JPH0620164Y2 - Automatic pressure controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic pressure control device for adjusting a pressure of a supplied fluid to a preset pressure.

<Prior Art> Conventionally, there is an automatic pressure control device as shown in FIG. As the valve 2 for adjusting the secondary pressure of the fluid, a direct acting type valve such as a gauge type or a top guide type, or a rotary type valve such as a butterfly type or a ball type is used, and the valve 2 is opened. Pneumatic to operate the degree from the outside,
Alternatively, an electric drive unit 4 is provided and the valve opening is adjusted by the drive unit 4 to adjust the fluid pressure. For this pressure adjustment, the secondary pressure of the valve 2 is detected by the pressure sensor 6, and the detected pressure is PI.
It is input to the D controller 8, and the drive unit 4 is controlled based on the detected pressure, the preset set pressure, and the predetermined PID constant to adjust the opening degree of the valve 2 to adjust the pressure of the valve 2. To the set pressure.

<Problems to be solved by the invention> However, in such an automatic pressure control device, in a steady operation state, when the primary pressure or the secondary load of the valve 2 changes, that is, when a disturbance occurs, The secondary pressure, which is the control target, fluctuates, this is detected by the pressure sensor 6, and P
Since the ID controller 8 repeatedly calculates the opening degree of the valve 2 and supplies it to the drive unit 4, it takes a long time to converge the disturbance after it is generated, resulting in poor responsiveness. Further, what is controlled is not the pressure but the opening degree of the valve. Since the pressure control is performed as a result of adjusting the opening degree of the valve, the operation amount and the pressure given to the valve 2 by the drive unit 4 are controlled. However, there is also a problem that the control becomes complicated because it has no linear relationship. Further, the PID controller 8 promptly converges to the changed set pressure when the set pressure is changed, in addition to the rapid convergence when the disturbance occurs in the steady operation state as described above. Must also be controllable. However, the optimum PID constant for converging the occurrence of the disturbance in the steady state is often different from the optimum PID constant for changing the set pressure and quickly converging to the changed set pressure. Control was also complicated from the point. Further, the disturbance in the steady state often occurs frequently, and the drive unit 4 operates to adjust the opening degree of the valve 2 each time the disturbance occurs, so that the drive unit 4 has many operating opportunities, There is also a problem in that the life of the drive unit 4 is short accordingly.

<Means for Solving the Problems> The present invention is intended to solve the above problems, and therefore, a self-regulating valve that self-adjusts the pressure of a supplied fluid to a preset pressure, and When changing the set pressure of the self-regulating valve, the set pressure changing means for changing the set pressure in proportion to the moving amount of the self, the pressure detecting means for detecting the fluid pressure of the self-adjusting valve to be controlled, and the set pressure. The output of the pressure detection means and the set pressure after the change are input, and the PID control constant selected for the value of the fluid pressure of the self-regulating valve to be the set pressure after the change is used. The control unit calculates the input output of the pressure detecting unit and the changed set pressure, and controls the set pressure changing unit according to the calculation result.

<Operation> According to the present invention, since the self-regulating valve self-adjusts the pressure of the fluid supplied to itself, the disturbance in the steady state is converged by the self-regulating valve itself. Further, when changing the set pressure, the control unit controls the set pressure changing means based on the newly set set pressure, the output of the pressure detecting means and the control constant. As a result, the set pressure changing means changes the set pressure of the self-regulating valve, so that the fluid pressure of the self-regulating valve quickly converges to the new set pressure.

<Embodiment> In FIG. 1, 10 is a pressure reducing valve, which is a kind of self-regulating valve, which self-adjusts the secondary pressure to a preset set pressure. The set pressure of the pressure reducing valve 10 is changed by the drive unit 14 which is a set pressure changing means. This drive 14
Is controlled by the PID controller 16, and the PID controller 16 outputs a signal representing the secondary pressure of the pressure reducing valve supplied from the pressure sensor 18 which is the pressure detecting means, a preset PID constant and a preset pressure signal. Based on this, the pressure on the secondary side of the pressure reducing valve 10 is controlled to be the set pressure set in the PID controller 16.

