JPS6228715Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is an electromagnetic pump drive control circuit suitable for an electromagnetic pump driven by an intermittent circuit including a control rectifying element, particularly an electromagnetic pump for supplying fuel oil to an oil combustor. Regarding.

Conventionally, a plunger type electromagnetic pump drive control circuit, as shown in _FIG . The electromagnetic pump having the excitation coil 5 is driven and stopped by opening and closing the switch _S1 . Further, the full-wave rectifier circuit 2 is usually provided with a smoothing circuit 3 including a smoothing capacitor C ₀ in order to eliminate pulsations in its output voltage.

In such a conventional circuit, as shown in FIG.
When the switch S ₁ is closed from point a to cause the intermittent circuit 4 to intermittent the DC voltage, and the switch S ₁ is opened at point b, there is a delay in which attenuating voltage is supplied to the excitation coil 5 up to point c. Characteristics appear.
This delay characteristic appears because the electric charge accumulated in the smoothing capacitor _C0 flows into the intermittent circuit 4, and the intermittent circuit 4 operates until the discharge is completed.This causes the electromagnetic pump to open the switch _S1. Even after that, due to the attenuating voltage, there is a short period of attenuated reciprocation.

Therefore, when using an electromagnetic pump as a means of supplying fuel oil to an oil combustor, switch S ₁
From the moment the power is turned off, a small amount of fuel oil is supplied to the combustor based on the damped reciprocating motion of the electromagnetic pump, and the balance between the amount of fuel oil sent to the combustor and the amount of air is lost, resulting in an explosion due to unburned gas or incomplete combustion. This may cause odor and harmful gases to be generated.

On the other hand, a device has also been proposed in which a solenoid valve is provided on the discharge side piping of an electromagnetic pump and the solenoid valve is closed in synchronization with the switch _S1 . However, with this device, there is a problem in terms of cost due to the addition of a solenoid valve, and it is difficult for the air inside the solenoid valve to escape, which must be taken into consideration, and there are problems in implementation. .

The following drive control circuit has been proposed as an improved version of this with a relatively simple configuration.

That is, as shown in FIG. 3, in addition to the switch S ₁ inserted and connected between the AC power supply 1 and the full-wave rectifier circuit 2, there is also a switch between the rectifier circuit 2 and the smoothing circuit 3.
S ₂ is inserted and connected to cut off the discharge current that attempts to flow into the intermittent circuit 4 from the smoothing capacitor C ₀ when these switches are off, thereby preventing the attenuated reciprocating motion of the electromagnetic pump after the power is cut off. It is something.

However, in this example, new problems arise in operability, such as the need to provide a time delay between the opening and closing operations of the two switches.

The present invention aims to make it possible to prevent the damping operation of the electromagnetic pump after the power is cut off using a single conventional switch by adding a simple circuit.

The present invention provides an electromagnetic pump drive control circuit comprising a rectifier circuit and a smoothing circuit to be connected to an alternating current power source, and an intermittent circuit for exciting an electromagnetic pump connected after the smoothing circuit. The common terminal of the changeover switch and the first changeover terminal are inserted and connected between them, and a discharge resistor is connected between the second changeover terminal of the changeover switch and the ground, and the changeover switch is connected to the second changeover terminal. The present invention is characterized in that the discharging resistor is connected in parallel to the smoothing circuit when the smoothing circuit is switched to the terminal.

Examples of the present invention will be described below.

FIG. 4 shows a schematic circuit configuration of the present invention, 1
is an AC power supply, 2 is a full-wave rectifier circuit, 3 is a smoothing circuit,
4 is an intermittent circuit, 5 is an exciting coil of an electromagnetic pump, S ₃
is a changeover switch provided between the rectifier circuit 2 and the smoothing circuit 3, and Rd is a low resistance for discharging the smoothing capacitor _C0 .

As is clear from Fig. 4, the changeover switch _S3
The common terminal and the first switching terminal a are inserted and connected to the line between the rectifier circuit 2 and the smoothing circuit 3. Further, a discharge resistor Rd is connected between the second switching terminal b and the earth line, and when the switching switch _S3 is switched to the second switching terminal b, the power to the intermittent circuit 4 is cut off, and A discharge resistor Rd is connected in parallel to the smoothing circuit 3.

