JPH10246433A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion apparatus which, when the combustion capacity is lowered considerably, enables avoiding degeneration of the condition of combustion caused by lack of air. SOLUTION: While fan revolution-controlling data R, S, T, U comprised of a plurality of steps each differing from the others in number of revolutions relative to the combustion capacity are preliminarily given, there is provided a fan revolution control part for lowering shift of capacity. The fan revolution control part for lowering shift of capacity monitors variation in combustion capacity and, when the combustion capacity has decreased in excess of a preliminarily set capacity-lowering variation, the revolution of the combustion fan is controlled by a shift from the fan revolution controlling data before the lowering shift of capacity to the fan revolution-controlling data in an upper step. When there is possibility that the lowering shift of the combustion capacity may cause the air volume supplied to the combustion to decrease below the volume of air adequate for satisfactory combustion, by switching to the fan revolution control data in the upper step it becomes possible to supply air at a volume adequate for satisfactory combustion so that degeneration of the condition of combustion caused by lack of air or going out of a flame can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus such as a water heater or a bath apparatus that performs combustion by using air supplied by rotating a combustion fan.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a combustion apparatus such as a water heater or a bath apparatus which can be installed indoors. 5 has a burner 1 and a combustion fan 2 for supplying and exhausting the combustion of the burner 1 in an appliance case 3, and a burner 1 is provided through an air intake port 4 provided in the appliance case 3. The indoor air (air supply) is taken in by driving the combustion fan 2, and burner combustion is performed by the air supply and the fuel gas supplied to the burner 1, and the exhaust gas generated by the combustion is supplied to the combustion fan 2. The exhaust passage 5 is driven by the
Is discharged to the outside.

[0003] The above-mentioned combustion equipment has a configuration in which the combustion capacity of the burner 1 can be varied, and the rotation of the combustion fan 2 is controlled in accordance with the combustion capacity.

[0004]

In recent years, the airtightness of buildings has been increasing, and due to the high airtightness of the building, the air pressure in the room has decreased as described below, and the building has been placed in a negative pressure state. It has been found by experiments by the applicants and others.

For example, in a state where a room is closed,
The combustion equipment installed in the room performs the combustion operation, the combustion fan 2 rotates and the ventilation fan (range hood)
6 is also rotationally driven, the indoor air is discharged to the outside by the rotational drive of the combustion fan 2 and the ventilation fan 6,
Since the amount of air entering the room is much smaller than the amount of air discharged to the outside due to the high airtightness, the air pressure in the room is reduced to a negative pressure state.

[0006] As described above, when the combustion capacity of the combustion equipment is changed in a direction in which the combustion capacity is reduced when the room is in a negative pressure state,
It has been found from experiments by the applicants that the combustion state of the combustion equipment deteriorates due to lack of air due to the negative pressure state in the room.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a fuel cell system that can be used to reduce the combustion capacity.
It is an object of the present invention to provide a combustion device that can avoid deterioration of a combustion state due to insufficient air.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the above problems. That is, in the first invention, combustion is performed by using air supplied by the rotational drive of the combustion fan, and the combustion performance can be variably controlled. The rotation speed of the combustion fan is given in accordance with the combustion performance. A plurality of stages of fan rotation control in which the number of rotations of the combustion fan with respect to the combustion performance is different from each other in a combustion device having the rotation speed of the combustion fan based on the combustion performance and the fan rotation control data. The data is provided in advance, and the change in combustion performance is monitored.If the combustion performance decreases by a predetermined amount of change in the performance decrease, the fan rotation control data is compared with the fan rotation control data before the change in the performance. Switch to high-speed fan rotation control data, and continuously burn until a predetermined standby time elapses based on the fan rotation control data. Low when fan speed side of the reduced capacity changes to switch the fan rotation control data fan rotation controller is a means of solving the problem with a configuration provided after performing rotation control of § emissions.

According to a second aspect of the invention, in addition to the configuration of the first aspect, a CO sensor for detecting the CO concentration in the exhaust gas is provided, and the CO concentration in the exhaust gas detected and output by the CO sensor is monitored. When the rotation of the combustion fan is controlled by switching to the fan rotation control data having a higher fan rotation speed than the fan rotation control data before the performance reduction by the fan rotation control unit at the time of the performance reduction, C
When the O concentration rises above a predetermined risk value, the rotation speed of the combustion fan is switched to fan rotation control data having a higher fan rotation speed, the rotation speed of the combustion fan is reduced to the fan rotation speed after the capacity change, and the reduced combustion fan A means for solving the above problem is provided by providing a high-CO generation fan rotation control unit that switches the rotation speed to the fan rotation control data on the low fan rotation speed side after continuing the rotation speed until a predetermined standby time elapses. .

According to a third aspect of the present invention, in addition to the configuration of the first aspect, a flame rod electrode for detecting a combustion flame is provided, and a flame rod current value detected and output by the flame rod electrode is monitored, and The flame rod current value is determined in advance when the rotation control of the combustion fan is performed by switching to the fan rotation control data having a larger fan rotation speed than the fan rotation control data before the performance reduction by the fan rotation control unit at the time of the decrease change. When the rotation speed rises above the upper threshold value, the rotation speed of the combustion fan is switched to the fan rotation control data with a higher rotation speed, the rotation speed of the combustion fan is reduced to the rotation speed after the capacity change, and the reduced rotation speed of the combustion fan is reduced. Current rise to switch to low fan rotation speed side fan rotation control data after continuing until a predetermined standby time elapses With a configuration in which the fan rotation control portion is provided is a means to solve the problem.

According to a fourth aspect, in addition to the configuration of the first aspect, a flame rod electrode for detecting a combustion flame and a CO sensor for detecting a CO concentration in exhaust gas are provided.
The flame rod current value detected and output by the frame rod electrode, the CO concentration in the exhaust gas detected and output by the CO sensor, and the combustion performance are monitored. When the rotation speed of the combustion fan is controlled by switching to the fan rotation control data having a higher fan rotation speed than that of the fan rotation control data, the combustion performance is lower than the predetermined combustion performance and the flame rod current value is predetermined. When the CO rotation in the exhaust gas rises above the upper threshold value, or when the CO concentration in the exhaust gas rises above a predetermined dangerous value, the rotation speed of the combustion fan is switched by switching to the fan rotation control data having a higher fan rotation speed. Reduce the number of revolutions of the fan after the capacity change, and continue the decreased number of revolutions of the combustion fan until a predetermined standby time elapses With a configuration in which the flame rod current switches after went to the low fan speed side fan rotation control data · CO concentration in combination fan rotation control portion is provided is a means to solve the problem.

A fifth invention is directed to the first, second, or third aspect.
Alternatively, instead of the fan rotation control data in which the number of revolutions of the combustion fan constituting the fourth invention is given in accordance with the combustion capacity, fan airflow control data in which the airflow of the combustion fan is given in accordance with the combustion capacity And a means for solving the above-mentioned problem with a configuration in which the amount of air corresponding to the combustion capacity is controlled by the number of revolutions of the combustion fan.

In the invention having the above configuration, for example, a plurality of stages of fan rotation control data in which the number of revolutions of the combustion fan with respect to the combustion capacity is different from each other are given in advance, and the change in the combustion capacity is changed by the fan rotation control unit at the time of the change in the capacity. The monitoring is performed, and when the combustion capacity decreases by a predetermined amount or more, the fan rotation control data is switched to the fan rotation control data higher than the fan rotation control data before the change in the performance.

If the combustion equipment is performing a combustion operation in a negative pressure chamber and a combustion capacity reduction change greater than the capacity reduction change amount is made, the combustion is continued according to the fan rotation control data before the capacity reduction change. When the rotation control of the fan is performed, the air volume of the combustion fan may become lower than the air volume for performing good combustion due to the negative pressure state, and there is a possibility that a combustion abnormal state of insufficient air may occur. By switching to the fan rotation control data in the upper stage than the fan rotation control data before the decrease, the number of rotations of the combustion fan increases and the number of rotations of the combustion fan increases as compared with performing the rotation control of the combustion fan in accordance with the fan rotation control data before the performance decrease. This prevents the amount of air supplied to the combustion from dropping significantly below the amount of air required for good combustion. To prevent the deterioration of the combustion state.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

The water heater, which is a combustion device of this embodiment, is of a type that can be installed indoors, and has a system configuration as shown in FIG.

