JPH0960871A - Oil amount pump control circuit for petroleum combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil amount pump control circuit for a petroleum combustion device in which an overvoltage for the oil amount pump is detected by both software and hardware and a positive controlling operation for a driving circuit can be carried out even if any one of detector means is troubled. SOLUTION: An oil amount pump control circuit for a petroleum combustion device having an oil amount pump 40 electrically driven is constructed such that an overvoltage sensing circuit 50 is connected in parallel with a specified voltage power supply circuit 10, the overvoltage sensing circuit 50 is comprised of a voltage comparing means connected in parallel with the specified power supply circuit 10 and a trigger of a switching element is connected to the voltage comparing means. Then, a micro-computer 20 acting as an overvoltage sensing part separate from the overvoltage sensing circuit 50 is connected to a driving circuit 30, and the driving circuit 30 is constructed to control the driving of the oil amount pump 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for an oil quantity pump of an oil combustion equipment, and more particularly to a circuit for monitoring a voltage for driving the oil quantity pump.

[0002]

2. Description of the Related Art In a combustion apparatus such as a fan heater or a stove, which supplies fuel to a combustion section to supply fuel, fuel is generally supplied from the fuel tank to the combustion section by using an oil pump. ing. This oil amount pump is electrically operated, and the amount of fuel from the fuel tank is controlled by this oil amount pump.

A circuit for controlling a conventional oil pump is shown in FIG. FIG. 2 shows a schematic circuit diagram of only the oil pump of the combustion equipment. In FIG. 2, the commercial power supply is input to the constant voltage power supply circuit 10 through the transformer. As is well known, the constant voltage power supply circuit 10 is a circuit for producing a constant voltage such as 30 V DC from a commercial power supply. This constant voltage power supply circuit
The power supply line 10 is directly input to the oil amount pump 40, and the ground line is connected to the oil amount pump 40 via a drive circuit 30 for controlling the oil amount pump 40 such as driving and stopping. The drive circuit 30 is composed of a transistor that performs a switching operation and a resistor. The transistor has its emitter grounded, its collector connected to the oil pump 40, and its base connected to the microcomputer 20.

In the above circuit, the oil quantity pump 40 is driven according to the voltage supplied from the constant voltage power supply circuit 10. If this voltage becomes an overvoltage, the fuel tank (not shown) to the combustion section (not shown). There is a problem that the amount of fuel supplied to the fuel cell increases (hereinafter referred to as “overburning amount state”), combustion failure occurs, and carbon monoxide generation increases.

In order to solve such a problem, conventionally, the voltage supplied to the oil quantity pump 40 is monitored by the microcomputer 20 and when the voltage supplied from the constant voltage power supply circuit 10 becomes an overvoltage. Sends a signal to the base of the transistor in the drive circuit 30 to open the collector-emitter state and forcibly stop the drive of the oil quantity pump 40.

[0006]

However, in the oil quantity pump control circuit having the above configuration, the drive circuit 30 is controlled only by software control such as the microcomputer 20. If a problem occurs, there is a problem that the overfuel state continues.

In view of the above problems, the present invention detects oil overvoltage to the oil quantity pump 40 by both software and hardware, and can reliably control the drive circuit 30 even if any of the detecting means fails. An object is to provide an oil quantity pump control circuit for equipment.

[0008]

In order to solve the above-mentioned problems, according to the present invention, an overvoltage detection circuit is provided in parallel with a constant voltage power supply circuit 10 in a control circuit of an oil combustion equipment equipped with an electrically driven oil quantity pump 40. 50 is connected to the overvoltage detection circuit 50
Is constituted by connecting a voltage comparison means connected in parallel with the constant voltage power supply circuit 10 and a trigger of a switching element to the voltage comparison means, and a microcomputer 20 serving as an overvoltage detection unit different from the overvoltage detection circuit 50. Is connected to a drive circuit 30, and the drive circuit 30 controls the drive of the oil amount pump 40.

[0009]

With the above configuration, the voltage supplied from the constant voltage power supply circuit 10 to the oil quantity pump 40 can be monitored by both the overvoltage detection circuit 50 and the microcomputer 20. The Zener diode in the overvoltage detection circuit 50 is selected so that a reverse current (Zener current) does not flow at the normal voltage of the oil amount pump 40 and a Zener current flows when an overvoltage occurs. Therefore, when an overcurrent occurs, a signal is sent to the base of the transistor, the collector-emitter of the transistor in the drive circuit 30 is opened, and the oil pump 40
To stop driving.

The microcomputer 20 monitors the voltage supplied to the oil quantity pump 40 in the same manner as described in "Prior Art", and when the voltage supplied from the constant voltage power supply circuit 10 becomes an overvoltage. Sends a signal to the base of the transistor in the drive circuit 30 to open the collector-emitter state and stop the drive of the oil quantity pump 40.

[0011]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a schematic circuit diagram showing an oil quantity pump control circuit of an oil combustion apparatus of the present invention. In FIG. 1, a commercial power source is input to a constant voltage power source circuit 10 through a transformer. This constant voltage power supply circuit 10
An overvoltage detection circuit 50 is connected in parallel with. In this overvoltage detection circuit 50, the cathode of a Zener diode is connected to the power supply line of the constant voltage power supply circuit 10, the anode is connected to the base of the transistor through a voltage dividing resistor, the emitter is grounded, and the collector is driven as described later. Connected to circuit 30. The power line after the overvoltage detection circuit 50 is directly input to the oil quantity pump 40, and the ground line is connected to the oil quantity pump 40.
Via the drive circuit 30 that controls the driving and stopping of
It is connected to the oil amount pump 40. The drive circuit 30 is composed of a transistor that performs a switching operation and a resistor. The transistor has its emitter grounded, its collector connected to the oil pump 40, and its base connected to the microcomputer 20 and the collector of the transistor in the above-mentioned overvoltage detection circuit 50.

In the above structure, the transistors in the overvoltage detection circuit 50 and the drive circuit 30 can be realized by other switching elements having an electric trigger, and the Zener diode can be replaced by other electric and electronic elements having a voltage comparing means. Of course, it is preferable to use a transistor and a Zener diode in consideration of productivity, cost, and the like.

[0013]

With the above structure, it is possible to provide an oil quantity pump control circuit for an oil burning device which is inexpensive and simple but can reliably detect overvoltage, and realizes a failsafe function together with the overvoltage detection of the conventional microcomputer 20. it can.

Therefore, in the oil combustion equipment, the malfunction of the oil quantity pump 40 can be prevented, and the operation in the overfuel state can be prevented, so that the desired operation can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram showing an oil quantity pump control circuit of an oil combustion apparatus of the present invention.

FIG. 2 is a schematic circuit diagram showing a conventional oil quantity pump control circuit for an oil combustion device.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. 10 constant voltage power supply circuit 20 microcomputer 30 drive circuit 40 oil quantity pump 50 overvoltage detection circuit

Claims (1)

[Claims] 1. In a control circuit for an oil combustion equipment equipped with an electrically driven oil quantity pump, an overvoltage detection circuit is connected in parallel with a constant voltage power supply circuit, and the overvoltage detection circuit is connected in parallel with the constant voltage power supply circuit. And a microcomputer serving as an overvoltage detection unit different from the overvoltage detection circuit, is connected to the drive circuit, and the drive circuit is connected to the oil circuit. An oil quantity pump control circuit for oil combustion equipment, characterized by controlling the drive of a quantity pump.