JP2908247B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device such as a water heater.

[0002]

2. Description of the Related Art In a water heater, for example, a burner amount required to match a tapping temperature detected by a tapping temperature sensor with a set temperature set by a user is determined.
The number of rotations of the combustion fan is controlled to a set number of rotations determined according to the required combustion amount, and the proportional valve provided in the fuel supply path to the burner according to the required combustion amount or the actual rotation number of the combustion fan. What controls an opening degree is generally known.

[0003] This type of combustion apparatus is designed to reduce the number of revolutions of the combustion fan on the assumption that the number of revolutions of the combustion fan and the amount of air blown from the combustion fan to the burner (air supply) always correspond to each other in a fixed relationship. Although the control is performed at the set rotation speed, in practice, the load of the combustion fan changes due to clogging of the exhaust port, and in such a case, even if the rotation speed of the combustion fan is the same, the combustion fan The actual amount of air blown from the air to the burner (air supply amount) changes. Therefore, even if the number of rotations of the combustion fan is controlled to the set number of rotations determined according to the required combustion amount, the actual amount of air blown to the burner is not always maintained at an appropriate amount.

[0004] Therefore, in this type of combustion device,
The air flow rate sensor (wind speed sensor) disposed in the air flow path from the combustion fan to the burner detects the actual air flow rate to the burner from time to time, and sets the air flow rate corresponding to the required combustion rate of the burner. There is also known a method in which the number of revolutions of a combustion fan is controlled from time to time so that the actual air volume matches the air volume (for example, Japanese Utility Model Laid-Open No. 1-129561,
See JP-A-60-143251. In this type of combustion device, even when the target air volume cannot be obtained at a predetermined rotation speed due to clogging of a foreign substance in an exhaust port or the like, it is dealt with by correcting the rotation speed of the combustion fan.

However, when the load on the combustion fan becomes extremely large due to the clogging of the exhaust port, the air pressure in the combustion chamber containing the burner increases, and the ejection speed of the fuel ejected from the nozzles increases. May become incomplete combustion because of slowing down. Furthermore, even if the combustion fan is rotated at the maximum number of revolutions, air required for combustion of the burner may not be obtained in some cases, which may also result in incomplete combustion.

[0006]

SUMMARY OF THE INVENTION The present invention aims at improving such a combustion apparatus, and more specifically, can prevent incomplete combustion when the exhaust port is clogged. It is another object of the present invention to provide a combustion device that can determine the degree of clogging of an exhaust port at an early stage and can avoid a situation in which an inappropriate combustion operation is performed at an early stage.

[0007]

In order to achieve the above object, a first aspect of the present invention is to provide a combustion chamber containing a burner, an exhaust port communicating with the combustion chamber, and a combustion air supplied to the burner. Fan, an air volume sensor for detecting the air volume from the combustion fan to the burner, and a set air volume for obtaining the required combustion volume of the burner by detecting the air volume detected by the air volume sensor during the combustion operation of the burner. A fan control means for controlling the number of revolutions of the combustion fan so as to match the reference value. When the combustion fan is rotated to a predetermined number of revolutions, a reference air volume obtained in a normal state is stored in advance. Reading means for reading, from the storage means, a reference air flow rate corresponding to a predetermined rotation speed of the combustion fan; and the air flow sensor corresponding to a predetermined rotation speed of the combustion fan. When the detected air volume is lower than the reference air volume, a difference between the detected air volume and the reference air volume is obtained, and when the value of the difference exceeds a predetermined value, operation stopping means for stopping the combustion operation of the burner. It is characterized by having.

According to a second aspect of the present invention, there is provided a combustion chamber accommodating a burner, an exhaust port communicating with the combustion chamber, a combustion fan for blowing combustion air to the burner, and a combustion fan from the combustion fan to the burner. An air flow sensor for detecting an air flow, and the combustion fan
A rotation speed sensor that detects the rotation speed of the burner, and a rotation speed of the combustion fan that matches a detection airflow detected by the airflow sensor during the combustion operation of the burner with a set airflow for obtaining a required combustion amount of the burner. in a combustion apparatus provided with a control for the fan control unit, a storage unit data indicating a relationship between the engine speed and the reference air amount obtained in the normal by the rotational speed of the combustion fan it has been stored in advance, before
Reading means for reading out from the storage means a reference air flow rate corresponding to the rotation speed of the combustion fan obtained by the rotation speed sensor; and detection obtained by the air flow rate sensor corresponding to the rotation speed of the combustion fan obtained by the rotation speed sensor. Air volume
If less than the reference air amount corresponding to the rotational speed, it obtains the ratio of the reference air amount and said analyzing <br/> Defuryou, when the value of the ratio exceeds a predetermined value, the combustion operation of the burner Operation stopping means for stopping the operation.

In a third aspect of the present invention, when the combustion fan is rotated at a predetermined rotation speed, a reference air volume obtained in a normal state is stored in advance, Reading means for reading out the corresponding reference air flow from the storage means, and the fan control means rotating the combustion fan at the predetermined rotation speed, and when the reference air flow is given to the fan control means as the set air flow, the detected air flow becomes When the number of rotations when the reference air volume is matched exceeds the predetermined number of rotations, the amount of change in the number of rotations is determined from the difference between the two numbers of rotations,
Operation stop means for stopping the combustion operation of the burner when the change amount exceeds a predetermined amount.

