JPH0814545A - Combustion device - Google Patents

Abstract

PURPOSE:To provide a combustion device, capable of recognizing the clogging of an exhaust port while discriminating it from the clogging of a feed air port and effecting correct operation in accordance with the clogging of the exhaust port. CONSTITUTION:A combustion device is provided with an air volume changing amount detecting means 26, obtaining a difference between an initial detecting air volume obtained by an air volume sensor 13 corresponding to a predetermined number of rotation of a combustion fan 10 in the initial period of starting of combustion operation and a detecting air volume during combustion, which is obtained by an air volume sensor 13 corresponding to the predetermined number of rotation of the combustion fan 10, and an operation stopping means 27, stopping the combustion operation when the difference of the detecting air volume has exceeded a predetermined value. When the exhaust port is clogged, the difference of the detected air volume exceeds a predetermined value and the combustion operation is stopped automatically and when a trouble except the clogging of the exhaust port is generated, the combustion operation is continued. In the combustion operation, the number of rotation of the combustion fan 10 is controlled so that the detecting air volume of the air volume sensor 13 coincides with a set air volume.

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 For example, in a water heater, the burner combustion amount required to match the hot water temperature detected by a hot water temperature sensor with a set temperature set by a user is obtained every moment, and the burner is burned. The rotation speed of the combustion fan for supplying combustion air is controlled to an instruction rotation speed determined according to the required combustion amount, and the fuel to the burner is supplied according to the required combustion amount or the actual rotation speed of the combustion fan. It is generally known to control the opening of a proportional valve provided in a supply path.

In this type of combustion apparatus, it is assumed that the rotation speed of the combustion fan and the air flow amount (air supply amount) from the combustion fan to the burner always correspond to each other in a fixed relationship. Although it is controlled to the instructed rotation speed, in practice, if the load of the combustion fan changes from the initial normal case due to clogging of the air supply port or exhaust port of the combustion chamber accommodating the burner, etc. Even if the rotation speed of the combustion fan is the same, the actual air volume from the combustion fan to the burner changes compared with the normal case.

For this reason, in recent years, the actual air volume to the burner is momentarily detected by an air volume sensor arranged in the air passage from the combustion fan to the burner, and the detected air volume corresponds to the required combustion volume of the burner. It has been proposed to control the number of revolutions of the combustion fan so as to coincide with the above (for example, Japanese Utility Model Laid-Open No. 1-129561, Japanese Utility Model Laid-Open 60-).
(See Japanese Patent No. 143251).

By controlling the rotation speed of the combustion fan by using the air flow sensor as described above, even if the air supply port and the exhaust port of the combustion chamber are blocked to some extent, the air flow rate corresponding to the required combustion amount of the burner can be controlled. Although it is possible to supply the burner from the combustion fan, the following inconvenience occurs especially when the exhaust port is clogged to some extent.

That is, for example, in a gas water heater, when the exhaust port is clogged to some extent, the exhaust in the combustion chamber is not smoothly performed, so that the air pressure in the combustion chamber increases. In this case, by controlling the combustion fan so that the air flow from the combustion fan to the burner matches the set air flow using the air flow sensor as described above, the air flow to the burner corresponds to the required combustion amount of the burner. Although you can
Even if the opening of the proportional valve is controlled to supply the burner with a fuel gas corresponding to the air volume, the atmospheric pressure in the combustion chamber becomes higher than the pressure of the fuel gas, so that the fuel gas is less likely to be ejected from the burner. Become. For this reason, it becomes difficult to supply the burner with an amount of fuel gas commensurate with the amount of air flowing into the burner, which makes it difficult to obtain an appropriate amount of combustion and incomplete combustion may occur. Further, when the exhaust port is clogged to some extent, a part of the exhaust gas may not be exhausted from the combustion chamber through the exhaust port to a proper place such as outdoors, and may leak to an inappropriate place such as indoors. is there.

Therefore, when the exhaust port of the combustion chamber is clogged, it is automatically grasped by some method,
It was desired to stop the combustion operation. Incidentally, when the air supply port is clogged, even if it progresses to some extent, the above-mentioned inconvenience does not occur, and therefore it is preferable to continue the combustion operation.

Based on such a background, the present inventors have examined the relationship between the rotational speed of the combustion fan and the actual air flow rate when the exhaust port and the air supply port are clogged. I obtained such knowledge.

That is, the relationship between the rotation speed of the combustion fan and the actual air flow is that there is no clogging of the exhaust port or the air supply port,
In the normal state, the relationship is as shown by the solid line a in FIG. When the exhaust port or the air supply port is clogged, for example, the relationship shown by the solid line b in FIG. 5 is obtained, and the air volume at any rotation speed is smaller than in the normal case (solid line a). Become. In this case, the inclination of the solid line b (the value of the ratio of the air volume to the rotation speed) is basically smaller as the degree of clogging of the exhaust port or the air supply port is smaller, but this tendency is
The same applies to the case where the exhaust port or the air supply port is clogged.

On the other hand, in one combustion operation, when the air supply port is clogged, the relationship between the rotation speed of the combustion fan and the actual air volume does not change much from the beginning to the end of the combustion operation. However, when the exhaust port is clogged, the relationship between the rotation speed of the combustion fan and the actual air volume was, for example, the relationship shown by the solid line b at the beginning of the combustion operation, but the combustion operation progresses. Then, for example, the relationship is as shown by a virtual line c in FIG. That is, in the case of clogging of the exhaust port, the air volume at any rotation speed is relatively lower at the stage of the combustion operation than at the initial stage of the combustion operation, and the rotation speed and air volume of the combustion fan are The slope of the straight line indicating the relationship is relatively large when the combustion operation progresses to a certain extent compared with the initial stage of the combustion operation.
The reason for this is considered as follows. That is, as the combustion operation progresses, the temperature in the combustion chamber rises significantly relative to the initial stage of the combustion operation, and the exhaust gas expands. Then, when the exhaust port is clogged, the exhaust resistance also greatly increases, the load of the combustion fan increases, and the air volume at any rotation speed decreases relatively more than in the initial stage of the combustion operation. On the other hand, when the air supply port is clogged, the exhaust is smoothly performed, so that even if the combustion operation proceeds, the temperature of the exhaust gas does not rise much compared to the beginning of the combustion operation, and the combustion fan The relationship between the rotational speed and the actual air volume does not change much from the beginning to the end of the combustion operation.

Therefore, in the combustion operation, the actual air flow rate at any given rotation speed or the value of the ratio of the air flow rate to the rotation speed is monitored at the initial stage of the combustion operation and at a stage where it has advanced to some extent, and the change is observed. It is considered possible to distinguish clogging of the exhaust port from clogging of the air supply port.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and in a combustion apparatus for controlling the rotation speed of a combustion fan so that the air volume detected by an air volume sensor matches a set air volume, An object of the present invention is to provide a combustion device capable of distinguishing clogging of a mouth from clogging of an air supply port and performing an appropriate operation accordingly.

[0013]

To achieve the above object, a first aspect of the present invention is directed to a combustion chamber accommodating a burner, an air supply port and an exhaust port communicating with the combustion chamber, and the burner. A combustion fan provided on the side of the air supply port to blow combustion air to the air, an air volume sensor for detecting an air volume from the combustion fan to the burner, and a detection detected by the air volume sensor during combustion operation of the burner. A combustion device comprising: a fan control unit that controls a rotation speed of the combustion fan so as to match an air flow with a set air flow for obtaining a required combustion amount of the burner, wherein the combustion fan is provided at an initial stage of a combustion operation of the burner. To the air flow sensor corresponding to a predetermined rotation speed of the combustion fan during the combustion of the burner after the initial detected air flow obtained by the air flow sensor corresponding to the predetermined rotation speed of The amount of change between the detected detected air flow during combustion and the amount of change in air flow, and the amount of change between the initial detected air flow and the detected air flow during combustion obtained by the calculated air flow change amount is a predetermined amount. And an operation stopping means for stopping the combustion operation when the temperature exceeds the limit.

