CN1164002A - Burner controller - Google Patents

Abstract

This invention provides a control device for combustion apparatus, which can surely detect the ignition even when it is used at a high altitude, or under a state wherein dust adheres to the air feeding passage for combustion. A control device for combustion apparatus is equipped with a timer unit 7b to output a signal when a specified period of time has passed after a start regarding the ignition motion, to a combustion control unit 7 which makes a combustion apparatus perform a combustion by controlling a combustion air feeding means 3 and a fuel feeding means 2, an air/fuel ratio setting unit 7a which sets an air/fuel ratio at the time of ignition to a value being different from an air/fuel ratio during a normal combustion, and an ignition air/fuel ratio changing means 7c which changes the air/fuel ratio by the air/fuel ratio setting unit 7a, at the point when earlier one of an ignition detecting signal or a signal from the timer unit 7b is input.

Description

Burner Controls

The present invention relates to a control device for a combustion appliance such as a hot air heater.

So far, in combustion appliances such as hot air heaters, during normal combustion, in order to suppress harmful gases emitted during combustion, the amount of combustion air and fuel is controlled to maintain an optimal combustion state. In the case of such a combustion appliance, the ratio (air-fuel ratio) between the optimum air volume and the combustion volume during normal combustion tends to increase during ignition, and the ignition performance is poor. Set it lower, and still control it according to normal combustion after ignition.

In addition, like the control device of the combustion appliance described in Japanese Patent Publication No. 6-29669, a plurality of ignition air volume-combustion volume setting sections are provided, and the air-fuel ratio different from that of normal combustion is set by the setting section. At the start of operation or after a predetermined time has elapsed from the start of operation, one of the above-mentioned air volume-combustion volume settings at ignition is selected based on the signal obtained from the temperature detection device for detecting the temperature of the combustion part.

In the case of this device, the optimum air-fuel ratio corresponding to the temperature of the combustion part is selected for ignition at the time of ignition, so even if the temperature of the combustion part changes from a cold state to a high temperature state at the time of re-ignition, optimum ignition can be obtained Under normal conditions, it will not cause unburned gas or yellow flame to burn when ignited.

However, in the above-mentioned prior structure, in order to improve the ignition performance under the normal use state, the air-fuel ratio at the time of ignition should be lowered in advance, for example, it is used in places with low air density such as plateau areas, or when dust and the like are attached to the combustion air. When the air is supplied to the passage and the air volume is reduced, the air-fuel ratio at the time of ignition becomes smaller, and as a result, a yellow flame appears at the time of ignition.

Usually, the ignition is detected by the magnitude of the flame current flowing through the flame, but when the yellow flame is ignited, the flame current is small, so the ignition is not detected, the safety device is activated, and the ignition operation is stopped, so that the combustion cannot continue.

Even if ignition is detected, since the air-fuel ratio of normal combustion is not reached until the specified time elapses, it continues to burn with a yellow flame during this period, and there are problems such as emission of harmful gas and foul smell.

The present invention was developed in order to eliminate the above-mentioned problems, and the purpose is to obtain such a control device for a combustion appliance that can be used not only in a normal use state, but also in high altitude areas or when dust is attached to the combustion air supply passage. Even under these conditions, fire detection can be reliably carried out and at the same time optimum combustion can be carried out.

The burner control device according to the present invention is composed of a combustion unit, a fuel supply unit for supplying fuel to the combustion unit, a combustion air supply unit for supplying combustion air to the combustion unit, and a control unit for controlling the combustion air supply unit and the fuel supply unit. A combustion control unit for combustion and an ignition detection device that outputs an ignition detection signal after a flame is formed in the combustion unit are configured. The above-mentioned combustion control unit is provided with a timer unit that starts in connection with the ignition operation and outputs a signal after a predetermined time elapses, an air-fuel ratio setting unit that sets the air-fuel ratio at the time of ignition to a value different from the air-fuel ratio at the time of normal combustion, and Ignition air-fuel ratio changing means for changing the air-fuel ratio at the time of ignition of the air-fuel ratio setting part at the timing of inputting the sooner of the ignition detection signal or the signal from the timer part.

The air-fuel ratio setting unit has a plurality of ignition air-fuel ratio levels, and the ignition air-fuel ratio changing device sequentially changes the air-fuel ratio according to the count value of the timer unit when the ignition detection signal is not input.

Fig. 1 is a block diagram of a control device for a combustion appliance in an embodiment of the present invention.

Fig. 2 is a structural diagram of a combustion appliance in an embodiment of the present invention.

