JPH08152131A - Combistion device - Google Patents

Abstract

PURPOSE: To prevent the combustion conditions from deteriorating by a method wherein the rotative speed of a fan is detected, compared with a reference rotative speed at the time the fan is operated at a specified electric current in the beginning of operation to judge the clogging degree of air supply and exhaust lines. CONSTITUTION: In a gas supply device, fuel gas supplied from a gas supply pipe 12 is burned by a gas burner 1 in a combustion chamber 11 to heat water passing through a heat exchanger 10. All air fan 2 is provided on the combustion chamber 11 to supply combustion air and a proportioning valve 13 is mounted on the gas supply pipe 12 to control the feed rate of the fuel gas. In addition, values detected by a rotative speed detector 3 and a temperature sensor 4 are input to a controller 6. On the other hand, driving signals are output to a fan driving unit 5 and the proportioning value 13. The fan rotative speed detected is compared with a reference rotative speed at the time the air fan 2 is operated at a specified electric current in the beginning of operation to judge the clogging degree of air supply and exhaust lines. When the comparison result shows that the clogging degree of air supply and exhaust lines exceeds the reference value, the combustion by the burner 1 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device in a combustion equipment such as a gas water heater that burns fuel to heat water, and more specifically, detects fluctuations in the load of a blower fan due to clogging of a supply / exhaust system. However, the present invention relates to a combustion device in which the degree of clogging in the air supply / exhaust system is determined and appropriate combustion control is performed.

[0002]

2. Description of the Related Art In a gas combustion device equipped with a gas supply amount adjusting means such as a gas proportional valve for output control, a blower fan is also controlled in accordance with a change in the gas supply amount to maintain an air-fuel ratio at an optimum value. , Trying to maintain good combustion. Here, it is conceivable to perform air-fuel ratio control so as to keep the air supply amount constant by keeping the rotation speed of the blower fan constant with respect to the gas supply amount, which is effective for fluctuations in the power supply voltage. . However, if the air supply / exhaust resistance changes due to the occurrence of clogging of the air supply / exhaust system, etc., even if the rotation speed of the air blower fan is constant, the air flow rate changes and the air supply volume is affected.
The combustion state may deteriorate. Therefore, incomplete combustion may occur.

An example of a conventional technique for preventing such a problem is disclosed in Japanese Patent Laid-Open No. 62-255723. In the combustion device disclosed in the same publication, instead of maintaining the rotation speed of the blower fan constant, control is performed to keep the drive current of the motor constant. As a modification of this technique, there is a control in which the drive voltage or the drive power is constant instead of the drive current of the motor.

Further, Japanese Patent Application Laid-Open No. 2-146412 discloses another combustion device. The device disclosed in the same publication detects the drive current of the motor of the blower fan while performing control to keep the rotation speed of the blower fan constant, and issues an alarm when the current value reaches a predetermined abnormal value. It is a thing. By such an alarm, the user can be informed of the fact that the blower fan cannot continue to be used and can take appropriate measures.

[0005]

However, each of the conventional combustion devices described above has the following problems. First, problems of the combustion device disclosed in Japanese Patent Laid-Open No. 62-255723 will be described. In this combustion apparatus, although the change in the air amount is suppressed by the current control, the air amount after the control is not completely equal to the original air amount. Therefore, good combustion is maintained by this control only when the degree of change in the blowing characteristics is small. Therefore, when the degree of blockage of the air supply / exhaust system is large, even if this control is performed, the amount of air is still insufficient, and the combustion operation can be continued without a good combustion condition, resulting in incomplete combustion. We cannot rule out fear.
Further, when the supply air temperature changes, the air density also changes and affects the air amount, but since such an effect is not taken into consideration, an error may occur due to air temperature, combustion heat, heat generation of the motor, or the like.

A problem with the control for keeping the drive voltage of the motor constant is that, when the load of the blower fan is lightened, the current decreases, so that the variation range of the fan rotation speed is reduced. Can not be secured sufficiently. Further, as a problem in the case where the control for keeping the driving power of the motor constant is performed, since the winding resistance value of the motor changes with the temperature rise due to Joule heat, the influence thereof appears as the fluctuation of the rotation speed. Is mentioned. Therefore, only by controlling the driving power source of the motor, even if the current, voltage or power is controlled, the sufficient effect cannot be obtained.

