JPH08247453A - Combustion device - Google Patents

Abstract

PURPOSE: To provide a combustion device for limiting automatically a combustion capability as a closed state of each of a gas supplying passage and a gas discharging passage is promoted in which a user can be informed strongly of the fact that the combustion capability is being limited in the case that the combustion equipment is being kept at its limited combustion capability. CONSTITUTION: There is provided a correction value calculation part 55 for calculating a corrected value corresponding to a closed state of each of a gas supplying passage and a gas discharging passage in response to a reducing rate of a sensing fan current. In the case that the calculated correction value is kept at its medium level, a safety operating part 56 delays an ignition at a next hot water feeding start time and further causes a user to acknowledge strongly that the operation is limiting a hot water feeding capability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a combustor such as a water heater.

[0002]

2. Description of the Related Art A combustor that incorporates a combustion failure prevention device that detects a combustion failure with a thermocouple or the like and extinguishes the fire (stops operation) is known because the combustion failure occurs when the supply / exhaust passage is blocked. Has been.

[0003]

The above-mentioned conventional techniques have the following drawbacks. It is inconvenient because the combustor cannot be used after the fire is extinguished (stopped operation) due to the blockage of the supply and exhaust passages.

Therefore, the inventors made a prototype of the following combustor with a capability limiting function and examined it. This combustor with a capacity limiting function has an exhaust duct for discharging combustion exhaust gas to the outside, a combustion housing in which a gas burner is installed, a combustion fan for introducing combustion air into the combustion housing, and a supply / exhaust gas. A coded number (for example, "10") is displayed to indicate that the degree of blockage of the road is detected, the safe driving means that limits the combustion capacity when the degree of blockage is within a predetermined range, and that the hot water supply capacity is being limited. Display means for displaying on the container.

In the combustor with the capacity limiting function, the combustor can be used safely until the degree of blockage of the supply / exhaust passage becomes considerably large, and an indicator indicating whether or not the combustion capacity is being limited is provided. You can tell by looking at.

However, at the time of blockage, the maximum combustion capacity is limited, but since there is no problem in normal use, the user may continue to use until the degree of blockage of the supply / exhaust passage becomes considerably large. There is a problem.

An object of the present invention is to provide a combustor which automatically limits the combustion capacity when the supply / exhaust passage is blocked, and when the combustor is in the combustion capacity limited state, it is strong against the user.
It is to provide a combustor that can let people know that it is under restriction.

[0008]

In order to solve the above-mentioned problems,
The present invention employs the following configuration. (1) A combustion housing having an exhaust duct for discharging combustion exhaust gas to the outside and having a gas burner installed therein, a combustion fan for introducing combustion air into the combustion housing, and a degree of blockage of a supply / exhaust passage are detected. In a combustor equipped with a degree-of-clogging detection means and a safe operation means for limiting the combustion capacity when the degree-of-clogging is within a predetermined range, when combustion capacity is being limited, lowering combustion performance other than combustion capacity limitation Therefore, a means for expressing the ability limitation is provided so that the user can notice the fact that the ability is being limited.

(2) The fan current detecting means for detecting the fan current flowing through the combustion fan, the rotation speed detecting means for detecting the rotation speed of the combustion fan, and the required combustion amount, which have the structure of the above (1). And a fan control unit that feedback-controls the combustion fan so that the combustion fan rotates at a target rotation speed corresponding to, and the blockage degree detection unit detects the blockage degree of the supply / exhaust passage based on the decrease rate of the detected fan current. To do.

(3) Having the configuration of (1) or (2) above, the capacity limitation expression means expresses that combustion capacity is being limited by delaying ignition at the start of combustion.

(4) It has the structure of (1) or (2) above, and the capacity limitation expression means expresses that the combustion capacity is being limited by hunting the heating amount during combustion.

(5) It has the configuration of (1) or (2) above, and the capacity limiting expression means is to limit the combustion capacity by reducing the followability of the heating amount control during combustion. Express.

[0013]

[Action]

[Claim 1] During combustion, the degree of blockage detection means detects the degree of blockage of the supply / exhaust passage. The safe driving means limits the combustion capacity when the degree of blockage is within a predetermined range. When the combustion capacity is being limited, the capacity limitation expression means is activated to reduce the combustion performance other than the combustion capacity limitation. This causes the user to notice that the combustor is under burning capacity limitation.

