JP2989104B2 - Combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control apparatus used for diagnosing deterioration of ignition characteristics of a burner from ignition delay time of the burner in a combustion apparatus.

[0002]

2. Description of the Related Art Conventionally, a pre-purge has been performed following a start-up operation of a combustion device, and a response waiting time from a time when an ignition operation to a pilot burner is started until a flame is detected by a flame detector is measured. A monitoring device for a combustion device that determines that the combustion device is abnormal when the response waiting time at this time exceeds a preset limit time set value is disclosed in, for example, Japanese Utility Model Publication No. 5-12615.

[0003]

The conventional monitoring device for a combustion device is constructed as described above. Therefore, when the ignition delay time exceeds a predetermined value, the ignition current to the spark rod, the main burner and the pilot Although the burner shutoff control can be performed, the ignition characteristics of the main burner and the pilot burner cannot be grasped. Therefore, the tendency of the deterioration of the main burner and the pilot burner in use and the estimation of the burner replacement timing due to this are estimated. There were problems such as not being able to do.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. The deterioration tendency of each of these burners can be grasped from the number of startups of the main burner and the pilot burner for each ignition delay time. Accordingly, it is an object of the present invention to provide a combustion control device which enables maintenance and management of each burner before lockout, thereby realizing safe and continuous operation of the combustion device.

[0005]

A combustion control device according to the present invention includes an ignition transformer for supplying an ignition current to a spark rod facing a pilot burner of a combustion device, and an ignition of a main burner subsequent to the ignition of the pilot burner. A flame detector for detecting a flame is provided, and the microprocessor is provided with a flame detector for every ignition delay time from the start operation of ignition of the pilot burner based on the ignition current to the flame detection by the flame detector. The ignition characteristic of the burner is diagnosed based on the number of times of starting the ignition.

[0006]

The combustion control device according to the present invention accumulates the number of times of ignition of the pilot burner for each ignition delay time,
From the magnitude of the accumulated value, it is possible to select a burner having good ignition characteristics and determine the tendency of deterioration of the burner, and, if necessary, use the optimal burner characteristics obtained based on a predetermined number of sequence operations as learning data. Thereafter, the abnormality of the burner can be determined by comparing with the burner characteristics obtained by the same method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One 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 according to the present invention. In the drawing, reference numeral 1 denotes a power supply voltage detecting unit for detecting a power supply voltage for burner failure diagnosis, and 2 denotes a flame detector drive for driving a flame detector (not shown). Circuit.

Reference numeral 3 denotes a frame current detection unit for detecting a frame current based on the output of a flame detector described later.
Is an analog / digital converter that converts each detection output of the frame current detection unit 3 and the power supply voltage detection unit 1 into a digital signal.
It is a digital conversion unit.

Reference numeral 5 denotes a combustion control unit which receives the ignition / fire signal converted by the flame current detection unit 3,
A control signal for each combustion sequence is output to the relay output unit 6. The relay output unit 6 outputs a relay control signal for turning on and off a combustion control load 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 1 for detecting a primary current of an ignition transformer, which will be described later, based on an output from a relay output unit 6.
In the secondary current detector, the detection output is also input to the analog / digital converter 4 and is converted into a digital signal. In the present invention, the primary current detection timing by the primary current detection unit 7 is the ignition start operation timing of the pilot burner. Reference numeral 8 denotes a signal input unit for inputting a feedback signal from the relay output unit 6 to a microprocessor described later.

Reference numeral 9 denotes a microprocessor, which is based on the flame current from the flame current detection unit, and measures the average and deviation data of the flame current for each combustion sequence and the flame data in the burner optimum state. The average value of the current and the learning data, which is the deviation value, are compared with each other, and the diagnosis of the burner failure or the prediction of the burner failure is performed based on the deviation of each data.

Further, the microprocessor 9 determines the ignition of the burner from the number of times the pilot burner is activated for each ignition delay time from the operation of starting the ignition of the pilot burner to the ignition of the main burner by the flame detector. Diagnose the characteristics.

If necessary, the optimum burner characteristics obtained based on a predetermined number of sequence operations are used as learning data, and thereafter, the burner characteristics can be compared with the burner characteristics obtained by the same method to diagnose a burner abnormality. .