As shown in FIG. 4, this water heater (apparatus) is provided with an air intake port 4 in an appliance case 3.
A combustion chamber 7 is provided in the appliance case 3, and a burner 1 (for example, a semi-bunsen burner that performs combustion using primary air and secondary air) is provided in the combustion chamber 7. A hot-water supply heat exchanger 8 is disposed above the burner 1, and an exhaust passage 5 in which a combustion fan 2 is incorporated is connected to a combustion chamber 7 above the burner 1.
An air supply hole 10 for taking air into the combustion chamber 7 is formed below the combustion chamber 7.

A gas nozzle 11 is provided opposite to the gas supply port of the burner 1, and a gas supply passage 12 is connected to the gas nozzle 11. The gas supply passage 12 is provided with a gas solenoid valve 13 for opening and closing the passage and a source gas solenoid valve 14, and a proportional valve 15 for variably controlling the fuel gas supply amount depending on the valve opening amount. The opening amount of the proportional valve 15 is variable according to the proportional valve driving current amount supplied to the proportional valve 15, and the variable opening amount control of the proportional valve 15 is performed by the variable control of the proportional valve driving current amount. Done.

At the inlet of the hot water supply heat exchanger 8, a water supply passage 1 is provided.
6 is connected to one end of a hot water supply heat exchanger 8, and one end of a hot water supply passage 18 is connected to the outlet side of the hot water supply heat exchanger 8.
Is connected to a water supply source through an external pipe, and the other end of the hot water supply passage 18 is guided to a predetermined hot water supply place such as a kitchen or a shower through the external pipe. Further, the hot water supply passage 16 on the inlet side of the hot water supply heat exchanger 8 and the hot water supply passage 18 on the outlet side thereof.
Is provided.

Incidentally, reference numeral 21 shown in the figure denotes CO in the exhaust gas.
Reference numeral 22 denotes a CO sensor for detecting the concentration, reference numeral 22 denotes a spark plug for igniting the burner 1, reference numeral 24 denotes a flame rod electrode for detecting a burner combustion flame, and reference numeral 25 denotes a water amount for variably controlling the flow rate of hot water in the hot water supply passage 18. Control valve, 2
Reference numeral 6 denotes a tapping thermistor for detecting tapping water temperature,
Reference numeral 27 denotes a water amount sensor that detects the flow of water through the water supply passage 16, and reference numeral 28 denotes a water input thermistor that detects the water temperature of the water supply passage 16.

The water heater is provided with a control device 30 for controlling the operation of the water heater. This control device 30
Is connected to a main body operation unit 31 installed in the appliance case 3 and a remote controller 32 installed in a place where a hot water created by the water heater is used (for example, a kitchen or a bathroom). The remote controller 32 is provided with hot water temperature setting means for setting the hot water temperature.

The operation of the appliance is controlled by the control device 30 as follows. For example, when a hot water tap (not shown) of a kitchen, a shower, or the like is opened, hot water in the hot water supply passage 16, the hot water supply heat exchanger 8, and the hot water supply passage 18 starts flowing, and the hot water supply passage 16
When the water flow sensor 27 detects the flow of water, the combustion fan 2 is driven to supply air from the air intake port 4 to the burner 1 through the air supply hole 10, the ignition plug 22 is operated, and the original gas solenoid valve 14 is operated. Then, the gas solenoid valve 13 is opened to supply the combustion gas to the burner 1 to perform the point ignition of the burner 1.

The hot water supply set temperature set in the remote controller 32, the incoming water temperature detected and output by the incoming water thermistor 28, the outgoing water temperature detected and output by the outgoing water thermistor 26, and the hot and cold water flowing through the hot water supply heat exchanger 8. Based on the flow rate and the ratio of the flow rate of hot water flowing through the bypass passage 20,
The combustion capacity for tapping the hot water at the set hot water supply temperature is determined, and the amount of fuel gas supplied to the burner 1 is controlled by the opening amount of the proportional valve 15 so as to achieve the determined combustion capacity.

Further, fan rotation control data in which the number of revolutions of the combustion fan 2 is given in accordance with the combustion capacity is given, and the number of revolutions of the combustion fan 2 corresponding to the combustion capacity is given by the fan rotation control data. And the air is supplied to the burner 1 by controlling the rotation of the combustion fan 2 so as to attain the rotation speed, and the fuel gas and the air are matched to cause the burner 1 to perform combustion. The hot water supplied from the hot water supply heat exchanger 8 is heated to produce hot water, and the produced hot water passes through the hot water supply passage 18, and the water in the bypass passage 20 is added on the way to discharge hot water to a desired tapping place.

When the use of hot water is finished and the hot water tap is closed and the water amount sensor 27 detects the stoppage of water supply, the original gas solenoid valve 14 is closed and the combustion of the burner 1 is stopped. afterwards,
A predetermined post-purge period (eg, 5 minutes),
The combustion fan 2 is continuously driven to prepare for the next hot water supply.

The water heater system shown in this embodiment is configured as described above, and this embodiment is characterized by a control configuration for appliance operation. The characteristic control structure has a structure that can prevent the deterioration of the combustion state due to the generation of the negative pressure when a negative pressure occurs in the room, and also reduces the combustion capacity when the room is in the negative pressure state. In this case, there is provided a configuration for avoiding deterioration of the combustion state due to a shortage of air due to the negative pressure state.

FIG. 1 shows a control structure characteristic of this embodiment. This water heater control device 30
Has a combustion control unit 35, a data storage unit 36, a fan rotation control data switching control unit 37, a capacity reduction change-time fan rotation control unit 38, and a high CO generation fan rotation control unit 40, as shown in FIG. It is configured.

The combustion control unit 35 is provided with a sequence program for controlling the operation of the appliance in advance.
The combustion control unit 35 fetches information of the remote controller 32 and sensor output information of various sensors, and performs the appliance operation based on the fetched information and the sequence program as described above.

The data storage section 36 is constituted by a storage device, and the data storage section 36 stores fan rotation control data. This fan rotation control data is stored in the combustion fan 2
Is the data given in correspondence with the combustion capacity (in this embodiment, the combustion capacity from the predetermined minimum combustion capacity to the maximum combustion capacity). In this embodiment, as shown in FIG. The combustion fan 2 for the combustion capacity
A plurality of stages of fan rotation control data R, S, T and U having different rotation speeds are stored in the data storage unit 36.
In this embodiment, the predetermined minimum combustion capacity is set to 0%, and the combustion capacity is increased such that the percentage value increases as the combustion capacity increases and the maximum combustion capacity becomes 100%.
Expressed as a value.

In this embodiment, as can be seen from the fan rotation control data S, T, and U shown in FIG. 2, when the fan rotation control data is switched, the fan rotation speed greatly changes at the minimum combustion capacity. At the time of the maximum combustion capacity, the fan speed is hardly changed. This is different from the general method in which the combustion is performed with a constant air-fuel ratio, and is uniquely found by the present inventors.

That is, the burner is originally a burner capable of burning with the maximum combustion capacity, and the air volume is controlled so that it does not disappear even if the fuel is reduced. In other words, the lower the combustion capacity, the more the combustion flame is extinguished if the air volume control is not performed accurately.

Therefore, in the correlation in which the air-fuel ratio is kept constant, the respective fan rotation control data are parallel, but in this embodiment, as the combustion capacity decreases, the intervals between the respective fan rotation data S, T and U become smaller. The fan rotation control data S, T, and
The interval between U is set to be narrow.

Although the fan rotation control data S, T, and U shown in FIG. 2 are gathered at one point at the maximum combustion capacity, they need not be gathered at one point at the maximum combustion capacity. The control data may be set to intersect.

