JP6722546B2 - Combustion device - Google Patents

Description

The present invention relates to a combustion device, and more particularly to a combustion device configured to forcibly supply combustion air of a burner into a housing by a combustion fan.

Conventionally, in a combustion device such as a water heater or a heating heat source device that recovers the heat in the combustion exhaust gas generated by the burner with a heat exchanger and heats the fluid to be heated such as water or air, the burner is stably burned. There is known a structure in which external air is forcibly introduced into the housing by a combustion fan in order to supply use air (for example, refer to Patent Documents 1 to 3).

JP, 2013-242096, A JP, 2008-2701, A JP-A-11-101449

By the way, in this type of combustion apparatus, the water in the combustion exhaust gas is condensed on the surface of the heat exchanger during the combustion operation to generate a strongly acidic drain. Therefore, after the end of combustion operation, if the air around the heat exchanger flows back to the upstream side of the air supply/exhaust path due to the effects of heat convection and negative pressure inside the housing, and the blowing of air from the exhaust stack, etc. The drain evaporated from the surface of the above, that is, the strongly acidic water vapor may cause corrosion of the components arranged upstream of the heat exchanger such as the combustion fan and the premixer.

In consideration of this problem, a method may be considered in which a check valve is provided in the air supply/exhaust path in the housing to prevent acid steam generated from the surface of the heat exchanger from flowing back to the upstream side after the combustion operation is stopped. .. However, even if the check valve is provided as described above, if an open failure occurs in which the check valve is not normally closed due to dust bite or sticking of the movable part, it is not possible to prevent the backflow of acidic water vapor, There is a problem that corrosion of the above-mentioned components progresses before the user notices.

The present invention has been made in view of the above problems, and an object thereof is to open a check valve in a combustion apparatus including a check valve that prevents air around a heat exchanger from flowing backward to the upstream side. An object of the present invention is to provide a combustion device capable of appropriately preventing a malfunction inside the device due to a failure.

The present invention provides a burner that burns a fuel gas, a heat exchanger that recovers heat in combustion exhaust gas generated by the burner and heats a fluid to be heated, and a combustion air to the burner in a supply/exhaust path in a housing. A combustion device installed in a room, equipped with a combustion fan that supplies heat and a check valve that closes the valve while the combustion fan is stopped to prevent the air around the heat exchanger from flowing back to the combustion fan. The exhaust pipe connecting portion for connecting the exhaust pipe connected to the outside, the exhaust temperature detecting means for detecting the temperature on the downstream side of the burner in the supply/exhaust path, and the exhaust detection temperature detected by the exhaust temperature detecting means are predetermined. If the exhaust detection temperature shows a predetermined variation when the combustion fan is stopped, it is determined that the check valve has an open failure and a predetermined abnormality is detected. It is characterized by performing a corresponding process.

When the check valve is normally closed when the combustion fan is stopped, the air flow in the air supply/exhaust path is naturally stopped, so that the temperature downstream of the burner in the air supply/exhaust path is unlikely to change. On the other hand, if there is an open failure in which the check valve does not close when the combustion fan is stopped, the convection and negative pressure inside the housing, and the blowing of air from the exhaust stack Due to such effects, outdoor air flows into the air supply/exhaust path through the exhaust stack. Therefore, the temperature downstream of the burner changes relatively rapidly. Therefore, as in the present invention, when the exhaust gas detection temperature shows a predetermined variation when the combustion fan is stopped, it is determined that the check valve is in the open failure state, and the predetermined abnormality handling processing is performed. Even if the check valve is not closed normally due to the cause, it is possible to suppress the use in that state by the abnormality handling processing.

The predetermined fluctuation may be a case where the exhaust gas detection temperature deviates from a predetermined range or a case where the change gradient of the exhaust gas detection temperature deviates from the predetermined range. Further, as the above-mentioned abnormality handling processing, it is conceivable to give a sound or display that the check valve is in the open failure state, prohibit the burner ignition, and the like.

Preferably, in the above combustion apparatus, an indoor temperature detecting means for detecting an ambient temperature inside a room in which the main combustion apparatus is installed is provided, and the fluctuation determining means has the exhaust detection temperature and the indoor temperature detecting means when the combustion fan is stopped. It is determined that the exhaust gas detection temperature exhibits a predetermined variation when the difference from the indoor detection temperature detected by the value deviates from the predetermined reference range.

The temperature of the outdoor air (outside air temperature) varies greatly depending on the environmental conditions such as the season, time zone, and usage area. Therefore, if the open failure of the check valve is determined based on whether or not the exhaust gas detection temperature is outside the preset temperature range after the combustion fan is stopped, it may not be possible to accurately determine due to a difference in environmental conditions. There is. However, the ambient temperature (room temperature) in the room in which the present combustion device is installed is relatively stable compared to the outside air temperature. Therefore, as in the present invention, by determining whether or not the exhaust detection temperature shows a predetermined variation based on the difference between the exhaust detection temperature and the indoor detection temperature when the combustion fan is stopped, the environmental conditions are different. However, the open failure of the check valve can be accurately determined.