[Claim 2] After ignition of the gas burner, the fan control means feedback-controls the combustion fan so that the combustion fan rotates at a target rotation speed corresponding to the required combustion amount. The blockage degree detection means detects the blockage degree of the supply / exhaust passage based on the rate of decrease in the detected fan current.

[Claim 3] When the combustion capacity is being restricted, the capacity restriction expressing means delays ignition at the start of combustion. For example, in the water heater, cold water is discharged from the outlet of the heat exchange channel until the gas burner is ignited at the start of hot water supply, and the user notices that the water heater is under burning capacity limitation due to the coldness of the water. This configuration is particularly effective for a known water heater with a Q function. The Q function is a function that eliminates the cold water sandwich phenomenon that occurs during intermittent use of hot water (a drop in hot water temperature that occurs before ignition when re-hot water is supplied).

For example, a heat exchanger tube through a heat exchanger,
By providing a bypass pipe that reaches the hot water outlet pipe without passing through the heat exchanger pipe, and providing a flow rate adjusting valve for varying the water amount of the bypass pipe, and controlling the water amount of the bypass pipe, the hot water outlet temperature at the time of re-hot water supply It prevents the fall of.

As described above, the water heater having the Q function can immediately supply the hot water having the set temperature when the hot water is supplied again immediately (for example, within 8 minutes) after the stop. Therefore, in a water heater having such a Q function, if the configuration of claim 3 is adopted and cold water is discharged for a predetermined time in the event of an abnormality, the user is sure that the water heater has a limited burning capacity. Notice that.

Further, for example, in a warm air heater, cold air blows out until the gas burner is ignited at the start of heating, and the user notices that the warm air heater is under combustion capacity limitation.

[Claim 4] When the combustion capacity is being limited, the capacity limitation expressing means hunts the heating amount during combustion. For example, in a water heater, the user notices that the water heater is under burning capacity limitation due to the change in the temperature of the hot water. Further, for example, in a hot air heater, the user notices that the hot air heater is in the combustion capacity limitation due to a change in the blowing temperature.

[Claim 5] When the combustion capacity is being restricted, the capacity restriction expressing means reduces the followability of the heating amount control during combustion. With this, for example, in a water heater, if the set temperature is reset or the amount of water flowing in the heat exchange channel is changed during hot water supply, the temperature of the hot water does not immediately reach the set hot water temperature, so the user does not Notice that the vessel is under burning capacity limitation.

[0021]

【The invention's effect】

[Claim 1] It is possible to make the user strongly recognize that the combustion capacity is being limited, and there is an effect of prompting a request for inspection.

[Claim 2] Since the degree of blockage of the supply / exhaust passage can be detected with a simple configuration, cost increase can be suppressed to a low level.

[Claim 3] Since ignition is delayed at the start of combustion, the user strongly recognizes that the combustion capacity of the combustor is being limited, and intends to improve the usability. Make an early inspection request. Therefore, it is possible to prevent a situation in which the user continues to use the combustor until the degree of blockage of the supply / exhaust passage becomes considerably large, which is excellent in safety.

[Claim 4] Since the heating amount hunts while the combustion capacity is limited, the user strongly recognizes that the combustion capacity of the combustor is limited and intends to improve the usability. , Make an inspection request early.
Therefore, it is possible to prevent a situation in which the user continues to use the combustor until the degree of blockage of the supply / exhaust passage becomes considerably large, which is excellent in safety.

[Claim 5] Since the followability of the control of the heating amount decreases during the combustion capacity limitation, the user strongly recognizes that the combustion capacity of the combustor is limited, and the usability is good. I want to put it in a state and request an inspection early. Therefore, it is possible to prevent a situation in which the user continues to use the combustor until the degree of blockage of the supply / exhaust passage becomes considerably large, which is excellent in safety.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention (claim 1,
(Corresponding to 2, 3, 5) will be described with reference to FIGS.
As shown in the figure, a hot water supply device A which is a combustor includes 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 N.

The water heater main body K includes a heat exchange channel 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 and a heat exchanger pipe 1.
2, a bypass pipe 13, and a hot water outlet 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 controller 15. The water supply pipe 11 has a water filter / drainage plug 11 from the upstream side.
1, a water amount sensor 112, and a water supply thermistor 113 are arranged.

