JPS6134029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow control valve that controls secondary pressure (discharge pressure) according to the amount of current passed through an excitation coil of an electromagnet. The present invention relates to a control device for expanding control width.

FIG. 1 is a diagram showing the configuration of a flow control valve. This flow control valve consists of a control valve part 1 and an electromagnet part 5. The control valve part 1 has a primary port for supplying fluid to a primary chamber 1a. 1b is provided with a secondary port 1d for discharging fluid from the secondary chamber 1c, and also includes a valve seat 2, a valve body 3, and a diaphragm 4. Further, the electromagnet section 5 is provided with a yoke 6 and a center magnetic pole 7, and an open magnetic path section between the yoke 6 and the center magnetic pole 7 is configured in an annular shape.
A permanent magnet 8 forms a uniform magnetic field in the circumferential direction.
and an excitation coil 9, and by supplying current in a predetermined direction to the excitation coil 9, the facing sides of the central magnetic pole 7 and the permanent magnet 8 are made to have the same polarity, and a uniform magnetic repulsion force in the circumferential direction can be obtained. There is. and,
This magnetic repulsion force is applied to the control valve section 1 via the pressure equalizing plate 10.
The external force F acts on the diaphragm 4.

In the flow rate control valve configured as described above, the fluid pumped from the supply source enters through the primary port 1b and is controlled by the external force F acting on the diaphragm 4 depending on the gap between the valve seat 2 and the valve body 3, that is, depending on the valve opening degree. Its flow rate is restricted and it is discharged through a secondary port 1d to a flow nozzle (not shown). At this time, if the primary pressure in the primary chamber 1a of the control valve part 1 is P ₁ and the secondary pressure in the secondary chamber 1c is P ₂ , then F=P ₁ A _D +P ₂ A _V −P ₁ A _V ...(1) Here, A _D is the pressure receiving area of the diaphragm 4, A _V is the pressure receiving area of the valve body 3, and if the design is made so that A _D = A _V , then the formula (1) becomes F〓P ₂ A _V ……(2). In other words, the secondary pressure P ₂ of the flow control valve is the primary pressure P ₁
The external force F acting on the diaphragm 4 regardless of the fluctuation of
In other words, it can be determined by the magnetic repulsion force in the electromagnet section 5.

By the way, when controlling the temperature such as the room temperature or hot water temperature in the combustion device by controlling the fuel flow rate to the combustion device (not shown) using this flow control valve, the flow control valve is not connected to the combustion device. It is necessary to obtain a secondary pressure above a predetermined value, that is, a pressure above the lower limit secondary pressure according to the characteristics of This will lead to incomplete combustion. Therefore, the amount of current applied to the excitation coil 9 of the electromagnet portion 5 of the flow control valve is varied within the range of more than the minimum amount of current that provides the lower limit secondary pressure and less than or equal to the maximum amount of current that provides the upper limit secondary pressure. It is necessary to control the secondary pressure so that the temperature becomes .

However, as is clear from Fig. 2, the characteristics of the secondary pressure _P2 with respect to the amount of current I of the flow control valve are lower limit 2.
Even if the energization amount is increased from the minimum energization amount I _L to obtain the next pressure P ₂ L to obtain the upper limit secondary pressure P ₂ M with the energization amount I _M , and then the energization amount is decreased to the minimum energization amount I _L. The lower limit secondary pressure P ₂ L could not be obtained for the secondary pressure. It can only be reduced to the value of P ₂ L′. This is due to the characteristics of magnetic hysteresis in the magnetic path of the yoke 6, center magnetic pole 7, etc. that make up the electromagnet section 5, and the secondary pressure follows different trajectories when the amount of energization increases and when it decreases. At the amount of current at which a hysteresis loop is drawn and the secondary pressure is zero, a difference in the amount of current of ΔI corresponding to the coercive force of the electromagnet occurs. Therefore, when applying the minimum energization amount I _L to obtain the lower limit secondary pressure when the energization amount increases, when the energization amount is decreased, there is a drawback that the control width of the secondary pressure becomes very small due to the holding force. had. On the other hand, if the configuration is such that the lower limit secondary pressure P ₂ L can be obtained with the minimum amount of energization I _L ′, when the amount of energization is decreased at the time of I ₀ , as shown by the dashed line in FIG. The lower limit secondary pressure P 2 _{L'' is obtained at the minimum energization amount I L} ′ by following a different trajectory from the trajectory when decreasing when _the maximum energization amount is I _M , and this lower limit secondary pressure P ₂ L '' indicates a value smaller than the lower limit secondary pressure P ₂ L, which will cause backfire in the burner of the combustion device. Therefore,
Substantially, the amount of energization can only be reduced up to the point of I _L , resulting in a narrow control range of the secondary pressure.