Preferably, in the above combustion device, a supply cylinder connecting portion for connecting a supply cylinder connected to the outside and a supply air temperature detecting means for detecting a temperature of air supplied to the supply/exhaust path through the supply cylinder are provided, When the difference between the exhaust gas detection temperature and the supply air detection temperature detected by the supply air temperature detection means when the combustion fan is stopped becomes higher than a predetermined reference value and falls below a reference value. It is determined that the exhaust gas detection temperature has shown a predetermined fluctuation.

During combustion operation, the exhaust gas detection temperature has a value that is substantially the same as the combustion exhaust gas that has passed through the heat exchanger. On the other hand, the supply air detection temperature has a value that substantially coincides with the temperature (outside air temperature) of the outdoor air supplied to the supply/exhaust path through the supply cylinder. That is, the exhaust gas detection temperature is obviously higher than the air supply detection temperature. On the other hand, when the check valve has an open failure when the combustion fan is stopped, the outdoor air flows into the housing from both the exhaust cylinder and the supply cylinder, so the exhaust detection temperature and the supply air detection The temperatures are almost equal. Therefore, when the difference between the exhaust gas detection temperature and the supply air detection temperature when the combustion fan is stopped falls below a reference value from a state higher than the reference value as in the present invention, the exhaust detection temperature changes by a predetermined amount. It is possible to accurately determine the open failure of the check valve even in the combustion device configured to supply the combustion air of the burner from the outside through the supply cylinder by determining that the check valve is indicated.

Preferably, in the above combustion device, the fluctuation determination means indicates a predetermined fluctuation in the exhaust gas detection temperature when the temperature gradient per unit time of the exhaust gas detection temperature is larger than a predetermined reference gradient when the combustion fan is stopped. It is determined that

As in the present invention, by determining whether or not the exhaust detection temperature shows a predetermined variation based on the temperature gradient per unit time of the exhaust detection temperature when the combustion fan is stopped, even if the environmental conditions are different. The open failure of the check valve can be accurately determined.

As described above, according to the present invention, it is determined that the check valve is not normally closed due to some reason from the fluctuation of the exhaust gas detection temperature, and the predetermined abnormality handling process is performed to open the malfunction. Since it is possible to prevent the device from being continuously used in this state, it is possible to appropriately prevent a defect inside the device due to the backflow of acidic steam.

FIG. 1 is a schematic configuration diagram of a combustion device according to an embodiment of the present invention. FIG. 2 is an operation flowchart of the combustion device according to the embodiment of the present invention. FIG. 3 is a schematic diagram showing another configuration example of the combustion device according to the embodiment of the present invention.

Next, modes for carrying out the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a combustion apparatus 1 according to an embodiment of the present invention heats water (heat medium) supplied from a water supply pipe L1 into a heat exchanger 12 with combustion exhaust gas generated by a burner 11. A burner 11 for supplying hot water such as curran or shower P to the hot water use destination P through the hot water supply pipe L2, which burns the fuel gas supplied from the gas pipe L3 to generate combustion exhaust gas, and heat in the combustion exhaust gas. And a combustion fan 13 for supplying combustion air to the burner 11, and a heat exchanger 12 for recovering and heating a fluid to be heated (here, water). Installed and used.

A casing 10 that serves as an exterior case of the combustion apparatus 1 has an air supply port 101 for taking in air outside the casing 10, and combustion exhaust gas discharged from the burner 11 is discharged to the outside of the casing 10. And an exhaust port 102 for An exhaust pipe M2 communicating with the outdoor space is connected to the exhaust port 102, and the combustion exhaust gas discharged from the exhaust port 102 is exhausted to the outside through the exhaust pipe M2. That is, the exhaust port 102 serves as an exhaust pipe connecting portion for connecting the external exhaust pipe M2 to the housing 10.

Although not shown, the housing 10 is composed of a substantially rectangular box-shaped case body having an open front surface and a front panel that closes the front opening of the case body. It becomes the front. Therefore, in this specification, when the housing 10 is viewed from the front side of the front panel, the depth direction is the front-back direction of the combustion device 1, the width direction is the left-right direction of the combustion device 1, and the height direction is the up-down direction of the combustion device 1. Direction.