The fan control means stores the relationship between the air flow rate and the rotation speed of the combustion fan when the load of the combustion fan is normal as reference data, and stores the storage means in advance, and the reference when the burner burns. A reference rotation speed setting means for obtaining a reference rotation speed of the combustion fan corresponding to the set air volume based on the data, and a deviation calculation means for obtaining a deviation between the set air volume and the detected air volume obtained by the air volume sensor, The detected air volume is set by correcting the rotational speed of the combustion fan according to the deviation between the set air volume and the detected air volume while controlling the rotational speed of the combustion fan with the reference rotational speed as a reference instruction rotational speed. The combustion fan is controlled so as to match the air flow rate, and the air flow rate change amount calculation means sets the reference rotation speed in the initial stage of the combustion operation of the burner. An initial deviation obtained by the deviation calculating means corresponding to a predetermined set air volume that is the predetermined rotation speed, and a combustion deviation obtained by the deviation calculating means corresponding to the predetermined set air volume during combustion of the burner. Is calculated as a change amount between the initial detected air volume and the detected air volume during combustion.

Further, the fan control means controls the rotation speed of the combustion fan to the predetermined rotation speed at the beginning of the combustion operation, and the reference data corresponding to the predetermined rotation speed at the time of the control. And a means for applying the obtained air volume to the deviation computing means as the predetermined set air volume, wherein the air volume change amount computing means is provided when the combustion fan is controlled to the predetermined rotation speed at the beginning of the combustion operation. A means for obtaining the deviation output from the deviation calculating means as the initial deviation, and the combustion at the reference rotation speed corresponding to the set air volume for obtaining the required combustion quantity by the fan control means during the subsequent combustion of the burner. The deviation (N0 / Nx) of the ratio between the reference rotation speed (Nx) and the predetermined rotation speed (N0) is added to the deviation output from the deviation calculating means when the fan is controlled. Characterized in that it comprises a means for determining the combustion deviation by multiplying.

Alternatively, the fan control means includes means for controlling the number of revolutions of the combustion fan to the predetermined number of revolutions at an initial stage of starting the combustion operation, and the air volume change amount computing means is provided at an initial stage of starting the combustion operation. , A means for obtaining, as the initial detected air volume, the air volume detected by the air volume sensor when the combustion fan is controlled to the predetermined rotational speed, and the actual rotational speed (N) of the combustion fan during the subsequent combustion of the burner.
x) and the predetermined number of revolutions (N0) (N0 / Nx)
) Is multiplied by the air volume detected by the air volume sensor at the actual number of revolutions (Nx) to obtain the air volume detected during combustion.

Further, the fan control means controls the number of revolutions of the combustion fan to the predetermined number of revolutions during pre-purge or during slow ignition of the burner.

In order to achieve the above-mentioned object, a second aspect of the present invention is a combustion chamber accommodating a burner, an air supply port and an exhaust port communicating with the combustion chamber, and a burner for combustion in the burner. A combustion fan provided on the air inlet side to blow air, an air volume sensor for detecting an air volume from the combustion fan to the burner, and a detected air volume detected by the air volume sensor during combustion operation of the burner are described above. In a combustion device including fan control means for controlling the rotation speed of the combustion fan so as to match the set air flow for obtaining the required combustion amount of the burner, in the combustion operation, the air flow sensor for the rotation speed of the combustion fan A first calculation means for obtaining a ratio value of the detected air flow rate, a ratio value (H0) obtained by the first calculation means at the initial stage of starting the combustion operation of the burner, and the subsequent combustion of the burner. Second determining the amount of change between the resulting ratio value (H1) by the first computing means in the medium
And an operation stopping means for stopping the combustion operation when the amount of change in the ratio values (H0, H1) obtained by the second calculating means exceeds a predetermined amount. And

Further, the ratio value (H0) at the initial stage of starting the combustion operation of the burner is the ratio value at the time of pre-purge or at the time of slow ignition of the burner.

[0020]

In the first aspect of the present invention, when the exhaust port is clogged and progresses to some extent, the detected air volume obtained by the air volume sensor at an arbitrary rotation speed of the combustion fan is: As the combustion operation progresses, the amount of air detected in the initial stage of the combustion operation decreases relatively large.
Therefore, when the amount of change between the initial detected air amount and the detected air amount during combustion at the predetermined number of revolutions becomes large, and the amount of change exceeds a predetermined amount, the exhaust port clogging progresses to some extent and combustion operation is performed. It is possible to determine that there is a risk that this will hinder the operation. Then, in such a case, by stopping the combustion operation by the operation stopping means, a situation in which an inappropriate combustion operation is performed is eliminated.
When the exhaust port is normal and the air supply port is clogged, the amount of change between the initial detected air amount and the in-combustion detected air amount does not become so large and remains below the predetermined amount. . Therefore, at this time, the combustion operation continues without stopping. Then, in this case, the combustion operation is properly performed by controlling the rotation speed of the combustion fan so that the detected air volume obtained by the air volume sensor matches the set air volume.

In this case, the control by the fan control means for making the air volume detected by the air volume sensor equal to the set air volume during the combustion operation is performed, for example, by the air volume and the rotational speed of the combustion fan when the load of the combustion fan is normal. The relationship is stored in advance as reference data, and the set air volume is controlled while controlling the combustion fan with the reference rotation speed, which is obtained corresponding to the set air flow based on the reference data during combustion operation, as the reference instruction rotation speed. This is performed by correcting the rotation speed of the combustion fan according to the deviation between the detected air volume and the detected air volume. In this case, in the initial stage of starting the combustion operation of the burner, the reference rotation speed corresponds to a predetermined set air volume at which the combustion fan has a predetermined rotation speed, and the deviation obtained by the deviation calculation means and the combustion of the burner. By obtaining the difference between the deviation obtained by the deviation calculating means corresponding to the predetermined set air volume in the inside, the difference between the initial detected air volume and the burning detected air volume is the change amount between the detected air volumes. Desired. That is, for example, when the predetermined air volume is given to the fan control means at the beginning of combustion operation, the fan control means first controls the rotation speed of the combustion fan to the predetermined rotation speed, and at this time, the deviation calculation is performed. The initial deviation obtained by the means is a deviation between the predetermined set air volume and the initial detected air volume. Similarly, when the predetermined set air volume is given to the fan control means during combustion, the fan control means first controls the rotation speed of the combustion fan to the predetermined rotation speed, and at this time, the deviation calculation means. The in-combustion deviation obtained by is the deviation between the predetermined set air volume and the in-combustion detected air volume. Therefore, the difference between these deviations becomes the difference between the initial detected air volume and the detected air volume during combustion, and this corresponds to the amount of change between the detected air volumes. In this way, the deviation calculation means of the fan control means that controls the detected air volume of the air volume sensor to match the set air volume is effective for obtaining the amount of change (difference) between the initial detected air volume and the detected air volume during combustion. Be utilized.