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

Reference numeral 10 denotes a memory for storing data input to the microprocessor 9 and the learning data, etc., 11 a display unit for displaying a processing result and a diagnosis result of the data, and 12 a display unit for displaying a processing result and a diagnosis result of the data. This is a communication interface unit for outputting to the outside.

FIG. 2 shows a combustion apparatus according to the present invention. In FIG. 2, reference numeral 21 denotes a fan for blowing air, and reference numeral 22 denotes an air supply passage 21a.
This is a damper for adjusting the amount of air supplied to the main burner 25 by the fan 21 through the fan.

Reference numeral 23 denotes a damper motor for controlling the opening and closing of the damper 22; 24, two main valves (combustion valves) for adjusting the flow rate of gas supplied to the main burner 25 through a gas passage 26; There are two pilot valves (fuel valves) for adjusting the flow rate of the gas supplied to the pilot burner 29.

Further, reference numeral 30 denotes the above-mentioned spark rod arranged near the pilot burner 29, 31 denotes the above-mentioned ignition transformer for supplying an ignition current to the spark rod 30;
Reference numeral 32 denotes the above-described flame detector which is disposed near the main burner 25 and detects a flame.

Next, the operation will be described. The entire control flow of the combustion control device of the present invention is as shown in the control sequence diagram of FIG. 3, and includes an absorption type operation, a start signal, a wind pressure switch on a damper side, an input side such as a high limit and a low limit, and a damper operation. , Dumper High, Damper Low, Blower Motor, Ignition Transformer, Pilot Valve, Main Valve, Alarm, Alarm Standby, Main Valve Standby, etc. For each output side and display operation, prepurge, ignition wait, ignition trial, pilot only, main trial , Main stabilization, steady combustion, post-purge, etc., start timing and end timing are given.
The following combustion control is executed.

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

On the other hand, the flame detector 32 is driven by the flame detector drive circuit 2, and based on the detection signal output from the flame detector 32, the frame current detector 3 detects the frame current, and this detection output is also output. The signal is converted into a digital signal by the analog / digital converter 4 and input to the microprocessor 9. The detection timing of the frame current can be used as a reference for counting the ignition delay time of the present invention.

The flame current detector 3 converts and outputs an ignition / fire 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, the control output is input to the relay output section 6, and each relay operates to control the load for fuel control on and off.

The primary current detecting section 7 of the ignition transformer detects the primary current of the ignition transformer 31 from the output of the relay output section 6, and this detection output is also sent to the microprocessor 9 via the analog / digital conversion section 4. It is captured. This primary current can be used as a timing for the ignition start operation of the pilot burner 29 and as a reference for counting the ignition delay time.

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.

For this reason, the microprocessor 9 performs data processing of burner failure data and diagnosis of burner failure by using the power supply voltage, the frame current, and the feedback signal as inputs, and stores the result in the memory 10 or the like. It can be displayed on the display unit 11 or externally output through the communication interface unit 12.

On the other hand, the ignition transformer 31 supplies an ignition current to a spark rod 30 facing the pilot burner 29 of the combustion device, and the flame detector 32 detects a flame due to the ignition of the main burner 25 following the ignition of the pilot burner 29. doing.

Then, the microprocessor 9 counts the number of times the pilot burner 29 is activated for each ignition delay time from the ignition start operation of the pilot burner 29 based on the ignition current to the flame detection by the flame detector 32. By doing so, the ignition characteristics of the burner are diagnosed.

FIG. 4 shows an ignition characteristic diagram of such a burner.
For example, for each of the ignition delay times on the horizontal axis, the value obtained by accumulating the number of times the burner is started is plotted on the vertical axis.

According to this, the envelope A connecting the cumulative value of the number of activations of the burner suitable for use is located to the left with respect to the envelope B of the number of activations of another burner not suitable for use. A burner having characteristics can be selected and used as a burner having good ignition characteristics.

FIG. 5 is a graph showing the ignition characteristics according to the degree of deterioration of the same burner. For each of the ignition delay times shown on the horizontal axis, the values obtained by accumulating the number of times the burners are started are plotted on the vertical axis. ing.

