicates the inlet passage 11 and the pilot valve chamber 21a via the pilot valve port 21b. A second passage 42 is provided in the second casing 2. The second passage 42 communicates the pilot valve chamber 21a and the piston chamber 17c. When the pilot valve body 22a opens the pilot valve port 21b, the first passage 41 and the second passage 42 communicate with each other.

[0025] The upper part of the second casing 2 has an upper chamber 20 that opens upward. The upper part of the pilot valve seat 21 is located in the upper chamber 20. A third passage 43 is provided in the first casing 1 and the second casing 2. The third passage 43 communicates the outlet passage 12 with the upper chamber 20. The third casing 3 has an internal space 3a that opens downward and a communication passage 3b that communicates with the internal space 3a. The internal space 3a communicates with the outside air via the communication passage 3b.

[0026] A diaphragm 31 is attached between the upper end of the second casing 2 and the lower end of the third casing 3. The diaphragm 31 is disc-shaped, and the outer peripheral edge of the diaphragm 31 is sandwiched between the upper end of the second casing 2 and the lower end of the third casing 3. In other words, the diaphragm 31 partitions the upper chamber 20 of the second casing 2 and the internal space 3a of the third casing 3.

[0027] A pressure setting spring 32 is disposed in the internal space 3a of the third casing 3. The lower end of the pressure setting spring 32 contacts a diaphragm retainer 33. The diaphragm retainer 33 contacts the upper surface of the diaphragm 31. A relief valve seat 37 is attached to the diaphragm retainer 33. The relief valve seat 37 penetrates the diaphragm 31 and is coupled to the diaphragm retainer 33. The diaphragm retainer 33 and the relief valve seat 37 sandwich the diaphragm 31 and are connected to the diaphragm 31. Thereby, the elastic force of the pressure setting spring 32 acts on the upper surface of the diaphragm 31 via the diaphragm retainer 33.

[0028] The lower surface of the relief valve seat 37 contacts the upper end of the upper shaft 22b of the pilot valve 22. Specifically, the relief valve seat 37 has a relief valve port 37a, and the upper end of the upper shaft 22b of the pilot valve 22 contacts the relief valve seat 37 to close the relief valve port 37a. On the other hand, when the upper end of the upper shaft 22b of the pilot valve 22 is separated from the relief valve seat 37, the upper shaft 22b of the pilot valve 22 opens the relief valve port 37a. That is, the upper shaft 22b of the pilot valve 22 also serves as a relief valve body.

[0029] When the upper end of the upper shaft 22b of the pilot valve 22 is in contact with the relief valve seat 37, when the diaphragm 31 moves up and down, the pilot valve 22 moves up and down following the up and down movement of the diaphragm 31. Thereby, the pilot valve body 22a opens and closes the pilot valve port 21b, and the first passage 41 and the second passage 42 are cut off from communication.

[0030] The lower surface of the diaphragm 31 faces the upper chamber 20 of the second casing 2. Thereby, the secondary side pressure from the third passage 43 communicating with the outlet passage 12 on the secondary side of the main valve port 13a acts on the lower surface of the diaphragm 31.

[0031] A spring seat 34 is arranged at the upper end of the pressure setting spring 32. A pressure adjusting screw 36 is arranged on the upper surface of the spring seat 34 via a steel ball 35. The pressure adjusting screw 36 is screwed into the upper part of the third casing 3 so as to be movable up and down. By moving the pressure adjusting screw 36 downward, the pressure setting spring 32 is compressed.

[0032] The electric actuator 120 is attached to the upper part of the third casing 3. The electric actuator 120 has a support base 121, a motor 122, and a telescopic rod 123. The support base 121 is fixed to the upper part of the third casing 3 and supports the motor 122. The telescopic rod 123 is connected to the output shaft of the motor 122 via a gear and can be telescoped by the rotation of the motor 122. The tip of the telescopic rod 123 is connected to the pressure adjusting screw 36. The telescopic rod 123 rotates and operates the pressure adjusting screw 36 by the telescopic operation. Specifically, when the telescopic rod 123 extends, the pressure adjusting screw 36 moves downward while rotating, and on the other hand, when the telescopic rod 123 contracts, the pressure adjusting screw 36 moves upward while rotating.

[0033] Subsequently, the operation of the pressure reducing valve 100 when the set pressure is changed will be described.

[0034] When increasing the set pressure of the pressure reducing valve 100, the electric actuator 120 rotates to displace the pressure adjustment screw 36 downward. When the rotational movement of the pressure adjustment screw 36 increases the elastic force of the pressure setting spring 32 and displaces the diaphragm 31 downward, the pilot valve 22 is pushed down via the relief valve seat 37, and the pilot valve body 22a opens the pilot valve port 21b, allowing the fluid on the inlet passage 11 side to flow into the piston chamber 17c through the first passage 41, the pilot valve chamber 21a, and the second passage 42. The piston 17 is displaced downward by the fluid flowing into the piston chamber 17c. The downward displacement of the piston 17 separates the main valve 15 from the main valve seat 13 and opens the main valve port 13a, allowing the fluid on the inlet passage 11 side to flow into the outlet passage 12 side.

