JP6316150B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus having a function of detecting incomplete combustion and stopping combustion.

  For example, in a forced exhaust type combustion apparatus installed indoors, when leakage of combustion exhaust gas from the exhaust passage occurs, the indoor oxygen concentration gradually decreases due to the outflow of combustion exhaust gas. As a result, due to the lack of oxygen in the combustion air supplied to the burner, the burner becomes incompletely combusted and the concentration of CO (carbon monoxide) in the combustion exhaust gas increases.

  Therefore, a combustion apparatus is known in which a CO sensor is provided in the exhaust passage of the burner to monitor the CO concentration in the combustion exhaust gas during burner combustion (see, for example, Patent Document 1). In the combustion apparatus described in Patent Literature 1, the CO concentration detected by the CO sensor is compared with a determination value, and the burner is extinguished when the state where the CO concentration is equal to or higher than the determination value continues for a certain time or longer. I am doing so.

JP-A-7-103473

  According to the combustion apparatus described in Patent Document 1, it is possible to prevent incomplete combustion of the burner from continuing by detecting incomplete combustion of the burner by extinguishing the burner due to an increase in CO concentration in the combustion exhaust gas. I am trying.

  However, the inventor of the present application supplies combustion air to a plurality of burners by a single fan, and exhausts exhaust gas from each burner through a single exhaust passage. It has been found that it may be difficult to detect incomplete combustion of the burner by the CO sensor provided in the above.

  Accordingly, the present invention provides an incomplete combustion of a burner in a combustion apparatus configured to supply combustion air to a plurality of burners with a single fan and to discharge the combustion exhaust gas of each burner through a single exhaust passage. The purpose is to improve the detection accuracy of.

The present invention has been made to achieve the above object,
A plurality of burners including at least a first burner and a second burner having a maximum combustion amount smaller than that of the first burner;
A single fan for supplying combustion air to the plurality of burners;
A single exhaust passage through which the combustion exhaust gas of the plurality of burners flows;
A CO sensor provided in the exhaust passage;
A combustion control unit that controls the rotational speed of the fan so that combustion air corresponding to the amount of combustion is supplied to the burning burner when at least one of the plurality of burners is burning. When,
When at least one of the plurality of burners is burning, it is detected by the CO sensor except for a detection prohibition period from when the burning burner is ignited until a first predetermined time elapses. An improvement of a combustion apparatus provided with an incomplete combustion countermeasure unit that monitors whether or not a first determination condition for incomplete combustion based on CO concentration is satisfied and extinguishes a burner during combustion when the first determination condition is satisfied About.

  The incomplete combustion countermeasure unit monitors whether the second determination condition for incomplete combustion based on the CO concentration detected by the CO sensor is satisfied when only the second burner is in combustion, When the second determination condition is satisfied, the second burner is extinguished once and then re-ignited, and from the time of the re-ignition, the presence or absence of the third determination condition based on the CO concentration detected by the CO sensor is monitored. When the third determination condition is satisfied, the second burner is extinguished.

  In the combustion apparatus of the present invention, combustion air is supplied to the plurality of burners by the single fan, and combustion exhaust gas from each burner flows into the single exhaust passage and is discharged. It is the composition which becomes.

  According to this configuration, when the combustion device is installed indoors, the combustion exhaust gas discharged from the plurality of burners is discharged from the exhaust passage to the outside, so that the combustion exhaust gas basically flows into the room. There is nothing. However, it is conceivable that a part of the combustion exhaust gas flows out indoors due to a defect in the exhaust passage. In this case, the indoor oxygen concentration is reduced by the combustion exhaust gas flowing out indoors. As a result, the oxygen concentration in the combustion air taken in from the indoor by the fan and supplied to the fan is lowered, resulting in a situation where incomplete combustion of the burner occurs.

  The rotation speed of the fan is controlled by the combustion control unit so that combustion air corresponding to the amount of combustion is supplied to the burning burner, so that the first burner is in the fire extinguishing state. Thus, when the second burner is in combustion, the rotational speed of the fan is determined in consideration of the flow rate of air flowing to the first burner side.

