JPH07332666A - Combustion exhaust gas-detecting device for combustion equipment - Google Patents

Abstract

PURPOSE:To prevent a sensor from deteriorating due to the deposition of a sulfur component, etc., and to use combustion equipment for a long period of time by avoiding an energizing-heating type sensor such as a CO sensor, etc., from being exposed in a reduction type atmosphere under a high temperature condition as much as possible, for a combustion exhaust gas-detecting device such as a gas combustion type hot water feeding device, etc. CONSTITUTION:A combustion exhaust gas-detecting device for combustion equipment is equipped with an energizing-heating type sensor S which is arranged in a combustion gas of a burner 2 and detects the condition of the combustion exhaust gas, and a control means H which controls the combustion operation of the burner 2 and the detecting operation of the sensor S. Then, the control means H is formed in such a manner that an energizing to the sensor S may be started after the burner 2 is ignited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion exhaust gas detection device for detecting CO concentration and the like contained in exhaust gas after combustion in various combustion equipment such as a gas combustion type hot water supply device, and more particularly to burner combustion. Combustion exhaust gas detection device for combustion equipment provided with an electrically heating sensor arranged in exhaust gas for detecting the state of combustion exhaust gas, and control means for controlling combustion operation of the burner and detection operation of the sensor Regarding

[0002]

2. Description of the Related Art Conventionally, as a combustion exhaust gas detection device having such a structure, for example, in a gas combustion type hot water supply device, an electrically heating type CO sensor is arranged in the combustion exhaust gas of a burner,
It is known that when the CO concentration value detected by this CO sensor exceeds a certain value, the burner combustion is controlled to be stopped.

Regarding the control operation in this conventional device,
Briefly explaining based on the flowchart of FIG. 5, when the hot water tap is opened, heating water is supplied to the heat exchanger, and when the supply amount of the water reaches a certain amount as detected by the water amount sensor, the burner burns. A fan that supplies air for operation is driven. When the rotation of the fan reaches a predetermined number of rotations, an electromagnetic proportional valve or the like for supplying the fuel gas to the burner is opened and the igniter ignites the burner to start combustion.
Energization of the sensor is started. After this energization, the flame of the burner is detected by the frame rod and the like, the operation of the igniter is stopped, and the heating of the CO sensor is completed.
When the CO concentration is detected by the O sensor and the CO concentration exceeds the set value, the combustion of the burner 2 is stopped.

[0004]

As described above, in the conventional combustion exhaust gas detection device, after the energization of the energization heating type sensor is performed, the flame is detected by the frame rod or the like, that is, the burner is ignited. Has been detected,
There were the following problems.

That is, in the energization heating type sensor, the temperature reaches the detection temperature in about 2 seconds after the energization, and the detection temperature is, for example, C using a platinum wire tangled with a catalyst.
The temperature of the O sensor is about 200 ° C., which is a considerably high temperature.

Therefore, in the conventional device for detecting the ignition of the burner after energization, there is a possibility that the high-temperature energization heating type sensor is exposed to the reducing atmosphere in which the ignition is insufficient and the combustion is incomplete. However, when the high-temperature sensor is exposed to the reducing atmosphere, sulfur in the unburned gas is deposited and adheres to the sensor, which may cause deterioration of the sensor.

[0007] The present invention is to eliminate the above-mentioned conventional drawbacks, and to prevent the deterioration of the high temperature electric heating type sensor by avoiding exposure to the reducing atmosphere as much as possible. However, the purpose is to enable long-term use.

[0008]

In order to achieve this object, a first characteristic configuration of a combustion exhaust gas detecting apparatus according to the present invention is a control means for controlling a combustion operation of a burner and a detection operation of an electric heating type sensor. However, it is configured to start energizing the sensor after igniting the burner.

A second characteristic configuration is that the sensor is a catalytic combustion type CO sensor for detecting the CO concentration in the combustion exhaust gas.

A third characteristic structure is provided with ignition means for igniting the burner and flame detecting means for detecting a flame formed by the burner, and the control means operates the ignition means. The flame detecting means is configured to judge that the burner is ignited when the flame is detected.

A fourth characteristic configuration is that the control means is configured to start energization of the sensor after a lapse of a fixed time after ignition of the burner.

[0012]

According to the first characteristic configuration of the present invention, the control means for controlling the combustion operation of the burner and the detection operation of the energization heating type sensor starts energizing the sensor after igniting the burner. Since the burner is configured to operate, it is extremely unlikely that the high-temperature electric heating type sensor is exposed to the reducing atmosphere in which the burner is insufficiently ignited and is in an incomplete combustion state. Therefore, it is less likely that sulfur or the like in the unburned gas will deposit and adhere to the sensor, and even if the temperature is raised to a temperature higher than the normal detection temperature for cleaning at the initial stage of the energization start, There is little risk that sulfur or the like will adhere and deteriorate, and it can be used for a long period of time.

According to the second characteristic configuration, the sensor is
Catalytic combustion type C for detecting CO concentration in the combustion exhaust gas
Since it is an O sensor, it is possible to more reliably detect whether or not the burner is incompletely burning, and when incomplete combustion is occurring, for example, stop the subsequent processing such as stopping the burner combustion. Can be done quickly.

