JP3029547B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In a combustion apparatus of this kind, even when a supply / exhaust passage communicating with a combustion chamber such as an exhaust duct is somewhat blocked, combustion air is forcibly supplied in accordance with a required amount of combustion to perform combustion. It is preferable to maintain good. For this reason, while controlling the combustion fan to rotate at the target rotation speed corresponding to the required combustion amount, the current value of the combustion fan during combustion is detected, and the degree of decrease in the detected fan current with respect to the reference fan current in the normal state. (In the case where the target rotation speed is constant, utilizing the fact that the higher the degree of blockage, the lower the fan current decreases), and calculating a correction value of the target rotation speed of the combustion fan based on the degree of blockage, A method of correcting the target rotation speed with the correction value has been considered.

However, in the above case, for example, when a large gust is blown into the exhaust duct and the degree of blockage temporarily increases, the rotation speed of the combustion fan is greatly corrected.
When the gust is stopped and the closed state is released, although temporarily, the amount of combustion air becomes significantly larger than the required amount of combustion, and there is a possibility that a misfire or the like may occur.

[0004]

SUMMARY OF THE INVENTION The present invention solves such inconveniences and can supply a combustion air amount corresponding to a required combustion amount in accordance with a closed state of a supply / exhaust passage communicating with a combustion chamber. It is another object of the present invention to provide a combustion apparatus which can reduce the influence of a temporary blockage state such as a gust and can continue combustion satisfactorily.

[0005]

In order to achieve the above object, a first aspect of the present invention is to provide a combustion chamber containing a burner, a supply / exhaust passage communicating with the combustion chamber, and a combustion chamber for the burner. A combustion fan for supplying air for use, a degree of blockage detection means for detecting a degree of blockage of a supply / exhaust passage communicating with the combustion chamber, and a target rotation speed at which a target combustion air amount corresponding to a required combustion amount of the burner is obtained. And a rotation speed correction unit that corrects the target rotation speed of the combustion fan so that a target combustion air amount is obtained according to the degree of blockage detected by the degree of blockage detection unit. The combustion device further includes a correction value calculating unit that calculates a correction value of a target rotation speed corresponding to the degree of blockage detected by the blockage degree detection unit, wherein the rotation speed correction unit includes a correction value obtained by the correction value calculation unit. By eye When correcting the rotational speed, and corrects the target rotational speed so as to gradually become corrected target rotational speed.

The correction value gradually increases from the state before the start of correction and changes so as to reach the correction value after a predetermined time, so that the correction value for each unit time is multiplied by the target rotation speed. I do.

In a second aspect of the present invention, a combustion chamber for accommodating a burner, a supply / exhaust passage communicating with the combustion chamber, a combustion fan for supplying combustion air to the burner, and the combustion chamber A degree-of-clogging detection means for detecting the degree of blockage of the supply / exhaust passage to the engine; and a number-of-rotations setting means for setting a target number of rotations at which a target combustion air amount corresponding to a required combustion amount of the burner is obtained.
A rotation speed correction unit that corrects a target rotation speed of the combustion fan so that a target combustion air amount is obtained in accordance with the degree of blockage detected by the blockage degree detection unit. Correction value calculation means for calculating a correction value of the target rotation speed corresponding to the degree of blockage detected, the rotation speed correction means, when correcting the target rotation speed by the correction value obtained by the correction value calculation means, The target rotation speed is corrected by limiting the upper limit of the correction value to a predetermined value.

[0008] The correction value may be multiplied by a target rotation speed, and an upper limit value of the correction value may be determined. The upper limit value is a value set in advance so that even if the closed state is released due to the stoppage of a gust or the like, the amount of combustion air does not become excessive and combustion failure does not occur.

[0009] The degree of blockage detection means may detect the degree of blockage based on the degree of decrease in the detected fan current of the combustion fan described in the above-described prior art, and may further measure the amount of air blown from the combustion fan. Detected by the sensor,
The degree of blockage may be detected by comparing this with the target air flow rate corresponding to the required combustion amount, and the correction value calculation means may adjust the degree of blockage of the combustion fan in accordance with the degree of blockage detected based on the air flow rate. Means for calculating a correction value for correcting the target rotation speed may be used.