Further, the fan control means controls the rotation speed of the combustion fan to the predetermined rotation speed at the beginning of the combustion operation, and the reference data corresponding to the predetermined rotation speed at the time of the control. When the means for applying the obtained air volume to the deviation computing means as the predetermined set air volume is provided, first, from the deviation computing means when the combustion fan is controlled to the predetermined number of revolutions at the beginning of the combustion operation. The output deviation is obtained as the initial deviation. Then, during the subsequent combustion, the set air volume for obtaining the required combustion amount is given to the fan control means, and the fan control means controls the rotation speed of the combustion fan so that the air volume detected by the air volume sensor matches the set air volume. Control. In this case, generally, the set air volume for obtaining the required combustion amount is different from the predetermined set air volume, and therefore, when the set air volume for obtaining the required combustion amount is given to the fan control means, the fan control means Although the rotation speed of the combustion fan to be controlled (= reference rotation speed) is not necessarily the predetermined rotation speed, the deviation between the set air volume and the detected air volume obtained by the deviation calculating means at that time is the rotation of the combustion fan. It is almost proportional to the number (see FIG. 5). Therefore, when obtaining the in-combustion deviation, the deviation output from the deviation calculating means when the combustion fan is controlled to the reference rotation speed corresponding to the set air volume for obtaining the required combustion amount by the fan control means , The in-combustion deviation is presumed by a proportional calculation by multiplying the value (N0 / Nx) of the ratio of the reference rotation speed (Nx) and the predetermined rotation speed (N0). Then, by comparing the difference between the in-combustion deviation thus obtained and the initial deviation with the predetermined amount, the clogging of the exhaust port can be grasped. Further, if the in-combustion deviation is calculated in this manner, during the combustion of the burner, the combustion is always performed so that the set air volume corresponding to the required combustion volume is obtained regardless of the predetermined set air volume and the predetermined rotation speed. It is possible to control the rotation speed of the fan.

In the first aspect of the present invention, the amount of change between the initial detected air volume and the air volume during combustion is calculated without using the deviation obtained by the deviation calculation means of the fan control means as described above. It is also possible. That is, the initial detected air volume is obtained by the air volume sensor by controlling the number of revolutions of the combustion fan to the predetermined number of revolutions at the beginning of combustion operation. Regarding the detected air volume during combustion, the actual air volume of the combustion fan is approximately proportional to the rotational speed at any time during combustion of the burner (see FIG. 5). Therefore, if the air volume detected by the air volume sensor at a certain point during combustion is multiplied by the ratio value (N0 / Nx) between the actual rotation speed (Nx) of the combustion fan at that time and the predetermined rotation speed (N0), it is proportional. By the calculation, the detected air volume during combustion at the predetermined rotation speed (N0) is presumably obtained. Then, by comparing the amount of change between the combustion detected air volume thus obtained and the initial detected air volume with the predetermined amount,
As described above, it is possible to grasp the clogging of the exhaust port. Further, if the detected air volume during combustion is calculated in this way, during the combustion of the burner, the set air volume corresponding to the required combustion volume is always irrespective of the predetermined number of revolutions for obtaining the detected air volume during combustion. It is possible to control the rotation speed of the combustion fan so as to obtain the value. The detected air volume during combustion can be obtained from the air volume sensor, for example, by controlling the rotation speed of the combustion fan to the predetermined rotation speed at any time during the combustion of the burner.

Further, when controlling the number of revolutions of the combustion fan to the predetermined number of revolutions at the beginning of the combustion operation, it is preferable to perform it at the time of pre-purge and at the time of gentle ignition of the burner. In this way, in order to obtain the initial detected air volume, after the combustion of the burner is started, the fan control means performs appropriate air volume control of the combustion fan, so that the initial detected air volume is obtained at a suitable timing. It becomes possible.

Next, in the second aspect of the present invention, when the exhaust port is clogged and progresses to some extent, the ratio of the air volume detected by the air volume sensor to the rotation speed of the combustion fan is determined. The value, that is, the slope of the straight line showing the relationship between the rotation speed of the combustion fan and the air volume, decreases relatively greatly with respect to the detected air volume in the initial stage of the combustion operation as the combustion operation proceeds. Therefore, the amount of change between the ratio value (H0) at the beginning of the combustion operation and the subsequent ratio value (H1) during combustion of the burner becomes large, and the amount of change exceeds a predetermined amount. In this case, it can be determined that the exhaust port is clogged to some extent, which may interfere with the combustion operation. Then, in such a case, by stopping the combustion operation by the operation stopping means, a situation in which an inappropriate combustion operation is performed is eliminated. In this case, since the ratio values (H0, H1) do not depend on the rotation speed of the combustion fan, the ratio values (H0, H1)
When determining, the rotation speed of the combustion fan may be arbitrary. When the exhaust port is normal and the air supply port is clogged, the value of the ratio of the detected air volume to the rotation speed does not change much between the start of combustion operation and the subsequent combustion, The amount of change in the value of the ratio between the two remains below the predetermined amount. Therefore, at this time, the combustion operation continues without stopping. Then, in this case, the combustion operation is properly performed by controlling the rotation speed of the combustion fan so that the detected air volume obtained by the air volume sensor matches the set air volume.

The ratio value (H0) at the initial stage of starting the combustion operation of the burner is, for example, the value of the ratio at the time of pre-purge or when the burner is slowly ignited. , The ratio value (H
0) is obtained.

[0027]

EXAMPLE An example of the first aspect of the present invention is shown in FIGS.
A description will be given with reference to FIG. FIG. 1 is a system configuration diagram of the combustion apparatus of this embodiment, and FIG. 2 is a block configuration diagram of a main part of the apparatus of FIG.

Referring to FIG. 1, the combustion apparatus of the present embodiment is a water heater, 1 is a water heater main body having a heat exchanger 2 and a burner 3 for heating the same, and 4 is a 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, and 6 is the outlet temperature of water flowing through the water pipe 4 on the downstream side of the heat exchanger 2. A temperature sensor for detecting the temperature, 7 is a gas supply pipe for supplying gas to the burner 3,
Reference numerals 8 and 9 denote open / close solenoid valves and a gas proportional valve that are sequentially provided in the gas supply pipe 7 from the upstream side, 10 is a combustion fan that blows combustion air to the burner 3, and 11 is a fan motor that drives the combustion fan 10. Reference numeral 12 denotes 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 for detecting the air flow rate from the combustion fan 10 to the burner 3, and reference numeral 14 denotes a user's hot water temperature. An operation unit for performing settings and the like, 15 is a fan motor 11, a solenoid valve 8, and a gas proportional according to the set temperature of the hot water set by the operation unit 14 and the detection signals of the sensors 5, 6, 12, and 13 described above. A controller that controls the valve 9 and the like, 16 is an igniter for igniting the burner 3, and 17 is a frame rod that detects a combustion state of the burner 3 such as whether or not there is a misfire.

The burner 3 is housed in the combustion chamber 18 formed in the water heater main body 1 below the heat exchanger 2, and the combustion chamber 18 has an exhaust port 19 provided in the upper portion of the water heater main body 1.
And the air supply port 20 provided in the lower portion communicate with each other. Further, the combustion fan 10 is provided on the air supply port 20 side, and the air flow sensor 13 is arranged in the air passage 21 from the air supply port 20 to the combustion chamber 18.

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) of a kitchen or a bathroom. Further, the air volume sensor 13 is
For example, it is a hot wire air flow sensor. In addition, the air flow sensor,
In addition to the hot wire type, there are a heat type, a Karman vortex type, a vane type and the like.

