JP2014081169A - Forced supply and exhaust type warm air heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forced supply and exhaust type warm air heater including exhaust leakage detection means capable of detecting also leakage of fine combustion exhaust and having high safety.SOLUTION: In the forced supply and exhaust type warm air heater configured so that air supply and exhaust pipes (11), (12) opened to the outside through a wall (3) are connected to an apparatus body (1) provided with a suction port (13) for sucking indoor air and a blowout port (20) for blowing out warm air, and a gas burner (2), a heat exchanger (15), a combustion fan (21) for sucking outdoor air from the air supply pipe (12) and supplying the sucked air to the gas burner, and a convection fan (22) for heat-exchanging indoor air taken from the suction port (13) into the apparatus body (1) by the heat exchanger (15) and then blowing out the heat-exchanged air from the blowout port (20) into a room as warm air are included in the apparatus body (1) to exhaust combustion exhaust to the outside through the exhaust pipe (11), an NOx sensor (5) is arranged in the vicinity of the suction port (13) as exhaust detection means for detecting leakage of combustion exhaust into the room.

Description

  The present invention relates to a forced air supply / exhaust hot air heater, and more particularly to a forced air supply / exhaust hot air heater equipped with exhaust leakage detection means for detecting leakage of combustion exhaust from the hot air heater.

As shown in FIG. 4, a forced air supply / exhaust hot air heater called an FF type is usually provided with an air supply / exhaust pipe (41) (42) on a wall (3) on an appliance main body (30) installed indoors. The air supply / exhaust ports (31), (32) of the air supply / exhaust pipes (41), (42) are open to the outdoors. A gas burner (302) and a combustion fan (321) for sending combustion air to the gas burner (302) are disposed below the combustion cylinder (34) provided in the instrument main body (30).
By the operation of the combustion fan (321), outdoor air is taken in from the air supply port (31), passes through the air supply pipe (41), and is supplied to the gas burner (302) as combustion air.

  Combustion exhaust generated by the combustion of the gas burner (302) rises in the combustion cylinder (34), and the indoor air taken into the instrument body (30) from the intake port (33) by the heat exchanger (35). After the heat exchange is performed, the combustion exhaust whose temperature has dropped is exhausted to the outside through the exhaust pipe (42) from the exhaust port (32). The room air whose temperature has been raised by the heat exchange is blown into the room as warm air from the blower outlet (320) provided on the front surface of the instrument body (30). The blowout of warm air from the air outlet (320) and the intake of room air from the air inlet (33) into the instrument body (30) are repeatedly performed by the convection fan (322), and the room air is It is warmed as it circulates through 30).

  In the conventional forced air supply / exhaust hot air heater as described above, the interior of the combustion exhaust at the time of abnormal combustion is placed in a predetermined position in the appliance main body (30) or in the vicinity of the connection portion of the exhaust pipe (42). A CO sensor (4) is provided as exhaust leak detection means for detecting leaks into the exhaust. When the CO sensor (4) reacts, it is determined that combustion exhaust gas containing unburned gas is leaking from the heat exchanger (35), the exhaust pipe (42), etc., and the combustion fan (321) and convection fan ( 322) is stopped and the solenoid valve or the like provided in the gas passage is closed, and the combustion of the gas burner (302) is stopped (Patent Document 1).

JP 2007-162985 A

  However, the CO sensor (4) as described above has an abnormal combustion in which a normal combustion cannot be performed due to a large disconnection of the exhaust pipe (42) or a large hole in the heat exchanger (35). It reacts when high concentrations of carbon monoxide are generated, and it cannot detect minute leaks of combustion exhaust that do not generate high concentrations of carbon monoxide, such as leaks from exhaust pipes during normal combustion. .

  In the case of an open type heater that exhausts combustion exhaust into the room, regular ventilation during use is promoted, but in the FF type hot air heater as described above, the combustion exhaust is Since the exhaust pipe (42) is discharged to the outside through the exhaust port (32), regular ventilation is not required. Therefore, even if the combustion exhaust gas leaks from the exhaust pipe (42) or the heat exchanger (35), it will not be noticed as long as it is small, and it will continue to be used as it is and will contaminate the indoor air. .