[0035] Since the outlet passage 12 communicates with the upper chamber 20 below the diaphragm 12 via the third passage 43, the fluid on the outlet passage 12 side flows into the upper chamber 20. The fluid flowing into the upper chamber 20 pushes the diaphragm 31 back upward, and at a position balanced with the elastic force of the pressure setting spring 32, the pilot valve body 22a is pushed up by the coil spring 23 to close the pilot valve port 21b. The fluid in the piston chamber 17c escapes to the outlet passage 12 side through the orifice 17d provided in the pressure receiving portion 17b, causing the piston 17 to be displaced upward. The displacement of the piston 17 causes the main valve 15 to contact the main valve seat 13 and close the main valve port 13a. As a result, the pressure on the outlet passage 12 side increases.

[0036] On the one hand, when reducing the set pressure of the pressure reducing valve 100, the electric actuator 120 rotates the pressure adjustment screw 36 upward. When the rotational movement of the pressure adjustment screw 36 reduces the elastic force of the pressure setting spring 32 and the diaphragm 31 is displaced upward, the upper shaft 22b of the pilot valve 22 also serving as a relief valve body separates from the relief valve seat 37 to open the relief valve port 37a. The fluid on the outlet passage 12 side is discharged to the outside air through the third passage 43, the upper chamber 20, the relief valve port 37a, the internal space 3a, and the communication passage 3b, and the pressure in the upper chamber 20 below the diaphragm 31, that is, the pressure on the outlet passage 12 side, decreases. When the diaphragm 31 is pushed back downward by the elastic force of the pressure setting spring 32 and the elastic force of the pressure setting spring 32 and the pressure on the outlet passage 12 side are balanced, the relief valve port 37a is closed by the upper shaft 22b of the pilot valve 22. As a result, the pressure on the outlet passage 12 side decreases.

[0037] The control device 200 operates the electric actuator 120 to adjust the pressure adjustment screw 36 of the valve body 110 and control the set pressure of the pressure reducing valve 100. Specifically, when the control device 200 receives an input of the target pressure of the set pressure, it obtains the screwing amount of the pressure adjustment screw 36 with respect to the target pressure and transmits an operation signal corresponding to the screwing amount to the electric actuator 120. The electric actuator 120 rotates the pressure adjustment screw 36 based on the operation signal. The spring seat 34 is displaced in the vertical direction, the elastic force of the pressure setting spring 32 is adjusted, and the elastic force acting on the diaphragm 31 is adjusted. In this way, the set pressure of the pressure reducing valve 100 is changed to the target pressure. For example, the target pressure is changed according to the usage status of the load device 302.

[0038] The control device 200 predicts the arrival time until the actual pressure of the pressure reducing valve 100 reaches the target pressure from the deviation between the target pressure and the actual pressure of the pressure reducing valve 100. Specifically, when changing the set pressure to the target pressure, the control device 200 acquires a responsiveness parameter related to the control responsiveness of the change in the actual pressure with respect to the operation of the electric actuator 120, and weights the plurality of responsiveness parameters corresponding to a plurality of past pressure changes according to the height of the responsiveness parameter, and predicts the arrival time based on the weighted plurality of responsiveness parameters.

[0039] The control device 200 stores the relationship between the screwing amount of the pressure adjustment screw 36 and the change amount of the set pressure of the pressure reducing valve 100. For example, the control device 200 detects the screwing amount of the pressure adjustment screw 36 by detecting the rotational position of the output shaft of the motor 122 that rotates the pressure adjustment screw 36 with an encoder.

[0040] FIG. 3 is a diagram showing a schematic hardware configuration of the control device 200. The control device 200 includes a processor 211, a storage device 212, and a memory 213.

[0041] The processor 211 controls the entire control device 200. The processor 211 performs various arithmetic processes. For example, the processor 211 is formed of a processor such as a CPU (Central Processing Unit). The processor 211 may be formed of an MCU (Micro Controller Unit), an MPU (Micro Processor Unit), an FPGA (Field Programmable Gate Array), a PLC (Programmable Logic Controller), a system LSI, or the like.

[0042] The memory 212 stores various programs and various data executed by the processor 211. The memory 212 is formed of a non-volatile memory, an HDD (Hard Disc Drive), an SSD (Solid State Drive), or the like. The various programs enable the control device 200 to realize various functions. The memory 212 stores the relationship between the set pressure of the pressure reducing valve 100 and the screwing amount of the pressure adjusting screw 36. The memory 212 stores the relationship between the change amount of the set pressure of the pressure reducing valve 100 and the screwing amount of the pressure adjusting screw 36. The memory 212 stores an equation for predicting the arrival time of the actual pressure of the pressure reducing valve 100. The memory 212 stores a reference for the responsiveness parameter used for predicting the arrival time and a threshold value for determining whether to readjust the electric actuator when the arrival time is reached.

[0043] The memory 213 temporarily stores data and the like. For example, the memory 213 is formed of a volatile memory.

[0044] FIG. 4 is a block diagram showing the configuration of the control system of the processor 211. The processor 211 realizes various functions by reading a program from the memory 212 into the memory 213 and expanding it. Specifically, the processor 211 functions as a changer 221, an acquirer 222, and a predictor 223. The processor 211 may further function as a corrector 224.

