KR19980087110A - Combustion device - Google Patents

Abstract

In order to provide a combustion device in which the combustion amount of the burner does not abruptly decrease even if the supply amount of combustion air supplied to the burner is drastically and drastically reduced.

Blowing control means 32 which adjusts the rotational speed of the blower 15 so that the flow volume of the combustion air detected by the air quantity detecting means 16 may match a predetermined reference flow rate, and it is supplied to a burner by the blower 15. The thermocouple 11 and the electromotive force of the thermocouple 11 to generate a thermoelectric power according to the air ratio, which is a ratio between the actual amount of air and the amount of air required for combustion of the burner, so that the electromotive force of the thermocouple 11 matches the reference voltage for a predetermined reference air ratio. The proportion which controls the opening degree of the proportional control valve 18 to the 2nd rate of change smaller than the 1st rate of change which is the rate of change of the rotational speed at the time of adjusting the rotational speed of the blower 15 by the blowing control means 32 The valve control means 30 is provided.

Description

Combustion device

The present invention relates to a combustion apparatus that performs stable combustion by keeping the air-fuel ratio and the air ratio constant.

In the related art, a gas water heater or a gas fan heater, which is a combustion device, is provided with a proportional control valve for adjusting the amount of fuel gas supplied to a burner and a blower for adjusting the amount of combustion air supplied to the burner. It is known to carry out the so-called air-fuel ratio control for burning the burner while keeping the ratio between the supply amount of the fuel gas and the supply amount of combustion air constant.

As the air-fuel ratio control as described above, for example, an air quantity detection means for detecting a supply flow rate of the combustion air supplied to the burner is provided, and the detection flow rate by the air quantity detection means is disturbed such as an intake pipe or an exhaust pipe. By changing the rotational speed of the blower, the flow rate of the combustion air of the burner is kept constant by adjusting the rotational speed of the blower so that the detection flow rate by the air quantity detecting means is maintained at a predetermined reference flow rate.

In general, since the supply amount of fuel gas does not change due to disturbance, the supply amount of combustion air is kept constant even if disturbance occurs. Thus, the ratio between the supply amount of fuel gas and the supply amount of combustion air is constant. It can hold | maintain and can perform stable combustion.

Further, an air ratio detecting means for detecting an air ratio (λ: actual supply air amount / required air amount), which is a ratio between the air amount actually supplied to the burner by the blower and the air amount required for combustion determined according to the supply amount of fuel gas supplied to the burner. And carbon monoxide generated during combustion of the burner by performing an air ratio control to adjust the opening degree of the proportional control valve so that the air ratio λ detected by the air ratio detection means is maintained at a predetermined reference air ratio λB. It is known to control the amount of (CO) and nitrogen oxides (NO _X ).

As an air ratio detecting means, a thermocouple is provided in the vicinity of the burner and the air ratio λ is detected from the correlation between the electromotive force of the thermocouple and the air ratio λ. The correlation between the electromotive force of the thermocouple and the air ratio [lambda] becomes a quadratic upward convex curve in which the electromotive force of the thermocouple becomes the maximum at [lambda] = 1 as shown in FIG.

Therefore, when the reference air ratio λB is set to a value of 1 or more, when the electromotive force V of the thermocouple exceeds the reference power VB corresponding to the reference air ratio λB, it is supplied to the burner by the proportional control valve. The air ratio λ is increased by reducing the supply amount of fuel gas to be increased, and increasing the air ratio λ when the fuel gas is lower than the reference power VB by increasing the supply amount of fuel gas supplied to the burner by the proportional control valve. Can be maintained as λ = λB.

By performing the air-fuel ratio control and the air ratio control in parallel, a stable burner can be burned while controlling generation of carbon monoxide (CO) and nitrogen oxides (NO _X ).

However, when the air / fuel ratio control and the air ratio control are performed in parallel, when a disturbance such as an intake pipe blockage occurs and the supply amount of the combustion air supplied to the burner is drastically and greatly reduced, the blower according to the air / fuel ratio control The process of raising the rotational speed of the air and the process of increasing the air ratio by reducing the opening degree of the proportional control valve according to the air ratio control are simultaneously performed.

In general, the rate of change of the rotational speed according to the amount of energization of the fan motor provided in the blower is smaller than the rate of change of the opening degree according to the amount of energization of the proportional control valve. Therefore, in this case, the reduction of the proportional control valve opening degree is performed earlier than the increase of the blower rotational speed, and the supply amount of the fuel gas supplied to the burner is greatly reduced.

As a result, the combustion amount (heating amount) of the burner is greatly reduced, and, for example, in a hot water heater, the tapping temperature drops abruptly, causing a problem for the user.

