JP2000213738A - Combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately sense the insufficiency of a combustion oxygen even if an ambient temperature of a thermocouple is changed by stopping combustion of a burner when an output voltage of a correcting voltage becomes a reference voltage or below decided based on a voltage held at a stable voltage holding means. SOLUTION: A correcting voltage output means 42 fictionalizes an actual room temperature as an ambient temperature of a thermocouple 20, and calculates a correcting voltage corrected by a predetermined formula from the output voltage of the thermocouple 20. A stable voltage holding means 43 holds the correcting voltage output from the means 42 in a memory 46 when a combustion of a burner 4 is stabilized. An oxygen deficiency monitoring means 44 selects a reference stable voltage held in the memory 46 in response to a combustion amount of the burner 4 during combustion of the burner 4, judges that a combustion oxygen becomes a deficient state when the correcting voltage output from the means 42 is lowered to a predetermined level or below from the stable voltage, and oxygen monitor processes for forcibly stopping the combustion of the burner 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for monitoring the shortage of combustion oxygen generated during combustion of a burner and stopping the combustion of the burner when the combustion oxygen becomes insufficient.

[0002]

2. Description of the Related Art Conventionally, in a combustion apparatus having a burner such as a gas fan heater, a thermocouple is provided in the vicinity of the burner, and a voltage output from the thermocouple during combustion of the burner is set to a predetermined reference voltage. It is known to monitor the shortage of the combustion oxygen of the burner by comparing with the above. When a burner is burned by providing a thermocouple in this manner, the output voltage of the thermocouple decreases as the oxygen concentration in the room where the combustion device is placed decreases. Therefore, when the output voltage of the thermocouple becomes lower than the predetermined reference voltage during combustion of the burner, it is determined that the combustion oxygen has become insufficient, and the combustion of the burner is stopped. Burning of the burner is continued in this state, so that incomplete combustion of the burner can be prevented.

However, the relationship between the output voltage of the thermocouple during burner combustion and the oxygen concentration in the room changes depending on the relationship between the mounting position of the thermocouple and the burner, the aging of the thermocouple, and the like.
For this reason, when the reference voltage is set to a fixed value, it may not be possible to accurately detect that oxygen for combustion has become insufficient.

The inventors of the present invention have invented a combustion apparatus that determines the reference voltage based on the output voltage of a thermocouple when the combustion state of the burner is stabilized after ignition of the burner (Japanese Patent No. 2677478). ). According to this prior invention, the reference voltage is determined to be a voltage lower than the output voltage of the thermocouple when the combustion state of the burner is stabilized by a predetermined level. The shortage of oxygen for combustion can be accurately detected by eliminating the influence of the secular change of the pair.

However, the present inventors determined the reference voltage based on the output voltage of a thermocouple in a state where, for example, the room is ventilated and the temperature of the room where the combustion device is placed is lowered. At times, it has been found that when the room temperature subsequently rises, a deficiency of combustion oxygen may be erroneously detected.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned background, and it has been found that even when the ambient temperature of a thermocouple changes, the output voltage of the thermocouple causes a shortage of oxygen for combustion. It is an object of the present invention to provide a combustion device that can accurately detect the combustion.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and includes a burner, a thermocouple for outputting a voltage corresponding to a combustion state of the burner, and a thermocouple around the thermocouple. Ambient temperature detecting means for detecting a temperature, correction voltage output means for outputting a voltage obtained by correcting the output voltage of the thermocouple according to a difference between the detected temperature of the ambient temperature detecting means and a predetermined reference temperature, and the burner After the start of combustion, the stable voltage holding means for holding the output voltage of the correction voltage output means when the combustion state of the burner is stabilized; and the output voltage of the correction voltage output means after the combustion state of the burner is stabilized. However, when the voltage becomes equal to or lower than a reference voltage determined based on the voltage held by the stable voltage holding means, it is determined that the combustion oxygen is insufficient, and the burner burnout is stopped. I do Characterized in that a missing monitoring means.

[0008] The output voltage of the thermocouple is determined by a contact (temperature measuring contact) on the combustion flame side of the burner, which is an object to be measured, and a contact (cooling circuit board) on a means (measurement circuit board or the like) for processing the output voltage. (Contact point). Therefore, if the temperature of the cold junction is kept constant, the temperature of the temperature measuring junction can be detected stably from the output voltage of the thermocouple. When the combustion oxygen of the burner is insufficient, the combustion flame of the burner extends upward, the temperature of the flame to which the thermocouple is exposed decreases, and the output voltage of the thermocouple decreases. Therefore, by monitoring the output voltage of the thermocouple, shortage of oxygen for combustion can be detected.

