JP2000009316A - Burner flame monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assuredly decide that all flames are lost and rapidly stop the supply of fuel to each burner if the flameout of all burners should be generated even upon turning on the dummy switch of a corresponding flame detector when the flame detector is adjusted at the time of a test operation. SOLUTION: A flame monitor circuit 6 recognizes not only the presence and absence of the individual flame of a corresponding burner 2 but also the presence and absence of flames of other burners 2 based on a detecting signal 5 from each flame detector 4. When other fames are not recognized even while a dummy switch recognizing the presece of an individual flame irrespective of the presence and absence of the individual flame is turned on relative to a desired flame detector, the flame monitor circuit decides that all flames are lost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner flame monitoring device.

[0002]

2. Description of the Related Art Generally, in a boiler or the like, a burner flame monitoring device is used to confirm the presence or absence of a burner flame in a furnace.

In the burner flame monitoring apparatus, as shown in FIG. 3, a flame detector 4 is provided in a furnace 3 in which a plurality of burners 2 of a boiler 1 are provided, corresponding to each burner 2. During operation of the boiler 1, the detection signal 5 from each of the flame detectors 4 is input to a flame monitoring circuit 6, and the flame monitoring circuit 6 determines whether or not there is a flame on the tip side of each burner 2. Has become.

The flame monitoring circuit 6 will be described in detail.
The flame monitoring circuit 6 recognizes the presence or absence of an individual flame (self-flame) by capturing the light brightness 7 and the high-frequency component 8a of the light flicker 8 based on the detection signal 5 from each of the flame detectors 4. An individual flame presence / absence signal 9 representing the presence / absence of the individual flame
Is input to the OR circuit 10, and a dummy switch signal 11 from a dummy switch indicating that there is an individual flame irrespective of the presence or absence of an individual flame is input to the OR circuit 10.
The OR signal 12 output from the R circuit 10 is input to the AND circuit 14 via the NOT circuit 13 and the burner valve 16 provided in the fuel supply line 15 to the corresponding burner 2 is opened. A burner valve open signal 17 of "1" is input to the AND circuit 14, and the AND circuit 14
It is determined whether there is a flame on the tip side of each burner 2 based on the logical product signal 18 output from the NOT circuit 1.
3 is input to the AND circuit 19, the AND signal 20 output from the AND circuit 19 is input to the AND circuit 21, and all the burner valves 16
Is input to the AND circuit 21 via the NOT circuit 23, and outputs the all burner valve closing signal 22 which becomes "1" when is closed.
A circuit is configured to determine whether or not all flames have been lost based on a logical product signal 24 output from the AND circuit 21.

The high-frequency component 8a of the light flicker 8
Are extracted by a band-pass filter (BPF) not shown.

During operation of the boiler 1, a detection signal 5 from each of the flame detectors 4 is input to a flame monitoring circuit 6, and the flame monitoring circuit 6 generates light based on the detection signal 5 from each of the flame detectors 4. The presence or absence of an individual flame (self-flame) is recognized by capturing the brightness 7 and the high-frequency component 8a of the flickering light 8.

If there is an individual flame, the individual flame presence / absence signal 9 indicating the presence / absence of the individual flame becomes "1" and the O
Since the OR signal 12 input to the R circuit 10 and output from the OR circuit 10 becomes “1” and the signal “0” is input to the AND circuit 14 via the NOT circuit 13, the corresponding burner Irrespective of whether the burner valve 16 provided in the middle of the fuel supply line 15 to the fuel supply line 2 is open or closed, that is, whether the burner valve open signal 17 is "1" or "0",
4 is "0", and it is determined that there is a flame in the corresponding burner 2 and there is no misfire, while the signal 13a of "0" output from the NOT circuit 13 gives The logical product signal 20 output from the AND circuit 19 becomes “0”, and regardless of whether the all burner valve closing signals 22 are “1” or “0”, A
The logical product signal 24 output from the ND circuit 21 becomes "0", and it is determined that at least one burner 2 has a flame and all flames have not been lost.

If the individual flame does not exist, the individual flame presence / absence signal 9 indicating the presence / absence of the individual flame becomes "0" and is inputted to the OR circuit 10, where the dummy switch is turned off and the dummy switch is turned off. When the signal 11 is also “0”, the OR
The OR signal 12 output from the circuit 10 becomes “0” and the signal of “1” is output via the NOT circuit 13 to the AND circuit 1.
When the burner valve 16 provided in the fuel supply line 15 to the corresponding burner 2 is opened and the burner valve open signal 17 is "1", the AND circuit 14
Is output as "1", and it is determined that the corresponding burner 2 is misfired and no flame is present. If all other burners 2 are misfired and there is no flame, All the signals 13a input to the AND circuit 19 become "1", the AND signal 20 output from the AND circuit 19 becomes "1", and all the burner valve closing signals 22 become "0", that is, all the burner valves. 16 is not closed, a signal of "1" is input to the AND circuit 21 via the NOT circuit 23, and the AND signal 24 output from the AND circuit 21 becomes "1", and the total flame Is determined to be lost.

