JPH0894069A - Gas combustion device - Google Patents

Abstract

PURPOSE: To stabilize an unstable flame by a method wherein at an initial stage, control is effected so that a gas amount is adjusted to a value lower than a gas amount corresponding to an air flow expected by the number of revolutions of a fan and when ignition is detected, transfer to a subsequent stage is effected and a feed gas amount is increased to a value higher than that at the initial stage. CONSTITUTION: An ignition control executing means 61 for a gas combustion device controls drive of a fan 12 at the number of revolutions lower than that during ordinary control and by operating an igniter 40, a burner 21 is ignited. By detecting ignition of the burner 21, a gas feed amount of a gas feed means 30 is controlled. In this case, further, a gas feed control means is provided and at an initial stage, a feed gas amount is controlled so that a gas amount is adjusted to a value lower than a gas amount corresponding to an air flow expected by the number of revolutions of a fan. When ignition is not detected, (even when ignition is detected), transfer to a subsequent stage is effected along with a lapse of time and prior to fn control or gap feed control a feed gas amount is increased to a value higher than that at the initial stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas combustion device, and more particularly to gas supply control during ignition.

[0002]

2. Description of the Related Art A conventional gas hot water supply device (gas combustion device)
Is a water pipe, a heat exchanger leading to the water pipe, a gas burner for heating the heat exchanger, a gas supply means for supplying gas to the gas burner, and a fan for supplying air to the gas burner,
An igniter for igniting the gas burner and a duct for exhausting exhaust gas are provided. Further, the gas hot water supply device has an ignition control execution means for controlling ignition to the gas burner, and a normal control execution means for executing gas control and air volume control for hot water discharge after ignition. This ignition control execution means,
Fan control means for controlling the fan at a lower rotation speed than during normal control, igniter control means for activating the igniter to ignite the gas burner, ignition detection means for detecting ignition to the gas burner, and normal control A gas supply control means is provided for controlling the gas supply means so as to supply a predetermined amount of gas, which is much smaller than the predetermined time, to the gas burner for a predetermined time. By the way, when the hot water supply device is ignited, it is necessary to properly balance the amount of air supplied to the gas burner and the amount of gas (so-called air-fuel ratio). Otherwise, it will not ignite, the ignition will be unstable even if ignited, or conversely, it will explode.

However, it has been difficult to control to an appropriate air-fuel ratio as described above. The reason will be described in detail with reference to FIGS. FIG. 9 shows an airtight house such as an apartment. In addition to the hot water supply device G, a gas range R is installed in this house. As described above, the gas hot water supply device G includes the gas burner 21, the heat exchanger 22, the fan 12, and the like, and the duct 1 communicating with the outside of the house.
Equipped with 3. A range hood H is arranged above the gas range R, and a ventilation fan V is provided in the range hood H. When the ventilation fan V is not turned, the room atmospheric pressure is atmospheric pressure. At this time, the ignition control execution means causes the fan 12 to rotate at a predetermined rotation speed, and the gas burner 2
Supply air to 1. In addition, at room atmospheric pressure, the fan 12
Letting W2 be the amount of air supplied to the gas burner 21 that is expected by rotating at a predetermined number of revolutions, the gas supply means is controlled such that the amount of gas Q2 that allows appropriate ignition with this amount of air W2. In this case, stable ignition can be performed at the optimum air-fuel ratio. On the other hand, when the ventilation fan V is turned, the room air is discharged from the range hood H of the kitchen as shown by the arrow A, and the entire room becomes negative pressure. However, since the rotation speed of the fan 12 does not change, the air volume actually supplied to the gas burner 21 decreases according to its negative pressure. The amount of air supplied to the gas burner 21 is also reduced due to the blowing of strong air into the duct 13 and the increase in flow resistance due to the attachment of soot on the heat exchanger 22. If the air volume at this time is W1, the air volume W1
The air-fuel ratio of the above gas amount Q2 with respect to is higher than the optimum air-fuel ratio. In this case, explosive ignition can occur.