[0045] The changer 221 executes a pressure change that operates the electric actuator 120 to change the set pressure of the pressure reducing valve 100 to the target pressure. Specifically, when the changer 221 receives an input for changing the set pressure of the pressure reducing valve 100 to the target pressure, it obtains the screwing amount of the pressure adjusting screw 36 corresponding to the target pressure from the relationship between the set pressure of the pressure reducing valve 100 and the screwing amount of the pressure adjusting screw 36 stored in the memory 212. Then, the changer 221 transmits an operation signal corresponding to the obtained screwing amount to the electric actuator 120. In this way, the changer 221 changes the set pressure of the pressure reducing valve 100 to the target pressure.

[0046] The acquirer 222 acquires a responsiveness parameter related to the control responsiveness of the change in the actual pressure with respect to the operation of the electric actuator 120 when the pressure is changed. The responsiveness parameter includes the rate of change of the actual pressure. The responsiveness parameter further includes the dead time of the change in the actual pressure with respect to the operation of the electric actuator 120. The acquirer 222 acquires the rate of change of the actual pressure and the dead time from the measured value of the pressure sensor 303 each time the pressure is changed.

[0047] Here, the responsiveness parameter will be described. FIG. 5 is a graph showing the relationship between time and the actual pressure of the pressure reducing valve 100 when the set pressure of the pressure reducing valve 100 is changed to the target pressure. In FIG. 5, the horizontal axis represents time, and the vertical axis represents pressure. The solid-line pressure PV is the actual pressure. The actual pressure is the measured value measured by the pressure sensor 303. The dotted-line pressure SV is the set pressure input to the control device 200.

[0048] FIG. 5 shows the case where the changer 221 executes a pressure change so that the set pressure of the pressure reducing valve 100 rises to the target pressure. Specifically, it is assumed that the set pressure before the change is the pressure Pa immediately before the change. It is also assumed that the actual pressure of the pressure reducing valve 100 substantially coincides with the pressure Pa immediately before the change. As shown by the dotted-line pressure SV, the set pressure of the pressure reducing valve 100 is changed by the changer 221 from the pressure Pa immediately before the change to the target pressure Px greater than the pressure Pa immediately before the change in the time ta. Specifically, the changer 221 outputs an operation signal to the electric actuator 120 to adjust the pressure adjusting screw 36 in the time ta. As shown by the solid-line pressure PV, the actual pressure of the pressure reducing valve 100 gradually rises from the pressure Pa immediately before the change toward the target pressure Px in the time ta.

[0049] The rate of change of the actual pressure is the rate of change of the actual pressure when the actual pressure reaches a predetermined pressure. For example, the predetermined pressure is the pressure before the change of the set pressure, that is, the pressure Pa immediately before the change, plus 63.2% of the deviation between the target pressure Px and the actual pressure. The rate of change of the actual pressure is the slope of the actual pressure with respect to time. Note that when calculating the deviation, the pressure Pa immediately before the change may be used instead of the actual pressure. Here, let the pressure obtained by adding 63.2% of the deviation to the pressure Pa immediately before the change be the first pressure Pc. Then, assuming that the actual pressure reaches the first pressure Pc at time tc, the slope of the tangent line L of the actual pressure PV at time tc corresponds to the rate of change of the actual pressure.

[0050] The idle time is the time until the actual pressure reaches a predetermined pressure. For example, the predetermined pressure is the pressure before the change of the set pressure, that is, the pressure Pa immediately before the change, plus 10% of the deviation between the target pressure Px and the actual pressure. Note that when calculating the deviation, the pressure Pa immediately before the change may be used instead of the actual pressure. Here, let the pressure obtained by adding 10% of the deviation to the pressure Pa immediately before the change be the second pressure Pb. Then, assuming that the actual pressure reaches the second pressure Pb at time tb, the difference between time tb and time ta corresponds to the idle time.

[0051] In this way, the acquirer 222 acquires the rate of change of the actual pressure and the idle time each time the pressure is changed.

[0052] The predictor 223 predicts, based on the responsiveness parameter, the time required for the actual pressure of the pressure reducing valve 100 to reach the target pressure when the pressure is changed. However, the predictor 223 uses the responsiveness parameter at the time of past pressure changes for predicting the arrival time. That is, the predictor 223 predicts the arrival time using the responsiveness parameters at a plurality of past pressure changes without using the responsiveness parameter in the current pressure change. Note that the responsiveness parameter in the current pressure change is used when the predictor 223 makes future predictions.

[0053] Predictor 223 weights a plurality of responsiveness parameters acquired by acquirer 222 in multiple past pressure changes according to the height of the responsiveness parameters, and based on the weighted plurality of responsiveness parameters, predicts the time to reach from the deviation between the target pressure and the actual pressure of pressure reducing valve 100 until the actual pressure of pressure reducing valve 100 reaches the target pressure. Specifically, the responsiveness parameters include a first responsiveness parameter and a second responsiveness parameter. The first responsiveness parameter is a responsiveness parameter to be weighted and includes the rate of change of the actual pressure. The second responsiveness parameter is a responsiveness parameter not to be weighted and includes the idle time.

[0054] Specifically, predictor 223 weights the plurality of first responsiveness parameters such that the higher the first responsiveness parameter, the heavier the weight. Specifically, predictor 223 weights the plurality of rates of change of the actual pressure in the plurality of first responsiveness parameters according to the magnitude of the absolute value of the rate of change of the actual pressure. That is, predictor 223 weights the plurality of rates of change of the actual pressure such that the larger the magnitude of the absolute value of the rate of change of the actual pressure, the heavier the weight.