According to a fourth aspect of the present invention, there is provided a combustion chamber containing a burner, an exhaust port communicating with the combustion chamber, a combustion fan for blowing combustion air to the burner, and a burner from the combustion fan. An air flow sensor for detecting an air flow to the burner, a rotation speed sensor for detecting a rotation speed of the combustion fan, and a detection air flow detected by the air flow sensor during a combustion operation of the burner to obtain a required combustion amount of the burner. In a combustion device having fan control means for controlling the number of revolutions of the combustion fan to match the set air volume, data indicating a relationship between the number of revolutions of the combustion fan and a reference air volume obtained in a normal state by the number of revolutions is obtained. reading means for reading a pre-stored memory means, the reference air quantity corresponding to the rotational speed of the combustion fan obtained by the rotational speed sensor from the storage unit, the file Give the detection air amount coincides with the reference air volume giving the reference air volume as the set air volume to the control means
When the number of rotations of the combustion fan exceeds the number of rotations corresponding to the reference airflow, the amount of change in the number of rotations is obtained from the ratio of the two numbers of rotations, and the amount of change exceeds a predetermined amount. when, characterized in that a driving stopping means for stopping the combustion operation of the burner.

According to a fifth aspect of the present invention, there is provided a storage means in which data indicating the relationship between the number of revolutions of the combustion fan and a reference air volume obtained under normal conditions based on the number of revolutions is stored in advance, Reading means for reading a reference air flow rate corresponding to a rotation speed from the storage means, and when a detection air flow rate obtained by the air flow rate sensor corresponding to the rotation speed of the combustion fan falls below a predetermined air flow rate smaller than the reference air flow rate, Operation stop means for stopping the combustion operation of the burner.

[0012] The operation stopping means in any one of the first to fifth aspects is provided at an initial stage of the combustion operation, particularly,
It is characterized in that it operates during prepurge or when the burner is ignited.

[0013]

According to the first aspect of the present invention, when the exhaust port is clogged and has progressed to some extent, the detected air volume obtained by the air volume sensor at a predetermined rotation speed of the combustion fan is normal. At times, the air flow rate is relatively larger than the reference air volume obtained at the predetermined rotation speed. Therefore, when a difference between the detected air volume and the reference air volume at the predetermined rotation speed is obtained, and the value of the difference exceeds a predetermined value,
It can be determined that the clogging of the exhaust port has progressed to some extent. In such a case, by stopping the combustion operation by the operation stop means, a situation in which inappropriate combustion operation is performed is avoided. Here, in this aspect, since the combustion fan is rotated at a predetermined rotation speed, only the predetermined value corresponding to the predetermined rotation speed may be used. In other words, the predetermined value for determining that the clogging of the exhaust port has progressed to a certain extent is a value of the difference between the air volumes predicted and obtained, and therefore differs depending on the rotation speed. Specifically, if the number of rotations is large, a large amount of air can be obtained, so the predetermined value is large, and if the number of rotations is small, the amount of air that can be obtained is small.
The predetermined value becomes small. Then, when the combustion fan rotates at a certain rotational speed which is not a predetermined value, in order to make the above determination, a predetermined value corresponding to the rotational speed at that time must be used. For this reason, since it is necessary to store a predetermined value corresponding to all the rotation speeds, the data becomes complicated, and in some cases, a huge amount of data must be prepared.
Therefore, in the first aspect of the present invention, by rotating the combustion fan to a predetermined rotation speed, only a single predetermined value corresponding to a predetermined rotation speed is used, and a difference between an actual air volume and the predetermined value is used. Makes it easy to make comparison decisions. In addition, by using the predetermined rotation speed, the storage means may store the reference airflow corresponding to the predetermined rotation speed.

In a second aspect of the present invention, a ratio between the detected air volume and the reference air volume is determined, and when the value of the ratio exceeds a predetermined value, the combustion stop operation of the burner is performed by the operation stop means. To stop. That is, as the clogging of the exhaust port occurs and the clogging progresses, the value of the ratio obtained at this time increases, and when the value of the ratio exceeds a predetermined value, the clogging of the exhaust port progresses greatly. Can be determined to be. In this aspect, the ratio between the detected air volume and the reference air volume obtained when the exhaust port is clogged is constant regardless of the rotation speed of the combustion fan. Therefore, it is possible to easily compare and determine the value of the ratio with a single predetermined value without rotating the combustion fan at a predetermined rotation speed. Since the storage means of this aspect stores data indicating the relationship between the number of rotations of the combustion fan and the reference airflow obtained under normal conditions based on the number of rotations, the reference airflows corresponding to all the rotation speeds are stored. The data can be read by the reading means.

Further, in the third aspect of the present invention, when the exhaust port is clogged and has progressed to some extent, as described above, the air flow rate sensor is rotated at a predetermined rotational speed of the combustion fan. The detected air volume obtained by
In a normal state, the airflow rate is relatively larger than the reference air volume obtained at the predetermined rotation speed. Thus, the number of revolutions when the combustion fan is controlled to obtain the reference air volume is higher than the predetermined number of revolutions. Therefore, a change amount is obtained from a difference between the predetermined rotation speed and the rotation speed of the combustion fan when the reference air volume is obtained. If the change amount exceeds the predetermined amount, the clogging of the exhaust port progresses to some extent. It can be determined that it is in a state of being performed. In such a case, by stopping the combustion operation by the operation stop means, a situation in which inappropriate combustion operation is performed is avoided. It should be noted that rotating the combustion fan to the predetermined number of revolutions here is the same as in the first embodiment described above.

