JPH05241666A - Flow rate control device - Google Patents

Abstract

PURPOSE:To attain the high speed variable control of fluid flow rate without having overshooting and undershooting, in a flow rate control device. CONSTITUTION:A flow rate valve control circuit controls electrical input to a flow rate control valve 3 which controls the fluid flow rate. The flow rate valve control circuit is provided with a variable signal generating part 9 for varying the electrical input to the flow rate control valve 3 and a signal transmitting part 13 which transmits variable signals from the variable signal generating part 9. And, the signal transmitting part 13 is equipped with combined transmitting elements parallelly providing a differential element 16 which rapidly transmits the first portion of the variable signals from the variable signal generating part 9 and a first-order time lag element which delays and transmits the last portion of the variable signals. Thus, a high speed response for the fluid flow rate to be a preset flow rate in short time is enabled and the flow rate control without overshooting and undershooting can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a flow control valve that variably controls the flow rate of fluid.

[0002]

2. Description of the Related Art Some devices for controlling the flow rate of fluids control the flow rate of liquids such as water and oil and the flow rates of gases such as gas and air. The gist of the invention, that is, the purpose and effect, is common whether the fluid is liquid or gas.
Here, for convenience, the flow rate control of gas will be described as an example.

Conventionally, there is a gas proportional valve control device as a flow rate control device of this type. The gas proportional valve is widely used in large household gas water heaters, and it controls the gas flow rate according to the amount of hot water used and the desired hot water temperature to control the amount of gas burned in the gas burner. Control valve. As shown in FIGS. 4 and 5, a conventional gas proportional valve control device has a gas proportional valve 3 disposed in the middle of a gas supply pipe 2 to a burner 1, and the gas proportional valve 3 controls the gas proportional valve 3. The proportional control circuit 4 is connected, and the gas flow rate is set by the setting dial 5.
To generate a variable signal for varying the gas flow rate, and transmit the signal to the coil 8 of the gas proportional valve 3 via the operational amplifier 6 and the transistor 7. That is, the current flowing through the proportional valve coil 8 is changed by the operational amplifier 6 and the transistor 7 according to the amount of change in the resistance value of the resistor 5 ', and the gas flow rate is controlled. Incidentally, the configuration of the gas proportional valve 3 in this case is, for example, Japanese Utility Model Publication No. 58-11979 or Japanese Patent Publication No. 59-111.
No. 30, for example.

[0004]

However, in the configuration of the conventional flow rate control device as shown in FIG. 7, when an electric signal for suddenly changing the gas flow rate is output, that is, when the value of the resistor 5'is suddenly changed, the signal is changed. Is transmitted through the operational amplifier 6 and the transistor 7 to suddenly change the current input to the coil 8 of the gas proportional valve 3. As a result, the movable part of the gas proportional valve 3 suddenly operates, and the valve opening also suddenly changes. In the conventional gas flow rate control device, when the resistance 5'is suddenly changed from the state in which the maximum combustion flow rate Qmax of the burner 1 is flowing to the minimum combustion flow rate Qmin, the flow rate change curve A of FIG. It causes a shoot.

This is because, due to the inertia of the mass and operating speed of the movable part of the gas proportional valve 3, although the current is a current equivalent to the flow rate Qmin, Qmin has passed since the movable part such as the valve body has gone too far. Settles to a valve opening equivalent to
Undershoot is caused only by Q. When this undershoot occurs, the burner of the combustion equipment causes backfire, causing a dangerous state such as overheating and misfire of the burner, and there are problems such as an increase in harmful gas components in the combustion exhaust gas. ..

When it is desired to suddenly change the gas flow rate from the minimum combustion flow rate Qmin to the maximum combustion flow rate Qmax, a sudden change in the resistance 5 ′ causes an overshoot to temporarily exceed the maximum combustion flow rate Qmax by the same principle as in the opposite case. The gas amount is supplied to the burner, and there are problems that the amount of harmful gas such as carbon monoxide CO generated increases and the rated combustion amount of the equipment is exceeded.

An object of the present invention is to solve the above conventional problems, and an object thereof is to provide a flow control device which has no overshoot or undershoot and has a high-speed response.

[0008]

In order to solve the above problems, a flow control device of the present invention is a flow control valve for controlling a fluid flow rate, and a flow valve control circuit for controlling an electric input to the flow control valve. And the flow valve control circuit,
A variable signal generator for varying an electric input of the flow control valve; and a signal transmitter for transmitting a variable signal of the variable signal generator, wherein the signal transmitter is configured to output the variable signal from the variable signal generator. A differential element that rapidly transmits the beginning portion of the variable signal and a delayed element that transmits the ending portion of the variable signal 1
And a composite transmission element in which a secondary delay element is provided in parallel.