[0055] For example, predictor 223 obtains a representative value of the rate of change of the actual pressure calculated based on the weighted plurality of rates of change of the actual pressure, and predicts the time to reach based on the rate of change of the actual pressure. The representative value of the rate of change of the actual pressure is, for example, the weighted average of the absolute values of the plurality of rates of change of the actual pressure. Specifically, assuming that the magnitudes of the absolute values of the rates of change of the actual pressure for the past 5 times are, from the largest, a1, a2, a3, a4, a5, and the larger the magnitude of the absolute value of the rate of change of the actual pressure, the weights are 160%, 120%, 100%, 80%, 40%. The weighted average at this time is obtained by (160%×a1 + 120%×a2 + 100%×a3 + 80%×a4 + 40%×a5) / (160% + 120% + 100% + 80% + 40%). Note that the weighting values are not limited to the above values.

[0056] The predictor 223 may predict the arrival time based on the dead time in addition to the change rates of a plurality of weighted actual pressures. Specifically, the predictor 223 may use, for the prediction of the arrival time, only the dead time in the most recent pressure change among the plurality of dead times in the plurality of responsiveness parameters. In other words, the predictor 223 predicts the arrival time based on the representative value of the change rate of the actual pressure and the representative value of the dead time, using the dead time in the most recent pressure change as the representative value of the dead time.

[0057] The arrival time refers to the time T from the time ta shown in FIG. 5. That is, when the arrival time T is reached at the time td, the arrival time T is the difference between the time td and the time ta. The timing of the prediction of the arrival time by the predictor 223 is, for example, the point in time when the changer 221 receives the input of the change to the target pressure of the set pressure of the pressure reducing valve 100. Alternatively, the timing of the prediction of the arrival time by the predictor 223 may be the time ta, or may be any time before reaching the arrival time.

[0058] The predictor 223 may predict the arrival time based on the following formula (1).

[0059] T = Δ × B + A ···(1) Here, T is the arrival time, Δ is the deviation, A is the representative value of the dead time, and B is the representative value of the change rate of the actual pressure calculated based on the change rates of a plurality of weighted actual pressures.

[0060] The arrival time T is the time from the time ta to the time td. The deviation Δ is the ratio of the deviation between the target pressure and the actual pressure of the pressure reducing valve 100 to the maximum value (i.e., full scale) of the measurement range of the pressure sensor 303. The unit of the deviation Δ is [%]. The representative value of the dead time A is the dead time in the most recent pressure change. The unit of the dead time A is [s]. The representative value B of the change rate of the actual pressure is the change rate when the actual pressure is expressed as a ratio [%] to the full scale of the pressure sensor 303. The unit of the representative value B of the change rate of the actual pressure is [% / s]. The representative value B is, for example, the ratio of the weighted average of the absolute values of the change rates of the plurality of actual pressures described above to the full scale of the pressure sensor 303.

[0061] Note that the deviation Δ may be the deviation between the target pressure and the actual pressure of the pressure reducing valve 100. That is, the unit of the deviation Δ may be [MPa]. Further, the representative value B of the change rate of the actual pressure may be the change rate when the actual pressure is expressed as an absolute value [MPa] instead of a ratio. That is, the unit of the representative value B of the change rate of the actual pressure may be [MPa / s].

[0062] The predictor 223 preferably excludes the responsiveness parameters lower than a reference among a plurality of responsiveness parameters from the plurality of responsiveness parameters used for predicting the arrival time. Specifically, the predictor 223 may exclude the change rate of the actual pressure lower than the reference among the change rates of the plurality of actual pressures from the plurality of change rates of the actual pressure used for predicting the arrival time. For example, when obtaining the weighted average of the absolute values of the change rates of the plurality of actual pressures, the predictor 223 does not adopt the change rate of the actual pressure lower than the reference.

[0063] The reference is, for example, that the actual pressure exceeds a predetermined reference pressure. Specifically, when the pressure PV of the solid line shown in FIG. 5 does not finally exceed (for example, after the elapse of the predicted arrival time) a predetermined reference pressure, the change rate of the actual pressure obtained from the pressure PV of the solid line at this time does not satisfy the reference and is excluded from the plurality of change rates of the actual pressure used for predicting the arrival time. The predetermined reference pressure is, for example, the pressure before the change of the set pressure, that is, the pressure Pa immediately before the change, plus 2 / 3 of the deviation between the target pressure Px and the actual pressure. Note that when obtaining the deviation, the pressure Pa immediately before the change may be used instead of the actual pressure.

[0064] The predictor 223 may exclude the idle time lower than a reference among the plurality of idle times from the plurality of idle times used for predicting the arrival time. For example, the predictor 223 uses only the idle time at the most recent pressure change as the most recent pressure change by excluding the pressure change corresponding to the idle time lower than the reference, and uses only the idle time at the most recent pressure change for predicting the arrival time.