The heat exchanger tube 12 has an upstream inlet side connected to one outlet side of the electric water amount control device 15, an intermediate heat exchanger 121 disposed above the gas burner 2, and a downstream outlet side connected to the hot water outlet tube 14. Has been done. The heat exchanger 121 heats the water passing through it. Moreover, the overheat prevention device 1 is provided on the outer wall.
22 is provided, and a can body thermistor 123 is provided on the downstream outlet side.
Is provided.

The bypass pipe 13 has an upstream inlet connected to the other outlet of the electric water flow controller 15, and a downstream end connected to an upstream side of the hot water discharge pipe 14 (downstream end of the heat exchanger pipe 12). The hot water outlet pipe 14 is provided with a freeze prevention heater 141 for preventing freezing, a hot water discharge thermistor 142 for detecting the hot water temperature, an overpressure safety valve / drain plug 143, and a hot water tap 144 for discharging hot water from the upstream side to the downstream side. It is set up.

The electric water amount control device 15 is energized and controlled by the actuator control section 58, and the amount of water passing through the water supply pipe 11 and the amount of heat exchange water passing through the heat exchanger pipe 12 and the hot water discharge without passing through the heat exchanger pipe 12 are performed. Bypass pipe 13 reaching pipe 14
Control the ratio with the amount of bypass water flowing through. When the amount of water passing through the water supply pipe 11 is equal to or more than the predetermined amount of water, the amount of heat exchange water is constant and only the amount of bypass water changes. Further, by controlling the electric water amount control device 15 as described below, the Q function described above can be activated, and hot water of the set temperature can be immediately discharged when hot water is reheated. After the hot water supply is stopped, the opening degree of the electric water amount control device 15 is changed every unit time so as to reduce the bypass water amount based on the elapsed time and the incoming water temperature (Example 1). The temperature of the hot water on the outlet side of the heat exchanger 121 is controlled by the can body thermistor 123.
And the opening degree of the electric water flow controller 15 is controlled based on the detected temperature (Example 2).

The hot water tap 144 is a hot water tap for adjusting the amount of hot water discharged from the faucet provided in the kitchen or bathroom. The water amount sensor 112 is an impeller type, and sends out a pulse according to the amount of water flowing through the water supply pipe 11.

The two-stage capacity type gas burner 2 is arranged in the combustion housing 3, and combustion air is sent by the combustion fan 4 and gas is supplied by the gas pipe 6 to combust compulsorily. The gas pipe 6 has a former solenoid valve 61,
Governor proportional solenoid valve 62 and capacity switching solenoid valves 63, 64
Is provided. In addition, 21 is an ignition electrode, 22 is an igniter, 23 is a frame rod for detecting combustion flame, 2
Reference numeral 4 is a thermal fuse, and 25 is a low temperature detection switch.

The tap water thermistor 142 detects the tap water temperature,
The water supply thermistor 113 is for detecting the water supply temperature. Further, the can body thermistor 123 is arranged to detect boiling of water passing through the heat exchanger 121.

The capacity switching solenoid valves 63, 64 are energized and controlled by the actuator control unit 58, and a combination of opening and closing valves {63, 64 are both open, only 63 is open, 64
Only the valve is opened} to switch the gas supply amount to the gas burner 2 in three stages. The governor proportional solenoid valve 62 is energized and controlled by the actuator control unit 58, exhibits an opening degree according to the energization amount, and continuously changes the gas amount flowing through the gas pipe 6. In this way, by combining the capacity switching solenoid valves 63, 64 and the governor proportional solenoid valve 62, the combustion amount control range can be widened and fine control can be performed.

The combustion housing 3 has a combustion exhaust gas 3 at the top.
An exhaust duct 32 for collecting 1 and discharging it is extended. The remote controller L includes a push button switch that gives an instruction to change the set temperature, an operation switch 71 that gives an instruction to start or stop the operation, an indicator 72, an operation lamp, a combustion lamp, and the like.

