JP2003176913A - Method for determining abnormal combustion, and method for controlling combustion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically detect if abnormal combustion followed by impact exists or not to prevent breakage of a heat device itself, a flue, a stack, etc., and a fire or the like, due to abnormal combustion followed by impact. <P>SOLUTION: If abnormal combustion exists or not is determined based on a pressure in a ventilation passage when the heat device 1 is ignited. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a method for controlling combustion in a thermal appliance, such as a method for determining abnormal combustion accompanied by shock such as backfire.

[0002]

2. Description of the Related Art Abnormal combustion accompanied by impact may occur in a thermal device that combusts fuel and exchanges heat with the generated heat quantity, for example, water. The abnormal combustion accompanied by the shock is abnormal combustion caused by poor ventilation in the combustion chamber before ignition, defective ignition means for fuel, defective mixing state of combustion air and fuel, and the like. Further, the abnormal combustion accompanied by the shock is an explosive combustion unlike the normal combustion, and its impact force and impact noise are large. For example, the state in which the abnormal combustion is slight is a state in which ignition accompanied by impact occurs at the time of ignition and then the combustion continues. The state in which the abnormal combustion is severe is a state in which ignition accompanied by a large impact occurs at the time of ignition, and then the flame is extinguished. Then, the abnormal combustion accompanied by the impact often occurs irregularly. For this reason,
Even if abnormal combustion accompanied by a slight impact occurs repeatedly, it will cause damage to the thermal equipment itself or a flue that exhausts the combustion exhaust gas of this thermal equipment to the outside, a chimney, etc., and a fire, etc. . However, the conventional determination of the presence or absence of abnormal combustion is
It was necessary for the manager of the thermal equipment to directly monitor and judge. Further, after the damage of the thermal equipment itself, the flue, the chimney, etc. was discovered, it was determined that the cause was abnormal combustion accompanied by impact. Further, feedback to the combustion control based on the detection of the presence or absence of abnormal combustion has not been performed.

[0003]

The problem to be solved by the present invention is to automatically detect the presence / absence of abnormal combustion accompanied by impact, and to detect the thermal equipment itself, flue, It is to prevent damage such as chimneys and fire.

[0004]

The present invention has been made to solve the above problems, and the invention according to claim 1 is based on the pressure value in the ventilation passage when the thermal equipment is ignited. The feature is that the presence or absence of abnormal combustion is determined.

The invention according to claim 2 is characterized in that the pressure value of the ventilation passage at the time of ignition of the thermal equipment is detected, and when the detected pressure value is equal to or higher than a specified value, it is determined that abnormal combustion has occurred. I am trying.

The invention according to claim 3 is characterized in that the pressure value of the ventilation passage at the time of ignition of the thermal equipment is detected, and when the detected pressure value is a relative value or more, it is determined that abnormal combustion has occurred. I am trying.

According to a fourth aspect of the present invention, the presence or absence of abnormal combustion of the heat equipment is detected, and the combustion of the heat equipment is controlled based on the detection result.

Further, the invention according to claim 5 is characterized in that the presence or absence of the abnormal combustion is detected based on the pressure value of the ventilation passage of the thermal equipment.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described. The present invention is directed to a burner for burning fuel, a can body for exchanging heat generated by the burner with a heat medium, and a smoke. It can be suitably implemented in a thermal device having a passage and a chimney. In the thermal equipment, for example, abnormal combustion accompanied by shock such as backfire may occur.

First, an embodiment of a method for determining the presence or absence of abnormal combustion accompanied by impact according to the present invention will be described. A boiler will be described as an example of a thermal device to which the present invention is applied. The boiler is a blower that is an air supply unit for combustion, an air duct that is a ventilation passage connected to the blower, and a pressure that detects the pressure of the air supplied by the blower that is provided in the air duct. A sensor,
It is configured by a controller that controls these.

The pressure sensor detects the pressure value in the air duct at the time of ignition of the boiler. If the detected value is equal to or more than a specified value, it is determined that the abnormal combustion has occurred. That is, the degree of impact at the time of ignition is detected by the pressure value, and the presence or absence of the abnormal combustion is determined. Here, the specified value is set as a pressure value at which the degree of impact due to the abnormal combustion does not result in damage to the boiler, flue, chimney, and the like.

Here, it is preferable that the pressure sensor is arranged in the air duct, but depending on the implementation, a ventilation passage other than the air duct is also preferable. For example, as the ventilation passage, a portion capable of detecting the pressure inside the blower, a portion capable of detecting the pressure inside the wind box of the burner, a portion capable of detecting the pressure inside the combustion chamber of the boiler (so-called furnace), the can There are a part that can detect the pressure in the flow path through which the combustion gas in the body passes, a part that can detect the pressure in the flue and the stack.