However, for example, in a gas fan heater, when the combustion of the gas burner is continuously performed, a notification for urging the user to ventilate the room every predetermined time (for example, one hour) is provided. Yes, if the user ventilates the room in response to the notification, the room temperature drops rapidly. And
After the end of the ventilation, the room temperature gradually rises due to heat radiation from the gas fan heater. Thus, when the room temperature fluctuates, the temperature around the thermocouple fluctuates accordingly,
The temperature of the cold junction of the thermocouple also fluctuates. In this case, since the output voltage of the thermocouple fluctuates under the influence of a change in ambient temperature, which is an element other than the original detection target, that is, lack of combustion oxygen, it is necessary to accurately detect the lack of combustion oxygen. May not be performed, and erroneous detection of insufficient oxygen for combustion may occur.

For example, a reference voltage for detecting a shortage of oxygen for combustion is determined based on an output voltage of the thermocouple in a state where the ambient temperature of the thermocouple is low, and thereafter, the thermocouple is radiated by a gas burner. When the ambient temperature of the pair increases, erroneous detection of insufficient oxygen for combustion may occur.
That is, when the temperature of the cold junction of the thermocouple increases with the increase of the ambient temperature, the temperature difference between the temperature measuring junction and the cold junction of the thermocouple decreases. Therefore, regardless of the degree of shortage of oxygen for combustion, the output voltage of the thermocouple decreases to be equal to or lower than the reference voltage, and although oxygen shortage for combustion does not actually occur, oxygen shortage for combustion is insufficient. There is a possibility that the state is erroneously detected.

Therefore, in the present invention, the output voltage of the thermocouple, which is output from the correction voltage output means, is not directly used, and the output voltage of the thermocouple detected by the ambient temperature detection means is not directly used. A shortage of oxygen for combustion is detected using a voltage corrected according to a difference between the temperature and the reference temperature. That is, the oxygen deficiency monitoring means determines the reference voltage based on the output voltage of the correction voltage output means, and when the output voltage of the correction voltage output means becomes equal to or less than the reference voltage, the oxygen for combustion is reduced. It is determined that the state has become insufficient. Thereby, even when the ambient temperature of the thermocouple fluctuates, the influence of the fluctuation can be eliminated and the shortage of the oxygen for combustion can be accurately detected, and the erroneous detection of the shortage of the oxygen for combustion can be performed. Can be prevented.

Further, the combustion device is a heater having room temperature detecting means for detecting room temperature, wherein the room temperature detecting means is used as the ambient temperature detecting means.

Since the measurement circuit to which the cold junction of the thermocouple is connected is weak to heat, it is usually provided at a place where it is hardly affected by the heat generated by the burner. Therefore, the ambient temperature of the thermocouple is close to room temperature. Therefore, the room temperature detecting means is diverted as the ambient temperature detecting means, and the correction voltage output means corrects the output voltage of the thermocouple based on the detected temperature of the ambient temperature detecting means, thereby newly adding the ambient temperature. It is not necessary to provide the detection means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 is an overall configuration diagram of a hot air heater as a combustion device of the present invention, FIG. 2 is a control block diagram of the hot air heater shown in FIG. 1, and FIGS. 3 to 5 are control units of the control unit shown in FIG. 4 is an operation flowchart of a combustion control unit.

Referring to FIG. 1, a hot air heater according to the present embodiment is a gas fan heater, and includes a duct 2, a blower fan 3, and a gas burner 4 in a main body case 1 disposed indoors.
(Corresponding to a burner of the present invention), an air supply duct 5, a gas supply pipe 6, and a control unit 7.

The duct 2 constitutes an air passage for hot air. An air inlet 8 for taking in room air is opened at the back of the main body case 1, and a hot air outlet is provided at a lower front part of the main body case 1. 9 is open. In order to prevent dust and dirt from flowing into the duct 2, the air filter 1
0 is detachably attached. A movable louver 11 for adjusting the opening degree is attached to the outlet 9,
Geared motor 1 for driving this movable louver 11
2 are provided.