The fan rotation control data is given in the form shown in FIG. 2 and, as shown in FIG. 7, the fan rotation control data of X = 0 corresponding to the fan rotation control data R of FIG. However, it may be provided in the form of parallel control lines like fan rotation control data of X = 2, X = 4.

The fan rotation control data switching controller 37
Receives the signals from the CO sensor 21 and the frame rod electrode 24, and outputs the fan rotation control data used by the combustion control unit 35 to the CO concentration detected by the CO sensor 21;
It switches and controls the fan rotation control data in accordance with the negative pressure condition of the indoor combustion environment detected by the current of the frame rod electrode 24, and has one or more of the following functions.

The first function is to switch the fan rotation control data to the fan rotation up side step by step as the CO concentration detected by the CO sensor 21 increases. An example of the operation of this function will be described with reference to the flowchart of FIG. 11. First, at step 101, it is determined whether or not the CO concentration is equal to or higher than the upper limit value. Enhanced. In this flowchart, the fan rotation control data shown in FIG. 7 is described as an example, and the number X in the flowchart corresponds to the value of X in each fan rotation control data shown in FIG.

Note that the upper limit of the CO concentration may be given as a time to reach the dangerous CO concentration when a person is exposed to the atmosphere having the CO concentration detected by the CO sensor 21, or May be given by a threshold value of a high CO concentration, or the CO concentration of blood hemoglobin is obtained when it is assumed that a person has been exposed to the atmosphere having the CO concentration detected by the CO sensor 21, and the unit time t The upper limit of the integrated value of the ratio t / T of the blood hemoglobin CO concentration and the unit time t with respect to the danger arrival time T of the blood hemoglobin CO concentration calculated each time may be given.

On the other hand, if the CO concentration is less than the upper limit value in step 101, it is determined in step 103 whether the CO concentration is equal to or less than the specified value. If the CO concentration is equal to or less than the specified value, the fan rotation control data is rotated by one step. Switch to the down side. At this time, it is determined in step 105 whether or not the fan rotation control data becomes the data of X = 0, and if it becomes the fan rotation control data of X = 0, the fan rotation control data is set to a value higher than that of the data of X = 0. X = one step above rotation
Set to 1 data.

In step 107, it is determined whether or not the value of X = 5 has been reached by switching the fan rotation control data to the one-step rotation-up side in step 102. Even if the rotation is increased, the prevention of generation of high-concentration CO gas cannot be expected.
At 108, the combustion is stopped.

When X does not reach 5 in step 107, the combustion fan is rotated at a fan speed corresponding to the combustion capacity based on the fan rotation control data whose rotation has been increased by one step in step 102. Then, the value of X is registered as the indoor negative pressure intensity. In step 111, it is determined whether or not an ON signal has been applied from the water amount sensor 27.
The subsequent operation is repeated. On the other hand, when an off signal is output from the water amount sensor 27, it is determined that the hot water tap is closed, and the combustion is stopped. And step 112
Then, the elapsed time from the stop of the combustion is measured using a timer or the like, and it is determined whether or not the time is within 10 minutes after the stop of the combustion. When the combustion operation is restarted within 10 minutes after the combustion is stopped, the negative pressure state in the room is estimated to be the same as the value of X registered in step 110, and the fan rotation control of the registered value of X is performed. The combustion operation is performed using the data.
When the time has elapsed, the fan rotation control data of X = 0, which is the fan rotation control data in the standard mode, is set to prepare for the next combustion operation.

In the flow chart shown in FIG. 11, when the pressure in the room becomes negative, a shortage of air supply occurs, and the CO concentration increases in accordance with the degree of the negative pressure in the room.
Detects an increase in the O concentration, selects and specifies fan rotation control data according to the intensity of indoor negative pressure, eliminates insufficient air supply due to negative pressure in the room, and performs good combustion operation. .

The fan rotation control data switching controller 37
The second function of the fan rotation control is to detect a frame rod current output from the frame rod electrode 24,
The function of judging the degree of negative pressure in the room based on the frame rod current and switching and setting the fan rotation control data. That is, as shown in FIG. 9, the relation data between the combustion capacity and the flame rod current is given as a threshold value to the data storage unit 36, and based on the relation data, as the degree of the negative pressure in the room increases, the fan rotation speed increases. This is a function of controlling the control data such that the control data is gradually switched to the fan rotation up side and the fan rotation control data is gradually switched to the fan rotation down side as the degree of the negative pressure decreases.

In the relational data shown in FIG. 9, a lower threshold value is given to the lower side of the flame rod current, and an upper threshold value is given to the upper side. In the example of FIG. 9, the lower threshold is given by a lower fixed threshold and a lower variable threshold, and the upper threshold is given by an upper variable threshold and an upper fixed threshold. These upper and lower fixed thresholds are given as constant values whose values do not fluctuate depending on the combustion capacity, and the upper and lower variable thresholds are varied in a direction to increase as the combustion capacity increases. These lower thresholds may be given as lower fixed thresholds or lower variable thresholds, or may be given as lower fixed thresholds depending on the category of combustion capacity. The threshold and the lower variable threshold may be selectively used. Similarly, the upper threshold value may be given by the upper fixed threshold value or the upper variable threshold value, and the upper fixed threshold value and the upper variable threshold value are selectively used according to the classification of the combustion capacity. It may be.

The fan rotation control data switching controller 37
In the operation of the second function, the frame rod current is taken in from the frame rod electrode 24, and when the frame rod current exceeds the upper threshold value, it is determined that the room is in a negative pressure state, and the fan When the rotation control data is switched to the rotation speed up side, when the frame rod current falls below the lower threshold value (exceeds below), it is determined that the negative pressure in the room has changed in the release direction and the fan The rotation control data is set to be switched to the fan rotation speed down side.

FIG. 12 is a flowchart showing the operation of the second function. That is, it is determined in step 201 whether or not the flame rod current has exceeded the upper threshold value. When the flame rod current has exceeded the upper threshold value, the fan rotation control data is increased by one step toward the fan rotation speed increasing side.
When it is determined that the frame rod current has exceeded the lower threshold value, it is determined that the negative pressure condition in the room has been released, and the fan rotation control data is switched to the one-stage fan rotation speed reduction side. Things. The up / down switching operation of the fan rotation control data is the same as the operation shown in FIG. 11, and the same operations are denoted by the same step numbers and overlapping description will be omitted.

The present inventor has verified the relationship between the degree of the negative pressure in the room and the flame rod current by experiments. 6 (a), the combustion flame is shown in FIG.
As shown in (b) of FIG.
Since the electric resistivity of the flame rod is lower than that of the external flame 45, the magnitude of the flame rod current increases, and when the negative pressure in the room is released, the shortage of the air supply is resolved, and the flame returns to the original state. It has been found that a phenomenon in which the flame rod current decreases occurs. When the flame rod current exceeds the upper threshold, a negative pressure in the room is generated and the flame rod current is reduced. When the pressure exceeds the lower threshold, it is determined that the negative pressure has been released or the degree of the negative pressure has decreased, and the fan rotation control data is switched and set according to the degree of the negative pressure in the room, and the negative pressure in the room is set. The fan speed is controlled in accordance with the degree of the pressure to ensure good combustion operation.

The fan rotation control data switching controller 37
A third function of the fan air flow control configuration according to the present invention is a function of detecting a negative pressure state and a negative pressure release state in a room based on a change amount of a frame rod current. FIG. 10 (a) shows how to detect the generation of negative pressure in the room based on the amount of increase in the frame rod current and switch and set the fan rotation control data to the fan rotation speed increasing side. The data of the value Fth1 (for example, 1.1 μA) and the reference time Tth1 (for example, 0.6 seconds) given to the rise change reference value are given. If the amount exceeds the rising change reference value Fth1 within the reference time Tth1, it is determined that the interior of the room has been reduced to a negative pressure due to, for example, activation of a range hood or a ventilation fan during the combustion operation, and the fan rotation. The control data X is set to the rotation speed increasing side ((X + 1) side)
Switch to and set.