[0065] The criterion is, for example, that the actual pressure exceeds a predetermined reference pressure. Specifically, it is the same as the criterion for the change rate of the aforementioned actual pressure. When the pressure PV of the solid line shown in FIG. 5 does not finally exceed the predetermined reference pressure, the waste time obtained from the pressure PV of the solid line at this time is excluded from the plurality of waste times used for predicting the arrival time as not meeting the criterion. The predetermined reference pressure is the same as the predetermined reference pressure for the change rate of the aforementioned actual pressure. For example, it is the pressure obtained by adding 2 / 3 of the deviation between the target pressure Px and the actual pressure to the pressure before the change of the set pressure.

[0066] When predicting, the predictor 223 excludes the responsiveness parameters lower than the criterion from all the responsiveness parameters acquired by the acquirer 222. Incidentally, after acquisition, the acquirer 222 may exclude the responsiveness parameters not meeting the criterion from all the acquired responsiveness parameters.

[0067] When the deviation between the target pressure and the actual pressure when the arrival time is reached is greater than the threshold value, the corrector 224 adjusts the electric actuator 120 so that the actual pressure approaches the target pressure.

[0068] Specifically, as shown in FIG. 5, when the predictor 223 reaches the arrival time T at time td, the corrector 224 obtains the deviation δ between the target pressure Px at time td and the actual pressure at time td. The corrector 224 compares the deviation δ with the threshold value. The threshold value is, for example, a value of 10% of the deviation between the target pressure Px and the actual pressure of the pressure reducing valve 100 (that is, the deviation between the target pressure Px and the pressure Pa immediately before the change). Note that the threshold value is not limited to the above numerical value.

[0069] Then, when the deviation δ is greater than the threshold value, the corrector 224 obtains the screwing amount of the pressure adjustment screw 36 such that the actual pressure of the pressure reducing valve 100 approaches the target pressure. Specifically, the corrector 224 obtains the screwing amount corresponding to the deviation δ from the relationship between the change amount of the set pressure of the pressure reducing valve 100 and the screwing amount of the pressure adjustment screw 36. Then, the corrector 224 transmits an operation signal corresponding to the obtained screwing amount of the pressure adjustment screw 36 to the electric actuator 120 to increase the actual pressure and make it approach the target pressure. On the other hand, when the deviation δ is smaller than the threshold value, the corrector 224 does not output an operation signal for adjustment to the electric actuator 120.

[0070] Here, the case where the deviation δ is greater than the threshold value is, for example, the case where the pressure change is executed in a state with low responsiveness. The pressure change in a state with low responsiveness is, for example, the case where the pressure change is performed in a state where the pressure on the primary side of the pressure reducing valve 100 has decreased. In this case, it is difficult for the actual pressure of the pressure reducing valve 100 to increase. Or, the pressure change in a state with low responsiveness is, for example, the case where a load device such as a double kettle is connected to the secondary side of the pressure reducing valve 100 and the pressure change is performed during the cold start of the load device. In this case, the steam from the pressure reducing valve 100 is used to warm the load device and it is difficult for the actual pressure of the pressure reducing valve 100 to increase. Thus, when the pressure change is executed in a state with low responsiveness, without the correction operation by the corrector 224, it is difficult for the actual pressure to reach the target pressure Px even after the elapse of the arrival time T predicted by the predictor 223.

[0071] Subsequently, the specific processing flow will be described.

[0072] As shown in FIG. 5, when the changer 221 receives the input of the target pressure Px, the changer 221 outputs an operation signal to the electric actuator 120 at time ta to adjust the pressure adjustment screw 36 and executes a pressure change to change the set pressure of the pressure reducing valve 100 to the target pressure Px. Also, the predictor 223 predicts the arrival time T (that is, time td), for example, when the changer 221 receives the input of the target pressure Px. The predictor 223 may output the arrival time T to the display.

[0073] After that, when the arrival time T predicted by the predictor 223 is reached, the corrector 224 determines whether or not the deviation δ between the target pressure and the actual pressure when the arrival time T is reached is greater than the threshold value. In FIG. 5, the corrector 224 determines that the deviation δ is greater than the threshold value, and the corrector 224 adjusts the electric actuator 120 so that the actual pressure approaches the target pressure Px. Thereby, the corrector 224 can increase the actual pressure and make it approach the target pressure Px.

[0074] In this way, the control device 200 can change the actual pressure of the pressure reducing valve 100 to the target pressure Px.

[0075] According to the control device 200 described above, the predictor 223 weights according to the height of the plurality of responsiveness parameters in the plurality of past pressure changes, and predicts the arrival time based on the weighted plurality of responsiveness parameters. Thereby, even if the responsiveness parameter of the immediately preceding pressure change is a responsiveness parameter lower than the reference, the predictor 223 does not predict the arrival time based only on the immediately preceding responsiveness parameter, so that an accurate arrival time can be predicted.

[0076] Specifically, when the predictor 223 predicts the arrival time based only on the responsiveness parameter of the immediately preceding pressure change, if the responsiveness parameter of the immediately preceding pressure change is a responsiveness parameter lower than the reference, the accurate arrival time cannot be predicted. On the other hand, the predictor 223 weights according to the height of the plurality of responsiveness parameters in the plurality of past pressure changes, and predicts the arrival time based on the weighted plurality of responsiveness parameters. Therefore, even if the responsiveness parameter of the immediately preceding pressure change is a responsiveness parameter lower than the reference, the accurate arrival time can be predicted.