[0010]

According to the first aspect of the present invention, the rotation speed correction means corrects the target rotation speed based on the correction value calculated by the correction value calculation means. At this time, the target rotation speed is corrected so that the target rotation speed gradually reaches the corrected target rotation speed without being corrected all at once to the target rotation speed corrected by the correction value.

Since a time lag occurs before the corrected target rotational speed is reached, a rapid increase in the target rotational speed does not occur in a short-time blockage state due to the effect of gusts, and the burner does not increase. There is no large change in the amount of combustion air supplied to the air conditioner.

On the other hand, if the closed state is not temporary but continuous, the target rotational speed is gradually corrected so that the amount of combustion air required according to the degree of blockage is obtained. The corrected target rotation speed is reached.

As described above, in order to gradually reach the corrected target rotational speed, the correction value is increased every unit time from the state before correction, and reaches the correction value after a predetermined time. , By multiplying the target rotation speed by a correction value that increases every unit time.

According to a second aspect of the present invention, the rotation speed correction means corrects the target rotation speed based on the correction value calculated by the correction value calculation means. Then, when the rotation speed correction means corrects the target rotation speed with the correction value obtained by the correction value calculation means, the calculated correction value is compared with a predetermined value, and the correction value exceeds the predetermined value. In some cases, the correction value is limited to a predetermined value and the target rotational speed is corrected. When the correction value falls below the predetermined value, the correction is made with the correction value.

The target rotation speed corrected in this manner is corrected by a correction value limited by a predetermined value. Therefore, even if a sudden and large short-time blockage state occurs due to the influence of a gust, the target rotation speed is sharply reduced. The number is largely corrected and the combustion air does not increase. Even if the gust is stopped, the combustion air amount is prevented from increasing significantly with respect to the required combustion amount, and no misfire occurs.

The correction of the target rotation speed is performed by multiplying the correction value by the target rotation speed, and by setting an upper limit value of the correction value.

On the other hand, if the closed state is not temporary but continuous, the upper limit of the correction value is limited while the upper limit of the correction value is limited so that the amount of combustion air required in accordance with the degree of blockage can be obtained. When the rotational speed is corrected and such a correction time continues for a predetermined time, combustion is stopped by the safe driving means.

By using the first and second aspects of the present invention together, it is possible to reduce the combustion speed caused by the correction of the target rotation speed, which occurs after the short-time blockage due to the above-mentioned gusts or the like. Insufficient combustion due to an excessive amount of air is more effectively suppressed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a water heater A as a combustor is
A water heater main body K installed outdoors and a remote controller L installed in a kitchen or the like and connected to the water heater main body K by a two-wire wire N are provided.

The water heater main body K includes a heat exchange water passage 1, a gas burner 2, a combustion housing 3, a combustion fan 4 for introducing combustion air into the combustion housing 3, and a control unit 5.
And

The heat exchange channel 1 includes a water supply pipe 11, a heat exchanger pipe 1
2, a bypass pipe 13 and a tapping pipe 14. The upstream side of the water supply pipe 11 is connected to the water supply, and the downstream side is connected to the inlet of the electric water flow control device 15. The water supply pipe 11 is provided with a water filter / water drainage plug 11 from the upstream side.
1. A water sensor 112 and a water supply thermistor 113 are provided. The heat exchanger tube 12 has an upstream inlet side connected to one outlet side of the electric water flow control device 15, and a heat exchanger 12 on the way.
1 is disposed above the gas burner 2, and the downstream outlet side is connected to the tapping pipe 14. The heat exchanger 121 heats water passing therethrough. In addition, an overheat prevention device 122 is provided on the outer wall.
Is disposed on the downstream exit side.
23 are provided.

The bypass pipe 13 has an upstream inlet connected to the other outlet of the electric water flow control device 15 and a downstream end connected to the upstream of the tapping pipe 14 (downstream end of the heat exchanger pipe 12). The hot water pipe 14 is provided with a freezing prevention heater 141 for preventing freezing, a hot water thermistor 142 for detecting hot water temperature, an overpressure safety valve / water tap 143, and a hot water tap 144 for discharging hot water from the upstream side to the downstream side. Has been established.