FIG. 10 (b) shows a function of detecting the release of negative pressure in the room based on the amount of decrease in the frame rod current. The data storage unit 36 stores a reference value Fth2 for the decrease in the frame rod current and the reference value Fth2. A reference time Tth2 given to the descending change reference value is given, and the fan rotation control data switching control unit 37 sets the descending change reference value Fth2 within the time of the judgment time Tth2 when the amount of the descending change of the frame rod current is within the judgment time Tth2. If it exceeds, it is determined that the negative pressure condition in the room has been released (or changed in the negative pressure decreasing direction), and the fan rotation control data X is switched to the fan rotation speed down side ((X-1) side).

FIG. 8 shows a function of detecting a sudden negative pressure change in the room based on the amount of sudden decrease in the flame rod current and switching and setting the fan rotation control data in a direction to increase the fan rotation speed. In this function, the data storage unit 36 stores the reference value Fth0 for the downward change of the frame rod current.
(For example, 0.7 μA) and data for a minute set time ΔTth (for example, 0.1 second) having a time width narrower than the determination time Tth2 shown in FIG. When the flame rod current falls below the falling change reference value Fth0 within the minute set time ΔTth, the unit 37 performs the combustion operation with the range hood activated and the indoor hood open, for example. At this time, it is determined that the flame rod current suddenly changes because the door is closed suddenly, the interior of the room suddenly becomes a negative pressure, and the combustion flame starts to extinguish (the flame becomes extremely small). In this case, in order to solve the shortage of air supply due to the sudden generation of the negative pressure, the fan rotation control data X is changed to the fan rotation speed increasing side ((X + 1)
Side).

When the fan rotation control data switching control section 37 switches the fan rotation control data by any function, the combustion control section 35 uses the switched fan rotation control data to set the combustion fan 2. The rotation control of is performed.

The fan rotation control data switching controller 37
Is provided with one or more functions of the plurality of functions to set fan rotation control data according to the indoor negative pressure condition. In particular, the combustion performance is, for example, a specified value of a control range (for example, In the low combustion capacity range of less than 30%), the combustion performance is more affected by the negative pressure in the room.
In this low combustion capacity range, the first function (basic function) based on the CO detection signal of the CO sensor and the one or more functions (additional functions) based on the flame rod current are combined, and the indoor By using both the setting of the fan rotation control data based on the detection of the negative pressure level and the setting of the switching of the fan rotation control data based on the detection of the room negative pressure level based on the frame rod current, it is possible to adjust the degree of the negative pressure in the room. Accurate fan rotation control becomes possible.

That is, in the region where the combustion capacity is low, CO that is released due to deterioration of combustion due to insufficient
If the sensor 21 collects and detects deterioration of combustion, CO 2
It takes a long time from the occurrence of the error to the detection by the CO sensor 21, and there is a possibility that a fire may occur during this time. In this regard,
The flame rod current reacts instantaneously to the deterioration of combustion, and detects the deterioration of combustion quickly by the change of the flame rod current.
Misfire can be prevented by quickly controlling the air flow in the combustion improvement direction.

On the other hand, the flame rod electrode has a range based on the relationship between the mounting position at which the deterioration of combustion can be detected with high sensitivity and the combustion capacity.
Although the detection sensitivity of the deterioration of combustion is reduced, in a high combustion capacity range (for example, a range of the combustion capacity X to 100% shown in FIG. 9), the deterioration of combustion can be properly detected by the CO sensor. A combination of the negative pressure detection based on the flame rod current in the capacity range (for example, the range of the combustion capacity 0 to X% shown in FIG. 9) and the negative pressure detection based on the CO concentration detection by the CO sensor in the high combustion capacity range. Accordingly, the negative pressure condition of the indoor combustion environment can be accurately detected in the entire range of the combustion capacity, and more accurate fan rotation control according to the degree of the negative pressure in the room can be performed.

In the embodiment shown in FIGS. 11 and 12, when the fan rotation control data is sequentially increased to the rotation speed increasing side, X = 0, X = 1, X = 2, X = 3.
X is sequentially increased by one, such as X = 4, and when the fan rotation control data is reduced to the rotation speed reduction side, X is increased.
= 4, X = 3, X = 2, and X = 1, the X is sequentially decreased by one. However, the order of ascending and descending of the fan rotation control data is not necessarily limited to this. For example, When increasing the fan rotation control data,
X = 0, X = 2, X = 3, X = 4 may be raised in a procedure such as:

By the way, as described above, the air pressure in the room in which the combustion operation of the water heater is performed in the closed room and the combustion fan 2 is driven to rotate and the ventilation fan 6 is also driven to rotate is:
Due to the high airtightness of the room, the air pressure is lower than the atmospheric pressure outside the room.
The air pressure PLO shown in FIG. In the case where the combustion capacity of the water heater is reduced due to the variable reduction of the set hot water supply temperature or the like when the room is in the negative pressure state, the rotation speed of the combustion fan 2 is controlled to decrease in accordance with the change in the reduction of the combustion capacity. As the amount of air discharged from the room to the outside decreases, the air pressure in the room increases, for example, the air pressure in the room increases from PLO to Phi as shown by a curve P in FIG. The negative pressure state is alleviated.

When the negative pressure in the chamber is alleviated, the following negative pressure delay phenomenon occurs. The negative pressure delay is defined as a difference between the rotational speed of the combustion fan 2 before the performance decrease and the combustion fan 2 after the performance decrease.
The time required to reach the rotation speed of the combustion fan 2 does not take, for example, about 1 second, whereas the time Δt required for the indoor air pressure to increase from PLO to Phi due to the decrease in the rotation speed of the combustion fan 2 is, for example, , It takes about 10 seconds,
The change in the increase in the air pressure in the room due to the change in the decrease in the combustion capacity under the negative pressure state is a phenomenon that does not follow the change in the decrease in the rotational speed of the combustion fan 2. It has been found from experiments and the like by the present inventors that a problem arises in that the problem is caused by insufficient air.

When the room is in a negative pressure state, the flow of air in the direction from the outside to the room through the exhaust passage 5 is reduced by the decrease of the indoor air pressure with respect to the outdoor air pressure (the magnitude of the negative pressure state). ), The negative pressure state in the room is almost equal to the state before the change in the capacity due to the negative pressure delay, although the rotation speed of the combustion fan 2 after the change in the capacity decreases due to the change in the capacity. In the case of, the amount of air flowing backward through the exhaust passage 5 is almost the same as before the change in the capacity.

On the other hand, the rotational speed of the combustion fan 2 after the change in capacity is reduced is assumed to be a good value, assuming the backflow air volume in a state where the negative pressure in the room is reduced due to the change in capacity. Since the rotation speed is for supplying the air flow for performing the combustion, the air flow of the combustion fan 2 is smaller than the air flow for performing the good combustion due to the backflow having the magnitude due to the negative pressure delay. I do. For this reason, the amount of air supplied to the burner 1 is much smaller than the amount of air for performing good combustion, and the combustion state deteriorates due to insufficient air, or the combustion flame burns out due to excessive insufficient air. Occurs.

Therefore, this embodiment proposes a means for avoiding the deterioration of the combustion capacity due to the shortage of air and the occurrence of the extinguishing of the combustion flame when the above-mentioned change in the combustion capacity is changed.

At the time of the change in the capacity reduction, the fan rotation control section 38 fetches the information of the combustion capacity from the combustion control section 35 every moment, and stores the fetched combustion capacity in a built-in memory (not shown) in correspondence with the time. At the same time, a change in the combustion capacity is monitored as follows based on the information on the captured combustion capacity.

For example, the fan rotation control unit 38 at the time of the change in the performance decrease fetches the current combustion performance from the combustion control unit 35, and fetches the current combustion performance before a predetermined set time (for example, 2.6 seconds before) and stores it in the internal memory. The stored combustion capacity before the set time is read out, and the current combustion capacity is compared with the combustion capacity before the set time to determine a change amount of the current combustion capacity with respect to the combustion capacity before the set time.