SUMMARY OF THE INVENTION An object of the present invention is to provide a combustion apparatus in which the combustion amount of a burner does not abruptly decrease even if the supply amount of combustion air supplied to the burner is drastically and drastically reduced.

1 is a graph of the correlation between the air ratio and the thermoelectric power of the thermocouple.

2 is a configuration diagram of a hot water heater which is the combustion device of the first embodiment of the present invention.

3 is a control block diagram of a controller provided in the hot water heater of FIG.

4 is an operational flowchart of the controller of FIG.

5 is an operation flowchart of the controller of FIG. 3.

6 is a configuration diagram of a hot water heater which is a combustion device according to a second embodiment of the present invention.

7 is a control block diagram of a controller provided in the hot water heater of FIG. 6.

Explanation of symbols for main parts of the drawings

1.Hot water main body 2.Burner

3.combustion chamber 4.heat exchanger

5. Gas Supply Pipe 6. Hot Water Pipe

7. Blower 8. Controller

9.Operator 10.Ignition electrode

11.Thermocouple 12.Introduction

13.Intake vent 14.Fan

15.fan motor 16.air flow sensor

17. Kettle valve 18. Proportional control valve

19.Flow sensor 20.Intake temperature sensor

21.Timmer temperature sensor 22.Temperature setting switch

23.Display 24.Rotation speed sensor

25. Current detecting means 30. Proportional valve control means

31. Target combustion amount calculation unit 32. Blowing control means

33. Change rate setting means 34. Control stop means

35. Target air flow rate calculation unit 36. Current flow rate calculation unit

37. Reference voltage calculation means 38. Comparison

39. Compensation value calculation part 40. Basic energization amount calculation part

41. Determination of power supply 70. Air detection means

71. Target rotation speed calculation unit

A first embodiment of the present invention provides a burner, a proportional control valve for adjusting a supply amount of fuel gas supplied to the burner, a blower for adjusting a supply amount of combustion air supplied to the burner, and the like. And an air volume detecting means for detecting a flow rate of the combustion air supplied to the burner, and a blowing control for adjusting the rotational speed of the blower so that the flow rate of the combustion air detected by the air amount detecting means is equal to a predetermined reference flow rate. Means, a thermocouple installed toward the burner and generating a thermoelectric power according to an air ratio that is a ratio between the actual air amount supplied to the burner by the blower and the air amount required for combustion of the burner, and the thermoelectric power of the thermocouple. The opening degree of the proportional control valve is controlled by the blowing control means to match the reference voltage corresponding to the reference air ratio. In that it includes a proportional valve control means for adjusting a second change rate smaller than a rate of change the first rate of change of the rotational speed of the entire time to adjust the speed is characterized.

According to the present invention, the second rate of change when adjusting the opening degree of the proportional control valve by the proportional valve control means is set smaller than the first rate of change when adjusting the rotational speed of the blower by the blowing control means. do. Therefore, when the flow rate of the combustion air supplied to the burner by the disturbance is drastically reduced and thus the air ratio is also drastically reduced, the blow control means increases the rotational speed of the blower to maintain the air-fuel ratio constant. Is performed while the proportional valve control means reduces the opening degree of the proportional control valve and precedes the process of keeping the air ratio constant.

Therefore, the opening degree of the proportional control valve is not directly reduced by the proportional valve control means in a state where the supply amount of combustion air supplied to the burner is drastically reduced, and the rotational speed of the blower is controlled by the blowing control means. The recovery (rising) process is started and the opening amount of the proportional control valve is reduced as the supply ratio of combustion air supplied to the burner increases and the air ratio increases.

Therefore, the amount of reduction in the amount of fuel gas supplied to the burner required to match the air ratio detected by the thermocouple to the reference air ratio can be reduced, thereby preventing the combustion amount of the burner from decreasing drastically.

In addition, the change rate setting means for setting the second rate of change smaller is provided as the amount of adjustment of the blower rotational speed by the blower control means required to match the blow rate of the blower to the reference flow rate.

If the supply amount of combustion air supplied to the burner is greatly reduced, the amount of adjustment of the blower rotational speed by the blower control means is increased, and the time required for matching the blower amount of the blower to the reference flow rate becomes long. At this time, according to the present invention, the second change rate is set smaller as the adjustment amount of the blower rotational speed is larger. Therefore, the speed of reducing the opening degree of the proportional valve by the proportional valve control means becomes slow, and the adjustment of the blower rotational speed by the blow control means is performed in advance. Therefore, the reduction amount of the fuel gas supply amount supplied to the burner by the proportional valve control means can be reduced, and the burn amount of the burner can be prevented from decreasing.

The adjustment of the proportional control valve opening degree by the proportional valve control means is stopped by the proportional valve control means when the amount of adjustment of the blower rotational speed by the blowing control means necessary for matching the blowing amount of the blower to the reference flow rate is equal to or greater than a predetermined upper limit value. Characterized in that the adjustment stop means for installing.