According to this, for example, with respect to an envelope C connecting the cumulative value of the number of times of starting of the burner obtained at the beginning of use,
The envelope of the number of times of activation of the burner obtained after the lapse of a predetermined period after use is represented by D, and it is possible to detect or foresee abnormality or deterioration of the burner from a change in the envelope D with respect to these envelopes C. it can.

FIG. 6 is a flowchart showing a procedure for diagnosing the ignition characteristics of the burner by the microprocessor 9. According to this, first, learning is started (step ST
1), the number n of burner activations is n = 0, and the total number K ₁ , K ₂ , K ₃ , K ₄ , K ₅ for each ignition delay time is K
_1, K _2, K _3, is set to K _4, K ₅ = 0 (step ST2).

Subsequently, the burner is started (step ST).
3) The burner activation count is counted up (step ST4). Further, the ignition delay time t is counted, and it is first checked whether or not the ignition delay time t is before 1 second (step ST5).
Adds 1 to the cumulative number K ₁ at this time is set as K ₁ = K ₁ +1 (step ST6).

Subsequently, the ignition delay time t is 1 <t ≦
Every time 2,2 <t ≦ 3,3 <t ≦ 4, the cumulative number K _{2
= K 2 + 1, K 3} = K 3 + 1, K 4 = K 4 + 1, K 5 =
Continue to cumulative calculated as K ₅ +1 (step ST7~
Step ST13), K ₅ = when a K ₅ +1 (step ST13), and determines whether the burner start count n has reached the set number of times of learning (step ST14), steps ST3 is below its set learning frequency The following processing is re-executed, and when the set number of times of learning is exceeded, the learning is terminated (step ST15).

Further, the cumulative value of the number of times the burner is activated for each ignition delay time is accumulated for all the ignition delay time zones, and the ignition characteristic deterioration can be diagnosed by comparing these learned values with the actually measured values. .

That is, according to the procedure of steps ST1 to ST15, burner characteristics as shown in FIGS. 4 and 5 can be obtained. In this procedure, the burner activation count data of the same number as the learning count is obtained and compared with the learning result, thereby making it possible to judge or predict the abnormality of the burner.

[0037]

As described above, according to the present invention, an ignition transformer for supplying an ignition current to a spark rod facing a pilot burner of a combustion device, and a flame caused by ignition of a main burner subsequent to the ignition of the pilot burner are formed. A flame detector for detecting the ignition characteristics of the burner based on the number of times of activation of the pilot burner for each ignition delay time from the ignition operation of the pilot burner to the flame detection. With this configuration, the deterioration tendency of each of these burners can be grasped from the number of startups for each ignition delay time of the main burner and pilot burner, and maintenance and management of each burner can be performed before lockout. Thus, there can be obtained an effect that a safe and continuous operation of the combustion device can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a burner ignition characteristic diagnostic device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a combustion device according to the present invention.

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

FIG. 4 is a burner characteristic diagram showing an example of a diagnosis result of a burner ignition characteristic according to the present invention.

FIG. 5 is a burner characteristic diagram showing another example of the diagnosis result of the burner ignition characteristic according to the present invention.

FIG. 6 is a flowchart showing a procedure for diagnosing the ignition characteristics of a burner according to the present invention.

[Explanation of symbols]

 9 Microprocessor 25 Main burner 29 Pilot burner 30 Spark rod 31 Ignition transformer 32 Flame detector

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tetsuya Yamada 1-12-2 Kawana, Fujisawa-shi, Kanagawa Yamatake Honeywell Co., Ltd. Fujisawa Plant (56) References JP-A-7-1119965 (JP, A) 63-150706 (JP, A) J.H. 5-12615 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F23N 5/24 106 F23N 5/08

Claims (1)

(57) [Claims] An ignition transformer for supplying an ignition current to a spark rod facing a pilot burner of a combustion device;
A flame detector that detects a flame due to ignition of the main burner following the ignition of the pilot burner, and a number of times of starting the ignition of the pilot burner for each ignition delay time from the start operation of the ignition of the pilot burner to the flame detection. And a microprocessor for diagnosing the ignition characteristics of the burner.