Then, at the time of the performance decrease change, the fan rotation control unit 38 compares the obtained change amount of the combustion performance with a predetermined performance decrease amount ΔE (for example, 10%). The above-mentioned capacity decrease change amount ΔE is a combustion capacity decrease change amount for judging whether or not there is a possibility that the combustion state may be deteriorated due to the negative pressure delay when the combustion capacity decrease change is performed. It is obtained by calculation or the like.

When the performance is changed, the fan rotation control unit 38
When it is determined based on the change in the combustion capacity that the combustion capacity has decreased by the capacity reduction change ΔE or more, if the rotation speed of the combustion fan 2 is reduced according to the fan rotation control data before the capacity change, the room will In the case of the negative pressure state, it is determined that there is a risk that the negative pressure delay may cause a problem such that the combustion state is deteriorated due to insufficient air or that the combustion flame is extinguished due to excessive insufficient air. The rotation control data is switched to the fan rotation control data at a higher stage than the fan rotation control data before the performance reduction change, and a control data up signal for performing the rotation control of the combustion fan 2 is output to the combustion control unit 35.

When the combustion control unit 35 receives the control data up signal from the above-mentioned performance reduction change fan rotation control unit 38, the combustion control unit 35 converts the fan rotation control data into the predetermined upper fan rotation control data (for example, before the performance reduction change). (Fan rotation control data one step higher than fan rotation control data)
And the rotation of the combustion fan 2 is controlled.

More specifically, for example, when the rotation control of the combustion fan 2 is being performed according to the fan rotation control data S shown in FIG. In accordance with the change in the set hot water supply temperature, the combustion capacity is changed from the combustion capacity α to the combustion capacity β so as to be reduced by the above-mentioned capacity reduction change amount ΔE or more, and a control data up signal is output from the fan rotation control unit 38 at the time of the capacity reduction change. In this case, the combustion control unit 35 receives the control data up signal and switches from the fan rotation control data S to the fan rotation control data T in the upper stage by one step to control the rotation of the combustion fan 2.

By the switching of the fan rotation control data, the combustion fan 2 is increased from the rotation speed at the point A of the fan rotation control data S shown in FIG. From this point B, according to the fan rotation control data T, the rotational speed of the combustion fan 2 corresponding to the combustion capability β after the capacity change is reduced to the rotational speed of the point C which is the rotational speed.

The above-mentioned capacity reduction change-time fan rotation control section 38
Has a built-in timer (not shown). After outputting the control data up signal, the rotation speed of the combustion fan 2 reaches the rotation speed after the capacity change based on the operation information of the combustion control unit 35. Is detected, the built-in timer is driven, the measured time of the timer is compared with a predetermined standby time (for example, 10 seconds), and it is determined whether the measured time of the timer has reached the standby time. I do.

The standby time is a time obtained by adding a margin time to a time Δt from when the rotational speed of the combustion fan 2 is reduced and changed until the negative pressure delay is almost eliminated, and is a data obtained in advance by experiments, calculations, and the like. It is stored in the storage unit 36.

When it is determined that the time measured by the timer has reached the standby time, the fan rotation control unit 38 at the time of the change in performance decreases switches to the lower fan rotation control data because the negative pressure delay has been eliminated. It is determined that the problem of deterioration of the combustion state caused by the negative pressure delay can be avoided even if the rotation control of the combustion fan 2 is performed, and a control data down signal is output to the combustion control unit 35.

When the combustion control unit 35 receives the control data down signal from the capacity reduction change fan rotation control unit 38, the combustion control unit 35 determines predetermined lower fan control data (for example, the fan rotation control data S before the performance reduction change). And the rotation of the combustion fan 2 is controlled.

Specifically, for example, after the point C of the fan rotation control data T in FIG. 2, which is the number of revolutions of the combustion fan 2 after the above-mentioned capacity reduction change, is continuously performed until the standby time elapses, Switching from the fan rotation control data T to the fan rotation control data S, the combustion fan 2 is reduced from the rotation speed at the point C of the fan rotation control data T to the rotation speed at the point D of the fan rotation control data S.

As described above, when there is a possibility that the combustion state may be deteriorated due to the lack of air due to the negative pressure delay at the time of the change in the performance, the fan rotation control data is stored in the upper stage than the fan rotation control data before the change in the performance. To reduce the number of revolutions of the combustion fan 2 to the number of revolutions after the change in the capacity reduction by switching to the fan rotation control data of the combustion fan 2. The number of rotations of the fan is large, and the amount of air supplied to the burner 1 can be suppressed from being significantly reduced from the amount of air required for performing good combustion, and the negative pressure at the time of the change in capacity reduction can be suppressed. It is possible to prevent the deterioration of the combustion state due to the shortage of air due to the delay.

In addition, the rotation speed based on the fan rotation control data in the upper stage is maintained until the set standby time elapses after the rotation speed has been reduced to the rotation speed after the change in the performance reduction, that is, until the negative pressure delay is eliminated. Therefore, the effect of preventing the deterioration of the combustion state due to the lack of air due to the negative pressure delay can be continued until the negative pressure delay is eliminated.

By the way, when the negative pressure delay occurs, the air volume of the combustion fan 2 decreases as the decrease in the combustion capacity increases even if the rotation speed of the combustion fan 2 is equal. For this reason, although the rotation of the combustion fan 2 is controlled by switching to the upper-stage fan rotation control data by the fan rotation control unit 38 at the time of the performance reduction change, the combustion fan 2 2, the amount of air supplied to the burner 1 becomes smaller than the amount of air supplied to perform good combustion, and the amount of air supplied to the burner 1 becomes smaller than the amount of air supplied to perform good combustion. There are cases.

Therefore, in this embodiment, the fan rotation control unit 40 is provided at the time of high CO generation, so that the combustion performance is reduced by the capacity reduction change amount ΔE or more and the fan rotation control data in the upper stage than the fan rotation control data before the performance reduction is changed. When the rotation of the combustion fan 2 is controlled by switching to the data, the high C
When the O-occurrence fan rotation control unit 40 detects a combustion state of insufficient air, the fan rotation control data is further switched to the upper fan rotation control data to control the rotation of the combustion fan 2. . The present inventors have paid attention to the fact that the CO concentration in the exhaust gas increases when the combustion state deteriorates due to the lack of air, and detect the deterioration of the combustion state due to the lack of air by detecting the increase in the CO concentration in the exhaust gas. .

When high CO is generated, the fan rotation control unit 40
The sensor output of the O sensor 21 is detected as the CO concentration in the exhaust gas, and based on the operation information taken from the combustion control unit 35 and the fan rotation control unit 38 at the time of the performance decrease change, the fan rotation before the performance decrease is changed by the performance decrease. While detecting that the rotation control of the combustion fan 2 is being performed by switching to the fan rotation control data higher than the control data, C in the exhaust gas detected and output by the CO sensor 21 is detected.
O concentration is a predetermined dangerous value (for example, 2000 ppm)
When it is determined that the above is the case, the control data up signal at the time of high CO generation is output to the combustion control unit 35.

The above-mentioned danger value is a CO concentration in the exhaust gas for judging whether or not the combustion state has deteriorated due to a shortage of air.
Is stored in

When the combustion control unit 35 receives the high CO generation control data up signal from the high CO generation fan rotation control unit 40, the combustion control unit 35 changes the capacity reduction change fan rotation control unit 38.
Although the rotation of the combustion fan 2 was controlled by switching to the fan rotation control data higher than the fan rotation control data before the capacity change, the combustion state deteriorated due to insufficient air, so the deterioration of the combustion state due to insufficient air was improved. In order to increase the fan air volume by switching to the upper fan rotation control data and controlling the rotation of the combustion fan 2,
It is determined that it is necessary to increase the amount of air supplied to the fan, and the rotation control of the combustion fan 2 is performed by switching the fan rotation control data to the further upper fan rotation control data.