The blower fan 3 has a fan motor 14 whose rotation speed changes in proportion to the magnitude of the supplied current, and rotating blades 15 arranged in the duct 2 facing the air outlet 9 and driven to rotate by the fan motor 14. And the room air s is sucked into the duct 2 from the intake port 8 by the rotation of the rotary blade 15. Then, the sucked room air s is mixed with the combustion exhaust gas h of the gas burner 4 incorporated in the duct 2 and blown out as warm air m from the outlet 9 into the room. The blower fan 3 is provided with a rotation speed sensor 16 (comprising a Hall element or the like) for detecting the rotation speed of the fan motor 14, and the rotation speed sensor 16 outputs a signal corresponding to the rotation speed of the fan motor 14. Is output to the control unit 7.

An ignition electrode 19 for igniting a mixture of combustion air and fuel gas is disposed downstream of the gas burner 4 incorporated in the duct 2. It is discharged into the duct 2. Also,
A thermocouple 20 for detecting a state of a combustion flame is disposed downstream of the gas burner 4. The thermocouple 20 generates an electromotive force in a state where the thermocouple is exposed to the combustion flame of the gas burner 4, and outputs the electromotive force to a control unit. 7 is output.

The air supply duct 5 is a passage for supplying room air s (combustion air) and fuel gas to the gas burner 4, and communicates the gas burner 4 with the combustion cylinder 17 and defines the duct 2. And has an intake port 21 for room air s which is incorporated in the main body case 1 and opened at the back of the main body case 1. A nozzle 22 attached to the tip of the gas supply pipe 6 is provided at a position on the gas burner 4 side of the air supply duct 5. Room air s is sucked into the air supply duct 5 from the air inlet 21 by the rotation of the blower fan 3.
The sucked room air s is supplied to the nozzle 22 of the gas supply pipe 6.
And the mixture is supplied to the gas burner 4. In addition, the intake port 21 is connected to the duct 2
Together with an air filter 8.

A room temperature thermistor 13 (corresponding to the ambient temperature detecting means and the room temperature detecting means of the present invention) is attached to a location near the air inlet 21 inside the air supply duct 5 so as to face the air inlet 21. The room temperature thermistor 13 outputs a signal corresponding to the room temperature to the control unit 7.

The gas supply pipe 6 is provided with electromagnetic valves 24 and 25 and an electromagnetic proportional valve 26 in this order from the upstream side. The solenoid valves 24 and 25 are opened by energization from the control unit 7, and when the energization is stopped, they are closed to shut off the passage of fuel gas. The electromagnetic proportional valve 26
Since the opening degree of the valve increases with the magnitude of the current supplied from the control unit 7, the magnitude of the supplied current is proportional to the amount of gas supplied to the gas burner 4.

An operation switch 2 is provided on the outer surface of the main body case 1.
7, a room temperature setting switch 28, a ventilation lamp 29, a filter lamp 30, and a buzzer 31 are provided. Also,
The operation switch 27 has a built-in lamp 32 (see FIG. 2). The operation switch 27 is turned ON / O by the user.
The start and end of the heating operation are instructed to the control unit 7 according to the FF operation. The lamp 32 incorporated in the operation switch 27 is turned on, blinks, and turned off according to the operation state of the gas fan heater. The room temperature setting switch 28 is an operation switch for setting a room temperature desired by the user.
By its predetermined operation, it instructs the control unit 7 of the temperature control target temperature T _A of the gas fan heater for example 1 ℃ by raised or is lowered.

When the duration of the combustion operation of the gas fan heater reaches one hour, the ventilation lamp 29 is turned on by the energizing process of the control unit 7, and this lighting prompts the user to ventilate the room. When the clogging of the air filter 10 is progressing or the like, the filter lamp 29
When the air volume at the time of the rotation operation becomes smaller to some extent as compared with the normal case, the light is turned on by the control of energization of the control unit 7, and the light notifies the user of the necessity of cleaning the air filter 10 or the like. . The buzzer 31 is connected to the ventilation lamp 29
At the time of turning on the filter lamp 30 or the like, a sound is generated by energization from the control unit 7 to draw the user's attention.

