KR20000056269A - Method and apparatus for controlling combustion of gas heater - Google Patents

Abstract

PURPOSE: A method and apparatus for controlling combustion of gas heater are provided to reduce incomplete combustion gas caused by unstable combustion flame. CONSTITUTION: In a method and apparatus for controlling combustion of gas heater, the apparatus comprises a first flame detecting member(100) for detecting a flame at a first desired position in a combustion chamber and then outputting a first desired control signal according to the state of the flame in the first position; a second flame detecting member(100') for detecting a flame at a second position except for the first position in the combustion chamber and then outputting a second desired control signal according to the state of the flame in the second position; a microcomputer(300) for receiving the first and second control signals, detecting whether the combustion of the flame is stable or not, and then outputting a fan speed control signal and a valve control signal; a fan speed control unit(401) for receiving the fan speed control signal output from the microcomputer(300) and then controlling the rotational speed of a fan for combustion; and a gas valve control unit(402) for receiving the valve control signal output from the microcomputer(300) and then controlling the valve for supplying combustion gas. Accordingly, since the combustion flame is detected by two flame detecting rods(100, 100') and the stability of the combustion flame is determined according to the combustion flame detected in the respective flame detecting rods(100, 100'), generation of incomplete combustion gas caused by unstable combustion flame is reduced in the gas heater.

Description

Method and device for controlling combustion of gas heaters {Method and Apparatus for controlling combustion of Gas Heater}

The present invention relates to a gas heater, and more particularly, to a combustion control method and apparatus for a gas heater.

In general, gas heaters are heated with gas as fuel. A gas heater burns gas and heats the room by converting cold air into hot air by using combustion heat generated by the combustion of the gas.

1 is a perspective view showing the front of a general gas heater. 2 is a block diagram showing the internal structure of a gas heater according to the prior art.

The conventional gas heater has a main body 1, a fan housing 2 fixed to the lower part of the main body, a blowing fan 3 installed in the fan housing to generate a blowing force by rotation of the motor, and a lower part of the front surface of the main body. A suction grill 4 installed to suck air into the main body according to the rotation of the blower fan 3, and a barrier 5 fixed to one side of the upper part of the fan housing 2 to support various components into the main body 1; And a combustion chamber 6 fixed above the blower fan 3 to burn the mixed gas of gas fuel and air, a burner 7 for igniting the mixed gas, and a gas fuel supplied into the burner 7. A gas supply pipe 8, an intake pipe 9 which is fixed to a wall of the room and has a suction hole formed to the outside to suck in air necessary for combustion, and one end is connected to the indoor side of the intake pipe 9, and the other end is burner (7) connected to the burner (7) to supply the combustion air sucked through the intake pipe (9) Air supply pipe (10), air inlet fan (11) is provided in the connection portion between the air supply pipe (10) and the burner (7) to provide the suction force to suck the combustion air, and the gas supply pipe (8) A gas valve 12 for selectively opening and closing the heat exchanger, a heat exchanger 13 connected to an upper portion of the combustion chamber 6 and heat-exchanging cold air sucked into the main body 1 with hot air by combustion heat, and a heat exchanger A gas discharge pipe 14 connected to one side of the 13 and exhausting the combustion gas heat-exchanged with cold air to the outside while the other end penetrates the intake pipe 9 and the front of the main body 1 A discharge grill 15 installed at an upper portion and discharging hot air heat-exchanged by the heat exchanger 13 to the outside of the main body 1, and a control unit 16 equipped with a barrier 5 to control the operation of the device as a whole. And an indoor temperature sensor (17) mounted at the top of the blowing fan (3) to detect the indoor temperature. It is made.

Referring to the operation of the gas heater configured as described above are as follows.

When the user selects the heating mode provided in the front mode selection unit of the main body 1, the control of the control unit 16, the air suction fan 11 installed in the connection portion of the air supply pipe 10 is mounted to the barrier (5) Rotate by receiving signal. At this time, the outside air is sucked into the intake pipe 9 through the suction hole of the intake pipe 9 and then supplied to the burner 7 through the air supply pipe 10.

The air supplied to the burner 7 flows into the combustion chamber 6 through the slit hole formed in the burner 7 while the rotation of the air suction fan 11 continues. In addition, the air introduced into the combustion chamber 6 performs a prepurge process that passes through the heat exchanger 13 to the outside through the gas discharge pipe 14 for a predetermined time. The pre-purging process is performed for a predetermined time to completely prevent the explosion risk of the combustion chamber 6 due to the remaining gas during initial combustion by completely discharging the gas remaining in the combustion chamber 6 to the outside.

