JP3744618B2 - Combustion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion apparatus such as a water heater or a bath tub, and more specifically, an FF type (forced supply) equipped with a carbon monoxide gas sensor (hereinafter referred to as a CO sensor) that detects a carbon monoxide gas concentration that exceeds a predetermined concentration. The present invention relates to safety detection means in a water heater.
[0002]
[Prior art]
Generally, various safety devices for safety measures are attached to a combustion device such as a water heater. For example, when the flame of the burner disappears or lifts, the safety device is a falling safety device that stops combustion instantaneously by the frame rod, in the event that it becomes empty or the heat exchanger is clogged with fins There is an overheat prevention device that shuts off the gas by closing the gas solenoid valve with a thermal fuse, etc., and an overpressure release device that activates the blow valve to release the pressure when the pressure in the heat exchanger rises abnormally In addition, when the CO sensor detects that the carbon monoxide (CO) concentration in the exhaust gas has reached a set value or more due to incomplete combustion, control such as stopping the combustion is performed.
[0003]
In addition, a hot water heater referred to as an FF type hot water heater is provided with a combustion fan that is controlled so as to supply an optimum air volume corresponding to the combustion at that time so as not to cause incomplete combustion in an air supply passage or an exhaust passage. ing. Further, in combination with the CO sensor, the rotation of the combustion fan can be controlled so as to minimize the CO value generated during combustion. Thereby, efficient supply / exhaust becomes possible, and incomplete combustion can be minimized.
[0004]
Exhaust gas generated by such combustion is exhausted from the combustion chamber to the outside through the exhaust passage. However, if there is a hole in the exhaust passage on the downstream side of the combustion chamber, for example, in the instrument due to corrosion, damage to parts, poor sealing or disconnection of the connection, etc. The part leaks into the combustion device through the hole of the exhaust passage before being discharged outside the room. Exhaust gas that has leaked into the combustion apparatus is very dangerous, particularly when the combustion apparatus is installed in a room, because the leaked exhaust gas further leaks into the room.
[0005]
In order to prevent such a danger, a thermal fuse installed in the combustion apparatus has been conventionally used. Since the exhaust gas is hot, when it leaks into the combustion apparatus, safety measures have been taken such as detecting a temperature rise in the combustion chamber and stopping the combustion when the temperature reaches a predetermined temperature or higher.
[0006]
[Problems to be solved by the invention]
However, the thermal fuse is usually provided in the vicinity of the combustion chamber, and is not suitable for temperature detection near the exhaust passage, for example. Even in the vicinity of the combustion chamber, the detection capability may vary depending on the distance between the hole position and the thermal fuse position.
[0007]
Therefore, a detection means for accurately detecting that a hole has been formed in the combustion apparatus is required, and an object of the present invention is to provide the means.
[0008]
[Means for Solving the Problems]
An object of the present invention is to provide a burner, a combustion fan that supplies and exhausts air to the burner, an air supply passage, an exhaust passage, and a CO that detects the CO concentration in the exhaust gas provided in the exhaust passage. In a combustion apparatus equipped with a concentration detector,
This is achieved by providing a combustion apparatus having holes in the supply passage for sucking air in the combustion apparatus.
[0009]
That is, the air supply passage generally sucks only air from outside the room by the rotation of the combustion fan. However, if a hole is made in the air supply passage in the combustion chamber, the air supply passage combusts together with the outdoor air. It also sucks indoor air. Here, when a hole is formed in the combustion chamber or the exhaust passage for some reason, and the exhaust gas leaks from the hole into the combustion apparatus, the exhausted gas is included in the sucked air in the combustion chamber.
[0010]
The air in the combustion apparatus containing the exhaust gas has an oxygen concentration lower than that of the outdoor air because it contains exhaust gas having a low oxygen concentration. When combustion is performed with air having a low oxygen concentration, the gas undergoes incomplete combustion and CO gas is generated.
[0011]
A CO sensor for detecting the CO concentration is installed in the exhaust passage, and as described above, the rotation of the combustion fan is controlled based on the detected CO gas concentration, and when the concentration reaches a predetermined level or more. Control is performed so that combustion is stopped.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to this embodiment.
[0013]
FIG. 1 is a diagram illustrating a configuration of a water heater 1 according to the present embodiment. When a hot water tap (not shown) is opened, the water passes through the water amount sensor 10 and is branched into the hot water supply heat exchanger 16 and the bypass passage 14. The hot water heated by the hot water supply heat exchanger 16 and the water passed through the bypass passage 14 are mixed to reach a set temperature and flow to the hot water tap.
[0014]
First, when the amount of water reaches a certain level, the water amount sensor 10 senses the flow rate. Then, the combustion fan 24 that sucks air from the air supply passage 50 and exhausts the exhaust gas after combustion from the exhaust passage 52 rotates, and pre-purge starts. In the present embodiment, the combustion fan 24 is installed in the exhaust passage 52. This is because the exhaust gas is uniformly dispersed in the exhaust passage and the CO sensor described later is operated accurately.
[0015]
Subsequently, when the ignition plug 18 is ignited, the original gas solenoid valve 28 and the gas solenoid valve 30 are opened, and gas flows through the gas proportional valve 32.
[0016]