As shown in FIG. 2, the control unit 5 having a microcomputer includes a fan current detector 51 for detecting a fan current, a rotation speed detector 52 for detecting the rotation speed of the combustion fan 4, and a combustion fan 4. Feedback control of the fan control unit 53, a high blockage monitoring unit 54 for monitoring high blockage (eg, 90% or more blocked state) of the supply / exhaust passage (exhaust duct 32, etc.) before starting ignition, and supply / exhaust A correction value calculation unit 55 that calculates a rotation speed correction value that corresponds to the blocked state of the road, a safe operation unit 56 that performs ignition cancellation, restriction of hot water supply capacity (combustion capacity), and the like corresponding to the blocked state, and a heat amount calculation unit. 5
7 and an actuator control section 58 for controlling the original solenoid 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 fan current is detected by
Perform every 5 seconds for a total of 5 times. The rotation speed detection unit 52
The fan rotation speed is detected based on the output of the rotation speed sensor 42 (Hall element or the like) arranged on the combustion fan 4.

The fan control unit 53 rotates the combustion fan 4 at a predetermined rotation speed (300 rpm) which is the pre-purge rotation speed before ignition, and in advance during hot water supply, according to the required combustion amount calculated by the heat amount calculation unit 57. The combustion fan 4 is feedback-controlled based on the output of the rotation speed sensor 42 so as to rotate at the set target rotation speed. When the correction value calculated by the correction value calculation unit 55 described later is 1 or more and less than 1.2, the target rotation speed is multiplied by the correction value H to increase the target rotation speed.

In the high blockage monitoring section 54, the fan current detecting section 51 makes a total of 5 intervals every 0.5 seconds during the pre-purge before the start of combustion.
The average value of the fan current detected twice is a threshold value (for example, 400
In the case of mA) or less (corresponding to a blocking rate of 90% or more), the actuator controller 58 is instructed to stop the ignition.

The correction value calculation unit 55 uses the method described below to correct the correction value H corresponding to the blocked state of the supply / exhaust passage based on the rate of decrease in the detected fan current during hot water supply (during combustion).
To calculate. In FIG. 5, reference numeral 81 is a steady line showing the fan speed-fan current characteristic when not blocked, and 82 is the fan speed-fan current characteristic at the correction value 1.0, and whether or not correction is performed. Is a reference value line that determines, and 83 is the fan speed at the correction value 1.1.
A reference value line showing the fan current characteristic and deciding whether or not to limit the hot water supply capacity (combustion capacity), 84 shows the fan speed-fan current characteristic at the correction value 1.2,
Reference numeral 85 is a reference value line for deciding whether to stop hot water supply (combustion), and reference numeral 85 is an auxiliary value line showing a fan speed-fan current characteristic determined by an experiment for obtaining a correction value.

I ₁ and I ₂ are auxiliary value lines 8 respectively.
5, and the fan current value on the reference value line 82, I ₀
Is the fan current value detected by the fan current detector 51, a is I ₂ -I ₁ , and b is I ₀ -I ₁ . Then, the correction value calculation unit 55 obtains the correction value H by the formula of {(a / b) -1} × α + 1. Note that α is a constant of 1 or less. FIG. 6 shows the relationship between the correction value H and the blocking rate.

When the correction value H calculated by the correction value calculation unit 55 is 1.0 or more and less than 1.1, the safe driving unit 56 corrects the target rotational speed with the correction value H, 1.1 or more and 1. When it is less than 2, the target rotation speed is corrected with the correction value H, and the maximum hot water supply capacity (combustion capacity) is limited to No. 14 to No. 10.
If it is 2 or more, stop the combustion.

The calorific value calculator 57 is provided with a water supply thermistor 113.
Based on the detected supply water temperature detected by the water supply amount and the detected supply water amount detected by the water amount sensor 112, a required combustion amount at which the outlet water temperature detected by the outlet hot water thermistor 142 reaches the set temperature is calculated.

When the target rotation speed is corrected, the actuator control unit 58 cancels the correction by dividing the rotation speed detected by the rotation speed detection unit 52 by the correction value H to obtain the required combustion amount, and the combustion is performed. Capacity switching solenoid valve 6
By switching between 3 and 64, the amount of electricity supplied to the governor proportional solenoid valve 62 is controlled. If necessary, the electric water flow controller 15 is controlled to adjust the distribution ratio (except when the hot water supply capacity is limited).

Next, the operation of the control unit 5 of the water heater A will be described with reference to the flow charts shown in FIGS. The user presses the operation switch 71 to bring the water heater main body K into an operating state, and opens the hot water tap 144.