When the adjustment amount of the blower rotational speed by the blower control means exceeds a predetermined upper limit, the amount of combustion supplied to the burner is greatly reduced, resulting in an extremely low air ratio. At this time, when the proportional valve control means reduces the opening degree of the proportional control valve to match the air ratio with the reference air ratio, the supply amount of fuel gas supplied to the burner is drastically reduced and the combustion amount of the burner is greatly reduced. Decreases.

In such a case, according to the present invention, the adjustment stop means stops the adjustment of the proportional control valve by the proportional valve control means. Therefore, it is possible to prevent the combustion amount of the burner from being drastically reduced by reducing the fuel gas supply amount supplied to the burner.

In addition, the air amount detecting means is characterized in that the air flow sensor.

As described above, according to the present invention, it is possible to easily detect the supply amount of combustion air supplied to the burner by using an air flow sensor.

The air amount detecting means includes a rotation speed detecting means for detecting a rotational speed of the blower and a current detecting means for detecting an amount of energization to the blower, and the rotational speed of the blower and the amount of energization to the blower. It is characterized by detecting the flow rate of the combustion air supplied to the burner from the relationship.

When the supply amount of combustion air supplied to the burner decreases due to the blockage of the intake port, the amount of energization to the blower required to rotate the blower at a predetermined rotation speed decreases. That is, since the energization amount to the blower with respect to the rotational speed of the blower increases or decreases with the increase or decrease of the supply amount of the combustion air supplied to the burner, the supply amount of the combustion air supplied to the burner can be detected using this. .

Therefore, in particular, the rotational speed of the blower is feedback controlled so that the rotational speed of the blower is a predetermined target rotational speed. With respect to the combustion provided with the rotational speed control means, it is possible to configure the air quantity detecting means by adding a current detecting means for detecting the amount of energization to the blower, and the installation cost of the air quantity detecting means can be lowered. .

1st Embodiment of this invention is described with reference to FIGS. 1 is a correlation graph of the thermoelectric power of the thermocouple provided in the combustion apparatus of the first embodiment and the air ratio, FIG. 2 is a configuration diagram of a hot water heater which is the combustion apparatus of the first embodiment, and FIG. 3 is shown in FIG. 4 is a flowchart showing the air-fuel ratio control operation of the hot water heater shown in FIG. 2, and FIG. 5 is a flowchart showing the control operation of the air ratio of the hot water heater shown in FIG.

With reference to FIG. 2, the hot water heater of this 1st embodiment taps hot water of the target temperature set by the user, (1) a hot water heater main body, (2) the combustion chamber formed in the hot water heater main body 1 ( The burner accommodated in 3), 4 is a heat exchanger installed into the water heater body 1 above the combustion chamber 3, 5 is a gas supply pipe for supplying fuel gas to the burner 2, 6 is a heat exchanger. Hot water supply pipe piped through (4), (7) is a blower for supplying combustion air to the burner (2) in the combustion chamber (3), (8) a controller for controlling the operation of the hot water heater, (9) tapping temperature This is an operating device for performing setting operation and the like. In the combustion chamber 3, an ignition electrode 10 for generating a spark discharge for igniting the burner 2 and a thermocouple 11 for detecting the combustion state of the burner 2 (with or without fire and ignition) are disposed. .

The blower 7 is located toward the inlet 13 of the introduction passage 12 of the combustion air, and a fan motor 15 for rotating the fan 14 and the fan 14 installed in the introduction passage 12. The combustion air necessary for the combustion of the burner 2 is sucked by the rotation of the fan 14 from the intake port 13 of the introduction passage 12, and the combustion air is introduced into the combustion chamber through the introduction passage 12. Supply to (3).

The introduction passage 12 is provided with an air flow sensor 16 which is an air quantity detecting means for detecting the flow rate of the combustion air supplied to the burner 2.

The gas supply pipe 5 includes a kettle valve 17 for opening and closing the gas supply pipe 5 sequentially from an upstream side thereof, and a proportional control valve for adjusting the supply amount of the fuel gas supplied from the gas supply pipe 5 to the burner 2 ( 18) is installed.

The hot water supply pipe 6 has a flow rate sensor 19 for detecting the amount of water supplied to the hot water supply pipe 6 on the upstream side of the heat exchanger 4 and an inlet temperature sensor 20 for detecting the temperature of the water supplied to the heat exchanger 4. ), And a tapping temperature sensor 21 for detecting the temperature of the water heated by the heat exchanger 4 is provided on the downstream side of the heat exchanger 4. In this case, the water intake temperature sensor 20 and the tapping temperature sensor 21 are constituted by a thermistor which is a thermosensitive resistor, for example.

