JP2021183888A - Combustion device - Google Patents

Abstract

To provide a combustion device capable of suitably igniting a burner which is under on-off control for the combustion of the burner, in a way suitable for controlling the temperature of an object fluid.SOLUTION: A controller 30 of a combustion device (water heater) 1 comprising a burner 4, a fuel feeder 5 and a combustion fan 10, controls the fuel feeder 5 and the combustion fan 10 so as to change the amount of fuel to be fed to the burner 4 and the rotation number of the combustion fan 10 according to heat required for controlling the temperature of the object fluid (water for use in feeding hot water) upon igniting a burner 4 to restart a combustion operation subsequent to extinguishing the burner 4, in the process of on-off controlling the combustion by intermittently carrying out the combustion operation of the burner 4.SELECTED DRAWING: Figure 2

Description

The present invention relates to a combustion device such as a hot water supply device and a heating device.

In a combustion device that heats the target fluid for temperature control such as hot water supply water and heating water by the combustion heat of the burner so that the temperature is maintained at a temperature near the required target temperature, for example, Patent Documents 1 and 2. As can be seen, it has been known conventionally that the combustion operation of the burner is intermittently performed (combustion operation and its suspension are alternately repeated) when the required heat amount required for temperature control of the target fluid is small. Has been done. Hereinafter, the control for intermittently performing the combustion operation of the burner in this way is sometimes referred to as "on-off combustion control" of the burner.

Jitsuzensho 59-23555 Gazette Japanese Unexamined Patent Publication No. 2020-29971

In the techniques found in Patent Documents 1 and 2, in the ignition process when restarting the combustion operation of the burner during the execution of the on / off combustion control of the burner, the amount of fuel supplied to the burner and the combustion air are supplied to the burner. The number of revolutions of the combustion fan for this purpose is controlled without depending on the required heat quantity for controlling the temperature control of the target fluid. Therefore, the amount of combustion heat generated by the burner at the time of ignition for restarting the combustion operation of the burner or immediately after the ignition tends to be excessive or insufficient with respect to the required amount of heat.

In this case, if the amount of heat generated at the time of ignition of the burner or immediately after that is larger than the required amount of heat, the temperature of the target fluid is likely to overshoot with respect to the required target temperature, and the number of revolutions of the combustion fan is increased. Is higher than necessary, so the operating noise of the combustion fan tends to be noisy.

Further, when the amount of heat generated at the time of ignition of the burner or immediately after that is smaller than the required amount of heat, a delay in raising the temperature of the target fluid or frequent ignition failure is likely to occur.

The present invention has been made in view of the above background, and it is intended to provide a combustion device capable of appropriately executing the ignition of the burner in the on / off combustion control of the burner in a form suitable for the temperature control of the target fluid. The purpose.

In order to achieve the above object, the combustion device of the present invention provides a burner that generates heat for heating the target fluid by combustion operation, a fuel supply device that supplies fuel to the burner, and combustion air to the burner. It is a combustion device including a combustion fan to be supplied and a control device having a function of determining a required heat amount for temperature control control of the target fluid and controlling the fuel supply device and the combustion fan according to the required heat amount. hand,
The control device is configured to be able to execute an on-off combustion control process, which is a process of controlling the fuel supply device and the combustion fan so as to intermittently perform the combustion operation of the burner, and the on-off combustion control. In the process, at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire of the burner is extinguished, the amount of fuel supplied to the burner and the rotation speed of the combustion fan are used for controlling the temperature control of the target fluid. It is characterized in that it is configured to control the fuel supply device and the combustion fan so as to change according to a required calorific value (first invention).

In the present invention, "temperature control control" of the target fluid means controlling the temperature of the target fluid so as to match or substantially match the required target temperature.

According to the first invention, in the on / off combustion control process, when the burner is ignited when the burning operation of the burner is restarted after the burner is extinguished, the fuel supply device and the combustion fan are used with the amount of fuel supplied to the burner. The rotation speed of the combustion fan is controlled so as to change according to the required heat quantity for controlling the temperature control of the target fuel. Therefore, it is possible to prevent the temperature of the target fluid from overshooting the required target temperature at the time of ignition of the burner or immediately after the ignition, and to prevent the temperature rise of the target fluid from being delayed. It becomes possible to ignite.

Further, when the burner is ignited after the fire is extinguished, the required heat amount of the burner does not become so large, so that the rotation speed of the combustion fan at the time of ignition can be suppressed to a lower rotation speed, and by extension, the combustion fan at the time of ignition of the burner. It is possible to suppress the operating noise of.
Therefore, according to the first invention, it is possible to appropriately execute the ignition of the burner in the on / off combustion control of the burner in a form suitable for controlling the temperature of the target fluid.

In the first invention, in the on / off combustion control process, the control device operates the combustion fan at a predetermined rotation speed in the fire extinguishing state of the burner, and the air supply / exhaust flow which is a flow path of the combustion air or the combustion exhaust gas. It has a function to detect the degree of blockage of the road, and at least when the degree of blockage is higher than a predetermined value, the temperature control of the target fluid is controlled by the rotation speed of the combustion fan at the time of ignition following the fire extinguishing state of the burner. It is preferable that the combustion fan is configured to be controlled so as to change according to the required amount of heat for use and the degree of blockage (second invention).

According to this, in the on-off combustion control process, by operating the combustion fan at a predetermined rotation speed in the fire extinguishing state of the burner, the degree of blockage of the air supply / exhaust flow path is appropriately detected by using various known methods. be able to. Then, at least when the degree of blockage is higher than a predetermined value, by controlling the combustion fan as described above, the amount of combustion air supplied to the burner tends to decrease as the degree of blockage of the air supply / exhaust flow path increases. It is possible to compensate the effect of the burner and supply the burner with an amount of combustion air commensurate with the required amount of heat. Therefore, even if the air supply / exhaust flow path is blocked to some extent, the burner can be ignited satisfactorily with an appropriate required heat amount.

In the first invention, in the on / off combustion control process, the control device operates the combustion fan at a predetermined rotation speed while the burner is extinguished, and the supply / exhaust flow is a flow path of combustion air or combustion exhaust gas. It has a function to detect the degree of blockage of the road, and when the degree of blockage is lower than a predetermined value, the burner is ignited when the combustion operation of the burner is restarted after the burner is extinguished. The fuel supply device and the combustion fan are controlled so that the fuel supply amount and the rotation speed of the combustion fan are changed according to the required heat amount for temperature control of the target fluid, and the degree of blockage is more than a predetermined value. When it is too high, the fuel supply device is controlled so that the amount of fuel supplied to the burner at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire of the burner is extinguished is controlled and the combustion is performed. It is also possible to adopt an embodiment in which the combustion fan is controlled so that the rotation speed of the fan becomes a rotation speed set according to the degree of blockage (third invention).

According to this, as in the second invention, in the on / off combustion control process, the combustion fan is operated at a predetermined rotation speed in the fire extinguishing state of the burner, so that the air supply / exhaust flow path can be operated by various known methods. The degree of blockage can be appropriately detected. Then, when the degree of blockage is lower than the predetermined value, the effect described in the first invention can be obtained by controlling the fuel supply device and the combustion fan as in the first invention.

When the degree of blockage of the air supply / exhaust flow path is higher than a predetermined value, the fuel supply device and the combustion fan are controlled as described above to restart the combustion operation of the burner after the burner is extinguished. The fuel supply device is controlled so that the amount of fuel supplied to the burner at the time of ignition of the burner is a predetermined amount, and the rotation speed of the combustion fan is set to a rotation speed set according to the degree of blockage. By controlling the combustion fan, it compensates for the effect that the supply amount of combustion air to the burner tends to decrease as the degree of blockage of the air supply / exhaust flow path increases, and the ignition of the burner is stable and good. It will be possible to do it.

In the first to third inventions, if the ignition of the burner is not detected at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire of the burner is extinguished, the control device is supplied to the burner. It is preferable that the fuel supply device and the combustion fan are controlled so as to increase the fuel supply amount and the rotation speed of the combustion fan more than at the time of ignition when the ignition is not detected (first). 4 invention).

According to this, when non-ignition occurs due to ignition failure at the time of ignition after extinguishing the burner in the on-off combustion control process, the fuel supply amount to the burner and the rotation speed of the combustion fan are increased, and then the burner is used. Since the reignition is performed, the certainty of normal ignition of the burner due to the reignition can be increased.

The figure which shows outline the whole structure of the hot water supply device as an example of the combustion device of an embodiment. The flowchart which shows the process in 1st Embodiment of the control apparatus shown in FIG. The flowchart which shows the process in 2nd Embodiment of the control apparatus shown in FIG.

[First Embodiment]
The first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. With reference to FIG. 1, the water heater 1 of the present embodiment has a heat source machine 2 installed outdoors. The heat source machine 2 is equipped with a combustion chamber 3 that forms a combustion chamber 3a inside, and a burner 4 as a heating unit is arranged below the combustion chamber 3a in the combustion chamber 3.

The burner 4 is a gas burner in the present embodiment, and is composed of a plurality of burners capable of performing combustion operation separately, for example, three burners of a first burner 4a, a second burner 4b, and a third burner 4c. In the illustrated example, the first burner 4a, the second burner 4b, and the third burner 4c have different combustion areas from each other, but the combustion areas of the two or more burners constituting the burner 4 are different from each other. It may be the same.

The heat source machine 2 is equipped with a fuel supply device 5 for supplying fuel gas to the burner 4. The fuel supply device 5 has a main gas supply path 6 to which fuel gas is supplied from a gas supply source (not shown), and three sub gas supply paths 6a, 6b, 6c branched from the main gas supply path 6. .. Each of the auxiliary gas supply paths 6a, 6b, 6c is supplied to the combustion chamber 3a from the outside of the combustion chamber 3 so that fuel gas can be separately supplied to each of the first burner 4a, the second burner 4b, and the third burner 4c. Has been introduced.

The fuel supply device 5 further adjusts the supply amount of the fuel gas to the main valve 7 and the burner 4 interposed in the main gas supply path 6 so as to open and close the main gas supply path 6. The gas amount adjusting valve 8 interposed in the supply passage 6 and the switching valve interposed in each of the auxiliary gas supply passages 6a, 6b, 6c so as to be able to open and close each of the auxiliary gas supply passages 6a, 6b, 6c. It includes 9a, 9b, and 9c. Each of the main valve 7 and the switching valves 9a, 9b, 9c is composed of, for example, a solenoid valve, and the gas amount adjusting valve 8 is composed of, for example, a proportional valve or an electric flow rate control valve.

In the present embodiment, since the fuel supply device 5 is configured as described above, the switching valves 9a, 9b, and 9c are opened and closed while the main valve 7 is controlled to open during the combustion operation of the burner 4. By switching the combination of the above, it is possible to change the total amount of combustion heat of the burner 4 in a wide range. The burner 4 is not limited to the one composed of a plurality of novelrs capable of performing combustion operation separately, and the entire burner 4 may be configured to perform combustion operation at the same time. In other words, the fuel gas may be supplied from a single gas supply path to the entire burner 4.

Further, the heat source machine 2 is equipped with an electric combustion fan 10 as a blower for supplying combustion air to the burner 4. The combustion fan 10 sucks in outside air as combustion air by its rotational operation, and burns so that the sucked combustion air can be supplied to the burners 4 (the whole of the first to third burners 4a, 4b, 4c). It is attached to the lower part of the housing 3. Then, by variably controlling the rotation speed (rotational speed) of the combustion fan 10, it is possible to change the amount of combustion air supplied to the burner 4.

An exhaust port 3b for exhausting the combustion exhaust gas of the burner 4 from the combustion chamber 3a is provided in the upper part of the combustion casing 3. The exhaust port 3b communicates with the outside of the heat source machine 2 via an exhaust passage (not shown). Further, in the combustion casing 3, by operating an igniter (not shown) mounted on the heat source machine 2, an ignition electrode 12 for generating a spark discharge for igniting the burner 4 and the presence / absence of a combustion flame of the burner 4 are detected. A flame detection sensor 13 for this purpose is attached. The flame detection sensor 13 is composed of, for example, a frame rod, a thermoelectric pair, or the like.

In addition to the above configuration related to the combustion operation of the burner 4, the heat source machine 2 is also provided with a configuration related to the passage of hot water for hot water supply as a target fluid (fluid to be heated). Specifically, the combustion chamber 3a in the combustion casing 3 is provided with a heat exchanger 21 arranged so as to be heated by the combustion heat of the burner 4. A water passage 22 capable of passing water via the heat exchanger 21 is provided.

The water passage 22 is connected to the inlet of the water passage 21a of the heat exchanger 21, and is connected to the water supply passage 22a to which water for hot water is supplied from a water supply source (not shown) and the outlet of the water passage 21a of the heat exchanger 21. It includes a hot water supply passage 22b and a bypass passage 22c that connects the water supply passage 22a to the hot water supply passage 22b so that the heat exchanger 21 can be bypassed from the water supply passage 22a and the hot water supply water can be circulated to the hot water supply passage 22b. The downstream side of the hot water supply passage 22b is arranged so as to be able to supply hot water supply water to a hot water supply target portion (curan or the like) (not shown) such as a kitchen, a washroom, and a bathroom.

Therefore, during the combustion operation of the burner 4, the hot water supply water heated from the water supply passage 22a via the heat exchanger 21 and the hot water supply water from the water supply passage 22a via the bypass passage 22c are merged in the hot water supply passage 22b. The water passage 22 is configured so that the hot water to be supplied can be supplied from the hot water supply passage 22b to the hot water supply target portion.

In the water supply channel 22a, an electric water amount control valve 23 for adjusting the water supply flow rate, which is the water flow rate of the water supply channel 22a, and a water amount sensor 24 for detecting the water supply flow rate are branched portions of the bypass path 22c. It is installed on the upstream side of. Further, in the hot water supply passage 22b, a temperature sensor 25 that detects the hot water supply temperature which is the temperature of the hot water supply water supplied to the hot water supply target portion (the temperature of the hot water water flowing downstream from the connection portion between the bypass path 22c and the hot water supply passage 22b). A temperature sensor 26 for detecting the hot water outlet temperature of the heat exchanger, which is the temperature of the hot water supply water flowing out from the heat exchanger 21 to the hot water supply passage 22b, is attached.

The control valve for adjusting the ratio (so-called bypass ratio) between the flow rate of the hot water supply water passing through the bypass path 22c and the flow rate of the hot water supply water passing through the water passage 21a of the heat exchanger 21 is the bypass path 22c and the water supply. It may be provided in the connection portion with the road 22a or the hot water supply passage 22b, or in the middle of the bypass road 22c.

Next, the configuration related to the operation control of the hot water supply device 1 (including the combustion operation control of the burner 4) will be described. The hot water supply device 1 includes a control device 30 having a function of controlling the operation thereof, and a remote controller 40 for operating the hot water supply device 1.

The remote controller 40 is a terminal installed in a kitchen, a bathroom, or the like, and is provided with a plurality of operation switches, indicators, and the like (not shown). By operating the operation switch of the remote controller 40, it is possible to perform operations such as turning on / off the hot water supply operation of the hot water supply device 1 and setting a target value (hereinafter referred to as a target hot water supply temperature) of the hot water supply temperature. The hot water supply device 1 may include a plurality of remote controllers including the remote controller 40.

The control device 30 is composed of one or more electronic circuit units including a microcomputer (not shown), a memory, an interface circuit, and the like, and is mounted on the heat source machine 2. The control device 30 can communicate with the remote controller 40 by wire or wirelessly, and the operation information of the remote controller 40 (on / off signal of hot water supply operation, set value of target hot water supply temperature, etc.) is input by this communication. NS. Further, a detection signal of each sensor (including the flame detection sensor 13, the water amount sensor 24, and the temperature sensors 25 and 26) provided in the hot water supply device 1 is input to the control device 30.

The control device 30 has a function of controlling the combustion operation of the burner 4 as a function realized by one or both of the mounted hardware configuration and the program (software configuration).

Next, the operation of the hot water supply device 1 of the present embodiment will be described. The control device 30 monitors the presence or absence of water flow in the water passage 22 based on the output of the water volume sensor 24, and when it detects the occurrence of water flow in the water passage 22 exceeding a predetermined flow rate, the combustion operation of the burner 4 is performed. To do. In this case, the control device 30 controls the amount of combustion heat of the burner 4 after igniting the burner 4, so that the hot water supply temperature detected by the temperature sensor 25 matches or almost matches the target hot water supply temperature set by the remote controller 40. Control the temperature of the hot water to match.

In this temperature control, the control device 30 intermittently performs the continuous combustion control process as the control process for continuously performing the combustion operation of the burner 4 and the combustion operation of the burner 4 (combustion operation of the burner 4). The on / off combustion control process as the control process (which repeats the stop alternately) is selectively executed.

In the present embodiment, the control device 30 has, for example, when the set target hot water supply temperature is equal to or higher than a predetermined temperature, or the required heat amount which is a required value of the combustion heat amount of the burner 4 for controlling the temperature control of the hot water supply water. , When the value is equal to or higher than the predetermined value, the continuous combustion control process is executed. Further, the control device 30 controls on / off combustion when the set target hot water supply temperature is lower than the predetermined temperature, or when the required heat amount of the burner 4 for controlling the temperature control of the hot water supply water is lower than the predetermined value. Execute the process.

In the continuous combustion control process, after the burner 4 is ignited, the control device 30 determines the required heat amount of the burner 4, the detected value of the temperature of the hot water supply water detected by the temperature sensors 25 and 26, and the hot water supply detected by the water amount sensor 24, respectively. It is sequentially determined based on the detected value of the flow rate of irrigation water, etc., and the switching valves 9a, 9b, 9c of the fuel supply device 5 are controlled to open and close according to the determined required heat amount, and the required heat amount is required. The amount of fuel gas supplied to the burner 4 and the amount of combustion air supplied are controlled so as to be realized by the combustion operation of the burner 4 at the air-fuel ratio of. In this case, the control of the fuel gas supply amount is performed through the control of the gas amount control valve 8, and the control of the combustion air supply amount is performed through the control of the rotation speed of the combustion fan 10.

On the other hand, in the on-off combustion control process, when the target hot water supply temperature is set to a temperature lower than the predetermined temperature and water flow through the water passage 22 (water flow above the predetermined flow rate) is started, or continuous combustion is performed. When the target hot water supply temperature is changed to a temperature lower than the predetermined temperature during the combustion operation of the burner 4 by the control process, or due to the change of the target hot water supply temperature, the required heat amount of the burner 4 is less than the predetermined value. When it becomes low, it is executed as shown in the flowchart of FIG.

Specifically, the control device 30 determines in STEP 1 whether or not the burner 4 is in combustion operation, and if the determination result is positive, executes the process from STEP 13 described later. If the determination result of STEP 1 is negative, the control device 30 sequentially repeats the process of determining whether or not there is an ignition request for the burner 4 in STEP 2 until the determination result becomes affirmative. ..

In this case, for example, when it is confirmed that there is no abnormality in the hot water supply device 1 in the initial check process immediately after the start of water flow of a predetermined flow rate or more in the water passage 22, the determination result of STEP 2 becomes affirmative. At this time, the control device 30 drives the combustion fan 10 at a predetermined low rotation speed for purging the combustion chamber 3a in STEP3. Then, the control device 30 determines whether or not the degree of blockage of the air supply / exhaust flow path (supply air flow path or exhaust flow path) communicating with the combustion chamber 3a is higher than a predetermined threshold value while the combustion fan 10 is operating. do.

Here, in the present embodiment, in STEP 4, the control device 30 uses the detected value of the fan current, which is the energizing current of the electric motor (not shown) for driving the combustion fan 10, as an index value indicating the degree of blockage of the air supply / exhaust flow path. Obtained via a current sensor (not shown). Then, the control device 30 determines that the determination result of STEP 4 is positive when the detected value of the fan current is lower than the predetermined value, and when the detected value of the fan current is equal to or more than the predetermined value, STEP 4 is performed. Judge that the judgment result is negative.

The degree of blockage of the air supply / exhaust flow path may be determined by using another method. For example, it is also possible to detect the air volume or pressure of the air supply / exhaust flow path and use the detected values to determine the degree of blockage of the air supply / exhaust flow path.

If the determination result of STEP 4 is negative, the control device 30 calculates the required heat amount of the burner 4 for controlling the temperature control of the hot water supply water in STEP 5, and turns on / off the burner 4 according to the required heat amount. The ignition rotation speed for on-off combustion, which is the target rotation speed of the combustion fan 10 at the time of ignition of the burner 4 during execution of the combustion control process, is determined. The ignition rotation speed for the on-off combustion is determined from the required heat quantity by using a map or an arithmetic expression created in advance. In this case, the ignition rotation speed for on-off combustion is determined so as to increase as the required heat amount increases within a range from a predetermined lower limit value to an upper limit value.

The control device 30 further determines in STEP 7 whether or not the burner 4 was burned immediately before (in other words, whether or not the combustion operation of the burner 4 in the on / off combustion control process is suspended). In this case, when the first (first) combustion operation of the burner 4 in the on / off combustion control process is started, the determination result of STEP 7 becomes negative. At this time, the control device 30 executes the ignition process of the burner 4 in STEP 8.

In this ignition process, the control device 30 operates the combustion fan 10 at a normal ignition speed. The normal ignition rotation speed is the same as the rotation speed of the combustion fan 10 in the ignition processing of the burner 4 at the start of the continuous combustion control processing, and is the rotation speed corresponding to the minimum required heat amount and the maximum in the continuous combustion control processing. It is a predetermined predetermined rotation speed between the rotation speed corresponding to the required heat quantity of.

In the ignition process of STEP 8, the control device 30 further applies a predetermined flow rate of fuel gas corresponding to the normal ignition rotation speed of the combustion fan 10 to a predetermined burner for on / off combustion control process in the burner 4, for example, the first burner. An igniter (not shown) is operated while controlling the opening of the main valve 7 and the switching valve 9a and the control of the gas amount adjusting valve 8 so as to supply the gas to 4a. In this case, the control value of the gas amount adjusting valve 8 corresponding to the fuel gas having a predetermined flow rate is predetermined.

As a result, a spark discharge is generated in the ignition electrode 12 while the combustion air having a flow rate corresponding to the normal ignition rotation speed of the combustion fan 10 and the fuel gas having a flow rate corresponding to the ignition rotation speed are supplied to the burner 4. Then, the burner 4 is ignited.

Further, at the start of each combustion operation of the burner 4 after the second time in the on / off combustion control process, the determination result of STEP 7 becomes affirmative. At this time, the control device 30 executes the ignition process of the burner 4 in STEP 9.

In this ignition process, the control device 30 operates the combustion fan 10 at the ignition speed for on-off combustion determined in STEP 5. Further, the control device 30 supplies the fuel gas having a flow rate corresponding to the ignition rotation speed of the combustion fan 10 for on / off combustion to the burner (first burner 4a) for the on / off combustion control process among the burners 4. An igniter (not shown) is operated while controlling the opening of the main valve 7 and the switching valve 9a and the control of the gas amount adjusting valve 8. In this case, the control value of the gas amount adjusting valve 8 corresponding to the flow rate of the fuel gas supplied to the burner 4 is a map or a map according to the ignition rotation speed for on / off combustion of the combustion fan 10 or the required heat amount of the burner 4. It is determined by an arithmetic expression or the like.

As a result, the combustion air having a flow rate corresponding to the ignition rotation speed for on / off combustion of the combustion fan 10 and the fuel gas having a flow rate corresponding to the ignition rotation speed are supplied to the burner 4, and sparks are discharged to the ignition electrode 12. Is generated, and the burner 4 is ignited. The flow rates of the combustion air and the fuel gas supplied to the burner 4 in the ignition process of STEP 9 are smaller than the flow rates of the combustion air and the fuel gas supplied to the burner 4 in the ignition process of STEP 8. Is.

When the determination result of STEP 4 is affirmative (when it is determined that the degree of blockage of the air supply / exhaust flow path is higher than a predetermined threshold value), the control device 30 determines the degree of blockage of the air supply / exhaust flow path in STEP 6. (In the present embodiment, according to the detected value of the fan current as an index value indicating the degree of blockage), the ignition rotation speed obtained by correcting the normal ignition rotation speed of the combustion fan 10 is determined. ..

In this case, the control device 30 increases the fan current so that the corrected ignition speed is higher than the normal ignition speed as the degree of blockage of the air supply / exhaust flow path is higher (the lower the fan current detection value is). The normal ignition speed is corrected according to the detected value of. As the method of the amendment, for example, the method disclosed by the applicant of the present application in JP-A-2017-129313 can be adopted.

Then, the control device 30 further executes the ignition process of the burner 4 in STEP 10. In this ignition process, the control device 30 operates the combustion fan 10 at the corrected ignition speed determined in STEP6. Further, the control device 30 uses a burner for on / off combustion control processing in the burner 4 (fuel gas having the same flow rate as the ignition processing in STEP 8) having a flow rate corresponding to the normal ignition rotation speed of the combustion fan 10. An igniter (not shown) is operated while controlling the opening of the main valve 7 and the switching valve 9a and the control of the gas amount adjusting valve 8 so as to supply the first burner 4a). In this case, the control value of the gas amount adjusting valve 8 corresponding to the flow rate of the fuel gas supplied to the burner 4 is the same as the control value in STEP 8. As a result, while the combustion air and fuel gas having the same flow rate as the ignition process of STEP 8 are supplied to the burner 4, a spark discharge is generated in the ignition electrode 12 and the burner 4 is ignited.

The control device 30 determines whether or not the burner 4 has ignited in STEP 11 based on the output of the flame detection sensor 13 while executing the ignition process in STEP 8 or STEP 9 or STEP 10 as described above. If the determination result of STEP 11 is negative, the control device 30 increases the ignition rotation speed of the combustion fan 10 by a predetermined amount from the current rotation speed in STEP 12, and performs the ignition process of the burner 4. It is executed again, and further, the determination process of STEP 11 is executed. In this case, in STEP 12, the control device 30 controls the gas amount adjusting valve 8 so as to increase the supply amount (flow rate) of the fuel gas to the burner 4 (first burner 4a) by a predetermined amount.

If the ignition of the burner 4 is not detected in the STEP 11 even after the ignition process in the STEP 12 is executed a predetermined number of times, the control device 30 stops the control of the combustion operation of the burner 4 to cause an abnormality. The indicated information is output via the remote controller 40.

When the burner 4 ignites and the judgment result of STEP 11 is affirmative (when the combustion operation of the burner 4 is started by the ignition process of any of STEP 8, 9, 10 and 12), or the judgment result of STEP 1 If is affirmative (when the burner 4 is already in the combustion operation), the control device 30 then in STEP 13, the hot water supply temperature detected by the temperature sensor 25 is only a predetermined value higher than the target hot water supply temperature. The process of determining whether or not the temperature has risen to a temperature higher than the first threshold temperature TH1 set to a high temperature is sequentially executed until the determination result becomes affirmative.

Then, when the determination result of STEP 13 becomes affirmative, next, in STEP 14, the fire extinguishing process of the burner 4 (first burner 4a) is executed, and the combustion fan 10 is rotated at a predetermined low rotation speed for purging the combustion chamber 3a. Driven by a number. In this case, in the fire extinguishing process of the burner 4, the fuel to the first burner 4a is controlled by closing the switching valve 9a (or the main valve 7) corresponding to the first burner 4a that performs the combustion operation in the on / off combustion control process. Cut off the gas supply.

Then, the control device 30 operates the combustion fan 10 at a low rotation speed for purging as described above, and at STEP 15, the hot water supply temperature detected by the temperature sensor 25 becomes a temperature lower than the target hot water supply temperature by a predetermined value. The process of determining whether or not the temperature has dropped to a temperature lower than the set second threshold temperature TH2 is sequentially executed until the determination result becomes affirmative. Further, when the determination result of STEP 15 becomes affirmative, the control device 30 restarts the process from STEP 4.

In the present embodiment, the on / off combustion control process is executed as described above. In this case, when the degree of blockage of the air supply / exhaust flow path is low, the ignition rotation speed of the combustion fan 10 and the supply amount (flow rate) of the fuel gas to the burner 4 in the second and subsequent ignition processes of the burner 4 are the burner 4. It is controlled so as to change according to the required heat quantity (the larger the required heat quantity, the larger the required heat quantity). As a result, it is possible to prevent the hot water supply temperature from overshooting the target hot water supply temperature or the temperature rise to the target hot water supply temperature being too slow. As a result, the hot water supply temperature can be stably maintained at a temperature near the target hot water supply temperature.

Further, in the second and subsequent ignition processes of the burner 4, the required heat amount of the burner 4 is usually small, so that the ignition rotation speed of the combustion fan 10 in the ignition process can be suppressed to a lower rotation speed. As a result, it is possible to suppress the operating noise of the combustion fan 10 in the ignition processing of the burner 4 from the second time onward.

Further, when the degree of blockage of the air supply / exhaust flow path is high, the ignition process in STEP 10 is executed, so that it is possible to increase the certainty that the burner 4 is normally ignited.
If the ignition of the burner 4 is not detected in STEP 11, the ignition process of the burner 4 is executed again after increasing the rotation speed of the combustion fan 10 and the amount of fuel gas supplied to the burner 4. , It is possible to increase the certainty that the burner 4 is normally reignited.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, only a part of the control process of the control device 30 is different from the first embodiment. Therefore, the same matters as those in the first embodiment will be omitted.

In the present embodiment, the on / off combustion control process by the control device 30 is executed as shown in the flowchart of FIG. In this case, in the present embodiment, when the determination result of STEP 4 is positive (when the degree of blockage of the air supply / exhaust flow path is higher than a predetermined threshold value), the control device 30 has STEP 6 and 10 in the first embodiment. Instead of the process of STEP6x, the process of STEP6x is executed, and then the process from STEP7 is executed in the same manner as in the first embodiment.

In STEP 6x, the control device 30 determines the ignition speed for on / off combustion according to the required heat amount of the burner 4 for controlling the temperature of hot water supply and the degree of blockage of the air supply / exhaust flow path. Specifically, the control device 30 determines the reference ignition rotation speed for on-off combustion by the same processing as the processing of STEP 5, and determines the reference ignition rotation speed according to the degree of blockage of the air supply / exhaust flow path (this implementation). In the embodiment, the ignition speed used for the actual control of the combustion fan 10 is determined by correcting (according to the detected value of the fan current). In this case, the higher the degree of blockage of the air supply / exhaust flow path, the higher the correction of the ignition rotation speed is so that the corrected ignition rotation speed becomes higher than the reference ignition rotation speed.

In STEP 6x, even if the ignition rotation speed of the combustion fan 10 is determined by using a map or the like from the required heat amount of the burner 4 and the degree of blockage of the air supply / exhaust flow path (in this embodiment, the detected value of the fan current). good.

The present embodiment is the same as the first embodiment except for the matters described above. According to this embodiment, not only when the degree of blockage of the air supply / exhaust flow path is low, but also when the degree of blockage is high to some extent, the burner 4 at the time of ignition of the burner 4 from the second time onward in the on / off combustion control process. The supply amount (flow rate) of the combustion gas to the burner 4 and the rotation speed of the combustion fan 10 are controlled to the supply amount and the rotation speed corresponding to the required heat amount of the burner 4.

Therefore, the hot water supply temperature can be stably maintained at a temperature near the target hot water supply temperature, and the operating noise of the combustion fan 10 at the time of the second and subsequent ignitions in the on / off combustion control process can be suppressed. Further, when the degree of blockage of the air supply / exhaust flow path is high to some extent, the ignition rotation speed of the combustion fan 10 is set to the rotation speed corrected from the reference ignition rotation speed as described above, so that the air supply / exhaust flow path is blocked. As in the case where the degree is low, the burner 4 can be ignited satisfactorily for the second and subsequent times.

Further, when the ignition of the burner 4 is not detected in the STEP 11, the number of revolutions of the combustion fan 10 and the amount of fuel gas supplied to the burner 4 are increased as in the first embodiment, and then the burner is again used. Since the ignition process of 4 is executed, it is possible to increase the certainty that the burner 4 is normally reignited.

[Other embodiments]
The present invention is not limited to the first embodiment or the second embodiment described above, and other embodiments may be adopted. For example, the combustion device of the present invention is not limited to the hot water supply device that heats the hot water supply water as the target fluid, and may be a combustion device that heats, for example, a heat medium (liquid or gas) for heating as the target fluid. Further, the fuel of the burner 4 is not limited to the fuel gas, and may be a liquid fuel such as kerosene.

1 ... Hot water supply device (combustion device), 4 ... Burner, 5 ... Fuel supply device, 10 ... Combustion fan, 30 ... Control device.

Claims (4)

A burner that generates heat to heat the target fluid by combustion operation, a fuel supply device that supplies fuel to the burner, a combustion fan that supplies combustion air to the burner, and a requirement for temperature control of the target fluid. A combustion device including a fuel supply device and a control device having a function of controlling the combustion fan according to the required heat amount.
The control device is configured to be able to execute an on-off combustion control process, which is a process of controlling the fuel supply device and the combustion fan so as to intermittently perform the combustion operation of the burner, and the on-off combustion control. In the process, at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire of the burner is extinguished, the amount of fuel supplied to the burner and the rotation speed of the combustion fan are used for controlling the temperature control of the target fluid. A combustion device characterized in that the fuel supply device and the combustion fan are controlled so as to be changed according to a required calorific value. In the combustion apparatus according to claim 1,
In the on / off combustion control process, the control device detects the degree of blockage of the air supply / exhaust flow path, which is the flow path of the combustion air or the combustion exhaust gas, while operating the combustion fan at a predetermined rotation speed in the fire extinguishing state of the burner. At least when the degree of blockage is higher than a predetermined value, the number of revolutions of the combustion fan at the time of ignition following the extinguishing state of the burner is the required heat amount for controlling the temperature of the target fluid and the above. A combustion device characterized in that it is configured to control the combustion fan so as to change according to the degree of blockage. In the combustion apparatus according to claim 1,
In the on / off combustion control process, the control device detects the degree of blockage of the air supply / exhaust flow path, which is the flow path of the combustion air or the combustion exhaust gas, while operating the combustion fan at a predetermined rotation speed in the fire extinguishing state of the burner. When the degree of blockage is lower than a predetermined value, the amount of fuel supplied to the burner and the amount of fuel supplied to the burner when the burner is ignited when the combustion operation of the burner is restarted after the burner is extinguished. The fuel supply device and the combustion fan are controlled so as to change the rotation speed of the combustion fan according to the required heat amount for controlling the temperature of the target fluid, and when the degree of blockage is higher than a predetermined value, the burner The fuel supply device is controlled so that the amount of fuel supplied to the burner at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire is extinguished is controlled, and the rotation speed of the combustion fan is set to the above. A combustion device characterized in that the combustion fan is controlled so as to have a rotation speed set according to the degree of blockage. In the combustion apparatus according to any one of claims 1 to 3.
If the ignition of the burner is not detected at the time of ignition of the burner when the combustion operation of the burner is restarted after the fire of the burner is extinguished, the control device supplies fuel to the burner and the combustion fan. A combustion device characterized in that the fuel supply device and the combustion fan are controlled so as to increase the number of revolutions with respect to the time of ignition in which the ignition is not detected.

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