Next, when the burner 22 is ignited, the flame rod 20 detects a flame and starts combustion. When ignition does not occur within a predetermined time, the safety circuit is activated, the original gas solenoid valve 28 and the gas solenoid valve 30 are shut off, and the discharge is also stopped. When the hot water temperature changes due to changes in the amount of hot water, amount of water, water pressure, etc. while using hot water, the incoming thermistor 34, outgoing hot water thermistor 36, and the water amount sensor 10 detect and calculate the set temperature difference with the outgoing hot water temperature, incoming water temperature, and water volume Then, the gas proportional valve 32 and the water amount control valve 38 are controlled by feedback control or the like, and the set temperature is maintained.
[0017]
The combustion fan 24 is provided with a Hall IC 26 that detects the rotational speed of the fan, and the rotation of the combustion fan 24 sends an optimal air volume to the burner 22 so as to cause complete combustion in accordance with the amount of gas supplied. Is controlled.
[0018]
A CO sensor 40 is installed in the exhaust passage. The CO sensor 40 is generally composed of a platinum resistor having a specific catalyst that chemically reacts with the CO gas. The catalyst causes a chemical reaction with the CO gas, and the temperature of the catalyst rises. The resistance value of the platinum resistance that changes in response to the temperature change is compared with the comparison element, and is converted into a CO concentration.
[0019]
When the CO gas concentration is detected by the CO sensor 40 above the allowable value, first, the rotational speed of the combustion fan 24 is increased, and the rotational speed of the combustion fan is set so that complete combustion is performed by increasing the amount of air sent into the combustion chamber. Is controlled. However, even if the air volume is increased, the combustion is stopped when the CO gas concentration does not decrease and reaches a predetermined concentration or more.
[0020]
The present invention uses the CO sensor to detect that a hole has been formed in the exhaust passage in the appliance after the combustion chamber. Therefore, in the present embodiment, a hole 60 having an appropriate size is formed in the air supply passage 50. There may be multiple holes, and by making multiple holes, it becomes possible to supply leaked exhaust gas at any position in the exhaust passage. It is preferable to focus on. When the hole 60 is formed in the air supply passage 50, the air supply passage 50 on the upstream side of the combustion fan has a negative pressure due to the rotation of the combustion fan 24. Therefore, the air supply passage 50 sucks air from the outside. In addition, air in the combustion apparatus 1 is also sucked from the drilled hole 60.
[0021]
If there is no hole in the exhaust passage 52, the exhaust gas does not leak. Therefore, the air in the combustion chamber sucked from the hole formed in the air supply passage 50 is the same component as the air sucked from the outside. Therefore, the same combustion as in the case where only the outdoor air is sucked and supplied is performed. However, for example, if a hole is formed in the exhaust passage 52 as in the hole 62 in the figure, the exhaust gas leaks from the hole, and the exhaust gas is sucked from the hole of the air supply passage 50. Since the exhaust gas has an oxygen concentration lower than that of normal air, when the exhaust gas is sucked from the hole formed in the air supply passage 50, the amount of air supplied is larger than when only the air from the outside is sucked. Oxygen concentration decreases.
[0022]
When combustion is performed by air having a low oxygen concentration, incomplete combustion is caused and the CO gas concentration is increased. The increased CO gas is detected by a CO sensor provided in the exhaust passage. When the CO gas is detected by the CO sensor, as described above, the rotation of the combustion fan increases in order to increase the air volume. However, the CO gas concentration does not decrease, and as soon as the total amount of CO generated is small, the CO gas concentration decreases. Combustion will be stopped.
[0023]
FIG. 2 is a diagram showing a configuration of a combustion apparatus according to another embodiment of the present invention. In the present embodiment, the combustion fan 24 is installed on the supply passage 50 side from the combustion chamber 42. In this case as well, as described above, the air in the combustion chamber can be sucked by making a hole in a part of the intake passage upstream from the position of the combustion fan 24, and the exhaust gas is leaking into the combustion chamber. Inhaling it can cause incomplete combustion and activate the CO sensor.
[0024]
The combustion apparatus of the present invention controls the combustion fan 24 so that the exhaust gas is exhausted as necessary and sufficiently after the combustion is stopped. Thereby, the exhaust gas is not discharged into the instrument from the hole provided in the air supply passage 50.
[0025]
【The invention's effect】
As described above, the present invention creates a hole in the air supply passage and sucks exhaust gas leaked from the hole in the exhaust passage, thereby causing incomplete combustion and detecting the generated CO gas with a CO sensor. It is a means for detecting that a hole has opened in the combustion apparatus. According to this means, the exhaust gas leaking into the combustion chamber is sucked by the negative pressure in the air supply passage, so that it does not matter which part in the combustion device the holed place is. Therefore, it is possible to accurately detect that a hole has opened in the combustion apparatus.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a combustion apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a combustion apparatus according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Combustion device 12 Water quantity sensor 14 Bypass passage 16 Hot water supply heat exchanger 18 Spark plug 20 Flame rod 22 Burner 24 Combustion fan 26 Hall IC
28 Original Gas Solenoid Valve 30 Gas Solenoid Valve 32 Gas Proportional Valve 34 Water Thermistor 36 Hot Water Thermistor 38 Water Volume Control Valve 40 CO Sensor 42 Combustion Chamber 50 Air Supply Passage 52 Exhaust Passage 60 Hole 62 Hole

Claims (1)

A combustion chamber, a combustion fan for supplying air to the combustion chamber and exhausting air from the combustion chamber are provided in the apparatus, an air supply passage provided between the combustion chamber and the outside of the chamber, and the combustion chamber An exhaust passage provided between the outside and a combustion apparatus installed indoors ,
A CO concentration detector provided in the exhaust passage for detecting the CO concentration in the exhaust gas;
The combustion apparatus further comprises a hole for sucking air in the combustion apparatus in an air supply passage in the combustion apparatus.

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