JPH0248712A - Automatic set constant flow valve - Google Patents

Abstract

PURPOSE:To speed up response by means of a simple method, to attain automatic control and to facilitate the alteration of a set flow quantity by operating the optimum displacement quantity of an adjustment means in a control meter and driving a driving means by the operated displacement quantity. CONSTITUTION:The relation of the adjustment quantity of the adjustment means and the set flow quantity is stored in a memory device in the control meter 80. When the objective set flow quantity is inputted from a set input means, the optimum adjustment quantity of the adjustment means is operated in an arithmetic unit in the control meter 80. A control signal based on the operated adjustment quantity is transmitted to the driving part 1, which is operated, and the adjusting means moves up to an objective value and stops. Thus, control is simple and the driving part is operated for the required quantity at a stretch toward the objective value. The valve is mechanically and rapidly operated, and control with rapid response is attained, whereby the set flow quantity can easily be altered.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a valve for controlling the amount of fluid flowing in a pipe, and particularly to a constant flow valve used to maintain a constant flow rate regardless of pressure fluctuations of the fluid. .

<Prior art> In general, a constant flow valve has a structure in which the main valve is directly operated by a pressure responsive member such as a diaphragm, and one side of the diaphragm receives the fluid pressure on the primary side, ((! Fluid pressure is applied, a pressure-responsive member is displaced according to the pressure difference between the negative side and the secondary side, and the valve body is operated to adjust the valve opening area and keep the amount of fluid passing constant.

When changing the set flow rate, either install a separate diaphragm on which the negative side pressure acts and a diaphragm on which the secondary side pressure acts, and change their area ratio, or select a variety of valve diameters while keeping the diaphragm area the same. Was. Therefore,
This is extremely inconvenient when changing the set flow rate frequently. Additionally, remote control and automatic control are not possible.

Conventionally, automatic control valves have been used in such cases. Automatic control valves detect the controlled variable of the controlled object, compare it with the target value, make judgments based on deviations, and process commands in the form of signals to control operating parts such as electric motors and fluid actuators that operate the valve body. It is.

When used as a constant flow valve, the flow rate in the pipe is detected with a flowmeter that outputs an electrical signal, compared with the target value input through the setting mechanism, and processed as a signal to be sent via an actuator such as an electric motor. , proportional, differential, and integral actions, so-called PID! Perform IJ control.

<Problems to be Solved by the Invention> However, when performing the above-mentioned PID control, P for determining the valve operation amount, 1. It is difficult to determine each constant of D, and a high level of skill and experience is required. In addition, in this control method, the valve is operated while comparing the actual measured value so that it approaches the target value, so the response is very poor, and it takes a long time to reach the target value, or the valve goes too far. This is because the flow rate is not controlled by the flow rate, but by adjusting the opening degree of the valve, and there is no linear relationship between the amount of operation given to the valve by the operating section such as the actuator and the flow rate. This is because control becomes complicated.

Furthermore, the automatic control valve described above is expensive. This is because the valve body must be operated directly and rapidly in small increments using an actuator such as an electric motor, which requires a high-output actuator and control I equipment that performs complex signal processing.

Therefore, the technical problem of the present invention is to provide an automatically set constant flow valve that has a simple control method, has quick response, can be remotely operated or automatically controlled, and can easily change the set flow rate, and at a low cost.

<Means for Solving the Problems> The technical means of the present invention taken to solve the above problems is to connect a valve port provided in a valve casing forming an inlet and an outlet to a pressure-responsive member such as a diaphragm. The valve is opened and closed by a valve body connected to the pressure-responsive member, and primary fluid pressure is applied to the valve port on one side of the pressure-responsive member, and the biasing force of a setting spring is applied to the other side of the pressure-responsive member. This is a constant flow valve that opens and closes the valve opening based on the balance between the two forces, allowing a fixed amount of flow to pass through.It is equipped with an adjusting means to adjust the set flow rate by changing the biasing force of the setting spring. Attach a driving means for driving, store the relationship between the set flow rate and the displacement amount of the adjustment means in a controller equipped with a setting input means, and input the desired set flow rate from the setting input means to perform the adjustment. The optimum amount of displacement of the adjusting means is calculated using a meter, and the driving means is driven by the calculated amount of displacement.

