JPH05332513A - Operation control method for combustion equipment - Google Patents

Abstract

PURPOSE:To prevent an excessive load in a combustion fan and enable a normal combustion to be continued by a method wherein an amount of air required for combustion is controlled in response to the number of revolution as well as a conducting current value. CONSTITUTION:A motor 9 for a combustion fan is constructed to be controlled and driven by a magnetic pole sensing circuit, a motor driver 11 and a diode circuit. The number of revolution of the motor 9 is detected by an FG signal got from the motor driver 11 and in turn its output current is detected, the number of revolution is calculated in reference to the output current, the detected output current is compared with a set current value and a signal S1 is outputted to the motor driver 11 in such a manner that it may become a set current value, the detected number of revolution is compared with the number of revolution got through the calculation and then a state of the motor 9 is judged. With such an arrangement, it is possible to restrict a damage of equipment and further to avoid a dangerous state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the operation of combustion equipment.

[0002]

2. Description of the Related Art Conventionally, in combustion equipment, the air required for combustion in a burner is supplied by a combustion fan. As a method of controlling the amount of air required for combustion (blowing amount), a combustion fan is used. The method of controlling the rotation speed of the motor and the method of controlling the current value of the motor can be mentioned. Compared with the former, the latter is known to improve the wind resistance performance of the device in order to keep the amount of work (blowing amount) more constant.

[0003]

However, on the other hand, in the control system using only the current value, if the exhaust port is blocked due to some abnormality, the rotation speed of the motor of the combustion fan rises abnormally. There is a possibility that a problem such as an excessive load being applied to the combustion fan or a problem that normal combustion cannot be continued may occur. The present invention has been made to solve such a problem.

[0004]

In order to solve the above-mentioned problems, the present invention provides a method for controlling the amount of air required for combustion in a burner of a combustion device by controlling the value of current supplied to a motor in a combustion fan. The rotation speed is detected together with the current value of the motor in the combustion fan and compared with the allowable rotation speed of the motor corresponding to the current value in normal operation. If the rotation speed of the motor is outside the allowable rotation speed, it is determined that an abnormal condition has occurred. It is characterized in that combustion is interrupted or notified.

[0005]

When the combustion device is started, the fan is rotated by the rotation of the motor of the combustion fan, the air is supplied to the burner in an amount necessary for combustion, and the fuel is supplied to the burner to start combustion. In this case, the current value supplied to the motor of the combustion fan is detected, and a control signal is given to the motor to supply the amount of air corresponding to the preset current value. Furthermore, at that time, the rotation speed of the motor is detected and compared with the allowable rotation speed corresponding to the current value in the normal operation,
If the number of rotations of the motor in the blower is outside the allowable number of rotations, it is determined that an abnormal state has occurred and combustion is interrupted or a notification is given.

[0006]

EXAMPLE An example of a combustion device for carrying out the operation control method of the combustion device according to the present invention will be described below in detail. In FIG. 1, reference numeral 1 is a combustion device,
That is, a water heater is shown, and this water heater 1 supplies hot water to a bathtub, a kitchen, a washroom, etc. indoors, for example, while introducing air required for combustion from the outside and exhausting combustion gas to the outside through an exhaust pipe 2. It is installed so as to be discharged through. That is, the hot water supply device 1 supplies gas to the gas burner 3 as a fuel, allows the introduced cold water to pass through the heat exchanger 4 for heat exchange, discharges the hot water, and supplies the hot water to each of the above-mentioned locations. The heat exchanger 4 and the gas burner 3 are built in a combustion chamber 5, and a fuel gas supply valve 6 is arranged below the gas burner 3 to further supply air required for combustion to a combustion surface of the gas burner 3. The combustion fan 7 is installed. Further, the water heater 1 includes a combustion fan 7 and the like,
It has a control unit 8 that sends and receives a detection signal and an operation control signal to and from the components inside the water heater 1.

As the combustion fan 7, for example, a DC brushless motor 9 provided integrally with the fan can be applied. As shown in FIG. 2, the motor 9 is controlled and driven by a magnetic pole sensor circuit 10, a drive control means 11 (hereinafter referred to as a motor driver 11), and a diode circuit 12.

The magnetic pole sensor circuit 10 can be composed of three Hall elements. The magnetic pole sensor circuit 10 detects the magnetic poles of the motor 9, obtains a phase output according to the position of each magnetic pole, and supplies the phase output to the motor driver 11.

The motor driver 11 has a dedicated IC
Can be used. The IC serving as the motor driver 11 incorporates a position detection circuit for detecting the rotational position of the shaft of the motor 9, an FG output circuit, and a transistor switching circuit, and supplies drive power supplied via the diode circuit 12 to the IC. Based on the phase output from the magnetic pole sensor circuit 10, the transistor switching circuits are sequentially turned on and applied to the motor 9 as an excitation signal or a square wave FG signal to the control unit 8. Further, the motor driver 11 is provided with a terminal for detecting an output current supplied to the motor 9, and a resistor R, for example, is connected between this terminal and GND. The configuration is such that the output current is obtained.

As shown in FIG. 3, the control unit 8 controls the motor 9 by the square wave FG signal from the motor driver 11.
Rotation speed detection means 13 for detecting the rotation speed of the motor, current detection means 14 for detecting the output current from the potential of the resistor R at the output current detection terminal, and rotation for calculating the rotation speed from the detected output current. The number calculation means 15, a comparator 18 that compares the detected output current with a set current value, and outputs a signal S1 to the motor driver 11 so that the set current value is obtained, and the rotational speed detection means 13 Comparison determination means 1 for determining the state of the motor 9 by comparing the signal relating to the rotation speed with the rotation speed obtained by the rotation speed calculation means 15.
6 and. Then, the signal relating to the determination from the comparison determination means 16 is given to the notification means 17, for example, a buzzer or the like. A light emitting display means can be applied to the notification means 17.