Referring to FIG. 2, the controller 15 is composed of an electronic circuit including a microcomputer and the like, and the functional configuration thereof includes a set temperature given from the operating section 14 and an incoming water temperature sensor ( The required combustion amount of the burner 3 required to match the outlet heated water temperature detected by (not shown), the outlet heated water temperature detected by the temperature sensor 6, and the flow rate detected by the flow sensor 5 with the set temperature. And a flow rate from the combustion fan 10 to the burner 3 corresponding to the required combustion amount calculated by the calculation unit 22 (combustion air supply amount)
And a fan control unit that controls the rotation speed of the combustion fan 10 via the fan motor 11 according to the detected air volume detected by the air volume sensor 13 and the set air volume set by the air volume setting unit 23. 24, a valve control unit 25 that controls the opening of the gas proportional valve 9 according to the rotation speed of the combustion fan 10 detected by the rotation speed sensor 12, and the like, and controls the gas supply amount to the burner 3, The air flow sensor 1 detects the air flow rate (initially detected air flow rate) at the beginning of the operation (hot water supply operation) and the air flow rate sensor 1 during combustion of the burner 3.
3 is obtained by the air volume change amount calculation unit (air volume change amount detection means) 26 for obtaining the difference between the detected air volume (combustion detected air volume) 3 as the amount of change between the detected air volumes. A stop command unit 27 that stops the combustion fan 10 via the fan control unit 24 according to the difference between the initial detected air amount and the detected air amount during combustion, and shuts off the gas supply to the burner 3 via the solenoid valve 8. It has and.

Here, corresponding to the configuration of the first aspect of the present invention, the fan control section 24 constitutes the fan control means 28 together with the fan motor 11 and the rotation speed sensor 12, and the stop command section 27 is an electromagnetic wave. The operation stop means 27a is configured together with the valve 8 and the fan control unit 24. Then, the fan control unit 24 includes a deviation calculation unit (deviation calculation means) 2 for obtaining a deviation between the set air volume and the air volume detected by the air volume sensor 13.
9, a storage unit (storage means) 30 that stores and holds in advance reference data indicating the relationship between the air flow rate and the rotation speed of the combustion fan 10, and a combustion fan corresponding to the set rotation speed based on the reference data. A reference rotation speed setting unit (reference rotation speed setting means) 31 for obtaining the reference rotation speed of 10 and a correction unit 32 for correcting the rotation speed of the combustion fan 10 according to the deviation obtained from the deviation calculation unit 29. ing.
The reference data stored and held in the storage unit 30 is the data shown by the solid line a in FIG.

Further, the air flow rate change amount calculation unit 26 calculates the deviation (initial deviation) obtained from the deviation calculation unit 29 at the initial stage of starting the combustion operation, and the deviation calculation during combustion of the burner 3. During-combustion deviation extraction unit 34 for obtaining deviation during combustion by extracting deviation obtained from unit 29
And a subtraction unit 35 for obtaining a difference between the initial deviation and the in-combustion deviation as a difference between the initial detected air quantity and the in-combustion detected air quantity.
It has and.

When the water flow through the water pipe 4 is started, the controller 15 detects this through the flow rate sensor 5,
In response to the detection of the water flow, the fan control unit 24 rotationally drives the combustion fan 10 via the fan motor 11, and at the same time opens the solenoid valve 8 of the gas supply pipe 7 to start the gas supply to the burner 3. Further, the burner 3 is ignited via the igniter 16, whereby the combustion operation (hot water supply operation) of the burner 3 is started. Then, at this time, the fan control unit 24 sets the combustion fan 10 prior to ignition of the burner 3.
Is rotated at a predetermined number of revolutions (about 50% of the maximum number of revolutions) for a certain period of time, pre-purge is performed, and then the burner 3 is slowly ignited.

When it is detected that the water flow through the water pipe 4 is stopped, the controller 15 closes the electromagnetic valve 8 to shut off the gas supply to the burner 3 and causes the fan controller 24 to burn the gas. The fan 10 is stopped and the hot water supply operation is stopped. The operation of terminating the hot water supply operation is also performed when the flame rod 17 detects a misfire of the burner 3 during the hot water supply operation.

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

As described above, when starting the hot water supply operation,
The controller 15 causes the fan controller 24 to rotate the combustion fan 10 at a predetermined rotation speed N0 shown in FIG.
In this state, the prepurge and the slow ignition of the burner 3 are performed. At this time, the air volume setting unit 23 gives the set air volume Fa0 corresponding to the predetermined rotation speed N0 to the deviation calculation unit 29 of the fan control unit 24 in the reference data indicated by the solid line a in FIG.
The deviation calculator 29 calculates the deviation between the set air volume Fa0 and the detected air volume obtained by the air volume sensor 13 at this time. In this case, when the air supply port 20 and the exhaust port 19 are clogged, the relationship between the rotation speed of the combustion fan 10 and the air volume is as shown by the solid line b in FIG. 5, for example. At this time, the detected air volume is "Fb0"(<Fa0), and the deviation calculated by the deviation calculator 29 is (Fa0-
Fb0).

Then, the initial deviation extraction unit 33 of the airflow change amount calculation unit 26 sets the deviation (Fa0-Fb0) obtained by the deviation calculation unit 29 at the time of pre-purge at the initial stage of the start of the hot water supply operation (combustion operation). The deviation is extracted and stored in a memory (not shown).

Next, when the burner 3 is ignited and the combustion operation is started, the controller 15 causes the required combustion amount calculation unit 22 to bring the hot water temperature detected by the temperature sensor 6 to the set temperature set by the operation unit 14. The required combustion amount of the burner 3 required to make the coincidence is obtained every moment based on the detection data of the incoming water temperature, the outgoing hot water temperature, the flow rate, and the like. Further, the air flow rate setting unit 23 of the controller 15 sets the air flow rate from the combustion fan 10 to the burner 3 corresponding to the required combustion amount calculated by the required combustion amount calculation unit 22 according to a predetermined data table or the like, and sets it. Fan control unit 24
Give to.

At this time, the fan control section 24 is set by the reference rotation speed setting section 31 based on the reference data (data shown by the solid line a in FIG. 5) stored and held in the storage section 30. The reference speed corresponding to the air volume is set to the combustion fan 1
It is set as a reference instruction rotational speed of 0. Specifically, FIG.
When the given set air volume is "Fax", the reference rotation speed Nx is set as the reference instruction rotation speed. Then, the fan control unit 24 basically monitors the actual rotation speed of the combustion fan 10 by the rotation speed sensor 12 and feeds back the rotation speed of the combustion fan 10 so that it becomes the reference instruction rotation speed Nx. Control.

In this case, if the exhaust port 19 and the air supply port 20 are not clogged and the load of the combustion fan 10 is normal, the above-described control is performed to detect the air volume detected by the air volume sensor 13. That is, the actual air volume to the burner 3 is the set air volume Fax. However, the exhaust port 19
If the relationship between the rotation speed of the combustion fan 10 and the air volume is such as shown by the solid line b in FIG. 5, the rotation speed of the combustion fan 10 is set to the above value. Even if it is controlled to the standard rotation speed Nx, the air volume sensor 13 at that time
The detected air volume obtained by is "Fbx"(<Fax),
It does not match the set air volume Fax. Then, in such a case, the fan control unit 24 causes the deviation (Fax−) between the set air flow rate Fax and the detected air flow rate Fbx obtained by the deviation calculation unit 29.
Fbx), the correction unit 32 corrects the rotation speed of the combustion fan 10 based on the reference instruction rotation speed Nx.
As a result, the rotational speed of the combustion fan 10 is corrected and controlled to the rotational speed Nxb (see FIG. 5) so that the detected air volume eventually matches the set air volume Fax.