  The present invention has been made in view of the above problems, and an object of the present invention is high safety provided with an exhaust leak detection means capable of detecting a slight leak of combustion exhaust before reaching abnormal combustion. It is to provide a forced air supply / exhaust hot air heater.

The present invention taken to achieve the above object
A supply / exhaust pipe that penetrates the wall and opens to the outside is connected to an appliance body provided with an intake port for taking in indoor air and an outlet through which hot air is blown out.
In the instrument body,
A gas burner, a heat exchanger that exchanges heat between combustion exhaust generated by the combustion of the gas burner and the room air, a combustion fan that sucks outdoor air through the air supply pipe and supplies the air to the gas burner, and A convection fan that blows indoor air taken into the appliance body into the room from the outlet as warm air after heat exchange with the heat exchanger;
In the hot air heater of forced air supply and exhaust type, the combustion exhaust after heat exchange is exhausted to the outside through the exhaust pipe,
A forced air supply / exhaust type hot air heater in which a NOx sensor is provided in the vicinity of the intake port as exhaust leakage detection means for detecting leakage of combustion exhaust from a heat exchanger, an exhaust pipe or the like.

The above means operates as follows.
By the operation of the combustion fan, outdoor air is supplied to the gas burner in the instrument body through the air supply pipe, and combustion exhaust is generated when the gas burner burns. Combustion exhaust contains harmful substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) .In normal combustion, this combustion exhaust is exhausted by the heat exchanger. After the heat exchange with room air taken into the appliance main body, the whole is discharged to the outside through the exhaust pipe.
When combustion exhaust leaks into the instrument main body due to deterioration or damage of the heat exchanger, the combustion exhaust is blown out into the room together with warm air from the outlet of the instrument main body by a convection fan. Is taken into the instrument body from the air inlet together with the room air.

Since the NOx sensor is provided at a predetermined position in the vicinity of the intake port, the combustion exhaust leaking from the heat exchanger and discharged into the room or the combustion exhaust leaking into the room from the exhaust pipe outside the instrument body is detected. When nitrogen oxide is detected in the combustion exhaust gas by the NOx sensor when it is taken into the instrument main body from the intake port, the leakage of the combustion exhaust gas into the room can be detected with certainty.
In the conventional CO sensor, a large amount of combustion exhaust leaked and the gas burner abnormally burned, and it could only be detected for the first time when a high concentration of 200 to 300 ppm of CO was generated. The NOx concentration is higher than the CO concentration. Furthermore, the NOx sensor is more responsive than the CO sensor and can detect even low concentrations of nitrogen oxides with high accuracy. It reacts and can detect NOx. Thereby, it can be recognized that the combustion exhaust gas is leaking into the room before the abnormal combustion is reached.

  In the forced air supply / exhaust type hot air heater, preferably, the combustion of the gas burner is stopped when the NOx sensor detects a NOx concentration equal to or higher than a reference value during the combustion operation of the gas burner, and the NOx sensor is stopped while the combustion is stopped. A control unit that measures the NOx concentration again and restarts the combustion of the gas burner when the NOx concentration during combustion stop does not decrease compared to the concentration during combustion.

Since the NOx sensor can detect even low concentrations of NOx, when another combustion device is used simultaneously with the heater in the same room, it reacts with NOx in the combustion exhaust discharged from the other combustion device. There is a risk of false detection.
For this reason, in the forced air supply / exhaust type hot air heater, when the NOx concentration detected by the NOx sensor becomes equal to or higher than the reference value, the combustion of the gas burner is once stopped. As a result, the combustion exhaust is not discharged from the heater. Therefore, when it is caused by the combustion exhaust discharged from the heater, the NOx concentration is lowered, resulting from the combustion exhaust discharged from another combustion device. The NOx concentration does not change.
Therefore, by comparing the NOx concentration before stopping the combustion of the heater and the NOx concentration during stopping the combustion, it can be determined whether the NOx concentration higher than the reference value is caused by the combustion exhaust of the heater. It is possible to reliably determine whether or not to continue the operation of the gas burner.