According to a fourth aspect of the present invention, the amount of change is determined from the ratio of the number of revolutions when the detected air volume is detected to the number of revolutions of the combustion fan when the reference air volume is obtained. When the pressure exceeds a predetermined amount, the burner combustion operation is stopped by the operation stop means. The greater the degree of clogging of the exhaust port, the greater the amount of change determined from the ratio of both rotation speeds, and if the amount of change exceeds a predetermined amount,
It can be determined that the clogging of the exhaust port has greatly progressed. In this aspect, no matter what number of revolutions the combustion fan rotates, the ratio between the two revolutions obtained when the exhaust port is clogged is constant. Similarly, the amount of change can be easily compared and determined by a single predetermined amount without rotating the combustion fan at a predetermined rotation speed.

Further, in the fifth aspect of the present invention, when the exhaust port is clogged, the detected air volume obtained by the air volume sensor corresponding to the rotation speed of the combustion fan is set to a normal value. It becomes smaller than the reference air volume obtained at the rotation speed. Then, if the detected air volume at the rotation speed is lower than a predetermined air volume smaller than the reference air volume,
Judgment is made that clogging of the exhaust port is progressing, and combustion is stopped.

Further, the operation stop means operates at an early stage of the start of the operation of the combustion device, whereby it is possible to grasp a state in which the exhaust port is clogging at an early stage.

If the combustion fan operates at the time of pre-purge or at the time of ignition of the burner, the rotation speed of the combustion fan is constant at the time of pre-purge or at the time of ignition of the burner. It is easier to determine the progress of the clogging of the exhaust port than during the changing combustion operation.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment corresponding to the first aspect of the present invention will be described with reference to FIGS. FIG. 1 is a system configuration diagram of the combustion device of the present embodiment, FIG. 2 is a block configuration diagram of a main part of the combustion device of FIG. 1, and FIG. 3 is a diagram showing a relationship between a rotation speed and an air volume.

The combustion device of the present embodiment is a water heater, and FIG.
1 is a heat exchanger 2 and a burner 3 for heating the heat exchanger 2
, 4 is a water pipe installed through the heat exchanger 2, 5 is a flow sensor for detecting the flow rate of water flowing through the water pipe 4 on the upstream side of the heat exchanger 2, 6 is heat exchange A temperature sensor for detecting a tapping temperature of water flowing through the water pipe 4 downstream of the vessel 2, a gas supply pipe 7 for supplying gas to the burner 3,
Reference numeral 9 denotes an opening / closing solenoid valve and a gas proportional valve which are sequentially interposed in the gas supply pipe 7 from the upstream side, 10 denotes a combustion fan for blowing combustion air to the burner 3, 11 denotes a fan motor for driving the combustion fan 10, 12 Is a rotation speed sensor configured by a Hall element or the like for detecting the rotation speed of the combustion fan 10,
Reference numeral 13 denotes an air flow sensor such as a hot-wire type air flow sensor disposed in a ventilation passage 14 from the combustion fan 10 to the burner 3, reference numeral 15 denotes an operation unit for a user to set a tapping temperature, and reference numeral 16 denotes an operation unit 15. The fan motor 1 is set in accordance with the set temperature of the hot water and the detection signals of the sensors 5, 6, 12, and 13.
1 is a controller for controlling the gas proportional valve 9, etc., 17 is an igniter for igniting the burner 3, and 18 is a burner 3
5 is a frame rod for detecting a combustion state such as the presence or absence of a misfire.

The burner 3 and the heat exchanger 2 are accommodated in a combustion chamber 19 in the water heater main body 1.
An exhaust port 20 is provided in communication with the upper part. The upstream side of the water pipe 4 is connected to a water pipe (not shown), and the downstream side is connected to a hot water tap (not shown) in a kitchen or a bathroom.