The present invention was made in view of the above-mentioned drawbacks of the conventional ones, and the electromagnet is not activated until the magnetic path of the electromagnet is completely magnetized with the maximum amount of current applied from the time when the electromagnetic part of the flow control valve starts being energized. Prohibits the amount of energization from being increased or decreased by control signals, and sets the upper limit of 2 to the electromagnet.
A time signal generator is provided to generate a predetermined time signal to give the next pressure, and the lower limit secondary pressure at the minimum amount of energization is always kept at a constant value even if the amount of energization is increased or decreased by the holding force of the electromagnet according to the maximum amount of energization. It is an object of the present invention to provide a control device that can establish a minor loop that can be obtained and expand the control range of secondary pressure.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 3, reference numeral 11 indicates a flow rate control valve having the structure shown in FIG. 13 is a temperature detection device that detects the temperature of the hot air or hot water and outputs a signal according to this temperature; 14 is a set temperature and the temperature detection device 1;
15 is a flow rate control valve; 15 is an operational amplifier having a function of outputting a signal for controlling the amount of current applied to the electromagnet according to the temperature difference between the detected temperature of 3 and determining the maximum amount of current and the minimum amount of current applied; This is a time signal generator that operates so as to output a maximum amount of current for a set time to provide a predetermined upper limit secondary pressure via an operational amplifier 14 when the electromagnet section 11 starts being energized.

Therefore, in the flow control valve control device having the above configuration, first, when starting energization to the electromagnet section 5 of the flow control valve 11, the time signal generator 15 operates for a predetermined period of time, thereby causing the operational amplifier 14 to control the flow control valve. A control signal is outputted so that the maximum amount of current I _M is applied to the electromagnet portion 5 of No. 11. The flow rate control valve 11, which has been energized with the maximum amount of current I _M and obtained the upper limit secondary pressure P ₂ M, is then energized with the amount of current that corresponds to the temperature difference between the detected temperature of the heat exchange section 12 of the combustion device and the set temperature. Current is applied to control the secondary pressure. At this time, the flow control valve control device controls the secondary pressure of the flow control valve 11 within a control range between the secondary pressure P ₂ M and the lower limit secondary pressure P ₂ L determined according to the characteristics of the burner of the combustion device. is controlled. That is, in the operating characteristic diagram shown in FIG. 4, when the flow rate control valve 11 starts operating, the secondary pressure is at point A, and after that, that is, after the operating time of the time signal generator 15 ends, it is at point A. When the energization amount is decreased from , point B is reached, and the _{predetermined} 2
Next pressure P _B is obtained. Next, when the amount of current is increased from point B, point C is reached. Further, when the energization amount is reduced from the energization amount at this point and set to the minimum energization amount I _L , a point D is reached, and a predetermined secondary pressure lower than the above-mentioned secondary pressure P _B is obtained. The minor loop when the amount of current is further increased from point D is at point
Intersects the main loop (X-A) at C'.