After the pre-purging process is performed as described above, since the air suction fan 11 continues to rotate, combustion air is sucked into the intake pipe 9 through the suction hole 9a formed in the intake pipe 9. It is supplied to the burner 7 through the air supply pipe (10). Moreover, since the gas valve 12 provided in the gas supply pipe 8 is opened and closed by receiving the control signal of the control part 16, gas fuel is supplied to the burner 7, and this gas is blown out through a nozzle (not shown). Then, it is loaded into the combustion air and injected into the combustion chamber 6 through a slit hole (not shown) formed in the burner 7. At this time, the ignition means (not shown) operates to ignite the flame in the mixed gas of the gas and the combustion air, whereby the mixed gas is combusted in the combustion chamber 6.

When the mixed gas is combusted in the combustion chamber 6, combustion heat is generated, and this combustion heat is heated outdoors while moving the heat exchanger 13 connected to the upper part of the combustion chamber 6 from the lower part to the upper part and then outdoor through the gas discharge pipe 14. To be discharged.

At this time, since the gas discharge pipe 14 maintains a high temperature by the heat of combustion discharged, the combustion air sucked into the intake pipe 9 through the suction hole formed in the intake pipe 9 in the above-described operation is heat-exchanged and fixed. It rises above the temperature. As a result, the combustion air heat-exchanged at high temperature is continuously supplied to the burner 7 through the air supply pipe 10.

When the gas fuel is combusted in the combustion chamber 6, the blowing fan 3 in the fan housing 2 fixed in the main body 1 rotates under the driving force of the motor under the control of the control unit 16, so that the blowing fan ( Blowing power is generated in 3). Then, the air in the room is sucked into the interior through the suction grille 4 and then moved upward in the main body 1 as the blower fan 3 continues to rotate. At this time, the moving air is heat-exchanged by the heat of combustion as it passes through the heat exchanger 13 to be changed into hot air, and the hot air is discharged into the room through the discharge grill 15 provided at the upper front of the main body 1. In other words, the gas heater is heating.

In addition, the gas heater continues the combustion to drive the blower fan 3 when the room temperature detected by the room temperature sensor 17 is lower than or equal to the desired temperature, and terminates the combustion fan when the room temperature is higher than the desired temperature. (3) is stopped.

The conventional gas heater detects the flame (salt) of the combustion chamber as shown in FIG. 3 and inspects the combustion chamber state. 4 is a circuit diagram illustrating in detail the dye detection circuit 16 ″ of FIG. 3. At this time, the combustion chamber of the gas heater is provided with a salt sensing rod (6 ') that can detect the flame.

When the salt sensing rod 6 'contacts the flame, the salt sensing rod 6' applies a current generated by the ions included in the flame to the salt detection circuit 16 ''. The salt detection circuit 16 ″ receives a current generated from the salt detection rod 6 ′ and applies a predetermined voltage pulse P _A to the microcomputer 16 ′. The microcomputer 16 'grasps the combustion state of the combustion chamber by the voltage pulse of the salt detection circuit 16''.

The salt detection circuit 16 '' is configured as shown in FIG. When the flame contacts the dye-sensing rod 6 ', a predetermined current is applied to the base terminal of the transistor FET so that the voltage pulse P _A is input to the microcomputer 16'.

However, the conventional combustion control device provided with the salt detection circuit 16 '' has the following problems.

The voltage pulse P _A applied by the conventional salt detection circuit 16 ″ to the microcomputer 16 ′ is as shown in FIG. 5. That is, when a voltage of a range in which the transistor is conductive is input to the base terminal of the transistor, the transistor is always in a conductive state regardless of the voltage level. Thus, a voltage pulse P _A as shown in FIG. 6 is applied to the microcomputer. However, even when the level of the voltage input to the base terminal becomes unstable after the transistor is turned on, the conventional salt detection circuit still applies the same pulse to the microcomputer. As a result, even if the flame state of the combustion chamber becomes unstable, the conventional gas heater supplies the fuel gas and the air of the same pressure, there is a problem that the abnormal combustion section that generates a large number of toxic gases such as carbon monoxide.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a combustion control device of a gas heater equipped with a flame detection circuit capable of detecting abnormal combustion sections and a combustion control method capable of detecting abnormal combustion sections. have.

1 is a perspective view showing the front of a typical gas heater.

Figure 2 is a block diagram showing the internal structure of a gas heater according to the prior art.

