JPH03127210A - Automatic setting reducing valve - Google Patents

Abstract

PURPOSE:To prevent an abnormal boosting phenomenon of the secondary pressure when a pilot valve is not completely closed due to the bite of a foreign matter, etc., by cutting off the primary path linking the pilot valve. CONSTITUTION:The pressure signal received from a pressure sensor 29 attached to a secondary pipeline 5 is inputted to a controller 28 together with the target value of set pressure received from a set input device 30. Then a motor is continuously driven until the deviation is equal to zero between the pressure signal and the target set pressure. At the same time, the controller 28 controls the open/close of a motor-driven valve 31 provided to a primary path 12 linking a pilot valve 9. Then the position signal of a control screw 18 which is detected by a potentiometer 21 is inputted to the controller 28. The valve 31 is closed when the deviation is not equal to zero between the secondary pressure and the target set pressure even though the screw 18 is turned maximum in the direction where the secondary pressure is reduced. Thus an abnormal boosting phenomenon of the secondary pressure can be prevented.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention operates the elastic force of the pressure setting spring of a pilot pressure reducing valve with an actuator to bring the fluid system on the secondary side to a predetermined lower pressure than the primary side. This invention relates to an automatic setting pressure reducing valve that maintains the pressure.

The pilot type pressure reducing valve drives the pilot valve by the displacement of the diaphragm, and indirectly operates the main valve such as the piston valve by opening and closing the valve to pylon 1, adjusting the amount of fluid passing through, and reducing the pressure on the secondary side. The pressure is maintained at a value corresponding to the elastic force of the pressure setting spring.

The diaphragm is tightened by the fluid pressure on the secondary side on one side and the elastic force of a pressure setting spring operated by an adjustment screw on the other side, and if the two swords are unbalanced, they will be displaced to a parallel position.

To change the elastic force of the pressure setting spring, manually operate the adjustment screw while using the pressure gauge attached to the secondary side. Therefore, it is extremely inconvenient to frequently change the set pressure, and remote control or automatic control is not possible.

Prior Art Therefore, in Japanese Patent Application No. 59-207779, the applicant proposed a technique for operating the adjusting screw with an actuator. This detects the deviation between the fluid pressure on the secondary side and the set pressure target (direct), and drives the actuator until the deviation becomes zero.

When the set pressure target value is input, the actuator is automatically driven and set to the target value.

Problems to be Solved by the Invention In the above system, if the pilot valve cannot be completely closed due to foreign matter such as dust or scale getting caught, there is a problem in that the pressure on the secondary side increases to the pressure on the primary side. .

In other words, due to the increase in secondary pressure, the actuator is driven so that the deviation from the set pressure target value becomes zero, but since the pilot valve cannot be completely closed, the main valve cannot also be closed. .

Therefore, a technical problem of the present invention is to prevent an abnormal increase in the secondary side pressure when the pilot valve cannot be completely closed.

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problems is to connect an actuator to the adjustment screw of a pilot-operated pressure reducing valve, and adjust the fluid pressure on the secondary side and the set pressure target. In the actuator that drives the actuator so that the deviation from the value becomes zero, a position detection means for detecting the position of the adjustment screw is provided,
A valve means is disposed in the primary passage communicating with the pilot valve.
．． The valve means is opened and closed by commands from the position detection means.
It is something.

action The operation of the above technical means is as follows.

The actuator is driven so that the deviation between the secondary side pressure and the set pressure target value becomes zero. When the pilot valve cannot be completely closed due to foreign matter being caught, the secondary pressure increases, so the actuator rotates the adjustment screw in a direction that decreases the secondary pressure. Then, the position detection means detects that the adjustment screw has been rotated to the maximum in a direction to lower the secondary side pressure, and the valve means disposed in the primary side passage communicating with the pilot valve is closed. Therefore, if the pilot valve cannot be completely closed due to foreign matter being caught, the primary passage communicating with the pilot valve is shut off, thereby preventing an abnormal increase in the secondary pressure.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1).

An inlet 2 and an outlet 3 are formed in the main body 1 and connected to a negative side pipe 4 and a secondary side pipe 5. The inlet 2 and the outlet 3 communicate through a valve port 6. A main valve 7 that opens and closes a valve port 6 is connected to a piston 8.