This situation will be described in more detail with reference to FIG. FIG. 10 shows an ignition limit curve L1 shown by a solid line.
An ignition possible region Z sandwiched between the (lower limit) and the ignition limit curve L2 (upper limit) is shown. It should be noted that, on the left side of the lower limit L1 of the ignitable region Z, the amount of gas is too small with respect to the air volume to cause ignition, and on the right side of the upper limit L2, the gas amount is too large with respect to the air volume and ignition does not occur. When the ventilation fan V is not turned on, that is, when the supply gas amount Q2 is the air amount W2 corresponding to the atmospheric pressure in the room, the intersection C2 is the ignition limit curve L.
It is on the right of 1 and on the left of the ignition limit curve L2. In other words, it belongs to the ignitable region Z, stable ignition is possible with the balance of the supply air amount and the gas amount, and the ignition state is also stable. However, as described above, the ventilation fan V
When is turned, the air volume is reduced to W1. In this case, the intersection C2 is the intersection C3 between the air volume W1 and the gas volume Q2.
Shift to Since the intersection C3 is slightly on the right side of the ignition limit curve L2, the ignition is not normally performed. When this non-ignition state continues, the combustion chamber is located on the left side of the ignition limit curve L2 (belonging to the ignition possible zone Z) in which the mixed gas on the right side of the burner L2 and the air supplied from between the burners are mixed. Unburned gas accumulates. At that time, if the ratio of air to gas near the igniter slightly fluctuates and accidentally enters the ignitable region Z, ignition occurs. At the time of this ignition, the unburned gas accumulated in the combustion chamber is also ignited at once, so explosive ignition occurs.

In order to avoid the danger of explosive ignition, gas supply control means has been developed for controlling the gas amount in two stages, an initial stage and a next stage. That is, in the initial stage of the ignition control, the gas supply control means supplies the gas amount with a smaller first gas amount Q1 so as not to perform explosive ignition with the air amount W1. In the case of the above-mentioned indoor negative pressure, the intersection C1 of the air volume W1 and the gas volume Q1 enters the ignitable region Z, so that ignition is performed. However, in the case of indoor atmospheric pressure, the air volume W2 and the gas volume Q
The intersection C4 of 1 does not enter the ignitable region Z (the air-fuel ratio is too thin), so ignition is not performed. When the ignition is not performed in the initial stage due to the atmospheric pressure in the room, the process proceeds to the next stage after a predetermined time has elapsed. In the next stage, the supply gas amount is increased to the second gas amount Q2 corresponding to the atmospheric pressure. In this way, ignition is performed in either of the intersections C1 and C2 while avoiding ignition in the explosion ignition situation (corresponding to the intersection C3).

[0006]

By the way, in the conventional apparatus, when the ignition is confirmed regardless of the initial stage or the next stage, the normal control execution means is used after maintaining the gas supply amount at the time of ignition for a predetermined time. Since the control is shifted to the normal control, there are inconveniences described below. The ignitable region Z changes depending on the type of gas. For example, for a gas of a low concentration that is difficult to ignite, ignition is performed within an ignitable region Z ′ sandwiched between the dotted lines L1 ′ and L2 ′, and for a gas of a type that easily ignites at a low concentration, dotted lines L1 ″, L2. Ignition is performed within the ignitable region Z ″ sandwiched by ″. In the case of a gas of a low concentration that is easily ignited in which the ignitable region is Z ″, the first gas is generated even when the indoor pressure is atmospheric pressure, that is, the supply air volume W2.
There was a case where ignition was performed with the gas amount Q1. That is,
Since the intersection C4 of the gas amount Q1 and the air amount W2 is located on the left of the ignition limit curve L1 described above, it does not enter the ignitable region Z in the case of normal gas, but it is slightly on the right side of the ignition limit curve L1 ″. Since it is located, it enters the ignitable region Z ″ in the case of a type of gas that is easy to ignite. The ignitable region also changes depending on the type of igniter and the installation state of the duct 13, and the same phenomenon occurs. The ignition in the vicinity of the ignition limit curve L1 ″ is an ignition in a state where the gas amount is small with respect to the air flow amount (a state where the air-fuel ratio is thin), and the flame after ignition is jumpy and unstable. . In general, once ignited, the gas burner 21 is heated by the flame and the gas temperature rises, and the flammable range of the gas spreads. However, if the flame jumps, the gas burner 21 is not heated and the flammable range of the gas is Does not spread. As a result, the flame continues to fly and is unstable, and as a result, the flame of the gas burner 21 once ignited may be extinguished without being able to withstand the rapidly increasing air volume when shifting to normal control.