On the other hand, the valve controller 25 of the controller 15
In parallel with controlling the combustion fan 10 as described above, controls the opening of the gas proportional valve 9 to control the gas supply amount to the burner 3. In this case, basically, the valve control unit 2
5 is a combustion fan 1 detected by the rotation speed sensor 12.
The opening of the gas proportional valve 9 is controlled according to the actual rotational speed of zero. Therefore, when the exhaust fan 19 is not clogged and the load of the combustion fan 10 is normal, the rotation speed of the combustion fan 10 and the actual air volume correspond to each other, and the combustion is performed as described above. By controlling the opening of the gas proportional valve 9 according to the rotation speed of the fan 10, the gas supply amount to the burner 3 corresponds to the air volume to the burner 3 controlled to the set air volume, and the burner 3 Combusts with the required combustion amount.

However, for example, the exhaust port 19 and the air supply port 20
When the clogging of the combustion fan 10 occurs, the rotation speed of the combustion fan 10 is controlled so that the detected air volume and the set air volume match as described above, and therefore, even if the air volume to the burner 3 is the same, The rotation speed of the fan 10 increases or decreases. Therefore, even if the air flow rate to the burner 3 is the same even if the opening of the gas proportional valve 9 is simply controlled according to the rotation speed of the combustion engine 10,
The opening degree of the gas proportional valve 9 changes following the rotation speed of the combustion fan 10, and the gas supply amount to the burner 3 changes.

Therefore, the valve control unit 27 of the controller 14
In order to offset the correction of the rotation speed of the combustion fan 10, when the air volume detected by the air volume sensor 13 is smaller than the set air volume, the rotation speed of the combustion fan 10 is increased by the fan controller 24. The opening of the valve 9 is set to the combustion fan 10
Is less than the opening according to the number of revolutions of
The opening of the gas proportional valve 9 is made larger than the opening corresponding to the rotation speed of the combustion fan 10. As a result, the gas supply amount to the burner 3 corresponds to the actual air amount (detected air amount) to the burner 3, and the burner 3 burns smoothly with the required combustion amount.

During such a combustion operation, the in-combustion deviation extraction unit 34 of the air flow rate change amount calculation unit 26 causes the combustion fan 10 to be controlled by the fan control unit 24 by the fan control unit 24, as described above. Is the reference rotation speed,
When controlled to the reference speed, the in-combustion deviation extraction unit 34 then extracts the deviation between the set air volume and the detected air volume obtained by the deviation calculation unit 29, and the in-combustion combustion is performed from the deviation as described below. Find the deviation. That is, referring to FIG. 5, at a certain point in time during the above-described combustion operation, the relationship between the rotation speed of the combustion fan 10 and the air volume is, for example, as indicated by a virtual line c in FIG. If there is a relationship, in this state, for example, when the set air volume Fax is given to the fan control unit 24, the fan control unit 24 first
The rotation speed of the combustion fan 10 is controlled to the reference rotation speed Nx corresponding to the set air volume Fax. At this time, the air volume sensor 13
The detected air flow rate is "Fcx", and the deviation calculated by the deviation calculator 29 is (Fax-Fcx). This deviation (Fax
-Fcx) is extracted by the in-combustion deviation extraction unit 34. Then, the in-combustion deviation extraction unit 34 calculates the initial deviation at the time of starting the combustion operation, as described above, with the rotational speed (= reference rotational speed Nx) of the combustion fan 10 currently detected by the rotational speed sensor 12. The part 33 causes the initial deviation (Fa0-F
The value (N0 / Nx) of the ratio to the predetermined rotation speed N0 of the combustion fan 10 when b0) is extracted is calculated, and the value of the ratio (N0 / Nx)
0 / Nx) is multiplied by the deviation (Fax-Fcx), and the value obtained by the multiplication is obtained as the deviation during combustion. The in-combustion deviation thus obtained is, as is clear with reference to FIG. 5, the current state (state of the virtual line c in FIG. 5).
In the above, the deviation obtained by the deviation calculator 29 when the rotation speed of the combustion fan 10 is controlled to the predetermined rotation speed N0 by the set air volume Fa0 when the initial deviation (Fa0-Fb0) is extracted is calculated by proportional calculation. It is estimated. Therefore, in the combustion deviation, when the detected air volume of the air volume sensor 13 is Fc0 when the combustion fan 10 is driven at the predetermined rotation speed N0 in the state of the virtual line c in FIG.
(Fa0-Fc0).

When the in-combustion deviation (Fa0-Fc0) is obtained in this way, the airflow change amount calculation unit 26 then calculates the initial deviation (Fa0) obtained by the initial deviation calculation unit 33 as described above.
-Fb0) is subtracted by the subtraction unit 35 from the deviation during combustion (Fa0-Fc0). The value obtained by this subtraction is (Fb0-F
c0), the detected air volume Fb0 obtained by the air volume sensor 13 when the rotation speed of the combustion fan 10 is set to the predetermined rotation speed N0 at the start of the combustion operation, and the rotation speed of the combustion fan 10 during combustion of the burner 3. It shows a difference from the detected air flow rate Fc0 obtained by the air flow sensor 13 when the predetermined rotation speed is N0.

In this combustion operation, when the exhaust port 19 is clogged, the inclination of the straight line showing the relationship between the rotation speed of the combustion fan 10 and the air volume, or an arbitrary rotation speed, as described above. When the combustion operation of the burner 3 progresses, the air flow rate in the comparative example is relatively greatly reduced compared to the initial case of the combustion operation, and the relationship between the rotation speed of the combustion fan 10 and the air flow shows the initial deviation (Fa0-Fb0). The relationship shown by the solid line b in FIG. 5 at the time of the pre-purge thus obtained becomes the relationship shown by an imaginary line c in FIG. 5 during combustion.

Therefore, in such a case, the difference between the detected air volume Fb0 and the detected air volume Fc0 obtained by the subtraction section 35 becomes relatively large.

On the other hand, when the exhaust port 19 is not clogged or the degree of the clog is small and the air supply port 20 is clogged, the relationship between the rotation speed of the combustion fan 10 and the air volume is the combustion operation. Does not change much from the beginning, and therefore, the difference between the detected air volume Fb0 and the detected air volume Fc0 obtained by the subtraction unit 35 is relatively small. Note that this is the same when both the exhaust port 19 and the air supply port 20 are not clogged and are normal.

Therefore, the stop command unit 2 of the controller 15
7 compares the difference (Fb0-Fc0) between the detected air volume Fb0 and the detected air volume Fc0 obtained by the subtraction unit 35 with a predetermined value, and the difference (Fb0-Fc0) exceeds the predetermined value. In this case, the solenoid valve 8 should be closed and the burner 3
Shut off the gas supply to the fan control unit 24.
The combustion fan 10 is stopped via this, thereby stopping the operation of the water heater. As a result, the water heater automatically stops the combustion operation in a state in which the exhaust port 19 is clogged to some extent and exhaust leakage or incomplete combustion may occur.

It should be noted that the exhaust port 19 is not clogged, and the air supply port 2
When the clogging of 0 has occurred, the difference (Fb0-Fc0) between the detected air flow rate Fb0 and the detected air flow rate Fc0 does not exceed the predetermined value, so that the combustion operation of the water heater continues as described above.

Next, another example of the first aspect of the present invention will be described with reference to FIG.
A description will be given with reference to FIG. FIG. 3 is a block diagram of the essential parts of the apparatus of this embodiment. The apparatus of the present embodiment is a water heater having the same system configuration as that of the water heater of FIG. 1, and in the following description, the same components as those of the water heater of FIG. And detailed description is omitted.