For example, when the performance is changed, the fan rotation control data S is switched to the fan rotation control data T, and the rotation speed of the combustion fan 2 is reduced in accordance with the fan rotation control data T (for example, the point E in FIG. 2). If the CO concentration in the exhaust gas becomes equal to or higher than the dangerous value at the time when the number of rotations decreases to the rotation speed of the high CO generation, the high CO generation control data up signal output from the high CO generation fan rotation control unit 40 is output. Is received by the combustion control unit 35 and further switched to the fan rotation control data U in the upper stage, that is, the combustion fan 2
After the rotation speed of the combustion fan 2 is increased to the rotation speed of the point F, the rotation speed of the combustion fan 2 is reduced to a point G which is the rotation speed after the change in the performance is reduced according to the fan rotation control data U.

The high-CO generation fan rotation control unit 40 has a built-in timer. Based on the operation information fetched from the combustion control unit 35, the rotation speed of the combustion fan 2 reaches the rotation speed after the capacity change. When the timer is detected, the timer is started to drive, and the measured time of the timer is compared with a predetermined standby time Tco (for example, 10 seconds), and it is determined that the measured time of the timer has reached the standby time Tco. Sometimes high CO
Outputs a control data down signal when an error occurs.

The standby time Tco is a time obtained by adding a margin time to a time required for substantially eliminating the negative pressure delay, and is obtained in advance by experiments or calculations and stored in the data storage unit 36.

When the combustion control unit 35 receives the high-CO generation control data down signal from the high-CO generation fan rotation control unit 40, the combustion control unit 35 removes the negative pressure delay, and converts the fan rotation control data to the lower fan rotation control data. It is determined that the fan rotation control data may be switched to the control data, and the fan rotation control data is changed to the lower fan rotation control data (for example, the fan rotation control data T one step below the fan rotation control data U or the fan rotation control The data is switched to data S), and the rotation of the combustion fan 2 is controlled.

When the high CO generation fan rotation control unit 40 outputs the high CO generation control data up signal, it simultaneously outputs a control data down signal from the capacity reduction change fan rotation control unit 38. A cancellation signal for canceling the operation is output to the performance reduction change fan rotation control unit 38, and the output of the control data down signal from the performance reduction change fan rotation control unit 38 is canceled.

According to this embodiment, when the combustion capacity is changed, if the combustion state is likely to be deteriorated due to a shortage of air due to a negative pressure delay caused by the change in the capacity,
Since the rotation control of the combustion fan 2 is performed by switching to the fan rotation control data higher than the fan rotation control data before the capacity change, the combustion fan is controlled more than the rotation control of the combustion fan 2 according to the fan rotation control data before the capacity change. 2, it is possible to prevent the amount of air supplied to the burner 1 from being significantly reduced from the amount of air supplied to the burner 1 for performing good combustion. The problem of extinguishing of the combustion flame due to excessive shortage of air can be avoided.

In this embodiment, since the high-CO generation fan rotation control section 40 is provided, the rotation of the combustion fan 2 is controlled by switching to the upper-stage fan rotation control data by the capacity reduction change fan rotation control section 38. I did
If the amount of air supplied to the burner 1 is smaller than the amount of air for performing a good combustion state and the combustion state is deteriorated due to insufficient air, the deterioration of the combustion state due to the insufficient air is determined by the CO in the exhaust gas. Detected by the increase in concentration,
The O-occurrence fan rotation control unit 40 can switch to the fan rotation control data in the upper stage.

As described above, since it is possible to switch to the fan rotation control data in the upper stage, the air volume of the combustion fan 2 can be increased to increase the amount of air supplied to the burner 1, and the air-deficient combustion state can be reduced. Deterioration can be improved, and the problem of extinguishing of the combustion flame due to excessive air shortage can be reliably avoided.

Further, even after the negative pressure delay has been eliminated, the rotation of the combustion fan 2 is performed at the rotation speed of the upper fan rotation control data so that a favorable combustion state can be performed when the negative pressure delay occurs. When the driving is continued, the air volume of the combustion fan 2 becomes larger than the air volume at which good combustion can be performed, and the amount of air supplied to the burner 1 increases more than the air volume at which good combustion is performed. The combustion state may deteriorate.

On the other hand, in the above-mentioned embodiment, the fan rotation control unit 38 at the time of the change in performance and the fan rotation control unit 40 at the time of the occurrence of the high CO decrease to the rotation speed after the change in the performance decrease and are determined in advance. Since the switching to the lower fan rotation control data is performed after the standby time is continuously performed, the rotation of the combustion fan 2 is controlled by switching to the lower fan rotation control data after the negative pressure delay has been eliminated, so that the above-mentioned excessive air is caused. The deterioration of the combustion state can be avoided.

Note that the present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, in the above embodiment, the capacity reduction change-time fan rotation control unit 38 takes in the information of the combustion capacity from the combustion control unit 35, but, for example, the opening of the proportional valve 15 variably controlled according to the combustion capacity. The valve amount (that is, the proportional valve drive current) may be detected as the combustion capacity.

In the above-described embodiment, when the combustion capacity is reduced by the predetermined capacity reduction change amount ΔE or more, regardless of whether or not a negative pressure state is present, the fan rotation control unit 38 at the time of the capacity reduction change sets the combustion Although the fan rotation control data was switched to the fan rotation control data in the upper stage than the fan rotation control data before the performance reduction, the negative pressure delay occurs when the performance reduction is changed because the room is in the negative pressure state. When the means for detecting the decrease in the capacity is provided, the fan rotation control unit 38 at the time of the change in the capacity lowering is set to the upper stage only when the combustion capacity is reduced by the set capacity lowering change amount ΔE or more when the room is in the negative pressure state. The control may be switched to fan rotation control data.

When the combustion capacity is reduced by the capacity reduction variation ΔE or more and switched to the upper fan rotation control data when the room is not in the negative pressure state, the rotation of the combustion fan 2 is changed according to the upper fan rotation control data. Since the control is performed for a very short time of about 10 seconds, the deterioration of the combustion state due to excessive air as described above can be substantially avoided.

Further, in the above embodiment, when switching to the fan rotation control data at the upper stage than the fan rotation control data before the performance change, the fan rotation control unit 38 at the time of the performance reduction changes the size of the performance reduction change amount. Regardless, the fan rotation control data is switched to the fan rotation control data one stage higher than the fan rotation control data before the capacity change. For example, when the capacity reduction change amount is within the range of 10% or more and less than 35%. Is 1 more than the fan rotation control data before the capacity change.
Switching to the fan rotation control data at the upper stage, if the change in capacity decrease is in the range of 35% or more and less than 50%, the degree of deterioration of the combustion state due to insufficient air is large because the change in capacity decrease is large. It is necessary to increase the rotation speed of the combustion fan 2 in order to avoid the deterioration of the combustion state due to the shortage of air, so that the fan rotation speed is two stages higher than the fan rotation control data before the capacity change. When switching to the fan rotation control data, such as switching to the control data, the fan rotation control unit 38 selects the fan rotation control data corresponding to the magnitude of the change in the power reduction when switching to the upper fan rotation control data. The control may be switched to fan rotation control data.

As described above, by selecting and switching the fan rotation control data according to the magnitude of the change in the performance decrease, the fan rotation control unit 38 at the time of the change in the performance decreases the degree of the combustion deterioration state caused by the negative pressure delay. It is possible to switch to the fan rotation control data corresponding to the above. From this, when the performance is changed, the combustion state is not deteriorated due to the shortage of air even though switching to the upper fan rotation control data is performed. In such a case, the high CO generation fan rotation control unit 40 is used. May be omitted.

Further, in the above-described embodiment, the fan rotation control unit 38 at the time of the change in the capacity and the fan rotation control unit 40 at the time of the high CO generation indicate that the number of rotations has decreased to the speed after the change of the capacity according to the switched fan rotation control data. Combustion control unit 35
For example, when the combustion fan 2 is provided with a rotation speed detection sensor for detecting the rotation speed, the rotation speed of the combustion fan 2 detected by the rotation speed detection sensor is detected. May be detected on the basis of

Further, in the above-described embodiment, the fan rotation control data is given in the form of graph data. However, the fan rotation control data may be given in a data format other than the graph data such as table data or arithmetic expression data.