The introduction of pressure to the upper surface of the piston 8 is controlled by a pilot valve 9. The pilot valve 9 is composed of a pilot valve seat 10 and a pilot valve body 11. The pilot valve body 11 is urged upward by a spring disposed below it.

The pilot valve 9 is located between the primary passage 12 and the passage 13 communicating with the space above the piston 8, and is operated by a diaphragm 15 elastically biased by a pressure setting spring 14.

The lower end of the pressure setting spring 14 is in contact with the upper surface of the diaphragm 15 via a spring receiver. The upper space of the diaphragm 15 is connected to the outside air through a passage 16, and the lower space is connected to the outside air through a passage 17.
through which it is connected to outlet 3.

Therefore, when the diaphragm 15 is displaced downward, the pilot valve body 11 is pushed down, and the fluid in the inlet 2 is transferred to the passage 12.
13 and above the piston 8, the main valve 7 is pushed down by the piston 8, the valve port 6 is opened, and the fluid at the inlet 2 flows to the outlet 3.

Furthermore, when the diaphragm 15 is displaced upward, the pilot valve body 11 is pushed up by the spring and the passage 12 is closed, and the fluid above the piston 8 escapes to the outlet 3 through the orifice opened in the piston, and the piston 8 and the main The valve 7 is pushed up by the spring and the valve port 6 is closed.

The lower end of the adjusting screw 18 touches the upper end of the pressure setting spring 14 via a spring support member, and the amount of compression of the pressure setting spring 14 is adjusted by advancing and retreating as the adjusting screw 18 rotates, and the elastic force acting on the diaphragm 15 Power is adjusted.

Connect the seventh cutter to the adjusting screw 18.

The actuator section includes a motor 19, a speed reducer 20, a tension meter 21, and electronic components for driving the motor 19 (not shown).

The output shaft 22 of the speed reducer 20 and the adjustment screw 18 are spline-coupled. This spline fitting part has an output ll+l1
A roller 23a on the 1-ra shaft penetrates through the 122 in the radial direction.
The upper part of the adjustment screw 18 is formed into a cylindrical shape, and a groove 24a is formed in the cylindrical part in the axial direction.

24b is formed, and the rollers 23a and 23b are fitted one inch into the groove. Therefore, when the output shaft 22 rotates left and right, the rollers 23a, 23b and 24a, 24
b are engaged with each other and transmit the rotation to the adjustment screw 18. The adjusting screw 18 is displaced in the axial direction by screw connection with the nut 25, and the displacement is absorbed by sliding in the grooves 24a and 24b.

Reference numbers 26.27 are thrust bearings.

The motor 19 is driven by a command from the regulation 5128. That is, the adjustment unit 28 is equipped with a pressure signal from the pressure sensor 4 no 29 attached to the secondary side piping 5, and a setting input device 30.
The set pressure target value inputted from is input, and the motor 19 is driven until the deviation between the two becomes zero. Further, the controller 28 controls opening and closing of an electric valve 31 disposed in the primary passage 12.

That is, the controller 28 is manually inputted with the δ signal of the adjusting screw 18 detected by the potentiometer 21, and the adjusting screw 18 is
If the deviation between the secondary (I11 pressure) and the set pressure target (direct) is not within the range even though the secondary (I11) pressure is rotated to the maximum in the direction of lowering the secondary side pressure, the electric valve 31 is closed.

Effect of the invention The present invention produces the following unique effects.

As described above, according to the present invention, it is possible to obtain an automatically setting pressure reducing valve that can prevent an abnormal increase in the secondary side pressure.

[Brief explanation of the drawing]

FIG. 1 is a diagram in which a block diagram for control is superimposed on a sectional view of an automatically set pressure reducing valve according to an embodiment of the present invention. 6: Valve port 8: Piston 12 primary side passage 15: Diaphragm 19: Motor 29: Pressure sensor 31: Electric valve 4 8 8 0 Main valve Pilot valve Pressure setting spring Adjustment screw Controller setting input device

Claims (1)

[Claims] 1. An actuator is connected to the adjustment screw of a pilot type pressure reducing valve, and the actuator is driven so that the deviation between the fluid pressure on the secondary side and the set pressure target value becomes zero,
The automatic setting pressure reducing valve is provided with a position detection means for detecting the position of an adjustment screw, the valve means is arranged in a primary side passage communicating with a pilot valve, and the valve means is opened and closed by a command from the position detection means.