[0007]

The subject matter of claim 1 of the present invention is, as shown in FIG. 1, a burner 1, gas supply means 2 for supplying gas to the burner 1, and indoor air to the burner 1. Fan 3 and an igniter 4 that ignites the burner 1,
In a gas combustion apparatus provided with ignition control execution means 5 and normal control execution means 6 for controlling air supply by the fan 3 and gas supply by the gas supply means 2 after ignition control,
The ignition control execution means 5 includes a fan control means 7 for controlling the fan 3 at a lower rotation speed than that in normal control, an igniter control means 8 for operating the igniter 4 to ignite the burner 1, and the burner. Ignition detecting means 9 for detecting ignition to 1 and the gas supply means 2 are controlled to control the gas supply amount at the time of ignition.
In the initial stage, the supply gas amount is controlled so that the gas amount is lower than the gas amount corresponding to the air flow rate expected by the fan rotation speed, and if ignition is not detected by the ignition detecting means 9 in this initial stage, time elapses. Accordingly, even if ignition is detected by the ignition detecting means 9 in the initial stage, the process proceeds to the next stage, in which the fan control and the gas supply control by the normal control executing means 6 are performed. And a gas supply control means 10 for increasing the supply gas amount from the initial stage prior to the above. According to a second aspect of the present invention, the gas supply control means performs the gas supply control in the next stage for a predetermined time, and further shifts from the initial stage to the next stage at the ignition detection time point. According to another aspect of the present invention, the fan control means controls the fan at a predetermined rotation speed, and the gas supply control means has a predetermined gas quantity lower than a gas quantity corresponding to an air volume expected by the predetermined fan rotation speed in the initial stage. If the ignition is not detected by the ignition detecting means for another predetermined time in the gas supply state with this first gas amount, the process shifts to the next stage when another predetermined time elapses. The supply gas amount is immediately increased to a predetermined second gas amount corresponding to the expected air flow rate by the predetermined fan rotation speed, and ignition is detected by the ignition detection means in the gas supply state at the first gas amount. When I did,
The present invention is characterized in that the supply gas amount is increased to the second gas amount immediately by moving to the next stage. According to a fourth aspect of the present invention, the gas supply control means gradually increases the supply gas amount to a predetermined gas amount over time in the next stage. According to a fifth aspect of the present invention, the gas supply control means gradually increases the supply gas amount in the initial stage.

[0008]

According to the present invention, in the ignition control, the supply gas amount is controlled so that the gas amount becomes lower than the gas amount corresponding to the air amount expected by the fan rotation speed in the initial stage, and when ignition is detected, it is necessary. Transition to the next stage and increase the amount of supply gas from the initial stage. As a result, even when ignition is performed in a state where the air-fuel ratio is thin, it is possible to shift to an appropriate air-fuel ratio, and it is possible to stabilize a flaky and unstable flame. According to the second aspect, since the gas supply control in the next stage is performed for a predetermined time, the flame can be stabilized. Further, since the transition from the initial stage to the next stage is performed at the time of ignition detection, the time required for ignition control can be shortened. In the third aspect, when ignition is detected in the gas supply state with the first gas amount, the process immediately proceeds to the next stage and the supply gas amount is increased to the second gas amount. This allows
It is possible to immediately shift the unstable flame in the first gas amount supply state to a stable flame. In claim 4,
In the next stage, the supply gas amount is gradually increased to a predetermined gas amount over time. As a result, the amount of gas does not suddenly increase, so that the generation of unburned gas and soot can be suppressed. According to the fifth aspect, the supply gas amount gradually increases in the initial stage. As a result, the amount of gas supplied to the burner before ignition can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a schematic configuration of a gas hot water supply device (gas combustion device). Reference numeral 11 is a casing of the hot water supply device. A fan 12 is connected to the lower end of the casing 11 and an exhaust duct 13 is connected to the upper end of the casing 11. A plurality of gas burners 21 (burners) are arranged in the lower part of the casing 11, and a heat exchanger 22 receives combustion heat from the gas burner 21 in the upper part of the casing 11.
Are arranged. A water pipe 24 passes through the heat exchanger 22. A flow sensor 25, a water temperature sensor 26, and a water amount control valve 27 are provided near the inlet 24a of the water distribution pipe 24.
And are installed. The water from the inlet portion 24a of the water distribution pipe 24 is heated when passing through the heat exchanger 22, and the hot water tap 2
Go to 4b. On the downstream side of the heat exchanger 22, a hot water outlet temperature sensor 28 is installed in the water distribution pipe 24.