Inside the housing 10, a can body 20 that forms the outer shell of the heat exchanger 12 and has a substantially rectangular tubular shape with open upper and lower ends is housed. The upper end opening 31 of the can body 20 is connected to a burner body 21 that forms an outer shell of the burner 11 and has a substantially rectangular box shape with an open lower surface. On the other hand, a substantially rectangular box-shaped exhaust cover 22 having an open upper surface is connected to the lower end opening 32 of the can body 20. An exhaust outlet 221 is provided in the lower portion of the exhaust cover 22, and the exhaust outlet 102 is connected to the exhaust outlet 221 via an exhaust outlet pipe 23 extending inside the housing 10.

A gas inlet 211 is provided in the upper portion of the burner body 21, and the combustion fan 13 is connected to the gas inlet 211. Further, a premixer 14 that mixes the air taken into the housing 10 from the air supply port 101 with the fuel gas introduced from the gas pipe L3 is connected to the suction port 131 of the combustion fan 13.

In the premixer 14, one end is opened into the housing 10 and an air supply pipe 24 for guiding the air in the housing 10 to the premixer 14 and the fuel gas introduced from the gas pipe L3 are supplied to the premixer 14. It is introduced from the gas introduction pipe 25 by being connected to a gas introduction pipe 25 that guides it, and operating the combustion fan 13 and adjusting the opening degree of a mixing valve (not shown) incorporated in the premixer 14. A mixed gas of fuel gas and air in the housing 10 is supplied into the burner body 21.

A combustion plate 210 having a plurality of flame holes is provided at an opening on the lower surface of the burner body 21, and the burner 11 causes the mixed gas supplied into the burner body 21 to flow into the combustion plate 210 by the supply pressure of the combustion fan 13. The combustion exhaust gas is generated by discharging downward from the flame holes of and igniting. That is, the burner 11 is configured such that the lower surface thereof becomes the combustion surface, and the combustion amount of the burner 11 is adjusted by changing the rotation speed of the fan motor 130 that is the drive source of the combustion fan 13.

As described above, in the housing 10, from the air supply port 101 to the air supply pipe 24, the premixer 14, the housing case of the combustion fan 13, the burner body 21, the can body 20, the exhaust cover 22, and the exhaust outlet pipe 23. An air flow path, that is, an air supply/exhaust path is formed through each internal space to the exhaust port 102. By operating the combustion fan 13, the air outside the housing 10 (in this case, the room) is supplied. It is guided from the air outlet 101 to the exhaust outlet 102 through the air supply/exhaust path, and is discharged to the outside of the housing 10 (here, outside the room) through the exhaust pipe M2.

The gas introduction port 211 of the burner body 21 is opened by the pressure (supply pressure) of the air sent from the combustion fan 13 into the burner body 21 when the combustion fan 13 is operated, and is opened while the combustion fan 13 is stopped. A flap-type check valve 15 is provided which is kept closed by its own weight.

Therefore, as a result of stopping the combustion fan 13, if the check valve 15 closes normally, the mixed gas introduced into the burner body 21 by the combustion fan 13, the combustion exhaust gas supplied from the burner 12 into the can body 20, The air downstream of the combustion fan 13 such as the combustion exhaust gas discharged from the can body 20 to the exhaust gas discharge pipe 23 and the air inside the can body 20 containing the strongly acidic steam generated from the surface of the heat exchanger 12 is the combustion fan. It is prevented from flowing back to the 13 side.

The heat exchanger 12 is supplied to the inside of the can body 20 and a sensible heat exchange section 12A that recovers sensible heat in the combustion exhaust gas supplied into the can body 20 and heats the water supplied from the water supply pipe L1. And a latent heat exchange section 12B for recovering the latent heat in the combustion exhaust gas and heating the water.

The can body 20 is composed of an upper can body 20A that forms the outer shell of the sensible heat exchange section 12A and a lower can body 20B that forms the outer shell of the latent heat exchange section 12B. The burner 11 is provided above the upper can body 20A. The lower can body 20B is connected to the lower part of the upper can body 20A, and the exhaust cover 22 is connected to the lower part of the lower can body 20B. Therefore, the combustion exhaust gas generated in the burner 11 is introduced into the sensible heat exchange section 12A from above, and further led out to the exhaust cover 22 below the latent heat exchange section 12B.

The sensible heat heat exchange section 12A includes an upper can body 20A, a plurality of flat plate-shaped heat transfer fins 41 arranged side by side vertically in the upper can body 20A with a predetermined gap, and each heat transfer fin 41. And a second heat transfer pipe 43 extending substantially horizontally between the side walls of the upper can body 20A and a second heat transfer pipe 43 extending along the side wall of the upper can body 20A. ing.

