JPH0410091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure control valve for adjusting and maintaining the pressure of a fluid from a fluid source at a desired level depending on the purpose of use, and particularly for controlling a motor. This relates to a device in which the pressure is set by driving the.

[Conventional technology]

In general, self-operated pressure reducing valves have a structure in which the valve body opens and closes in conjunction with a diaphragm that is displaced according to the pressure of the secondary fluid, and the lower surface of the diaphragm is exposed to the secondary fluid pressure. The elastic force of the adjustment spring for pressure setting acts downward on the upper surface, and the diaphragm is displaced until these two forces are balanced, and the valve body moves in the valve opening or closing direction. The valve is moved to adjust the amount of fluid passing therethrough, thereby adjusting the secondary fluid pressure to the pressure set by the adjustment spring. This self-powered pressure reducing valve is mechanically controlled by the energy of the fluid to be controlled,
It is simple because it does not require power such as air pressure or electricity, but its adjustment accuracy is lower than that of control valves whose operation is controlled using power such as air pressure or electricity, and therefore it is difficult to obtain high adjustment accuracy. In this case, it is necessary to supplementally control the operation of the self-powered pressure reducing valve using electrical means.

As a pressure reducing valve whose operation is electrically controlled, a motor is attached to the above-mentioned self-powered pressure reducing valve to advance and retreat the adjusting screw for controlling the elastic force of the adjusting spring, and the desired set pressure target value is set to a target value consisting of an upper limit and a lower limit set pressure. A three-position on/off controller compares and determines whether or not the secondary fluid pressure detected by the pressure sensor is within the target range. It is known that a motor is driven by a controller to adjust the elastic force of an adjustment spring, and the motor is stopped when the elastic force of the adjustment spring is within a target range. This type of pressure reducing valve can always maintain the secondary fluid pressure within the target range even if there are slight fluctuations in the primary fluid pressure or flow rate, making it possible to obtain high adjustment accuracy. can. In addition, the motor is stopped when the fluid pressure on the secondary side is within the target range, but even if there is a change in the fluid pressure on the secondary side due to slight load fluctuations, the motor can be used as a self-powered pressure reducing valve as explained at the beginning. Since the secondary fluid pressure is automatically adjusted through proportional operation, the electric actuation control means does not respond too sensitively and the motor frequently rotates forward and reverse, reducing wear on mechanical transmission parts such as gears. Since this does not occur, the product has a very long lifespan, and has the advantage that the original pressure regulating function is not lost even in the event of a power outage. Furthermore, since the connection between the pressure reducing valve and the controller is made by a signal line, the controller can be installed at a location away from the pressure reducing valve, and the target range can be set remotely using a setting device built into the controller or externally attached. Can be set.

[Problem to be solved by the invention]

However, this type of pressure reducing valve has a structure that detects the fluid pressure on the secondary side, drives a motor using a controller, and adjusts the elastic force of the adjustment spring, so it instantly adjusts the pressure when the load fluctuates. It is impossible to do so, and a certain amount of response time is required, which may cause safety-related problems.

For example, in a manufacturing process that repeatedly operates and stops, a cutoff valve may be installed on the primary side of the above-mentioned pressure reducing valve, and the supply of fluid is stopped by the cutoff valve each time one process is completed. When the fluid supply is stopped, the primary fluid pressure becomes 0, and the secondary fluid pressure also becomes 0. Since the secondary fluid pressure is out of the target range, the motor rotates forward according to the controller, but the secondary fluid pressure also becomes 0. Since the fluid pressure on the next side is 0, the motor continues to rotate normally, and when the adjustment screw is screwed in to the maximum, the lower position detection sensor is activated and the motor is stopped. In this state, the elastic force of the adjustment spring is maximum,
Since the set pressure exceeds the required target range, when the shutoff valve is opened at the start of the next process, excessive fluid pressure is temporarily supplied to the secondary side within the response time for pressure adjustment. However, there are drawbacks such as product defects and damage to secondary-side equipment.

In view of these problems, the present invention provides a pressure control valve that prevents the secondary fluid pressure from becoming excessive when the primary fluid is supplied again after the primary fluid pressure becomes 0. With the goal.