Next, problems of the combustion device disclosed in Japanese Patent Laid-Open No. 2-1446412 will be described. As described above, this combustion device issues an alarm when the drive current of the motor reaches an abnormal value, and the abnormal value is a predetermined value. On the other hand, the drive current when the motor is operating normally has individual differences even within the same model, and also varies depending on the mounting condition of the air supply / exhaust system, etc., and is not constant. For this reason, there are cases where the alarm is issued even if the drive current of the motor is slightly deviated from the initial value and cases where the alarm is not issued even when the drive current is considerably deviated from the initial value. In the former case, the user is forced to perform work such as useless inspection, and in the latter case, the combustion operation in a bad combustion state is continued and incomplete combustion occurs. Further, even in this combustion device, the influence of the supply air temperature is not taken into consideration, and an error occurs due to the temperature, combustion heat, heat generation of the motor, or the like.

The present invention has been made in order to solve the above problems of the prior art, and its object is to detect the fluctuation of the load of the blower fan due to the clogging of the air supply / exhaust system. The combustion device is designed to prevent deterioration of the combustion state by judging the degree of clogging in the supply / exhaust system, performing appropriate combustion control, and adding corrections due to changes in the supply air temperature. To provide.

[0009]

In order to achieve this object, a combustion device (1) of the present invention is a combustion device comprising a burner and a blower fan for supplying combustion air to the burner. Comparing the fan rotation speed detection means for detecting the rotation speed of, and the fan rotation speed detected by the fan rotation speed detection means with a reference rotation speed when the blower fan is driven with a constant drive current in the initial stage of use, A clogging degree determining means for determining the supply / exhaust clogging degree, and a control for stopping the combustion of the burner or reducing the combustion amount when the clogging degree for the supply / exhaust degree determined by the clogging degree determining means exceeds a predetermined reference value. Combustion control means for performing, the clogging degree determination means, driving the blower fan with the same drive current as when the reference rotation speed is measured, and compares the rotation speed with the reference rotation speed. It is configured to be a butterfly.

Further, the combustion device (2) of the present invention is a combustion device comprising a burner and a blower fan for supplying combustion air to the burner, the fan rotation speed detection detecting the rotation speed of the blower fan. Means and the fan rotation speed detected by the fan rotation speed detection means with a reference rotation speed when the blower fan is driven with a constant drive current in the initial stage of use to determine the degree of clogging of air supply and exhaust. Means and a blower control means for controlling to increase the rotation speed of the blower fan when the supply / exhaust clogging degree judged by the clogging degree judging means exceeds a predetermined reference value. The fan is driven with the same drive current as when the reference rotation speed is measured, and the rotation speed is compared with the reference rotation speed.

Further, the combustion apparatus (3) of the present invention comprises: a supply air temperature detecting means for detecting the temperature of the combustion air supplied to the burner; and a fan rotation speed detected by the fan rotation speed detecting means. The configuration of (1) or (2) is provided, further comprising: a fan rotation speed correction unit that corrects based on the temperature detected by the supply air temperature detection unit. Further, in the combustion device (4) of the present invention, the correction formula by the fan rotation speed correction means is as follows: N ′ = K × N (N ′ is the corrected rotation speed, K is the temperature detected by the supply air temperature detection means) And N is the number of revolutions before correction).

[0012]

According to the combustion apparatus (1) of the present invention having such a configuration, the clogging degree determining means drives the blower fan with a constant drive current at the initial stage of use, and the fan rotation speed detecting means causes the blower fan to operate. Measure the reference speed. After that, the clogging degree determination means drives the blower fan with the same drive current as when the reference rotation speed is measured, and compares the rotation speed at that time with the reference rotation speed to judge the supply / exhaust clogging degree. When the supply / exhaust clogging degree exceeds a predetermined reference value, the combustion control means performs control to stop the combustion of the burner or reduce the combustion amount to prevent deterioration of the combustion state. Further, according to the combustion apparatus (2) of the present invention, when the supply / exhaust clogging degree exceeds a predetermined reference value, the blower control means performs control to increase the rotation speed of the blower fan to prevent deterioration of the combustion state.