  As described above, according to the present invention, the conventional CO sensor could not detect the leakage of combustion exhaust gas only when high concentration of carbon monoxide was generated due to abnormal combustion. By mounting a NOx sensor that can be detected well, the NOx sensor can quickly and reliably detect even a slight leak in the combustion exhaust before abnormal combustion occurs, so you can quickly notice defects in the instrument body. be able to. Therefore, a highly safe forced air supply / exhaust hot air heater can be provided.

It is the schematic which shows the internal structure by the side of the forced air supply / exhaust type hot air heater in embodiment of this invention. It is the schematic which shows the internal structure of the front side of the forced air exhaust type hot air heater in embodiment of this invention. It is a flowchart for demonstrating control operation | movement of the forced air supply / exhaust type hot air heater in embodiment of this invention. It is explanatory drawing of the conventional forced air supply / exhaust type hot air heater.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of the internal structure when the hot air heater according to the present embodiment is viewed from the side, and FIG. 2 is a schematic diagram of the internal structure when the hot air heater is viewed from the front. .
As shown in FIG. 1, the hot air heater of this embodiment is an FF type gas hot air heater, and the appliance main body (1) arranged indoors is located close to the wall (3) of the house. An air inlet (13) for taking in indoor air is formed in the upper back of the appliance body (1), and warm air heated in the appliance body (1) is blown out indoors at the lower front. An air outlet (20) is formed.

The appliance body (1) is provided with a blower cylinder (100) that constitutes a blower passage (10) .In the blower pipe (100), an intake port (13), a blower passage (10), and further A pair of convection fans (22) that circulate room air through the blower outlet (20) and a combustion cylinder (14) that heats the air flowing through the blower passage (10) are provided.
As shown in FIG. 2, the intake port (13) is formed in two on the left and right sides, and a filter (23) for preventing intrusion of dust is attached to each of the intake ports (13).
The pair of convection fans (22) are sirocco fans, and are driven to rotate by a fan motor (22a) provided in the center, and the air taken into the instrument body (1) from the air inlet (13) After being sucked from the side of (22) (left and right direction in FIG. 2), it is sent out toward the blower passage (10) in the blower cylinder (100).

  In the combustion cylinder (14), a gas burner (2) and a heat exchanger (15) including a main heat exchanger (15a) and a sub heat exchanger (15b) are provided above the gas burner (2). An air supply pipe (12) for supplying combustion air to the gas burner (2) is connected to the combustion cylinder (14), and an exhaust pipe (11) for discharging the combustion exhaust in the combustion cylinder (14). The heat exchanger (15) is connected via the auxiliary heat exchanger (15b). The air supply pipe (12) and the exhaust pipe (11) extend outside the instrument main body (1), and have a coaxial double structure and are led out outdoors. The supply pipe (12) is provided with a combustion fan (21) for forcibly supplying combustion air to the gas burner (2) in the combustion cylinder (14). The combustion fan (21) is a sirocco fan set so as to be rotationally driven by a fan motor (21a).

The upstream end of the gas burner (2) is connected to the gas supply pipe (24), and the fuel gas supplied from the gas supply pipe (24) is introduced from the supply pipe (12) into the gas burner (2) in the combustion cylinder (14). The combustion air is mixed and the mixture is burned.
The combustion cylinder (14) has an ignition electrode (16) for igniting the gas burner (2), and a flame rod (17) for detecting whether the gas burner (2) is not ignited or misfiring. It is arranged.

  As shown in FIG. 2, an original solenoid valve (51), a temperature control solenoid valve (52), and a proportional valve (53) are interposed in the gas supply pipe (24). The original solenoid valve (51) and the temperature control solenoid valve (52) are opened by energization, and in the opened state, the fuel gas is sent from the gas supply pipe (24) to the gas burner (2), and the energization is stopped. In the state, the fuel gas supply pipe (24) is shut off. The proportional valve (53) adjusts the amount of fuel gas supplied to the gas burner (2) by increasing the opening of the valve in proportion to the amount of energization current.

  Further, as shown in FIG. 2, the appliance body (1) is provided with a room temperature thermistor (27) for detecting the temperature in the room, and the blower cylinder (100) constituting the blower passage (10) is provided with 2 Two thermal fuses (28) are installed.