Fig. 3 is a circuit diagram of a control device in an embodiment of the present invention.

Fig. 4 is a control flowchart of the control device in one embodiment of the present invention.

Fig. 5 is a control flowchart of the control device in the second embodiment of the present invention.

Figure 1: Combustion section

2: Combustion supply device (electromagnetic pump)

3: Combustion air supply device (combustion blower)

5: Fire detection device (flame detection rod)

7: Combustion Control Department

7a: Air-fuel ratio setting unit

7b: Timing Department

7c: Air-fuel ratio changing device during ignition

Example 1:

An embodiment of the present invention will be described below with reference to the block diagram of the control device in FIG. 1 and the structural diagram in FIG. 2 .

In Fig. 1 and Fig. 2, 1 is a combustion part, 2 is an electromagnetic pump as a fuel supply device for supplying fuel to the combustion part 1, and 3 is an air supply device for combustion as a combustion air supply to the above-mentioned combustion part 1. A blower for combustion, 4 is an igniter as an ignition device, and 5 is a flame detection rod as an ignition detection device for detecting a flame current flowing through the flame 6 .

7 is a combustion control section that controls the combustion of the electromagnetic pump 2, the combustion air blower 3, and the igniter 4. It is equipped with a ratio of the air volume for combustion to the combustion volume and controls the air-fuel ratio of the electromagnetic pump 2 and the combustion air blower 3. The setting unit 7a, the timer unit 7b that starts counting at the same time as the ignition operation is started, and the air-fuel ratio setting unit that changes the air-fuel ratio based on the earlier signal of the signal from the timer unit 7b and the signal from the flame detection lever 5 The ignition air-fuel ratio changing device 7c of the ignition air-fuel ratio of 7a starts the operation by the operation switch 8 .

The combustion unit 1 is composed of a burner head 1a for generating a flame 6, a vaporization unit 1b for vaporizing the liquid fuel, and a heater 1c for heating the vaporization unit 1b.

Fig. 3 is a circuit diagram of the above control device.

In Fig. 3, 9 is a commercial power supply, and 7 is a combustion control unit composed of a microcomputer, etc., and the combustion control unit 7 is connected to a relay coil 10a that is connected to a relay contact 10b that is energized to the heater 1c, and is connected to the igniter 4. The relay coil 11a of the energized relay contact 11b, the solid circuit relay (hereinafter referred to as SSR) 12 composed of a light-emitting element 12a and a photosensitive triac 12b for phase control of the combustion air blower 3, and a drive electromagnetic pump 2 13 with the drive.

The signals of the operation switch 8 and the flame detection rod 5 are input into the combustion control part 7 .

Next, the operation in the above configuration will be described with reference to the control flow chart in FIG. 4 .

First, after the operation switch 8 is turned on (step 20), the combustion control unit 7 energizes the relay coil 10a, closes the relay contact 10b, energizes the heater 1c, and starts preheating the gasification unit 1b (step 21). After the warm-up is over, the first ignition air-fuel ratio is set by the air-fuel ratio setting part 7a in the combustion control part 7 (step 22), and after the SSR12 is energized, the combustion blower 3 is rotated so as to reach the set air-fuel ratio (step 23). ), start to clean the furnace.

By changing the phase angle of SSR12, the blower 3 for combustion is controlled to reach the set speed. Usually, in order to improve the ignition performance, the air-fuel ratio at the time of ignition is set to be slightly smaller than that at the time of normal combustion. For example, the combustion rate during normal combustion is set to 2500Kcal/h, the rotational speed of the combustion air blower 3 is 1900 rpm, and the rotational speed of the combustion air blower 3 is set to only 1800 rpm during ignition. Alternatively, the rotation speed of the combustion blower 3 may be kept constant, and only the combustion amount may be changed.

After cleaning the furnace (step 24), the relay coil 11a is energized, the relay contact 11b is closed, the igniter 4 is connected, and the electromagnetic pump 2 is connected by the driver 13 at the same time, and the timing part 7b in the combustion control part 7 starts simultaneously. Count (step 25).

The electromagnetic pump 2 is turned on, and liquid fuel such as kerosene is supplied to the gasification part 1b and becomes gasification gas due to high temperature. When the gasification gas reaches the burner head 1a, it is ignited by the spark of the igniter 4.

After the flame 6 is generated, a flame current flowing through the burner head 1 a is formed from the flame detection rod 5 . The magnitude of the flame current varies with the air-fuel ratio. When the yellow flame burns or enhances the combustion, the flame current is smaller than that in the best combustion state.