The pipe ends of the first heat transfer pipe 42 and the second heat transfer pipe 43 are connected in series to each other, and form one sensible heat exchange pipe line that meanders in the upper can body 20A. The outlet end of the second heat transfer pipe 43, which is the downstream end of the sensible heat exchange conduit, is connected to the outlet pipe 26 that draws hot water to the hot water supply pipe L2, and the upstream end of the sensible heat exchange conduit. The pipe end of the first heat transfer pipe 42 on the water inlet side is connected to the latent heat exchange pipe line of the latent heat exchange section 12B via the connecting pipe 40.

The latent heat heat exchange section 12B is composed of a lower can body 20B and a heat transfer unit 44 in which a plurality of plate bodies are vertically stacked side by side to define a hollow portion through which water can pass between the plate bodies. Therefore, the hollow portion becomes one latent heat exchange pipe line.

On one side surface of the heat transfer unit 44, a water inlet side pipe connecting portion 33 which is an upstream end of the latent heat exchange pipeline and a water outlet side pipe connecting portion 34 which is a downstream end of the latent heat exchange pipeline are provided. The connection pipe 40 is connected to the water outlet side pipe connecting portion 34, and the water inlet pipe 27 for introducing water from the water supply pipe L1 is connected to the water inlet side pipe connecting portion 33.

Therefore, during the hot water supply operation, the water introduced from the water supply pipe L1 to the water inlet pipe 27 passes through the heat transfer unit 44 of the latent heat exchange unit 12B to be guided to the connecting pipe 40, and further to the sensible heat exchange unit 12A. It passes through the 1st heat transfer pipe 42 and the 2nd heat transfer pipe 43, and is drawn out from the hot water supply pipe 26 to the hot water supply pipe L2. At that time, the sensible heat in the combustion exhaust gas supplied into the housing 10 is recovered by the heat transfer fins 41, the first heat transfer tubes 42, and the second heat transfer tubes 43, and the latent heat in the combustion exhaust gas is transferred to the heat transfer unit. Recovered by 44. As a result, hot water having a desired temperature is supplied to the hot water utilization destination P.

At the bottom of the exhaust cover 22, the surfaces of the heat transfer unit 44, the heat transfer fins 41, the first heat transfer tubes 42, and the second heat transfer tubes 43 when the sensible heat and latent heat in the combustion exhaust gas are recovered by the heat exchanger 12. A drain neutralizer 16 that collects and neutralizes the strongly acidic drain that has been condensed and generated in the bottom of the exhaust cover 22 is connected to the exhaust cover 22. The drain collected in the drain neutralizer 16 is neutralized by the neutralizing agent loaded inside and then discharged to the outside of the apparatus.

A water amount sensor 51 that detects the amount of water supplied to the heat exchanger 12 is disposed in the water inlet pipe 27. Further, an exhaust temperature sensor 52 is provided at a position near the connecting portion of the exhaust outlet pipe 23 with the exhaust port 102 as an exhaust temperature detecting means for detecting a temperature on a downstream side of an arrangement portion of the burner 11 in the supply/exhaust path. In the vicinity of the air supply port 101 inside the housing 10, an indoor temperature sensor 53 is provided as an indoor temperature detecting means for detecting an ambient temperature outside the housing 10.

A control circuit 6 for controlling the hot water supply operation of the combustion device 1 such as ignition and extinguishing of the burner 11, adjustment of the rotation speed of the fan motor 130, adjustment of the opening degree of the mixing valve of the premixer 14 is provided in the housing 10. The ignition device (not shown) of the burner 11, the fan motor 130, the mixing valve of the premixer 14, the water amount sensor 51, the exhaust temperature sensor 52, and the room temperature sensor 53, which are incorporated, are connected to the control circuit 6 through electrical wiring. ing. In addition, the control circuit 6 is connected to an operation terminal (not shown) for displaying the operating state of the combustion device 1, outputting audio, and setting operating conditions.

Although not shown, the control circuit 6 includes a combustion control unit that ignites and extinguishes the burner 11, adjusts the amount of combustion, a supply/exhaust control unit that operates and stops the combustion fan 13, adjusts the number of revolutions, and a water amount sensor 51. A water discharge determination unit that determines whether or not water is being discharged to the hot water use destination P based on the amount of water, and when the water discharge to the hot water use destination P is started, the combustion fan 13 is operated and the mixed gas is supplied to the burner 11. Is supplied and the burner 11 is ignited, while when the water supply to the hot water utilization destination P is stopped, the supply of the fuel gas to the burner 11 is interrupted to extinguish the burner 11, and the combustion operation execution unit, etc. It has a circuit configuration.

In addition, the control circuit 6 determines, after the completion of the combustion operation, the absolute value of the difference between the temperature T2 detected by the exhaust temperature sensor 52 (exhaust temperature detected) and the temperature detected by the indoor temperature sensor 53 (room detected temperature) T3 as a predetermined reference. An open failure determination unit that determines a valve closing failure of the check valve 15 based on whether or not the value Ts has been reached. If the check valve 15 is determined to be a valve close failure, a message to that effect is displayed or displayed on the operating terminal. It has a circuit configuration such as a notification control unit for making a sound notification, a storage unit for storing the reference value Ts, and a timer unit for measuring the elapsed time during combustion operation.