Next, the gas supply means 30 for supplying gas to the gas burner 21 will be described. The gas supply means 30 has a gas pipe 31 leading to the gas burner 21. The gas pipe 31 is provided with an electromagnetic opening / closing valve 32 and a pressure proportional control valve 33 in order from the upstream side. A nozzle 34 is connected to the downstream end of the gas pipe 31. The gas burner 21 includes the gas from the nozzle 34 and the fan 12
The air from is introduced and mixed, and it blows out from the flame port on the upper surface and becomes a flame. An igniter 40 for ignition and a frame rod electrode 50 (ignition detection means) for detecting the ignition are installed above the gas burner 21. The detection signals from the various sensors 25, 26, 28, 50 and the like and the set temperature information from the temperature setter (not shown) installed in the remote controller (not shown) and the like are the control unit 60 provided in the casing 11. Is input to the microcomputer 61.

Next, air volume control and gas supply control by the microcomputer 61 will be described with reference to FIGS. The microcomputer 61 has a flow sensor 25.
In response to the water flow detection in step 1, the fan 12 is first rotationally controlled so as to have a predetermined rotational speed lower than that in the normal control. For a predetermined time t from the start of fan control, pre-purge for discharging unburned gas that may remain in the casing 11 is executed prior to ignition control. After executing prepurge,
Ignition control is performed. That is, while maintaining the fan 12 at a predetermined rotation speed, the electromagnetic opening / closing valve 32 is opened to supply the gas.
Moreover, by controlling the opening of the proportional control valve 33, the gas amount is controlled in two stages, the initial stage and the next stage. In this gas supply state, the igniter 40 is turned on to perform discharge. After the ignition of the gas burner 21 is detected by the frame rod electrode 50, the ignition of T0 is stabilized for a predetermined time, and the normal control is performed.

The gas amount control in the above two steps will be described in detail below. In this description, the terms and reference numerals described with reference to FIGS. The microcomputer 61 sets the supply gas amount to a predetermined first gas amount Q1 at the initial stage of ignition control. When the ventilating fan V is not turned on, the indoor air pressure is atmospheric pressure, so the air volume supplied to the gas burner 21 is W2 as shown in FIG. In this case, as shown in FIG. 10, since the intersection C4 of the gas amount Q1 and the air amount W2 does not belong to the ignitable region Z, the igniter 4
The gas burner 21 is not ignited even if discharge is performed at zero. Therefore, the ignition of the gas burner 21 is not detected by the frame rod electrode 50, and the microcomputer 61 shifts to the gas control in the next stage after the elapse of the predetermined time T1. In this next stage, a predetermined second gas amount Q2
Gas is supplied at (corresponding to intersection C2 in FIG. 10). Intersection C
Reference numeral 2 belongs to the ignitable region Z, and since an appropriate air-fuel ratio is achieved as described above, ignition is performed. After this ignition is detected, the ignition is maintained for a predetermined time T0 (another predetermined time), and the control is shifted to the normal control.

When the ventilation fan V is being turned, the indoor air pressure is in a negative pressure state, so that the air volume is W1 as shown by the solid line in FIG.
And less. Supply air volume W1 and supply gas volume Q1 at this time
At the intersection C1 corresponding to the above, since it belongs to the ignitable region regardless of the type of gas, it is possible to ignite in the initial stage. In this case, as shown in FIG. 4, the microcomputer 61 immediately shifts to the next stage at the time of detection of ignition and changes the gas amount from the first gas amount Q1 to the second gas amount Q2 (corresponding to the intersection C3 in FIG. 10). , And the gas supply state is maintained for a predetermined time T0. Even if the amount of gas is increased and the intersection point C1 is changed to the intersection point C3 as described above, explosion ignition is not caused because combustion has already been performed by the ignition before the shift. Further, once the fire is generated at the intersection C1, the gas burner 21 is heated by the stable flame and the combustible range of the gas is expanded. Therefore, even if the gas is shifted to the intersection C3, the gas is too rich and does not disappear, and the combustion continues normally.