  In this case, even if incomplete combustion of the second burner occurs, the combustion exhaust gas of the second burner is diluted by the air flowing through the first burner side, so the CO concentration in the combustion exhaust gas of the second burner And the detection of incomplete combustion of the second burner based on the CO concentration becomes difficult.

  Therefore, when only the second burner is in combustion, the incomplete combustion countermeasure unit monitors whether the second determination condition for incomplete combustion based on the CO concentration is satisfied. In this case, the second determination condition can be set to a condition in which incomplete combustion of the second burner is easily detected in accordance with a situation where only the second burner is in combustion.

  When the second determination condition is satisfied, the incomplete combustion countermeasure unit extinguishes the second burner and then reignites, and whether or not the third determination condition based on the CO concentration is satisfied from the time of reignition. To monitor. As described above, when the second burner is extinguished and then reignited, the CO concentration in the combustion exhaust gas is raised due to the unburned gas being mixed into the combustion exhaust gas of the second burner. As a result, since the third determination condition is easily satisfied, the burner can be extinguished by accurately detecting that the second burner is incompletely combusted.

  In addition, the incomplete combustion countermeasure unit monitors whether or not the second determination condition is satisfied when only the second burner is in combustion, and after only the second burner is in a combustion state. It starts when the second predetermined time has elapsed.

  According to this configuration, the influence of the combustion exhaust gas of the burners other than the second burner is eliminated by waiting for the second predetermined time or more to elapse after only the two burners are in a combustion state. Thus, the incomplete combustion of the second burner can be detected with higher accuracy.

The block diagram of a heat-source apparatus. The flowchart of CO concentration monitoring processing. Explanatory drawing of the change of CO concentration at the time of burner ignition.

  An example of an embodiment of the present invention will be described with reference to FIGS.

  Referring to FIG. 1, a heat source device 1 (corresponding to a combustion device of the present invention) of the present embodiment has a hot water supply function for heating water supplied from a water supply pipe 35 and discharging the hot water from a hot water supply pipe 36, and heating forward. This is a composite type heat source device having a heating function of circulating hot water to a heating terminal (floor heater, hot air heater, etc.) not shown via a pipe 45 and a heating return pipe 46.

  The heat source device 1 includes a can body 20 that forms a combustion chamber in a housing 10. In the can body 20, it is connected to a water supply pipe 35 and a hot water supply pipe 36 to heat the water flowing inside, and is connected to a heating forward pipe 45 and a heating return pipe 46 to flow inside. A heating heat exchanger 40 for heating water is provided.

  A hot water supply burner 31 (corresponding to the first burner of the present invention) is provided below the hot water supply heat exchanger 30, and a heating burner 41 (corresponding to the second burner of the present invention) is provided below the heating heat exchanger 40. It has been. The maximum combustion amount (for example, 14 kW) of the heating burner 41 is set smaller than the maximum combustion amount (for example, 30 kW) of the hot water supply burner 31.

  The hot water supply heat exchanger 30 includes a hot water main heat exchanger 30a that mainly absorbs sensible heat from the combustion exhaust gas of the hot water burner 31, and a hot water sub heat exchanger 30b that mainly absorbs latent heat from the combustion exhaust gas of the hot water burner 31. It is configured. The heating heat exchanger 40 includes a heating main heat exchanger 40a that mainly absorbs sensible heat from the combustion exhaust gas of the heating burner 41, and a heating sub heat exchanger 40b that mainly absorbs latent heat from the combustion exhaust gas of the heating burner 41. It is comprised by.

  The hot water supply burner 31 includes a large burner 31a, a middle burner 31b, and a small burner 31c. The heating burner 41 includes a large burner 41a and a small burner 41b.