[Means to solve the problem]

The pressure control valve according to the present invention is intended to control the secondary side fluid pressure within a target range using a three-position on-off controller that controls the drive of a motor, and the pressure control valve increases the elastic force of the adjustment spring. a timing circuit that outputs a signal when the continuous driving time of the motor has elapsed for a certain period of time; a means for driving the motor in reverse when the fluid pressure on the secondary side is approximately 0 when this signal is output; Means for cutting off the power to the three-position on-off controller when the controller is moved is provided.

Further, a position detection sensor is provided to detect the position of the adjustment screw when the elastic force of the adjustment spring is at its maximum, and when the secondary side fluid pressure is approximately 0 when the detection signal from this position detection sensor is output. The controller may be provided with means for driving the motor in reverse when the adjusting screw moves to the free position, and means for cutting off power to the three-position on-off controller when the adjusting screw moves to the free position.

[Effect]

When the supply of fluid from the primary side is cut off, the fluid pressure on the secondary side becomes smaller than the target range, so the motor is driven and the adjusting screw moves in a direction that increases the elastic force of the adjusting spring. The driving time of the motor is measured by a timing circuit, and if the secondary fluid pressure is approximately 0 when the measured time has elapsed for a certain period of time, the motor is reversed and the motor is moved to the free position where the elastic force of the adjustment spring is 0. When the adjusting screw is retracted, the power to the three-position on-off controller is cut off, the motor and this controller stop, and the pressure control valve closes.

Further, the motor is driven in a direction in which the elastic force of the adjustment spring increases, and the position of the adjustment screw when the elastic force of the adjustment spring is maximum is detected by a position detection sensor, and the secondary fluid pressure at this time is detected. When is approximately 0, the motor reverses, and when the adjusting screw retreats to the free position, the power to the three-position on-off controller is cut off, the motor and this controller stop, and the pressure control valve closes.

〔Example〕

A preferred embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a schematic vertical cross-sectional view of a self-powered pressure reducing valve equipped with electrical operation control means, in which 1 is a conventionally known pressure reducing valve part, 2 is a motor part for operating the adjusting screw of the pressure reducing valve part 1, 3 is a control section that controls the drive of the motor section.

In the pressure reducing valve part 1, 4 is a valve box, and 5 is a valve body spring 7 located on the primary side with respect to the valve seat 6, that is, on the lower side in the figure.
8 is a diaphragm that presses against the valve body 5 via the valve stem 9, and 10 is a diaphragm that controls the pressure of the secondary fluid introduced through the detection hole 10a. 8 is a diaphragm chamber to act on, 11 is a pair of upper and lower spring receivers 12
The adjustment spring 13 is compressed and disposed between the springs a and 12b and applies its elastic force to the diaphragm 8 through the lower spring receiver 12b. This adjustment screw is fitted into the spring receiver 12a, and can be moved back and forth by left and right rotation to adjust the elastic force of the adjustment spring 11. Then, when the fluid is first sent to the primary side,
Initially, the valve body 5 is seated on the valve seat 6 and the opening is closed, but when the adjustment screw 13 is lowered by turning counterclockwise, the elastic force of the adjustment spring 11 increases and the diaphragm 8 is displaced downward, causing the valve The body 5 is pushed open and the primary fluid flows to the secondary side, and this secondary fluid pressure enters the diaphragm chamber 10 through the detection hole 10a, and is combined with the downward pressure of the adjustment spring 11 across the diaphragm 8. The opening degree of the valve body 5 is adjusted so that the upward force of the secondary fluid pressure is balanced, and the secondary fluid pressure is determined.

Next, in the motor section 2, M is the lower reducer 1
5 is a motor that decelerates and transmits its rotation to a gear 15a at the tip of the shaft; 16 is an output shaft that is connected to the ball spline of a gear 17 that meshes with the gear 15a and can rotate and move up and down; 18 is an output shaft 16; This is a shaft joint that connects the lower end of the adjustment screw 13 and the upper end of the adjustment screw 13.The output shaft 16 rotates and moves up and down under the drive of the motor M, and the adjustment screw 13 is rotated via the shaft joint 18, and the adjustment spring The elastic force of 11 can be adjusted. 19 is a position detection disk fixed to the upper side of the output shaft 16, 20a, 20
b is a position detection sensor provided at a position parallel to the output shaft 16, and by detecting the disc 19, the upper and lower limit positions of the vertical movement of the output shaft 16 (at this position, the adjustment spring 11 is When either the upper or lower limit position is detected, a detection signal is sent to the three-position on-off controller (described later), and this controller A stop signal is output in priority over the signal to stop the motor M, and the vertical movement range of the adjustment screw 13 is restricted to prevent mechanical damage to the mechanism part that adjusts the elastic force of the adjustment spring 11. It's summery.