[0009]

According to the present invention, according to the above-described structure, in the variable signal generator for varying the electric input to the flow control valve, when the signal suddenly changes, the signal transmitting unit for transmitting the variable signal to the flow control valve is the primary. Since it is a composite transmission element in which a delay element and a differential element are provided in parallel, the beginning portion of the signal is transmitted rapidly and the ending portion of the signal is transmitted with a delay. As a result, the movable part of the flow control valve operates rapidly toward the set position corresponding to the signal and slowly moves toward the set position. Therefore, the operation time of the flow control valve can reach the set position in a short time, and the overshoot can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, the variable signal generator 9 comprises a resistor 10 and a variable resistor 11 '. And the connecting portion 12
The voltage signal of is composed of a fixed resistor 14 and a capacitor 15 in the middle of one input terminal of the operational amplifier 6 of the signal transmission unit 13, and delays the end portion of the variable signal from the variable signal generation unit 9. The first-order lag element for transmission and the differential element made up of the capacitor 16 for rapidly transmitting the beginning portion of the variable signal are connected via a complex transmission element provided in parallel, and the other side of the operational amplifier 6 is connected. The input terminal of
The voltage of the connection portion 18 of the transistor 7 and the resistor 17, which are connected in series with the coil 8 of the flow rate control valve 3, is connected so as to be fed back.

In the above structure, when the variable resistor 11 'is suddenly changed, the voltage of the connecting portion 12 is suddenly changed. When the voltage of the connecting portion 12 starts to change suddenly, the operational amplifier 6 is passed through the capacitor 16.
After being rapidly transmitted to the input terminal of the capacitor and charged in the capacitor 16, the signal is slowly delayed in accordance with the constant of the first-order delay element composed of the resistor 14 and the capacitor 15. Further, in accordance with the signal voltage transmitted to the input terminal of the operational amplifier 6, a voltage is applied to the base terminal of the transistor 7,
Since the current of the coil 8 of the flow rate control valve 3 changes, the gas flow rate Q of the flow rate control valve 3 requires time t ₁ as shown by the flow rate change curve B in FIG. The flow rate changes and gradually changes from the time when the flow rate approaches the set flow rate, and there is an effect that an overshooting problem such as undershoot or overshoot does not occur.
This is the same when increasing or decreasing the fluid flow rate.

FIG. 2 is an example of a flow rate control device considered prior to the present invention. When the signal voltage is suddenly changed by the variable resistor 11 ', the transmission to the operational amplifier 6 is performed by the resistor 14 and the capacitor 1.
As a result, the gas flow rate Q becomes a slow and slow change that requires the time t ₂ as shown by the flow rate change curve C in FIG. 3, and overshoot and undershoot are prevented. However, there is a problem that it takes a long time to reach the set flow rate.
The present invention does not have such a response time problem.

The embodiment of the flow rate control device of the present invention has been described by taking the gas flow rate control as an example, but the fluid is not limited to gas, and similar effects can be obtained with liquids such as water and oil. .. For example, a faucet faucet for mixing hot water and water in a bath or the like to obtain an appropriate temperature has a mechanical hot and cold water mixing tap that has a thermo wax built-in. By using the flow rate control device of the present invention for the electronic mixing stopper, there is no overshoot or undershoot and high-speed response control, hot water or cold water does not come out due to overshoot of the valve element during mixing, and proper temperature control is possible. Possible and safe to use. Moreover, it is possible to realize a user-friendly electronic faucet that can adjust the hot water temperature and flow rate by touch operation.

[0015]

As described above, according to the flow rate control device of the present invention, the following effects can be obtained.

(1) A differential element for rapidly transmitting the beginning portion of the change signal voltage from the variable signal generating portion to the signal transmitting portion, and a differential element for delaying and transmitting the end portion of the signal voltage 1
Since the composite transmission element is provided in parallel with the next-delay element, even if the signal voltage that changes the electrical input to the flow control valve changes suddenly, the movable part of the flow control valve will move to the position set by the signal voltage. Toward the set point, it acts so as to move slowly at a point near the set position, enabling a high-speed response so that the fluid flow rate reaches the set flow rate in a short time, and overshoot or undershoot. It enables flow control without a chute.

(2) Since there is no overshoot or undershoot, and high-speed response flow rate control is possible, a user-friendly electric faucet faucet or electronic mixing tap with high-speed response can be realized by touch operation in a bath or kitchen. It will be possible.

[Brief description of drawings]

FIG. 1 is a control circuit diagram showing a configuration of a flow rate control device according to an embodiment of the present invention.

FIG. 2 is a control circuit diagram of a flow rate control device devised prior to the present invention.

FIG. 3 is an explanatory diagram of flow rate change characteristics.

FIG. 4 is a system diagram showing a system configuration of a conventional flow control device.

[Fig. 5] The same control circuit diagram

[Explanation of symbols]

 3 Flow Control Valve 9 Variable Signal Generation Section 13 Signal Transmission Section 14, 15 Primary Delay Element 16 Differentiation Element 14, 15, 16 Complex Transmission Element

Claims (1)

[Claims] 1. A flow control valve for controlling a fluid flow rate and a flow valve control circuit for controlling an electric input to the flow control valve, wherein the flow valve control circuit varies an electric input of the flow control valve. A variable signal generator for transmitting the variable signal from the variable signal generator,
The signal transmitting unit is provided with a differential element that rapidly transmits the beginning portion of the variable signal from the variable signal generating unit and a first-order delay element that delays and transmits the ending portion of the variable signal in parallel. Flow control device comprising a composite transmission element.