  On the upper surface of the appliance body (1), a display operation unit (25) provided with various operation switches such as ignition and fire extinguishing is provided, and the operation of each unit according to the operation of the display operation unit (25) is It is controlled by the control unit (26).

When the operation switch is turned on at the display operation unit (25), the fan motor (21a) is driven by the command from the control unit (26) to rotate the combustion fan (21), and the original solenoid valve (51), The temperature control solenoid valve (52) and the proportional valve (53) are opened, and the ignition electrode (16) is energized. Thus, when the gas burner (2) is ignited and flame is detected by the frame rod (17), the combustion operation is started.
In addition, the convection fan (22) that is rotated by the drive of the fan motor (22a) sends the indoor air into the air passage (10) in the instrument body (1) through the air inlet (13), and the combustion cylinder Heat is exchanged by the heat exchanger (15) in (14), and is heated and blown into the room from the outlet (20). The warm air blown into the room from the air outlet (20) is again taken into the appliance body (1) from the air inlet (13) and reheated, and then blown out from the air outlet (20). Thus, the indoor air is circulated and heated through the inside of the appliance body (1), and the operation of each part continues until the temperature detected by the room temperature thermistor (27) reaches the set temperature.

  The combustion exhaust gas whose temperature has dropped in the heat exchanger (15) passes through the exhaust pipe (11) and is exhausted outdoors from the exhaust port (11a).

As described above, the combustion exhaust generated in the appliance main body (1) is discharged to the outside through the exhaust pipe (11), so it will not leak into the room unless there is a problem with the appliance, but the heat exchanger ( 15) If the exhaust pipe (11) is damaged or abnormal, it may leak into the room. In order to detect this, a NOx sensor (5) for detecting nitrogen oxides is provided as an exhaust leak detection means at a predetermined position of the blower cylinder (100) located in the vicinity of the intake port (13).
When combustion exhaust gas is leaked into the room air, when the air once blown into the room through the air outlet (20) is taken into the appliance body (1) from the air inlet (13), the NOx sensor (5 ) Detects nitrogen oxides, so that it can be recognized that combustion exhaust gas is leaking into the room.

As the NOx sensor, a sensor that can detect even a NOx concentration of several ppm, such as a vehicle-mounted sensor or a garage / parking sensor, can be used.
Since this type of NOx sensor responds quickly to low concentrations of NOx, for example, it may respond to NOx discharged from combustion devices other than the instrument body (1).
For this reason, the control unit (26) in the hot air heater of the present embodiment indicates that the NOx sensor (5) mounted on the appliance body (1) has reacted to the NOx discharged from the appliance body (1). After confirming, it has a control configuration for continuing or stopping the combustion of the gas burner (2).
FIG. 3 is a flowchart showing an example of the control operation.

When the user turns on the operation switch of the display / operating unit (25), in step S1, it is confirmed whether there is a problem with the load / circuit in each place. If any abnormality is found in the circuit, the control is performed in step S5. In part (26), it is determined that the error has stopped.
If it is confirmed in step S1 that the load and circuit at each place are normal, the process proceeds to step S2, where the fan motor (21a) is driven to rotate the combustion fan (21) and each solenoid valve (51) ( 52), the proportional valve (53) is opened, and the ignition electrode (16) is energized from the igniter to ignite the gas burner (2), and the combustion operation is started.
Subsequently, in step S3, the temperature control by the room temperature thermistor (27) is started, and in step S4, the fan motor (22a) is driven to rotate the convection fan (22), so that the instrument main body is rotated. (1) The hot air generated in the room is discharged into the room from the air outlet (20), and at the same time, the room air is taken into the apparatus body (1) from the air inlet (13). It is heated by circulation through the main body (1).

  During the circulation of room air, it is determined in step S6 whether or not the NOx sensor (5) has exceeded the reference value. If it is determined that the reference value has been exceeded, the process proceeds to the next step S7, where the room temperature Temperature control by the thermistor (27) is temporarily stopped, and in step S8, the solenoid valves (51) (52) and the proportional valve (53) are closed to stop the combustion of the gas burner (2). Accordingly, the rotation of the combustion fan (21) is stopped.