  The heat source device 1 includes a hot water supply gas solenoid valve 32 that switches between supply and shutoff of fuel gas to the large burner 31a, a hot water supply gas solenoid valve 33 that switches between supply and shutoff of fuel gas to the middle burner 31b, and a small burner 31c. Hot water supply solenoid valve 34 for switching between supply and shutoff of fuel gas, heating gas solenoid valve 42 for switching between supply and shutoff of fuel gas to the large burner 41a, and heating for switching supply and shutoff of fuel gas to the small burner 41b Gas proportional valve 51 for adjusting the supply flow rate of the fuel gas to the gas solenoid valve 43, the hot water supply burner 31 and the heating burner 41, and the original gas solenoid valve 52 for switching the supply and shutoff of the fuel gas to the hot water supply burner 31 and the heating burner 41. , A fan 50 that supplies combustion air to the hot water supply burner 31 and the heating burner 41, and a circulation pump that circulates the hot water in the heating circuit (the heating forward pipe 45 and the heating return pipe 46). It is equipped with a 48.

  A collective exhaust pipe 11 (corresponding to an exhaust passage of the present invention) is connected to the upper portion of the can body 20, and combustion exhaust gas from the hot water supply burner 31 and the heating burner 41 is discharged to the outside via the collective exhaust pipe 11. Is done. An air supply pipe 13 is connected to the upper portion of the housing 10. By the operation of the fan 50, the air flowing from the outside through the air supply pipe 13 and the air flowing from the indoor through the opening of the housing 10 are supplied to the hot water supply burner 31 and the heating burner 41 as combustion air. The With this configuration, the heat source device 1 is a forced exhaust type (FE: Forced Exhaust type).

  A CO sensor 12 that detects the CO concentration is provided at the inlet of the collective exhaust pipe 11. The hot water supply pipe 36 is provided with a hot water supply temperature sensor 37 for detecting the temperature of hot water discharged from the hot water supply pipe 36, and the heating forward pipe 45 is provided with hot water supplied from the heating forward pipe 45 to a heating terminal (not shown). A heating temperature sensor 47 for detecting the temperature is provided.

  Furthermore, the heat source device 1 is provided with a controller 60 that controls the overall operation of the heat source device 1 and a remote controller 70 for remotely operating the heat source device 1. The controller 60 is an electronic circuit unit including a CPU, a memory, an input / output interface, and the like (not shown). The controller 60 functions as the combustion control unit 61 and the incomplete combustion countermeasure unit 62 by the CPU executing a control program for the heat source device 1 held in the memory.

  The controller 60 receives temperature detection signals from the hot water temperature sensor 37 and the heating temperature sensor 47 and a CO concentration detection signal from the CO sensor 12. Further, the hot water supply gas solenoid valves 32, 33, 34, the heating gas solenoid valves 42, 43, the original gas solenoid valve 52, the gas proportional valve 51, the fan 50, and the circulation pump 48 are operated by a control signal output from the controller 60. Is controlled.

  The combustion control unit 61 controls the original gas solenoid valve 52, the hot water supply gas solenoid valves 32, 33, and 34 so that the temperature of the hot water supplied from the hot water supply pipe 36 becomes a set temperature (set by the remote controller 70). The operation of the valve 51 is controlled to adjust the supply flow rate of the fuel gas to the hot water supply burner 31, and the rotation speed of the fan 50 is controlled to adjust the supply flow rate of the combustion air to the hot water supply burner 31. A hot water supply operation for controlling the combustion amount of the burner 31 is executed.

  The combustion control unit 61 controls the operation of the original gas solenoid valve 52, the heating gas solenoid valves 42 and 43, and the gas proportional valve 51 so that hot water having a predetermined temperature and flow rate is supplied from the heating forward pipe 45. The fuel gas supply flow rate to the heating burner 41 is adjusted, the rotational speed of the fan 50 is controlled to adjust the combustion air supply flow rate to the heating burner 41, and the combustion amount of the heating burner 41 is controlled. In addition, the heating operation for controlling the operation of the circulation pump 48 is executed.

