JPH08145341A - Combustion control device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to correctly carry out abnormality determination and abnormality prediction of an ultraviolet ray detector according to a predetermined standard from the number of discharges and the discharge time obtained based on the output of the ultraviolet ray detector. An ultraviolet detector 32 for detecting ultraviolet rays by using a discharge phenomenon is provided, and the above-mentioned discharge phenomenon is detected by the microprocessor 9 based on the detection output of the ultraviolet detector 32 within a predetermined time after the ultraviolet rays are blocked. The number of discharges and the discharge time are measured, and the abnormality of the ultraviolet ray detector 32 is diagnosed based on the measurement result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device used for diagnosing ignition of a pilot burner of a combustion device and ignition of a main burner.

[0002]

2. Description of the Related Art Generally, a conventional combustion device used in a boiler or the like performs a pre-purge of fuel gas following its starting operation, and subsequently ignites the gas of a pilot burner by sparks from a spark rod, Then, the gas of the main burner is ignited to start the operation of this combustion device.

Further, in the above combustion apparatus, the ignition of the pilot burner and the ignition of the main burner are constantly monitored by a flame detector as an ultraviolet ray detector, and combustion is performed in accordance with a predetermined combustion sequence using this monitoring data. Control is running.

Therefore, such an ultraviolet detector must always function normally in order to operate the combustion device safely and reliably.
Management becomes extremely important.

As is well known, such an ultraviolet detector has, for example, a pair of discharge electrodes arranged in an ultraviolet-transparent gas-filled tube, and an alternating voltage is applied to these discharge electrodes so that an external voltage is applied from the outside. By receiving the ultraviolet rays, the gas in the tube is activated, a discharge phenomenon is generated according to the activated state, and an initial ultraviolet ray detection signal is taken out.

Therefore, for the above-mentioned maintenance and management, such a conventional ultraviolet detector is diagnosed as abnormal when the above-mentioned discharge phenomenon occurs in a state where there is no flame before the ignition sequence, and the discharge time is constant. If it continues for more than a time, it is diagnosed as abnormal.

In some cases, a shutter for blocking ultraviolet rays is provided in front of the ultraviolet ray detector to block unnecessary ultraviolet rays that should not be monitored, and the same diagnosis as described above may be performed.

[0008]

However, in such a conventional method for diagnosing an ultraviolet ray detector, when a discharge phenomenon is measured and it is immediately determined that an abnormality has occurred, an accidental or sporadic discharge phenomenon is immediately abnormalized. There was a problem that it was erroneously diagnosed as an occurrence.

Further, when the abnormality is diagnosed when the discharge phenomenon continues for a certain time or longer, there is a problem that the same diagnosis may be made even when the short discharge phenomenon occurs repeatedly. It was

The present invention has been made to solve the above-mentioned conventional problems, and the abnormality of the ultraviolet ray detector is determined according to a predetermined standard from the number of discharges and the discharge time obtained based on the output of the ultraviolet ray detector. It is an object of the present invention to obtain a combustion control device that can correctly realize judgment and failure prediction.

[0011]

A combustion control device according to the present invention is provided with an ultraviolet ray detector for detecting ultraviolet rays in a combustion chamber by utilizing a discharge phenomenon, and after the ultraviolet ray of the ultraviolet ray detector is cut off in a microprocessor. The number of discharges and the discharge time due to the above-mentioned discharge phenomenon are measured based on the detection output within a certain time, and the abnormality of the ultraviolet ray detector is diagnosed based on the measurement result.

[0012]

The combustion control device according to the present invention measures the number of discharges and the discharge time of the discharge phenomenon in the ultraviolet detector from the output of the ultraviolet detector within a certain time after the ultraviolet light is cut off, and these The abnormality of the ultraviolet ray detector is diagnosed from the measured value, and the content of the abnormality can be determined, for example, according to a map of the diagnostic content learned in advance.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a combustion control device of the present invention. In FIG. 1, 1 is a power supply voltage detection unit for detecting a power supply voltage for a burner failure diagnosis device, and 2 is a flame detector for driving a flame detector (not shown). It is a drive circuit.