[0077] By being able to predict the correct arrival time, it is possible to quickly move on to the next process. For example, if the actual pressure has reached the target pressure at the predicted arrival time, it is possible to move on to the next process. On the other hand, if the actual pressure has not reached the target pressure at the predicted arrival time, an early correction operation can be performed so that the actual pressure approaches the target pressure, and it is possible to quickly move on to the next process. If the arrival time cannot be predicted, it is necessary to wait for a long time until the actual pressure approaches the target pressure, and it is not possible to quickly move on to the next process. In any case, by appropriately predicting the arrival time, it is possible to quickly move on to the next process.

[0078] In addition, the predictor 223 excludes from the plurality of responsiveness parameters those with a responsiveness lower than a reference among the plurality of responsiveness parameters for use in predicting the arrival time. Thereby, the accuracy of the plurality of weighted responsiveness parameters is improved, and a more accurate arrival time can be predicted.

[0079] In addition, the predictor 223 weights the plurality of actual pressure change rates according to the magnitude of the absolute value of the actual pressure change rate, and predicts the arrival time based on the plurality of weighted actual pressure change rates. Thereby, it is possible to easily predict the arrival time based on the actual pressure change rate, which is easy to obtain, among the responsiveness parameters.

[0080] In addition, the predictor 223 predicts the arrival time based on the idle time and the plurality of weighted actual pressure change rates. Thereby, a more accurate arrival time can be predicted.

[0081] In addition, among the plurality of idle times, the predictor 223 uses only the idle time in the most recent pressure change for predicting the arrival time. Thereby, the predictor 223 can use only the idle time in the most recent pressure change for the idle time, and the prediction of the arrival time becomes easy.

[0082] Specifically, the waste time is generally a constant value depending on the type of the pressure reducing valve 100. That is, if the types of the pressure reducing valves 100 are the same, the waste time is generally the same. Therefore, even if the predictor 223 does not perform weighting according to the magnitude of the waste time for the plurality of waste times in the plurality of past pressure changes, the predictor 223 can predict the arrival time using only the waste time in the most recent pressure change.

[0083] In addition, since the predictor 223 predicts the arrival time based on the formula (1), the arrival time can be predicted with a simple formula.

[0084] In addition, since the control device 200 includes the corrector 224, when the actual pressure does not reach the target pressure beyond the arrival time, the corrector 224 can bring the actual pressure closer to the target pressure.

[0085] <<Other Embodiments>> As described above, the above embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited thereto, and is also applicable to embodiments in which changes, replacements, additions, omissions, etc. are appropriately made. In addition, it is also possible to combine the respective components described in the above embodiments to form a new embodiment. Further, among the components described in the accompanying drawings and the detailed description, there may be included not only the components essential for solving the problems, but also the components not essential for solving the problems for the purpose of exemplifying the technology. Therefore, it should not be immediately determined that those non-essential components are essential just because they are described in the accompanying drawings and the detailed description.

[0086] For example, the fluid may be a gas other than vapor, or a liquid such as water or oil. The load device may be an actuator such as an air cylinder. Although the pressure reducing valve 100 is a pilot-operated pressure reducing valve, it may be a direct-acting pressure reducing valve.

[0087] The acquirer 222 acquires the waste time in addition to the change rate of the actual pressure, but may acquire only the change rate of the actual pressure.

[0088] The predictor 223 predicted the arrival time based on the dead time and the change rates of a plurality of weighted actual pressures, but the arrival time may also be predicted based only on the change rates of the plurality of weighted actual pressures.

[0089] Among the plurality of dead times in the plurality of responsiveness parameters, the predictor 223 uses only the dead time in the most recent pressure change for predicting the arrival time, but may also use only the dead time in a non-recent past pressure change among the plurality of dead times for predicting the arrival time.

[0090] The predictor 223 excluded responsiveness parameters lower than a reference from the plurality of responsiveness parameters used for predicting the arrival time, but responsiveness parameters lower than the reference may also be used for predicting the arrival time.

[0091] The predictor 223 predicted the arrival time based on Equation (1), but different relational expressions such as a quadratic function may also be used.

[0092] The control device 200 has a corrector 224, but may not have a corrector 224. For example, when the deviation between the target pressure and the actual pressure when the arrival time is reached is greater than a threshold value, the electric actuator 120 may be manually adjusted so that the actual pressure approaches the target pressure.

[0093] In the above embodiment, the case where the pressure change is executed so that the set pressure of the pressure reducing valve 100 rises to a target pressure higher than the pressure before the change was described, but the pressure change may be executed so that the set pressure of the pressure reducing valve 100 drops to a target pressure lower than the pressure before the change. Note that the pressure before the change may be atmospheric pressure, or may be a pressure different from atmospheric pressure.

[0094] Here, when the set pressure is increased to the target pressure, the actual pressure tends to increase to the target pressure. On the other hand, when the set pressure is decreased to the target pressure, the actual pressure is difficult to decrease to the target pressure. The reason is that the actual pressure is difficult to decrease unless the fluid is consumed on the secondary side of the pressure reducing valve 100. Thus, it takes longer to decrease the actual pressure than to increase the actual pressure.

[0095] The change rate of the actual pressure and the waste time when the set pressure of the pressure reducing valve 100 is decreased to a target pressure lower than the pressure before the change will be described.