In step s1, it is determined whether or not the detected water amount W ≧ 2.7 liters / minute. If W ≧ 2.7 liters / minute (YES), the process proceeds to step s2. Step s2
Thus, the combustion fan 4 has a predetermined rotation speed {prepurge rotation speed (3
00 rpm)}, and the process proceeds to step s3.

In step s3, it is determined whether or not the flag F is 1, and if F = 1 (NO), the process proceeds to step s4. If flag F = 1 (YES), the process proceeds to step s6. The flag is set to 0 when the blockage rate is 60% or more at the first operation after the power is turned on or when the hot water is supplied last time. During the first operation after the power is turned on, the high blockage monitoring unit 54 is set before ignition because the blockage state is not detected yet.
It is desirable to detect the blockage state by.

In step s4, the high blockage monitoring section 54 detects the blockage state of the supply / exhaust passage (it takes about 2.5 seconds for detection). Specifically, the fan current detection unit 51 before starting combustion.
However, the average value of the fan current detected five times every 0.5 seconds is compared with a threshold value (for example, 400 mA; corresponding to a blocking rate of 90%). The detection of the blocked state by the high blockage monitoring unit 54 also has the function of the capacity limitation expressing means of the present invention.

In step s5, if average value ≦ threshold value (Y
ES), assuming that the blockage rate is 90% or more, step s23
Proceed to. If the average value> threshold value (NO), the blocking rate is 9
It is regarded as less than 0% and the process proceeds to step s6.

In step s6, the igniter 22 is activated, and the solenoid valve {original solenoid valve 61, capacity switching solenoid valve 63,
64} is kept open, the governor proportional solenoid valve 62 is operated (ignition opening degree) to ignite the gas burner 2, and the process proceeds to step s7. The rotation speed of the combustion fan 4 at this time is an ignition rotation speed corresponding to the ignition opening of the governor proportional solenoid valve 62.
However, when the correction value is 1.0 or more, the ignition rotation speed is a value obtained by multiplying the target ignition rotation speed by the correction value.

In step s7, the flame rod 23 detects the combustion flame. If detected (YES), the process proceeds to step s8. The igniter 22 is stopped in step s8, and the process proceeds to step s9. In step s9, proportional control is performed as shown below. Based on 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 heat amount calculation unit 57 calculates the required combustion amount at which the hot water temperature reaches the set temperature.

Based on the output of the rotation speed sensor 42, the fan control portion 53 feedback-controls the combustion fan 4 so as to rotate at a preset target rotation speed according to the required combustion amount calculated by the heat quantity calculation portion 57. To do. When the correction value calculated by the correction value calculation unit 55 is 1 or more and less than 1.2, the target rotation speed is corrected by multiplying the target rotation speed by the correction value H.

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 a correction value). Divide by H}, the capacity switching solenoid valves 63 and 64 are switched so that the combustion amount is obtained, and the amount of electricity to the governor proportional solenoid valve 62 is controlled. Also, the electric water flow controller 15 is controlled as necessary to adjust the distribution ratio.

In step s10, based on the above equation,
The correction value calculation unit 55 calculates the correction value H corresponding to the closed state of the supply / exhaust passage, and the process proceeds to step s11. Step s1
In 1, it is determined whether or not the blockage rate is 60% or more (corresponding to the correction value H ≧ 1.1), and when the blockage rate is 60% or more (YE
If S is less than 60% (NO), the process proceeds to step s20.

In step s12, the flag F is set to 0, and the process proceeds to step s13. In step s13, the hot water supply capacity (combustion capacity) is limited according to the closed state of the supply / exhaust passage.

The maximum hot water supply capacity is limited to No. 14 when the blocking rate is 60% or more and less than 65%. The maximum hot water supply capacity is limited to No. 12 when the blocking rate is 65% or more and less than 70%. Blockage rate 70% or more 7
The maximum hot water supply capacity is limited to No. 11 with less than 5%. Occlusion rate 7
The maximum hot water supply capacity is limited to No. 10 at 5% or more and less than 80%. −−−−−−−−−−−−−−−−−−−−−−−−−
−−−

In step s14, the bypass mixing function is stopped (temporarily), and the process proceeds to step s15. If the maximum hot water supply capacity (combustion capacity) is less than No. 10 in step s15 (YES; blockage rate is 80% or more), step s21
If the number is 10 or more (NO), the process proceeds to step s16.

