JPH07113451B2 - Combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a combustion device that can be used, for example, in a water heater, a bathtub or the like.

<Prior Art and Its Problems> Ceramic heaters have been conventionally used as igniters in combustion devices that use petroleum as a fuel, for example, but they have been used only as the igniters, and the characteristics of ceramic heaters are utilized. In the past, no combustion device has been provided that has a role and a function other than that of an igniter at the same time.

Then, this invention makes it a subject to provide the combustion apparatus which also has the function other than the function as an igniter using the resistance-temperature characteristic which a ceramic heater has.

On the other hand, the combustion device is adjusted so that it is burned at an optimum air-fuel ratio depending on the purpose of use, but for example, in a combustor such as a refueling tank or a bath kettle, it is often burned when the air-fuel ratio exceeds 1. . However, in such a case, in the sensor where the transition range of the output with respect to the air-fuel ratio is at a low air-fuel ratio, the output change near the target optimum air-fuel ratio becomes slow, and there is a problem that good detection and control cannot be performed. . For example, an oxygen sensor that has a proven track record for automobiles has an output transition region when the air-fuel ratio is around 1, but this oxygen sensor is used as a sensor for a lubricator that is optimal when the air-fuel ratio is 1.3. There was a difficult problem to solve.

Therefore, the object of the present invention is to provide a sensor having an output transition region at an air-fuel ratio different from the target optimum air-fuel ratio,
The purpose of the present invention is to provide a combustion device capable of controlling combustion by using this. And this allows the adoption of low cost sensors and sensors with other favorable characteristics,
The result is to provide a preferred combustion device.

<Means for Solving the Problems> A combustion apparatus according to the present invention which solves the above problems includes a burner portion 11 inside a combustion can body 10 and a ceramic heater near the burner portion 11.
A combustion device that has 14 and a flame detector 15, and mixes the air from the blower fan 12 and the fuel from the fuel supply pipe 13 and burns them on the burner section 11. 14 is configured as an igniter when a voltage is loaded from a power source through an ignition switch 17, and a resistance detector circuit of the ceramic heater 14 is formed by connecting a resistance detector 18 to the off contact 17b side of the ignition switch 17. Configure
Also, by inputting a flame detection signal from the flame detector 15, the ignition switch 17 is switched to the off contact 17b side, and thereby the burner unit is controlled by the electric resistance value of the ceramic heater 14 input from the resistance detector 18. The first feature is to have a control unit 19 for controlling the combustion state of 11.

Further, the combustion apparatus of the present invention for solving the above-mentioned problems is a combustion can body.
A burner portion 51 and a combustion space 52 above the burner portion 51 are provided in the chamber 50, and a sensor 53 for detecting the air-fuel ratio of combustion is provided in a region of the combustion space 52.
And a combustion device having a control unit 59 for controlling combustion by the air-fuel ratio detected by the sensor 53, wherein the burner unit 51 has an air-fuel ratio of combustion as a whole in the combustion space 52. When the optimum air-fuel ratio is reached, the air-fuel ratio in the area where the sensor 53 is arranged is near the fiber area of the output of the sensor 53, and the mixing ratio of the fuel and air that passes in advance is arranged at the corresponding location of the sensor 53. The second characteristic is that they are different from each other.

<Operation> According to the combustion device having the first characteristic, the ceramic heater 14 constitutes an igniter when the ignition switch 17 is turned on by turning on the operation switch or the like, and the voltage from the power source is applied to the ceramic heater 14. It is loaded and heated. As a result, the mixed gas of fuel and air supplied onto the burner unit 11 is ignited and combustion is started. Then, when the combustion is started, the flame detector 15 detects the flame, and the flame detection signal is input to the control unit 19, which switches the ignition switch 17 to the off contact 17b side. . As a result, the ignition operation by the ceramic heater 14 is completed, and the electric resistance value of the ceramic heater 14 is changed to the off contact 17 this time.
It is detected by the resistance detector 18 via b, and this is input to the control unit 19. The controller 19 receives the input ceramic heater 14
The combustion state of the burner unit 11 is controlled based on the electric resistance value of the.

As described above, according to the first feature, the ceramic heater 14 acts as an igniter at the time of ignition, and when the ignition ends, the ceramic heater 14 is automatically switched to the sensor for detecting the combustion state. Combustion control is performed by the control unit 19 based on the input.

Therefore, according to the first feature, it is possible to perform ignition for combustion using one ceramic 14, and control the combustion state during combustion using the ceramic heater 14, that is, the blower fan 12 and the combustion supply. Can be controlled.