The overheat prevention thermistor 33 detects that the internal temperature of the gas fan heater has risen abnormally due to poor combustion of the gas burner 4, etc., and the control unit 7 controls the overheat prevention thermistor 33. When it is detected from the detected temperature that the internal temperature of the gas fan heater has risen abnormally, the combustion of the gas burner 4 is stopped to protect the gas fan heater.

Next, referring to FIG.
Is constituted by using a CPU, a ROM, a RAM, and the like.
And a fan control unit 41 that controls the blower fan 3.

The combustion control unit 40 ignites, extinguishes, and burns the gas burner 4 based on the instruction signals of the operation switch 27 and the room temperature setting switch 28, and the temperature detection signals of the room temperature thermistor 13, the overheat prevention thermistor 33 and the thermocouple 20. Combustion control of the gas burner 4 such as adjustment of the amount (adjustment of the supply amount of fuel gas by the electromagnetic proportional valve 26 and adjustment of the supply amount of combustion air by the fan motor 14 via the fan control unit 41) is performed. In the present embodiment, the combustion control unit 40
Controls the combustion amount of the gas burner 4 in three stages (strong combustion, medium combustion, and weak combustion) during the combustion operation including the ignition operation of the gas burner 4.

A correction voltage output provided in the combustion control unit 40
The means 42 is used for detecting the actual temperature detected by the room temperature thermistor 13.
Room temperature T_RIs assumed to be the ambient temperature of the thermocouple 20, and the detection chamber
Warm T _RAnd the reference temperature T_B(For example, 22 ° C)
And the output voltage V of the thermocouple 20 _TCBy the following equation (1)
Corrected correction voltage V_TC22Is calculated, and the correction voltage V_TC22To
Output to the stable voltage holding means 43 and the oxygen deficiency monitoring means 44.

V _TC22 = V _TC −A (T _B −T _R ) (1) Here, A is a correction coefficient determined by experiments or the like in accordance with the specifications of the combustion apparatus. Further, 22 ° C. which is set as the reference temperature T _B is the temperature that assumes that there is a high frequency set by room temperature setting switch 28. By this correction, the output voltage V _TC thermocouple 20 is converted room temperature when it is assumed that a reference temperature T _B, which is the output voltage of the thermocouple 20 to the correction voltage V _TC22.

After the start of combustion of the burner 4, when the combustion of the burner 4 becomes stable in the strong combustion, the medium combustion, and the weak combustion, the stable voltage holding means 43 outputs the correction output from the correction voltage output means 42. The voltage V _TC22 is stored in the memory 46 as a strong combustion stable voltage V _S , a medium combustion stable voltage V _M , and a weak combustion stable voltage V _W , respectively.

During the combustion of the burner 4, the oxygen deficiency monitoring means 44 controls the strong combustion stable voltage V _S , medium stored in the memory 46 according to the amount of combustion (strong combustion, medium combustion, weak combustion) of the burner 4. One of the stable combustion voltage V _M and the weak stable combustion voltage V _W is selected as the reference stable voltage V _B , and the correction voltage output means 4 is selected.
2 is _equal to the reference stable voltage V _B
When the pressure decreases to a predetermined level or less, it is determined that the combustion oxygen has become insufficient, and an oxygen deficiency monitoring process of forcibly stopping the combustion of the burner 4 is performed.

[0031] in this way, when assuming the room temperature is the reference temperature T _B, based on the correction voltage V _TC22 is the output voltage of the thermocouple 20, by determining the lack of combustion oxygen, at room temperature Even if the ambient temperature of the thermocouple 20 (particularly the temperature near the cold junction where the thermocouple 20 is connected to the control unit 7) fluctuates due to the fluctuation, the oxygen deficiency monitoring means 44 accurately detects the lack of oxygen for combustion. Thus, it is possible to prevent erroneous detection of insufficient oxygen for combustion.

The combustion control means 45 includes the room temperature thermistor 13
The amount of combustion of the gas burner 4 is set to one of the strong combustion, the medium combustion, and the weak combustion so that the actual room temperature T _R detected by the above-described method matches the temperature control target temperature T _A set and supported by the room temperature setting switch 28. Switching to the stage, the temperature control for adjusting the heat radiation amount of the gas fan heater is performed.

The fan control unit 41 includes the combustion control unit 4
A target rotation speed (three stages corresponding to the above-described strong combustion, medium combustion, and weak combustion) is determined in accordance with the combustion amount designated from 0, and the rotation speed of the fan motor 14 detected by the rotation speed sensor 16 is set to the target rotation speed. The amount of energization to the fan motor 14 is controlled so as to match the rotation speed.