When the combustion of the gas burner (2) is stopped, the exhaust of the combustion exhaust is also stopped, so the amount of combustion exhaust leaked into the room from the instrument body (1) is reduced, and accordingly the NOx sensor (5) The detected NOx value (concentration) should decrease.
Therefore, in step S9, the concentration of nitrogen oxides by the NOx sensor (5) is detected again. The NOx value detected by the NOx sensor (5) is detected for about 30 seconds and the NOx value detected by the NOx sensor (5) does not change compared to the NOx value detected in step S6, that is, the NOx value does not decrease. In this case, the NOx sensor (5) does not react to the combustion exhaust leaking from the appliance body (1) as the hot air heater, but does not react with the combustion exhaust discharged from another combustion device installed in the same chamber. Can be judged to have responded. As a result, it is considered that there is little nitrogen oxide in the hot air blown out from the appliance body (1), so the process proceeds to step S10, where the fan motor (21a) is redriven and the combustion fan (21) rotates. When the solenoid valve (51) (52) and proportional valve (53) are opened, the combustion operation of the gas burner (2) is resumed by energizing the ignition electrode (16) from the igniter. In S11, the indoor air is circulated and heated until the temperature detected by the room temperature thermistor (27) reaches the set temperature.

  When the NOx value detected by the NOx sensor (5) decreases in step S9, the NOx value detected in step S6 is caused by the combustion exhaust leaking from the appliance body (1) as the hot air heater. Therefore, the process proceeds to step S12, where it is determined that the exhaust leakage is abnormal, and the drive of each part is stopped by an error in response to a command from the control part (26).

  In the CO sensor that was previously installed as an exhaust leak detection means, CO could be detected only after the gas burner (2) burned abnormally and high-concentration carbon monoxide was generated. In addition to reacting with nitrogen oxides, the NOx concentration contained in the combustion exhaust generated by the FF heater is higher than the CO concentration. react. As described above, since the appliance can be stopped before the abnormal combustion in which high concentration of carbon monoxide is generated, it is possible to provide a warmer air heater with higher safety.

The NOx sensor (5) may be provided on the back surface of the instrument body (1).
In this case, if the exhaust pipe (11) outside the instrument body (1) is damaged or abnormal, the location where the combustion exhaust leaks and the position of the NOx sensor (5) are close, so that the combustion exhaust leak is recognized earlier. can do.

・ ・ ・ ・ ・ ・ ・ Equipment body
(11) ... Exhaust pipe
(12) ... Air supply pipe
(13) ... Air intake
(15) ... Heat exchanger
(2) ・ ・ ・ ・ ・ ・ ・ Gas burner
(20) ...
(21) ... combustion fan
(22) ... Convection fan
(5) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ NOx sensor

Claims (2)

A supply / exhaust pipe that penetrates the wall and opens to the outside is connected to an appliance body provided with an intake port for taking in indoor air and an outlet through which hot air is blown out.
In the instrument body,
A gas burner, a heat exchanger that exchanges heat between combustion exhaust generated by the combustion of the gas burner and the room air, a combustion fan that sucks outdoor air through the air supply pipe and supplies the air to the gas burner, and A convection fan that blows indoor air taken into the appliance body into the room from the outlet as warm air after heat exchange with the heat exchanger;
In the hot air heater of forced air supply and exhaust type, the combustion exhaust after heat exchange is exhausted to the outside through the exhaust pipe,
A forced air supply / exhaust type hot air heater in which a NOx sensor is provided in the vicinity of the intake port as exhaust leakage detection means for detecting leakage of combustion exhaust from a heat exchanger, an exhaust pipe or the like.   The forced air supply / exhaust hot air heater according to claim 1, wherein when the NOx sensor detects a NOx concentration equal to or higher than a reference value during the combustion operation of the gas burner, the combustion of the gas burner is stopped and the combustion is stopped. The NOx concentration of the NOx sensor is measured again, and if the NOx concentration during combustion stop does not decrease compared to the concentration during combustion, the temperature of the forced supply / exhaust type having a controller that restarts the combustion of the gas burner and continues operation Wind heater.

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