According to the third characteristic configuration, ignition means for igniting the burner and flame detecting means for detecting a flame formed by the burner are provided, and the control means operates the ignition means. After that, since the flame detection means is configured to judge that the burner is ignited in accordance with the detection of the flame, normally, the flame detection means such as a flame rod provided in this type of combustion equipment is used. It can be used as it is, and the energization of the CO sensor can be started after the burner is surely ignited, and the deterioration of the CO sensor can be prevented with relative simplicity.

According to the fourth characteristic configuration, since the control means is configured to start energizing the sensor after a lapse of a certain time after the burner is ignited, the high temperature CO sensor is reduced. It is also possible to completely avoid exposure to the atmosphere. That is, when the energization is started immediately after the flame is detected by the flame detecting means, the energization can be started in a state where ignition is not completed for all the flame openings of the burner due to the arrangement position of the flame detecting means. Although there is also a possibility that the high temperature CO sensor can be operated without the possibility of starting the energization after a lapse of a certain time in consideration of the time when the ignition of all the flames is completed after the flame is detected by the flame detecting means. It is also possible to completely avoid exposure in a reducing atmosphere.

[0016]

As described above, according to the first characteristic configuration of the present invention, the high temperature electric heating type sensor is exposed in the reducing atmosphere, and the sulfur or the like in the unburned gas is deposited, so that the sensor There is little possibility that the sensor adheres to the surface and deteriorates, and this sensor can be used for a long period of time.

According to the second characteristic configuration, it is possible to more reliably detect whether or not the burner is incompletely burning, and when the incomplete burning is occurring, the subsequent processing is promptly performed. It can be carried out.

According to the third characteristic configuration, the flame detecting means such as a frame rod which is usually provided can be used to prevent deterioration of the CO sensor with relative simplicity.

According to the fourth characteristic configuration, the high temperature CO sensor is exposed to the reducing atmosphere by starting the energization in consideration of the time when the ignition of all the burners is completed. Can be avoided altogether.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a gas combustion type hot water supply device which is an example of a combustion device. This hot water supply device includes a water heater A, a control unit H as a control means for controlling the operation of the water heater A, and this control unit. The water heater A includes a controller C for sending a command signal to the H, and the water heater A is heated by the combustion chamber 1, a gas combustion type burner 2 arranged in the combustion chamber 1, and the burner 2. It comprises a heat exchanger 3 and a fan 4 for supplying combustion air to the burner 2.

The burner 2 is provided with an igniter 5 as an ignition means for igniting the burner 2 and a frame rod 6 as a flame detecting means for detecting a flame formed by the burner 2 after ignition of the burner 2. The igniter 5 and the flame rod 6 are provided and are connected to the combustion control means H1 of the control unit H. A gas supply passage 7 connectable to a gas supply pipe for general households is connected to the burner 2, and an on-off valve 8 for connecting and disconnecting the supply of fuel gas and a fuel for the burner 2 are connected to the gas supply passage 7. An electromagnetic proportional valve 9 for adjusting the gas supply amount is provided, and both valves 8 and 9 are also connected to the combustion control means H1.

The heat exchanger 3 is provided with a water supply passage 10 for supplying water for heating, and a hot water supply passage 11 for supplying hot water after being heated by the heat exchanger 3 to a hot-water tap or a bathtub (not shown). And are connected. Further, the water supply passage 10 is provided with a water amount sensor 12 for detecting the amount of water flowing through the water supply passage 10 and supplied to the heat exchanger 3, and the hot water supply passage 11 after heating. A thermistor 13 for detecting the temperature of hot water is provided, and the water amount sensor 12 and the thermistor 13 are provided.
Is also connected to the combustion control means H1.

In the exhaust passage 14 communicating with the combustion chamber 1,
A catalytic combustion type CO sensor S for detecting the concentration of CO in the combustion exhaust gas after the burner 2 burns is arranged.
The sensor S is connected to the combustion control means H1 as well as to the incomplete combustion determination means H2 of the control unit H, and the burner 2 is incomplete based on the CO concentration value detected by the CO sensor S. It is configured to determine whether or not combustion is occurring.

This CO sensor S, as shown in FIG.
It has a sensor element 16 attached to the pedestal 15 and a reference element 17 for temperature compensation.
17 is covered with a protective frame 18 with a mesh made of stainless steel, and the pedestal 15 is provided with a connector 19 to a lead wire connected to the control section H. Both the sensor element 16 and the reference element 17 are made of platinum wire tangled with a catalyst, and when heated by energization, unburned components in the combustion exhaust gas contacting the surface are burned by the catalytic action. In addition, a catalyst having a selectivity with respect to CO is tanned toward the sensor element 16.

Therefore, when heated by energization,
Since a temperature difference occurs between these elements 16 and 17 and the resistance value of the platinum wire changes depending on the temperature, the greater the CO concentration in the combustion exhaust gas, the greater the difference in resistance value between the elements 16 and 17. As shown in FIG. 3, both elements 16, 17 become larger.
The CO concentration in the combustion exhaust gas can be detected by detecting the difference in resistance between the two as the output V.