The downstream end of the hot water supply pipe 6 is connected to a hot water supply (not shown), for example, in a kitchen.

The manipulator 9 is provided with a temperature setting switch 22 for setting the tapping target temperature, and an indicator 23 for notifying tapping target temperature, water heater abnormality, and the like.

The controller 8 is constituted by an electronic circuit such as a microcomputer, a memory, an I / O unit, and a burner detected through each of the sensors 16, 19, 20, 21 and the thermocouple 11, respectively. The ignition electrode 10 and the fan motor 15 based on the supply amount of combustion air supplied to (2), the water supply amount of the hot water supply pipe 6, the intake temperature and the tapping temperature, and the combustion state detection data of the burner 2, etc. The operation of the kettle valve 17, the proportional control valve 18, and the indicator 23 is controlled.

Here, with reference to FIGS. 2-5, the control operation of the hot water heater by the controller 8 is demonstrated.

When the user operates a hot water supply field (not shown) mounted on the downstream end of the hot water supply pipe 6 shown in FIG. 2 and the water flow to the hot water supply pipe is detected by the flow sensor 19, the controller 8 The fan motor 15 is driven to start the supply of combustion air to the burner 2. In addition, the controller 8 opens the kettle valve 17 to start supplying fuel gas to the burner. In the above state, the controller 8 generates a spark discharge through a sparker (high voltage generating circuit) not shown in the ignition electrode 10 to ignite the burner 2 and to burn the burner 2. It starts.

As shown in FIG. 3, the controller 8 includes a proportional valve control means 30, a target combustion amount calculation unit 31, a blowing control means 32, a change rate setting means 33, and an adjustment stop means 34. do. When combustion of the burner 2 is started, the target combustion amount calculation unit 31 passes through the hot water supply pipe 6 detected by the flow sensor 19, the intake temperature sensor 20 and the tapping temperature sensor 21, respectively. The target combustion amount of the burner 2 for matching the tapping temperature with the target temperature is determined at every moment based on the detection data of the intake temperature and the tapping temperature and the tapping temperature set by the tapping temperature setting switch 22.

Then, the target air amount calculating unit 35 provided in the blowing control means 32 calculates the supply amount of combustion air according to the target combustion amount, and instructs the energization amount calculating unit 36 as the supply amount as the target air amount. . The energization amount calculating unit 36 supplies the fan motor so that the target air amount indicated from the target air amount calculating unit 35 matches the flow rate of the combustion air actually supplied to the burner 2 detected by the air flow sensor 16. 15) Adjust the amount of electricity to the furnace.

4 is a flowchart showing the operation of controlling the supply amount of combustion air supplied to the burner 2 by the blowing control means 32. As shown in FIG. Referring to FIG. 4, the blowing control means 32 substitutes (resets) 0 into F1 and F2 in steps STEP1 and STEP2, respectively. The flags F1 and F2 are for prohibiting restart of the timers T1 and T2 described later, respectively.

The blowing control means 32 substitutes 1 for the correction value β in step STEP3. The value of the correction value β is then supplied to the actual burner 2 detected by the target air amount and air flow sensor 16 instructed by the energization amount calculation unit 36 in accordance with the target air amount calculation unit 35. It varies with the difference with the flow volume of the combustion air which becomes, and the electricity supply amount to the fan motor 15 is determined by the following formula.

Power Supply = Reference Power Supply × Correction Value (β)

Then, the reference energization amount is determined by the energization amount calculation unit 36 in accordance with the target air amount calculated by the target air amount calculation unit 35.

When the actual amount of air detected by the airflow sensor 16 in step STEP4 is equal to or larger than the target air amount x 95%, the flow advances to step STEP20. In step STEP20, when the actual amount of air is less than or equal to the target amount of air x 105%, the flow advances to step STEP4. That is, when the actual air amount detection value by the air flow sensor 16 is within the target air amount ± 5% range, steps ST4 and ST20 are repeatedly executed so that the correction value β is not changed.

In contrast, when the detected value of the actual combustion air supply amount by the airflow sensor 16 in step STEP4 is less than the target air amount x 95%, the flow advances to step STEP5 (at this time, the flag F1). = 0), and the energization amount correcting operation to the fan motor 15 by the energization amount calculation unit 36 is started. The energization amount calculating unit 36 substitutes (sets) 1 into F1 in step STEP6, inserts (resets) 0 into F2 in step STEP7, and starts the fixed timer T1 in step STEP8. do.

When the fixed timer T1 time's up in step STEP9, the flow advances to step STEP10, where 0 is substituted (reset) in the flag F1, and in step STEP11, the energization calculation unit 36 Is added to the correction value β by. As a result, the amount of current supplied to the fan motor 15 determined by the amount of electricity calculation unit 36 increases, and the rotational speed of the fan motor 15 increases.

