JPH08121754A - Device for detecting concentration of unburnt component of combustion equipment - Google Patents

Abstract

PURPOSE: To constantly detect the concentration of the unburnt component with an excellent accuracy by avoiding the inconvenience attributed to the change of the detected value of the concentration of the unburnt component accompanying the temperature change. CONSTITUTION: A device for detecting the concentration of the unburnt component of a combustion equipment which is constituted so as to detect the concentration of the unburnt component contained in the exhaust gas passing through an exhaust passage L of a burner 3, and is provided with a CO sensor 17 where the output value is fluctuated based on the change of the atmospheric temperature, is provided with an atmospheric temperature keeping means B to keep the atmospheric temperature of the CO sensor 17 at the preset temperature or the value close to it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is configured to detect the concentration of unburned components contained in the combustion exhaust gas passing through the exhaust passage of a burner, and the output value of the unburned component based on a change in ambient temperature. The present invention relates to an unburned component concentration detection device for a combustion device, which is provided with a varying unburned component concentration detection means.

[0002]

2. Description of the Related Art An unburned component concentration detecting device for a combustion apparatus having the above structure detects the unburned component concentration in the combustion exhaust gas by the unburned component concentration detecting means, and the detected value is set in advance, for example. If it exceeds the upper limit, it is judged that the burner is incompletely burned, and by taking measures such as stopping the burner combustion and activating the alarm means, the state where the unburned component concentration is high becomes long. This is so that it can be prevented from continuing.

By the way, in the prior art, since the unburned component concentration detecting means has a characteristic that its output value fluctuates based on the change of the ambient temperature, the temperature detecting means for detecting the ambient temperature is used as the unburned component concentration. There is a configuration in which the output value of the unburned component concentration detection means is corrected based on the detected temperature and a predetermined temperature characteristic, which is arranged near the detection means.

[0004]

In the above conventional structure, the concentration of the unburned component can be detected relatively accurately when the ambient temperature is stable with a small amount of change. In the combustion device of
The ambient temperature in the exhaust passage constantly changes based on the change in the combustion state of the burner.

For example, in the case where the ambient temperature changes abruptly, due to the difference between the heat capacity of the unburned component concentration detecting means and the heat capacity of the temperature detecting means, the unburned component concentration detecting means accompanying the temperature change There is a possibility that a time lag may occur between the change in the detected value and the change in the temperature detected by the temperature detecting means.

As a result, in the case where there is a time lag in the detection state as described above, the detection value of the unburned component concentration (value after temperature correction) becomes a value that is significantly different from the accurate detection value. Sometimes, even if the actual unburned component concentration contained in the combustion exhaust gas is not large, the above detection value becomes a large value, for example, a problem such as determining that it is incomplete combustion occurs, etc. However, there was room for improvement in this respect.

The present invention avoids the inconvenience caused by the change in the detected value of the unburned component concentration due to the temperature change as described above, and can always detect the unburned component concentration with high accuracy. It is an object of the present invention to provide an unburned component concentration detection device for a combustion device that can be used.

[0008]

The features of the first invention are as follows:
An unburned component concentration detecting means configured to detect the concentration of the unburned component contained in the combustion exhaust gas passing through the exhaust passage of the burner and whose output value fluctuates based on a change in ambient temperature is provided. An unburned component concentration detecting device for a combustion apparatus, which is provided with an ambient temperature maintaining device for maintaining the ambient temperature of the unburned component concentration detecting device at or near a set temperature.

A characteristic configuration of the second aspect of the invention specifies a configuration suitable for carrying out the first aspect of the invention, wherein the ambient temperature maintaining means includes temperature detecting means for detecting the ambient temperature,
The detection value of the temperature detecting means is provided with a temperature adjusting means for adjusting the ambient temperature of the unburned component concentration detecting means so that the detected value is maintained at the set temperature or a temperature close to the set temperature. .

A characteristic configuration of the third invention is to specify a configuration suitable for carrying out the first or second invention, wherein a part of the unburned component concentration detecting means is connected to the exhaust passage. It is located inside the opened box-shaped body.

A characteristic configuration of the fourth invention is to specify a configuration suitable for carrying out the second or third invention, wherein the temperature adjusting means changes the supplied current value to change the ambient temperature. It is composed of an electrothermal heater for changing and adjusting the electric current and a current control means for controlling the electric current value supplied to the electrothermal heater based on the detection information of the temperature detecting means.