Further, according to the combustion device having the second characteristic, the burner portion is
Sensor 53 for the mixing ratio of fuel and air passing through each part of 51
By making it different from the place where it is placed and the other place, when the air-fuel ratio in the combustion space 52 becomes the optimum air-fuel ratio of combustion, the air-fuel ratio in the area where the sensor 53 is placed is the sensor 53 output. Since it is set in the vicinity of the transition region, changes in the air-fuel ratio when combustion is in the vicinity of the optimum air-fuel ratio can be accurately and quickly detected in the most sensitive detection region by the sensor 53. Therefore, the control by the control unit 59 associated with the air-fuel ratio detection can be performed accurately and quickly. In addition, since the transition range of the sensor 53 that detects the air-fuel ratio does not have to match the optimum air-fuel ratio for combustion, the type of sensor 53 is not limited, and at the optimum air-fuel ratio for combustion, the output changes slowly. However, it can be used sufficiently effectively. That is, a sensor having various characteristics or an inexpensive sensor can be used for combustion control.

<Embodiment> FIG. 1 is an overall configuration diagram showing a first embodiment of the device of the present invention, and FIG. 2 is a characteristic diagram of a ceramic heater.

A burner unit 11 is provided in the lower part inside the combustion can body 10 to provide a blower fan.
The air and fuel introduced from 12 and the combustion supply pipe 13 are mixed and burned through the flame holes 11a of the burner portion 11. Further, in the vicinity of the burner portion 11 in the can body 10, a ceramic heater 14
And a flame detector 15 are provided. A heat exchanger 16 is provided in the upper part inside the can body 10 so that it can be used as a water heater or a bath.

The ceramic heater 14 is designed to be loaded with a voltage from a power source through an ignition switch 17, and is configured to function as an igniter. Further, a resistance detector 18 is connected to the OFF contact 17b side of the ignition switch 17 to form a resistance detection circuit for the ceramic heater 14. Further, the ignition switch 17 can switch the contact to the OFF contact 17b via the control unit 19 when the flame detector 15 detects the flame.

To further explain the contents of the device together with the operation, when an operation switch (not shown) is turned on, the fan 12 is rotated via the control unit 19, fuel is supplied from the fuel supply pipe 13, and the ignition switch 17 is turned on, The ceramic heater 14 is heated. As a result, fuel gas is ignited from the burner portion 11 and a flame F is formed. Due to the formation of the flame F, a flame detection signal from the flame detector 15 enters the control unit 19, and the ignition switch 17 is switched to the off contact 17b. By this switching, the resistance of the ceramic heater 14 can be detected by the resistance detector 18, and the ceramic heater 14 during combustion can be detected.
The electric resistance value of is input to the control unit 19. Based on the input electric resistance value, the control unit 19 outputs a rotation speed adjustment command to the blower fan 12. That is, since the electric resistance of the cetamic heater 14 changes depending on the temperature, the heating temperature of the ceramic heater 14 when it is burned at various air-fuel ratios m is obtained in advance as experimental data. From the temperature-resistance characteristics, the relationship between the resistance value Ω and the air-fuel ratio m can be obtained as shown in FIG.
Therefore, the current air-fuel ratio m can be obtained from the resistance value obtained by the resistance detector 18 in the control unit 19, and the size of the target air-fuel ratio m can be compared. Then, a rotation speed change command can be output to the blower fan 12 in order to further adjust the air amount in the direction of reducing the difference. Of course, the fuel supply amount may be adjusted by the control unit 19 or both the fuel and air may be adjusted. By doing so, it is possible to manage and control the combustion state. Further, as a form of management and control of the combustion state, the presence or absence of combustion itself can be detected and managed in addition to the detection and adjustment of the air-fuel ratio, excess and deficiency of air, and excess and deficiency of fuel.

FIG. 3 is an overall configuration diagram showing a second embodiment of the device of the present invention, and FIG. 4 is a characteristic diagram of the sensor.