Further, in the above-described embodiment, the standby time for determining the timing of switching to the lower fan rotation control data is constant, but the time required for eliminating the negative pressure delay as the capacity reduction change amount increases. Since the length of time becomes longer, the standby time may be lengthened continuously or stepwise as the capacity change amount increases.

Further, in the above embodiment, the rotation speed of the combustion fan 2 is controlled based on the fan rotation control data in which the rotation speed of the combustion fan 2 is given in accordance with the combustion capacity. As shown in FIG. 2, instead of the fan rotation control data, the air flow of the combustion fan 2 is controlled by using the fan air volume control data given in correspondence with the combustion capacity. Is also good.

Further, in place of the high-CO generation fan rotation control section 40 shown in the above embodiment, a current rise fan rotation control section 42 shown by a dotted line in FIG. 1 may be provided. Focusing on the fact that the deterioration of the combustion can be detected based on the flame rod current as described above, the fan rotation control unit 42 at the time of current rise switches to the fine rotation control data at the upper stage by the fan rotation control unit 38 at the time of the change in capacity reduction and performs combustion. When the deterioration of the combustion is detected based on the flame rod current while the rotation control of the fan 2 is being performed, the data is further switched to the fan rotation control data in the upper stage to avoid the deterioration of the combustion state due to the negative pressure delay. Things. less than,
An example of the control operation of the above-described current rise fan rotation control unit 42 will be described.

The current rising fan rotation control unit 42 detects the flame rod current detected and output from the flame rod electrode 24, and based on the operation information taken from the combustion control unit 35 and the capacity reduction changing fan rotation control unit 38, While detecting that the rotation control of the combustion fan 2 is being performed by switching to the fan rotation control data in the upper stage from the fan rotation control data before the performance reduction by the performance reduction change,
When it is determined that the flame rod current has risen above the upper threshold value shown in FIG. 9, a control data up signal at the time of current rise is output to the combustion control unit 35.

When the combustion control unit 35 receives the current rise control data up signal from the current rise fan rotation control unit 42, the combustion control unit 35 switches to the fan rotation control data of the higher fan rotation speed to rotate the combustion fan 2. Perform control.

The current-increase fan rotation control unit 42 has a built-in timer (not shown). Based on the operation information fetched from the combustion control unit 35, the rotation speed of the combustion fan 2 is changed after the capacity is changed. When it is detected that the number has reached the count, the timer is driven, the measured time of the timer is compared with a predetermined standby time Tst (for example, 10 seconds), and the measured time of the timer reaches the standby time Tst. When it is determined that the current has risen, a control data down signal at the time of current rise is output.

When the combustion control unit 35 receives the current rise control data down signal from the current rise fan rotation control unit 42, the combustion control unit 35 switches the fan rotation control data to the low rotation speed side fan rotation control data to switch the combustion fan 2 The rotation control of is performed.

By providing the above-mentioned fan rotation control unit 42 at the time of current rise, the fan rotation control unit 3
In the case where the combustion state is deteriorated due to a shortage of air while the rotation control of the combustion fan 2 is being performed by switching to the upper-stage fan rotation control data by 8, the deterioration of the combustion state is determined based on the flame rod current. Since the detection can be performed and the data can be switched to the fan rotation control data in the upper stage, the deterioration of the combustion state due to the lack of air due to the negative pressure delay can be reliably prevented.

Further, instead of the high-CO generation fan rotation control unit 40 shown in the above embodiment, a frame rod current value / CO concentration combined fan rotation control unit 44 shown by a chain line in FIG. 1 may be provided.

The frame rod current value / CO concentration combined fan rotation control unit 44 is, for example,
In addition to capturing the flame rod current detected and output from the combustion control unit 35 and the information on the combustion performance, the sensor output detected and output by the CO sensor 21 is detected as the CO concentration in the exhaust gas, and the combustion control unit 35 Based on the operation information fetched from the fan rotation control unit 38 at the time of the performance reduction, the rotation of the combustion fan 2 is controlled by switching to the fan rotation control data higher than the fan rotation control data before the performance reduction by the performance reduction. It is determined that the combustion performance is below the predetermined combustion performance (for example, combustion performance of 30%) while the flame rod current has risen above the upper threshold shown in FIG. When it is determined, or when it is determined that the CO concentration in the exhaust gas has increased to a predetermined dangerous value (for example, 2000 ppm) or more. And outputs a current rise and high CO occurrence control data up signal to the combustion controller 35.

When the combustion control unit 35 receives the control data up signal at the time of current increase / high CO generation from the flame rod current value / CO concentration combined fan rotation control unit 44, the combustion control unit 35 controls the fan rotation on the side with a higher fan rotation speed. The rotation of the combustion fan 2 is controlled by switching to the data.

Further, the fan rotation control unit 44 for combined use of the flame rod current value and the CO concentration has a built-in timer (not shown), and the rotation speed of the combustion fan 2 is determined based on the operation information fetched from the combustion control unit 35. When it is detected that the number of revolutions after the capacity change has been reached, the timer is driven, and the measured time of the timer is set to a predetermined standby time Tst (for example, 10 seconds).
Seconds), the measured time of the timer is the standby time Tst described above.
, A control data down signal is output when a current rise / high CO occurs.

When the combustion control unit 35 receives the current rise / high CO generation control data down signal from the flame rod current value / CO concentration combined fan rotation control unit 44, the combustion control unit 35 converts the fan rotation control data to the low rotation speed side fan. The rotation of the combustion fan 2 is controlled by switching to the rotation control data.

As described above, the flame rod current has a current range in which deterioration of combustion can be detected with high sensitivity.
In a region out of this current range, combustion deterioration can be detected with high sensitivity based on the CO concentration.Therefore, by using the combustion state deterioration detection based on the flame rod current and the combustion state deterioration detection based on the CO concentration in the exhaust gas together,
The deterioration of the combustion state can be detected with high sensitivity over the entire range of the combustion capacity.

By providing the above-described fan rotation control unit 44 for combined use of the flame rod current value and the CO concentration, the rotation of the combustion fan 2 is controlled by switching to the upper-stage fan rotation control data by the fan rotation control unit 38 when the performance decreases. If the combustion state has deteriorated due to lack of air during the operation, the deterioration of the combustion state can be detected based on the flame rod current, and it is possible to switch to the fan rotation control data in the upper stage, The deterioration of the combustion state due to the lack of air due to the negative pressure delay can be reliably prevented.

Further, in this embodiment, the burner 1 is constituted by a burner such as semi-bunsen which burns by using primary air and secondary air. Since the rich burner receives the air from the light burner and burns it, the combustion of the rich burner approximates the combustion form of the semi-bunsen burner. Accordingly, the flame rod current can be changed within a relatively wide range between the upper limit and the lower limit, so that the combustion improvement operation described in the above embodiment can be applied to a combustion device having a light and dark burner.

Further, the above embodiment has been described by taking the water heater shown in FIG. 4 as an example. However, the combustion is performed by using the air supplied by the rotational drive of the combustion fan, and the combustion capacity can be variably controlled. The present invention can be applied to any combustion device that controls the rotation of a combustion fan in accordance with the combustion capacity. For example, the present invention can be applied to a combustion device other than the water heater shown in FIG. 4 such as an oil fan heater. It can be applied, and the same effect as the above embodiment can be obtained.

[0113]

According to the present invention, there is provided a fan rotation control unit at the time of a change in the performance, and a plurality of stages of fan rotation control data having different rotation speeds for the combustion performance or fan air flow rates for the combustion performance are mutually different. Since different plural stages of fan air volume control data are given, if the combustion capacity is reduced by a predetermined capacity reduction change amount or more,
The fan rotation control unit at the time of the change in performance reduction can switch the fan rotation control data or the fan air volume control data to control data higher than the control data before the change in performance reduction.