Next, the control operation of the heating operation by the combustion control unit 40 of the control unit 7 shown in FIG.
This will be described with reference to FIG. 2 and according to the flowcharts of FIGS.

In the gas fan heater according to the present embodiment, when power is supplied, the control unit 7 starts operating and enters a heating operation standby state. When the user turns on the operation switch 27, the control of the heating operation by the combustion control unit 40 is started according to the flowchart shown in FIG. The combustion control unit 40 first performs an ignition process of the gas burner 4 in STEP1. That is, the combustion control unit 40
First, the supply of combustion oxygen to the gas burner 4 is started by operating the blower fan 3 via the fan control unit 41, and electricity is supplied to the ignition electrode 19 to generate a spark discharge.
Then, the solenoid valves 24 and 25 are energized to open them, and the supply of fuel gas to the gas burner 4 is started to ignite the gas burner 4.

[0036] In subsequent STEP2, combustion control unit 40 starts the timer T _1, the timer T ₁ is until the time is up in STEP3 (e.g. 2 minutes), the gas burner 4
In order to stabilize the combustion state, the gas burner 4 is forcibly burned by the strong combustion. During the forced combustion of the gas burner 4, the combustion state of the gas burner 4 is unstable, so that the oxygen deficiency monitoring processing by the oxygen deficiency monitoring means 44 is not performed.

When the timer T ₁ has expired in STEP 3, the combustion control unit 40 terminates the forced combustion of the gas burner 4 and starts the operation of the combustion control unit 45. The combustion control means 45 increases the combustion amount of the gas burner 4 so that the actual room temperature T _R detected by the room temperature thermistor 13 coincides with the temperature control target temperature T _A set and instructed by the room temperature setting switch 28. The heat radiation amount of the gas fan heater is adjusted by switching to three stages of combustion, medium combustion, and weak combustion.

The combustion control unit 40, the amount of combustion gas burner 4 by the combustion control means 45, when changed in the middle combustion or the weak combustion from the intense combustion proceeds from STEP4 in STEP5, a timer is started T _2. Timer T ₂ are provided for waiting that the combustion state of the gas burner 4 is stabilized, when the timer T ₂ has timed in STEP6, combustion control unit 40 judges that the combustion state of the gas burner 4 is stabilized Proceeding to STEP 7, an oxygen deficiency detection process is performed.
It should be noted that, from the timer T ₂ is started in STEP5, S
Until the timer T ₂ times out up TEP5 (e.g. 1 minute), since the combustion state of the gas burner 4 is unstable, hypoxia detection processing of STEP7 is not performed.

The details of the oxygen deficiency detection process will be described later. If it is determined that the combustion oxygen is insufficient in the oxygen deficiency detection process, an oxygen deficiency flag is set. Therefore, ST
If the oxygen deficiency flag was set in EP8, the STE
Branching to P20, the oxygen deficiency monitoring means 44
5, the combustion of the gas burner 4 is stopped, and STEP 2
In step 1, the lamp 32 incorporated in the operation switch 27 is turned on and off, and the buzzer 31 is sounded to notify the user that combustion oxygen has become insufficient. This prevents the combustion of the gas burner 4 from continuing in a state where the combustion oxygen is insufficient.

After that, if the combustion amount of the gas burner 4 is constant, STEP4, STEP6, STEP7,
STEP8 and STEP9 are repeatedly executed. on the other hand,
When the combustion amount of the gas burner 4 is changed by the combustion control means 45, the process proceeds from STEP4 to STEP5,
Timer T ₂ is restarted. The timer T ₂ is when the time is up, the process proceeds to STEP7 from STEP6, the oxygen deficiency detection processing corresponding to the changed combustion amount is performed.

When the operation switch 27 is turned off by the user in STEP 9, the process proceeds to STEP 10, and the combustion control unit 40 closes the solenoid valves 24 and 25 to stop the combustion of the gas burner 4.

Next, the oxygen deficiency detection processing shown in STEP 7 of FIG. 3 will be described with reference to the flowcharts shown in FIGS. The oxygen deficiency detection process is executed by the correction voltage output unit 42, the stable voltage holding unit 43, and the oxygen deficiency monitoring unit 44 shown in FIG. STEP 30 is a process by the oxygen deficiency monitoring means 44, and is an initial setting process for resetting the oxygen deficiency flag which is set when the combustion oxygen becomes insufficient.

