JPS5845628B2 - Valve opening/closing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for opening and closing a valve using a double-acting pneumatic actuator.

A pneumatic actuator that opens and closes a valve using operating air pressure has a function of supplying and discharging operating air to both pressure chambers in a cylinder with a built-in piston, or both pressure chambers in a diaphragm case with a built-in diaphragm. A so-called double-acting pneumatic actuator that reciprocates a piston or a diaphragm, and
As described in Publication No. 8, the piston or the diaphragm is actuated by supplying working air to one pressure chamber in the cylinder containing the piston or one pressure chamber in the diaphragm case containing the diaphragm, It is well known that there are so-called single-acting pneumatic actuators in which a piston or a diaphragm is moved back by a spring provided in the other pressure chamber.

When the latter single-acting air actuator is applied to open and close a valve, if the pressure of the working air decreases due to a failure in the compressor or working air supply pipe, the piston or diaphragm will return to its original position due to the spring force of the other pressure chamber. The valve can be automatically placed in the fully open or fully open position.

However, when the former double-acting pneumatic actuator is applied to a valve, compared to the case when the latter single-acting pneumatic actuator is applied, it is smaller because it does not have a spring for return operation, and both reciprocation and reciprocation are electrically operated. Although it has features such as fast operation speed even though it operates under pressure, if the pressure of the operating air decreases due to a failure in the compressor that is the source of the operating air or in the operating supply pipe, the piston or diaphragm will not operate. Since the valve that is opened and closed by the double-acting pneumatic actuator stops at that point, the valve that is opened and closed by the double-acting pneumatic actuator will stop at the momme position in the opening state at the predetermined operating pressure drop, and will not be fully closed or fully open, so it will not operate. The safety of the valve against air pressure drop was low.

The present invention provides a method for opening and closing a valve in a fluid piping via a double-acting actuator that reciprocates with working air as described above, and when there is a failure or the like in the working air pressure source of the working air, the valve is opened and closed. The purpose of this is to automatically bring the valve in the fluid piping into a fully closed or fully open state when the actuator becomes inoperable due to a drop in air pressure.

For this reason, the present invention provides a valve opening/closing system comprising a double-acting pneumatic actuator that opens and closes a valve in a fluid piping, and an operating means that supplies and discharges working air from a working air pressure source to both pressure chambers of the actuator. In the apparatus, a pressure accumulator with a check valve for working air and pressure detection means are provided in a working air supply pipe line from the working air pressure source to the operating means, and a pipe leading from the operating means to one pressure chamber of the actuator. A switching means is provided in the passageway for supplying air from the pressure accumulator to one of the pressure chambers in association with the pressure detection means when the working air pressure of the working air pressure source decreases; The pipe line leading to the other pressure chamber in the actuator is provided with atmospheric switching means that opens the other pressure chamber to the atmosphere in conjunction with the pressure detection means when the working air pressure of the working air pressure source decreases. It is structured as follows.

With this configuration, when the working air is normal and above a predetermined level, the pressure is stored in a pressure accumulator with a check valve, and in an abnormal situation when the working air pressure from the working air pressure source drops below a predetermined level, the pressure is stored in the accumulator in advance. By supplying the stored pressure to one pressure chamber in the actuator using the switching means and opening the other pressure chamber in the actuator to the atmosphere using the atmospheric switching means, the valves in the fluid piping can be automatically operated. It performs the action of fully opening or fully opening.

The drawings of the embodiment will be explained below.
As shown in the figure, there is a double-acting pneumatic actuator 3 that opens and closes a valve 2 provided in a fluid pipeline 1, and a double-acting pneumatic actuator 3 that supplies working air from a working air pressure source 4 such as a compressor to both pressure chambers of the actuator 30. an operating means 5 for operating the actuator by supplying and discharging the actuator, and a pressure accumulator 6 for operating air from the operating air pressure source 4 and means 7 for detecting the pressure of the operating air; Switching means 8 for switching and connecting the pressure accumulator 6 to one pressure chamber of the actuator and opening the other pressure chamber of the actuator to the atmosphere if the means detects a decrease in the operating air pressure. The air switching means 9 is specifically constructed as shown in FIG. 2.

In this figure, a double-acting pneumatic actuator 3 connects a valve stem 12 of a valve 2 to a piston 11 in a cylinder 10, so that when the piston 11 descends, the valve 2 is closed, and when the piston 11 rises, the valve 2 is opened. It has become.