A burner portion 51 is provided in the combustion can body 50, and a combustion space 52 is located above the burner portion 51. An oxygen sensor 53 is provided in a part of the combustion space 52 and above the burner portion 51. A heat exchanger 54 is provided above the combustion space 52 so that water can be heated as a water heater or a bath. Of the flame formed on the upper surface side of the burner portion 51, the air of the flame F ₁ in the space area in which the oxygen sensor 53 is arranged-
The fuel ratio, that is, the air-fuel ratio is adjusted so that the air-fuel ratios of the flames F ₂ and F _{3 in} the other space regions are different. That is, when the entire spread is being performed at the target optimum air-fuel ratio at that position, the air-fuel ratio of the space region in which the oxygen sensor 53 is arranged corresponds to the output transition region of the oxygen sensor 53. Adjust so that Explaining with a specific numerical example, for example, when the oxygen sensor 53 is in the transition region of the output at the air-fuel ratio = 1, when the optimum air-fuel ratio of the target device is 1.3, The air-fuel ratio in each part of the combustion space may be adjusted so that the air-fuel ratio near the oxygen sensor 53 becomes 1.0 when the fuel ratio becomes 1.3. In this case, as means for adjusting the air-fuel ratio of the flame F ₁ near the oxygen sensor 53,
The main flame F ₂ and the supplementary flame F ₃ can be used. That is, when the air-fuel ratio of the entire combustion is 1.3, the air-fuel ratio is 1.0 and the mixed gas for forming the main flame exceeding 1.0 and the mixed gas for forming the auxiliary flame with an air-fuel ratio of less than 1.0 are mixed. To form a mixed gas of. Explaining this concrete structure further, the air of the blower fan 55 and the fuel from the fuel supply source (not shown) are in the first mixing adjustment chamber of the can body 50.
It is sent to 56, and one part is sent to the 2nd mixing adjustment chamber 57 through the branch path 58. The mixed gas in the first mixing adjustment chamber 56 is adjusted to a value of air-fuel ratio> 1.0 for forming the main flame F ₂ .
The burner portion 51 is burned by passing through the portion where the flame holes 51a are densely formed. Further, the mixed gas in the second mixing adjustment chamber 57 is adjusted to a value of air-fuel ratio <1.0 for forming the supplementary flame F _3, and passes through a portion where the flame hole 51a of the burner portion 51 is roughly formed. Is burned. By thus forming the main flame F ₂ and the supplementary flame F ₃ filling the space between them, the flame is stable and blowout can be prevented. Then, in the burner portion 51 in the region where the oxygen sensor 53 is arranged, the first mixing adjustment chamber 56
Gas from both chambers of the second and second mixing adjustment chambers 57 is flowed at an appropriate ratio, and when the air-fuel ratio of the entire flame is 1.3, the detection flame F
Adjust so that the air-fuel ratio of ₁ is 1.0. The oxygen sensor
The detection output of 53 is input to the control unit 59 and the blower fan 55
Is output as a blow rate adjustment signal.

To explain further together with the operation, when an operation switch (not shown) is turned on, the blower fan 55 is controlled via the controller 59.
Is rotated, fuel is supplied, an igniter (not shown) performs an ignition operation, and combustion is started. Oxygen sensor during combustion
The output from 53 is monitored by the controller 59. The output-air-fuel ratio characteristic of the oxygen sensor 53 has a transition region near the air-fuel ratio of 1.0, as shown in FIG. Therefore, when the output of the oxygen sensor 53 is high, the rotation speed of the blower fan 55 is increased via the control unit 59, and when the output is low, the rotation speed of the blower fan 55 is decreased, which causes the oxygen sensor 53 to rotate. Is controlled so that the air-fuel ratio is 1 in the arrangement region, that is, the optimum combustion state of the entire device is 1.3. Of course, the blower fan 55
Instead of adjusting the air supply amount by the method described above, the fuel supply amount may be adjusted or both of them may be adjusted at the same time.

The above numerical values are not limited to this. In short, in this device, when the device is in the target optimum combustion state, the air-fuel ratio of the region where the sensor is arranged is near the transition range of the output of the sensor, and the mixture of the fuel and air passing through the burner section 51 is mixed. It is configured by differentiating the proportion in advance between the location corresponding to the placement of the sensor 53 and the other location, that is, different in advance in the space portion in which the sensor 53 is arranged in the combustion space 52 and the other space portion, and thus the originally optimum combustion state. The feature is that even if a sensor having no output transition region at the air-fuel ratio is used, combustion control can be performed with high sensitivity.

Further, in the above configuration, the gas distributed to the detection flame F ₁ is the addition of the weakly-energized secondary mixed gas from the second mixing adjustment chamber 57, and the total amount of gas is reduced. , The amount of heat received by the sensor 53 is also reduced, and the sensor 53
The durability of is increased.