Next, in the control unit 3, 22 is a pressure sensor provided in the secondary side piping to detect the pressure of the secondary side fluid, and 23 is a setting device in which a target range consisting of a desired upper and lower limit set pressure value is set. , 24 is a three-position on/off controller connected to the setting device 23, pressure sensor 22, and position detection sensors 20a, 20b through signal lines, respectively, and is composed of an analog or microcomputer or the like.
The target range set in is compared with the detection value of the pressure sensor 22, and if the detection value is outside the target range, a drive signal is output to the motor M, and if the detection value is within the target range, a stop signal is output. I'm starting to do that. 25 is a drive circuit that controls driving and stopping of the motor M in response to a drive signal or a stop signal from the controller 24; 26 is a timing circuit connected to the controller 24 and the drive circuit 25 by a signal line; Total 24
When a drive signal for forward rotation, that is, screwing in, of the adjusting screw 13 is continuously output for a certain period of time, this is measured and a signal is output to the controller 24. At this time, if the detected value of the secondary side pressure from the pressure sensor 22 is approximately 0, the controller 2
4 outputs a drive signal to reverse the adjustment screw 13, and the adjustment screw 13 is moved to the free position, that is, the adjustment spring 11
After moving the controller to the position where the set pressure is 0,
4 is cut off. still,
The above-mentioned fixed time is, for example, the full stroke time of the adjustment screw 13, that is, the free position of the adjustment screw 13 (the above-mentioned upper limit position) where the set pressure of the adjustment spring 11 is 0 and the elastic force of the adjustment spring 11 is maximum. This refers to the time it takes to move between the above-mentioned lower limit position and the lower limit position. Further, the means for detecting the movement of the adjusting screw 13 to the free position and cutting off the power supply to the controller 24 is, for example, by arranging a sensor at the free position of the adjusting screw 13, and detecting the movement.
A stop signal may be output, or a clock circuit 26 may measure the full stroke time of the adjusting screw 13 during reverse rotation and output a signal to the controller 24.

The present embodiment is constructed as described above, and its operation will now be explained based on the flowchart shown in FIG.

First, the position of the adjusting screw 13 is controlled so that the elastic force of the adjusting spring 11 and the secondary fluid pressure are balanced so that the secondary fluid pressure value is set within the target range set by the setting device 23. When the supply of fluid is stopped by the operation of a cutoff valve (not shown) in the state where the fluid is in the correct state, the fluid pressures on the primary side and the secondary side become zero.
Then, the secondary fluid pressure value deviates from the target range (step 101), so a drive signal is output from the controller 24, and the timing circuit 26 starts measurement (step 102), and the motor M rotates forward (step 101).
103) Then, the adjusting screw 13 is screwed downward, and the elastic force of the adjusting spring 11 increases. Still, the secondary fluid pressure is outside the target range (step 104), so the adjusting screw 13 is screwed further downward, and reaches the lower limit position before the full stroke time elapses, and at this lower limit position, the lower limit position is reached. Detection sensor 2
0b detects the disc 19, and the controller 24 forcibly stops the motor M. However, due to the difference between the target range and the detected value of the pressure sensor 22, the drive signal is still output continuously (steps 103 to 105), and when the measured time elapses over the full stroke time (step 105), the drive signal is output from the clock circuit 26. A signal is sent to the controller 24, and if the detected value of the pressure sensor 22 is approximately 0 (step
106), a drive signal for reversing the motor M is output from the controller 24 (step 107), and the adjusting screw 13 is raised to the free position where the set pressure of the adjusting spring 11 becomes 0, and then sent to the controller 24. energization is cut off, and the controller 24 stops together with the motor M (step 108). In this state, the valve body 5 of the pressure reducing valve part 1
is closed, and even if the shutoff valve is opened in the next step, fluid will not flow to the secondary side. When the controller 24 is energized, a drive signal is sent to the drive circuit 25 of the motor M, and the secondary fluid pressure is adjusted to a preset target range.

As described above, according to this embodiment, when fluid is supplied to the primary side again after the primary fluid pressure becomes 0, it is possible to prevent excessive fluid pressure from being supplied to the secondary side. .