Further, 3 is a frame current detecting section for detecting a frame current based on the output of a flame detector as an ultraviolet ray detector which will be described later, and 4 is each of the frame current detecting section 3 and the power supply voltage detecting section 1 and the like. An analog / digital converter that converts the detection output into a digital signal.

Further, 5 is a combustion controller, which receives an ignition / extinction signal converted by the flame current detector 3,
A control signal for each combustion sequence is output to the relay output unit 6. The relay output section 6 controls on / off of combustion control loads such as a fan blower, an ignition transformer, a pilot valve, a main valve, and a damper motor by each relay.

Reference numeral 7 denotes an ignition transformer primary current detection unit for detecting a primary current of an ignition transformer described later by the output from the relay output unit 6. This detection output is also input to the analog / digital conversion unit 4 and converted into a digital signal. To be done. Reference numeral 8 is a signal input unit for inputting the feedback signal from the relay output unit 6 to a microprocessor described later.

Further, 9 is a microprocessor, which measures the average value and deviation value of each flame current for each combustion sequence from the flame current detector 3 and the average value of each flame current in the optimum burner state. And a learning value which is a deviation value are compared with each other, and a burner failure or burner failure prediction is diagnosed from the deviation of each of these data.

In particular, in the present invention, the microprocessor 9 determines the number of discharges and the discharge time due to the discharge phenomenon of the flame detector based on the detection output within a fixed time after the ultraviolet input of the flame detector, which is an ultraviolet detector, is cut off. Measure
According to the measurement result, abnormality diagnosis of the flame detector is executed.

Therefore, the microprocessor 9 has a function as if it had therein a discharge detecting means, a discharge number measuring means and a discharge time measuring means.

Further, the microprocessor 9 has a function of receiving the feedback signal from the relay for controlling the combustion sequence and determining the cause of misfire or the cause of combustion failure.

Reference numeral 10 is a memory for storing the data input to the microprocessor 9 and the learning data, 11 is a display unit for displaying the processing result of the data, diagnostic result, etc., and 12 is the processing result of the data and diagnostic result. It is a communication interface unit that outputs to the outside.

FIG. 2 shows a combustion apparatus to be diagnosed by the burner failure diagnosis apparatus of the present invention. In FIG. 2, 21 is a fan for blowing air and 22 is a fan 2 through an air supply passage 21a.
1 is a damper that adjusts the amount of air blown to the main burner 25.

Further, 23 is a damper motor for controlling the opening and closing of the damper 22, 24 is two main valves (combustion valves) for adjusting the flow rate of the gas supplied to the main burner 25 through the gas passage 26, and 27 is through the gas passage 28. These are two pilot valves (fuel valves) that adjust the flow rate of gas supplied to the pilot burner 29.

Further, 30 is a spark rod arranged in the vicinity of the pilot burner 29, 31 is an ignition transformer for supplying an ignition current to the spark rod 30, 32 is arranged in the vicinity of the main burner 25, and ultraviolet ray detection for detecting a flame is performed. It is a flame detector as a vessel.

As described above, when the flame detector 32 receives ultraviolet rays from the outside, for example, the main burner 25, the gas in the tube is activated, and a discharge phenomenon occurs according to the degree of activation, and the initial ultraviolet ray detection is performed. Output a signal.

Next, the operation will be described. The overall control flow of the combustion control device of the present invention is as shown in the control sequence diagram of FIG. 3, and the absorption operation, the start signal, the wind pressure switch on the damper side, the input side such as the high limit and the low limit, and the damper operation. , Damper high, damper low, blower motor, ignition transformer, pilot valve, main valve, alarm, alarm standby and main valve standby output side, display operation, pre-purge, ignition wait, ignition trial, pilot only, main trial , Start timing and end timing of main stable, steady combustion, post purge, etc. are given, and in each of these control flows, in the present invention,
The following combustion control is executed.