The electric water flow control device 15 is energized and controlled by the actuator control section 58, and outputs the amount of water passing through the water supply pipe 11, the amount of heat exchange water passing through the heat exchanger tube 12, and the hot water without passing through the heat exchanger tube 12. Bypass pipe 13 reaching pipe 14
Is controlled with respect to the amount of bypass water flowing through the water (heat exchange water amount 1 constant). Hot water tap 144 is a hot water tap for adjusting the amount of hot water discharged from a faucet provided in a kitchen or a bathroom. The water amount sensor 112 is of an impeller type and sends out a pulse corresponding to the amount of water flowing in the water supply pipe 11.

The gas burner 2 of the three-stage switching type is disposed inside the combustion housing 3 and is supplied with combustion air by a combustion fan 4 and supplied with gas by a gas pipe 6 to perform forced combustion. This gas pipe 6 has an original solenoid valve 6
1, governor proportional solenoid valve 62, capacity switching solenoid valve 63,
64 are provided. Reference numeral 21 denotes an ignition electrode, 22 denotes an igniter, 23 denotes a frame rod for detecting a combustion flame, 24 denotes a temperature fuse for preventing overheating, and 25 denotes a low-temperature sensing switch for operating the freeze prevention heater 14.

The tapping thermistor 142 detects the tapping temperature,
The water supply thermistor 113 is for detecting the water supply temperature. Further, the can body thermistor 123 is provided for detecting the temperature of water passing through the heat exchanger 121.

The performance switching electromagnetic valves 63 and 64 are energized and controlled by the actuator control unit 58, and the combination # 63, 64 of opening and closing the valve is both open, only 63 is open, 64
Only by opening the valve｝, the supply amount to the gas burner 2 is switched in three stages. The flame rod 23 is provided with a burner corresponding to the capacity switching solenoid valve 63 so that the combustion flame can be detected even when only the capacity switching solenoid valve 63 is opened or when only the capacity switching solenoid valve 64 is opened. It is disposed over a burner corresponding to the capacity switching electromagnetic valve 64.

The governor proportional solenoid valve 62 is controlled to be energized by the actuator control unit 58, indicates an opening degree corresponding to the energized amount, and continuously varies the amount of gas flowing through the gas pipe 6. Therefore, the capacity switching solenoid valves 63 and 64 and the governor proportional solenoid valve 6
Combination of 2 and 3 makes it possible to increase the combustion control width and to perform fine control.

The combustion housing 3 has a combustion exhaust gas 3
An exhaust duct 32 is provided for collecting and discharging the exhaust gas 1 to the outside, and an extension duct (not shown) is connected to the exhaust duct 32 as necessary. The remote controller L includes a push button switch for instructing a change in the set temperature, an operation switch 71 for instructing start and stop of operation, a display 72, an operation lamp, a combustion lamp, and the like.

As shown in FIG. 2, a control unit 5 having a microcomputer includes a fan current detecting unit 51 for detecting a fan current, a rotational speed detecting unit 52 for detecting the rotational speed of the combustion fan 4, Control unit 53 for feedback control of air flow, a high blockage monitoring unit 54 for monitoring a high blockage of an air passage (exhaust duct 32 or the like) (for example, a closed state of 90% or more) before ignition, and a blockage of a supply / exhaust passage. A correction value calculation unit 55 for detecting a state and calculating a correction value of the number of revolutions corresponding to the closed state, stopping the ignition corresponding to the closed state, correcting the target number of rotations of the combustion fan 4, and supplying hot water (combustion capacity) A safety operation unit 56 for limiting the amount of heat, a calorific value calculation unit 57, and an actuator control unit 58 for controlling the original electromagnetic valve 61 and the like.