Next, a second embodiment of the present invention will be described based on FIGS. 3 and 4.

FIG. 3 is a schematic vertical cross-sectional view of a self-powered pressure reducing valve similar to FIG. 1, but without the timing circuit 26. In this embodiment, when the adjusting screw 13 descends to the lower limit position and the elastic force of the adjusting spring 11 becomes maximum, and a detection signal is output from the lower position detection sensor 20b that detects this lower limit position, the pressure is increased. When the detected value of the sensor 22 is approximately 0, the program causes the controller 24 to drive the motor M in reverse to move the adjusting screw 13 to the free position.
incorporated into.

Below, explanation will be given with reference to the flowchart of FIG. 4. When the fluid supply is stopped by the operation of the shutoff valve in a state where the elastic force of the adjustment spring 11 and the fluid pressure on the secondary side are balanced, the secondary side When the pressure is out of the target range (step 201), the drive signal output from the controller 24 causes the motor M to rotate forward (step 202), and the adjustment screw 13 is screwed downward, so that the elastic force of the adjustment spring 11 reaches its maximum. Move to the lower limit position. Then, at that position, it is detected by the lower position detection sensor 20b (step 204), and a detection signal is sent to the controller 24, but at the same time, the pressure sensor 22
If the detected value is 0 (step 205), the motor is driven in reverse (step 206), and the adjusting screw 13
In the free position, the power to the controller 24 is cut off,
Motor M and controller 24 stop (step
207).

Although each of the above embodiments has been described using a self-acting direct-acting pressure reducing valve, the present invention is not limited thereto, and may be applied to pressure regulating valves such as pilot operated pressure reducing valves, differential pressure valves, back pressure valves, etc. It can also be applied to temperature control valves, and in this specification, these are collectively referred to as pressure control valves.

〔Effect of the invention〕

As described above, according to the pressure control valve according to the present invention, when the supply of fluid is temporarily stopped and the pressure set by the adjustment spring reaches the maximum, the movement time or movement position of the adjustment screw at this time is detected. Since the set pressure is set to 0 and power is cut off, excessive pressure will not be applied to the secondary side when fluid is supplied again, which may cause product defects or equipment damage. There is no.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing a first embodiment of the pressure control valve according to the present invention, FIG. 2 is a flowchart of the first embodiment, and FIG. 3 is a second embodiment of the pressure control valve according to the present invention. FIG. 4 is a schematic vertical sectional view showing an example, and is a flowchart of the second embodiment. 4... Valve box, 5... Valve body, 6... Valve seat, 8...
Diaphragm, 11... Adjustment spring, 13... Adjustment screw, M... Motor, 19... Disc, 20a, 2
0b... Position detection sensor, 22... Pressure sensor, 23... Setting device, 24... Three-position on/off controller, 26... Timing circuit.

Claims (1)

[Claims] 1. A motor is installed to advance and retreat an adjustment screw that adjusts the elastic force of an adjustment spring for pressure setting, and when the secondary pressure of the fluid is outside a preset target range, the motor is The motor is driven by a three-position on-off controller that controls the drive, the elastic force of the adjustment spring is adjusted, and the motor is stopped when the secondary pressure of the fluid falls within a target range. The control valve includes a timing circuit that outputs a signal when the continuous driving time of the motor in the direction of increasing the elastic force of the adjustment spring has elapsed for a certain period of time, and a secondary side fluid pressure when the signal is output from the timing circuit. A pressure control valve comprising: means for driving the motor in reverse when the pressure is approximately 0; and means for cutting off power to a three-position on-off controller when the adjusting screw moves to a free position. 2. A motor is installed to advance and retract the adjustment screw that adjusts the elastic force of the adjustment spring for pressure setting, and when the fluid pressure on the secondary side of the fluid is outside a preset target range, a motor is installed that controls the drive of the motor. In the pressure control valve, the motor is driven by a position-type on-off controller to adjust the elastic force of the adjustment spring, and the motor is stopped when the secondary pressure of the fluid falls within a target range, a position detection sensor that detects the position of the adjustment screw when the elastic force of the adjustment spring is maximum; and a position detection sensor that reverses the motor when the secondary fluid pressure is approximately 0 when the detection signal from the position detection sensor is output. A pressure control valve comprising: means for driving; and means for cutting off power to a three-position on-off controller when the adjusting screw moves to a free position.