By the way, in the case of a gas of a low concentration and which is easily ignited, the above-mentioned first gas is generated in the initial stage even when the indoor pressure is atmospheric pressure, that is, the supply air volume W2 (shown by an imaginary line in FIG. 4). There is a case where ignition is performed with one gas amount Q1 (that is, the intersection C4 of the air amount W2 and the gas amount Q1 enters the ignitable region Z ″). This ignition occurs when the air-fuel ratio is thin, and the ignition state is volatile and unstable. In this case, the microcomputer 61 executes the same ignition control as in the case of ignition at the intersection C1. That is,
At the time of detection of ignition of the gas burner 21, the process immediately shifts to the next stage and changes the gas amount from the first gas amount Q1 to the second gas amount Q2.
Up to. As a result, the state where the air-fuel ratio is thin (corresponding to the intersection C4) is immediately shifted to the state where the air-fuel ratio is appropriate (corresponding to the intersection C2), and the flame state becomes stable. After this shift, the gas supply state at the second gas amount Q2 is maintained for a predetermined time T0.

The microcomputer 61 executes normal control after a lapse of a predetermined time TO in the ignition control. In the normal control, opening operation of the electromagnetic opening / closing valve 32, control of the pressure proportional control valve 33, control of the fan 12, and control of the water amount control valve 27 are performed. The fan speed and the gas supply amount in the normal control are much larger than those in the ignition control.

Next, the routine including the gas amount control at the time of ignition executed by the microcomputer 61 will be described in detail with reference to the flowchart of FIG. Tap 24b
Is opened and the flow sensor 25 detects a water flow, the routine is started. Pre-purge is performed in step 100, and fan control during ignition is executed in step 101. As a result, the fan 12 is controlled to have a predetermined rotation speed. Next, at step 102, the pressure proportional control valve 3
The amount of gas is controlled so that the first gas amount Q1 is achieved by controlling the opening degree of No. 3, and the igniter 40 is turned on in step 103 to start the discharge. In the next step 104, it is judged whether or not the flame of the gas burner 21 is detected by the frame rod electrode 50. When a negative determination is made in step 104, it is determined in step 105 whether the elapsed time from the start of gas supply with the first gas amount Q1 is the predetermined time T1 or more. If a negative decision is made in step 105, step 1
Return to 01. In this way, the gas supply control state at the initial stage is continued.

When the predetermined time T1 has elapsed, an affirmative decision is made in step 105, and in step 106, fan control at the time of ignition, that is, fan control at the above-mentioned predetermined number of revolutions is executed as in step 101. In step 107, the pressure proportional control valve 33 is controlled to control the gas amount so as to become the second gas amount Q2, and in step 108, the igniter 40 is turned on and the discharge is continued. In this way, the affirmative judgment in step 105 shifts the gas supply control from the initial stage to the next stage. In step 109, it is determined whether the flame from the gas burner 21 is detected by the frame rod electrode 50. If an affirmative decision is made in step 109, step 11
At 0, the flag FLG is set. This flag FLG indicates the fact that flame was detected by the frame rod electrode 50. In step 111, it is determined whether or not the elapsed time after the flame is detected by the frame rod electrode 50 has exceeded a predetermined time T0. When a negative determination is made in step 111, the process returns to step 106.

If an affirmative judgment is made in step 111, that is, if it is confirmed that the ignition state after ignition is stable for the predetermined time T0, the flag FLG is cleared in step 117. In the next step 118, normal control is entered. In normal control, the opening of the pressure proportional control valve 33 is controlled to control the gas amount, the fan 12 is controlled to control the air amount, and the water amount control valve 27 is controlled so that the hot water temperature matches the set temperature. Control the amount of water.