In this drive control circuit, selector switch _S3 is
The alternating current voltage from the alternating current power source 1 is converted to direct current by the full-wave rectifier circuit 2, and further smoothed by the smoothing circuit 3, and then added to the intermittent circuit 4. 5 is periodically excited to drive an electromagnetic pump.
To stop driving the electromagnetic pump, turn the selector switch
It is sufficient to switch S ₃ to the b side in the figure, and at this time, a discharging resistor Rd is connected in parallel to the smoothing circuit 3 to prevent the intermittent circuit 4 from operating due to the discharging current from the smoothing capacitor C ₀ . Here, as the switch _S3 , when an electromagnetic pump is used to supply fuel oil to an oil combustor, a switch that is switched to the a side when the operation switch is turned on is used in conjunction with the operation switch of the combustor.

As is clear from the above configuration, this embodiment is an electromagnetic pump drive control circuit that rectifies and smoothes AC power and connects it to an intermittent circuit. By simply inserting and connecting a changeover switch and a discharge resistor between the smoothing circuit, the discharge current of the smoothing capacitor C ₀ can be prevented from flowing into the intermittent circuit when the power is cut off, thereby preventing electromagnetic It is possible to reliably prevent damped reciprocating motion of the pump.

The specific circuit configuration and operation of the first embodiment will be described below with reference to FIG.

In the figure, the full-wave rectifier circuit 2 includes rectifiers SR ₁ ~
Consisting of SR ₄ bridge-connected, smoothing circuit 3 is a resistor.
It consists of R ₀ and smoothing capacitor C ₀ . Intermittent circuit 4
includes a control rectifier SCR ₁ which is connected in series with the excitation coil 5 to the smoothing circuit 3 to turn on and off the power supply to the excitation coil 5, and further controls the excitation coil 5 by the control rectifier SCR ₁ . In order to periodically excite, a circuit that turns on a controlled rectifier SCR ₁ using a programmable unidirectional transistor (hereinafter abbreviated as PUT) Q ₁ , etc., a trigger diode TD, and a controlled rectifier SCR ₂ are used.
and a circuit that turns off the controlled rectifier SCR ₁ by, for example, the control rectifying element SCR 1.

Next, the sixth section shows the voltage waveform to the excitation coil 5.
The circuit operation will be explained with reference to the figures.

In the state shown in FIG. 5, a full-wave rectified voltage is generated by the full-wave rectifier circuit 2 and can be supplied to the smoothing circuit 3. Here, when _the switch _S3 is turned on to the a side at point a in Fig. ₆ , the result is
A reference voltage is applied to the gate of PUTQ ₁ , while
Capacitor _C3 is charged via resistor _R2 , resistor _R3 , resistor _R4 , and variable resistor _VR1 . As a result, when the charging voltage of capacitor C ₃ , i.e. the anode voltage of PUTQ ₁ exceeds the gate voltage of PUTQ ₁ , PUTQ ₁
becomes conductive and the anode current of PUTQ ₁ charges capacitor C ₁ through resistor R ₇ . When the charging voltage of the capacitor C ₁ , that is, the gate voltage of the control rectifier SCR ₁ exceeds the firing voltage of the control rectifier SCR ₁ , the control rectifier SCR ₁ becomes conductive, and the excitation coil 5 of the electromagnetic pump changes as shown in FIG. Electricity is applied at point b in the middle, and the electromagnetic pump is driven.

On the other hand, since the control rectifier SCR ₁ is made conductive, the variable resistor VR ₂ ,
Since current flows to the negative terminal of the smoothing circuit 3 via the resistor R ₈ , the resistor R ₉ , and the controlled rectifier SCR ₁ , the capacitor C ₄ is charged with the polarity shown. As a result, when the charging voltage of capacitor C ₄ reaches the breakover voltage of trigger diode TD, trigger diode TD becomes conductive, which causes the current of trigger diode TD to charge capacitor C ₂ through resistor R ₁₁ and control Increase the gate voltage of rectifier SCR ₂ . Then, when the gate voltage of the controlled rectifier SCR ₂ reaches the ignition voltage, the controlled rectifier SCR ₂
conducts, and as a result, a reverse voltage is applied to the controlled rectifying element _SCR1 by the capacitor _C4 , and the controlled rectifying element _SCR1 is turned off.