In the following STEP31 to STEP33, the correction
This is processing by the voltage output unit 42. Correction voltage output means
42 is the output voltage V of the thermocouple 20 in STEP 31_TCTake
In step 32, the room temperature thermistor 13 sets the actual
Room temperature T_RTo get. Then, the correction voltage output means 42
Is the correction voltage V obtained by the equation (1) described above in STEP33.
_TC22And the stable voltage holding means 43 and the oxygen deficiency monitoring means 4
4 is output.

Here, the reference temperature T in the equation (1)
_B (22 ° C.) is the room temperature setting switch 28 as described above.
Is a temperature that is assumed to be set with high frequency. The shortage of the oxygen for combustion occurs when the combustion of the gas burner 4 is continued for a long time. In this case, the combustion control means 45 controls the room temperature by the temperature control set by the room temperature setting switch 28. It is assumed that the target temperature T _A is maintained. Therefore, by this way the reference temperature T temperature control target _{temperature B} the setting frequency is assumed to be high, indeed the basis of the room temperature is likely to occur a lack of combustion oxygen, the output of the thermocouple 20 The voltage _VTC can be corrected. This makes it possible to detect the shortage of combustion oxygen with higher accuracy.

The following STEP34 to STEP36, STE
STEP40 to STEP42 branched from P34 and STEP50 to STE in FIG. 5 branched from STEP36.
P55 is processing by the stable voltage holding unit 43.

If the gas burner 4 is in a strong combustion state in STEP 34, the stable voltage holding means 43
The process proceeds, the intense combustion stability voltage V _S which is held in the memory 46 as a reference stable voltage V _B. Further, when the gas burner 4 was middle combustion state, the flow advances to STEP41 branches from STEP34 to STEP 40, a reference stable voltage V _B combustion stability voltage V _M among those stored in the memory 46. When the gas burner 4 is in a weak combustion state, the STE
The process proceeds from P34 to STEP 42 via STEP 40, and the weak combustion stable voltage V _W held in the memory 46 is set as the reference stable voltage V _B. This STEP34 to STEP3
5, and the processing of STEP40～STEP42, reference stable voltage V _B is set in accordance with the combustion state of the gas burner 4.

The correction voltage V calculated in the subsequent STEP 33
_{When TC22} exceeds a reference stable voltage V _B, STE in FIG
Branch to P50. STEP50~STEP55 is updating processing of the reference stable voltage V _B. That is, a stable voltage holding means 43, the V _TC22 as a new reference stable voltage V _B.

[0048] By this process, after starting the combustion of the gas burner 4, the maximum value of the correction voltage V _TC22 output from the correction voltage output unit 42 is a reference stable voltage V _B. Thus, when the output voltage of the thermocouple 20 is maximum, i.e. high concentration of the combustion oxygen, it is possible to set the correction voltage V _TC at most combustion conditions in good condition as a reference stable voltage V _B.

[0049] STEP51~STEP55 is a write operation to the memory 46 of the updated reference stable voltage V _B,
If the gas burner 4 was in a strong combustion state,
It is written in the memory 46 a reference stable voltage V _B as a strong combustion reference voltage V _S advances from 1 to STEP 52. Further, when the gas burner 4 which was a medium combustion state, the process proceeds to STEP54 branches from STEP51 to STEP 53, a stable voltage holding means 43, written in the memory 46 a reference stable voltage V _B as the middle combustion reference voltage V _M. Gas burner 4
Is in a weak combustion state, the STEP 51
Proceeds to STEP55 through the P53, stable voltage holding means 43, written in the memory 46 a reference stable voltage V _B as the weak combustion reference voltage V _W. Then, STEP 37 in FIG.
Proceed to.

Steps 37 and 38 in FIG. 4 are processing by the oxygen deficiency monitoring means 44.
When the correction voltage V _TC22 calculated in _{STEP 33} becomes equal to or lower than a voltage lower than the reference stable voltage V _B by a predetermined level α (corresponding to the reference voltage of the present invention), it is determined that the combustion oxygen has become insufficient. Then, the flow advances to STEP 38 to set an oxygen deficiency flag. On the other hand, when the correction voltage V _TC22 exceeds a voltage lower than the reference stable voltage V _B by a predetermined level α, the process branches from STEP 37 to STEP 38, so that the state of the oxygen deficiency flag is reset in STEP 30.