When it is determined that all the flames have been lost, a command to close all the burner valves 16 is output immediately, the supply of fuel to each burner 2 is stopped, and an unexpected Is avoided.

[0010]

When the flame detector 4 is adjusted at the time of a test run or the like, the individual flame of the burner 2 is temporarily turned on by turning on a dummy switch of the corresponding flame detector 4. Even if all the burners 2 are misfired, it is necessary to adjust the gain or the like while outputting a signal indicating that there is an individual flame even if there is a misfire. Since the switch signal 11 is “1” and the signal 13 a output from the NOT circuit 13 is “0”, the AND signal 24 output from the AND circuit 21 is also “0”, and all flames are lost. Therefore, there is a possibility that the supply of fuel to each burner 2 may be continued without outputting a command to close all the burner valves 16.

According to the present invention, in consideration of such circumstances, when the flame detector is adjusted at the time of test operation or the like, even if the corresponding dummy switch of the flame detector is turned on, all the burners are misfired. In this case, it is an object of the present invention to provide a burner flame monitoring device which can reliably determine that all flames have been lost and can quickly take measures such as stopping supply of fuel to each burner.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a burner flame monitoring device in a furnace provided with a plurality of burners, wherein the flame detection device is provided for each burner and detects a flame of the burner. And the presence / absence of an individual flame of the corresponding burner and the presence / absence of another flame of another burner based on the detection signal from each of the flame detectors. A flame monitoring circuit which, even when the switch is turned on for a desired flame detector, determines that all flames have been lost if no other flame is recognized. It is related to the flame monitoring device.

In the burner flame monitoring device, the presence or absence of the individual flame of the corresponding burner is recognized based on the brightness of the light detected by the flame detector and the high frequency component of the flicker of the light, and the other flame of the other burner is recognized. Can be recognized based on the brightness of light and the low-frequency component of flickering light.

According to the above means, the following effects can be obtained.

When the dummy switch of the corresponding flame detector is turned on in order to adjust the flame detector at the time of a test run or the like, there is an individual flame regardless of the presence or absence of the individual flame. In, based on the detection signal from each flame detector, instead of simply recognizing the presence or absence of an individual flame of the corresponding burner, it is also made to recognize the presence or absence of other flames, so from each flame detector If no other flame is recognized based on the detection signal input to the flame monitoring circuit, it is definitely determined that all flames have been lost, and a command to close all burner valves is output immediately, and each burner is output. The supply of fuel to the furnace is stopped, and the occurrence of an accident in the furnace is avoided.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention. In the figure, portions denoted by the same reference numerals as those in FIG. 3 represent the same components. 1, but the feature of the illustrated example is that, as shown in FIG. 1, in a flame monitoring circuit 6, based on a detection signal 5 from each flame detector 4, an individual flame of a corresponding burner 2 is detected. Not only the presence / absence but also the presence / absence of another flame of the other burner 2 is recognized, and the dummy switch which has the individual flame regardless of the presence / absence of the individual flame is turned on for the desired flame detector 4 Even if there is any other flame, it is configured to determine that the entire flame has been lost if no other flame is recognized.

Here, it has been found that the magnitude of the flicker of the light with respect to the frequency of the individual flame and the frequency of the other flame shows a tendency as shown in FIG. High-frequency component 8a (about 100 [Hz]) of light brightness 7 and light flicker 8 based on detection signal 5 from
The presence / absence of an individual flame (self-flame) can be recognized by grasping the front and rear), while the detection signal 5 from each of the flame detectors 4 is provided when there is no individual flame of the corresponding burner 2.
Low frequency component 8 of light brightness 7 and light flicker 8 based on
By grasping b (approximately 2.5 to 10 [Hz]), the presence or absence of another flame of the other burner 2 can be recognized.

For this reason, as shown in FIG. 1, the low-frequency component 8b of the light flicker 8 is extracted by a band-pass filter (BPF) (not shown), and the light brightness 7 and the low-frequency "1" when there is a component 8b
The other flame presence / absence signal 25 and the individual flame presence / absence signal 9 are input to an OR circuit 26, and the OR signal output from the OR circuit 26 is used as an in-furnace flame presence / absence signal 27 as an OR circuit 28.
And the OR signal 2 output from the OR circuit 28
9 is input to the AND circuit 31 via the NOT circuit 30, and the all-burner valve closing signal 22 is input to the AND circuit 31 via the NOT circuit, and the AND signal 32 output from the AND circuit 31; The AND signal 24 output from the AND circuit 21 is input to the OR circuit 33, and it is determined whether or not all flames have been lost based on the OR signal 34 output from the OR circuit 33. The monitoring circuit 6 is configured.

Next, the operation of the illustrated example will be described.