<Effects> The present invention has the above-described configuration. According to the combustion device of the first aspect, the ceramic heater 14 is configured as an igniter by being loaded with a voltage from the power source through the ignition switch 17. By connecting a resistance detector 18 to the OFF contact 17b side of the ignition switch 17, the ceramic heater 14
Of the ignition switch 17 by forming a resistance detection circuit of the above and inputting a flame detection signal from the flame detector 15.
switch to the b side and thereby the resistance detector 18
Since the control unit 19 for controlling the combustion state of the burner unit 11 is provided by the electric resistance value of the ceramic heater 14 input from the above, the ceramic heater 14 can be used as an igniter at the start of operation, and ignition is performed. Then, the ceramic heater 14 can be automatically and easily switched to the combustion state detection sensor via the control unit 19 by the flame detection signal from the flame detector 15, whereby combustion in the burner unit 11 during combustion can be performed. The control of the state can be controlled by the control unit 19 based on the electric resistance value from the ceramic heater 14. That is, the ceramic heater 14 can also be used as the ignition means for combustion and the combustion state detection means for combustion control during combustion. Therefore, of course, it is not necessary to separately provide a sensor for detecting the combustion state during combustion.

According to the combustion device of the second aspect, the burner section is
51 is passed in advance so that the air-fuel ratio in the region where the sensor 53 is arranged is near the transition region of the output of the sensor 53 when the air-fuel ratio of the entire combustion in the combustion space 52 becomes the optimum air-fuel ratio of combustion. Since the mixing ratio of the fuel and air to be set is different between the location corresponding to the placement of the sensor 53 and the other location,
The change in the air-fuel ratio when the combustion is in the vicinity of the optimum air-fuel ratio can be accurately and quickly detected by the sensor 53 in the most sensitive detection area. Therefore, control by the control unit 59 accompanying non-detection of air-fuel can be performed accurately and quickly, and the transition range of the sensor 53 that detects the air-fuel ratio does not have to match the optimum air-fuel ratio of combustion, so the types of sensor 53 are limited. Even if the sensor has a slow output change at the optimum air-fuel ratio for combustion, it can be used sufficiently effectively. That is, a sensor having various characteristics or an inexpensive sensor can be used for combustion control.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of the device of the present invention,
FIG. 2 is a characteristic diagram of the ceramic heater, FIG. 3 is an overall configuration diagram showing a second embodiment of the device of the present invention, and FIG. 4 is a characteristic diagram of the sensor. 10: Combustion can body, 11: Burner part 12: Blower fan, 13: Fuel supply pipe 14: Ceramic heater, 17: Ignition switch 18: Resistance detector, 19: Control part F: Flame, 50: Combustion can body 51: Burner part, 52: Combustion space 53: Oxygen sensor, 55: Blower fan 56: First mixing adjusting chamber, 57: Second mixing adjusting chamber 59: Control part, F ₁ : Detection flame F ₂ : Main flame, F ₃ : Fire flame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Utsumi 32 Akashi-cho, Chuo-ku, Kobe, Hyogo Prefecture Noritsu Inc. (56) References JP 54-146029 (JP, A) JP 60- 194231 (JP, A)

Claims (2)

[Claims] 1. A burner section 11 and a burner section 11 in a combustion can body 10.
A combustion device having a ceramic heater 14 and a flame detector 15 in the vicinity of, and mixing the air from the blower fan 12 and the fuel from the fuel supply pipe 13 to burn them on the burner section 11. The ceramic heater 14 is configured as an igniter when a voltage is applied from a power source through an ignition switch 17, and a resistance detector 18 is connected to an off contact 17b side of the ignition switch 17 to thereby form the ceramic heater. 14
Of the ceramic heater 14 which inputs the flame detection signal from the flame detector 15 to switch the ignition switch 17 to the off contact 17b side and thereby input from the resistance detector 18. A combustion device, comprising a control unit 19 for controlling the combustion state of the burner unit 11 according to the electric resistance value of. 2. A combustion can body 50 has a burner portion 51 and a combustion space 52 above it, and a sensor 53 for detecting an air-fuel ratio of combustion is provided in a region of the combustion space 52. Is a combustion apparatus having a control unit 59 for controlling combustion by the air-fuel ratio detected by, the burner unit 51, when the air-fuel ratio of the entire combustion in the combustion space 52 is the optimum air-fuel ratio of combustion. In order that the air-fuel ratio in the area where the sensor 53 is arranged is near the transition area of the output of the sensor 53, the mixing ratio of the fuel and the air that passes in advance is determined by the position corresponding to the position of the sensor 53 and other places. Combustion device characterized by being different.