The characteristic configuration of the fifth invention is that the first, second, and third
Alternatively, the configuration suitable for carrying out the fourth aspect of the invention is specified, and the unburned component concentration detecting means is constituted by a catalytic combustion type CO sensor.

[0013]

According to the characterizing feature of the first invention, the ambient temperature of the unburned component concentration detecting means is maintained at or near the set temperature by the ambient temperature maintaining means irrespective of changes in the combustion state of the burner. Therefore, the detection value of the unburned component concentration detecting means does not change only due to the change of the ambient temperature.

According to the characterizing structure of the second invention, the following function is obtained in addition to the function of the characterizing structure of the first invention. By the temperature detecting means, the ambient temperature of the unburned component concentration detecting means is detected, and the ambient temperature is adjusted by the temperature adjusting means so that the detected temperature is maintained at or near the set temperature. The ambient temperature can be maintained at or near the set temperature.

According to the characteristic configuration of the third invention, the following operation is provided in addition to the operation of the characteristic configuration of the first or second invention.
Since the unburned component concentration detecting means is installed inside the box-shaped body, the combustion exhaust gas is directly installed in the exhaust path, and compared with the case where the unburned component concentration detecting means flows to the unburned component concentration detecting means. The internal temperature is unlikely to change, is less likely to be affected by the temperature of the combustion exhaust gas, and the ambient temperature can be easily maintained at or near the set temperature.

According to the characterizing feature of the fourth aspect of the invention, there are the following effects in addition to the effects of the characterizing feature of the second or third aspect of the invention.
By controlling the current value supplied to the electric heater,
Since the ambient temperature of the unburned component concentration detecting means is maintained at or near the set temperature, accurate temperature adjustment with excellent responsiveness can be performed with a relatively simple configuration.

According to the characterizing feature of the fifth aspect of the invention, the following effect is obtained in addition to the effect of the characterizing feature of the first, second, third or fourth aspect. As an unburned component in the combustion exhaust gas, the concentration of carbon monoxide (CO), which has a high possibility of adversely affecting the human body, will be detected.

Further, it is generally known that the catalytic combustion type CO sensor has a deteriorated detection capability due to simultaneous attachment of a sulfur component and water in the combustion exhaust gas.
By setting the set temperature to a temperature equal to or higher than the dew condensation temperature of water, it is possible to prevent dew condensation of water and suppress deterioration.

[0019]

According to the characterizing feature of the first aspect of the invention, since the ambient temperature does not fluctuate greatly, the fluctuation of the output value due to the temperature change is reduced, and it is not necessary to correct the output value, and the exhaust passage Even if the internal temperature suddenly changes, it is possible to always obtain the detection value corresponding to the actual unburned component concentration.

According to the characterizing structure of the second invention, in addition to the effect of the characterizing structure of the first invention, there are the following effects. Since the ambient temperature of the unburned component concentration detecting means can be reliably maintained at the set temperature or a temperature close thereto, it is possible to obtain the detected value corresponding to the actual unburned component concentration with a small error.

According to the characterizing structure of the third invention, the following effect is obtained in addition to the effect of the characterizing structure of the first or second invention.
The ambient temperature can be easily maintained at or near the set temperature, and the temperature error can be reduced. In addition,
When the temperature adjusting means is provided, there is an advantage that the adjustment range by the temperature adjusting means is small.

According to the characterizing structure of the fourth invention, the following effect is obtained in addition to the effect of the characterizing structure of the second or third invention.
For example, compared to a configuration in which heat is exchanged while flowing a heat medium to adjust the temperature, a simple control configuration allows
The ambient temperature can be maintained at or near the set temperature.

According to the characterizing feature of the fifth invention, the following effect is obtained in addition to the effect of the characterizing feature of the first, second, third or fourth invention. By monitoring the concentration of carbon monoxide (CO), it is possible to improve the safety in use, and it is possible to prevent deterioration of the ability to detect the concentration of unburned components. .

[0024]

Embodiments will be described below with reference to the drawings. FIG.
FIG. 1 shows a hot water supply device as an example of the combustion device according to the present invention. This hot water supply device includes a hot water supply unit A, a control unit H that controls the operation of the hot water supply unit A, and a remote control device R that issues control information to the control unit H.

The hot water supply unit A includes a heat exchanger 2 for heating water and a burner 3 for heating the heat exchanger 2 in the combustion chamber 1, and the burner 3 burns in the combustion chamber 1. Ventilation air is passed and the combustion exhaust gas from the burner 3 is transferred to the combustion chamber 1
A fan 5 is provided as a ventilating means for exhausting the air through the exhaust pipe 4 to the outside of the room.