According to the combustion device (3) of the present invention,
The supply air temperature detection means detects the temperature of the combustion air supplied to the burner, and the fan rotation speed correction means corrects the fan rotation speed based on the temperature. Further, according to the combustion device (4) of the present invention, the fan rotation speed correction means is: N ′ = K × N (N ′ is the corrected rotation speed, and K is determined by the temperature detected by the supply air temperature detection means. The coefficient, N is the number of revolutions before correction) is used to correct the number of revolutions of the fan.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which the combustion apparatus of the present invention is embodied as a gas water heater will be described in detail below with reference to the drawings.
FIG. 1 shows the basic configuration of the gas water heater according to this embodiment. This gas water heater burns the fuel gas supplied from the gas supply pipe 12 in the gas burner 1 in the combustion pot 11, and heats the water flowing through the heat exchanger 10 by the combustion heat.
The combustion pot 11 is provided with a blower fan 2 for supplying combustion air to the gas burner 1, and the gas supply pipe 12 is provided with a proportional valve 13 for adjusting the supply amount of fuel gas. The blower fan 2 is provided with a rotation speed detector 3 that detects a fan rotation speed and a temperature sensor 4 that detects a supply air temperature of the blown air. Also, the blower fan 2 is
It is driven by a fan driving device 5 including a power source and the like.

The detected values of the rotation speed detector 3 and the temperature sensor 4 are controlled by the controller 6 which controls the combustion state of the gas burner 1.
Is input to The controller 6 includes a CPU 7 and a ROM
8, a RAM 9 and the like, which adjusts the heating power by adjusting the amount of fuel gas supplied to the gas burner 1 and also adjusts the amount of air blown to maintain an air-fuel ratio that provides a good combustion state. Take control. Therefore, the controller 6 outputs a drive signal to the fan drive device 5 and the proportional valve 13. Further, the CPU 7 has a timer function of measuring the elapsed time after the combustion in the gas burner 1 is stopped. The ROM 8 stores programs for performing general combustion control of the gas burner 1 as well as programs for determining the degree of clogging of the air supply / exhaust system from the fan rotation speed and the like to maintain a good combustion state. Has been done. As shown in the graph of FIG. 4, the fan drive device 5 applies a drive current I to the blower fan 2 in accordance with a control amount C (voltage, PWM, etc.) input from the controller 6.

Next, the operation of the gas water heater having the above construction will be described. In this gas water heater, as described above, control is performed to maintain the combustion state of the gas burner 1 in a good condition. This is because, in the gas water heater, the air supply / exhaust system is clogged during use and the ventilation characteristics change, and if the gas water heater is used as it is, the air-fuel ratio is affected and the combustion state deteriorates. Therefore, the degree of clogging of the air supply / exhaust system is determined, and the gas supply amount and the air flow amount are controlled according to the result. Hereinafter, FIG.
This routine will be described with reference to the flowchart of FIG.

First, step (hereinafter referred to as "S") 1
At, the fan driving device 5 drives the blower fan 2 with a preset constant current. Then, when the rotation of the blower fan 2 becomes stable, the rotation speed is detected by the rotation speed detector 3 in S2. The number of rotations detected here serves as a criterion for determining the degree of clogging. At that time, the temperature sensor 4 also detects the supply air temperature (S3). Then, in S4, the rotation speed detected in S2 is corrected based on the supply air temperature detected in S3. This is because the density of air changes when the supply air temperature changes, and the rotation speed of the blower fan 2 changes even if the drive current is constant. A specific method of such correction will be described later.

Then, in S5, it is determined whether or not the first clogging degree determination routine is executed after the gas water heater is installed. If it is determined that it is the first time (S
5: Yes), and proceed to S6. In S6, the rotation speed detected in S2 and corrected in S4 is used as the initial rotation speed for RA.
Store in M9. This is because it is used as a reference rotation speed for subsequent rotation speed measurement. Then, in this case, the routine ends by determining the initial rotation speed. When the routine ends, the normal combustion control is performed.

If it is determined in S5 that it is not the first time (S5: No), the process proceeds to S7. In S7, S
The rotation speed detected in 2 and corrected in S4 is compared with the initial rotation speed stored in the RAM 9. The initial number of revolutions, which is used as a reference for comparison, is stored in S6 during the initial measurement. This comparison is performed in order to determine the degree of clogging of the air supply / exhaust system from the change in the rotational speed by driving the blower fan 2 with the same drive current as in the first measurement. That is, when the air supply / exhaust system is clogged and the ventilation resistance increases, the amount of air blown decreases, so the load of the blower fan 2 decreases and the number of rotations at the same drive current increases. This is shown in the graph of FIG. In other words, S7
Is a process for knowing ΔN in the graph of FIG.

Next, in S8, it is determined whether or not the amount of change in the number of revolutions is within a predetermined range, that is, ΔN is a predetermined value or less. This is because it is necessary to determine whether ΔN is large enough to change the combustion condition of the gas burner 1. The predetermined value of ΔN here may be stored in advance in the ROM 8 or may be set by the user. If ΔN is less than or equal to a predetermined value (S
8: Yes), the amount of change in the number of revolutions is small, and the gas burner 1
Since the combustion state is good without changing the combustion condition of, the routine ends. This is when the degree of clogging of the air supply / exhaust system is still small. When the routine ends, the normal combustion control is performed.