The controller 16 is constituted by an electronic circuit including a microcomputer and the like.
As shown in FIG. 2, the functional configuration of the controller 16 includes a set temperature provided from the operation unit 15, an incoming water temperature detected by an incoming water temperature sensor (not shown), and a hot water supply detected by the temperature sensor 6. A required combustion amount calculation unit 21 is provided for calculating a required combustion amount of the burner 3 required to make the tap water temperature coincide with the set temperature based on the temperature and the flow rate detected by the flow sensor 5. An air volume setting unit 22 is provided for setting a target air volume (a supply amount of combustion air) from the combustion fan 10 to the burner 3 according to a required combustion volume. In addition, the combustion fan 1 is set in accordance with the target air volume (set air volume) set by the air volume setting unit 22 and the actual air volume of the combustion fan 10 detected by the air volume sensor 13.
A fan control unit 23 that controls the number of rotations of 0 via the fan motor 11 is provided. The fan control unit 23 includes a reference rotation speed setting unit 24 for setting a reference rotation speed (for example, a rotation speed of 50% of the maximum rotation speed), and a setting rotation speed set by the air volume setting unit 22 for the combustion fan 10. And a correction unit 25 that corrects the rotation speed of the combustion fan 10 in accordance with the air volume detected by the air volume sensor 13 when the target air volume cannot be obtained even if the rotation is performed. Further, the controller 16 stores reference data indicating the relationship between the air flow rate and the rotation speed of the combustion fan 10 in a normal state (when the exhaust port 20 is not closed).
(Storage means) and a reading section 2 for reading a reference air volume corresponding to the reference rotation speed from the storage section 26 based on the reference data.
7 (reading means) and the combustion fan 10
A difference between the detected airflow obtained by the airflow sensor 13 and the reference airflow when the is rotated at the reference rotation speed, and a value obtained by the airflow difference calculation unit 28 is a predetermined value. Determining unit 2 for determining whether or not exceeds
9, a valve control unit 30 that controls the degree of gas supply to the burner 3 by controlling the degree of opening of the gas proportional valve 9 in accordance with the number of revolutions of the combustion fan 10 detected by the revolution number sensor 12, and the like.
The fan control unit 2 according to the determination result of the determination unit 29
A stop command unit 31 for stopping the combustion fan 10 via the solenoid valve 3 and cutting off the gas supply to the burner 3 via the solenoid valve 8 is provided. The reference data stored in the storage unit 26 is data indicated by a solid line a in FIG. In the present embodiment, the combustion stopping means of the first aspect of the present invention comprises the air flow difference calculating section 28, the determining section 29, and the stop command section 31.

When the flow of water through the water pipe 4 is started, the controller 16 detects this through the flow rate sensor 5, and
In response to the detection, the combustion controller 10 is driven to rotate by the fan control unit 23 via the fan motor 11, and the solenoid valve 8 of the gas supply pipe 7 is opened to start gas supply to the burner 3. Burner 3 via igniter 17
And the hot water supply operation is started. At this time, prior to the ignition of the burner 3, the fan control unit 23 rotates the combustion fan 10 for a certain period of time at the reference rotational speed to perform a prepurge.
Slow ignition is performed.

When it is detected via the flow rate sensor 5 that the flow of the water through the water pipe 4 has been completed, the controller 16 closes the solenoid valve 8 to shut off the gas supply to the burner 3 and to control the fan control unit. 23 stops the combustion fan 10, thereby ending the hot water supply operation. Incidentally, such an end operation of the hot water supply operation is similarly performed when the burnout of the burner 3 is detected by the frame rod 18 during the hot water supply operation.

Next, the operation of the water heater of this embodiment will be described.

As described above, at the start of the hot water supply operation, the controller 16 causes the fan control unit 23 to rotate the combustion fan 10 at the reference rotation speed at a constant speed. Turn on the ignition. At this time, the reading unit 27 in accordance with the reference data indicated by the solid line a in FIG. 3 of the storage unit 26, giving the reference air amount Fa ₀ corresponding to the reference rotation speed Na ₀ in the air amount difference calculating unit 28,該風amount The difference calculator 28 calculates a difference between the reference air volume Fa ₀ and the air volume detected by the air volume sensor 13 at this time.

In this case, if the exhaust port 20 is clogged, for example, as shown in FIG.
b ₀ ″ (<Fa ₀ ), and the air volume difference calculated by the air volume difference calculation unit 28 is (Fa ₀ −Fb ₀ ). The air volume difference (Fa ₀ −Fb ₀ ) is determined by the determination unit 29. It is determined whether or not the difference exceeds a predetermined value, and if the air flow difference (Fa ₀ −Fb ₀ ) exceeds the predetermined value, the combustion operation is stopped by the stop command unit 31. Is the value of the air flow difference that does not cause a risk of incomplete combustion even if the exhaust port is clogged, that is, the air flow difference (Fa ₀ −F).
If b ₀ ) exceeds the predetermined value, it is possible to determine that the clogging of the exhaust port is progressing, and that if the combustion operation is performed, there is a risk of incomplete combustion or the like.

In this embodiment, the storage unit 26
The reference data indicated by the solid line a in FIG.
Since the rotation of the combustion fan 10 at the reference rotation speed is performed at the time of pre-purge, a specific reference rotation speed is basically determined in advance. Therefore, as another example, only the reference airflow corresponding to the specific reference rotation speed may be stored in the storage unit 26. Further, when the reference rotation speed is appropriately determined,
The predetermined value corresponding to each reference rotation speed at that time must be prepared, but in the present embodiment, since the specific reference rotation speed is predetermined, the predetermined value is set to the specific reference rotation speed. In this case, it is sufficient to prepare a device corresponding to the above, and the data amount is prevented from increasing.

In the judgment by the judging section 29, if the air flow difference (Fa ₀ -Fb ₀ ) is smaller than a predetermined value or if the air flow difference (Fa ₀ -Fb ₀ ) is equal to the predetermined value, the prepurge and Subsequent to mild ignition of the burner 3, ignition of the burner 3 is performed.