In step s16, it is determined whether or not the detected water amount W ≦ 2.3 liters / minute, and W ≦ 2.3 liters / minute.
Minutes (YES), the process proceeds to step s17, and W> 2.
If it is 3 liters / minute (NO), the process returns to step s9.

In step s17, the solenoid valve {original solenoid valve 6
1. The capacity switching solenoid valves 63, 64} are closed, the governor proportional solenoid valve 62 is deactivated (minimum opening), the combustion fan 4 is stopped, and the process proceeds to step s18.

In step s18, the process waits until the hot water tap 144 opens. In step s19, the flag F is set to 1, and the process proceeds to step s20. In step s20, the bypass mixing function is enabled, and the process proceeds to step s16.

In step s21, the solenoid valve {original solenoid valve 6
1. The capacity switching solenoid valves 63, 64} are closed, the governor proportional solenoid valve 62 is deactivated (minimum opening), the combustion fan 4 is stopped, and the process proceeds to step s22. Step s22
Then, the display 72 is instructed to display the error display "99" (the supply / exhaust passage blockage rate is 80% or more), and the operation is stopped.

In step s23, the combustion fan 4 is stopped and the process proceeds to step s24. In step s24, the display 72 is instructed to display the error code "90" (the supply / exhaust passage blocking rate is 90% or more), and the operation is stopped.

Next, the advantages of the water heater A will be described. [A] When the correction value H calculated by the correction value calculation unit 55 (calculated during hot water supply) is 1.1 or more (blocking rate 60% or more) and less than 1.2 (blocking rate 80%), next time Prior to the start of hot water supply, high obstruction monitoring unit 54 performs high obstruction monitoring to check the high obstruction state, and an ignition delay of 2.5 seconds is provided. Function}.

Therefore, the progress of the closed state of the exhaust duct 32 and the like during the previous hot water supply operation can be checked before ignition, and at the start of hot water supply, cold water is discharged from the hot water plug 144, so that the user can use the hot water supply device. While strongly recognizing that A is in the hot water supply capacity limitation, request an inspection from a service center etc. early in order to correct the discharge of cold water. Therefore, it is possible to prevent a situation in which the user continues to use the water heater until the degree of blockage of the exhaust duct 32 or the like becomes considerably large.

[I] When the correction value H calculated by the correction value calculation unit 55 (calculated during hot water supply) is 1.1 or more and less than 1.2, the actuator control unit 58 stops the bypass mixing function. The followability of the temperature control of the hot water temperature is temporarily reduced. For this reason, when the amount of water is changed or the set temperature is changed, the hot water at the set temperature does not immediately come out, and the user strongly recognizes that the hot water supply device A is in the hot water supply capacity limitation, and the followability of the temperature control is deteriorated. In order to fix the problem, request a service center etc. for inspection early. Therefore, it is possible to prevent a situation in which the user continues to use the water heater until the degree of blockage of the exhaust duct 32 or the like becomes severe.

[U] Blocking state of the supply / exhaust passage (blocking rate 60
% To less than 80%), the maximum hot water supply capacity (combustion capacity) is limited to No. 14 to No. 10. Therefore, the hot water supply device A can be used with a safe hot water supply capacity according to the closed state of the supply / exhaust passage.

A second embodiment of the present invention (corresponding to claims 1, 2, and 4) will be described with reference to FIGS. 1, 2, 7, and 8 (see also FIGS. 5 and 6). Hot water supply apparatus B of the present embodiment differs from hot water supply apparatus A only in the following points. Fan control unit 53 forcibly fluctuates the target rotation speed and the proportional valve current up and down so that the hot water temperature changes periodically (hunting operation).

The control unit 5 of the water heater B has steps S1 to S2 in the flowcharts shown in FIGS.
It operates as shown in 4. In addition, except for steps S14 and S20, the steps correspond to steps s1 to s24 of the water heater A.

In step S14, the target rotational speed of the combustion fan 4 and the proportional valve current corresponding thereto are forcibly changed up and down so that the hot water temperature changes periodically {the fan controller 53 and the actuator controller 58. Corresponds to the capability limitation expression means of the present invention}. In step S20, the hunting of the target rotation speed of the combustion fan 4 and the proportional valve current is stopped.