  The incomplete combustion countermeasure unit 62 monitors the CO concentration in the combustion exhaust gas detected by the CO sensor 12 when at least one of the hot water supply burner 31 and the heating burner 41 is in combustion, and burner (hot water supply burner). 31, the process which detects the incomplete combustion of the heating burner 41) is performed. Hereinafter, the processing by the incomplete combustion countermeasure unit 62 will be described according to the flowchart shown in FIG.

  When the power supply to the heat source device 1 is started, the controller 60 is activated, and the operation of the operation switch (not shown) provided in the remote controller 70 causes the heat source device 1 to change from the standby mode to the operation mode (hot water supply operation and heating operation). Can be executed). In the operation mode, a hot water supply operation and a heating operation are executed according to the operation of the remote controller 70.

  When the operation condition of the hot water supply operation or the heating operation (start of water supply to the heat source device 1 by opening the hot water tap, instruction to start heating by operating the remote controller 70, etc.) is established, the process proceeds to STEP1, and the combustion control unit 61 Accordingly, the ignition process of the hot water supply burner 31 or the heating burner 41 is performed.

  In STEP 2, the incomplete combustion countermeasure unit 62 waits for 10 seconds (corresponding to the first predetermined time of the present invention) to elapse from STEP 1 (ignition process start time) and proceeds to STEP 3. Note that the period from when the ignition process is performed until 10 seconds elapses corresponds to the detection inhibition period of the present invention. During this 10-second detection prohibition period, the CO concentration detected by the CO sensor 12 increases due to discharge of unburned gas and the like for a while after the ignition process is started. It is set to prohibit detection of combustion and prevent erroneous detection of incomplete combustion.

In STEP 3, the incomplete combustion countermeasure unit 62 determines whether any of the following determination conditions (1a) to (4a) (corresponding to the first determination condition for incomplete combustion of the present invention) is satisfied.
(1a) The state of 2000 ppm <CO concentration continues for 5 seconds or more.
(2a) The state of 1300 ppm <CO concentration continues for 20 seconds or more.
(3a) 800ppm <CO concentration continues for more than 40 seconds
(4a) The state of 600 ppm <CO concentration continues for 200 seconds or more.

  If at least one of the determination conditions (1a) to (4a) is satisfied and it can be determined that incomplete combustion of the hot water supply burner 31 or the heating burner 41 has occurred, the process branches to STEP 20, and The complete combustion countermeasure unit 62 extinguishes the burning burner of the hot water supply burner 31 and the heating burner 41 and stops the operation of the heat source device 1.

  At this time, the incomplete combustion countermeasure unit 62 displays an error on the display unit of the remote controller 70 indicating that incomplete combustion has occurred. Thus, by stopping the combustion of the hot water supply burner 31 or the heating burner 41 in which incomplete combustion has occurred, the incomplete combustion of the heating burner 41 is continued, and the indoor oxygen concentration is prevented from decreasing. be able to.

  On the other hand, when none of the determination conditions (1a) to (4a) is satisfied, the process proceeds to STEP4. STEP4 to STEP9 and STEP30 are processes for dealing with incomplete combustion of the heating burner 41 during the heating single operation (when only the heating operation is executed and the hot water supply operation is not executed).

  Here, at the time of heating independent operation, referring to FIG. 1, the air supplied from fan 50 flows to both hot water supply burner 31 and heating burner 41. The air supplied to the heating burner 41 is used for combustion, but the air supplied to the hot water supply burner 31 flows out to the collective exhaust pipe 11 without being used for combustion.

  In this case, the combustion exhaust gas from the heating burner 41 is diluted by mixing with the air flowing through the hot water supply burner 31. Therefore, even if incomplete combustion occurs in the heating burner 41, the CO concentration detected by the CO sensor 12 Becomes difficult to rise.

  Therefore, during the heating independent operation, the incomplete combustion countermeasure unit 62 performs the processing according to STEP4 to STEP9 and STEP30 separately from the processing based on the first determination conditions (1a) to (4a) in STEP3 described above, thereby heating the burner. 41 incomplete combustion is dealt with.