At this time, first, the required combustion amount calculation unit 21 determines the required combustion amount of the burner 3 required to make the tapping temperature detected by the temperature sensor 6 coincide with the set temperature set by the operation unit 15. Inlet water temperature, hot water temperature,
It is determined every moment based on the flow rate detection data and the like. Further, the air volume setting unit 22 of the controller 16 includes a required combustion amount calculation unit 2.
The target air volume from the combustion fan 10 to the burner 3 for obtaining the required combustion volume determined in 1 is set according to a predetermined data table or the like.

Next, the controller 16 controls the combustion fan 10 by the fan control unit 23. That is,
The fan control unit 23 controls the combustion fan 1 corresponding to the target air volume.
0 is set in accordance with a predetermined data table or the like, and the fan motor 11
Drive the combustion fan 10 via the.

At this time, the correction unit 25 of the fan control unit 23
When the air volume detected by the air volume sensor 13 is smaller than a target air volume within a predetermined range, the actual air volume is increased by increasing the rotation speed of the combustion fan 10 from the initial rotation speed (set rotation speed). Let it. Thereby, the rotation speed of the combustion fan 10 is corrected so that the target air volume and the actual air volume match.

As described above, the controller 16 not only corrects the rotation speed of the combustion fan 10 when the target air volume cannot be obtained, but also when the clogging of the exhaust port 20 is progressing (the detected air volume and the target air volume). (When the difference is larger than a predetermined value), the combustion operation is avoided in advance to prevent incomplete combustion and the like.

On the other hand, the valve controller 30 of the controller 16
Controls the degree of gas supply to the burner 3 by controlling the opening of the gas proportional valve 9 in parallel with the control of the combustion fan 10 as described above. In this case, basically, the valve control unit 3
0 is the combustion fan 1 detected by the rotation speed sensor 12
The opening of the gas proportional valve 9 is controlled in accordance with the actual rotation speed of zero. Therefore, when there is no clogging of the exhaust port, the rotation speed of the combustion fan 10 and the actual air volume correspond to each other. 9 by controlling the opening degree of the burner 3
The amount of gas supplied to the burner 3 is controlled to the target air volume.
The burner 3 burns at the required combustion amount.

When the load of the combustion fan 10 fluctuates, the rotation speed of the combustion fan 10 is corrected so that the actual air volume matches the target air volume as described above. Even if the air volume to the air is the same, the rotation speed of the combustion fan 10 increases and decreases. Therefore, simply controlling the opening degree of the gas proportional valve 9 in accordance with the rotation speed of the combustion fan 10 does not affect the combustion fan 1 even if the air volume to the burner 3 is the same.
The degree of opening of the gas proportional valve 9 changes following the rotation speed of 0, and the amount of gas supplied to the burner 3 changes. Therefore, the valve control unit 30 of the controller 16 adjusts the opening degree of the gas proportional valve 9 according to the airflow detected by the airflow sensor 13 to the required combustion amount of the burner 3 in order to cancel the correction amount of the rotation speed of the combustion fan 10. Let it.

By the way, in the above embodiment, the calculation of the difference between the detected air volume and the reference air volume has been described.
In the case of the second aspect , a ratio between the detected air volume and the reference air volume is calculated instead of the difference. That is, although not shown, in an embodiment corresponding to the second aspect of the present invention, an air volume ratio calculation unit is provided in place of the air volume difference calculation unit 28 in FIG. 2, and the ratio calculated by the air volume ratio calculation unit is provided. The determination unit 29 determines whether the ratio exceeds a predetermined value. If the ratio exceeds the predetermined value, the stop operation unit 31 stops the combustion operation .

Next, a second embodiment corresponding to the third aspect of the present invention will be described.
Will be described with reference to FIG. FIG. 4 is a block diagram of a main part of the apparatus of the present embodiment. The combustion device of the present embodiment is provided in the water heater of FIG.
The system configuration of the water heater is the same as that of FIG.
Hereinafter, in the description, the same components as those of the water heater of FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the water heater provided with the combustion device of the present embodiment, the controller 16 comprises a necessary combustion amount calculating unit 21, an air volume setting unit 22, a fan control unit 23, and a storage unit, as in the first embodiment. 26, a reading unit 27, a determination unit 29, a valve control unit 30, and a stop command unit 31. The fan control unit 23 includes a reference rotation speed setting unit 24 and a correction unit 25, as in the first embodiment.

The controller 16 of this embodiment is newly provided with a rotation speed change amount calculation unit 32 for calculating a difference between the reference rotation speed and the corrected rotation speed to obtain a change amount of the rotation speed. ing. The rotation speed change amount calculation unit 32 includes a reference rotation speed acquisition unit 33 that obtains the reference rotation speed set by the reference rotation speed setting unit 24 during prepurge, and a rotation speed of the combustion fan 10 by the correction unit 25 during prepurge. Is corrected, the difference between the rotation speed obtained by the corrected rotation speed obtaining unit 34 and the rotation speed obtained by the corrected rotation speed obtaining unit 34, which obtains the corrected detected airflow, and the rotation speed obtained by the reference rotation speed setting unit 24. And a subtraction unit 35 for calculating Further, the fan control unit 23 of the controller 16 of the present embodiment is newly provided with a reference air volume acquisition unit 36 that controls the combustion fan 10 at the reference rotation speed and simultaneously acquires the reference air volume as the set air volume. . The operation stopping means according to the third aspect of the present invention includes the rotation speed change amount calculating section 32, the determining section 29, and the stop command section 31 in this embodiment.