When the fixed timer T1 has not timed up in step STEP9, the process proceeds to step STEP4. At this time, since the flag F1 is 1 (set state), the process goes from step STEP5 to step STEP9, and the restart of the fixed timer T1 in step STEP8 is stopped.

By the processing of steps STEP4-STEP11, in step STEP9, the detected value of the actual combustion air supply amount by the air flow sensor 16 in step STEP4 becomes the target air amount x 95%. Each time the fixed timer T1 times up, the energization amount to the fan motor 15 is increased to increase the rotational speed of the fan motor 15.

If the detected value of the actual amount of combustion air supply by the airflow sensor 16 exceeds the target air amount x 105% in step STEP20, the process proceeds to step STEP21 (at this time, the flag F2). = 0), the energization amount calculating unit 36 substitutes (sets) 1 into the flag F2 in step STEP22 and assigns (resets) 0 to the flag F1 in step STEP23 to step STEP24. Starts the fixed timer T2 with the setting time of 1 second.

When the fixed timer T2 times up in step STEP25, the flow advances to step STEP26, where 0 is substituted (reset) in the flag F2, and in step STEP27, it is corrected by the energization calculation unit 36. 0.1 is subtracted from the value β. As a result, the amount of current supplied to the fan motor 15 calculated by the amount of electricity calculation unit 36 decreases, and the rotational speed of the fan motor 15 decreases.

When the fixed timer T2 does not time up in step STEP25, the process proceeds to step STEP4. At this time, since the flag F2 is 1 (set state), the process goes from step STEP21 to step STEP25, and the restart of the fixed timer T2 in step STEP24 is stopped.

By the processing of steps STEP4 and STEP20 to STEP27, it is fixed in step STEP25 until the detected value of the actual air amount by the airflow sensor 16 becomes less than the target air amount x 105% in step STEP20. Each time the timer T2 times up, the energization amount to the fan motor 15 is reduced, so that the rotation speed of the fan motor 15 is reduced.

By the operation of the energization amount calculating section 36, even when disturbances such as foreign matters are attached to the intake port 13, the supply amount of combustion air supplied to the burner 2 is maintained at the target air amount. And since the supply amount of the fuel gas supplied to the burner 2 does not change with a disturbance, the ratio (fuel ratio) of the supply amount of combustion air and the supply amount of fuel gas can be kept constant.

In addition, the proportional valve control means 30 provided in the controller 8 includes the reference voltage calculating means 37, the comparing unit 38, the correction value calculating unit 39, and the basic conduction amount calculation as shown in FIG. It has a part 40 and an electricity supply quantity determining part 41. The basic conduction amount calculating unit 40 determines the supply amount of fuel gas necessary to obtain the target combustion amount calculated by the target combustion amount calculating unit 31, and opens the opening degree according to the supply amount of the fuel gas to the proportional control valve 18. Calculate the basic energization amount.

The reference voltage calculating means 37, the comparator 38, the correction value calculating means 39, and the energization amount determining unit 41 are actually supplied with the amount of combustion air supplied to the burner 2 and combustion at the target combustion amount. This is for burning the burner 2 by maintaining an air ratio (λ: actual supply air amount / required air amount), which is a ratio with the supply amount of combustion air, required at a predetermined reference air ratio λB.

As shown in the graph of FIG. 1, the relationship between the thermoelectric power V and the air ratio λ of the thermocouple 11 when burning the burner 2 is λ = 1 and the thermoelectric power of the thermocouple 11 is It becomes the upwardly convex quadratic curve which is the maximum. Therefore, when the reference air ratio λB is set to a value of 1 or more, the opening degree of the proportional control valve 18 when the thermoelectric power V of the thermocouple 11 is less than the reference voltage VB corresponding to the reference air ratio λB. To increase the supply amount of fuel gas supplied to the burner 2, and when the thermoelectric power V of the thermocouple 11 exceeds the reference voltage VB, the opening degree of the proportional control valve 18 is decreased to reduce the burner. By reducing the supply amount of the fuel gas supplied to (2), the burner 2 can be combusted by maintaining the air ratio λ at the reference air ratio λB.

Since the larger the air ratio, the amount of carbon monoxide (CO) and nitrogen oxides (NO _X ) generated during combustion of the burner 2 decreases. Therefore, in the first embodiment, the reference air ratio λB is set to 1.3, which is larger than one. Doing.

Hereinafter, with reference to the flowchart shown in FIG. 5, operation | movement of air ratio control by the proportional valve control means 30 is demonstrated.