Further, when the detected pressure value changes with time, for example, when the pressure value in the furnace or in the passage through which the combustion gas passes gradually increases with time,
It is also preferable to use a relative value instead of using the specified value, and to determine that the abnormal combustion has occurred if the relative value is a predetermined value or more. Here, the relative value is
For example, it is a value obtained by adding the specified value to the pressure value in the air duct at the start of measurement.

Next, an embodiment of the combustion control method according to the present invention will be described. A boiler will be described as an example of a thermal device to which the present invention is applied. This combustion control method detects the presence or absence of abnormal combustion accompanied by impact of the boiler, and controls the combustion of the boiler at the time of detection. That is, when the occurrence of the abnormal combustion of the boiler is detected, after the occurrence of the abnormal combustion is detected, in order to prevent the occurrence of the abnormal combustion accompanied by a shock again, for example, the combustion of the burner of the boiler is performed. The control is performed so as to stop or give an alarm.

Here, the presence or absence of the abnormal combustion is detected based on the pressure value of the ventilation passage of the boiler. The pressure value of the ventilation channel is detected by a pressure sensor provided in a portion where the pressure value can be detected. The parts include an air duct that supplies combustion air to the burner, a wind box of the burner, a blower, a combustion chamber of the boiler (so-called furnace), a passage through which combustion gas in the boiler can passes, and Either a flue or a chimney. Then, when the occurrence of the abnormal combustion of the boiler is detected, the combustion of the boiler is controlled at that time.

With this, the occurrence of the abnormal combustion is automatically detected without the supervision of the manager of the boiler, and the impact due to the repeated abnormal combustion is avoided, and the boiler, the flue, and the chimney are prevented. Prevent damage and fire.

[0017]

EXAMPLES Specific examples of the present invention will be described below. First, as a first embodiment, a case where the method is applied to a method for determining the presence or absence of abnormal combustion accompanied by impact of a boiler will be described in detail with reference to the drawings. FIG. 1 is a partially broken explanatory view of a boiler to which the method for determining abnormal combustion according to the present invention is applied.

In FIG. 1, the boiler is a hot water boiler 1 for heating water. This hot water boiler 1 has a can body 2 that holds water therein, a burner 3 that heats the water in the can body 2, and a blower 4 that supplies combustion air to the burner 3.
It is composed of and. Furthermore, the hot water boiler 1
Is equipped with a temperature sensor (not shown) for detecting the water temperature in the can body 2.

The can body 2 is provided with a water storage part 5 for storing water in the can body 2 and a combustion chamber (hereinafter referred to as "inside furnace 6") for forming a flame of the burner 3. There is. A chimney 7 for discharging the combustion exhaust gas from the furnace 6 to the outside is connected to the side surface of the can body 2.

The burner 3 is connected to the blower 4 via an air duct 8 and has a wind box 9 for rectifying the combustion air supplied from the air duct 8. The burner 3 includes a fuel control valve 11 provided in a fuel supply line 10, a nozzle 12 for spraying fuel, an ignition transformer 13 for generating a high voltage, and an ignition gate 14 for generating a spark at the high voltage. There is. The burner 3 includes an air register 15 and a flame holding plate 16 provided in the furnace 6 for rectifying the combustion air. Further, the burner 3 includes a flame sensor (not shown) that detects a flame.

The air duct 8 includes the air duct 8
A pressure sensor 17 for detecting the internal pressure is provided.
The pressure sensor 17 detects the pressure value in the air duct 8, converts it into an electric signal, and then outputs it to the controller 18.

The controller 18 is connected to the blower 4, the fuel control valve 11, the ignition transformer 13, the pressure sensor 17, the flame sensor and the temperature sensor by signal lines (reference numerals omitted).

Next, the first pattern of the method for determining the presence or absence of the abnormal combustion of the hot water boiler 1 having the above-mentioned configuration will be described.

In the operation of the hot water boiler 1, first, the blower 4 is operated in response to a combustion start command from the temperature sensor, and ventilation (pre-purge) of the furnace 6 is performed. Next, while the blower 4 continues to operate, fuel is sprayed from the nozzle 12 and the ignition transformer 1
3 is activated and the fuel is ignited.

At the time of this ignition, the presence or absence of the abnormal combustion is determined. This abnormal combustion occurs in the inside of the furnace 6 before ignition.
Ventilation failure, the ignition transformer 13 and the ignition insulator 11 are defective, the mixing state of combustion air and fuel is defective,
It is an explosive combustion caused by a defect in the air register 15 and the flame holding plate 16. When this abnormal combustion occurs, a sudden change in the pressure value, that is, an impact force occurs in the ventilation passage of the hot water boiler 1. The ventilation passages in which the impact force is generated include the inside of the blower 4, the inside of the air duct 8, the inside of the wind box 9, the inside of the air register 15, the inside of the furnace 6 and the inside of the chimney 7.