In the water heater of the present embodiment, the operations of the required combustion amount calculating section 21, the air volume setting section 22, the valve control section 30, and the stop command section 31 are the same as those of the above-described embodiment.

The operation of the water heater of this embodiment, which is different from the water heater of the first embodiment, will now be described.

In the water heater of this embodiment, the fan control unit 23 of the controller 16 performs the prepurge and the mild ignition of the burner 3 at the beginning of the combustion operation, as in the first embodiment. At this time, first, the fan control unit 23
Rotates the combustion fan 10 at the reference rotation speed, and obtains the reference rotation speed acquisition unit 3 of the rotation speed change amount calculation unit 32.
3 is given a reference rotation speed. At the same time, the air volume sensor 13 detects the air volume blown from the combustion fan 10 rotated at the reference rotation speed. On the other hand, the reference air volume is read from the reference data stored in the storage unit 26 by the reading unit 27, and the fan control unit 23
6, the reference air volume is obtained as the set air volume. By doing so, the correction unit 25 provided in the fan control unit 23
Thus, the rotation speed of the combustion fan 10 is corrected so that the detected air volume matches the reference air volume. Then, when the detected airflow matches the reference airflow, the corrected rotation speed acquisition unit 34 of the rotation speed change amount calculation unit 32 obtains the corrected rotation speed of the combustion fan 10 from the rotation speed sensor 12. According to FIG. 3, when the detected air volume Fb ₀ coincides with the reference air volume Fa ₀ according to FIG. 3, the rotation speed N corresponding to the position (Fb ₀ = Fa ₀ ) in the figure.
b ₀ can be obtained by the rotation speed sensor 12.

Next, the amount of change in the number of revolutions is calculated from the difference between the reference number of revolutions and the corrected number of revolutions by the subtraction unit 35 of the number-of-rotational-number-variation calculating unit 32.

In this case, if the exhaust port 20 is clogged, the rotational speed Nb ₀ (> Na ₀ ) after correction with respect to the reference rotational speed Na ₀ is obtained as shown in FIG. 3, for example. The change amount of the rotation speed obtained by the subtraction unit 35 is (Nb ₀ −N
a ₀ ). Then, the amount of change (Nb ₀ -Na _0), the whether exceeds a predetermined value is determined by the determining unit 29, when the amount of change (Nb ₀ -Na ₀₎ had exceeded a predetermined value Then, the combustion operation is stopped by the stop command unit 31.
Here, the predetermined value is a value of the rotation difference to the extent that there is no fear of incomplete combustion or the like even if the exhaust port is clogged. Therefore, when the change amount (Nb ₀ −Na ₀ ) exceeds a predetermined value, the air required for combustion of the burner 3 cannot be sufficiently blown by the relatively large load applied to the combustion fan 10. Since the exhaust port is in the state, clogging of the exhaust port progresses, and it can be determined that there is a risk of incomplete combustion or the like if the combustion operation is performed.

If the change amount (Nb ₀ −Na ₀ ) is smaller than a predetermined value or the change amount (Nb ₀ −Na ₀ ) is 0 in the judgment by the judging section 29, the pre-purge and the burner Following the mild ignition of 3, the burner 3 is ignited,
Subsequent operations are the same as in the first embodiment.

As described above, also in this embodiment, similarly to the first embodiment described above, when the clogging of the exhaust port 20 is progressing, it is possible to avoid performing the combustion operation in advance. Thus, incomplete combustion and the like can be prevented.

In the above-described embodiment, the difference between the rotation speed of the combustion fan 10 when the detected air flow is obtained and the rotation speed of the combustion fan 10 when the reference air flow is obtained is described. According to a fourth aspect of the present invention, the difference
Instead, calculating the ratio of the two speed. That is, examples corresponding to the fourth aspect of the present invention, the speed change amount calculation unit 32 in FIG. 4, the change in rotational speed by calculating the ratio between the rotation speed after correction and the reference rotation speed The amount of change is determined, and it is determined whether or not the change amount exceeds a predetermined amount by the determination unit 29. If the ratio value exceeds the predetermined value, the stop command unit 31 Stop the combustion operation .

Next, a third embodiment corresponding to the fifth aspect of the present invention will be described.
Will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a block diagram of a main part of the apparatus according to the present embodiment, and FIG. 6 is a diagram showing the relationship between the number of rotations and the air volume. Note that the combustion apparatus of the present embodiment is provided in the water heater of FIG. 1, and the system configuration of the water heater is the same as that of FIG. Less than,
In the description, the same components as those of the water heater in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the water heater equipped with the combustion device of this embodiment, the controller 16 includes a necessary combustion amount calculating unit 21, an air volume setting unit 22, a fan control unit 23, and a storage unit, as in the first embodiment. 26, a reading unit 27, a determination unit 29, a valve control unit 30, and a stop command unit 31. Similar to the first and second embodiments, the fan control unit 23 includes a reference rotation speed setting unit 24 for rotating the combustion fan 10 at a predetermined rotation speed at the time of pre-purge and mild ignition of the burner 3.
And a correction unit 25 are provided.