The proportional valve control means 30 substitutes (resets) 0 into the flags F3 and F4 in steps STEP50 and STEP51, and substitutes 1 in the correction value? In step STEP52. The flags F3 and F4 are for prohibiting restart of the variable timers T3 and T4 described later, respectively. The value of the correction value α is then determined by the correction value calculation unit 39 by the reference voltage calculating means 37 according to the target combustion amount and the electromotive force V of the thermocouple 11. The amount of energization from the energization amount determining unit 41 to the proportional control valve 18 is determined by the following equation.

Power Supply = Basic Power Supply × Correction Value (α)

As described above, the basic energization amount is calculated according to the target combustion amount determined by the target combustion amount calculation unit 31 in the basic electricity amount calculation unit 40.

In step STEP53, the comparison unit 38 compares the reference voltage VB with the thermoelectric power V of the thermocouple 11 and the thermoelectric power V of the thermocouple 11 is its reference voltage VB − If it is 0.2 mV or more, the process proceeds to step STEP70, and in step STEP70, if the thermocouple's thermoelectric power V is less than the reference voltage VB + 1.2 mV, the process proceeds to step STEP53. That is, when the thermoelectric power V of the thermocouple 11 is in the range of the reference voltage VB ± 0.2 mV, steps STEP53 and STEP70 are repeatedly executed and the correction value α is not changed.

In contrast, in step STEP53, when the thermoelectric power V of the thermocouple 11 is less than the reference voltage VB-0.2 mV, the process proceeds to step STEP54. The step STEP54 is a process by the adjustment stop means 34, and the correction value (β: adjustment amount of rotation speed of the fan motor 15) to the fan motor 25 calculated by the energization amount calculation unit 36. ) Exceeds a predetermined upper limit value, i.e., when the flow rate of the combustion air actually supplied to the burner 2 detected by the airflow sensor 16 is greatly reduced, the proportional valve control after step (STEP55) The process of changing the correction value α by the means 30 is prohibited.

When the supply amount of combustion air supplied to the burner 2 is greatly reduced by the processing of the adjustment stop means 32, and the air ratio λ is also significantly reduced by the proportional control means 30, Since the thermoelectric power V of the thermocouple 11 corresponding to the air ratio λ coincides with the reference voltage VB corresponding to the reference air ratio λB, the supply amount of the fuel gas supplied to the burner 2 is reduced. This can prevent the situation in which the burn amount of the burner 2 is drastically reduced. Therefore, it is possible to prevent the temperature of the hot water taken out from the hot water supply pipe 6 rapidly dropping and causing discomfort to the user.

The step ST55 is a process by the change rate setting means 33, and the correction value (β: adjustment amount of the rotation speed of the fan motor 15) to the fan motor 15 calculated by the energization amount calculation unit 36. The set value of the variable timer T3 is longer than 1 second, which is the set value of the fixed timer T1 shown in the flowchart of FIG. 4, and the longer the value of the correction value β is, Is determined.

At this time, since the flag F3 is 0, the process proceeds from step STEP56 to step STEP57, assigns 1 to the flag F3 in step STEP57, and sets the flag (stepEP58) in step STEP58. 0 is substituted (reset) in F4) to start the variable tire T3 in step STEP59.

When the variable timer T3 times up in step STEP60, the flow advances to step STEP61, where 0 is substituted into the flag F3, and in step STEP62, the correction value calculating section 39 causes the correction value? ) Is added. As a result, the amount of energization to the proportional control valve 18 determined by the energization amount determining unit 41 increases, and the opening degree of the proportional control valve 18 is increased.

When the variable timer T3 does not time up in step STEP60, the flow advances to step STEP53. At this time, since the flag F3 is 1 (set state), the process goes from step STEP56 to step STEP60, and restarting the timer T3 in step STEP59 is prohibited.

By the processing of the steps STEP53-STEP62, the timer T3 in the step ST60 until the thermoelectric power V of the thermocouple 11 becomes the reference voltage VB-0.2 mV or more in step STEP53. Each time) increases, the energization amount to the proportional control valve 18 is increased, which increases the opening degree of the proportional control valve 18.

In addition, when the thermoelectric power V of the thermocouple 11 exceeds the reference constant voltage VB + 0.2 mV in step STEP70, the process proceeds to step STEP71. The step STEP71 is a process by the adjustment stop means 34, and the correction value (β: adjustment amount of the rotation speed of the fan motor 15) to the fan motor 15 calculated by the energization amount calculation unit 36. When the supply amount of the combustion air supplied to the burner 2 actually detected by the airflow sensor 16 is greatly increased when the value exceeds the predetermined upper limit value (in this case, the + side). The process of changing the correction value? By the proportional valve control means after STEP72) is prohibited.