The working air supply pipe 13 from the working air pressure source 4 is connected to a pressure reducing valve 14 that adjusts the pressure to a predetermined working air pressure, and from the pressure reducing valve 14 to two booster relays 15 and 16, which are an example of the operating means 5. One booster relay 15 is connected to the upper pressure chamber 20 of the actuator 3 via pipes 18 and 19, and the other booster relay 1
6 is a lower pressure chamber 22 of the actuator 3 via a pipe 21.
and both booster relays 15 and 16 are connected to
When a signal to close the valve 2 comes from the positioner 23 associated with the valve stem 12 of the valve 2, one booster relay 15 supplies working air to the upper pressure chamber 20, while the other booster relay 16 supplies operating air to the lower pressure chamber 22. is opened to the atmosphere, and when a signal is received from the positioner 23 to open the valve 2, one booster relay 15 opens the upper pressure chamber 20 to the atmosphere, while the other booster relay 16 supplies working air to the lower pressure chamber 22. configured to supply.

The pressure accumulator 6 is connected to the working air supply pipe 13 via a check valve 24, and the pressure accumulator 6 is connected to the pipes 18 and 19 between the one booster relay 15 and the upper pressure chamber 20. A diaphragm-type three-way valve 26 having the functions of both the pressure detection means 7 and the switching means 8 is provided at the point where the pipe line 25 from the container 6 is connected. The working air pressure supply pipe 13 is connected to the separated lower chamber 29 via a pipe 30, while the upper chamber 31 of the diaphragm is provided with a spring 32 that biases the diaphragm 28 downward. When the pressure in line 13 is equal to or higher than the regulating set pressure of pressure reducing valve 14, diaphragm 2
The valve body 33 interlocked with the pipe 25 closes the pipe 18,1
When the pressure in the working air supply pipe 13 becomes lower than the adjustment set pressure of the pressure reducing valve 14, the valve body 33 is lowered by the force of the spring 32, closing the pipe 18 and communicating the pipe 25 to 19. The three-way valve 26 is configured to operate as shown in FIG.
A reset valve 34 is provided for opening the upper chamber 31 of the diaphragm to the atmosphere.

In addition, the other booster relay 16 and the lower pressure blade chamber 22
A normally closed diaphragm valve 35, which is an example of atmospheric switching means 9 for opening the lower pressure chamber 22 to the atmosphere, is connected to the conduit 21 that connects the three-way valve 26 to the upper pressure chamber 20. A diaphragm type regulating valve 36 that opens when the pressure in the pipe 19 is higher than the adjustment set pressure of the pressure reducing valve 14 is connected to the pipe 19, and the outlet of the regulating valve 36 is connected to the three-way valve 26. Pipes 38 and 39 are connected to the upper chamber 31 of the diaphragm and the diaphragm chamber 37 of the diaphragm valve 35.
It is to be connected and admonished.

In this configuration, when the pressure in the working air pressure source 4 is normal, in other words, at a predetermined pressure, the three-way valve 26 closes the pipe 25 while communicating the pipes 1B and 19, so that the actuator 3, the working air adjusted to a predetermined set pressure by the pressure reducing valve 14 is supplied to the booster relay 15 or 1.
6, the valve 2 is opened and closed by the actuator 3.

During this opening/closing operation, if the pressure in the working air supply pipe 13 falls below the adjustment setting value of the pressure reducing valve 14 due to a failure in the working air pressure source 4 such as a compressor, the three-way valve 26 Closing the conduit 18 and conduit 25,
19, the air pressure in the pressure accumulator 6 is sent to the upper pressure chamber 20 via the pipes 25 and 19, and at the same time, the air pressure in the pressure accumulator 6 causes the regulating valve 3
6 is opened, and the air pressure of the pressure accumulator 6 acts on the upper chamber 31 of the diaphragm of the three-way valve 26 to maintain the above-mentioned switching state, and the diaphragm valve 35 is opened by the air pressure of the pressure accumulator 6, reducing the lower pressure of the actuator 3. Since the chamber 22 is opened to the atmosphere, the piston 11 in the actuator 3 is lowered by the air pressure supplied to the upper pressure chamber 20, thereby closing the valve 2.

That is, when the pressure of the working air for the actuator 3 decreases, the actuator 3 fully opens the valve 2 using the air pressure previously stored in the pressure accumulator 6. In this fully closed state, the upper chamber 31 of the diaphragm of the three-way valve 26 and a pressure accumulator 6 in the diaphragm chamber 37 of the diaphragm valve 35.
Air pressure is constantly applied by the relay valve 36, and the three-way valve 2
6 maintains the air pressure of the pressure accumulator 6 in a state where it acts on the upper pressure chamber 20, and the diaphragm valve 35 maintains the state in which the lower pressure chamber 22 is opened to the atmosphere, so that the operating air pressure source 4
Even if the pressure returns to its original state, the actuator 3 will not automatically start operating immediately, so it is safe.