Therefore, the pressure sensor 17 detects the pressure value in the air duct 8 when the hot water boiler 1 is ignited. If the pressure value detected by the pressure sensor 17 is equal to or greater than the specified value, the controller 18 determines that the abnormal combustion has occurred. That is, the degree of impact at the time of ignition is detected by the pressure value, and the presence or absence of the abnormal combustion is determined.

Here, the specified value is set as a pressure value at which the degree of impact due to the abnormal combustion does not damage the hot water boiler 1, the chimney 7, etc., for example, 300 mmH ₂ O. If the pressure value detected by the pressure sensor 17 is less than the specified value, the controller 18 determines that the abnormal combustion has not occurred.

Next, the second pattern of the method for determining the presence or absence of the abnormal combustion of the hot water boiler 1 will be described. In this second pattern, soot may adhere to the inside of the furnace 6 with the lapse of time, and the inside of the furnace 6 and the air register 1
5, the wind box 9 and the air duct 8
This corresponds to when the pressure value in the inside gradually increases. In this case, instead of using the specified value, a relative value is used, and if the relative value is equal to or greater than a predetermined value, the controller 18 determines that the abnormal combustion has occurred. Here, the relative value is, for example, a value obtained by adding the specified value to the pressure value of the air duct 8 at the start of measurement. If the pressure value detected by the pressure sensor 17 is less than the relative value, the controller 18 determines that the abnormal combustion has not occurred.

Next, the combustion control method of the present invention will be described as a second embodiment. The second embodiment will be described by taking the hot water boiler 1 as an example with reference to FIG. 1 as a heat device to which the present invention is applied.

This combustion control method detects the presence or absence of abnormal combustion associated with impact of the hot water boiler 1, and controls the combustion of the hot water boiler 1 at the time of detection. That is, when the occurrence of the abnormal combustion of the hot water boiler 1 is detected, after the time when the occurrence of the abnormal combustion is detected, the combustion of the burner 3 is stopped in order to prevent the occurrence of the abnormal combustion accompanied by another impact. Control to stop.

When the abnormal combustion occurs, a sudden change in the pressure value, that is, an impact force is generated in almost all locations in the ventilation passage of the hot water boiler 1. The presence or absence of the abnormal combustion in the second embodiment is detected by the pressure sensor 17 provided in the air duct 8. Then, when the occurrence of the abnormal combustion of the hot water boiler 1 is detected, the combustion of the burner 3 is controlled to stop at that time. When the occurrence of the abnormal combustion of the hot water boiler 1 is not detected, the burner 3 is controlled to continue the combustion.

As described above, according to the first embodiment and the second embodiment, the occurrence of the abnormal combustion can be automatically detected without the supervision of the manager of the hot water boiler 1. . Furthermore, it is possible to avoid the impact caused by the abnormal combustion that is repeatedly generated, and prevent the hot water boiler 1, the chimney 7, etc. from being damaged and fire.

[0033]

According to the present invention, since the presence or absence of abnormal combustion accompanied by impact can be automatically detected, damage to the thermal equipment itself, flue, chimney, etc. due to abnormal combustion accompanied by impact and fire, etc. Can be prevented.

[Brief description of drawings]

FIG. 1 is a partially broken explanatory view of a hot water boiler to which a method for determining the presence or absence of abnormal combustion accompanied by impact of the present invention is applied.

[Explanation of symbols]

1 Hot water boiler (heat equipment) 8 air ducts

Claims (5)

[Claims] 1. A method for determining abnormal combustion, which comprises determining the presence or absence of abnormal combustion based on the pressure value in the ventilation passage at the time of ignition of the thermal equipment 1. 2. An abnormal combustion determination method characterized by detecting a pressure value of a ventilation passage at the time of ignition of the thermal equipment 1, and determining that abnormal combustion has occurred when the detected pressure value is a specified value or more. . 3. An abnormal combustion determination method characterized by detecting a pressure value of a ventilation flow path at the time of ignition of the thermal equipment 1, and determining that abnormal combustion has occurred when the detected pressure value is a relative value or more. . 4. A combustion control method, comprising: detecting the presence or absence of abnormal combustion of the thermal equipment 1, and controlling the combustion of the thermal equipment 1 based on the detection result. 5. The combustion control method according to claim 4, wherein the presence or absence of the abnormal combustion is detected based on the pressure value of the ventilation passage of the thermal device 1.