As shown in FIG. 2, in the combustion apparatus 1 according to the present embodiment, first, when the operation switch (not shown) of the operation terminal is turned on, it is determined whether the water amount detected by the water amount sensor 51 is equal to or more than a predetermined value. Then, the monitoring is started (ST1). That is, the operation standby state is set.

When the hot water utilization destination P starts water discharge and the amount of water detected by the water amount sensor 51 exceeds a predetermined value, the combustion fan 13 is operated at a predetermined rotation speed, and the mixing valve of the premixer 14 is opened to open the burner. The supply of fuel gas to 11 is started and the burner 11 is ignited. That is, the combustion operation is started (ST2). As a result, high-temperature combustion exhaust gas is supplied from the burner 11 into the can body 20 of the heat exchanger 12, and the water flowing in the heat exchanger 12 is heated. As a result, the hot water at the desired temperature is supplied to the hot water use destination P.

When water output is stopped at the hot water use destination P and the amount of water detected by the water amount sensor 51 becomes less than a predetermined value, the mixing valve of the premixer 14 is closed and the supply of fuel gas to the burner 11 is stopped to turn off the burner 11. Extinguish the fire and stop the combustion fan 13. That is, the combustion operation is stopped (ST3 to ST4). As a result, the supply of combustion exhaust gas into the can body 20 is stopped.

When the combustion fan 13 is stopped along with the end of the combustion operation, and the supply pressure of the combustion fan 13 is lowered, and the check valve 15 is normally closed, the outdoor air is transferred to the casing 10 through the exhaust pipe M2. Since it is prevented from flowing into the supply/exhaust path, the detected temperature T2 of the exhaust temperature sensor 52 becomes a value (for example, 50 to 60° C.) that is substantially equal to the temperature of the combustion exhaust gas after passing through the heat exchanger 12. Become. On the other hand, the detected temperature T3 of the indoor temperature sensor 53 is a value that substantially matches the temperature of the indoor air supplied into the housing 10 during the combustion operation, that is, room temperature (for example, 25° C. in summer and 20° C. in winter). become. Therefore, even if a predetermined time (for example, 30 seconds) elapses after the combustion fan 13 is stopped, the absolute value |T2-T3| of the difference between the detected temperatures T2 and T3 is the reference value Ts (for example, 20° C.). ) Maintained at higher values. Therefore, it is determined that the check valve 15 is normally closed, and the process returns to step ST1 (ST5, ST1).

On the other hand, the combustion fan 13 is stopped along with the end of the combustion operation, and the check valve 15 is normally closed due to dust clogging, sticking of moving parts, etc., even though the supply air pressure of the combustion fan 13 has dropped. If there is no valve closing failure (open failure), outdoor air having a temperature lower than the temperature of the combustion exhaust gas after passing through the heat exchanger 12 flows into the exhaust outlet pipe 23 through the exhaust pipe M2. Therefore, in this case, the detected temperature T2 of the exhaust temperature sensor 52 drops to the temperature of the outdoor air flowing into the exhaust outlet pipe 23, that is, a value close to the outdoor temperature (for example, 33° C. in summer and 5° C. in winter). However, the absolute value |T2-T3| of the difference between the detected temperatures T2 and T3 becomes smaller. As a result, if the absolute value |T2-T3| of the difference between the two detected temperatures T2 and T3 becomes equal to or less than the reference value Ts, it is determined that the check valve 15 is not normally closed and is in a valve closing failure state. Then, the fact is displayed or voiced from the operation terminal (ST6).

The notification of the valve closing failure of the check valve 15 is continued until a predetermined reset operation is performed by a setting switch (not shown) of the operation terminal (or only the voice output is stopped after a certain period of time elapses), and then reset. If the operation is performed, the notification is stopped and the process returns to the step ST1 (ST7 to ST8, ST1).

As described above, according to the combustion apparatus 1 according to the above-described embodiment, after the combustion operation is completed and the combustion fan 13 is stopped, the exhaust temperature sensor 52 which is obviously higher than the detection temperature T3 of the indoor temperature sensor 53 is detected. When the detected temperature T2 drops and the difference between the detected temperatures T2 and T3 becomes small, that is, when the difference between the detected temperatures T2 and T3 deviates from the reference range, the detected temperature T2 of the exhaust temperature sensor 52 is abnormal. However, since it is notified that the check valve 15 is in the valve closing failure state, it is possible to prevent the check valve 15 from being continuously used in that state. Accordingly, it is possible to appropriately prevent the problem that the acidic steam generated from the surface of the heat exchanger 12 flows backward to the upstream side and corrodes the components such as the combustion fan 13 and the premixer 14.