If ΔN exceeds the predetermined value in S8 (S8: No), the process proceeds to S9. ΔN in S9
Is greater than a predetermined limit value. This is because, if the amount of change in the number of revolutions is too large, the clogging of the air supply / exhaust system remarkably progresses and the combustion state cannot be improved even if the combustion conditions of the gas burner 1 are changed. The limit value here may be stored in advance in the ROM 8,
It may be set by the user.

If ΔN is less than or equal to the limit value (S9:
No), and proceeds to S10. In S10, the combustion conditions are changed to improve the combustion state. The change of the combustion condition is to cope with the decrease in the blowing amount of the combustion air to the gas burner 1 due to the clogging of the supply / exhaust system to achieve combustion with a good air-fuel ratio. Therefore, specifically, a change to reduce the supply amount of the fuel gas to the gas burner 1 by, for example, about 10%,
Alternatively, the amount of air blown by the blower fan 2 may be increased by, for example, about 10%. The changed combustion conditions are stored in the RAM 9 of the controller 6 and are applied from the next time the normal combustion control is performed. Thus, the routine ends and the normal combustion control is performed.

When ΔN is larger than the predetermined limit value in S9 (S9: Yes), the process proceeds to S11. In this case, the combustion condition is not within the range in which the combustion condition can be improved by changing the combustion condition. Therefore, the abnormality is displayed and the user is notified of the fact, and the routine is ended. Therefore, in this case, the normal combustion control is not performed, and the combustion is not performed until the work for removing the clogging of the supply / exhaust system is performed thereafter. This is because there is a high possibility that incomplete combustion will occur because the combustion state is not good even if it burns.
The above is the flow of the clogging degree determination routine.

The timing at which the clogging degree determination routine should be performed is previously incorporated in a normal combustion control routine. This is because the clogging of the air supply / exhaust system progresses during normal combustion, so it is preferable to check it periodically. The overall combustion control including the timing at which the clogging degree determination routine should be performed will be described with reference to the flowchart of FIG. In the gas water heater of this embodiment, the presence or absence of water flow in the heat exchanger 10 is constantly monitored (S2).
1). When the water flow is detected (S21: Yes), the clogging degree determination routine is first executed before the combustion operation (S22). In general, a predetermined pre-purge operation is performed before ignition of the gas burner 1. Therefore, if the clogging degree is judged at this time, the clogging degree can be judged without affecting the original combustion of the gas burner 1.

When the determination of the degree of clogging is completed, the result of S9 is Yes.
Unless it is determined that the clogging degree exceeds the limit value, the routine proceeds to S23, where normal combustion control is performed. That is, in S23, by the controller 6,
The gas burner 1 is controlled by controlling the proportional valve 13 and the blower fan 2.
To burn fuel gas. At this time, the opening degree of the proportional valve 13 and the rotation speed of the blower fan 2 follow the changed conditions when the combustion conditions are changed in the clogging degree determination routine of S22. During the normal combustion, the water flow in the heat exchanger 10 is constantly monitored (S24). When the stop of the water flow is detected (S24: Yes), the process proceeds to S25 and the combustion in the gas burner 1 is stopped. Thus, the combustion control routine ends. In the gas water heater of this embodiment that performs such combustion control, the degree of clogging is confirmed immediately before combustion (S
22), there is an advantage that it can be operated in a good combustion state.

Next, the rotation speed correction performed in S4 in the flow of FIG. 2 will be described. This correction is performed in order to eliminate this influence because the air density changes when the supply air temperature changes, and the rotation speed of the blower fan 2 changes even when the drive current is constant. In this correction, N ′ = K × N (1) is used as a correction formula. Here, N is the rotation speed before correction, which is the value detected by the rotation speed detector 3 in S2 in the flow of FIG. K is a correction coefficient determined by the temperature detected by the temperature sensor 4, and N ′ is the corrected number of revolutions. Figure 6
The graph shows the outline.