When a negative determination is made in step 109, it is determined in step 112 whether the flag FLG is set. When a negative determination is made in step 112, it is determined in step 113 whether or not the elapsed time from the start of the gas amount control with the second gas amount Q2 (the control start in the next stage) has passed the predetermined time T2. When a negative determination is made in step 113, the process returns to step 106. Steps 109 and 11
Until the affirmative judgment is made in 2, 113, steps 106, 1
07 and 108 are repeatedly executed. As described above, in the next stage, the igniter 40 is turned on while the second gas amount Q2 is being supplied to continue the discharge, and the ignition is tried until the predetermined time T2.

When the affirmative judgment is made in step 112, that is, when the flame is extinguished after the ignition is once performed, or when the affirmative judgment is made in step 113, that is, the ignition is not performed even if the T2 ignition is executed for the predetermined time, step 114 The flag FLG is reset with. Next Step 1
The gas supply is stopped at 15, and the fan 12 is started at step 116.
After the unburned gas is discharged from the duct 13, the program ends.

Next, a routine which is a characteristic part of the present invention will be described. In the gas supply state with the first gas amount Q1 by the ignition control in the initial stage, the ignition is performed at a low air amount W1 due to the negative pressure in the room. Also, depending on the type of gas, the type of igniter 40, and the installation state of the duct 13, the air pressure in the room is atmospheric pressure W2.
It may ignite even at. In the latter case, the flame in the state where the air-fuel ratio is thin is jumpy and unstable. Therefore,
When the ignition is detected in the initial stage, the flame is stabilized by the routine described below in consideration of the possibility that the latter situation has occurred. Step 1 by ignition detection in the initial stage
An affirmative decision is made in 04, and the processing proceeds to Step 110, Step 1
After the negative judgment in step 11, steps 106, 107, and 10
Execute 8. In this way, the process immediately shifts to the next stage without waiting for the affirmative judgment in step 105. In the next step 107, the gas amount is increased to the second gas amount Q2.
This increase in the amount of gas increases the amount of gas with respect to the amount of air, so that the flame state that was unstable in the initial stage is immediately stabilized.

Another embodiment of the present invention will be described below. In these embodiments, the fan control and the igniter control are the same as those in the first embodiment, so the description thereof will be omitted and only the gas supply control will be described. The code Q
1 and Q2 represent the same gas amount as in the first embodiment. In this embodiment, the gas is supplied at the first gas amount Q1 in the initial stage, and the process shifts to the next stage at the time when ignition is detected. In this next stage, the gas amount is gradually and linearly increased to the gas amount Q2 over a predetermined time T0 seconds. As a result, it is possible to stabilize even a flame that tends to fly and is unstable. In addition, since the amount of gas gradually increases in the next stage, it is possible to suppress the generation of unburned gas or soot that accompanies a rapid increase in the amount of gas. When ignition cannot be detected for a predetermined time in the initial stage, the process shifts to the next stage in the same manner as in the first embodiment (see the imaginary line).

In the embodiment of FIG. 7, the gas amount is linearly and gradually increased to the second gas amount Q2 regardless of whether ignition is detected. In this embodiment, when ignition is detected in the process of increasing the gas amount, the state is before the ignition is detected, and the initial stage is obtained after the ignition is detected. As a result, the amount of gas increases in the initial stage and the next stage, so it is possible to suppress the generation of unburned gas or soot that accompanies a rapid increase in the amount of gas. In addition,
When ignition is not detected in the process of increasing the gas amount, the gas amount Q2 is maintained for a predetermined time as the next stage (see the imaginary line).

In the embodiment shown in FIG. 8, the gas amount is controlled to linearly and gradually increase so that the gas amount becomes the second gas amount in a predetermined time in the initial stage. After the gas burner 21 is ignited, the supply gas amount is immediately increased to the gas amount Q2 in the next stage, the ignition is continuously confirmed for a predetermined time T0, and then the normal control is executed. As a result, the amount of unburned gas released to the casing 11 in the initial stage can be reduced. When ignition is not detected in the process of increasing the gas amount, the gas amount Q2 is maintained for a predetermined time as the next stage (see the imaginary line).