3 is a view illustrating a microcomputer of a flame detection circuit and a gas heater for detecting a flame in a combustion chamber in a conventional gas heater.

4 is a circuit diagram showing in detail the salt detection circuit shown in FIG.

FIG. 5 is a waveform diagram showing an input voltage applied to a transistor of the salt detection circuit shown in FIG.

FIG. 6 is a waveform diagram illustrating a control signal applied to a microcomputer by an input voltage of the transistor illustrated in FIG. 6.

7 is a block diagram schematically illustrating the components of the present invention.

8 is a circuit diagram showing in detail the components of the present invention shown in FIG.

FIG. 9 is a waveform diagram showing an input voltage applied to the transistor of the present invention shown in FIG. 7 and a control signal applied to a microcomputer.

10 is a flowchart illustrating a method of determining the unstable combustion of the combustion chamber of the microcomputer of the present invention.

Explanation of symbols for main parts of the drawings

100: salt detection rod of the first salt detection unit 100 ': salt detection rod of the second salt detection unit

200: first salt detection unit 200 ': second salt detection unit

300: microcomputer 400: air-fuel ratio control circuit

401: fan motor control circuit 402: gas valve control circuit

410: fan motor 420: gas valve

The present invention is characterized by the detection of the abnormal combustion section according to the output state of the salt detection circuit by installing two or more salt sensing rods in the combustion chamber to more accurately detect the flame state than conventional.

As illustrated in FIG. 7, the first flame detection unit 200 detects a flame at a predetermined first position in a combustion chamber and outputs a predetermined first control signal P _A according to the flame state at the first position. ), The second flame detection unit 200 ′, which detects the flame at the second position except the first position in the combustion chamber and outputs a predetermined second control signal P _B according to the flame state at the second position. The control signal output from the microcomputer 300 and the microcomputer 300 that detects whether the combustion of the flame becomes unstable by receiving the control signal P _A and the second control signal P _B and outputs the control signal. It is configured to include an air-fuel ratio control device 400 for receiving the input to adjust the air mixing ratio of the combustion chamber.

The first flame detection unit 200 detects a flame that is burned in the combustion chamber and outputs a predetermined first control signal P _A. The second salt detection unit 200 ′ detects a flame at a position different from that detected by the first salt detection unit 200, and outputs a predetermined second control signal P _B. That is, the position of the flame detected by the first salt detection unit 200 and the position of the flame detected by the second salt detection unit 200 'are different.

Both the first salt detection unit 200 and the second salt detection unit 200 ′ receive a salt sensing rod for generating a predetermined electrical signal according to a flame state, and an electric signal generated from the salt sensing rod for first control. It consists of a dye-sensing circuit which outputs the signal P _A. The salt detection rod 100 of the first salt detection unit 200 and the salt detection rod 100 'of the second salt detection unit 200' are installed at different positions in the combustion chamber to detect the state of the combustion chamber flame. The salt detection circuit provided in both the first salt detection unit 200 and the second salt detection unit 200 'is the same as the salt detection circuit installed in the conventional gas heater.

The microcomputer 300 receives the first control signal P _A and the second control signal P _B to detect whether the combustion of the flame becomes unstable. Thus, the microcomputer 300 outputs a control signal for controlling the rotational speed of the combustion fan 410 of the gas heater and the opening and closing of the gas valve 420 according to the combustion state of the flame.

The air-fuel ratio control apparatus 400 receives the fan speed control signal as shown in FIG. 8 and controls the rotational speed of the combustion fan 410 and the valve control output from the microcomputer 300. It is composed of a gas valve control unit 402 for adjusting the valve 420 for supplying the combustion gas by receiving a signal.

The fan speed controller 401 receives a control signal output from the microcomputer 300 to adjust the rotational speed of the combustion fan 410 of the gas heater, and the gas valve controller 402 controls the microcomputer 300. The valve receives the signal to control the valve 420 for supplying the combustion gas of the gas heater.

At this time, according to the operation of the present invention, the microcomputer 300 receives the first control signal P _A and the second control signal P _B to determine the flame state in the combustion chamber as follows. FIG. 9 shows waveforms of input voltages of the transistors FET1 and FET2 provided in each of the dye sensing circuits, and the first control signal P _A and the second control signal P _B output accordingly.

If no spark is generated in the combustion chamber, the input voltage of each FET maintains a potential of 0 volts, as shown in FIG. 9, so that both the first control signal P _A and the second control signal P _B are both Keep low. At this time, when the flame is ignited in the combustion chamber of the gas heater and combustion is normally performed, the salt detection rod 100 of the first salt detection unit 200 and the salt detection rod 100 'of the second salt detection unit 200' are disposed. All electrical states change, so the input voltage of each FET changes. As a result, the first control signal P _A and the second control signal P _B become high.