As a result, when there is a possibility that a negative pressure delay occurs due to a change in the capacity reduction and the combustion state is deteriorated due to a shortage of air while the room in which the combustion equipment is installed is in a negative pressure state, the combustion capacity is reduced. As a result, the air volume of the combustion fan can be suppressed from decreasing below the air volume for performing good combustion, and the air volume for performing good combustion can be supplied to the combustion. Deterioration and extinguishing of the combustion flame due to excessive air shortage can be avoided.

If the fan rotation control unit for high CO generation, the fan rotation control unit for current rise, and the fan rotation control unit for combined use of the flame rod current value and CO concentration are provided, the fan rotation control unit for changing the above-mentioned capacity reduction is used. When the control unit switches to the upper combustion capacity and controls the rotation of the combustion fan, the deterioration of the combustion state is detected based on the CO concentration in the exhaust gas detected by the CO sensor and the flame rod current value. In this case, the high-CO generation fan rotation control unit, the current rise fan rotation control unit, and the frame rod current value / CO concentration combined fan rotation control unit
Furthermore, since the rotation control of the combustion fan is performed by switching to the upper fan rotation control data or the fan air volume control data, when the capacity reduction is changed, the combustion fan is switched to the upper control data by the above-mentioned capacity reduction change fan rotation control unit. Deterioration of the combustion state due to lack of air occurs after the rotation control was performed, the deterioration of the combustion state due to the lack of air is detected by the CO concentration in the exhaust gas and the flame rod current. By switching the control data to control the rotation of the combustion fan, the air volume of the combustion fan can be increased, and the amount of air supplied to the combustion can be increased to improve the deterioration of the combustion state.

The control data in the upper stage is obtained by the fan rotation control unit when the capacity is changed, the fan rotation control unit when a high CO is generated, the fan rotation control unit when the current is increased, and the fan rotation control unit that uses both the frame rod current value and the CO concentration. After switching, the rotation speed of the combustion fan 2 is reduced, and the reduced rotation speed is continuously performed until a predetermined standby time elapses. Then, the control data is switched to the lower control data. Since the rotation control of the combustion fan is continued according to the upper control data, it is possible to avoid the problem that the combustion state is deteriorated due to excessive air.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing an example of fan rotation control data.

FIG. 3 is a graph showing an example of a change in indoor air pressure when the combustion capacity is changed to decrease when the indoor pressure is negative.

FIG. 4 is a model diagram showing an example of a water heater.

FIG. 5 is an explanatory diagram showing a mechanism in which a room enters a negative pressure state.

FIG. 6 is an explanatory view showing an example of a combustion flame in a good combustion state and a combustion flame in a combustion deterioration state due to a shortage of air.

FIG. 7 is an explanatory diagram showing another example of the fan rotation control data.

FIG. 8 is an explanatory diagram of an example of detecting a sudden generation of a negative pressure in a room based on a sudden drop change amount of a frame rod current.

FIG. 9 is an explanatory diagram of a setting example of an upper threshold value and a lower threshold value of a frame rod current.

FIG. 10 is an explanatory diagram of an example in which generation of a negative pressure in a room and release of the negative pressure are detected based on a change amount of a frame rod current.

FIG. 11 is a flowchart illustrating an operation example of detecting a negative pressure state in a room based on CO concentration and performing fan rotation control.

FIG. 12 is a flowchart of an operation example of detecting a negative pressure state in a room by a frame rod current and performing fan rotation control.

[Explanation of symbols]

2 Combustion fan 21 CO sensor 38 Fan rotation control unit at the time of capacity reduction change 40 Fan rotation control unit at the time of high CO generation 42 Fan rotation control unit at the time of current rise 44 Fan rotation control unit with combined flame rod current value and CO concentration

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kikuo Okamoto 3-4 Fukamidai, Yamato-shi, Kanagawa Prefecture Inside Gaster Co., Ltd. (72) Inventor Kazuyuki Iizumi 3-4 Fukamidai, Yamato-shi, Kanagawa Prefecture Gaster Co., Ltd. (72) Inventor Akihiro Nirasawa 3-4 Fukamidai, Yamato City, Kanagawa Prefecture Inside Gaster Co., Ltd. (72) Inventor Naoyuki 3-4 Fukamidai, Yamato City, Kanagawa Prefecture Inside Gaster Co., Ltd. 3-4 Fukamidai, Yamato-shi

Claims (5)

[Claims] The combustion is performed using air supplied by the rotational drive of a combustion fan, and the combustion capacity can be variably controlled. The number of revolutions of the combustion fan is given in accordance with the combustion capacity. In a combustion device having fan rotation control data and performing rotation control of the combustion fan based on the combustion capability and the fan rotation control data, a plurality of stages of fan rotation control data having different combustion engine rotation speeds with respect to the combustion capability are stored in advance. The change in the combustion capacity is monitored, and if the combustion capacity decreases by a predetermined amount of change in the capacity reduction, the fan rotation control data is set to a value higher than the fan rotation control data before the change in the capacity. Switching to high fan rotation control data, and based on the fan rotation control data, continuously rotating the combustion fan until a predetermined standby time elapses. A combustion device, comprising: a fan rotation control unit for changing the fan rotation control data on the low fan rotation speed side after performing the control. 2. A CO sensor for detecting the CO concentration in the exhaust gas is provided, the CO concentration in the exhaust gas detected and output by the CO sensor is monitored, and before the performance decrease is changed by the fan rotation control unit at the time of the performance decrease change. When the rotation speed of the combustion fan is switched to the fan rotation control data having a higher fan rotation speed than that of the fan rotation control data, the CO concentration in the exhaust gas rises above a predetermined dangerous value. After switching to high fan rotation control data with a high fan rotation speed, reducing the rotation speed of the combustion fan to the fan rotation speed after the capacity change, and continuing the reduced rotation speed of the combustion fan until a predetermined standby time has elapsed, High C for switching to low fan speed control data
The combustion device according to claim 1, further comprising a fan rotation control unit when O is generated. 3. A flame rod electrode for detecting a combustion flame is provided, and a flame rod current value detected and output by the flame rod electrode is monitored, and a fan rotation control unit at the time of a performance reduction change is used to control a fan rotation before the performance reduction. When the flame rod current value rises above a predetermined upper threshold while the combustion fan rotation control is being performed by switching to the fan rotation control data having a larger fan rotation speed than the control data, the fan rotation speed is further increased. After switching to high fan rotation control data to reduce the rotation speed of the combustion fan to the fan rotation speed after the capacity change, and after continuously performing the reduced rotation speed of the combustion fan until a predetermined standby time elapses, It is equipped with a fan rotation control unit at the time of current rise that switches to the fan rotation control data on the low fan rotation speed side. The combustion device according to claim 1, wherein 4. A flame rod electrode for detecting a combustion flame and a CO sensor for detecting a CO concentration in exhaust gas, wherein a flame rod current value detected and output by the flame rod electrode and a CO sensor are detected. The CO concentration in the output exhaust gas and the combustion performance are monitored, and when the performance is changed, the fan rotation control unit switches to the fan rotation control data having a higher fan rotation speed than the fan rotation control data before the performance reduction. During the rotation control of the combustion fan, when the combustion capacity is below the predetermined combustion capacity and the flame rod current value rises above the predetermined upper threshold, or the CO concentration in the exhaust gas Is higher than a predetermined risk value, the fan speed is switched to the fan speed control data with a higher fan speed and the combustion fan speed is increased. A flame rod current for reducing the rotation speed of the combustion fan to the fan rotation speed after the capacity change, continuing the reduced rotation speed of the combustion fan until a predetermined standby time elapses, and then switching to the lower fan rotation speed side fan rotation control data. 2. The combustion apparatus according to claim 1, further comprising a fan rotation control unit that uses a value and a CO concentration. 5. Using fan air volume control data in which the air flow rate of the combustion fan is given in accordance with the combustion capacity, instead of fan rotation control data in which the number of revolutions of the combustion fan is given in accordance with the combustion capacity, 5. The combustion apparatus according to claim 1, wherein an air flow corresponding to the combustion capacity is controlled by a rotation speed of a combustion fan.