In addition, when it is determined that the check valve 15 has a valve closing failure, the failure of the valve closing is notified, or instead of the notification of the valve closing failure, the operation of the combustion fan 13 and the opening of the premixer 14 are performed. It may be provided with a combustion limiting function that prohibits the valve and does not ignite the burner 11. With this, it is possible to reliably prevent the check valve 15 from being continuously used in a valve closing failure state, and therefore it is possible to more appropriately prevent a defect inside the device due to a backflow of acidic water vapor.

In the above-described embodiment, the exhaust detection temperature T2 and the indoor detection temperature are determined by the elapse of a predetermined time period as a process of determining whether or not the exhaust detection temperature T2 shows an abnormal change after the combustion fan 13 is stopped. Although the one configured to determine whether the absolute value of the difference from T3 has become smaller than the reference value Ts has been described, the exhaust gas detection temperature T2 at the time when a predetermined time has elapsed after the combustion fan 13 was stopped. May be determined to be lower than the reference value Ts, and if it is lower than the reference value Ts, it may be determined to be a valve closing failure. Also, based on the exhaust gas detection temperature T2 before the combustion operation is started (for example, at the time of the operation standby state), the environmental conditions such as the season, the time zone, and the usage area are determined, and the determination result of the environmental conditions is used. Based on this, it is selected whether the indoor detected temperature T3 is subtracted from the exhaust detected temperature T2 or the exhaust detected temperature T2 is subtracted from the indoor detected temperature T3, and it is determined whether or not the calculated value is smaller than the reference value Ts. It may be configured as follows.

Further, in the above-described embodiment, the reference value Ts set in advance is used to determine the abnormal fluctuation of the exhaust gas detection temperature T2. However, when the detected water amount of the water amount sensor 51 becomes equal to or more than the predetermined value, That is, the absolute value of the difference between the exhaust detection temperature T2 and the indoor detection temperature T3 at the time when the combustion operation is started may be set to the reference value Ts to determine the abnormal fluctuation of the exhaust detection temperature T2.

Even before the combustion operation is started, the exhaust gas detection temperature T2 is affected by the heat radiation from the exhaust air outlet pipe 23 and the vicinity of the exhaust port 102 heated by the outside air or the previous combustion operation, and the indoor detection temperature T3. Can be higher than. However, by setting the reference value Ts from the difference between the exhaust gas detection temperature T2 and the indoor detection temperature T3 at the time when the combustion operation is started as described above, abnormal fluctuations in the exhaust gas detection temperature T2 can be prevented even if the environmental conditions are different. Can be accurately determined.

Further, in the above-described embodiment, the case where the ambient temperature outside the housing 10 is detected by the indoor temperature sensor 53 provided near the air supply port 101 in the housing 10 has been described. If the ambient temperature of the outside can be properly detected, the indoor temperature sensor 53 may be provided outside the constituent wall of the housing 10, or the air supply pipe 24 may be provided with the indoor temperature sensor 53. The indoor temperature sensor 53 may be provided at the suction port 131 of the combustion fan 13.

Further, in the above-described embodiment, the valve closing failure of the check valve 15 is determined based on the difference between the exhaust gas detection temperature T2 and the indoor detection temperature T3 when the combustion operation is completed and the combustion fan 13 is stopped. However, it has a function of executing the post-purge operation in which the combustion fan 13 is operated for a predetermined time after the combustion operation of the burner 11 is stopped to discharge the combustion exhaust gas remaining in the supply/exhaust path to the outside of the housing 10. Then, it is configured to determine the valve closing failure of the check valve 15 based on the difference between the exhaust detection temperature T2 and the indoor detection temperature T3 when the post-purge operation is finished and the combustion fan 13 is stopped. May be

More specifically, when the post-purge operation is terminated, the combustion fan 13 is stopped and the supply pressure of the combustion fan 13 is lowered, and when the check valve 15 is normally closed, the outdoor air is exhausted from the exhaust pipe M2. It is prevented from flowing into the air supply/exhaust path of the housing 10 through the. Therefore, in this case, both the detected temperature T2 of the exhaust temperature sensor 52 and the detected temperature T3 of the indoor temperature sensor 53 are substantially the same as the temperature (room temperature) of the indoor air supplied to the air supply/exhaust path of the housing 10 by the post-purge operation. The absolute values |T2-T3| of the difference between the two detected temperatures T2 and T3 change within a range equal to or less than the reference value Ts even if the values become coincident with each other and a predetermined time elapses after the combustion fan 13 is stopped. .. Therefore, it is determined that the check valve 15 is normally closed.