That is, the power supply voltage detection unit 1 detects the voltage of the power supply, and the detected output is converted into a digital signal by the analog / digital conversion unit 4 and input to the microprocessor 9. The microprocessor 9 corrects the frame current based on this digital signal.

On the other hand, the flame detector 32 is driven by the flame detector driving circuit 2, and based on the detection signal output from the flame detector 32, the flame current detector 3 detects the flame current, and this detection output is also It is converted into a digital signal by the analog / digital converter 4 and input to the microprocessor 9.

The flame current detecting section 3 also converts and outputs an ignition / extinction signal based on the flame detection signal,
This is input to the fuel control unit 5. This fuel control unit 5
Then, the fuel sequence is controlled, and the control output thereof is input to the relay output section 6, and each relay operates to control the on / off control of the fuel control load.

On the other hand, the feedback signal from the relay output section 6 is input to the microprocessor 9 through the signal input section 8.

Therefore, the microprocessor 9 receives the power supply voltage, the frame current, and the feedback signal as inputs, executes data processing such as burner failure data and various kinds of failure diagnosis, and stores the results in the memory 10. , And can be output to the outside through the communication interface unit 12.

On the other hand, the microprocessor 9 shown in FIG.
As shown in (a), the spark check timing T ₁
The flame current in the flame detector 32 is monitored, and the discharge time T of the flame detector 32 after the input of ultraviolet rays is cut off.
A certain period including ₃ is set as the ultraviolet ray detection timing T ₂ ,
The decrease in the frame current during this period is monitored.

Further, in FIG. 4A, _iffCH- 1,
I _fCH -2 is a preset flame presence / absence determination level, and a frame signal exceeding this flame presence / absence determination level is shown in FIG.
As shown in (b), the discharge time and the number of discharges (the number of discharges) are counted to determine the abnormality of the ultraviolet detector. In this case, the presence / absence determination level I _fCH -1 is set to be large in the region A where the frame current is large, and the presence / absence determination level If _fCH -2 is set to be small in the region B where the frame current is small to improve the detection accuracy of the number of discharges. In the illustrated example, the presence / absence determination levels _IffCH- 1 and _IffCH- 2 have two levels, but three levels or more may be used. Further, the presence / absence determination level may continuously change.

Therefore, the microprocessor 9 realizes the diagnosis of the ultraviolet detector according to the procedure shown in FIG. 5 according to the discharge time and the count result of the number of discharges at the ultraviolet detection timing T ₂ .

As shown in the flow chart of FIG. 5, first, the time of shutting off the ultraviolet ray is set as the ultraviolet ray detection timing (step ST1), and the count values of the discharge time t and the discharge number C are set to 0 (step ST).
2).

Next, the flame detector 32, which is an ultraviolet detector.
On the basis of the output of the above, it is checked whether or not there is a frame signal as shown in FIG. 4 (b) (step ST3), and when it is determined that there is no frame signal, the ultraviolet ray detection timing T ₂ further elapses. Check whether or not (step ST
4) When the time has elapsed, it is determined (determined) that the discharge time t and the number of discharges C do not exist (step ST5).

Then, according to this judgment result, a diagnosis based on the diagnosis table, that is, the flame detector 32 in this case is judged to be normal (step ST).
6).

On the other hand, if it is determined in step ST3 that there is a frame signal, the discharge time t is measured from the frame signal (step ST7), and it is further determined whether or not there is a frame signal (step ST8). ), In some cases, the frame time t is measured in step ST7.

On the other hand, if it is determined that there is no frame signal, then 1 is added to the number of discharges C (step ST9), and from step ST3 to step ST9 until the ultraviolet ray detection timing T ₂ elapses. The process of is repeated.

Then, after the passage of the ultraviolet ray detection timing T _{2, the} processes of steps ST5 and ST6 are executed, and the diagnosis according to the discharge time t and the number of discharges C is carried out.