  In STEP4, the incomplete combustion countermeasure unit 62 determines whether or not the heating independent operation is continued for 10 seconds (corresponding to the second predetermined time of the present invention) or more. And when heating independent operation is continuing for 10 seconds or more, it progresses to STEP6, and when heating independent operation is not continuing for 10 seconds or more, it returns to STEP3.

  Here, immediately after switching from the state in which both the hot water supply operation and the heating operation are performed to the heating single operation, the combustion exhaust gas of the hot water supply burner 31 remains in the vicinity of the collective exhaust pipe 11. It is difficult to accurately detect the CO concentration in the inside.

  Therefore, only when heating independent operation is continued for 10 seconds or more in STEP 4, the effect of combustion exhaust gas of the hot water supply burner 31 is eliminated by performing the processing of STEP 5 or less, and incomplete combustion of the heating burner 41 is performed. Is detected.

  In STEP 5, the incomplete combustion countermeasure unit 62 determines whether or not the state of 300 ppm <CO concentration continues for 10 seconds or longer (corresponding to the second determination condition for incomplete combustion of the present invention). Then, when the second determination condition is satisfied and there is a possibility that incomplete combustion of the heating burner 41 has occurred, the process proceeds to STEP 6, and when the second determination condition is not satisfied, the process returns to STEP 3.

  Here, the second determination condition of STEP 5 is set to a level that is established in a CO concentration environment lower than the first determination conditions (1a) to (4a). This facilitates detection of incomplete combustion of the heating burner 41 during the single heating operation in which the combustion exhaust gas of the heating burner 41 is diluted by the air flowing on the hot water supply burner 31 side.

In STEP 6, the incomplete combustion countermeasure unit 62 extinguishes the heating burner 41. In subsequent STEP 7, the incomplete combustion countermeasure unit 62 reignites the heating burner 41. Then, in the next STEP 8, the incomplete combustion countermeasure unit 62 determines whether any of the following determination conditions (corresponding to the third determination condition for incomplete combustion of the present invention) is satisfied (1b) to (4b). Judging.
(1b) The state of 2000 ppm <CO concentration continues for 5 seconds or more.
(2b) The state of 1300 ppm <CO concentration continues for 8 seconds or more.
(3b) The state of 800 ppm <CO concentration continues for 10 seconds or more.
(4b) The state of 600 ppm <CO concentration continues for 200 seconds or more.

  As described above, when the heating burner 41 is extinguished and then reignited, the CO sensor 12 detects the unburned gas in the combustion exhaust gas of the heating burner 41 for a while after the reignition. CO concentration increases.

  Here, FIG. 3 shows a change in the CO concentration detected by the CO sensor 12 when the heating burner 41 is extinguished and then reignited, with the vertical axis set to the CO concentration (ppm) and the horizontal axis Is set to time (seconds). In FIG. 3, α indicates a case where incomplete combustion of the heating burner 41 occurs, and β indicates a case where incomplete combustion of the heating burner 41 does not occur.

  For both α and β, the CO concentration increases from the start of the ignition process (0 seconds), and the CO concentration gradually decreases from the time when the heating burner 41 starts combustion (near 10 seconds). Then, in α where incomplete combustion occurs, the CO concentration exceeds 800 ppm in about 5 seconds and the time measurement is started, and the state in which the CO concentration exceeds 800 ppm is continued for about 10 seconds or more in about 15 seconds. When the determination condition (3b) is satisfied, incomplete combustion of the heating burner 41 is detected.

  On the other hand, in β where incomplete combustion has not occurred, since the CO concentration does not exceed 600 ppm, none of the determination conditions (1b) to (4b) is satisfied, and incomplete combustion of the heating burner 41 is detected. Not.