The fan current detecting section 51 includes a current sensor 41
The fan current is detected based on the output of. When the high blockage monitoring unit 54 performs blockage monitoring, the detection of the fan current is performed as follows.
Perform a total of 5 times every 0.5 seconds. The rotation speed detection unit 52
The fan rotation speed is detected based on the output of a rotation speed sensor 42 (such as a Hall element) provided in the combustion fan 4.

A fan control unit (including a fan speed setting means) 53 rotates the combustion fan 4 at a predetermined fan speed (2700 rpm) which is a pre-purge speed before ignition, and an ignition speed (2250 rpm) at the time of ignition. The combustion fan 4 is rotated based on the output of the rotation speed sensor 42 so that the combustion fan 4 rotates at a preset target rotation speed according to the required combustion amount calculated by the calorific value calculation unit 57 during hot water supply. Feedback control. Correction value calculation unit 5 described later
If the correction value calculated by 5 is 1.0 or more and less than 1.2, the safe driving unit 56 increases the rotation speed by multiplying the target rotation speed by the correction value H. As will be described later, at the time of the first hot water supply after the power is turned on, and at the next time when the high blockage monitoring unit 54 operates,
The fan control unit 53 sets the fan predetermined rotation speed, which is the pre-purge rotation speed before the start of ignition, to 3
The combustion fan 4 is rotated at 000 rpm.

During the pre-purge before the start of ignition, the high blockage monitoring unit 54 makes the fan current detection unit 51
The average value of the detected fan currents is a threshold (for example, 400
mA) or less (for example, the blockage rate is equivalent to 90% or more), and the actuator controller 58 is instructed to stop ignition.

The correction value calculation unit 55 detects the closed state of the supply / exhaust passage based on the decrease ratio of the detected fan current to the normal reference fan current of the combustion fan 4 during hot water supply (during combustion). According to the method shown in
A correction value H corresponding to the closed state of the exhaust path is calculated every 20 ms. Therefore, in the present embodiment, the correction value calculation unit 55 also functions as a means for detecting the degree of blockage.

In FIG. 5, reference numeral 81 denotes a steady line indicating the fan speed-fan current characteristic when the fan is not blocked, and reference numeral 82 denotes the fan speed-fan current characteristic at a correction value of 1.0. 83 is a reference value line for determining whether or not the fan speed at the correction value of 1.1
A reference value line 84 indicates a fan current characteristic and determines whether or not to limit the hot water supply capability. Reference numeral 84 indicates a fan rotation speed-fan current characteristic at a correction value of 1.2, and a reference for determining whether to stop hot water supply. Reference numeral 85 denotes an auxiliary value line indicating a fan speed-fan current characteristic determined experimentally for obtaining a correction value.

I ₁ and I ₂ are the auxiliary value lines 8 respectively.
5, and the fan current value at the reference value line 82, I ₀
Is a fan current value detected by the fan current detection unit 51, a is I ₂ -I ₁ , and b is I ₀ -I ₁ . Then, the correction value calculating unit 55 sets the correction value H to ｍ (a / b) −
It is obtained by the formula of 1｝ × α + 1. Here, α is a constant of 1 or less.

FIG. 6 shows the relationship between the correction value H and the closing ratio.
The safe driving unit (rotation speed correction unit) 56 basically corrects the target rotation speed with the correction value H when the correction value H calculated by the correction value calculation unit 55 is 1.0 or more and less than 1.1. , 1.1 to less than 1.2, the target rotation speed is corrected by the correction value H, and the maximum hot water supply capacity (combustion capacity) is limited to No. 14 to No. 10 (in the case of the No. 16 water heater), When the correction value H is 1.2 for a predetermined time (90 seconds), an instruction to stop combustion is issued.

When the target rotation speed is corrected by the correction value H to obtain a corrected target rotation speed, as shown in FIG. 7, the correction value H increases from the state before the start of the correction every unit time, and It changes so as to reach the correction value H after a predetermined time. The target rotation speed is multiplied by a correction value that increases toward the correction value H every unit time (for example, one second). Therefore, the correction value H
Is larger, the time required for correction to the corrected target rotation speed becomes longer. The correction value H has an upper limit of 1.2, and does not change beyond the upper limit. When there is no longer any need for correction due to a gust stop or the like, the correction value H decreases at the same rate as the rate of increase every unit time. In addition, you may make it return to the original target rotational speed at once.