The controller C is configured to be communicable with the control unit H by wire or wirelessly. As shown in FIG. 1, the controller C is provided with an operation switch 20 for instructing the operation start of the hot water supply device and a hot water supply temperature. A temperature setting switch 21 to be set, an LED lamp 22 for displaying whether or not the hot water supply device is operating, an LED lamp 23 that is turned on when the burner 2 causes incomplete combustion, and the like are provided.

Next, the control operation of this hot water supply device will be described with reference to the flowchart of FIG. First,
When the operation of the hot water supply device is started by the operation switch 20 and the hot water supply plug (not shown) is opened, the water for heating is supplied from the water supply passage 10 to the heat exchanger 3, and the supplied amount is detected by the water amount sensor 12. When the supply amount reaches a constant amount, the fan 4 is driven, and when the rotation speed of the fan 4 reaches a predetermined rotation speed,
The intermittent valve 8 and the solenoid proportional valve 9 of the gas supply path 7 are opened to supply the fuel gas to the burner 2, and the igniter 5 ignites the burner 2 to start combustion.

In the combustion of the burner 2, the amount of gas supplied to the burner 2 is adjusted by adjusting the solenoid proportional valve 9, and the hot water supply passage 1
The temperature of the hot water from 1 is controlled to the temperature set by the temperature setting switch 21, and the hot water of the desired temperature is constantly supplied from the hot water supply passage 11 until the combustion of the burner 2 is stopped. It

After the ignition, when the flame rod 6 detects a flame, it is judged that the burner 2 has ignited, the operation of the igniter 5 is stopped, and the delay timer is started. Start energizing. The delay time by this delay timer is determined in consideration of the time until the flame rod 6 ignites all the flame openings of the burner 2 after detecting the flame, and is about 3 seconds in this embodiment.

The CO sensor S is energized for about the first 20 seconds so that the CO sensor S has a temperature of about 400.degree. C. and is cleaned, and thereafter, the CO sensor S is energized to have a detection temperature of about 200.degree. . Then, 40 seconds to 90 seconds after the energization, the CO concentration is detected by the CO sensor S, thereby avoiding an erroneous operation at the beginning of combustion of the burner 2, and during the CO concentration detection execution, The incomplete combustion discriminating means H2 discriminates whether or not the detected CO concentration is equal to or higher than a certain set value.

When the concentration of CO in the combustion exhaust gas is less than a set value, the hot water tap is closed and the water amount sensor 12
Combustion of the burner 2 is continued until the detected amount by is below the set amount. When it is determined that the CO concentration has exceeded the set value, the on / off valve 8 and the solenoid proportional valve 9 of the gas supply path 7 are closed to stop the combustion of the burner 2, and at the same time, the LED lamp 23 is turned on. , Inform the occurrence of incomplete combustion. After that, the energization of the CO sensor S is stopped, the fan 4 is driven at a predetermined rotation speed for a certain period of time to perform afterpurge, and the hot water supply control ends.

[Other Embodiments] In the previous embodiment, after the flame is detected by the frame rod 6, the energization of the sensor S is started after a lapse of a certain time, but after the flame of the frame rod 6 is detected. Alternatively, the power supply can be started immediately. In this case, after the flame rods 6 are located near the flame mouth of the burner 2 that is the last to be ignited or a plurality of flame rods 6 are arranged, all flame rods 6 detect flames. If the energization is started, it is possible to completely prevent the high temperature sensor S from being exposed to the reducing atmosphere even after a certain period of time has not elapsed.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire water heater.

FIG. 2 is a schematic diagram showing the structure of a CO sensor.

FIG. 3 is a graph showing changes in output value with respect to CO concentration of a CO sensor.

FIG. 4 is a flowchart showing a control operation.

FIG. 5 is a flowchart showing a control operation of a conventional structure.

[Explanation of symbols]

 2 burner 5 ignition means 6 flame detection means S sensor H control means

Claims (4)

[Claims] 1. A sensor (S) of an electric heating type which is arranged in the combustion exhaust gas of a burner (2) and detects the state of the combustion exhaust gas, and a combustion operation of the burner (2) and detection of the sensor (S). A combustion exhaust gas detection device for a combustion device, comprising: a control means (H) for controlling the operation, wherein the control means (H) ignites the burner (2), and then the sensor (S). Exhaust gas detection device for a combustion device configured to start energization of the device. 2. The combustion exhaust gas detection device for a combustion device according to claim 1, wherein the sensor (S) is a contact combustion type CO sensor for detecting a CO concentration in the combustion exhaust gas. 3. An ignition means (5) for igniting the burner (2) and a flame detection means (6) for detecting a flame formed by the burner (2) are provided, and the control means (H). Is configured to determine that the burner (2) is ignited when the flame detecting means (6) detects a flame after the ignition means (5) is activated.
Combustion exhaust gas detection device for the described combustion equipment. 4. The combustion device according to claim 3, wherein the control means (H) is configured to start energization of the sensor (S) after a lapse of a certain time after ignition of the burner (2). Flue gas detector.