FIG. 6 shows the above diagnosis table, in which whether the abnormality of the flame detector 32 is mild or severe is set according to the length of the discharge time t and the number of discharges C based on the learning result. There is. For example, in the area X centered on the boundary line L, it is instructed to immediately lock out the combustion control, and in the area Y, an alarm is issued as a slight abnormality, and the pre-purge is instructed.

FIG. 7 shows a failure content judgment processing procedure of the flame detector 32 executed by the microprocessor 9 based on the above diagnosis result.

Here, first, the count value K of the recycle counter is set to K = 0 (step ST11),
Subsequently, the diagnostic process shown in FIG. 4 is executed (step ST1
2) Based on this diagnosis result, it is determined whether or not the flame detector 32 is abnormal (step ST13).

If it is determined to be abnormal, it is then checked whether or not the count value K has exceeded the set number of recycles (step ST14), and if it exceeds the set number of times, an alarm is issued, Lockout such as burner combustion control is performed (step ST15).

On the other hand, if the set number of times has not been exceeded, 1 is added to the count value K of the recycle counter (step ST16), the pre-purge is restored, and the combustion control is restarted (step ST17). Then, the processing from step ST12 onward is executed. Note that the above step S
When it is determined that the diagnosis result is not abnormal at T13, the process proceeds to the next sequence.

As described above, the abnormality of the flame detector 32 can be grasped by referring to the diagnostic map according to the discharge time and the number of times of discharge, and the discharge is erroneous due to a single or accidental discharge or a repetition of short discharge. It is possible to reliably avoid the abnormality determination.

In general, the flame detector 32, which is an ultraviolet ray detector, sometimes catches cosmic rays and the like as an accidental pseudo flame. Conventionally, at this time, combustion control was locked out immediately or after a certain period of time. By the abnormality determination method based on the measurement of the number of discharges and the discharge time as described above, the lockout caused by the pseudo flame can be avoided and the combustion control can be stably and continuously realized.

[0048]

As described above, according to the present invention, the ultraviolet ray detector for detecting the ultraviolet ray by utilizing the discharge phenomenon is provided, and the microprocessor is provided with a predetermined time after the ultraviolet ray of the ultraviolet ray detector is cut off. It is configured to measure the number of discharges and the discharge time due to the above-mentioned discharge phenomenon based on the detection output of the above, and further to diagnose the abnormality of the ultraviolet detector based on the measurement result. And, there is an effect that the one that can correctly execute the abnormality forecast is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a combustion control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a combustion device according to the present invention, and is a conceptual diagram showing the combustion device as a burner failure diagnosis target.

FIG. 3 is a control sequence diagram showing a control procedure of the combustion control device of the present invention.

FIG. 4 is a timing chart of a frame signal according to the present invention.

FIG. 5 is a flowchart showing a diagnostic procedure by the combustion control device of the present invention.

FIG. 6 is an abnormality diagnosis map diagram used for abnormality diagnosis of the present invention.

FIG. 7 is a flowchart showing a sequence processing procedure based on a failure diagnosis result according to the present invention.

[Explanation of symbols]

 9 Microprocessor 32 Flame detector (UV detector)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hakuichi Kubota 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (72) Inventor Toshiya Arai 1-12 Kawana, Fujisawa, Kanagawa Prefecture No. 2 Yamatake Honeywell Co., Ltd. Fujisawa Factory

Claims (1)

[Claims] 1. The discharge phenomenon according to the above-mentioned discharge phenomenon, based on an ultraviolet ray detector for detecting ultraviolet rays in a flame in a combustion chamber by utilizing a discharge phenomenon, and a detection output within a predetermined time after the ultraviolet ray is cut off by the ultraviolet ray detector. A combustion control device comprising a microprocessor for measuring the number of discharges and the discharge time and diagnosing an abnormality of the ultraviolet detector based on the measurement result.