On the other hand, when the combustion fan 13 is stopped along with the end of the post-purge operation and the supply pressure of the combustion fan 13 is lowered, but the check valve 15 is not normally closed, the temperature is higher than the room temperature. Alternatively, outdoor air lower than room temperature flows into the air supply/exhaust path of the housing 10 through the exhaust pipe M2. Therefore, in this case, the temperature T2 detected by the exhaust gas temperature sensor 52 becomes a value substantially equal to the temperature of the outdoor air (outside air temperature) until the predetermined time elapses after the combustion fan 13 is stopped, and Since the detected temperature T3 of the indoor temperature sensor 53 is a value substantially equal to the room temperature, the absolute value |T2-T3| of these differences is larger than the reference value Ts. Therefore, it is determined that the check valve 15 is in the valve closing failure state.

As described above, even in the combustion apparatus 1 having the post-purge function, the detected temperature T2 of the exhaust temperature sensor 52 and the detected temperature T3 of the indoor temperature sensor 53, which are substantially the same after the combustion fan 13 is stopped, are detected. If a difference of a predetermined value or more occurs between the two, that is, if the difference between the detected temperatures T2 and T3 deviates from the reference range, it is considered that the detected temperature T2 of the exhaust temperature sensor 52 indicates an abnormal variation and the valve closing failure occurs. Therefore, the same operational effect as the above-described embodiment is obtained.

Further, in the combustion apparatus 1 according to the above-described embodiment, the check valve 15 is determined based on whether the difference between the exhaust detection temperature T2 and the indoor detection temperature T3 when the combustion fan 13 is stopped is smaller than the reference value Ts. However, the check valve 15 is determined based on whether the temperature gradient ΔT2 of the exhaust gas detection temperature T2 per unit time when the combustion fan 13 is stopped is larger than the reference gradient ΔTs. It may be configured to determine the valve closing failure.

More specifically, when the combustion fan 13 is stopped with the end of the combustion operation, and the supply pressure of the combustion fan 13 is lowered, and the check valve 15 is normally closed, the outdoor air passes through the exhaust pipe M2. It is prevented from flowing into the air supply/exhaust path of the housing 10. Therefore, in this case, the detected temperature T2 of the exhaust gas temperature sensor 52 falls relatively gently due to natural heat dissipation.

On the other hand, when the combustion fan 13 is stopped with the end of the combustion operation and the supply pressure of the combustion fan 13 is lowered, but the check valve 15 is not normally closed, the heat exchanger 12 The outdoor air having a temperature lower than that of the combustion exhaust gas after passing through the exhaust gas flows into the exhaust outlet pipe 23 through the exhaust pipe M2. Therefore, in this case, the temperature T2 detected by the exhaust temperature sensor 52 rapidly drops to a value close to the outside air temperature.

Therefore, in the present embodiment, after the combustion operation ends and the combustion fan 13 is stopped, the temperature gradient ΔT2 per unit time (for example, 10 seconds) of the exhaust gas detection temperature T2 is the reference gradient ΔTs (for example, 5 deg). When the following is true, that is, when a rapid temperature drop is not recognized, it is determined that the check valve 15 is normally closed. On the other hand, when the temperature gradient ΔT2 is larger than the reference gradient ΔTs, it is determined that the check valve 15 is in the valve closing failure state, and the operation terminal informs the operator through a display or voice that the valve closing failure occurs. The abnormality handling processing such as is performed. As a result, the same operational effects as those of the above-described embodiment can be obtained.

According to the present invention, as shown in FIG. 3, an external supply cylinder M1 connected to the outside is connected to the exhaust port 102, and the combustion air of the burner 11 is guided from the outside into the housing 10 through the supply cylinder M1. It is also applicable to the combustion device 1A configured as described above.

More specifically, the combustion apparatus 1A has a supply air temperature detecting means for detecting the temperature of the air supplied to the supply/exhaust passage in the housing 10 through the supply cylinder M1 at a position near the supply opening 101 in the housing 10. A supply air temperature sensor 54 is provided.

In addition, the combustion device 1A detects the temperature of the exhaust gas temperature sensor 52 (exhaust gas detection temperature) until a predetermined time (for example, 30 seconds) elapses after the combustion operation ends and the combustion fan 13 is stopped. It is configured to determine the valve closing failure of the check valve 15 depending on whether or not the difference between T2 and the temperature detected by the air supply temperature sensor 54 (air supply detection temperature) T4 is equal to or less than a predetermined reference value Ts. ..