[0096] The change rate of the actual pressure is the change rate of the actual pressure when the actual pressure reaches a predetermined pressure. For example, the predetermined pressure is the pressure obtained by subtracting 63.2% of the deviation between the target pressure and the actual pressure from the pressure before the change of the set pressure.

[0097] The waste time is the time until the actual pressure reaches a predetermined pressure. For example, the predetermined pressure is the pressure obtained by subtracting 10% of the deviation between the target pressure and the actual pressure from the pressure before the change of the set pressure.

[0098] The responsiveness parameter related to the control responsiveness may be the rise time, the delay time, the overshoot time, or the settling time.

[0099] Specifically, when the set pressure of the pressure reducing valve 100 is increased to a target pressure higher than the pressure before the change, the rise time is the time until the actual pressure reaches from the pressure before the change of the set pressure to the pressure obtained by adding 10% of the deviation between the target pressure and the actual pressure to the pressure before the change of the set pressure, and then to the pressure obtained by adding 90% of the deviation between the target pressure and the actual pressure to the pressure before the change of the set pressure. Also, the delay time is the time until the actual pressure reaches the pressure obtained by adding 50% of the deviation between the target pressure and the actual pressure to the pressure before the change of the set pressure.

[0100] On the other hand, when the set pressure of the pressure reducing valve 100 drops to a target pressure lower than the pressure before the change, the rise time is the time it takes for the actual pressure to reach the pressure before the change in the set pressure from the pressure obtained by subtracting 10% of the deviation between the target pressure and the actual pressure from the pressure before the change in the set pressure to the pressure obtained by subtracting 90% of the deviation between the target pressure and the actual pressure from the pressure before the change in the set pressure. The delay time is the time it takes for the actual pressure to reach the pressure obtained by subtracting 50% of the deviation between the target pressure and the actual pressure from the pressure before the change in the set pressure.

[0101] The overshoot time is the time it takes for the actual pressure to reach the first peak. The settling time is the time it takes for the actual pressure to fall within the range of ±2% of the deviation between the target pressure and the actual pressure with respect to the target pressure.

[0102] The first responsiveness parameter weighted by the predictor 223 includes the rate of change of the actual pressure, but may also include other responsiveness parameters related to the control responsiveness. The second responsiveness parameter not weighted by the predictor 223 includes the dead time, but may also include other responsiveness parameters related to the control responsiveness.

[0103] The functions realized by the components described in this specification may be implemented in circuitry or processing circuitry including a general-purpose processor, a specific-purpose processor, an integrated circuit, ASICs (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), a conventional circuit, and / or a combination thereof, which are programmed to realize the described functions. The processor includes transistors and other circuits and is regarded as circuitry or processing circuitry. The processor may be a programmed processor that executes a program stored in a memory.

[0104] In this specification, circuitry, units, and means are hardware programmed to implement the described functions or hardware that executes them. The hardware may be any hardware disclosed in this specification or any hardware known to be programmed or execute to implement the described functions.

[0105] When the hardware is a processor regarded as a type of circuitry, the circuitry, means, or unit is a combination of hardware and software used to configure the hardware and / or the processor.

[0106] [Aspect] The above-described embodiments are specific examples of the following aspects.

[0107] (Aspect 1) The control device 200 of the pressure reducing valve is a control device 200 of a pressure reducing valve 100 whose secondary-side set pressure can be adjusted by an electric actuator 120. The control device 200 includes a changer 221 that executes a pressure change to change the set pressure to a target pressure by operating the electric actuator 120, a predictor 223 that predicts the arrival time until the actual pressure on the secondary side of the pressure reducing valve 100 reaches the target pressure, and an acquirer 222 that acquires a responsiveness parameter related to the control responsiveness of the change in the actual pressure with respect to the operation of the electric actuator 120 during the pressure change. The predictor 223 weights the plurality of responsiveness parameters acquired by the acquirer 222 in the plurality of past pressure changes according to the height of the responsiveness parameter, and predicts the arrival time from the deviation between the target pressure and the actual pressure on the secondary side of the pressure reducing valve 100 based on the weighted plurality of responsiveness parameters.

[0108] According to this configuration, the predictor 223 weights a plurality of responsiveness parameters in a plurality of past pressure changes according to the height of the responsiveness parameter, and predicts the arrival time based on the weighted plurality of responsiveness parameters. Thereby, even if the responsiveness parameter of the immediately preceding pressure change is a responsiveness parameter lower than the reference, the predictor 223 does not predict the arrival time based only on the immediately preceding responsiveness parameter, so that an accurate arrival time can be predicted.

[0109] (Aspect 2) In the pressure reducing valve control device 200 according to Aspect 1, The predictor 223 excludes the responsiveness parameter lower than the reference among the plurality of responsiveness parameters from the plurality of responsiveness parameters used for predicting the arrival time.

[0110] According to this configuration, the accuracy of the weighted plurality of responsiveness parameters is improved, and a more accurate arrival time can be predicted.

[0111] (Aspect 3) In the pressure reducing valve control device 200 according to Aspect 1 or Aspect 2, The responsiveness parameter includes a change rate of the actual pressure, The predictor 223 weights a plurality of change rates of the actual pressure in the plurality of responsiveness parameters according to the magnitude of the absolute value of the change rate of the actual pressure, and predicts the arrival time based on the weighted plurality of change rates of the actual pressure.