When the pressure of the working air pressure source 4 returns to its original state, the reset valve 34 provided in the upper chamber 31 of the diaphragm of the three-way valve 26
By opening the air pressure and releasing the air pressure, the three-way valve 26 closes the pipe 25 from the pressure accumulator 6 and switches back to communicating the pipes 18 and 19. At the same time, the diaphragm valve 35 closes, so the actuator Operating air from the pressure reducing valve 14 is sent to the valve 3 under the control of both booster relays 15 and 160, and the valve 2 is opened and closed by the actuator 3.

In this case, when the pressure of the working air decreases, the valve 2
In order to fully open the three-way valve 26, which is an example of the switching means 8, connect the pipe 2 to the lower pressure chamber 22 of the actuator 3.
1, a diaphragm valve 35, which is an example of the atmospheric switching means 90, is provided for each pipe line 19 to the upper pressure chamber 20 of the actuator 3, or the pipe lines 19 and 2 to the actuator 3 are
1 upside down and connect the pipe line 19 to the lower pressure chamber 22 and the pipe line 21 to the upper pressure chamber 20, respectively. By providing a four-ray manual switching valve 40 as shown in FIG. 2, it is possible to switch the valve 2 between fully open and fully open as desired when the pressure of the working air decreases.

In addition, if there is no pressure reducing valve 14 in the working air supply lines 13 and 17 from the working air pressure source 4 to the booster relays 15 and 16 serving as the operating means 5, the pressure reducing valve 14 is removed from the booster relay 15 as shown in FIG. The pipe line 18 is connected to the regulating valve 3 via the pipe line 41.
A similar effect can be obtained by connecting to the diaphragm chamber 42 of No. 6.

Although the embodiments have been described above, the present invention comprises a double-acting pneumatic actuator that opens and closes a valve in a fluid piping, and an operating means that supplies and discharges working air from a working air pressure source to and from a dual blade chamber of the actuator. A valve opening/closing device comprising: a pressure accumulator with a check valve for working air and pressure detection means in a working air supply pipe line from the working air pressure source to the operating means; The pipe line leading to the pressure chamber is provided with a switching means configured to supply air from the pressure accumulator to one pressure chamber in association with the pressure detection means when the working air pressure of the working air pressure source decreases. , a conduit leading from the operating means to the other pressure chamber in the actuator is configured to open the other pressure chamber to the atmosphere in conjunction with the pressure detection means when the operating air pressure of the operating air pressure source decreases. A valve opening/closing device characterized by being equipped with an atmosphere switching means, in which when the valve is opened/closed by a double-acting pneumatic actuator, if the pressure of working air to the actuator decreases, the valve is stored in a pressure accumulator in advance. Since the valve is fully closed or fully opened using air pressure, the valve does not stop at an arbitrary opening due to a drop in operating air pressure, improving safety for valves that use double-acting pneumatic actuators. have an effect.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a schematic diagram, FIG. 2 is a diagram of the first embodiment, FIG. 3 is a diagram of the second embodiment, and FIG. 4 is a diagram of the third embodiment. be. 1... Piping, 2... Valve, 3...
・Actuator, 4...Operating air pressure source, 5...
...Operating means, 6...Pressure accumulator, 7...
...Pressure detection means, 8...Switching means, 9...
...Atmospheric switching means.

Claims (1)

[Claims] 1. A valve opening/closing device comprising a double-acting pneumatic actuator that opens and closes a valve in a fluid piping, and an operating means that supplies and discharges working air from a working air pressure source to both pressure chambers of the actuator. A pressure accumulator with a check valve for working air and a pressure detection means are provided in a working air supply pipe line from the air pressure source to the operating means, and a pipe line leading from the operating means to one pressure chamber of the actuator is provided with the above-mentioned pressure chamber. A switching means is provided in association with the pressure detecting means to supply air from the pressure accumulator to one pressure chamber when the working air pressure of the working air pressure source decreases, while supplying air from the pressure accumulator to one pressure chamber from the operating means to the other pressure chamber. The pipe line leading to the chamber is provided with an atmosphere switching means configured to open the other pressure chamber to the atmosphere in conjunction with the pressure detection means when the working air pressure of the working air pressure source decreases. Valve opening/closing device.