When the oxygen deficiency flag is set in the oxygen deficiency detection processing as described above, the process branches from STEP 8 to STEP 20 in FIG. 3 to stop the combustion of the gas burner 4 by the oxygen deficiency monitoring means 44 as described above. , The user is notified. In addition, STEP30, STEP37, STE
The processes in P38, STEP8, and STEP20 correspond to the oxygen deficiency monitoring process of the present invention.

[0052] Since in this embodiment exhibited a gas fan heater as an example of a combustion apparatus, the reference temperature T _B by setting the frequently 22 ° C., which is set at room temperature setting switch 28, more precisely Although the shortage of the oxygen for combustion is detected, the temperature of 22 ° C. is not absolute, and it is desirable to set an optimum reference temperature in consideration of the usage state of the combustion device.

In this embodiment, a gas fan heater is shown as an example of a combustion device, but another type of combustion device may be used. Further, the burner may be a combustion device using, for example, an oil burner other than the gas burner.

Further, in this embodiment, the combustion device in which the combustion amount of the gas burner is switched among three stages of strong combustion, medium combustion, and weak combustion is shown, but it is switched to more stages such as seven stages and thirteen stages. It may be something.

In the present embodiment, the room temperature thermistor 13 (corresponding to the room temperature detecting means of the present invention) is used as the ambient temperature detecting means of the present invention to detect the ambient temperature of the thermocouple 20. The present invention can be applied to a combustion device having no room temperature thermistor 13 by providing a temperature detection unit for detecting the ambient temperature of the thermocouple 20.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a hot air heater that is a combustion device of the present invention.

FIG. 2 is a control block diagram of the hot air heater shown in FIG.

FIG. 3 is an operation flowchart of a combustion control unit shown in FIG. 2;

FIG. 4 is an operation flowchart of a combustion control unit shown in FIG. 2;

FIG. 5 is an operation flowchart of a combustion control unit shown in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Body case, 2 ... Duct, 3 ... Blower fan, 4 ... Burner, 5 ... Air supply duct, 6 ... Gas supply pipe, 7 ... Control unit, 8 ... Inlet, 9 ... Air outlet, 10 ... Air filter,
11: movable looper, 12: geared motor, 13: room temperature thermistor, 14: fan motor, 15: rotating blade, 1
6: rotation speed sensor, 17: combustion cylinder, 19: ignition electrode, 2
0: thermocouple, 21: intake port, 22: nozzle, 24, 25
... solenoid valve, 26 ... solenoid proportional valve, 27 ... operation switch, 2
8: Room temperature setting switch, 29: Ventilation lamp, 30: Filter lamp, 31: Buzzer, 32: Lamp with built-in operation switch, 33: Overheat prevention thermistor, 40: Combustion control unit, 41: Fan control unit, 42: Correction voltage Output means, 4
3: stable voltage holding means, 44: oxygen deficiency monitoring means, 45: combustion control means

Continued on the front page (72) Inventor Haruki Uno 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi, Aichi F-term in Rinnai Corporation (reference) 3K003 TA01 TB04 TB06 TC05 TC07 3K005 TA01 TB07 TC04 VA04

Claims (2)

[Claims] 1. A burner, a thermocouple for outputting a voltage corresponding to a combustion state of the burner, an ambient temperature detecting means for detecting an ambient temperature of the thermocouple, and a temperature detected by the ambient temperature detecting means. Correction voltage output means for outputting a voltage obtained by correcting the output voltage of the thermocouple according to a difference from a reference temperature, and the correction voltage output means when the combustion state of the burner is stabilized after the start of combustion of the burner A stable voltage holding means for holding the output voltage of the burner, and after the combustion state of the burner is stabilized, the output voltage of the correction voltage output means is equal to or less than a reference voltage determined based on the voltage held by the stable voltage holding means. A combustion deficiency monitoring means for performing an oxygen deficiency monitoring process for judging that the combustion oxygen has become inadequate and stopping the combustion of the burner. 2. The heating device according to claim 1, wherein the combustion device has a room temperature detecting means for detecting a room temperature, wherein the room temperature detecting means is used as the ambient temperature detecting means.
A combustion device as described.