The calorific value calculating section 57 includes a water supply thermistor 113
Is calculated based on the detected water supply temperature detected by the water supply sensor and the detected water supply amount detected by the water amount sensor 112.

The hot water supply apparatus A of this embodiment determines the target rotation speed of the combustion fan 4 based on the required combustion amount, and controls the amount of power to the governor proportional solenoid valve 62 according to the actual rotation speed of the combustion fan 4. Because it is a so-called fan-first control,
When the target rotation speed is corrected, the actuator control unit 58 divides the rotation speed detected by the rotation speed detection unit 52 by a correction value H (a correction value multiplied by the target rotation speed) that changes every unit time. In this way, the capacity switching solenoid valves 63 and 64 are switched to control the amount of electricity supplied to the governor proportional solenoid valve 62 so that the required amount of combustion is canceled by canceling the correction. Further, the electric water flow control device 15 is controlled as necessary to adjust the distribution ratio.
If the fan is not of the fan-first type, there is no need to correct the amount of current supplied to the proportional solenoid valve 62.

Next, the operation of the control unit 5 of the water heater A will be described with reference to the flowcharts shown in FIGS.

The user depresses the operation switch 71 to put the water heater main body K into the operating state, and opens the hot water tap 144.
In STEP1, it is determined whether or not the detected water amount W ≧ 2.7 l / min. If the detected water amount W ≧ 2.7 l / min (YES), the process proceeds to STEP2.

In STEP 2, it is determined whether the flag F is 1 or not. If F = 1 (NO), STEP 3
If the flag F = 1 (YES), the flow proceeds to STEP4. If the correction value H was less than 1.1 (corresponding to a closure rate of less than 60%) at the time of the last hot water supply, the flag is set to 0, and the correction value H is set at the first operation after the power is turned on or at the time of the last hot water supply. If it is 1.1 or more (corresponding to a closure rate of 60% or more), the flag is set to 1. At the first operation after the power is turned on, the water heater is the first operation, and the clogging state has not yet been detected.
The flag is set to 1 because it is desirable to detect a blockage condition by

In STEP 3, the combustion fan 4 is set to the predetermined first
Is instructed to rotate at the (pre-purge) rotation speed (2700 rpm), and the operation proceeds to STEP7. In this case, since the correction value H is less than 1.1 (corresponding to a blocking rate of less than 60%) in the previous combustion, the monitoring of the blocking state before ignition is omitted, and the process proceeds to step 7 of the ignition operation.

On the other hand, when the flag is set to 1, the correction value H is 1.1 or more (corresponding to a blockage rate of 60% or more) in the first operation after the power is turned on or in the previous combustion. In step 4, the combustion fan 4 is set to the first
Is instructed to rotate at a predetermined second (prepurge) rotation speed (3000 rpm) higher than the predetermined rotation speed of
At P5, the high blockage monitoring unit 54 detects a blockage state of the supply / exhaust passage. Specifically, the fan current detector 51
Compares the average value of the fan current detected five times in total every 0.5 seconds with a threshold value (for example, 400 mA; equivalent to a blocking rate of 90%).

In step 6, when average value ≦ threshold (YE
In S), the flow proceeds to STEP 20 in which the combustion fan 4 described below is stopped, assuming that the closing rate is 90% or more. If the average value> the threshold value (NO), the blockage rate is considered to be less than 90% and the STE
Proceed to P7.

In STEP 7, the igniter 22 is activated, and the solenoid valve {source solenoid valve 61, capacity switching solenoid valve 63,
Is opened, the governor proportional solenoid valve 62 is operated (ignition opening) to ignite the gas burner 2, and the operation proceeds to STEP8.
The rotation speed of the combustion fan 4 at this time is determined by the ignition rotation speed (2250 rpm) corresponding to the ignition opening of the governor proportional solenoid valve 62.
m).

In step 8, the flame is detected by the flame rod 23. If the flame is detected (YES), the STE
Proceed to P9. In step 9, the igniter 22 is stopped, and
Proceed to TEP10.