[0025]

According to the first aspect of the present invention, even when ignition is performed in a state where the air-fuel ratio is thin, it is possible to shift to an appropriate air-fuel ratio, and it is possible to stabilize a flaky and unstable flame. According to the second aspect, since the gas supply control in the next stage is performed for a predetermined time, the flame can be stabilized. Also,
Since the transition from the initial stage to the next stage is performed at the time of ignition detection, the time required for ignition control can be shortened. According to the third aspect, the unstable flame can be immediately shifted to the stable flame. According to the fourth aspect, since the gas amount does not increase rapidly, it is possible to suppress the generation of unburned gas and soot. Claim 5
Then, the unburned gas supplied to the burner before ignition can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a configuration diagram showing an outline of an embodiment of the present invention.

FIG. 3 is a time chart of gas amount / air amount control when ignition is performed with a second gas amount in the embodiment.

FIG. 4 is a time chart of gas amount / air amount control when ignition is performed with the first gas amount in the embodiment.

FIG. 5 is a flowchart showing a routine including ignition control executed by a microcomputer.

FIG. 6 is a time chart showing gas amount and air amount control in another embodiment.

FIG. 7 is a time chart showing gas amount / air amount control in another embodiment.

FIG. 8 is a time chart showing gas amount / air amount control in another embodiment.

FIG. 9 is an explanatory diagram illustrating an installation situation of a gas combustion device.

FIG. 10 is a diagram showing an ignitable region.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 burner 2 gas supply means 3 fan 4 igniter 5 ignition control execution means 6 normal control execution means 7 fan control means 8 igniter control means 9 ignition detection means 10 gas supply control means 21 gas burner (burner) 30 gas supply means 33 pressure proportional control Valve 12 Fan 40 Igniter 50 Frame rod electrode (ignition detection means) 61 Microcomputer (ignition control execution means, normal control execution means)

Claims (5)

[Claims] 1. A burner, gas supply means for supplying gas to the burner, a fan for supplying room air to the burner, an igniter for igniting the burner, ignition control execution means, and air supply by a fan after ignition control and In the gas combustion apparatus provided with a normal control execution means for controlling gas supply by the gas supply means, the ignition control execution means includes: (a) fan control means for controlling the fan at a lower rotation speed than during normal control; (B) igniter control means for operating the igniter to ignite the burner, (c) ignition detection means for detecting ignition to the burner, and (d) ignition by controlling the gas supply means. Control the amount of gas to be supplied, and in the initial stage, the amount of gas should be lower than the amount of gas corresponding to the air volume expected by the fan speed. If the ignition gas is controlled by the ignition detection means at this initial stage and the supply gas amount is controlled, the process proceeds to the next stage with the passage of time, and even if the ignition is detected by the ignition detection means at this initial stage. , A gas combustion control means for increasing the supply gas amount from the initial stage in advance to the fan control and the gas supply control by the normal control executing means in the next stage. apparatus. 2. The gas supply control means according to claim 1, wherein the gas supply control in the next stage is performed for a predetermined time, and the transition from the initial stage to the next stage is performed at the ignition detection time. Gas combustion device. 3. The fan control means controls a fan at a predetermined rotation speed, and the gas supply control means has a predetermined lower gas quantity than a gas quantity corresponding to an air volume expected by the predetermined fan rotation speed in the initial stage. The first gas quantity is supplied and this first
When the ignition is not detected by the ignition detecting means for another predetermined time in the gas supply state with the gas amount, the process proceeds to the next stage at the time when the other predetermined time elapses and is expected by the predetermined fan rotation speed. Immediately increase the supply gas amount up to a predetermined second gas amount corresponding to the air flow rate, and when ignition is detected by the ignition detecting means in the gas supply state with the first gas amount, immediately shift to the next stage. The gas combustion apparatus according to claim 2, wherein the supply gas amount is increased to the second gas amount. 4. The gas combustion apparatus according to claim 1, wherein the gas supply control means gradually increases the supply gas amount to a predetermined gas amount with the passage of time in the next stage. 5. The gas combustion apparatus according to claim 1, wherein the gas supply control means gradually increases the supply gas amount in the initial stage.