[0112] According to this configuration, the arrival time can be easily predicted based on the change rate of the actual pressure that is easy to obtain among the responsiveness parameters.

[0113] (Aspect 4) In the pressure reducing valve control device 200 according to any one of Aspects 1 to 3, The responsiveness parameter further includes a dead time of the change of the actual pressure with respect to the operation of the electric actuator 120, The predictor 223 weights the rates of change of the plurality of actual pressures among the plurality of responsiveness parameters according to the magnitude of the absolute value of the rate of change of the actual pressure, and predicts the arrival time based on the dead time and the weighted rates of change of the plurality of actual pressures.

[0114] According to this configuration, the predictor 223 predicts the arrival time based on the dead time in addition to the weighted rates of change of the plurality of actual pressures. Thereby, a more accurate arrival time can be predicted.

[0115] (Aspect 5) In the pressure reducing valve control device 200 according to any one of Aspects 1 to 4, the predictor 223 uses only the dead time in the most recent pressure change among the plurality of dead times in the plurality of responsiveness parameters for predicting the arrival time.

[0116] According to this configuration, the predictor 223 can use only the dead time in the most recent pressure change for the dead time, and it becomes easy to predict the arrival time.

[0117] (Aspect 6) In the pressure reducing valve control device 200 according to any one of Aspects 1 to 5, the predictor 223 predicts the arrival time based on the following formula (1). T = Δ × B + A ··· (1) Here, T is the arrival time, Δ is the deviation, A is the representative value of the dead time, and B is the representative value of the rate of change of the actual pressure calculated based on the weighted rates of change of the plurality of actual pressures.

[0118] According to this configuration, the arrival time can be predicted by a simple formula.

[0119] (Aspect 7) In the pressure reducing valve control device 200 according to any one of Aspects 1 to 6, When the deviation between the target pressure and the actual pressure when the arrival time is reached is greater than the threshold value, a corrector 224 is further provided for adjusting the electric actuator 120 so that the actual pressure approaches the target pressure.

[0120] According to this configuration, since the corrector 224 is provided, when the actual pressure does not reach the target pressure beyond the arrival time, the actual pressure can be brought closer to the target pressure.

Explanation of Signs

[0121] 100 Pressure reducing valve 120 Electric actuator 200 Control device for pressure reducing valve 221 Converter 222 Acquirer 223 Predictor 224 Corrector

Claims

1. A control device for a pressure reducing valve whose set pressure on the secondary side can be adjusted by an electric actuator, comprising: a changer that executes a pressure change for operating the electric actuator to change the set pressure to a target pressure; a predictor that predicts the arrival time until the actual pressure on the secondary side of the pressure reducing valve reaches the target pressure; an acquirer that acquires a responsiveness parameter related to the control responsiveness of the change in the actual pressure with respect to the operation of the electric actuator during the pressure change; The predictor weights a plurality of the responsiveness parameters acquired by the acquirer in a plurality of past pressure changes according to the height of the responsiveness parameter, and based on the weighted plurality of the responsiveness parameters, predicts the arrival time from the deviation between the target pressure and the actual pressure on the secondary side of the pressure reducing valve. A control device for a pressure reducing valve.

2. In the control device for a pressure reducing valve according to Claim 1, the predictor excludes the responsiveness parameter lower than a reference among the plurality of the responsiveness parameters from the plurality of the responsiveness parameters used for predicting the arrival time. A control device for a pressure reducing valve.

3. In the control device for a pressure reducing valve according to Claim 1, the responsiveness parameter includes a change rate of the actual pressure, and the predictor weights a plurality of the change rates of the actual pressure in the plurality of the responsiveness parameters according to the magnitude of the absolute value of the change rate of the actual pressure, and predicts the arrival time based on the weighted plurality of the change rates of the actual pressure. A control device for a pressure reducing valve.

4. In the control device for a pressure reducing valve according to Claim 3, the responsiveness parameter further includes a dead time of the change in the actual pressure with respect to the operation of the electric actuator, and the predictor weights a plurality of the change rates of the actual pressure in the plurality of the responsiveness parameters according to the magnitude of the absolute value of the change rate of the actual pressure, and predicts the arrival time based on the dead time and the weighted plurality of the change rates of the actual pressure. A control device for a pressure reducing valve.

5. In the control device for a pressure reducing valve according to Claim 4, the predictor uses only the dead time in the most recent pressure change among the plurality of the dead times in the plurality of the responsiveness parameters for predicting the arrival time. A control device for a pressure reducing valve.

6. In the control device for a pressure reducing valve according to Claim 4 or 5, the predictor predicts the arrival time based on the following formula (1). A control device for a pressure reducing valve. T = Δ × B + A...(1) Here, T is the arrival time, Δ is the deviation, A is a representative value of the waste time, and B is a representative value of the change rate of the actual pressure calculated based on the change rates of the plurality of weighted actual pressures.

7. In the control device for a pressure reducing valve according to claim 1, a control device for a pressure reducing valve, further comprising a corrector that adjusts the electric actuator so that the actual pressure approaches the target pressure when a deviation between the target pressure and the actual pressure when the arrival time is reached is greater than a threshold value.

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