  Thus, by starting monitoring whether or not the determination conditions (1b) to (4b) in STEP 8 are satisfied from the time when the reignition process of the heating burner 41 is started in STEP 7, (1a) to (1d) in STEP 3 is started. It is possible to detect incomplete combustion of the heating burner 41 that cannot be detected by monitoring based on the determination condition of

  When at least one of the determination conditions (1b) to (4b) is satisfied and it can be determined that incomplete combustion of the heating burner 41 has occurred, the process branches to STEP 30, and the incomplete combustion countermeasure unit 62 extinguishes the heating burner 41 and stops the operation of the heat source device 1. At this time, the incomplete combustion countermeasure unit 62 displays an error on the display unit of the remote controller 70 indicating that incomplete combustion has occurred. By stopping the combustion of the heating burner 41 in this way, it is possible to prevent the incomplete combustion of the heating burner 41 from being continued and the decrease in the indoor oxygen concentration from proceeding.

  On the other hand, when none of the determination conditions (1b) to (4b) is satisfied, the process proceeds to STEP 9 and the incomplete combustion countermeasure unit 62 determines whether or not the heating independent operation is being performed. When the heating single operation is being performed, the process returns to STEP 8, and when the heating single operation is not being performed (when both the hot water supply operation and the heating operation are being executed, or when only the hot water supply operation is being executed), the operation returns to STEP 3. Return.

  When the operating conditions for the hot water supply operation and the heating operation are not satisfied, the combustion control unit 61 extinguishes the hot water supply burner 31 and the heating burner 41 and waits for the operation conditions to be satisfied.

  In addition, in this embodiment, although the heat source apparatus 1 provided with the hot water supply burner 31 and the heating burner 41 with the largest combustion amount smaller than the hot water supply burner 31 was shown, the object of this invention is not restricted to this structure, The 1st burner And a plurality of burners including at least a second burner having a maximum combustion amount smaller than that of the first burner, the combustion air is supplied to each burner by a single fan, and the combustion exhaust gas of each burner is single The present invention can be applied to any combustion apparatus that discharges through the collective exhaust pipe.

  Further, in this embodiment, in STEP 4 of FIG. 2, when the heating independent operation continues for 10 seconds or more, monitoring of incomplete combustion of the heating burner 41 during the heating independent operation after STEP 5 is started. When started, monitoring of incomplete combustion of the heating burner 41 may be started immediately.

  DESCRIPTION OF SYMBOLS 1 ... Heat source apparatus, 11 ... Collective exhaust pipe, 12 ... CO sensor, 30 ... Hot water supply heat exchanger, 31 ... Hot water supply burner, 40 ... Heating heat exchanger, 41 ... Heating burner, 50 ... Fan, 60 ... Controller, 61 ... Combustion control unit, 62... Incomplete combustion countermeasure unit.

Claims (2)

A plurality of burners including at least a first burner and a second burner having a maximum combustion amount smaller than that of the first burner;
A single fan for supplying combustion air to the plurality of burners;
A single exhaust passage through which the combustion exhaust gas of the plurality of burners flows;
A CO sensor provided in the exhaust passage;
A combustion control unit that controls the rotational speed of the fan so that combustion air corresponding to the amount of combustion is supplied to the burning burner when at least one of the plurality of burners is burning. When,
When at least one of the plurality of burners is burning, it is detected by the CO sensor except for a detection prohibition period from when the burning burner is ignited until a first predetermined time elapses. In a combustion apparatus provided with an incomplete combustion countermeasure unit that monitors whether or not a first determination condition for incomplete combustion based on CO concentration is satisfied, and when the first determination condition is satisfied, extinguishes a burner during combustion.
The incomplete combustion countermeasure unit monitors whether the second determination condition for incomplete combustion based on the CO concentration detected by the CO sensor is satisfied or not when only the second burner is in combustion. When the second determination condition is satisfied, the second burner is once extinguished and then re-ignited, and from the time of the re-ignition, the presence or absence of the third determination condition based on the CO concentration detected by the CO sensor is monitored, A combustion apparatus that extinguishes the second burner when the third determination condition is satisfied. The combustion apparatus according to claim 1, wherein
The incomplete combustion countermeasure unit monitors whether or not the second determination condition is satisfied when only the second burner is in combustion, and secondly after only the second burner is in a combustion state. A combustion apparatus that starts when a predetermined time has elapsed.