If the flame in the combustion chamber becomes unstable momentarily, either the first control signal P _A or the second control signal P _B becomes low. The flame of the combustion chamber, which is normally burned, contacts both the salt detection rod 100 of the first salt detection unit 200 and the salt detection rod 100 'of the second salt detection unit 200', and thus, the first control signal P _A. ) And the second control signal (P _B ) are both high, but the reason why any one of the first control signal (P _A ) or the second control signal (P _B ) is low (low combustion chamber) This is because the flame does not come into contact with any one of the salt detection rods 100 of the first salt detection unit 200 and the salt detection rods 100 'of the second salt detection unit 200'.

The control signal, which has been low, is changed high again. The reason is that the flame in the unstable combustion chamber does not stably contact the salt sensing rod. At this time, the microcomputer 300 detects the instability of the first control signal P _A and the second control signal P _B to determine whether the flame is stable, and the fan motor control signal suitable for the current flame state. Output the valve control signal.

The fan motor control signal output from the microcomputer 300 controls the fan motor of the gas heater to reduce the inflow of air to reduce the incombustible gas such as carbon monoxide generated by the unstable flame of the combustion chamber. The valve control signal output from the microcomputer 300 controls the opening and closing of the gas valve 420 of the gas heater in order to stabilize the unstable flame of the combustion chamber.

The method of determining whether the flame is stable by detecting the states of the first control signal P _A and the second control signal P _{B by} the microcomputer 300 according to the present invention is the flowchart shown in FIG. 10.

First, if the first control signal P _A and the second control signal P _B are both high (S10, S20), the microcomputer 300 of the present invention initializes a predetermined waiting time (S21). . If the first control signal P _A and the second control signal P _B are both low despite the current ignition, the present invention determines that an error has occurred in the combustion chamber (S11). In addition, when any one of the first control signal P _A and the second control signal P _B is low and one is high, the present invention relates to the first control signal P _A. The waiting time after any one of the second control signals P _B becomes low (S30). Thus, if the waiting time passes for a predetermined time, the fan speed is reduced until the control signal of the low becomes high again (S40) to reduce the amount of air supplied to the combustion chamber. Further, even when the fan speed is decelerated to a predetermined level or less (S51), if the control signal to be low does not become high again (S50, S52), the microcomputer 300 of the present invention is a gas valve ( By controlling the opening and closing of 420 (S53 and S55), the flow rate of the fuel gas supplied to the combustion chamber is controlled until the control signal of the low level becomes high again (S54 and S56).

Thus, when the low control signal becomes high again, the waiting time t1 is initialized again (S60), and it is determined whether the combustion section ends (S70). Then, the microcomputer 300 of the present invention adjusts the combustion flame by sensing the phases of the first control signal P _A and the second control signal P _B until the combustion of the gas heater is completed.

Unlike the conventional gas heater combustion control circuit, the present invention senses a combustion flame by two salt sensing rods and determines the instability of the combustion flame according to the combustion flame detected in each salt sensing rod. There is an effect of reducing the occurrence of incombustible gas by the unstable combustion flame that was generated.

Claims (3)

A first flame detection unit detecting a flame at a predetermined first position in the combustion chamber and outputting a predetermined first control signal according to the flame state at the first position; A second flame detection unit detecting the flame at a second position except the first position in the combustion chamber and outputting a predetermined second control signal according to the flame state at the second position; A microcomputer that receives the first control signal and the second control signal and detects whether combustion of the flame becomes unstable and outputs a fan speed control signal and a valve control signal; A fan speed control unit which receives the fan speed control signal output from the micom and controls a rotation speed of a combustion fan; and And a gas valve control unit configured to control a valve for supplying combustion gas by receiving the valve control signal output from the microcomputer. The method of claim 1, wherein the first salt detection unit A dye-sensing rod for generating a predetermined electrical signal according to the state of the flame, Combustion control device for a gas heater, characterized in that consisting of a salt detection circuit for outputting the first control signal by receiving the electrical signal generated from the salt-sensing rod. The method of claim 1, wherein the second salt detection unit A dye-sensing rod for generating a predetermined electrical signal according to the state of the flame, Combustion control device for a gas heater characterized in that it consists of a dye detection circuit for outputting the second control signal by receiving the electrical signal generated from the salt sensing rod.