JPH01247801A - Open and close control device for valve - Google Patents

Abstract

PURPOSE:To enable the application of a control mechanism even to a small-sized valve by adding a position transducer and an actuator to the valve as an object for control and connecting the actuator and transducer to the body of an open and close control device via a pipe line and a cable way. CONSTITUTION:A pneumatic actuator 3 is connected to a valve stem, and a position transducer 4 is fitted to the valve stem 11. Output from the position transducer 4 is fed back to a hydraulic fluid controller 1 via a photoelectric converter 2. According to the aforesaid construction, the size of a control mechanism can be substantially reduced and, therefore, applied even to a small-sized valve.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is used for automatic opening/closing control of a valve.
This invention relates to an improvement of a positioner type valve opening/closing control device that uses optical signals.

(Prior Art) For automatic valve opening/closing control, an opening/closing control device having a structure in which a control f3 groove having a positioning function and a boosting function is combined with an air actuator is often used.

FIG. 4 shows an example of a conventional valve opening/closing control device B, the main parts of which are comprised of a motor drive section 51, a control mechanism 52, a feedback mechanism 53, an air actuator 54, and the like.

That is, when a control signal is input to the motor drive section 51, the armature 55 swings clockwise about the leaf spring 56 as a fulcrum. As a result, the lever 57 moves counterclockwise about the temporary spring 58, increasing the distance between the flapper 59 and the nozzle ω, and lowering the back pressure of the nozzle ω.

As a result, the exhaust device 61 moves to the left, and air supplied from an air source (not shown) is supplied to the air actuator 54 through the opening 62, causing the valve stem 63 to rise and open the valve.

When the valve stem mill operates, this movement causes the feedback mechanism 5
3 acts on the spring arm, and is held at a position balanced with the force generated by the input signal.

In this order, the opening/closing control device B can control the driving air sent to the air actuator 58 based on the input electric signal, and can obtain the displacement of the valve body ω in response to the displacement of the incoming cuff air @, with high precision. However, in the conventional opening/closing control device B, the drive/drive section 51, control (FI structure 52, feedback N structure 53, air actuator 54, etc.) are mechanically connected together.
There is a problem that the device B becomes extremely large and is too bulky to be applied to a small valve.

In addition, since the Z3 structure of the feedback tni 53 is first and complicated, it takes a lot of effort to make adjustments, etc., and there is also a problem in that there is a high frequency of failures and a lack of reliability.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems in the conventional one-step movement control device, namely: (1) Each of the components constituting the device is mechanically connected. Because of this, it is difficult to downsize the device.
It is difficult to apply it to small valves, and (2) the structure of the device requires power recovery, which requires a lot of effort to adjust and lacks reliability.
By compactly integrating the groove and separating it from the valve, using a piezoelectric element instead of a motor, and using optical signal input, it can be easily installed on small valves, and requires less adjustment. The present invention provides a valve opening/closing control device that is both responsive and safe without the need for a valve opening/closing control device.

(Means for Solving the Problems) The present invention includes a position detector that detects the operating position of a valve body or an actuator;
a charging converter that compares a feedback signal from a position detector with the electrical signal and outputs a signal;
The basic structure of the invention includes an actuation fluid controller that applies the control signal to the piezoelectric element and supplies or discharges the actuating fluid to the actuator based on its m34 output.

(Function) A predetermined control signal 7 is sent to the piezoelectric element 22 of the actuation fluid controller 1.
When the pressure is applied, the piezoelectric nozzle flapper descends,
The exhaust nozzle 21 is completely closed.

Since the working fluid 8 from the fluid source is introduced into the upper diaphragm chamber 19 through the pressurized channel 27, the valve body 16 is pressed downward via the holding fitting 25 of the diaphragm body 18, and the flow Channel 24 is in circulation.

At this time, since the head of the valve body 16 and the presser fitting 24 are in airtight contact, the working fluid 8 will not leak to the outside through the exhaust hole 26.

When the valve of the fluid controller 1 is opened, the working fluid 8 is supplied from the fluid source (not shown) into the chamber 3b of the actuator 3, and the valve 11 is pushed down through the diaphragm 3a, and the valve 12 is moved in the opening direction. It operates to.

On the other hand, the position detector 4 detects the operating position of the valve stem 11, and a feedback signal 9 corresponding to the operating position of the valve body 11 is input to the photoelectric converter 2. A comparison operation is performed between the electrical signal S corresponding to the signal and the feedback signal 9, and a signal corresponding to the difference between the two signals is outputted as the control signal 7 and applied to the piezoelectric element 22.