Effect〉 The operation of the above technical means is as follows.

The elastic force of the setting spring acts on one side of the diaphragm, and the primary side pressure acts on the other side, and the diaphragm is displaced by the balance of both forces. Then, according to the displacement, a valve body connected to the diaphragm opens and closes the valve port to change the valve port area and adjust the flow rate. -If the next side pressure increases, the pressure difference before and after the valve will also increase, and if the valve opening is the same, the flow rate will also increase. However, if the downstream pressure increases, the diaphragm is further displaced against the biasing force of the setting spring, and the valve body also acts to block the valve port, reducing the valve port area and increasing the flow rate. prevent.

When changing the set flow rate, all you have to do is adjust the adjustment means and change the biasing force of the setting spring. Therefore, the adjustment amount of the adjustment means (
By storing the relationship between the position (position) and the set flow rate in the storage device in the controller, and inputting the desired set flow rate from the setting input means, the arithmetic unit in the controller calculates the optimal adjustment amount for the adjustment means based on the above relationship. Calculate. A control signal based on the calculated adjustment amount is sent to the drive unit to operate it, and the adjustment means moves to a desired value and then stops. In order to move the drive means by the calculated adjustment amount and then stop, a position detection means such as a potentiometer is used, or a stepping motor controls the adjustment means or the operation shaft of the drive section itself.

<Example> An example showing a specific example of the above technical means will be described. (
(See FIG. 1) This embodiment consists of a drive section 1 and a valve section 3. Entrance 2, exit 4
A first valve seat 8 and a second valve seat 10 facing each other are arranged in a valve casing 6 forming a valve casing 6 . The flow path from inlet 2 is 2
The two valve seats are branched in both directions, and communicate with the two valve seats, respectively. A diaphragm casing 12 is fixed to the upper part of the valve casing 6 with bolts 14, and a diaphragm 18 is installed between the upper flange of the diaphragm casing and the flange of the spring case 16.
Pinch and secure. A spring receiver 20 and a valve shaft 22 are screwed to the center of the diaphragm 18 so as to sandwich the diaphragm 18 therebetween. The valve stem 22 is the diaphragm casing 1
2, and its lower end is connected to the first valve body 24.
is formed to bias the first valve seat 8 from the outlet 4 side. On the other hand, the bottom flange 28 is attached to the bottom of the valve casing 6 by the bolts 3.
4, and the second valve body 26 is arranged on the inlet 2 side of the second valve seat 10. The shaft portion of the second valve body 26 is configured such that the bearing of the bottom flange 28 moves tg within the portion 30, and is always urged toward the second valve seat by a biasing spring 32. Reference number 36 is a communicating hole. The valve shaft 22, the first valve body 24, and the second valve body 26 configured as described above are arranged on the same axis. A connection port 40 is opened in a portion of the diaphragm casing 12 that forms the diaphragm chamber 38, and is communicated with the downstream side piping 42 through a communication pipe 44.

A setting spring 46 is housed in the spring case 16, and its lower end abuts the spring receiver 20, and its upper end abuts the lower end of an adjusting screw 52 via a spring retainer 48 and a steel ball 50. The nut 54 is fitted from inside the upper part of the spring case 16, and is fixed by tightening with a holder 56 from the outside. Adjustment screw 52
By changing the elastic force of the setting spring 46, the set flow rate can be set arbitrarily.

The function of the valve part is as follows. The biasing force of the setting spring 46 acts on the upper surface of the diaphragm 18, and the primary fluid pressure acts on the lower surface of the diaphragm 18, and the valve shaft 22 connected to the diaphragm 18 is operated by the balanced state. Valve stem 2
2, the first valve body 24 and the second valve body 26 change the opening area of the valve port and adjust the flow rate while adjusting the distances from the respective opposing valve seats. - The fluid pressure on the next side acts on the first valve body in the direction of opening the valve, and acts on the second valve body in the direction of closing the valve. Therefore, the two forces cancel each other out, and the fluid pressure on the primary side does not act on both valve bodies, and only the biasing force of the biasing spring 32 acts on both valve bodies in the valve closing direction.