Referring to FIG. 3, in the water heater of the present embodiment, the controller 15 shown in FIG. 1 has the required combustion amount calculation unit 22 and the air flow amount setting unit 23, as in the above-described embodiment. , Fan control unit 24, valve control unit 25, air volume change amount calculation unit (air volume change amount calculation means) 26, and stop command unit 27.
It has. Here, corresponding to the configuration of the first aspect of the present invention, the fan control unit 24 constitutes a fan control unit 28 together with the fan motor 11 and the rotation speed sensor 12, and the stop command unit 27 is an electromagnetic valve. 8 and fan control unit 24
Together with this, the operation stopping means 27a is configured.

In this case, the air volume change amount calculating section 26 extracts the initial detected air volume and the in-combustion detected air volume from the air volume sensor 13, and the in-combustion detected air volume extraction section 37, and their initial detection. And a subtraction unit 38 for obtaining the difference between the air volume and the detected air volume during combustion. Except for the air volume change amount detection unit 26, the other construction and operation are exactly the same as those of the above-mentioned embodiment.

Next, the operation of the water heater according to the present embodiment will be described with a focus on operations different from those of the above-described embodiments.

In the hot water supply apparatus of this embodiment, when the hot water supply operation (combustion operation) is started, the combustion fan 10 is controlled by the fan control unit 24 at the time of the prepurge and the slow ignition of the burner 3 as in the above-described embodiment. It is driven at a predetermined rotation speed N0 via the fan motor 11. At this time, the air volume detected by the air volume sensor 13 is extracted as the initial detected air volume by the initial detected air volume extraction unit 36 and is stored and held in a memory (not shown). Here, when the initial detected air volume is extracted,
The solid line b in FIG. 5 shows the relationship between the rotation speed of the combustion fan 10 and the air volume.
The initial detected air volume to be extracted is Fb0.

Next, when the combustion of the burner 3 is started, the rotation speed of the combustion fan 10 is controlled by the fan control unit 24 so that the set air volume and the air volume detected by the air volume sensor 13 match, as in the above-described embodiment. The opening of the gas proportional valve 8 is controlled by the valve control unit 25 so that the gas is supplied to the burner 3 in an amount corresponding to the flow rate.
Combusts with the required combustion amount.

During the burning of the burner 3, the detected air volume of the air volume sensor 13 is sequentially extracted by the in-combustion detected air volume extraction unit 37. In this case, when the detected air volume is extracted, the rotation speed of the combustion fan 10 is the predetermined rotation speed N of the combustion fan 10 when the initial detected air volume is extracted.
It is not always 0. Therefore, the in-combustion detected air volume extraction unit 37 multiplies the extracted detected air volume by the ratio of the predetermined rotation speed N0 to the rotation speed of the combustion fan detected by the rotation speed sensor 12 at the time of extraction of the detected air flow, thereby obtaining the predetermined airflow. The air volume detected by the air volume sensor 13 at the rotational speed N0 is presumed as the air volume detected during combustion.

Specifically, referring to FIG. 5, assuming that the current relationship between the rotational speed of the combustion fan 10 and the air volume is the relationship shown by the phantom line c in FIG. 5, the rotational speed sensor 12 detects the relationship. Assuming that the number of revolutions of the combustion fan 10 is Nx and the detected air volume detected by the air volume sensor 13 is Fcx, the in-combustion detected air volume extraction unit 37 is a value of the ratio of the predetermined number of revolutions N0 to the actual number of revolutions Nx of the combustion fan 10. By multiplying (N0 / Nx) by the detected air volume Fcx, the air volume Fc0 detected by the air volume sensor 13 at the predetermined rotation speed N0 is obtained as the detected air volume during combustion.

Detected air volume during combustion Fc0 obtained in this way
Is given to the subtraction unit 38 together with the initial detected air volume Fb0, and the subtraction unit 38 obtains the difference (Fb0-FC0) between them.

Here, when the exhaust port 19 is clogged, the relationship between the rotational speed of the combustion fan 10 and the air volume at a certain point during the combustion of the burner 3 is as shown by the solid line b in FIG. The relationship shown in FIG. 4 becomes the relationship shown by the virtual line c in FIG. Therefore, as in the above-described embodiment, the difference in the detected air volume (F
b0-FC0) becomes relatively large.

Therefore, as in the above-described embodiment, the stop command section 27 closes the solenoid valve 8 when the difference (Fb0-FC0) in the detected air volume obtained by the subtraction section 38 exceeds a predetermined value. At the same time, the operation of the combustion fan 10 is stopped via the fan control unit 24, thereby stopping the combustion operation.

When the air supply port 20 is clogged, or when the exhaust port 19 and the air supply port 20 are not clogged normally, the combustion operation is continued as in the above-described embodiment.

In each of the embodiments of the first aspect of the present invention described above, the difference between the initially detected air volume and the in-combustion detected air volume is obtained. However, the ratio between them is used as the initial detected air volume and the in-combustion detected air volume. Alternatively, the combustion operation may be stopped by grasping the clogging of the exhaust port 19 by obtaining the change amount between the above and the predetermined value and comparing it with a predetermined value.

In each of the embodiments of the first aspect,
Although the initial detected air volume is obtained during the prepurge, the initial detected air volume may be obtained when the burner 3 is slowly ignited. Furthermore, the initial detected air volume may be obtained in the initial stage after the combustion of the burner 3 is started. In this case, the initial detected air volume may be presumed by calculation similarly to the in-combustion detected air volume. It is also possible to do so.

In each of the embodiments of the first aspect,
Although the water heater has been described as an example of the combustion device, it goes without saying that the first aspect of the present invention can be applied to other combustion devices such as a fan heater.

In the other embodiment of the first aspect, the rotation speed of the combustion fan 10 for making the set air volume and the detected air volume match is corrected according to the deviation between the set air volume and the detected air volume. However, the rotation speed of the combustion fan 10 may be corrected according to the ratio between the set air volume and the detected air volume.

Next, an example of the second embodiment of the present invention will be described with reference to FIG. 4 and FIG. FIG. 4 is a block diagram of the essential parts of the apparatus of this embodiment. The apparatus of the present embodiment is a water heater having the same system configuration as that of the water heater of FIG. 1, and in the following description, the same components as those of the water heater of FIG. And detailed description is omitted.

Referring to FIG. 4, in the water heater of the present embodiment, the controller 15 shown in FIG.
Similar to the embodiment of the above aspect, the required combustion amount calculation unit 2
2, air volume setting unit 23, fan control unit 24, valve control unit 2
5, and a stop command unit 27. Here, corresponding to the configuration of the second aspect of the present invention, the fan control unit 24 constitutes a fan control unit 28 together with the fan motor 11 and the rotation speed sensor 12, and the stop command unit 27 is an electromagnetic valve. 8
The operation stop means 27a is configured together with the fan control unit 24.

Further, the controller 14 has a configuration different from that of the embodiment of the first aspect, and the ratio of the rotation speed of the combustion fan 10 detected by the rotation speed sensor 12 to the air flow rate detected by the air flow rate sensor 13 during the hot water supply operation. First to obtain the value of
The calculation unit 39 and the value of the ratio calculated by the first calculation unit 39 at the initial stage of the hot water supply operation, for example, during prepurge, and the value of the ratio calculated by the first calculation unit 39 during the subsequent combustion of the burner 3. The second calculation unit 40 is provided which sequentially obtains the difference (change amount) and gives it to the stop command unit 27.

The first arithmetic unit 39 and the second arithmetic unit 4
The operation of the configuration except 0 is the same as that of the embodiment of the first aspect.