The heat exchanger 2 is connected to a water supply passage 7 for supplying water and a hot water supply passage 8 for supplying heated hot water to a hot water tap (not shown), and the water supply passage 7 is connected to the heat exchanger. An inlet water temperature sensor 9 for detecting the inlet water temperature to the heat exchanger 2 and a water amount sensor 10 for detecting the amount of water supplied to the heat exchanger 2 are provided, and a hot water outlet 8 for detecting the outlet water temperature of the heat exchanger 2 is provided in the hot water supply passage 8. A temperature sensor 11 is provided.

The fuel gas supply passage 12 for the burner 3 is provided with an opening / closing valve 13 for connecting and disconnecting the fuel gas supply and an electromagnetic gas amount adjusting valve 14 for adjusting the fuel gas supply amount.
An igniter 15 for ignition and a frame rod 16 for detecting whether or not the burner 3 has ignited are provided near the burner 3. Although not shown, an abnormal high temperature sensor or the like for detecting that the heat exchanger 2 has an abnormally high temperature due to, for example, being heated in the air is provided near the heat exchanger 2.

Further, in the exhaust passage L through which the combustion exhaust gas of the burner 3 passes, it serves as an unburned component concentration detection means for detecting the concentration (CO concentration) of carbon monoxide contained in the combustion exhaust gas as an unburned component. A catalytic combustion type CO sensor 17 is provided.

As shown in FIG. 2, the CO sensor 17 includes a sensor element 32, a temperature compensating reference element 33, and a pedestal 31 inside a protective frame 30 made of stainless steel.
A temperature sensor 34 is provided as a temperature detecting means for detecting the ambient temperature of the CO sensor 17. The sensor element 32 and the temperature compensating reference element 33 are each made of platinum carrying a catalyst, and the sensor element 32,
As shown in FIG. 3, the temperature compensating reference element 33 and the two resistance elements 35 and 36 are connected in a bridge circuit state. Then, the sensor element 32 and the temperature compensating reference element 33 are heated by the flow of current, and the unburned components in contact with the surfaces thereof are burned by the catalytic action. At this time, since the catalyst carried by the sensor element 32 has selectivity for carbon monoxide, a difference occurs in element temperature between the sensor element 32 and the temperature compensating reference element 33. Since 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 sensor element 32 and the temperature compensation reference element 33. Therefore, the output value according to the CO concentration in the combustion exhaust gas is determined by the sensor element 32 in the bridge circuit.
And a connection portion between the temperature compensating reference element 33, and
It is configured to be output from the connection portion with the resistance elements 35 and 36. Further, the CO sensor 17 has a characteristic that its output value varies in a non-linear state based on a change in ambient temperature even if the CO concentration is the same.

The CO sensor 17 has an exhaust passage L through the opening 18 in the exhaust passage L through which combustion exhaust gas passes.
It is installed inside the box-shaped body 19 which is partially opened so as to communicate with the. A guide plate 20 for effectively guiding the combustion exhaust gas flowing upward to the inside of the box-shaped body 19 is provided at a position close to the opening 18 of the exhaust path L.

Further, an atmosphere temperature maintaining means B for maintaining the atmosphere temperature of the CO sensor 17 at or near a set temperature is provided. More specifically, an electric heater 37 capable of changing and adjusting the ambient temperature of the CO sensor 17 is provided inside the box-shaped body 19, and a control unit H as current control means sets a detection value by the temperature sensor 34. The current value supplied to the electric heater 37 is ON / OFF controlled so as to be maintained at or near the temperature. Therefore, the electric heater 37 and the control unit H constitute the temperature adjusting means C, and the temperature adjusting means C and the temperature sensor 34 constitute the ambient temperature maintaining means B.

The remote controller R has an operation switch 23 for instructing start / stop of operation, a temperature display section 24 for displaying the hot water supply temperature, and a temperature setting switch 2 for setting a target hot water supply temperature.
5, an operation lamp 26 for displaying whether or not it is in an operating state, and an abnormality display lamp 2 that lights up when an abnormal state described later occurs
7 etc. are provided.

The control unit H includes the sensors 9, 10, 11 described above.
Based on the detection information of the flame rod 16 and the flame rod 16, the gas amount control valve 1 is controlled so that the combustion of the burner 3 becomes a proper combustion state.
4, combustion control for controlling the fan 5 and the like, temperature control for controlling the ambient temperature of the CO sensor, and if the CO concentration detected by the CO sensor exceeds the set upper limit value and incomplete combustion is determined, the burner combustion is stopped. It is configured to execute control such as safe operation control for stopping.