The excitation coil 5 is thus demagnetized at point c in FIG. After that, when the discharge of the capacitor C ₄ is completed, the control rectifier SCR ₁ becomes conductive again by PUTQ ₁ , and by repeating the above operation, the excitation coil 5 is periodically supplied with voltage and excited as shown in the figure. . Note that the conduction timing of the control rectifier SCR ₁ can be set arbitrarily by variable resistors VR ₁ and VR ₃ , and the turn-off timing can be set arbitrarily by variable resistor VR ₂ , and the excitation time and period of the excitation coil 5 can be freely changed. can.

Now, in order to disconnect the intermittent circuit 4 from the power supply, for example, at point d in _FIG .
When switched to the side, the connection between the rectifier circuit 2 and the smoothing circuit 3 is cut off, and at the same time, the smoothing capacitor C ₀ is switched to
Since the discharge is rapidly carried out through the discharge resistor Rd, which is sufficiently small compared to the impedance of the intermittent circuit 4 side, the operation of the intermittent circuit 4 is stopped at the same time as the switch _S3 is switched _, and the excitation coil 5 is no longer energized. cut off,
Therefore, the electromagnetic pump stops without damping and reciprocating.

This means that when an electromagnetic pump is used as a means of supplying fuel oil to an oil combustor,
The supply of fuel oil is stopped at the same time as the operation switch is turned off, thereby preventing explosions caused by unburned gas and the generation of odors and harmful gases due to incomplete combustion.

Although the present invention has been explained assuming a plunger type electromagnetic pump, the intermittent circuit 4 is not limited to the circuit configuration as in the embodiment, and can also be used to generate driving pulses for a free-running multivibrator or a blocking oscillator using transistors, for example. Many circuits can be applied, such as one that uses these oscillators as a source, or one that uses these oscillators to alternately drive controlled rectifying elements.

As explained above, the present invention rectifies and smoothes AC power and connects it to an intermittent circuit.
This is a drive control circuit that can reliably prevent the damped reciprocating motion of the electromagnetic pump when the power is cut off with a simple configuration of just connecting a changeover switch and a discharge resistor.
Ideal for electromagnetic pumps for supplying fuel oil to oil combustors.

[Brief explanation of the drawing]

Figures 1 and 3 are schematic configuration diagrams of conventional electromagnetic pump drive control circuits, Figure 2 is a diagram showing the time change of the terminal voltage of the electromagnetic pump excitation coil in Figure 1, and Figure 4 is a diagram of the present invention. FIG. 5 is a schematic diagram of an embodiment of the invention, FIG. 5 is a detailed circuit diagram thereof, and FIG. 6 is a diagram showing temporal changes in the terminal voltage of the electromagnetic pump excitation coil in the invention. In the figure, 1 is an AC power supply,
2 is a full-wave rectifier circuit, 3 is a smoothing circuit, 4 is an intermittent circuit, 5 is an excitation coil for an electromagnetic pump, _S3 is a changeover switch, _Q1 is a programmable unidirectional transistor, and TD is a trigger diode.

Claims (1)

[Scope of utility model registration request] In an electromagnetic pump drive control circuit comprising a rectifier circuit and a smoothing circuit to be connected to an AC power source, and an intermittent circuit for exciting an electromagnetic pump connected to the rear stage of the smoothing circuit, switching between the rectifier circuit and the smoothing circuit is provided. The common terminal of the switch and the first switching terminal are inserted and connected, and a discharge resistor is connected between the second switching terminal of the switching switch and the ground, and the switching terminal is switched to the second switching terminal. An electromagnetic pump drive control circuit characterized in that the discharge resistor is connected in parallel to the smoothing circuit when the smoothing circuit is turned on.