When the dummy switch of the corresponding flame detector 4 is turned on in order to adjust the flame detector 4 at the time of a test run or the like, the dummy switch signal 11 becomes "1" and the O
Since the OR signal 12 input to the R circuit 10 and output from the OR circuit 10 becomes “1” and the signal “0” is input to the AND circuit 14 via the NOT circuit 13, the corresponding burner Irrespective of whether the burner valve 16 provided in the middle of the fuel supply line 15 to the fuel supply line 2 is open or closed, that is, whether the burner valve open signal 17 is "1" or "0",
4 is "0", and it is determined that there is a flame in the corresponding burner 2 and there is no misfire, while the signal 13a of "0" output from the NOT circuit 13 gives The logical product signal 20 output from the AND circuit 19 becomes “0”, and regardless of whether the all burner valve closing signals 22 are “1” or “0”, A
The logical product signal 24 output from the ND circuit 21 becomes “0” and is input to the OR circuit 33. In this case,
When all the burners 2 are misfired, the individual flame presence / absence signal 9 representing the presence / absence of the individual flame becomes “0” and the OR circuit 2
6, the other flame presence / absence signal 25 also becomes "0" and is inputted to the OR circuit 26, and the OR signal outputted from the OR circuit 26 is all "0".
7 is input to the OR circuit 28, and the logical sum signal 29 output from the OR circuit 28 becomes “0” and the NOT circuit 3
When the all-burner-valve-close signal 22 is input to the AND circuit 31 as a signal of “1” via “0” and the all-burner-valve-close signal 22 is not “0”, that is, not all the burner valves 16 are closed,
The signal of “1” is input to the AND circuit 31 via the circuit 23, and the AND signal 32 output from the AND circuit 31 becomes “1” and is input to the OR circuit 33.
The OR signal 34 output from the OR circuit 33 is "1"
And it is determined that all flames have been lost.

As a result, when the dummy switch signal 11 is "1" and the signal 13
Even if a is “0”, the flame monitoring circuit 6 does not simply recognize the individual flame of the corresponding burner 2 based on the detection signal 5 from each flame detector 4, When there is no other flame, other flames are recognized. Therefore, if no other flame is recognized based on the detection signal 5 input from each flame detector 4 to the flame monitoring circuit 6, it is surely determined that all flames have been lost. The command to close all the burner valves 16 is output immediately, the supply of fuel to each burner 2 is stopped, and the occurrence of an unexpected situation in the furnace 3 is avoided.

In this way, when the flame detector 4 is adjusted at the time of a test run or the like, even if the corresponding dummy switch of the flame detector 4 is turned on, if all the burners 2 are misfired, It can be reliably determined that the flame has been lost,
Measures such as stopping the supply of fuel to each burner 2 can be taken promptly.

It should be noted that the burner flame monitoring device of the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0025]

As described above, according to the burner flame monitoring apparatus of the present invention, when the flame detector is adjusted at the time of test operation or the like, even if the dummy switch of the corresponding flame detector is turned on. In the unlikely event that all burners are misfired, it is possible to reliably determine that all flames have been lost, and to quickly take measures such as stopping the supply of fuel to each burner. I can play.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a diagram showing the magnitude of flicker of light with respect to the frequency of an individual flame and another flame in an example of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional example.

[Explanation of symbols]

 2 Burner 3 Furnace 4 Flame detector 5 Detection signal 6 Flame monitoring circuit 7 Light brightness 8 Light flicker 8a High frequency component 8b Low frequency component 9 Individual flame presence / absence signal 11 Dummy switch signal 15 Fuel supply line 16 Burner valve 25 Other Flame presence / absence signal 27 Furnace presence / absence signal

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Sudo 3-2-16-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Toyosu Sogo Office (72) Inventor Shigehiro Miyamae 3-2-2 Toyosu, Koto-ku, Tokyo No. 16 Ishikawajima Harima Heavy Industries, Ltd. Toyosu General Office F-term (reference) 3K003 XA01 XA04 XB02 XC04 3K005 QA01 QB03 QC01 QC04 QC08

Claims (2)

[Claims] 1. A burner flame monitoring device in a furnace in which a plurality of burners are provided, wherein the flame detector is provided corresponding to each burner and detects a burner flame, and each of the flame detectors Recognizes the presence or absence of an individual flame of the corresponding burner and the presence or absence of another flame of another burner based on the detection signal from, and a dummy switch that has an individual flame regardless of the presence or absence of the individual flame is connected to the desired flame detector. A burner flame monitoring device comprising: a flame monitoring circuit that determines that all flames have been lost when no other flame is recognized at all, even when the flame is turned on. 2. The method according to claim 1, wherein the presence or absence of the individual flame of the corresponding burner is recognized based on the brightness of the light detected by the flame detector and the high-frequency component of the flicker of the light. The burner flame monitoring device according to claim 1, wherein the recognition is performed based on the low frequency component of the light flicker.