When the amount of combustion air supplied to the burner 2 is increased by the processing of the stop means 34 and the air ratio λ is also greatly increased with this, the air ratio λ by the proportional control means 30. Since the coincidence with the reference air ratio λB is increased, the supply amount of the fuel gas supplied to the burner 2 can be increased to prevent a sudden increase in the combustion amount of the burner 2. Therefore, it is possible to prevent the temperature of the hot water taken out from the hot water supply pipe 6 to rise sharply to cause discomfort to the user.

Step STEP77 is a process by the change rate setting means 33, and the correction value (β: adjustment amount of rotation speed of the fan motor 15) to the fan motor 15 calculated by the energization amount calculating unit 36. ), The setting value of the variable timer T4 is longer than 1 second, which is the setting value of the fixed timer T2 shown in the flowchart of FIG. 4, and the value (absolute value) of the correction value β is increased. The longer it is determined.

At this time, since the flag F4 is 0, the process proceeds from step STEP73 to step STEP74, assigns 1 to the flag F4 in step STEP74, and sets the flag (stepEP75) in step STEP75. 0 is substituted (reset) in F3) to start the variable timer T4 in step STEP76.

When the variable timer T4 times up in step STEP77, the routine advances to step STEP78, where 0 is substituted into the flag F4, and in step STEP79, the correction value? 0.1 is subtracted from As a result, the energization amount to the proportional control valve 18 determined by the energization amount determining unit 41 is reduced, and the opening degree of the proportional control valve 18 is reduced.

When the variable timer T4 does not time up in step STEP77, the process proceeds to step STEP53. At this time, since the flag F4 is 1 (set state), the process goes from step STEP73 to step STEP77, and in step STEP76, restart of the variable timer T4 is prohibited.

By the processing of the steps STEP53 and STEP70 to STEP79, in step STEP70, the thermoelectric power V of the thermocouple 11 becomes less than or equal to the reference voltage VB + 0.2 mV, and varies in step STEP77. Each time the timer T4 times up, the energization amount to the proportional control valve 18 is reduced.

By operating the proportional valve control means 30 described above, the burner 2 can be burned by maintaining the thermoelectric power V of the thermocouple 11 at the reference voltage VB with respect to the reference air ratio λB. have.

Here, since the set values of the fixed timers T1 and T2 shown in the flow chart of FIG. 4 are fixed at 1 second, when the correction value β of the amount of energization to the fan motor 15 is increased or decreased, The rate of change (first rate of change) of the amount of energization (corresponding to the rotational speed of the fan motor 15) becomes constant.

Therefore, in step STEP55, the change rate setting means 33 sets the set value of the variable timer T3 to a time longer than the set value (1 second) of the fixed timer T1, and the proportional control means 30 Change rate (second rate of change) of the amount of current supplied when the correction value (alpha) of the amount of current supplied to the proportional control valve 18 (corresponding to the opening degree of the proportional control valve 18) is increased from the first rate of change. It can be made small.

That is, the control operation of the fan motor 15 rotational speed by the blowing control means 32 can be preceded by the control operation of the proportional control valve 18 opening degree by the proportional valve control means 30.

Further, in step STEP55, the set value of the variable timer T3 is set to a longer time as the correction value β of the amount of current supplied to the fan motor 15 calculated by the amount of current calculation unit 36 is larger. As the amount of current supplied to the fan motor 15 is increased and the amount of combustion air supplied to the burner 2 is restored, the opening degree of the proportional control valve 18 can be adjusted. Therefore, the correction amount of the opening degree of the proportional control valve 18 can be reduced, and the combustion amount of the burner 2 can be prevented from decreasing drastically.

Also in step STEP72, as in step STEP55, the set value of the variable timer T4 is set to a time longer than the set value (1 second) of the fixed timer T2, and the blow control means 32 The control operation of the rotational speed of the fan motor 15 can be preceded by the control operation of the opening of the proportional control valve 18 by the proportional valve control means 30.

Further, in step STEP72, the set value of the variable timer T4 is set to a longer time as the correction value β of the amount of current supplied to the fan motor 15 calculated by the amount of current calculation unit 36 is larger. As the amount of current supplied to the fan motor 15 decreases so that the amount of combustion air supplied to the burner 2 decreases, the opening degree of the proportional control valve 18 can be adjusted. Therefore, the correction amount of the opening degree of the proportional control valve 18 can be reduced, and the combustion amount of the burner 2 can be prevented from increasing significantly.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. 6 is a control block diagram of the controller 8 provided in the hot water heater, which is the combustion device of the second embodiment, and FIG. 7.

The hot water heater of the second embodiment shown in FIG. 6 is a method of detecting the supply amount of combustion air supplied to the hot water heater and burner 2 of the first embodiment shown in FIG. 2 and the rotation speed of the fan motor 15. The control method is different.

6, the hot water heater of this second embodiment does not have an air flow sensor 16 provided in the introduction path 12 of the hot water heater of the first embodiment, and detects the rotational speed of the fan motor 15. And a current detecting means 25 for detecting an amount of energization to the rotating speed detecting means 24 and the fan motor 15.