In STEP 10, the blockage state during combustion is detected by the correction calculation unit 55, and combustion proportional control is performed according to the blockage state. On the basis of the detected water supply temperature detected by the water supply thermistor 113 and the detected water supply amount detected by the water amount sensor 112, the calorie calculation unit 57 calculates the required combustion amount at which the tap water temperature reaches the set temperature. The fan control unit 53 performs feedback control of the combustion fan 4 based on the output of the rotation speed sensor 42 so that the combustion fan 4 rotates at a preset target rotation speed according to the required combustion amount calculated by the calorific value calculation unit 57.

The actuator control unit 58 calculates the combustion amount back based on the rotation speed detected by the rotation speed detection unit 52. If the target rotation speed is corrected, the rotation speed detected by the rotation speed detection unit 52 is corrected. When divided by H, the capacity switching solenoid valves 63 and 64 are switched to control the amount of electricity supplied to the governor proportional solenoid valve 62 so as to obtain the combustion amount. Further, the electric water flow control device 15 is controlled as necessary to adjust the distribution ratio.

In STEP 11, the correction calculating section 55 continuously detects the closed state during combustion, calculates a correction value H corresponding to the closed state, and proceeds to STEP 12. ST
In EP12, the correction value calculated by the correction value calculation unit 55 is 1
If it is less than 1.2, the safe driving unit (rotation speed correction unit)
The reference numeral 56 basically corrects the target rotational speed by multiplying the target rotational speed by the correction value H.

More specifically, as shown in FIG. 7, the target rotational speed is corrected as follows. The correction value calculation unit 55 calculates a correction value H according to the degree of blockage at each sampling time (for example, 20 mS). Furthermore,
When the correction value H changes, the correction value changes from the state before the change to the corrected value H after the change at a predetermined rate every unit time (for example, 1S), and changes every unit time. Is multiplied by the target rotational speed, and after a predetermined time, the target rotational speed is corrected by the correction value H. Therefore, even if the change in the correction value H is large, no sharp change in the target rotation speed occurs.

Further, the correction value H is limited to 1.2 as an upper limit value.
The difference between the supplied combustion air amount and the combustion air amount when the correction is canceled (correction value H is 1.0) is prevented from increasing.

In STEP 13, it is determined whether or not the correction value is H1.1 or more (corresponding to a closure rate of 60% or more).
1.1 or more (corresponding to a blocking rate of 60% or more) (Y
ES) proceeds to STEP 14, and if the correction value is less than H1.1 (corresponding to less than 60% of the closing ratio) (NO), the process proceeds to STEP 22 described later.

At STEP 14, the flag F is set to 1, and the routine proceeds to Step 15. In STEP 15, the hot water supply capacity (combustion capacity) is controlled according to the closed state of the supply / exhaust passage.
For example, when the normal maximum hot water supply capacity is No. 16, the capacity is limited as follows. The maximum hot water supply capacity is limited to No. 14 when the blockage rate is 60% or more and less than 65%. The maximum hot water supply capacity is limited to No. 12 when the blockage rate is 65% or more and less than 70%. The maximum hot water supply capacity is limited to No. 11 when the blockage rate is 70% or more and less than 75%. Maximum hot water supply capacity of 10 with blockage rate of 75% or more and less than 80%
Restrict to issue.

If the maximum hot water supply capacity is less than No. 10 in STEP 16 (YES; the correction value H is 1.2 or more / corresponding to the closing rate of 80% or more), the flow proceeds to STEP 23 to be described later, and 1
If the number is 0 or more (NO), the flow proceeds to STEP17.

In STEP 17, it is determined whether or not the detected water amount is W ≦ 2.3 L / min. If W ≦ 2.3 L / min (YES), the flow proceeds to STEP 17, and W> 2.3 L / min. In the case of (NO), the process returns to STEP10.

In STEP 18, the solenoid valve ｛the original solenoid valve 61,
The performance switching solenoid valves 63 and 64 are closed, the governor proportional solenoid valve 62 is deactivated (minimum opening), and the combustion fan 4
Is stopped, and the process proceeds to STEP19.