In FIG. 6, when T = 25 (° C.), K =
It shows that it is 1. In this example, the temperature is 25 ° C.
This is because the reference temperature is. Further, FIG. 6 shows that K increases as T increases and K decreases as T decreases. When the air supply temperature is higher than the reference temperature, the air density decreases, and the actual air flow rate is small compared to the rotation speed of the blower fan. Because it will be. The opposite is true when the supply air temperature is lower than the reference temperature. Therefore, returning to the equation (1), when the supply air temperature is higher than the reference temperature, the correction coefficient K smaller than 1 is multiplied by the rotation speed N to correct the overestimation of the air flow, and the supply air temperature is lower than the reference temperature. At times, a correction coefficient K larger than 1 is multiplied by the number of revolutions N to correct the underestimation of the blown air amount. Thus, the number of revolutions corresponding to the actual air flow rate can be calculated regardless of whether the supply air temperature is high or low, and the clogging degree can be accurately measured.

Next, a second embodiment will be described. The gas water heater of this embodiment has substantially the same configuration and operation as those of the above-described embodiments, but the timing of performing the clogging degree determination routine in the combustion control routine is different. The combustion control routine of this gas water heater is shown in the flowchart of FIG. This flow will be described in comparison with the flow of FIG. In the flow of FIG. 7, when the water flow in the heat exchanger 10 is detected and it is determined to be Yes in S21, the routine proceeds to S23 without performing the clogging degree determination routine, and normal combustion control is performed. This is different from the flow of FIG. 3 in which the clogging degree determination routine is executed in S22 and then the process proceeds to S23. The process from S23 to S25 is the same as the flow in FIG.

When the combustion of the gas burner 1 is stopped in S25, the routine proceeds to S28, where a clogging degree judgment routine is performed, and then the combustion control routine is ended. This is because if the clogging degree determination routine is executed during a predetermined post-purge operation performed after the gas burner 1 is extinguished, the clogging degree can be determined without affecting the original combustion of the gas burner 1. This is different from the flow of FIG. 3 in which the combustion control routine ends immediately after the combustion is stopped in S25. When the combustion condition is changed in the clogging degree determination routine of S28, the changed combustion condition is applied from the next time normal combustion is performed. In the gas water heater of the second embodiment that performs such combustion control, the state in which the degree of clogging has progressed due to the combustion in S23 is measured, and particularly when the degree of clogging exceeds the limit value, S11 in FIG.
There is an advantage that the user can recognize that it is necessary to immediately display the abnormality display and clean the air supply / exhaust system before the next use.

Next, a third embodiment will be described. The gas water heater of this embodiment has substantially the same configuration and operation as those of the second embodiment, but is clogged after a predetermined time has elapsed after performing normal combustion in the combustion control routine. A degree judgment routine is performed. The combustion control routine of this gas water heater is shown in the flowchart of FIG. This flow will be described in comparison with the flow of FIG. The flow of FIG. 8 is the same as the flow of FIG. 7 from the start of the combustion operation until the combustion is stopped in S25.

When the combustion is stopped in S25, S
The clock starts at 26. Then, after a lapse of a predetermined waiting time (S27: Yes), the process proceeds to S28 and the clogging degree determination routine is executed. This is for avoiding a time period when the entire apparatus is at a high temperature immediately after extinguishing the gas burner 1 and determining the degree of clogging after the temperature has dropped. This is different from the flow of FIG. 7 in which the clogging degree determination routine is performed in S28 immediately after the combustion is stopped in S25. The reason for determining the degree of clogging after the temperature has dropped is that the temperature of the intake air itself is corrected as described in FIG. 6, but the winding resistance of the motor and the permanent magnet This is because measurement at room temperature is ideal in consideration of changes in magnetomotive force. Although the execution timing of the clogging degree determination routine is different in each of the above-described embodiments, which one is selected is set in advance when the gas water heater is installed. Alternatively, the setting can be changed after installation.

As described above in detail, in the combustion apparatus according to each of the above-described embodiments, the blower fan 2 is driven with the same drive current as the reference rotation speed when the blower fan 2 is first driven with a constant current. If the degree of clogging of the air supply / exhaust system, which is determined by comparing with the fan rotation speed at that time, exceeds the predetermined range, the combustion conditions from the next time onward are changed.
Even if the degree of clogging progresses, a combustion state with a good air-fuel ratio is maintained. Also, if the degree of clogging exceeds the specified limit value, an error is displayed and combustion is not started from the next time, so incomplete combustion is prevented and the user recognizes the necessity of cleaning. it can. In addition, we decided to determine the degree of clogging by correcting the fan speed with the air supply temperature.
The degree of clogging can be determined with high accuracy regardless of changes in the air density due to high or low temperatures.