The control operation of the controller H will be described below with reference to the control flowcharts shown in FIGS. When the power is turned on, the electric heater 37 is energized to heat the inside of the box-shaped body 19 (step 1). And even while the operation switch 23 is not turned on,
Temperature control is executed to control the current value supplied to the electric heater 37 so that the atmospheric temperature of the CO sensor 17 is maintained at or near the set temperature (step 2,
3). Specifically, the detected value T of the temperature sensor 34
When x exceeds 190 ° C, energization to the electric heater 37 is stopped, and when it falls below 170 ° C, energization to the electric heater 37 is started, and the ambient temperature of the CO sensor 17 is changed to
The temperature is controlled to be maintained at or near the set temperature (180 ° C).

After the power is turned on, the electric heater 3
If the detected value Tx of the temperature sensor 34 is not within the range of 180 ± 20 ° C. even after the time T ₁ (10 minutes) required for the initial heating by 7 has passed, it is determined that there is an abnormality, and the abnormality display lamp 27 is turned on (step 4,
5, 6). The detection value Tx of the temperature sensor 34 is 180 ± 20
If it is within the range of ° C, the power supply to the electric heater 37 is stopped and the operation standby state is set (step 7).

Then, even if the operation switch 23 is turned on by the time the required time T ₁ elapses after the power is turned on, the temperature sensor 34 detects after the required time T ₁ elapses. If the value Tx is not within the range of 180 ± 20 ° C, it is determined that there is an abnormality, and the abnormality display lamp 27 is turned on (steps 8, 9, 10), and the detected value Tx of the temperature sensor 34 is 180 ± 20 ° C. If it is within the range, the power supply to the electric heater 37 is stopped and the operation standby state is set (step 11).

When it is determined that the water flow amount detected by the water amount sensor 10 exceeds the set amount and the hot water tap is opened, the fan 5 starts the ventilation operation, and the CO sensor 1
The energization of 7 is started and the energization of the electric heater 37 is started (steps 12 to 15). Then burner 3
Ignition control is executed (step 16). That is, when the igniter 15 ignites the burner 3 and the flame rod 16 confirms ignition, the ignition operation is stopped.

When combustion is started, combustion control is executed to control the burner 3 to an appropriate combustion state so that the hot water supply temperature becomes the target hot water supply temperature (step 17). That is, the feedforward operation amount is determined based on the deviation between the target hot water supply temperature set by the temperature setting switch 25 and the incoming water temperature detected by the incoming water temperature sensor 9, and the amount of water supplied by the water amount sensor 10. Along with the calculation, the feedback operation amount is obtained based on the deviation between the target hot water supply temperature and the detected value of the hot water temperature sensor 11, and the gas amount control valve 14 is operated and controlled based on the added value of each operation amount to control the gas amount. In addition, the number of rotations of the fan 5 is controlled so that the amount of ventilation is suitable for the amount of gas.

Further, during the combustion operation, the temperature control is executed together with the above-mentioned combustion control (step 18).

If the time T ₂ (40 seconds) required for the initial heating of the CO sensor 17 has passed and the detected value Tx of the temperature sensor 34 is within the range of 180 ± 20 ° C., the CO sensor 17 The CO concentration measurement is performed (steps 19, 20, 21). If the detected value Tx of the temperature sensor 34 is not within the range of 180 ± 20 ° C., the time T required for the heating operation by the electric heater 37 to stabilize is T.
_{After 4} (5 minutes) has passed, the detection value of the temperature sensor 34 is checked again, and if it is within the range of 180 ± 20 ° C, the CO concentration is measured by the CO sensor 17, and the required time T ₄ The timer for time is cleared (steps 22, 23, 24). During the recheck, if the detected value Tx is not within the range of 180 ± 20 ° C, it is determined that there is an abnormality, the abnormality display lamp 27 is turned on, and the combustion of the burner 3 is stopped (steps 25 and 26).

As described above, the measurement of the CO concentration by the CO sensor 17 is executed under the condition that the ambient temperature is always within the range of 180 ± 20 ° C., and the output value due to the change of the ambient temperature is measured. We try to minimize fluctuations.

Then, for example, the CO concentration detected by the CO sensor 17 exceeds the set upper limit value, the flame cannot be confirmed by the frame rod 16 despite the combustion operation, or the heat exchanger is detected by the abnormal high temperature sensor. If there is an operation abnormality such as when the abnormal high temperature of 2 is detected (step 27), the abnormality display lamp 27 is turned on and the burner 3 is turned on.
Is stopped (steps 28 and 26).