In this configuration, when the check fan 15 is normally closed as a result of the combustion fan 13 being stopped as the combustion operation ends, the outdoor air flows into the supply/exhaust path of the housing 10 through the exhaust pipe M2. Therefore, the exhaust gas detection temperature T2 becomes a value that substantially coincides with the temperature of the combustion exhaust gas after passing through the heat exchanger 12. On the other hand, the supply air detection temperature T4 becomes a value that substantially matches the temperature (outside air temperature) of the outdoor air supplied into the housing 10 during the combustion operation. Therefore, the difference between the detected temperatures T2 and T4 is relatively large.

On the other hand, if the check valve 15 is not normally closed even though the combustion fan 13 is stopped with the end of the combustion operation, the temperature of the combustion exhaust gas after passing through the heat exchanger 12 The outdoor air lower than that flows into the exhaust gas outlet pipe 23 through the exhaust pipe M2. Therefore, in this case, the detected temperature T2 of the exhaust temperature sensor 52 drops to a value close to the temperature (outside air temperature) of the outdoor air flowing into the exhaust outlet pipe 23, and the difference T2-T4 between the two detected temperatures T2 and T4 is calculated. Get smaller.

As described above, even in the combustion apparatus 1A configured to guide the combustion air of the burner 11 from the outside to the inside of the housing 10 through the supply cylinder M1, the exhaust gas detection temperature T2 when the combustion fan 13 is stopped and When the difference from the supply air detection temperature T4 is higher than the reference value Ts and becomes equal to or lower than the reference value Ts, the check valve 15 is determined to be in the valve closing failure state. The same operational effect as the form is achieved.

INDUSTRIAL APPLICABILITY The present invention is not limited to a water heater having only a hot water supply function, and can be applied to a water heater having a bath heating function, a heating heat source device that circulates hot water to a hot water heating terminal, a heat source device of a hot water supply type hot water supply system, A heat source unit that has only a sensible heat exchanger, the combustion exhaust gas generated by a burner is supplied to the inside of the heat exchanger to recover heat, and the indoor and outdoor air introduced around the installation part of the heat exchanger ( It can also be applied to a heating device that heats a heating fluid).

Further, the present invention is not limited to the so-called downward combustion type combustion device configured to flow the combustion exhaust gas from the upper side to the lower side of the heat exchanger as in the above-described embodiment, and is not limited to the heat exchanger. It can also be applied to a so-called upward combustion type combustion device configured to flow the combustion exhaust gas from below to above.

1 Combustion Device 10 Housing 101 Air Supply Port 102 Exhaust Port (Exhaust Cylinder Connection)
11 Burner 12 Heat Exchanger 13 Combustion Fan 15 Backflow Prevention Valve 52 Exhaust Temperature Sensor (Exhaust Temperature Detector)
53 Indoor temperature sensor (indoor temperature detection means)
M3 Exhaust stack T2 Exhaust detection temperature T3 Indoor detection temperature

Claims (4)

A burner that burns the fuel gas, a heat exchanger that heats the fluid to be heated by recovering the heat in the combustion exhaust gas generated by the burner, and a combustion air that supplies the combustion air to the burner in the air supply/exhaust path in the housing. A combustion device installed in a room, comprising a fan and a backflow prevention valve that is closed when the combustion fan is stopped to prevent air around the heat exchanger from flowing back to the combustion fan side.
An exhaust stack connection portion for connecting an exhaust stack connected to the outside,
Exhaust temperature detecting means for detecting the temperature on the downstream side of the burner in the supply/exhaust path,
And a variation determination means for determining whether or not the exhaust temperature detected by the exhaust temperature detection means exhibits a predetermined variation,
A combustion apparatus, wherein when the exhaust gas detection temperature shows a predetermined fluctuation when the combustion fan is stopped, it is determined that the check valve has an open failure and a predetermined abnormality handling process is performed. The combustion device according to claim 1,
An indoor temperature detecting means for detecting an ambient temperature in the room where the combustion device is installed is provided,
The variation determination means causes a predetermined variation in the exhaust gas detection temperature when the difference between the exhaust gas detection temperature and the indoor temperature detected by the indoor temperature detection means deviates from a predetermined reference range when the combustion fan is stopped. A combustion device, characterized in that it is judged as shown. The combustion device according to claim 1,
A supply cylinder connecting portion for connecting a supply cylinder connected to the outside,
And a supply air temperature detecting means for detecting the temperature of the air supplied to the supply/exhaust path through the supply cylinder,
When the difference between the exhaust gas detection temperature and the supply air detection temperature detected by the supply air temperature detection means when the combustion fan is stopped becomes higher than a predetermined reference value and falls below a reference value. In addition, the combustion device is characterized in that it is determined that the exhaust gas detection temperature exhibits a predetermined fluctuation. The combustion device according to claim 1,
The variation determining means determines that the exhaust detection temperature exhibits a predetermined variation when the temperature gradient of the exhaust detection temperature per unit time is larger than a predetermined reference gradient when the combustion fan is stopped. , Combustion equipment.

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