At STEP 19, the process stands by until hot water tap 144 is opened. When the combustion fan 4 is stopped (the ignition operation is stopped) in STEP20, the process proceeds to STEP21.

In STEP 21, the display 72 is instructed to display the error display "90" {the supply / exhaust passage closing ratio is 90% or more}, and the operation is stopped.

In STEP 22 described above, the flag F is set to 0, and the process proceeds to STEP 17 without changing the maximum hot water supply capacity.

In the aforementioned STEP 23, the correction value H is 1.2
If the above (corresponding to an obstruction rate of 80% or more) has continued for 90 seconds, the flow proceeds to STEP 24, and if not, the flow proceeds to STEP 17.

In STEP 24, the solenoid valve ｛the original solenoid valve 6
1. The performance switching solenoid valves 63 and 64 are closed, the governor proportional solenoid valve 62 is deactivated (minimum opening), the combustion fan 4 is stopped, and the flow proceeds to STEP 25.

In STEP 24, the display 72 is instructed to display the error display "99" {the supply / exhaust passage closing ratio is 80% or more}, and the operation is stopped.

According to the apparatus of the above embodiment, the correction of the target rotation speed by the correction value H calculated by the correction value calculation unit 55 during hot water supply is performed in a state where the target rotation speed is corrected by the correction value H after a predetermined time. So that the amount of combustion air increases sharply even if the blockage progresses rapidly due to gusts etc. Therefore, even if a short-time gust or the like is canceled, the supply amount of combustion air does not greatly increase and misfire can be prevented. Immediately after the occurrence of the blockage state, the combustion air is insufficient, and even if there is a possibility that the combustion state may be slightly affected, no misfire occurs.

The correction value is increased every unit time so as to become the correction value H calculated after a predetermined time, and the target rotation speed is multiplied every unit time, so that a large correction is performed. So that the corrected target rotation speed is reached. As a result, even when the closed state due to a large gust advances, the amount of combustion air does not increase rapidly due to the correction.

Further, since the correction value H is also limited so as not to exceed a predetermined value, even if the closed state progresses greatly due to a gust or the like, an increase in the amount of combustion air due to the correction is limited and the gust or the like is released. Even if it returns to the state where the closed state is released, the fluctuation of the combustion air amount can be suppressed to a width that does not affect the combustion.

Further, if the closed state is not temporary but continuous, the correction value should not exceed a predetermined value so that the amount of combustion air required according to the degree of blockage can be obtained. The target speed is corrected while being limited to
When such a limited correction continues for a predetermined time, the combustion is stopped, so that it is possible to appropriately cope with a continuous excessive blockage state.

The present invention includes the following embodiments in addition to the above embodiment. a. In the above-described embodiment, the setting temperature is variable, but may be fixed (for example, 60 ° C., 75 ° C.). b. It may be adopted in a hot water supply device without a bypass pipe or a hot water supply device of a main stop type. c. In the above embodiment, a hot water supply device is shown as a combustor, but the present invention may be applied to a hot air heater or the like. d. In the above embodiment, the degree of blockage is detected based on the correction value. However, the degree of blockage may be directly detected based on the rate of decrease in fan current. Further, the current value of the fan may be kept constant, and the degree of blockage may be detected based on a change in the number of revolutions. e. In the above embodiment, when the high blockage monitoring unit 54 monitors blockage, the fan current is detected five times in total every 0.5 seconds, but the number and time can be changed as appropriate.
Also in the high blockage monitoring unit 54, similarly to during combustion,
The degree of blockage may be detected by the correction value calculation unit 55. f. The present invention may be applied to a combustion fan provided on the exhaust passage side. g. In the above embodiment, the blockage monitoring by the high blockage monitoring unit 54 is performed during the prepurge, but may be performed separately from the prepurge. h. In the above-described embodiment, the fan-advanced type is shown. However, the proportional-valve-advanced type that determines the number of revolutions of the combustion fan based on the current of the proportional solenoid valve or the parallel type that controls the proportional valve and the combustion fan according to the target combustion amount. It may be a type.