Next, the operation of the water heater according to this embodiment will be described mainly with respect to the operation different from that of the embodiment of the first aspect.

When the hot water supply operation is started as described above,
The first calculation unit 39 constantly obtains the value of the ratio between the rotation speed of the combustion fan 10 detected by the rotation speed sensor 12 and the air volume detected by the air volume sensor 13 until the operation ends. Then, first, at the time of prepurge at the start of the hot water supply operation, the second calculation unit 40 stores and holds the value of the ratio between the rotation speed and the detected air volume obtained by the first calculation unit 39 in a memory (not shown). deep. Specifically, referring to FIG. 5, assuming that the relationship between the number of revolutions of combustion fan 10 and the air volume at the initial stage of the hot water supply operation is the relationship shown by the solid line b in the figure, the value of the ratio is Rotational speed of combustion fan 10 at time N0
The value of the ratio (F0
/ N0, which will be described below with reference numeral H0)
Is. The value H0 of this ratio indicates the slope of the solid line b.

Next, when the burner 3 is burned as described above, the second arithmetic unit 40 causes the second arithmetic unit 40 to obtain the ratio value obtained momentarily from the first arithmetic unit 39 and the ratio value obtained during the prepurge. The difference from H0 is calculated and given to the stop command unit 27.

Specifically, assuming that the relationship between the rotational speed of the combustion fan 10 and the air volume is the relationship shown by the phantom line c in FIG. 5, the detected air volume is Nx when the rotational speed of the combustion fan 10 is Nx. Is Fcx, and the ratio value (Fcx / Nx, hereinafter,
This will be described with reference numeral H1) and the ratio value H
The difference (H0-H1) from 0 is obtained by the second arithmetic unit 40.

Here, when the exhaust port 19 is clogged, as the combustion of the burner 3 progresses, the relationship between the rotation speed of the combustion fan 10 and the air volume is shown by the solid line b in FIG. The relationship shown is the virtual line c in the figure.
The slope of the straight line showing the relationship between the rotation speed of the combustion fan 10 and the air flow rate, that is, the value of the ratio of the air flow rate to the rotation speed of the combustion fan 10 decreases relatively greatly. Therefore, when the exhaust port 19 is clogged, the difference (H0-H1) in the ratio value obtained by the second computing unit 40 becomes relatively large as the combustion of the burner 3 progresses.

Therefore, the stop command section 27 compares the difference (H0-H1) of the ratio values with a predetermined value, and if the difference exceeds the predetermined value, it is completely different from the first embodiment. Similarly, the combustion operation is stopped. At this time, the combustion operation may be stopped and the abnormal state may be notified. This also applies to the embodiment of the first aspect described above.

When the exhaust port 19 is not clogged or the degree of the clog is small, even if the air supply port 20 is clogged, the difference (H0-H1) in the ratio value is equal to the predetermined value. Therefore, in this case, the combustion operation (hot water supply operation) is performed as described in the first embodiment. That is, by the fan control unit 24,
The rotation speed of the combustion fan 10 is controlled so that the set air volume and the air volume detected by the air volume sensor 13 are controlled, and the amount of gas corresponding to the air volume is supplied to the burner 3.
The opening degree of the gas proportional valve 8 is controlled by the valve control unit 25, and the burner 3 burns with the required combustion amount.

In the present embodiment, the difference between the ratio value H0 at the beginning of operation and the ratio value H1 during combustion is determined. However, the ratio between the ratio values H0 and H1 is calculated. It is also possible to determine the clogging of the exhaust port 19 and stop the combustion operation by obtaining it and comparing it with a predetermined value.

Further, in this embodiment, the value of the ratio H
Although 0 was used as the ratio value at the time of pre-purge, the ratio value at the time of slow ignition of the burner 3 may be used, and further, the ratio value at an arbitrary initial point after the combustion of the burner 3 is started. You may use.

Further, in the present embodiment, the water heater is described as an example of the combustion device, but the second aspect of the present invention can be applied to other combustion devices such as a fan heater. Of course.

Further, in the present embodiment, the rotation speed of the combustion fan 10 is corrected according to the deviation between the set air volume and the detected air volume to match the set air volume and the detected air volume. The rotational speed of the combustion fan 10 may be corrected according to the ratio of the detected air volume to the detected air volume.

[0083]

As is apparent from the above description, according to the first aspect of the present invention, the initial detected air volume obtained by the air volume sensor corresponding to the predetermined number of revolutions of the combustion fan at the initial stage of the combustion operation, and During the subsequent combustion, when the amount of change between the detected air flow during combustion obtained by the air flow sensor corresponding to the predetermined rotation speed of the combustion fan exceeds a predetermined amount,
Since the combustion operation is stopped by the operation stopping means, the combustion operation can be automatically stopped in the case of clogging of the exhaust port which may cause exhaust leakage or incomplete combustion. When the mouth is not clogged or the degree of clogging is small, the air flow sensor detects the set air volume corresponding to the required combustion amount of the burner, not only in the normal condition but also when the air inlet is clogged to some extent. By controlling the number of revolutions of the combustion fan by the fan control means so that the air volumes match, it is possible to smoothly perform the combustion operation of the burner, and therefore, the clogging of the exhaust port can be distinguished from the clogging of the air supply port. It is possible to provide a combustion device which can be grasped and can perform an appropriate operation according to it, and which is excellent in safety and usability.

In order to control the number of revolutions of the combustion fan so that the air amount detected by the air amount sensor matches the set air amount, when the number of revolutions of the combustion fan is corrected according to the deviation between the set air amount and the detected air amount. , The difference between the set air volume and the detected air volume is used to obtain the amount of change between the initial detected air volume and the detected air volume during combustion, thereby effectively utilizing the configuration for controlling the combustion fan. You can

Further, in the initial stage of the start of the combustion operation, the initial deviation is obtained from the deviation calculation unit of the fan control means while the rotation speed and the set air volume of the combustion fan are set to the predetermined rotation speed and the predetermined set air volume, and during the subsequent combustion of the burner. In
From the deviation obtained from the deviation calculation unit at an arbitrary set air volume, the in-combustion deviation corresponding to the predetermined rotation speed and the predetermined set air volume is presumably obtained by calculation, and the difference between the initial deviation and the in-combustion deviation is calculated as described above. By determining the amount of change between the initial detected air volume and the detected air volume during combustion,
During combustion of the burner, unless the exhaust port is clogged to some extent, the set air volume and the detected air volume corresponding to the required combustion volume always match regardless of the process for obtaining the detected air volume during combustion. Therefore, it is possible to perform an accurate and smooth combustion operation.

Further, at the initial stage of starting the combustion operation, the rotation speed of the combustion fan is controlled to a predetermined rotation speed to obtain the initially detected air volume from the air volume sensor, and during the subsequent combustion of the burner, the fan control means is used. By obtaining the detected air volume during combustion at the predetermined rotation speed by calculation from the detected air volume of the air flow sensor at an arbitrary rotation speed of the controlled combustion fan, the above-described operation can be performed with a simple configuration, During combustion of the burner, unless the exhaust port is clogged to some extent, the set air volume and the detected air volume corresponding to the required combustion volume always match regardless of the process for obtaining the detected air volume during combustion. Therefore, it is possible to perform an accurate and smooth combustion operation.

Further, by controlling the rotation speed of the combustion fan to a predetermined rotation speed during the pre-purge or the slow ignition so as to obtain the initial deviation or the initial detected air volume, the normal combustion operation is performed while The initial deviation or the initially detected air volume can be easily obtained at an appropriate timing.