When the flame current reaches a predetermined value or more, the combustion control unit 7 detects ignition (step 26), stops the energization of the relay 11a, and turns off the igniter 4 (step 27).

After the ignition is detected, the ignition air-fuel ratio changing device 7c in the combustion control section 7 sends a signal to the air-fuel ratio setting section 7a to set the second ignition air-fuel ratio (step 28), and the SSR12 performs phase control to change the combustion blower. 3 (step 29), for example, change from 1800rpm to 1850rpm.

After 30 seconds from the counted value of the timer unit 7b (step 30), the air-fuel ratio setting unit 7a changes to the set value during normal combustion (step 31), and the set rotation speed of the combustion blower 3 is changed from 1850rpm to 1900rpm.

In this way, the air-fuel ratio of the normal combustion is not set immediately after ignition, and the air-fuel ratio of the second ignition is temporarily used for combustion. Therefore, since the temperature of the combustion part 1 and the gasification gas is low immediately after ignition, even if the air-fuel ratio is slightly lowered, the combustion can be performed again. Gradually increasing the air-fuel ratio can also suppress yellow flame combustion when the speed changes.

Secondly, for example, when it is used in a plateau area or dust is attached to the combustion air supply passage, the air density or supply volume becomes small, so it is in a state of yellow flame combustion, and the flame current often does not reach the specified value. At this time, even if the timer started at the same time as the ignition action has not detected ignition (step 32), a signal is sent from the timing section 7b to the ignition air-fuel ratio changing device 7c, and the air-fuel ratio setting section The value of 7a is set as the second ignition air-fuel ratio (step 33), and the set rotation speed of the combustion blower 3 is changed from 1800 rpm to 1850 rpm (step 24).

When the rotation speed of the combustion blower 3 rises, the air shortage is eliminated, the combustion state becomes optimal, and the flame current reaches a predetermined value or more, enabling ignition detection. After ignition is detected, it goes to step 27 the same as the above flow, but since steps 28 and 29 have already been executed, it goes to steps 30 and 31.

In this way, in this embodiment, not only under normal use conditions, but also in high altitude areas, or when dust is attached to the combustion air supply passage and the air supply amount is slightly insufficient, because the air-fuel ratio is changed when the ignition is not fired. It is ignited in the best combustion state, so it can be detected reliably, and it will not continue to burn with a yellow flame to emit harmful gases, nor will it emit a foul smell.

Example 2:

In Embodiment 1 above, when ignition is not detected, the ignition air-fuel ratio is changed only once, but as shown in the control flow chart in FIG. 5 , the ignition air-fuel ratio may be changed sequentially before ignition is detected.

In FIG. 5, steps 20 to 31 are the same as those in FIG. 4, and the description thereof is omitted.

When no ignition is detected, the timer enters steps 36 and 37 every multiple of 5 (step 35), that is, 5, 10, 15, ... seconds, and changes the air-fuel ratio during ignition of the air-fuel ratio setting part 7a to make the combustion Use the rotating speed of blower 3 to increase 50rpm every time.

Therefore, the air-fuel ratio at the time of ignition is quite low, and even if the ignition is in a red fire state, the ignition air-fuel ratio is gradually changed until the optimum combustion state where the flame current rises is reached, so the ignition can be reliably detected.

Claims (2)

1. burner controller, it is characterized in that, it is by burning portion, fuel is supplied with the fuel supply system of this burning portion, supply with the combustion air feedway of combustion air to above-mentioned burning portion, control the burning control part that this combustion air feedway and above-mentioned fuel supply system burn, and the catch fire checkout gear that catches fire of detection signal of output constitutes after above-mentioned burning portion forms flame, have and the light a fire action associated ground starting and through the timing portion of output signal after the stipulated time of above-mentioned burning control part, the air-fuel ratio configuration part of the value that the air-fuel ratio the when air-fuel ratio during with igniting is set at normal combustion is different, and imported from the signal of above-mentioned catch fire detection signal or above-mentioned timing portion come among both the igniting air-fuel ratio change device of moment of signal soon air-fuel ratio when changing the igniting of above-mentioned air-fuel ratio configuration part.

2. the described burner controller of claim 1, it is characterized in that, air-fuel ratio when there is the igniting of a plurality of class above-mentioned air-fuel ratio configuration part, above-mentioned igniting air-fuel ratio change device is not when detection signal is caught fire in input, count value according to above-mentioned timing portion changes air-fuel ratio successively.

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