The determination unit 29 is obtained by the air flow sensor 13 in accordance with the rotation speed of the combustion fan 10 detected by the rotation speed sensor 12 after the correction unit 25 corrects the rotation speed of the combustion fan 10. In addition to determining whether the detected air volume is larger than the reference air volume corresponding to the corrected rotation speed, if the detected air volume is smaller than the reference air volume, the detected air volume at that time is determined in advance according to a data table or the like. It is to determine whether the air flow is smaller than a predetermined air flow corresponding to the determined reference air flow. Here, according to the configuration of the fifth aspect of the present invention, the operation stopping means is constituted by the determination unit 29 and the stop command unit 31. The reference data stored in the storage unit 26 is data indicated by a solid line b in FIG.

Next, the operation of the water heater of this embodiment will be described.

In the water heater according to the present embodiment, the fan control unit 23 of the controller 16 operates similarly to the above-described embodiment.
Pre-purge and mild ignition of the burner 3 are performed at the beginning of the operation.
The fan control unit 23 includes the reference rotation speed setting unit 2
4, the combustion fan 10 is rotated at the reference rotation speed. At the same time, the air volume sensor 13 detects the air volume blown from the combustion fan 10 rotated at the reference rotation speed. On the other hand, a reference airflow corresponding to a reference rotation speed is read from the reference data stored in the storage unit 26 by the reading unit 27, and the detected airflow is reduced by the correction unit 25 provided in the fan control unit 23 to the reference rotation speed. The rotation speed of the combustion fan 10 is corrected so as to match the reference airflow corresponding to. Thereafter, when the detected airflow matches the reference airflow corresponding to the reference rotation speed, the reading unit 27 reads out the reference airflow corresponding to the corrected rotation speed from the storage unit 26.

At this time, the reading unit 27 detects the rotation speed of the combustion fan 10 by the correction unit 25 in accordance with the reference data indicated by the solid line b in FIG. given reference air amount Fa ₀ corresponding to the rotational speed N ₀ obtained on the determination unit 29, the determination unit 29 reference air amount Fa corresponding to the rotational speed of the corrected
A comparison is made between ₀ and the detected air volume (equal to the reference air volume corresponding to the reference rotation speed) obtained by the air volume sensor 13 at this time.

In this case, if the exhaust port 20 is clogged, for example, as shown in FIG.
b ₀ "a (<Fa _0). Then, the detection air amount Fb ₀ by judging unit 29 is judged whether below a predetermined airflow Fc _0, the detection air amount Fb ₀ below a predetermined airflow Fc ₀ (Fb ₀ <Fc ₀ ), the combustion operation is stopped by the stop command unit 31. Here, the predetermined air volume Fc ₀ is not affected by variations due to the accuracy of the air volume sensor 13 and slight influences due to outside air. However, the air volume is a predetermined air volume so that it is not erroneously determined that the clogging of the exhaust port 20 is progressing, that is, when the detected air volume Fb ₀ is lower than the predetermined air volume Fc _0. can be determined that the clogging of the exhaust port is in progress. the flow rate Fc _0, as shown in phantom c in FIG. 6, is determined is respectively different values by the reference air quantity corresponding to the rotational speed I have.

[0056] Further, in the determination by the determining unit 29, even below the reference air amount Fa ₀ detected airflow Fb ₀ corresponds to the rotational speed that is corrected after the rotation speed of the correction of the combustion fan 10, predetermined airflow Fc If it is larger than ₀ , the combustion operation is continued. As described above, in the present embodiment, when the combustion fan 10 is rotated at the reference rotation speed, the correction unit 25 corrects the rotation speed of the combustion fan 10 so that the detected airflow and the reference airflow coincide with each other. , The detected air volume after correction is
When the determination unit 29 determines that the detected air volume is lower than a reference air volume corresponding to the corrected rotation speed and that the detected air volume is lower than a predetermined air volume determined corresponding to the reference air volume, a stop command unit 31 stops the combustion operation. Therefore, the progress of the clogging of the exhaust port 20 can be easily detected. If there is no risk of incomplete combustion or the like even if the clogging of the exhaust port occurs, the clogging of the exhaust port 20 may be erroneously performed. It is not determined that it is in progress.

In this embodiment, after the correction unit 25 corrects the rotation speed of the combustion fan 10, the airflow sensor 13 obtains the rotation speed of the combustion fan 10 corresponding to the rotation speed of the combustion fan 10 detected by the rotation speed sensor 12. It is determined whether or not the detected air flow is larger than the reference air flow corresponding to the corrected rotation speed.
Before correcting the rotation speed of the combustion fan 10 at the reference rotation speed.
May be compared with a detected airflow obtained when the is rotated and a reference airflow corresponding to the reference rotation speed. Furthermore,
In the present embodiment, an example in which the detected air volume is directly compared with the reference air volume is shown.
As shown in the embodiment, the airflow difference calculating means is provided to obtain the value of the difference between the detected airflow and the reference airflow, and the determination unit 29 determines whether or not the airflow difference obtained at this time exceeds a predetermined value. If the airflow difference exceeds a predetermined value, the stop command unit 31 may stop the combustion operation. As described above, the predetermined value is a value of the air flow difference that does not cause a risk of incomplete combustion or the like even if the exhaust port is clogged. Furthermore, although the calculation of the difference between the detected air volume and the reference air volume has been described, the ratio between the detected air volume and the reference air volume may be calculated without being limited to the difference.