When the supply amount of the combustion air supplied to the burner 2 decreases due to the blockage of the air inlet 13 or the like, the amount of energization to the fan motor 15 required to rotate the fan 14 at a predetermined rotation speed decreases. . That is, the amount of energization of the fan 14 to the fan motor 15 relative to the rotational speed of the fan 14 (= rotational speed of the fan motor 15) is increased or decreased in accordance with the increase or decrease of the combustion air supplied to the burner 2.

As shown in Fig. 7, the air amount detecting means 70 provided in the controller 8 of the second embodiment is a burner based on the relationship between the rotational speed of the fan 4 and the amount of energization to the fan motor 15. The amount of combustion air actually supplied to (2) is detected.

With reference to FIG. 7, the controller 8 of this 2nd Embodiment differs only in the structure of the said 1st Embodiment from the ventilation control means 32. As shown in FIG. The blowing control means 32 of the second embodiment includes the target air amount calculating portion 35, the target rotational number calculating portion 71, the energization amount calculating portion 36, the current detecting means 25, and the air amount detecting means 70. It is composed of

The target air amount calculating unit 35 calculates a target air amount which is a target value of the combustion air supplied to the burner 2 according to the target combustion amount calculated by the target combustion amount calculating unit 31 as in the first embodiment. do. The target rotational speed calculating unit 71 compares the target air quantity with the amount of combustion air actually supplied to the burner 2 calculated by the air quantity calculating means 70, and the target of the fan motor 15 necessary to match them. Calculate the rotation speed.

The energization amount calculating unit 36 adjusts the energization amount to the fan motor 15 so that the target rotational speed and the rotational speed of the actual fan motor 15 detected by the rotational speed detection means 24 coincide. As a result, the amount of energization to the fan motor 15 is adjusted so that the target air amount calculated by the target air amount calculating unit 35 is supplied to the burner 2 as in the first embodiment.

The configuration and operation of the proportional valve control means 30 are the same as those of the first embodiment.

In addition, in this 1st Embodiment and 2nd Embodiment, although the water heater was demonstrated as an example of a combustion apparatus, it is applicable also to another combustion apparatus, for example, a gas fan heater.

As described above, according to the present invention, even if the supply amount of combustion air supplied to the burner is drastically and drastically reduced, it is possible to provide a combustion device in which the combustion amount of the burner does not decrease drastically. The user can be convenient to use.

Claims (7)

A proportional control valve for controlling the burner, the fuel gas supply amount to the burner, a blower for adjusting the supply amount of combustion air to the burner, air amount detecting means for detecting a flow rate of the combustion air supplied to the burner, and A blowing control means for adjusting the rotational speed of the blower so that the flow rate of the combustion air detected by the air amount detecting means coincides with a predetermined reference amount, and an actual amount of air installed toward the burner and supplied to the burner by the blower; The opening of the proportional control valve so that the thermocouple generates a thermoelectric power corresponding to the air ratio which is the ratio of the amount of air required for combustion of the burner and the thermoelectric power of the thermocouple matches the reference voltage corresponding to a predetermined reference air ratio. ) Is greater than the first rate of change which is the rate of change of the rotational speed when the blower control means controls the rotational speed of the blower. A combustion device, characterized in that it includes a proportional valve control means for adjusting a second change rate. The change rate setting means for setting the second rate of change smaller as the adjustment amount of the rotational speed of the blower by the blow control means necessary for matching the blow rate of the blower to the reference flow rate. Combustor characterized in that. 3. The proportional valve control means according to claim 1 or 2, wherein when the amount of adjustment of the rotational speed of the blower by the blow control means necessary for matching the blow amount of the blower to the reference flow rate is equal to or greater than a predetermined upper limit value, Combustion apparatus characterized by providing the adjustment stop means for stopping the adjustment of the opening degree of the proportional control valve. 3. Combustion apparatus according to claim 1 or 2, wherein the air quantity detecting means is an air flow sensor. 4. The combustion apparatus according to claim 3, wherein said air quantity detecting means is an air flow sensor. The air flow rate detecting means according to claim 1 or 2, wherein the air quantity detecting means comprises a rotational speed detecting means for detecting a rotational speed of the blower and a current detecting means for detecting an amount of electricity supplied to the blower. And a flow rate of the combustion air supplied to the burner from the relationship between the amount of electricity supplied to the blower. 4. The air flow rate detecting means according to claim 3, wherein the air quantity detecting means comprises a rotational speed detecting means for detecting a rotational speed of the blower and a current detecting means for detecting an amount of energization to the blower. And a flow rate of the combustion air supplied to the burner from the relationship with the amount of energization of the burner.