Further, according to the second aspect of the present invention, at the initial stage of starting the combustion operation, the value of the ratio of the air volume detected by the air volume sensor to the rotation speed of the combustion fan, which is obtained by the first arithmetic unit, and the subsequent combustion. When the amount of change between the rotational speed of the combustion fan and the value of the ratio of the detected air volume of the air volume sensor obtained by the first arithmetic unit is calculated by the second arithmetic unit, and when the amount of change exceeds a predetermined amount, By stopping the combustion operation by the operation stopping means, in the case of clogging of the exhaust port that may cause exhaust leakage or incomplete combustion, the combustion operation can be automatically stopped. If the exhaust port is not clogged or the degree of the clog is small, not only in the normal condition, but even if the air supply port is clogged to some extent, the air flow will be the set air volume corresponding to the required combustion amount of the burner. By controlling the number of revolutions of the combustion fan by the fan control unit so that the detected air volume of the sensor matches, the burner combustion operation can be performed smoothly. It is possible to provide a combustion device that can be grasped separately and can be operated appropriately according to it, and is excellent in safety and usability. The value of the ratio can be obtained very easily because the rotation speed of the combustion fan may be arbitrary, and during combustion of the burner, unless the exhaust port is clogged to some extent, it is always possible. It is possible to perform control so that the set air flow rate corresponding to the required combustion flow rate and the detected air flow rate match, so that accurate and smooth combustion operation can be performed.

Further, since the value of the ratio at the beginning of the combustion operation is obtained at the time of pre-purge or at the time of the slow ignition, the value of the ratio at the beginning of the start of the combustion operation can be easily obtained at an appropriate timing. .

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a combustion device (water heater) according to an example of a first aspect of the present invention.

FIG. 2 is a block configuration diagram of a main part of the water heater of FIG.

FIG. 3 is a block configuration diagram of a combustion device (water heater) according to another example of the first aspect of the present invention.

FIG. 4 is a block configuration diagram of a combustion device (water heater) according to an example of a second aspect of the present invention.

5 is a diagram showing the relationship between the number of rotations of the combustion fan of the water heater of FIG. 1 and the air volume.

[Explanation of symbols]

3 ... Burner, 10 ... Combustion fan, 13 ... Airflow sensor, 1
8 ... Combustion chamber, 19 ... Exhaust port, 20 ... Air supply port, 26 ... Air volume change amount calculation means, 27a ... Operation stop means, 28 ... Fan control means, 29 ... Deviation calculation means, 30 ... Storage means, 31
... Reference rotation speed setting means, 39 ... First computing means, 40 ...
Second computing means.

Claims (7)

[Claims] 1. A combustion chamber accommodating a burner, an air supply port and an exhaust port communicating with the combustion chamber, a combustion fan provided on the air supply port side to blow combustion air to the burner, An air volume sensor that detects an air volume from the combustion fan to the burner, and the combustion fan so that the detected air volume detected by the air volume sensor during combustion operation of the burner matches a set air volume for obtaining a required combustion amount of the burner. In a combustion device having a fan control means for controlling the rotation speed of
In the initial stage of starting the combustion operation of the burner, the initial detected air volume obtained by the air volume sensor corresponding to the predetermined rotation speed of the combustion fan and the predetermined rotation speed of the combustion fan during the subsequent combustion of the burner. An air volume change amount calculating means for obtaining an amount of change between the in-combustion detected air volume obtained by the air volume sensor, and an amount of change between the initial detected air volume and the in-combustion detected air volume obtained by the air volume change amount calculating means. A combustion device comprising: an operation stopping means for stopping the combustion operation when the amount exceeds a predetermined amount. 2. The fan control means stores the relationship between the air flow rate and the rotational speed of the combustion fan when the load of the combustion fan is normal as reference data in advance, and the storage means, and the reference when the burner is in a combustion operation. A reference rotation speed setting means for obtaining a reference rotation speed of the combustion fan corresponding to the set air volume based on the data, and a deviation calculation means for obtaining a deviation between the set air volume and the detected air volume obtained by the air volume sensor, The detected air volume is set by correcting the rotational speed of the combustion fan according to the deviation between the set air volume and the detected air volume while controlling the rotational speed of the combustion fan with the reference rotational speed as a reference instruction rotational speed. The combustion fan is controlled so as to match the air flow rate, and the air flow rate change amount calculation means is configured such that the reference rotation speed is equal to or higher than the reference rotation speed in the initial stage of the combustion operation of the burner. An initial deviation obtained by the deviation calculating means corresponding to a predetermined set air volume that is the number of revolutions, and an in-combustion deviation obtained by the deviation calculating means corresponding to the predetermined set air quantity during combustion of the burner. The combustion apparatus according to claim 1, wherein the difference is obtained as an amount of change between the initial detected air volume and the detected air volume during combustion. 3. The fan control means controls the number of revolutions of the combustion fan to the predetermined number of revolutions at the initial stage of starting the combustion operation, and the reference data corresponding to the predetermined number of revolutions at the time of the control. A means for giving the obtained air volume to the deviation calculation means as the predetermined set air volume,
The air volume change amount calculation means obtains a deviation output from the deviation calculation means as the initial deviation when the combustion fan is controlled to the predetermined rotation speed at the initial stage of the combustion operation, and a burner thereafter. During the combustion, when the combustion fan is controlled to the reference rotation speed corresponding to the set air volume for obtaining the required combustion amount by the fan control means, the deviation output from the deviation calculation means includes the reference rotation speed ( 3. The combustion apparatus according to claim 2, further comprising means for obtaining the deviation during combustion by multiplying a value (N0 / Nx) of a ratio between Nx) and the predetermined rotation speed (N0). 4. The fan control means includes means for controlling the number of revolutions of the combustion fan to the predetermined number of revolutions at the initial stage of starting the combustion operation, and the air volume change amount computing means
Means for obtaining as the initial detected air volume the air volume detected by the air volume sensor when the combustion fan is controlled to the predetermined number of revolutions in the initial stage of the start of the combustion operation, and the actual operation of the combustion fan during the subsequent combustion of the burner. The detected air volume during combustion is multiplied by the value (N0 / Nx) of the ratio of the rotational speed (Nx) and the predetermined rotational speed (N0) to the air volume detected by the air volume sensor at the actual rotational speed (Nx). The combustion apparatus according to claim 1, further comprising a determining unit. 5. The combustion apparatus according to claim 3, wherein the fan control means controls the number of revolutions of the combustion fan to the predetermined number of revolutions during pre-purge or during slow ignition of the burner. 6. A combustion chamber containing a burner, an air supply port and an exhaust port communicating with the combustion chamber, a combustion fan provided on the air supply port side for blowing combustion air to the burner, An air volume sensor that detects an air volume from the combustion fan to the burner, and the combustion fan so that the detected air volume detected by the air volume sensor during combustion operation of the burner matches a set air volume for obtaining a required combustion amount of the burner. In a combustion device having a fan control means for controlling the rotation speed of
First computing means for obtaining a value of a ratio of an air volume detected by the air volume sensor to a rotation speed of the combustion fan during the combustion operation, and the first operation means at an initial stage of the combustion operation of the burner.
Second calculation for obtaining the amount of change between the ratio value (H0) obtained by the calculating means of (1) and the ratio value (H1) obtained by the first calculating means during the subsequent combustion of the burner. Means and operation stopping means for stopping the combustion operation when the amount of change in the ratio value (H0, H1) obtained by the second computing means exceeds a predetermined amount. Combustion device. 7. The ratio value (H0) at the initial stage of starting the combustion operation of the burner is the ratio value at the time of prepurge or at the time of ignition of the burner.
Combustion device as described.