When the difference between the electric signal S and the feedback signal 9 decreases and approaches a certain setting, the mechanical output of the piezoelectric element 22 becomes unstable due to the decrease in the control signal 7, and the nozzle 21 is repeatedly opened and closed due to the flapper action. It will be done.

As a result, the pressure in the upper diaphragm chamber 19 decreases, the elasticity of the spring 17 pushes the valve body 16 upward, and the fluid control 31 closes.

When the fluid controller 1 is closed, the pressure within the chamber 3b of the actuator 3 stops increasing, and the valve body 11 is held at a predetermined position.

Note that at this time, the upper diaphragm chamber 19 of the fluid controller 1
Since the nozzle 11 is repeatedly opened and closed by the flamper 22, the pressure does not become smaller than the reaction force (restoring force) of the diaphragm body 18, and as a result, the pressure between the head of the valve t416 and the airtight rib of the presser fitting 25 is held constant, and the pressure inside the chamber 3b of the actuator 3 is held constant.

Now, if the electrical signal S decreases at this stage, ip! Itf
The l signal 7 decreases from the initial setting, and the l signal 7 of the piezoelectric element 22
The flapper action stops due to loss of mechanical power and nozzle 2
1 is a completely open state.

Then, the pressure in the upper diaphragm chamber 19 of the fluid controller 1 is further reduced, the presser metal fitting 25 is raised by the reaction force of the diaphragm body 18, and the fluid 8 in the actuator 3 is discharged through the exhaust hole 26.

As a result, the pressure within the chamber 3b decreases, the valve stem 11 is pushed upward by a spring (not shown), and the valve 12 operates in the closing direction.

By repeating the above operations, the valve stem 11 is held at a predetermined valve opening position corresponding to the magnitude of the electric signal S.

(Example) The present invention will be described below based on an example of the present invention shown in FIGS. 1 to 3.

FIG. 1 is a block diagram showing the overall configuration of a switching control device that uses air as a working fluid. 4, a power supply device 5, etc.

The working air controller 1 receives a control signal 7 from the photoelectric converter 2.
actuates the piezoelectric element 22 (piezoelectric ceramic nozzle flapper), and uses its mechanical output to control the operating air 8 supplied to the air actuator 3. The supply of air 8 and the discharge of air 8 from the air actuator 3 are controlled.

The photoelectric converter 2 compares a feedback signal 9 from a position detector 4 (described later) with an electric signal S obtained by converting the optical signal, and sends a control signal 7 corresponding to the difference between the two to the drive section of the air control device 1. The 22 piezoelectric elements that make up the system are powered by one person.

The air actuator 3 is connected to the valve body 11, and opens the valve 12 by pushing the valve body 11 downward against the elasticity of a spring (not shown).The position detector 4 is composed of a potentiometer. and the valve stem 11 or the diaphragm 3 of the air actuator 3
The open position of a is detected with respect to the reference point, and a feedback signal 9 proportional to the amount of displacement is transmitted. FIG. 2 is a longitudinal sectional view of the air controller 1 used in this embodiment.

The operating air controller 1 has an air population 13 and an air outlet 1.
4, valve seat 15, valve body 16, spring 17, diaphragm body 18, upper diaphragm chamber 19, lower diaphragm chamber 20, exhaust nozzle 21 communicating with the upper diaphragm chamber 19, piezoelectric element 22 for opening and closing the nozzle (piezoelectric ceramic It is composed of a nozzle flapper (manufactured by the manufacturer), a support frame 23, and the like. Said air population 13 and upper diaphragm chamber 1
9 through a flow path 27.

When the input signal 7 from the input setting device (not shown) or the photoelectric converter 2 is applied to the piezoelectric element 22, a mechanical output is generated in the piezoelectric element 22, and the tip of the flapper comes into contact with the nozzle 21, causing this to occur. will be closed. As a result, the upper diaphragm chamber J
9 is in a sealed state, the diaphragm body 18 is pressed downward by the pressure of the operating air 8, the valve body 16 is lowered against the spring 17, and the inlet 13 and the outlet 14 are communicated with each other.

Note that the head of the valve body 16 and the presser metal fitting 25 fixed to the diaphragm body 18 are in airtight contact, so that air flows through the exhaust hole 2.
There is no leakage to the outside through 6.

On the other hand, when the electrical signal S' decreases or the feedback signal 9 from the position detector 4 increases and the control signal 7 decreases to a certain set end, the mechanical output of the piezoelectric element 22 decreases and the tip of the flapper causes what is called vertical vibration (flapping), and the pressure within the upper diaphragm chamber 19 decreases to a constant value.