The hot water supply apparatus B of this embodiment has the above-mentioned [A],
In addition to the advantages according to [U], it has the following advantages. [E] When the correction value H calculated by the correction value calculation unit 55 (calculated during hot water supply) is 1.1 or more and less than 1.2, the target rotation speed and the proportional valve current are forcibly changed up and down. . For this reason, the hot water discharge temperature hunts, and the user is
Strongly recognizes that the hot water supply capacity is limited, and requests the service center etc. for inspection early in order to correct hunting. Therefore, it is possible to prevent a situation in which the user continues to use the water heater until the degree of blockage of the exhaust duct 32 or the like becomes considerably large.

The present invention includes the following embodiments in addition to the above embodiments. a. Although the set temperature is variable in the above embodiment, it may be fixed (for example, 60 ° C. or 75 ° C.). b. The hot water supply device may be of a fixed type. c. Although the hot water supply device is shown as the combustor in the above embodiment, the present invention may be applied to a hot air heater or the like.

D. Although the degree of blockage of the supply / exhaust passage is detected based on the rate of decrease in the detected fan current, a CO sensor or a wind speed sensor may be separately provided and the degree of blockage may be detected by the output of these sensors.

E. In the first embodiment, high obstruction monitoring may not be performed. In this case, as the capability limit expression, it is sufficient to simply delay the ignition operation. f. In the second embodiment, hunting of the hot water outlet temperature may be performed only at the beginning of hot water supply. g. The present invention may be applied to a combustor in which a combustion fan is provided on the exhaust passage side.

[Brief description of drawings]

FIG. 1 is a schematic view of a hot water supply device according to a first embodiment of the present invention.

FIG. 2 is a block diagram in the vicinity of a control unit of the hot water supply device.

FIG. 3 is a flowchart illustrating an operation of the hot water supply device.

FIG. 4 is a flowchart illustrating an operation of the hot water supply device.

FIG. 5 is a graph showing a rotation speed-fan current characteristic of a combustion fan.

FIG. 6 is a graph showing a relationship between a blockage rate and a correction value.

FIG. 7 is a flowchart for explaining the operation of the hot water supply device according to the second embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of the hot water supply device according to the second embodiment of the present invention.

[Explanation of symbols]

A, B Hot water supply device (combustor) 1 Heat exchange channel 2 Gas burner 3 Combustion housing 4 Combustion fan 32 Exhaust duct 51 Fan current detection unit (fan current detection unit) 52 Rotation speed detection unit (rotation speed detection unit) 53 Fan control unit (Fan control means, capacity restriction expression means) 54 High blockage monitoring section (capacity restriction expression means) 55 Correction value calculation section (blocking degree detection means) 56 Safe driving section (safe driving section) 58 Actuator control section (capacity restriction expressing section) )

Claims (5)

[Claims] 1. A combustion housing having an exhaust duct for discharging combustion exhaust gas to the outside and having a gas burner therein, a combustion fan for introducing combustion air into the combustion housing, and a degree of blockage of a supply / exhaust passage. In a combustor equipped with a detection means for detecting the degree of clogging and a safe operation means for limiting the combustion ability when the degree of clogging is within a predetermined range, the combustion performance other than the combustion ability limitation is reduced when the combustion ability is being limited. A combustor characterized by being provided with a means for expressing the ability limitation so that the user can notice the fact that the ability is being limited. 2. A fan current detection means for detecting a fan current flowing through the combustion fan, a rotation speed detection means for detecting a rotation speed of the combustion fan, and a rotation speed of a target rotation speed corresponding to a required combustion amount. The combustor according to claim 1, further comprising: a fan control unit that feedback-controls the combustion fan, wherein the blockage degree detection unit detects a blockage degree of the supply / exhaust passage based on a reduction rate of the detected fan current. 3. The combustor according to claim 1, wherein the capacity limit expression means expresses that the combustion capacity is being limited by delaying ignition at the start of combustion. 4. The combustor according to claim 1, wherein the capacity limitation expression means expresses that the combustion capacity is being limited by hunting a heating amount during combustion. 5. The combustor according to claim 1 or 2, wherein the capacity limitation expression means expresses that the combustion capacity is being limited by reducing the followability of the control of the heating amount during combustion.