In each of the above-described embodiments, the reference air volume and the detected air volume are compared by using the timing at which the combustion fan 10 is constantly rotated at a predetermined rotation speed during pre-purge and mild ignition of the burner. Although a configuration that simplifies the operation by judging the degree of clogging of the cylinder 20 is employed, the present invention is not limited to such a configuration. Needless to say, a configuration may be adopted in which the degree of clogging of the exhaust port 20 is determined by comparing the air volume.

[0059]

As is clear from the above description, the present invention provides a method for controlling the ratio of the reference airflow to the detected airflow when the difference between the reference airflow and the detected airflow exceeds a predetermined value. When the value of exceeds the predetermined value, when the change amount of the rotation speed of the combustion fan when the detected air volume matches the reference air volume exceeds the predetermined amount, the detected air volume falls below the predetermined air volume smaller than the reference air volume. In any one of the cases, it is determined that the exhaust port is likely to be blocked due to incomplete combustion, and the combustion operation can be automatically stopped.

Further, since the operation stop means operates at the beginning of the combustion operation, particularly at the time of pre-purge or at the time of slow ignition of the burner, the degree of clogging of the exhaust port can be determined at an early stage. Since the operation of the means is performed when the number of revolutions of the combustion fan 10 is controlled to be constant at the time of pre-purge or at the time of slow ignition of the burner, the operation of the operation stopping means can be performed with a simple configuration.

If the exhaust port is normal without clogging, or if the degree of clogging is small and there is no risk of incomplete combustion, the air flow rate detected by the air flow rate sensor is adjusted to the set air flow rate corresponding to the required combustion amount of the burner. By controlling the number of revolutions of the combustion fan by the fan control means so as to match, the combustion operation can be performed smoothly. Therefore, an accurate operation can be performed according to the degree of clogging of the exhaust port, and a combustion device excellent in safety and usability can be provided.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a combustion apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a main part of the combustion device of FIG. 1;

FIG. 3 is a diagram showing the relationship between the number of revolutions of a combustion fan and the amount of air.

FIG. 4 is a block diagram of a main part of a combustion apparatus according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a main part of a combustion apparatus according to a third embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the number of rotations of a combustion fan and the amount of air.

[Explanation of symbols]

3 ... burner, 19 ... combustion chamber, 10 ... combustion fan, 13 ...
Air flow sensor, 20 ... exhaust port, 23 ... fan control means, 2
4... Reference rotation speed setting unit (predetermined rotation speed setting means), 26.
Storage unit (storage unit), 27 ... Readout unit (reading unit), 28
... Airflow difference calculating unit (operation stopping means), 29 ... determining unit (operation stopping means), 31 ... Stop commanding unit (operation stopping means), 32
... Rotation speed change amount calculation unit (operation stop means).

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-118532 (JP, A) JP-A-5-118538 (JP, A) JP-A-4-41949 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) F23N 3/08 F23N 5/18 101 F23N 5/24 104

Claims (2)

(57) [Claims] 1. A combustion chamber containing a burner, an exhaust port communicating with the combustion chamber, a combustion fan for blowing combustion air to the burner, and an air flow sensor for detecting an air flow from the combustion fan to the burner. , The rotation for detecting the rotation speed of the combustion fan
A number sensor, and fan control means for controlling the number of revolutions of the combustion fan so that a detected air volume detected by the air volume sensor during the burn operation of the burner matches a set air volume for obtaining a required combustion volume of the burner. A combustion device provided with: a storage unit in which data indicating a relationship between a rotation speed of the combustion fan and a reference airflow obtained in a normal state based on the rotation speed is stored in advance; and a rotation speed of the combustion fan obtained by the rotation speed sensor. reading means for reading the reference air amount corresponding from said storage means, detecting air amount obtained by the air volume sensor in response to the rotational speed of the combustion fan obtained by the rotational speed sensor is the
If less than the reference air amount corresponding to the rotational speed, determine the ratio between the detected air amount and the reference air amount when the value of the ratio exceeds a predetermined value, the operation stop means for stopping the combustion operation of the burner A combustion device comprising: 2. A combustion chamber accommodating a burner, an exhaust port communicating with the combustion chamber, a combustion fan for blowing combustion air to the burner, and an air flow sensor for detecting an air flow from the combustion fan to the burner. A rotation speed sensor for detecting a rotation speed of the combustion fan, and the combustion fan for adjusting a detection air flow detected by the air flow sensor during combustion operation of the burner to a set air flow for obtaining a required combustion amount of the burner. of the combustion apparatus comprising a fan control means for controlling the rotational speed, a memory means in which data is stored in advance showing the relationship between the engine speed and the reference air amount obtained in the normal by the rotational speed of the combustion fan, the reading means for reading the reference air quantity corresponding to the rotational speed of the combustion fan obtained by the rotational speed sensor from the storage means, and the set air volume to said fan control means Te when obtaining the detected air volume that matches the reference air volume giving the reference air volume
When the rotational speed of the combustion fan exceeds the speed corresponding to the reference air amount, calculated the amount of change rotational speed from the ratio of both speed when the change amount exceeds a predetermined amount, combustion operation of the burner A combustion stopping device for stopping the combustion.