If the amount of energization is decreased again from this point C', it will go further below the point D and the pressure will be lower than the secondary pressure P _D , but for control purposes, the amount of energization should be reduced to point C'. If the value is not increased up to a value corresponding to , but is increased to a value that reaches point C, which is larger than that, and then decreased, a minor loop trajectory from point C to point D will be taken.

Therefore, after reaching point D, increase the energization amount to point C and then decrease the energization amount to obtain the minimum energization amount I.
When the pressure is _L , the pressure always returns to point D, and a predetermined secondary pressure P _D is obtained.

Therefore, if this secondary pressure P _D is set to the lower limit secondary pressure P ₂ L, the lower limit secondary pressure P ₂ L will always be obtained with the minimum amount of current I _L.

In other words, even if the energization amount is increased or decreased after the energization reaches the maximum energization amount I _M , the lower limit next pressure P _{2 L at the minimum energization amount I L} can be maintained at a constant value, and the burner of the combustion device will not backfire. never be done. Moreover, the control width of the secondary pressure can be expanded.

Note that in the above embodiment, the time signal generator 1
The set time 5 requires a time for the magnetic path of the electromagnet to be completely magnetized (the magnetic domain is demagnetized) at the maximum energization amount I _M. Furthermore, the present invention can be widely applied to flow control valves that can control secondary discharge pressure by controlling the amount of electricity supplied to electromagnets, and can control flow rate control that can control a predetermined secondary discharge pressure regardless of fluctuations in primary suction pressure. It is not limited to valves.

As described above, the present invention provides a flow control system that controls the discharge secondary pressure of the flow control valve by increasing or decreasing the amount of current applied to the electromagnet of the flow control valve equipped with an electromagnet, using a control signal from the detection means. In a valve control device, the electromagnet is prohibited from being controlled to increase or decrease the energization amount by the above control signal from the time when energization to the electromagnet starts until the time when the magnetic path of the electromagnet is completely magnetized at the maximum energization amount. Since it is equipped with a timed signal generator that generates a predetermined timed signal that gives the maximum amount of energization to obtain a predetermined upper limit discharge secondary pressure, the upper limit secondary pressure is given for a set time when energization starts to the electromagnet. After the magnetic path of the electromagnet is completely magnetized by applying the maximum amount of current, the discharge secondary pressure of the flow control valve can be controlled by increasing or decreasing the amount of current applied to the electromagnet. Due to the coercive force of the electromagnet, it is possible to establish a minor loop in which the lower limit secondary pressure at the maximum energization amount can always obtain a constant value even if the amount of energization is increased or decreased.This has the effect of expanding the control width of the secondary pressure. play.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a flow control valve to which the control device of the present invention is applied, FIG. 2 is an operating characteristic diagram of FIG. 1, and FIG. 3 is a flow control valve control device according to an embodiment of the present invention. FIG. 4 is a block diagram showing the operating characteristics of FIG. 3. 5 is an electromagnet, 11 is a flow control valve, 15 is a time signal generator, I _M is the maximum amount of current, and P ₂ L is the lower limit secondary pressure.

Claims (1)

[Claims] 1. The amount of current applied to the electromagnet of a flow control valve equipped with an electromagnet is increased or decreased by an increase/decrease signal from a detection means, thereby controlling the discharge secondary pressure of the flow control valve. In a flow rate control device, the amount of energization of the electromagnet is prohibited from being increased or decreased by the above control signal from the time when energization starts to the electromagnet until the time when the magnetic path of the electromagnet is completely magnetized at the maximum amount of energization, and the amount of energization of the electromagnet is prohibited 1. A control device for a flow rate control valve, comprising a time signal generator that generates a predetermined time signal that provides a maximum amount of current to obtain an upper limit discharge secondary pressure. 2. Flow rate control according to claim 1, wherein the detection means is a temperature detection device, and controls the discharge secondary pressure of the flow rate control valve by giving a control signal according to the temperature to an electromagnet. Valve control device.