When the operation is normal and the detected value of the water amount sensor 10 falls below the set value due to the closing operation of the hot water tap, the fuel supply to the burner 3 is stopped to stop the combustion, and the post purge is executed. After that, the operation of the fan 5 is stopped and the energization of the CO sensor 17 is stopped (step 2).
9-33).

Even after the energization of the CO sensor 17 is stopped, the temperature control is executed, the temperature inside the box-shaped body 19 is drastically lowered, and dew condensation occurs, so that the CO sensor 17 becomes a sulfur component. The deterioration due to the condensed water is prevented (step 34). Then, the required time T ₃ for preventing dew condensation
After (30 minutes) has elapsed, the power supply to the electric heater 37 is stopped (steps 35 and 36).

[Other Embodiments] (1) In the above embodiment, as temperature adjusting means for adjusting the ambient temperature of the CO sensor, temperature control is performed by a state in which the electric heater is energized and an ON / OFF control in which the energization is stopped. However, the temperature may be adjusted by changing and controlling the supplied current value. Further, as the temperature adjusting means, instead of using an electric heater, a structure in which a high-temperature heat medium is flow-supplied in a cylindrical heat exchanger, and the detection value of the temperature sensor becomes a set temperature or a temperature close thereto Thus, the temperature of the heat medium supplied may be adjusted.

(2) In the above embodiment, as the ambient temperature maintaining means, the temperature detection means (temperature sensor) for detecting the ambient temperature of the CO sensor maintains the detected value at or near the set temperature. Although the temperature adjusting means is controlled, for example, a high temperature heating medium is fluidized and supplied into a cylindrical heat exchanger arranged near the CO sensor, and the temperature of the heating medium is set to the temperature of the CO sensor. The ambient temperature of the CO sensor may be maintained constant at a preset temperature so that the ambient temperature is maintained at or near the preset temperature. In short, the ambient temperature of the CO sensor is maintained at or near the preset temperature. I wish I had it.

(3) In the above embodiment, the case where the catalytic combustion type CO sensor is used as the unburned component concentration detecting means is exemplified, but instead of this, various sensors such as an O ₂ sensor and a CO ₂ sensor are used. Applicable in case.

(4) In the above embodiment, the hot water supply device is illustrated as an example of the combustion device, but the invention can be applied to various combustion devices such as a combustion operation for heating and a combustion device for cooking.

It should be noted that reference numerals are added to the claims for facilitating the 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 schematic configuration diagram of a hot water supply device.

FIG. 2 is a schematic side view of a CO sensor.

FIG. 3 is a circuit configuration diagram of a CO sensor

FIG. 4 is a flowchart of control operation.

FIG. 5 is a flowchart of control operation

[Explanation of symbols]

 3 burner 17 unburned component concentration detecting means 19 box-like body 34 temperature detecting means 37 electric heater B atmosphere temperature maintaining means C temperature adjusting means H current control means L exhaust path

Claims (5)

[Claims] 1. A burner (3) is configured to detect the concentration of an unburned component contained in a combustion exhaust gas passing through an exhaust passage (L), and the output value of the unburned component is determined based on a change in ambient temperature. An unburned component concentration detection device for a combustion device, which comprises a varying unburned component concentration detection means (17), wherein the ambient temperature of the unburned component concentration detection means (17) is a set temperature or a temperature close to the set temperature. An unburned component concentration detecting device for a combustion device, which is provided with an ambient temperature maintaining means (B) for maintaining. 2. The ambient temperature maintaining means (B) maintains a temperature detecting means (34) for detecting the ambient temperature, and a detected value of the temperature detecting means (34) at or near the set temperature. The unburned component concentration detecting device for a combustion apparatus according to claim 1, further comprising: a temperature adjusting unit (C) that adjusts an ambient temperature of the unburned component concentration detecting unit (17). 3. The unburned component concentration detecting means (17) comprises:
The unburned component concentration detection device for a combustion device according to claim 1 or 2, which is installed inside a box-shaped body (19) which is partially opened in a state of being connected to the exhaust passage (L). 4. The temperature adjusting means (C) is based on an electric heater (37) for changing and adjusting the ambient temperature by changing a supplied current value, and detection information of the temperature detecting means (34). And a current control means (H) for controlling a current value supplied to the electric heater (37). 5. The unburned component concentration detecting means (17) comprises:
3. A contact combustion type CO sensor.
The unburned component concentration detecting device of the combustion device according to 3 or 4.