As a result, the valve body 16 is pushed upward by the spring 17, and the passage 24 is closed. However, the pressure inside the upper diaphragm chamber 19 is
As a result, the head of the valve body 16 and the pressing fitting 25
There is an airtight gap between the lower end and the lower end. As a result, the air pressure within the pressure chamber 3b of the air actuator 3 is maintained at a constant pressure.

Next, when the control signal 7 becomes even smaller than the set end due to a decrease in the electrical signal S or an increase in the feedback signal 9, the flapping operation of the flapper 22 is stopped and the nozzle 21 becomes open. As a result, the air pressure in the upper diaphragm chamber 19 is significantly reduced, a gap is created between the valve body 16 and the holding fitting 25 due to the reaction force of the diaphragm body 18, and the operating air 8 from the air actuator 3 side passes through the exhaust hole 26. It is discharged to the outside, and the valve body 11 is connected to a spring (not shown).
It operates in the valve closing direction due to the elasticity of the valve.

Note that the flow path 27 is provided with a throttle 27a,
The pressure inside the upper diaphragm chamber 19 is adjusted during the firing and flapping of the nozzle 21.

The operation of the valve opening/closing control device is as described in the section of the operation above, and its explanation will be omitted.

FIG. 3 is a circuit diagram of the photoelectric converter 2, in which the light receiving element 2
8, a frequency/voltage conversion circuit hole, a comparison calculation circuit 30, a booster circuit 31, a drive circuit 32, etc.

When an optical signal is input to a light receiving element 28 such as a photodiode through an optical fiber, an electrical signal S having the same frequency as the optical signal is output, and an electrical signal S corresponding to the frequency of the optical signal is output through a frequency/voltage conversion circuit hole. Output.

In the comparison calculation circuit 30, the voltage of the electric signal S and the voltage of the feedback signal 9 are compared, and an output P corresponding to the deviation is outputted and inputted to the drive circuit 32.

, in the drive circuit 32, the deviation signal P is boosted by the voltage of the booster circuit 31, and is sent to the piezoelectric element 22 as a control signal 7.
is input to.

In this embodiment, an air power generator is used as the power supply device, but it goes without saying that a battery or the like may also be used.

Further, in this embodiment, the operating fluid controller 1 is installed in the opening/closing control device A, but it is also possible to install it on the control valve 12 side and installing the opening/closing control device in a remote location.

Further, in this embodiment, the air controller and the control valve are configured to open by applying pressure to the diaphragm body, but it goes without saying that they may be configured to close by applying pressure.

(Effects of the Invention) In the present invention, only an actuator and a position detector are attached to the valve to be controlled, and the valve is connected to the main body of the opening/closing control device through a conduit and an electric circuit. Compared to control devices, it can be easily applied to small valves.

In addition, since the operating fluid controller is configured to operate using strain force (mechanical force) generated by a piezoelectric element, the mechanism is simpler and the controller It becomes possible to significantly downsize the
There is no contact mechanism in the electrical system, further improving safety.

Additionally, piezoelectric elements produce a relatively large, stable, and constant mechanical output (strain force and amount) with a small electrical input, making fluid controller operation much easier than conventional solenoids or motors. It is more stable than those that do, and the reliability of the opening/closing control device is improved.

Furthermore, since the input signal is transmitted using an optical signal, it is less susceptible to the effects of so-called noise and disturbances, and stable control signal transmission and valve opening/closing control can be performed. It has practical utility.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of the opening/closing control device. FIG. 2 is a longitudinal sectional view of the fluid controller used in the present invention. FIG. 3 is a circuit diagram of the photoelectric converter. FIG. 4 is an explanatory diagram of a conventional valve opening/closing control device. A Opening/closing control device 9 Feedback signal 1 Actuation fluid controller 11 Valve body 2 Photoelectric converter 12 Valve 3 Actuator 22 Piezoelectric element 4 Position detector L Optical signal 7 Control signal S Electrical signal 8 Actuation fluid patent filed by Oyama 1) Manchuria Figure 1 A Figure 4 Figure 2/' l X +51617 Figure 3 Q-

Claims (1)

[Claims] a position detector (4) that detects the operating position of the valve stem (11) or actuator (3);
) and a photoelectric converter (2) that compares the feedback signal (9) from the position detector (4) with the electric signal (S) and outputs the control signal (7); the control signal (7) is applied to the piezoelectric element (22), and its mechanical output causes the actuating fluid (8) to be applied to the actuator (3).
) A valve opening/closing control device comprising a working fluid controller (1) for supplying a working fluid (1) or discharging a working fluid (8).