- When the next side pressure increases, the pressure difference before and after the valve also increases, and if the opening degree of the valve port is the same, the flow rate also increases. However, −
When the next side pressure increases, the diaphragm 18 moves upward in a convex manner against the biasing force of the setting spring 46, and the valve body also acts in the direction of closing the valve port, reducing the opening area of the valve port. to prevent the flow rate from increasing. - When the pressure on the next side decreases, contrary to the above, the diaphragm 18 bends downward in a convex shape, and the opening area of the valve port increases, maintaining the original flow rate even with a small differential pressure.

When changing the set flow rate, the biasing force of the setting spring 46 can be changed by adjusting the adjusting screw 52. In other words, the relationship between the set flow rate and the adjustment amount (displacement amount) of the adjustment screw 52 can be known.

On the other hand, the flange portion 58 of the drive unit 1 and the upper flange portion 60 of the spring case 16 are attached with bolts via a heat insulating material 62. The drive unit 1 includes a motor 64. potentiometer 66,
It consists of a reduction gear 68 and electronic components for driving a motor (not shown).

The output shaft 70 of the reducer 68 is connected to the adjusting screw 52 by a spline. In this spline fitting part, rollers 72a and 72b are provided on a roller shaft passing through the output shaft 70 in the radial direction. On the other hand, the upper part of the adjustment screw 52 is formed into a cylindrical shape, and the cylindrical part has a groove 74a in the axial direction.

b, and the rollers 52a and 52b are fitted into the grooves. Therefore, when the output shaft 70 rotates left and right, the rollers 72a and b engage with the grooves 74a and b, thereby transmitting the rotation to the adjustment screw 52.

The adjusting screw 52 is displaced in the axial direction by threaded connection with the nut 54, and the displacement is absorbed by sliding at @74a, b. Part number 76.78 is a thrust bearing.

The computer in the controller 80 stores the relationship between the aforementioned set flow rate and the adjustment amount (displacement amount) of the adjustment screw 52. Therefore, when the set flow rate is input from the setting input device 82, the adjustment amount (displacement amount) of the adjustment screw 52 is calculated from the above relationship stored in the controller 80.

The motor 64 is driven by a control signal based on the calculated adjustment amount, and at the same time, the displacement of the adjustment screw 52 is detected by a potentiometer 66. If this signal matches the calculated control signal, the motor 64 will stop.

If more precise control is required, detect the flow rate with a flowmeter that can output electrical signals, constantly compare the measured value and target value, and adjust the set flow rate if a deviation occurs after setting is complete. Based on the relationship between the adjustment amount (displacement amount) of the screw 52, the adjustment amount (displacement amount) of the adjustment screw corresponding to the flow rate difference can be recalculated to perform a correction operation.

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

The automatic setting constant flow valve of the present invention does not need to determine the constants of P, I, and D, so it is easy to control, and the valve opening function is controlled via the drive unit while comparing the target value and the actual value. Since this is not a control method that controls the flow rate, the drive unit is operated by the required amount all at once toward the target value, and the valve is mechanically operated quickly as before, allowing for fast-responsive control and making it easy to change the set flow rate. can.

In addition, when operating without installing a flow meter, once the initial setting of the drive unit is completed, there is no opportunity to operate it until the next time the set pressure is changed, and the operating time is short, so its lifespan is longer than that of an automatic control valve. Much longer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the automatic setting constant flow valve of the present invention. : Drive part: Valve part: Valve casing: Second valve seat: Second valve body 2: Inlet 4: Outlet 8: First valve seat 18: Diaphragm 26: Second valve body 46: Setting spring 80: Controller 52: Adjustment screw 82: Setting input device? +11 yen 1

Claims (1)

[Claims] 1. A valve port provided in a valve casing that forms an inlet and an outlet is opened and closed by a valve body connected to a pressure-responsive member such as a diaphragm. This is a constant flow valve in which a fluid pressure is applied, a biasing force of a set spring is applied to the other surface of the pressure responsive member, and the balance between these forces opens and closes the valve port to allow a fixed amount of flow to pass through. An adjusting means for adjusting the set flow rate by changing the biasing force of the setting spring is provided, a driving means for driving the adjusting means is installed, and a setting input means is provided for setting the relationship between the set flow rate and the displacement amount of the adjusting means. If the desired setting flow rate is inputted from the setting input means, the controller calculates the optimum displacement amount of the adjustment means, and drives the driving means by the calculated displacement amount. An automatic setting constant flow valve characterized by: