JP6787107B2 - Combustion device - Google Patents

Description

The present invention relates to a combustion device such as a one-can type composite heat source machine.

In Patent Document 1 below, the applicant of the present application detects the combustion flame temperature of the burner with a burner sensor, detects the progress of blockage of the air supply / exhaust flow path based on the combustion flame temperature, and progresses the blockage of the air supply / exhaust flow path. Disclosed is a combustion device that maintains a good air-fuel ratio even if the blockage progresses to some extent by increasing the rotation speed of the blower fan that supplies air to the burner. The burner sensor that directly measures the combustion flame temperature is an expensive component, and improvement has been desired in order to reduce the cost of the combustion device.

On the other hand, in Patent Document 2 below, the inside of the burner case of the combustion device is partitioned by a partition portion, and the inside of the burner case is divided into first and second combustion chambers accommodating the first and second burners, respectively. Combustion air is supplied by a fan from the lower side of these first and second combustion chambers, and first and second heat exchangers for heating hot water are placed above the first and second combustion chambers, respectively. In the arranged combustion apparatus, a pair of communication openings for communicating the first and second combustion chambers with each other are provided on the two plates constituting the partition portion, and at an intermediate position between the pair of communication openings. A technique for arranging an inexpensive temperature sensor such as a thermista or a thermocouple and detecting blockage due to clogging of fins of a heat exchanger based on the detection temperature of the temperature sensor is disclosed.

That is, according to the combustion apparatus described in Patent Document 2, for example, when a blockage occurs on the second heat exchanger side, the amount of combustion gas in the second combustion chamber passing through the communication opening increases. As a result, the temperature detected by the temperature sensor rises. Therefore, it is possible to detect that the second heat exchanger side is blocked based on this temperature rise. When a blockage occurs on the first heat exchanger side, the blockage can be detected by the same principle.

Japanese Patent No. 5018200 Japanese Patent No. 5178656

However, when the first and second heat exchangers are closed at the same time, the difference in internal pressure between the first and second combustion chambers does not occur so much, so that the amount of gas passing through the communication opening also increases so much. However, the temperature detected by the temperature sensor does not rise so much, and blockage detection based on the temperature rise of the detected temperature may not be possible.

Therefore, according to the present invention, even when the air supply / exhaust flow paths of the first and second combustion chambers are blocked at the same time, the temperature sensor is arranged in the opening of the partition portion that partitions the first and second combustion chambers. It is an object of the present invention to provide a combustion apparatus having a control configuration capable of determining blockage based on the detected temperature of.

The present invention has taken the following technical measures in order to achieve the above object.

That is, the combustion apparatus of the present invention relates to a combustion can body, first and second combustion chambers housed in the combustion can body and capable of burning independently of each other, and the first and second combustion chambers. A common fan that supplies combustion air, a partition that partitions the inside of the combustion can into first and second combustion chambers in which the first and second combustion chambers are individually housed, a temperature sensor, and the fan. The partition is provided with an opening for communicating the first and second combustion chambers with each other, and the temperature sensor is used for the combustion gas flowing through the opening. It is provided in the vicinity of the opening so that the detection temperature rises as the amount increases, and the control unit increases the rotation speed of the fan when it determines that the detection temperature of the temperature sensor exceeds a predetermined determination reference temperature. It is configured to perform the fan air volume increasing process and change the determination reference temperature to a relatively small value when it is determined that the drive current value of the fan is less than a predetermined threshold value (claim 1).

According to the combustion apparatus of the present invention, when the blockage of either the first or the second combustion chamber progresses, the internal pressure of the combustion chamber in which the blockage is progressing rises, and the combustion in the combustion chamber The gas passes through the opening of the partition and flows into the other combustion chamber. When the amount of high-temperature combustion gas passing through the opening increases in this way, the detection temperature of the temperature sensor provided near the opening rises, so that the control unit is blocked based on the rise in the detection temperature of the temperature sensor. It can be detected.

On the other hand, even when the first and second combustion chambers are blocked, it is unlikely that the degree of blockage is exactly the same, and both the first and second combustion chambers are in combustion operation. A slight differential pressure is generated even when the pressure is low, and when only one of the combustion chambers is in combustion operation, the combustion chamber is completely sealed even if the other combustion chamber is blocked. Since there is almost no combustion gas, the amount of combustion is reduced as compared with the case where the combustion chamber is not closed, but the combustion gas flows from one combustion chamber to the other combustion chamber through the opening. However, the amount of combustion gas passing through the opening is small for the actual degree of blockage, and the temperature detected by the temperature sensor is also relatively low, so it is necessary to increase the fan air volume. However, the detection temperature of the temperature sensor may be lower than the judgment reference temperature assuming that the blockage is progressing in only one of the combustion chambers.

In such a case, according to the present invention, if it is determined that the drive current value of the fan whose rotation speed is controlled by the control unit is less than a predetermined threshold value, the entire first and second combustion chambers are blocked to some extent. It is judged that it is progressing, the judgment reference temperature is changed to a relatively small value, and if the detection temperature of the temperature sensor is above the judgment reference temperature, which is relatively small, the fan air volume is increased to perform accurate combustion. It will be possible to implement improvements.

The "near the opening" may be inside the opening, or may be outside the opening and facing the opening. Further, the control unit may be configured to execute the fan air volume increasing process based on the detection temperature of the temperature sensor when both the first and second combustion units are in combustion operation. It may be configured to execute when either one of the first combustion part and the second combustion part is in the combustion operation, or when only the first combustion part is in the combustion operation, it is executed but the second combustion is performed. It may be configured not to execute when the part is in the combustion operation, or it is executed when only the second combustion part is in the combustion operation, but not when the first combustion part is in the combustion operation. It may be configured. Further, "increasing the rotation speed of the fan" means that the detection temperature of the temperature sensor is made larger than the normal rotation speed which is lower than the judgment reference temperature, and the normal rotation speed by the control unit. It does not mean that the fan speed is increased or decreased by control. Further, the threshold value of the drive current value is preferably a value set by a function, a relational table, or the like according to the rotation speed of the fan. Further, the control unit may be configured to execute the determination reference temperature change process when both the first and second combustion units are in combustion operation, or the first and second combustion units may be executed. It may be configured to execute when one of the combustion parts is in the combustion operation, or it is executed when only the first combustion part is in the combustion operation, but the second combustion part is in the combustion operation. It may be configured not to execute when it is, or it may be configured to execute when only the second combustion part is in combustion operation but not when the first combustion part is in combustion operation. Good. Further, the above-mentioned "relatively small value" means a value smaller than the value at the normal time when the drive current value is equal to or more than a predetermined threshold value.

In the combustion apparatus of the present invention, the control unit changes the determination reference temperature to the relatively small value until a predetermined time elapses from the start of the combustion operation in the first and / or second combustion units. It may be configured not to be present (claim 2). According to this, the combustion operation is unstable at the initial stage of the start of the combustion operation, but the judgment reference temperature is not changed until a predetermined time (for example, about 1 minute) elapses from the start of the combustion operation. It is possible to prevent the judgment reference temperature from being changed.

Further, the maximum combustion thermal power of the second combustion chamber is smaller than that of the first combustion chamber, and the flow path cross-sectional area of the second combustion chamber is smaller than that of the first combustion chamber so that the amount of air supplied from the fan is smaller. The size is reduced, and the control unit performs the fan air volume increasing process based on the detection temperature of the temperature sensor during the combustion operation of only the second combustion unit, and controls the rotation speed during the combustion operation of the first combustion unit. It may be configured to perform the blockage determination based on the drive current value of the fan (claim 3). According to this, the flow path cross-sectional area of the first combustion chamber is larger than that of the second combustion chamber, and the blockage rate in the first combustion chamber remarkably appears in the change of the drive current value of the fan. During the combustion operation of the combustion chamber, the blockage is determined in the first combustion chamber based on the drive current value of the fan whose rotation speed is controlled so as to reach the target rotation speed, and if the blockage is detected, an abnormality is notified. Alternatively, a process of increasing the target rotation speed of the fan by a certain ratio (for example, 5% increase or 10% increase) can be performed to improve combustion. On the other hand, since the cross-sectional area of the flow path of the second combustion chamber is relatively small, the response to the drive current value of the fan is slow even if the blockage progresses in the second combustion chamber, and the drive current is only the drive current value of the fan. It is difficult to determine whether the decrease in value is due to the progress of blockage or other factors, but according to the present invention, the drive current value of the fan decreases to some extent during the combustion operation of only the second combustion chamber. If it becomes less than the threshold value, the judgment reference temperature is changed to a relatively low value, and if it is judged that the detection temperature of the temperature sensor is equal to or higher than the judgment reference temperature, the fan air volume is increased to increase the cross-sectional area of the flow path. There is still a margin in the degree of closure of the first combustion chamber with a large size, but the degree of closure of the second combustion chamber with a small flow path cross-sectional area is the second when the fan speed increase treatment is required. It can be expected that the combustion improvement in the second combustion part can be expected by accurately detecting the blockage of the combustion chamber and performing the fan air volume increase treatment.

The blockage determination based on the drive current value of the fan and the fan rotation speed increase process based on the blockage determination result are well known in the past, and can be performed by, for example, the control method disclosed in Patent Document 1. Further, the determination based on the drive current value also includes the case where other parameters having a unique relationship with the drive current value, such as the drive power and the drive voltage, are used as control determination parameters.

According to the combustion apparatus of the present invention, even when the air supply / exhaust flow paths of the first and second combustion chambers proceed at the same time, the blockage is detected by the drive current value of the fan and the detection temperature of the temperature sensor provided in the communication opening. By combining with the blockage detection based on the above, the blockage determination based on the detection temperature of the temperature sensor is possible.

It is a front sectional view of the combustion apparatus which concerns on one Embodiment of this invention. It is a main part perspective view which shows the mounting position of the temperature sensor in the combustion apparatus. It is a graph explaining each threshold value set in the control part of the combustion apparatus. It is a time chart at the time of operation of the combustion apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a combustion device 1 according to an embodiment of the present invention, and the combustion device 1 has two systems such as general hot water supply and bath hot water supply (bath reheating hot water supply), or general hot water supply and heating hot water supply. It is configured as an instantaneous gas water heater in the form of a one-can type combined heat source machine capable of supplying hot water, and its basic configuration is, for example, the same as that described in Japanese Patent No. 5781167.

That is, the combustion device 1 includes a combustion can body 2, and the combustion can body 2 is mounted on the burner case 2a, the primary heat exchange case 2b mounted on the burner case 2a, and the primary heat exchange case. It is composed of the secondary heat exchange case 2c. The burner case 2a houses the first and second combustion parts 31 and 32 that can be individually burned, and the primary heat exchange case 2b is above the first and second combustion parts 31 and 32, respectively. The first and second primary heat exchangers 41 and 42 located in the above are housed in, and the first and second primary heat exchangers 41 and 42 located above the first and second primary heat exchangers 41 and 42 are housed in the secondary heat exchange case 2c. The first and second secondary heat exchangers 51 and 52 are housed, and the high-temperature combustion gas generated by the first combustion unit 31 is used to generate heat in the first primary heat exchanger 41, and further, the first heat exchanger is generated. The secondary heat exchanger 51 is configured to sequentially recover latent heat so that the hot water flowing through the heat exchangers 41 and 51 can be heated, and the high temperature generated by the second combustion unit 32 is high. The second primary heat exchanger 42 recovers the sensible heat from the combustion gas, and the second secondary heat exchanger 52 sequentially recovers the latent heat to heat the hot water flowing through the heat exchangers 42 and 52. It is configured as follows.

The internal space of the combustion can body 2 is divided into the first and second combustion chambers C1 and C2 by the partition portion P. The partition portion P partitions the internal space of the secondary heat exchange case 2c from the first partition portion Pa that partitions the internal space of the burner case 2a and the second partition portion Pb that partitions the internal space of the primary heat exchange case 2b. It is composed of a third partition portion Pc, and these first to third partition portions Pa, Pb, and Pc are continuously provided in the vertical direction. Then, the first combustion unit 31, the first primary heat exchanger 41, and the first secondary heat exchanger 51 are housed in the first combustion chamber C1, while the second combustion unit 32, the second. The primary heat exchanger 42 and the second secondary heat exchanger 52 are housed in the second combustion chamber C2.

The configurations of the primary heat exchangers 41 and 42 and the secondary heat exchangers 51 and 52 may be appropriate, but they are the same as those shown in FIGS. 1 and 2 of Japanese Patent No. 5781167. It may be a configuration. That is, each of the primary heat exchangers 41 and 42 is provided with a large number of heat radiating fins 71 and 72 arranged side by side in the paper surface direction in FIG. 1 on the outer periphery of the meandering heat transfer tubes 61 and 62 in a plan view. Further, each of the secondary heat exchangers 51 and 52 is composed of a single heat transfer tube formed in a spiral shape and in multiple stages.

The combustion gas generated by the first combustion unit 31 recovers sensible heat and latent heat when passing through the first primary heat exchanger 41 and the first secondary heat exchanger 51, and then the secondary heat. It is exhausted from an exhaust port (not shown) provided in the exchanger 51. The hot water supplied to the upstream end 51a of the heat transfer tube constituting the first secondary heat exchanger 51 is heated by flowing through the heat transfer tube of the heat exchanger 51 to reach the downstream end 51b, and then reaches the downstream end 51b. It is sent to the heat transfer tube 61 of the primary heat exchanger 41 of No. 1, further heated in the primary heat exchanger 41, and then discharged.

Similarly, the combustion gas generated by the second combustion unit 32 recovers sensible heat and latent heat when passing through the second primary heat exchanger 42 and the second secondary heat exchanger 52, and then recovers sensible heat and latent heat. It is exhausted from an exhaust port (not shown) provided in the secondary heat exchanger 52. The hot water supplied to the upstream end 52a of the heat transfer tube constituting the second secondary heat exchanger 52 is heated by flowing through the heat transfer tube of the heat exchanger 52 to reach the downstream end 52b, and then reaches the downstream end 52b. It is sent to the heat transfer tube 62 of the primary heat exchanger 42 of No. 2, and after being further heated in the primary heat exchanger 42, hot water is discharged.

The first and second combustion units 31 and 32 are configured by arranging a plurality of burners 8 (combustion pipes) side by side in a side-by-side manner. The configuration of each burner 8 may be appropriate, but typically, as shown by a virtual line in FIG. 2, it is flat as a whole and has a fuel gas introduction port 8a at the lower end of one end in the longitudinal direction. However, it has an upper opening-shaped flame hole 8b at the upper part. Further, as shown in FIG. 2 of Japanese Patent No. 5781167, the fuel gas is injected and supplied from the fuel gas supply nozzle provided on the side of the burner case 2a toward the fuel gas introduction port 8a. It has become. Further, a part of the combustion air (primary air) supplied from the fan 9 provided in the lower part of the combustion can body 2 is also introduced into the fuel gas introduction port 8a, and is burned with the fuel gas introduced in the burner 8. The mixed gas of the working air burns on the flame hole 8b. The burner 8 may be provided with a combustion air introduction port separately from the fuel gas introduction port 8a.

A straightening vane 10 having a plurality of air flow holes 10a is provided below the burner 8, and a part of the combustion air (secondary air) supplied from the fan 9 into the burner case 2a is air flowed. It passes through the hole 10a and is supplied to the installation areas of the plurality of burners 8. A heat shield plate 12 is provided inside the side wall portion 11 of the burner case 2a, and a part of combustion air is also supplied to the gap between the heat shield plate 12 and the side wall portion 11, thereby providing a side wall. It is prevented that the part 11 is heated to an abnormally high temperature.

The first combustion unit 31 is for general hot water supply, and has a larger number of burners 8 than the second combustion unit 32 for bath hot water supply or heating hot water supply, and has a high maximum combustion capacity. Therefore, the first combustion chamber C1 has a larger flow path cross-sectional area and volume than the second combustion chamber C2, and the supply ratio of combustion air from the fan 9 is also large.

The partition portion Pa in the burner case 2a is composed of a plate-shaped partition body 13 and a ventilation guide plate 14, and the partition body 13 and the guide plate 14 are made of stainless steel or other material having excellent heat resistance. There is. The partition main body 13 stands up from the height of the upper surface of the straightening vane 10 or its vicinity to the height of the uppermost portion in the burner case 2a or its vicinity. The guide plate 14 is attached to the side surface of the upper region of the partition main body 13 on the second combustion chamber C2 side from a position slightly lower than the flame hole surface of the burner 8, and the partition main body 13 and the guide plate. A lower opening-shaped gap 15 is formed between the 14 and the partition main body 13 and the guide plate 14 is cooled by a part of combustion air flowing through the gap.

Further, in the present embodiment, as a means for detecting exhaust blockage in the downstream region in the combustion gas flow direction of the second combustion chamber C2, particularly exhaust blockage due to fin clogging of the primary heat exchanger 42, the first partition portion Pa A temperature sensor S composed of a temperature sensitive element such as a thermistor is formed in the partition main body 13 and the guide plate 14 constituting the above, respectively, so that the communication openings 13a and 14a face each other. Are arranged. The communication openings 13a and 14a are located higher than the flame hole surface of the burner 8, and the first and second combustion chambers C1 and C2 communicate with each other through the communication openings 13a and 14a and the gap 15. doing.

As shown in FIG. 2, the communication opening 14a of the guide plate 14 is formed by cutting out a part of one side edge of the guide plate 14. The communication opening 13a of the partition main body 13 is formed in a round hole shape, for example, and its opening area is smaller than that of the communication opening 14a of the guide plate 14.

The temperature detection portion at the tip of the temperature sensor S is located in the second combustion chamber C2, and is arranged close to the temperature sensor S facing the opening regions of the communication openings 13a and 14a. Preferably, the temperature detection portion of the temperature sensor S is arranged so as to overlap without protruding from both the opening regions of the communication openings 13a and 14a. With this configuration, when the second combustion unit 32 burns while the second primary heat exchanger 42 is blocked due to fin clogging, the internal pressure of the second combustion chamber C2 rises and the second combustion occurs. The amount of high-temperature combustion gas flowing through the communication openings 13a and 14a increases from the inside of the chamber C2 to the inside of the first combustion chamber C1, and the temperature sensors S arranged in the vicinity facing the communication openings 13a and 14a. Since high-temperature combustion gas flows around the combustion chamber, the detection temperature of the temperature sensor S rises as the blockage rate in the second combustion chamber C2 increases. On the other hand, even when only the first combustion chamber C1 is engaged in combustion while the first combustion chamber C1 is being blocked, the opening for communication from the first combustion chamber C1 to the second combustion chamber C2. The high-temperature combustion gas flows through the 13a and 14a, but the high-temperature combustion gas passes through the communication opening 14a due to the presence of the gap 15 and the large communication opening 14a of the guide plate 14. Since the combustion is diffused in a relatively wide range, the temperature rise of the temperature sensor S when only the first combustion chamber 31 is in the combustion operation can be suppressed.

The gap 15 between the partition main body 13 of the partition portion Pa and the guide plate 14 is an air flow path through which air flows upward. Such air flow essentially prevents the combustion gas in the second combustion chamber C2 from passing through the communication opening 14a and flowing into the gap 15. On the other hand, since the communication opening 14a of the guide plate 14 is relatively large and is configured by notching the side edge portion, the combustion gas flows into the gap 15 due to the above-mentioned air flow. Is alleviated, and the combustion gas of the second combustion chamber C2 can be smoothly flowed into the gap 15. Further, although the opening area of the communication opening 13a of the partition main body 13 is relatively small, the internal pressures of the gap 15 and the second combustion chamber C2 are basically the same, and are located in the downstream region of the second combustion chamber C2. When the exhaust blockage occurs, the internal pressure of the gap 15 also becomes higher than the internal pressure of the first combustion chamber C1. Therefore, even if the opening area of the communication opening 13a is small, it is possible to generate a flow of combustion gas from the gap 15 into the first combustion chamber C1, and by reducing the opening area, exhaust blockage occurs. It is possible to reduce the amount of combustion gas leaked when this is not the case.

Further, the combustion device 1 of the present embodiment includes a control unit 16 that controls the rotation speed of the fan 9, controls the operation of other parts, and executes data processing. The rotation speed control of the fan 9 is conventionally known as described in Patent Document 1 and the like, and the target rotation speed is calculated by calculation based on various conditions, and the fan 9 is set to the target rotation speed. It is for feedback control.

In particular, the control unit 16 of the present embodiment determines whether or not there is an exhaust blockage in the downstream region of the second combustion chamber C2 based on the temperature detected by the temperature sensor S, and determines whether or not the exhaust gas is blocked based on the detected temperature of the temperature sensor S. Combustion improvement is attempted by increasing the fan air volume when exhaust blockage is detected in the second combustion chamber C2 by incrementally correcting the target rotation speed calculated by conditions other than the presence or absence (for example, 5%). It is configured as. That is, the blockage determination reference temperature (determination reference temperature) for determining exhaust blockage is preset in the control unit 16 according to the combustion capacity of the second combustion unit 32, the structure of the second combustion chamber C2, and the like. It is stored, and when the detection temperature of the temperature sensor S exceeds the blockage determination reference temperature (for example, 250 ° C.), it is determined that exhaust blockage has occurred in the downstream region of the second combustion chamber C2, and the fan air volume increase process is performed. Is configured to do.

The control unit 16 is configured to determine the exhaust blockage in the downstream region of the first combustion chamber C1 based on the drive current value of the fan 9. That is, the threshold value for determining the exhaust blockage is set in advance according to the actual rotation speed of the fan 9 as shown by the blockage determination threshold line in FIG. 3, and the drive current value of the fan 9 is smaller than the above threshold value. Then, it is configured to determine that the exhaust blockage has occurred in the downstream region of the first combustion chamber C1. The amount of air blown from the fan 9 to the first combustion chamber C1 is larger than the amount of air blown to the second combustion chamber C2, and when exhaust blockage occurs in the downstream region of the first combustion chamber C1, the fan 9 Since the amount of air blown into the entire burner case 2a is greatly reduced, it is possible to accurately determine the presence or absence of exhaust blockage in the downstream region of the first combustion chamber C1 based on the change in the drive current value of the fan 9. is there. Then, when the control unit 16 determines that an exhaust blockage has occurred in the downstream region of the first combustion chamber C1, it performs a notification process or an emergency stop process to that effect, or performs a fan 9 for improving combustion. It is configured to perform fan air volume increase processing that increases the target rotation speed of the above by a predetermined ratio.

The fan 9 has a built-in motor (not shown), and the drive current value of the fan 9 is the drive current value of the motor. Further, the control unit 16 to the fan 9 are provided with a drive current value detecting means and an actual rotation speed detecting means for detecting the drive current value and the actual rotation speed of the fan 9. The configuration of these detection means may be any conventionally known appropriate one. Further, the FF line shown in FIG. 3 shows the relationship between the actual rotation speed and the drive current value during feedforward control of the fan 9, and the reference temperature change threshold line is blocked by the detection temperature of the temperature sensor S described later. It is a threshold value for changing the judgment reference temperature.

On the other hand, the amount of change in the drive current value of the fan 9 when an exhaust blockage occurs in the downstream region of the second combustion chamber C2 is small, and the downstream region of the second combustion chamber C2 is based only on the change in the drive current value. It is difficult to determine the presence or absence of exhaust blockage. Therefore, in the present embodiment, as described above, the control unit 16 is configured to determine the exhaust blockage in the downstream region of the second combustion chamber C2 based on the temperature detected by the temperature sensor S. It should be noted that the second combustion unit 32 can change the combustion thermal power, and only a state in which all the burners 8 constituting the second combustion unit 32 are combusted and a part of the burners 8 near the partition portion P are operated. It is possible to switch to a partial combustion state in which the combustion operation is performed.

In the state where the fan 9 and the second combustion unit 32 are being driven, for example, when the fins 72 of the primary heat exchanger 42 are clogged with each other and the exhaust is blocked, the inside of the second combustion chamber C2 The pressure in the second combustion chamber C2 rises from that in the unclosed state, and a part of the combustion gas in the second combustion chamber C2 passes through the communication openings 13a and 14a and flows into the first combustion chamber C1 side, thereby causing a high temperature. A gas flow of combustion gas is generated around the temperature sensor S. As a result, when the detection temperature of the temperature sensor S rises and exceeds a predetermined blockage determination reference temperature (for example, 250 ° C.), a fan air volume increasing process for increasing the rotation speed of the fan 9 is performed in order to try to improve combustion. .. If the blockage is such that the combustion gas can flow due to the increase in the fan air volume, the combustion gas can normally flow to the downstream region of the second combustion chamber C2 by the fan air volume increase treatment, and the communication opening 13a, Since the amount of combustion gas passing through 14a decreases, the temperature detected by the temperature sensor S also gradually decreases.

The fan air volume increasing process can be performed a plurality of times. For example, when the combustion improvement correction factor for the intermediate target rotation speed calculated based on the conditions other than the blockage determination result based on the detection temperature of the temperature sensor S is set at the start of combustion. Set to 100%, increase the combustion improvement correction rate by 5% each time the fan air volume increase processing is performed, and control the fan speed so that the final target rotation speed is obtained by multiplying the intermediate target rotation speed by the combustion improvement correction rate. can do. Preferably, the fan air volume increasing process is performed a predetermined number of times, for example, twice, and if the detection temperature of the temperature sensor S does not decrease even after the fan air volume increasing process a predetermined number of times, an abnormality process such as an abnormality notification or an emergency stop is performed. Can be done. Further, since the combustion state is unstable at the initial stage of the start of the combustion operation, the fan air volume increasing process is performed as a combustion improvement prohibition period until a predetermined time (for example, about 1 minute) elapses from the start of the combustion operation of the second combustion unit 32. You can avoid doing it. Further, since it takes a certain amount of time for the temperature sensor S to respond to the detected temperature after the fan air volume increasing process, a predetermined time (for example, about 1 minute) has elapsed since the fan air volume increasing process was performed once. Even so, it is possible to prevent the fan air volume increase process from being performed as a combustion improvement prohibition period.

Further, the initial correction factor of the fan rotation speed is calculated based on the history of the fan air volume increase processing performed from the start of the combustion operation of the second combustion unit 32 to the end of the combustion operation (stop of the hot water supply operation), and the next time. At the time of combustion operation, the rotation speed of the fan 9 after the fan air volume increase processing can be controlled so that the final target rotation speed obtained by the intermediate target rotation speed × (combustion improvement correction factor × initial correction factor) is obtained. In this case, it is preferable to set the upper limit of (combustion improvement correction factor × initial correction factor) so that the target rotation speed is not excessively corrected, and for example, the upper limit can be set to 110%.

It is preferable that the initial correction factor is stored in memory even after the hot water supply operation is stopped, and the update process is performed each time the hot water supply operation is stopped. On the other hand, the combustion improvement correction factor is preferably reset to 100% after the hot water supply operation is stopped.

Further, the control unit 16 of the present embodiment has a predetermined reference temperature change threshold value located between the blockage determination threshold line and the FF line, although the drive current value of the fan 9 has not decreased to the blockage determination threshold line. When it is determined by the line (see FIG. 3) that the threshold value is less than the threshold value determined for each actual rotation speed of the fan 9, the blockage determination reference temperature is changed to a relatively small value (for example, 200 ° C.) as shown in FIG. It is configured as. This is because the blockage is progressing in the downstream regions of both the first and second combustion chambers C1 and C2, but the degree of blockage in the downstream region of the first combustion chamber C1 still has a margin, so the drive current. The value has not decreased to the blockage determination threshold line, while the degree of blockage in the downstream region of the second combustion chamber C2 has progressed to the extent that fan air volume increase processing is required, but the first Since the degree of closure in the combustion chamber C1 has advanced to some extent, the amount of combustion gas flowing from the second combustion chamber C2 to the first combustion chamber C1 through the communication openings 13a and 14a does not increase so much. This is to cope with the fact that the fan air volume increasing process for improving the combustion of the second combustion chamber 32 described above is not performed.