The pressure reducing valve 10 and the drive unit 14 are configured, for example, as shown in FIG. That is, the motor 22 provided in the upper part of the main body 20
The rotation of the speed reducer 24, the adjustment screw 28 through the spline shaft 26
The adjustment screw 28, the male screw 30
Is screwed into the screw portion 32 for fixing in the main body 20, the adjusting screw 28 descends, and the pressure adjusting spring 38 is moved through the ball 34 and the spring bearing 36 which are in contact with the tip of the adjusting screw 28. Compress one end of. This compression causes the diaphragm 42 to pass through the spring bearing 40 provided at the other end of the pressure adjusting spring 38.
Is compressed, the pilot guide 44 is lowered, and the pilot valve 46 is pushed down against the acting force of the coil spring 48. In this state, when the primary pressure fluid, for example, the primary pressure steam is introduced from the inlet 49, a part of the primary pressure steam passes through the first passage 50 and enters the chamber below the pilot valve 46. Pilot through the pilot valve 46, the second passage 52 entered and opened
Enter the room above 54. As a result, the piston 54 descends against the acting force of the coil spring 55 and opens the main valve body 56. Most of the primary pressure steam introduced from the inlet 49 is sent out from the outlet 58 as secondary pressure steam through the opened main valve body 56. A portion of this secondary pressure steam enters the chamber below diaphragm 42 through third passage 60. If the pressure of the secondary pressure steam is higher than the set pressure set by the pressure adjusting spring 38,
The diaphragm 42 is pushed up against the acting force of the coil spring 48, and the opening degree of the pilot valve 46 is reduced. Therefore, the steam pressure applied to the piston 54 is reduced, the opening of the main valve body 56 is reduced by the acting force of the coil spring 55, and the secondary pressure is reduced to maintain the set pressure. On the other hand, when the secondary pressure is lower than the set pressure, the secondary pressure is increased by the operation reverse to the above, and the set pressure is maintained. In this way, in the pressure reducing valve 10, the secondary pressure is self-adjusted to the set pressure that has been set. In this way, the motor 22, reducer 24, spline 26, adjusting screw 2
8, the female screw portion 32, and the ball 34 constitute the driving portion 14, that is, the set pressure changing means, and the remaining portion shown in FIG.
0, that is, a self-regulating valve.

The pressure is set by moving the pressure adjusting screw 28. Moving distance (operation amount) of this pressure adjusting screw 28
Is proportional to the set pressure, and by moving the pressure adjusting screw 28 with the motor 22, it is possible to set the pressure proportional to the operation amount. The motor 22 is controlled by the PID controller 16 which is the control unit shown in FIG. Since the manipulated variable and the set pressure are in a proportional relationship as described above, the control signal given to the motor 22 by the PID controller 16 is proportional to the set pressure. The control performed by the PID controller 16 is the secondary of the pressure reducing valve 10 measured by the pressure sensor 18 as the pressure detecting means provided in the pipe 62 (see FIG. 1) connected to the delivery port 58 shown in FIG. The PID control is performed so that the pressure becomes the set pressure input to the PID controller 16. The PID constant used for this PID control is selected so that the secondary pressure quickly converges to the newly set set pressure when the set pressure is changed during operation.

In the automatic pressure control valve configured as described above, when the secondary pressure fluctuates due to the fluctuation of the primary pressure or the fluctuation of the load in the state where the pressure reducing valve 10 is set to a certain set pressure, the pressure reducing valve operates as described above. The opening degree of the main valve body 56 of the valve 10 is automatically changed to maintain the secondary pressure at the set pressure.

If the set pressure is changed, the PID controller 16
Controls the motor 22 so that the secondary pressure of the pressure reducing valve 10 quickly converges to the newly set set pressure by the newly set set pressure, the secondary pressure input from the pressure sensor 18, and the PID constant. To do.

Although the pressure reducing valve 10 is used as the self-regulating valve in the above embodiment, other self-regulating valves, such as a primary pressure regulating valve, a differential pressure regulating valve, a relief valve, etc., can be used. Further, although the drive unit is an electric type using the motor 22, it may be a pneumatic type. Moreover, although PID control was performed using the PID controller 16, other control such as P control, P
I control may be performed.

<Effect of Device> As described above, according to the device, the self-regulating valve self-adjusts to maintain the pressure at the set pressure with respect to disturbances such as inlet pressure fluctuation and load fluctuation in the steady state. Therefore, it has less pressure fluctuation and better responsiveness than the conventional automatic pressure control valve. Further, as described above, since the self-regulating valve responds to the disturbance in the steady state, the control unit does not need to control the self-regulating valve in the steady state. Therefore,
When the control unit is a PID controller, it is sufficient to set only the optimum PID constants that cause rapid convergence when the set pressure is changed, which simplifies control. In addition, the control unit controls the set pressure of the self-regulating valve, rather than directly controlling the valve opening unlike the conventional PID controller, so that the control proportional to the set pressure to be set. Since only the signal needs to be supplied, simple control is required. Furthermore, since the drive unit operates only when the set pressure is changed, it does not operate frequently and can maintain a long life. If a self-regulating valve having a pilot function is used as in this embodiment, it is possible to use a small drive unit with a small output.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of an automatic pressure control valve according to the present invention, FIG. 2 is a partially omitted vertical sectional view of a pressure reducing valve used in the same embodiment, and FIG. 3 is a schematic view of a conventional automatic pressure control valve. Is. 10 ... Pressure reducing valve (self-regulating valve), 14 ... Drive unit (set pressure changing means), 16 ... PID controller (control unit), 18
...... Pressure sensor (pressure detection means).

Claims (1)

[Scope of utility model registration request] 1. A self-regulating valve for self-adjusting the pressure of a supplied fluid to a preset pressure, and a set pressure changing means for changing the set pressure of the self-adjusting valve in proportion to its own movement amount. The pressure detection means for detecting the fluid pressure of the self-regulating valve to be controlled, the output of the pressure detection means when changing the set pressure and the set pressure after the change are input, and Using the PID control constant selected for the value to be the set pressure after the fluid pressure is promptly changed, the output of the input pressure detection means and the changed set pressure are calculated, and the An automatic pressure control device comprising: a control unit that controls the set pressure changing unit according to a calculation result.