As shown in FIG. 4, the rotation speed calculation means 15 performs a function calculation indicated by an output current I-motor rotation speed N curve. At that time, the motor rotation speed N corresponding to the output current I obtained by the function calculation is set to the allowable rotation speed, and therefore the lower limit rotation speed N (MI
N) and the upper limit rotation speed N (MAX) are defined. Also,
The rotation speed calculation means 15 has a data table of output current I-motor rotation speed N, and it is also possible to obtain the motor rotation speed N corresponding to the output current I. Also at this time,
The lower limit speed N (M of the motor speed N corresponding to the output current I
IN) and the upper limit speed N (MAX) are defined.

The water heater 1 according to the present invention is as described above, and its operation will be described below. When the water heater 1 is started, the motor 9 of the combustion fan 7 rotates and the gas burner 3
The amount of air required for combustion is supplied to the fuel gas, the fuel gas is supplied to the gas burner 3, and the fuel is ignited by an ignition means (not shown) to start combustion.

In the motor 9, the phase output from the magnetic pole sensor circuit 10 is introduced into the motor driver 11 and shaped into a rectangular position detection signal corresponding to the rotational position of the motor 9, and based on this signal, a diode is detected. The drive power supplied to the circuit 12 is sequentially turned on by the transistor switching circuit and is given to the motor 9 as an excitation signal to rotate the motor 9.

The control unit 8 controls the motor 9 from the square wave FG signal from the motor driver 11 by the rotation speed detecting means 13.
To detect the rotation speed of. Further, the current detection means 14 detects the output current from the potential of the resistor R at the output current detection terminal of the motor driver 11, and outputs a control signal S1 to the motor driver 11 so that the current value for setting is reached.
And the rotational speed calculation means 15 calculates a functional expression to obtain the rotational speed corresponding to the output current. The value of the rotation speed obtained by the rotation speed calculation means 15 is a value when the motor 9 is in the normal state. Then, the actual rotation speed detected by the rotation speed detection means 13 and
The comparison and determination means 16 determines the number of rotations calculated by the rotation speed calculation means 15.

At this time, the actual rotation speed N is the lower limit rotation speed N.
If it is larger than (MIN) and smaller than the upper limit rotation speed N (MAX), it can be determined that normal operation is performed. On the other hand, if the rotation speed N is a value outside the range of the lower limit rotation speed N (MIN) to the upper limit rotation speed N (MAX), it is determined that an abnormal state has occurred and the notification means 1
An emergency stop of the water heater 1 can be performed by giving a signal notifying the abnormal state to 7.

For example, as shown in FIG. 4, when the actual number of revolutions N fluctuates toward the A side, exhaust is blocked due to the following factors. That is, as such a factor, it is possible that the exhaust is blocked by a strong wind such as a typhoon, the fan or rotor shaft spins idle, or the exhaust stack is blocked by a bird's nest. On the other hand, the actual speed N
However, when it is changing to the B side, it can be considered that the exhaust is promoted by the strong wind and that the rotor shaft is fixed. If the above-mentioned state progresses extremely, the rotational speed N will deviate from the allowable rotational speed within the set range, and a signal for informing the abnormal state is given to the informing means 17 that an abnormal state has occurred, and the water heater is immediately sent. Since the operation of No. 1 can be stopped, damage to the equipment can be suppressed, and a dangerous state can be avoided.

[0017]

As described above, according to the present invention, the amount of air required for combustion in the burner of the combustion equipment is controlled by the value of the current supplied to the motor in the combustion fan, and the rotation speed of the motor is detected. Then, as compared with the permissible rotation speed of the motor in the normal operation, if the rotation speed of the motor is outside the permissible rotation speed, the combustion is interrupted or an alarm is generated as an abnormal state occurs, so that damage to the equipment is prevented. It can be suppressed and dangerous situations can be avoided.

[0018]

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts of a water heater according to the present invention.

FIG. 2 is a block diagram of a drive control circuit of a motor in the combustion fan of the water heater shown in FIG.

FIG. 3 is a block diagram showing an example of a control unit of the water heater shown in FIG.

FIG. 4 is a graph showing a relationship between a motor current value and a rotation speed of the combustion fan of the water heater shown in FIG. 1.

[Explanation of symbols]

 1 Water Heater 2 Exhaust Pipe 3 Gas Burner 4 Heat Exchanger 5 Combustion Chamber 6 Fuel Gas Supply Valve 7 Combustion Fan 8 Control Unit 9 Motor 10 Magnetic Pole Sensor Circuit 11 Motor Driver 12 Diode Circuit 13 Rotation Speed Detection Means 14 Current Detection Means 15 Rotational Speed Computation means 16 Comparison determination means 17 Notification means 18 Comparator

Claims (1)

[Claims] 1. When the amount of air required for combustion in a burner of a combustion device is controlled by the value of current supplied to a motor in a combustion fan, the motor current value in the combustion fan is detected together with the number of revolutions for normal operation. Is compared with the permissible rotation speed of the motor corresponding to the current value in the above, and if the rotation speed of the motor is outside the permissible rotation speed, the combustion is interrupted or notified as an abnormal state occurrence. Operation control method for combustion equipment.