According to the combustion apparatus 1 of the present embodiment, as shown in FIG. 4, the detection temperature of the temperature sensor S does not rise to 250 ° C., which is the initial blockage determination reference temperature, but rises to about 230 ° C. When it is determined that the drive current value of the fan 9 has dropped to the reference temperature change threshold line, the blockage determination reference temperature is set to 200 ° C., whereby the detection temperature of the temperature sensor S is higher than the blockage determination reference temperature. Therefore, the above-mentioned fan air volume increasing process is executed. If the combustion is improved by the fan air volume increasing process, the temperature detected by the temperature sensor S will decrease as shown in FIG. On the other hand, if the detection temperature of the temperature sensor S does not decrease even after one fan air volume increase process, the second fan air volume increase process is performed as described above.

The reference temperature change threshold line may be a blockage determination threshold line incremented by a certain percentage (α%), or may be set and stored in the control unit 16 in advance separately from the blockage determination threshold line. Further, when the FF line is stored in the control unit 16, the value may be set to a certain percentage lower than the FF line.

To prevent erroneous detection, when it is detected that the drive current value of the fan 9 is continuously below the reference temperature change threshold line for a predetermined time (3 seconds in the illustrated example), the drive current value is less than the predetermined threshold value. The blockage determination reference temperature is changed by determining that the temperature has been changed, and the above-mentioned combustion improvement prohibition period can be set from 3 seconds to 60 seconds after the change of the blockage determination reference temperature.

After the blockage determination reference temperature is lowered to 200 ° C., the low blockage determination reference temperature can be maintained until the combustion operation is stopped, and the temperature can be reset to 250 ° C. when the combustion operation is stopped.

The present invention is not limited to the above embodiment, and the design can be changed as appropriate. For example, the temperature sensor S can be arranged between the two plates constituting the partition portion as described in Patent Document 2, and in this case, even during the combustion operation of the first combustion portion C1. It is also possible to carry out a fan air volume increase process based on the detection temperature of the temperature sensor S and a blockage determination reference temperature change process.

C1 First combustion chamber C2 Second combustion chamber S Temperature sensor P Partition 1 Combustion device 2 Combustion can body 31 First combustion chamber 32 Second combustion chamber 9 Fan 13a Opening 14a Opening 16 Control

Claims (3)

A common fan that supplies combustion air to the combustion can body, the first and second combustion chambers housed in the combustion can body and capable of burning independently of each other, and the first and second combustion chambers. A partition unit that partitions the inside of the combustion can into first and second combustion chambers in which the first and second combustion units are individually housed, a temperature sensor, and a control unit that controls the rotation speed of the fan motor. With and
The partition portion is provided with an opening for communicating the first and second combustion chambers with each other, and the temperature sensor has the opening so that the detection temperature rises as the amount of combustion gas flowing through the opening increases. It is provided near the part
When the control unit determines that the detection temperature of the temperature sensor is equal to or higher than a predetermined determination reference temperature, the control unit performs a fan air volume increasing process for increasing the rotation speed of the fan, and the drive current value of the fan is less than a predetermined threshold value. A combustion device configured to change the determination reference temperature to a relatively small value when it is determined that the temperature has been increased. In the combustion apparatus according to claim 1, the control unit changes the determination reference temperature to the relatively small value until a predetermined time elapses from the start of the combustion operation in the first and / or second combustion units. A combustion device characterized in that it is configured not to perform. In the combustion apparatus according to claim 1 or 2, the second combustion chamber has a smaller maximum combustion thermal power than the first combustion chamber, and the second combustion chamber supplies air from the fan more than the first combustion chamber. The cross-sectional area of the flow path is reduced so that the amount is small, and the control unit performs the fan air volume increasing process based on the detection temperature of the temperature sensor during the combustion operation of only the second combustion unit, and the first A combustion apparatus characterized in that during a combustion operation of a combustion chamber, a blockage determination is made based on a drive current value of the fan whose rotation speed is controlled.

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