Further, since the clogging degree is judged at the time of pre-purge before the normal combustion control or at the post-purge after the usual combustion control, the clogging degree can be judged without affecting the original combustion of the gas burner 1. In addition, since the degree of clogging is determined after a predetermined time has elapsed after extinguishing the gas burner 1, it is possible to perform measurement without the influence of the device temperature. Thus, a combustion device that prevents deterioration of the combustion state is realized. The embodiments do not limit the present invention in any way, and various modifications and improvements are possible without departing from the spirit of the present invention. For example,
The controller 6 includes an EPROM in addition to the RAM 9,
You may make it memorize | store the initial rotation speed of the ventilation fan 2, the combustion conditions after the change of the gas burner 1, etc. in this. Further, the clogging degree determination routine does not have to be executed every time each combustion, and may be executed, for example, every 50 times of use.

[0034]

As is apparent from the above description, in the combustion apparatus of the present invention, the clogging degree of the air supply / exhaust system is determined by the fluctuation of the rotation speed from the initial value when the blower fan is driven with a constant current. Therefore, when the degree of clogging is above a certain level, the combustion conditions can be changed to maintain combustion at a good air-fuel ratio and prevent the occurrence of incomplete combustion or the like. Further, if the degree of clogging exceeds a predetermined limit value, combustion is stopped so that incomplete combustion does not occur. Further, in the combustion apparatus of the present invention, since the supply air temperature is detected and the rotation speed of the blower fan is corrected, the clogging degree can be determined with high accuracy regardless of whether the supply air temperature affects the air density. It Therefore, it is possible to provide a combustion device that eliminates the possibility of incomplete combustion, and its industrial effect is great.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a combustion device according to an embodiment.

FIG. 2 is a flowchart of a clogging degree determination routine.

FIG. 3 is a flowchart of control of a combustion device.

FIG. 4 is a graph showing a relationship between a control amount and a fan current in the fan driving device.

FIG. 5 is a graph showing the relationship between the degree of clogging and the fan rotation speed in a combustion device.

FIG. 6 is a graph showing the relationship between the supply air temperature and the correction coefficient.

FIG. 7 is a flow chart of control of a combustion device according to a second embodiment.

FIG. 8 is a flow chart of control of a combustion device according to a third embodiment.

[Explanation of symbols]

 1 gas burner 2 blower fan 3 rotation speed detector 4 temperature sensor 5 fan drive device 6 controller 7 CPU 13 proportional valve

Claims (4)

[Claims] 1. A combustion device comprising a burner and a blower fan for supplying combustion air to the burner, wherein a fan rotation speed detecting means for detecting a rotation speed of the blower fan, and a fan rotation speed detecting means for detecting the rotation speed. The fan rotation speed was compared with the reference rotation speed when the blower fan was driven with a constant drive current in the initial stage of use, and the clogging degree judgment means for judging the supply / exhaust clogging degree, and the clogging degree judgment means were judged. When the air supply / exhaust clogging degree exceeds a predetermined reference value, the combustion of the burner is stopped,
Or a combustion control means for performing control for reducing the combustion amount, wherein the clogging degree determination means drives the blower fan with the same drive current as when the reference rotation speed is measured to set the rotation speed to the reference rotation speed. Combustion device characterized by comparing with the number. 2. A combustion device comprising a burner and a blower fan for supplying combustion air to the burner, wherein a fan rotation speed detecting means for detecting a rotation speed of the blower fan and a fan rotation speed detecting means for detecting the rotation speed. The fan rotation speed was compared with the reference rotation speed when the blower fan was driven with a constant drive current in the initial stage of use, and the clogging degree judgment means for judging the supply / exhaust clogging degree, and the clogging degree judgment means were judged. And a blower control means for controlling to increase the rotation speed of the blower fan when the supply / exhaust clogging degree exceeds a predetermined reference value, and the clogging degree determination means is the same as when the blower fan measures the reference rotation speed. The combustion device is driven by the driving current of 1 to compare the rotation speed with the reference rotation speed. 3. A supply air temperature detecting means for detecting a temperature of combustion air supplied to a burner, and a fan rotation speed detected by the fan rotation speed detecting means are detected by the supply air temperature detecting means. The combustion device according to claim 1 or 2, further comprising: a fan rotation speed correction unit that performs correction based on temperature. 4. The correction formula by the fan rotation speed correction means is: N ′ = K × N (N ′ is the corrected rotation speed, K is a coefficient determined by the temperature detected by the supply air temperature detection means, and N is correction 4. The combustion device according to claim 3, wherein the combustion speed is the previous rotation speed.