[0069]

According to the first aspect of the present invention, even if the degree of obstruction progresses due to gusts or the like, the number of revolutions of the combustion fan corresponding to the degree of obstruction does not change suddenly. When the state is released within a short time, it is possible to prevent the amount of combustion air from becoming excessive with respect to the required amount of combustion, and to prevent misfire.

According to the second aspect of the present invention, even when the degree of temporary blockage due to gusts or the like is large, the amount of correction of the amount of combustion air associated therewith is limited. When the state is released, it is possible to prevent the amount of combustion air from becoming excessive with respect to the required amount of combustion, thereby preventing misfire.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a hot water supply apparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram near a control unit of the water heater device.

FIG. 3 is a flowchart illustrating the operation of the water heater.

FIG. 4 is a flowchart illustrating the operation of the water heater.

FIG. 5 is a graph showing the relationship between the number of revolutions of the combustion fan and the fan current.

FIG. 6 is a graph showing a relationship between a closing ratio and a correction value.

FIG. 7 is a graph showing a temporal change of a correction value.

[Explanation of symbols]

A Hot water supply device (combustor) 1 Heat exchange water channel 2 Gas burner 3 Combustion housing 4 Combustion fan 32 Exhaust duct 51 Fan current detection unit (fan current detection unit) 52 Revolution detection unit (revolution detection unit) 53 Fan control unit (fan) Control means, rotation speed setting means) 54 high occlusion monitoring section (high occlusion monitoring means) 55 correction value calculation section (occlusion degree detection means, correction value calculation means) 56 safe driving section (safe driving means, rotation speed correction means)

Continuation of the front page (56) References JP-A-3-186113 (JP, A) JP-A-5-313317 (JP, A) JP-A-7-190343 (JP, A) JP-A 8-75161 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23N 5/24 104 F23N 1/02

Claims (5)

(57) [Claims] A combustion chamber for accommodating a burner; a supply / exhaust passage communicating with the combustion chamber; a combustion fan for supplying combustion air to the burner; and a supply / exhaust passage communicating with the combustion chamber. A degree of blockage detecting means for detecting a degree, a number of rotations setting means for setting a target number of rotations at which a target combustion air amount corresponding to a required combustion amount of the burner is obtained, and a degree of blockage detected by the degree of blockage detected by the degree of blockage. A rotation speed correction means for correcting the target rotation speed of the combustion fan so that a target combustion air amount is obtained. A correction value calculating means for calculating a correction value,
A combustion device that corrects the target rotation speed so as to gradually increase to the corrected target rotation speed when correcting the target rotation speed with the correction value obtained by the correction value calculation unit. . 2. The method according to claim 1, wherein the correction value gradually increases from a state before the start of correction and changes so as to reach the correction value after a predetermined time, and the correction value for each unit time is multiplied by the target rotation speed. The combustion device according to claim 1, characterized in that: 3. A combustion chamber accommodating a burner, a supply / exhaust passage communicating with the combustion chamber, a combustion fan supplying combustion air to the burner, and a blockage of a supply / exhaust passage communicating with the combustion chamber. A degree of blockage detecting means for detecting a degree, a number of rotations setting means for setting a target number of rotations at which a target combustion air amount corresponding to a required combustion amount of the burner is obtained, and a degree of blockage detected by the degree of blockage detected by the degree of blockage. A rotation speed correction means for correcting the target rotation speed of the combustion fan so that a target combustion air amount is obtained. A correction value calculating means for calculating a correction value,
A combustion apparatus, wherein the rotation speed correction means corrects the target rotation speed by limiting the upper limit of the correction value to a predetermined value when correcting the target rotation speed based on the correction value obtained by the correction value calculation means. 4. The combustion apparatus according to claim 3, wherein the correction value is multiplied by a target rotation speed, and an upper limit value of the correction value is determined. 5. A safe driving means for stopping combustion when the correction value exceeds a predetermined value and the target rotational speed is corrected at the predetermined value for a predetermined time. 3. The combustion device according to 3.