JP3062019B2 - 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 device used for diagnosing ignition of a pilot burner or ignition of a main burner of a combustion device.

[0002]

2. Description of the Related Art In general, a conventional combustion device used in a boiler or the like performs a pre-purge of fuel gas following a start-up operation thereof, and subsequently ignites a gas of a pilot burner by a spark from a spark rod. Subsequently, the main burner gas is ignited to start operating the combustion device.

In the above-mentioned 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. 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 a pair of discharge electrodes arranged in, for example, an ultraviolet-transmissive gas-filled tube, and applies an AC voltage to these discharge electrodes in advance, so that an external voltage is applied. By receiving the ultraviolet rays, the gas in the tube is activated, a discharge phenomenon corresponding to the activated state is generated, and an initial ultraviolet detection signal is extracted.

Therefore, such a conventional ultraviolet detector performs a diagnosis for an abnormality or a constant discharge time when the discharge phenomenon occurs in a state where no flame exists before the ignition sequence for the maintenance and management. An abnormality is diagnosed if it continues for more than an hour.

[0007] In some cases, a shutter similar to the above is provided in front of the ultraviolet ray detector to cut off unnecessary ultraviolet rays which should not be monitored.

[0008]

However, in such a conventional method of diagnosing an ultraviolet detector, if a discharge phenomenon is measured and it is immediately determined that an abnormality has occurred, an accidental or spontaneous discharge phenomenon can be detected immediately. There was a problem that the diagnosis was made incorrectly.

[0009] Further, in the case where an abnormality is diagnosed when the discharge phenomenon continues for a certain period of time or more, the same diagnosis may be performed even when a short discharge phenomenon repeatedly occurs. Was.

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

[0011]

SUMMARY OF THE INVENTION A combustion control apparatus according to the present invention is provided with an ultraviolet ray detector for detecting ultraviolet rays in a combustion chamber using a discharge phenomenon, and irradiates the microprocessor with ultraviolet rays. 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 after cutting off, 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 within a certain period of time after the ultraviolet irradiation is cut out of the outputs of the ultraviolet detector. The abnormality of the ultraviolet detector is diagnosed from the measured values of the above, and the contents of the abnormality can be determined, for example, according to a map of the contents of the diagnosis learned in advance.

[0013]

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 a burner failure diagnosis device, and 2 denotes a flame detector for driving a flame detector (not shown). It is a drive circuit.

Reference numeral 3 denotes a frame current detector for detecting a frame current based on the output of a flame detector as an ultraviolet detector described later, and 4 denotes each of the frame current detector 3 and the power supply voltage detector 1 and the like. An analog / digital converter for converting a detection output into a digital signal.

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 controls on / off of 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 primary current detecting section for detecting a primary current of an ignition transformer, which will be described later, based on an output from a relay output section 6. The detected output is also input to the analog / digital conversion section 4 and converted into a digital signal. Is done. Reference numeral 8 denotes a signal input unit for inputting a feedback signal from the relay output unit 6 to a microprocessor described later.

Numeral 9 denotes a microprocessor, which is composed of a frame current detector 3 which measures the average value and deviation value of each frame current for each combustion sequence and the average value of each frame current in the burner optimum state. Then, a diagnosis of a burner failure or a burner failure prediction is performed based on the deviation of each data by comparing the deviation data with learning data as a deviation value.

In particular, according to the present invention, the microprocessor 9 determines the number of times of discharge and the discharge time due to the discharge phenomenon of the flame detector based on the detection output within a certain time after the UV input of the flame detector as the ultraviolet detector is cut off. Measure,
According to the measurement result, the abnormality diagnosis of the flame detector is executed.

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

Further, the microprocessor 9 has a function of receiving a feedback signal from a relay for controlling the combustion sequence and determining a cause of misfiring or a 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 device to be diagnosed by the burner failure diagnostic device of the present invention. In FIG. 2, reference numeral 21 denotes a fan for blowing air, and 22 denotes a fan 2 through an air supply passage 21a.
1 is a damper for adjusting the amount of air supplied to the main burner 25.

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 a 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 a spark rod arranged near the pilot burner 29, 31 denotes an ignition transformer for supplying an ignition current to the spark rod 30, and 32 denotes an ultraviolet ray detector arranged near the main burner 25 to detect a flame. It is a flame detector as a detector.

As described above, when the flame detector 32 receives an ultraviolet ray from the outside, for example, the main burner 25, the gas in the tube is activated, and a discharge phenomenon corresponding to the degree of the activation is generated. Output a signal.

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 stable, steady combustion, post-purge, etc., start and end timings. In each of these control flows, the present invention provides:
The following combustion control is executed.

That is, the power supply voltage detector 1 detects the power supply voltage, 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 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 unit 6, and each relay is operated to control the load for fuel control on and off.

On the other hand, a 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 executes data processing such as burner failure data and various failure diagnoses 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. , And can be externally output through the communication interface unit 12.

On the other hand, the above-mentioned microprocessor 9
As shown in (a), the spark check timing T ₁
It monitors the flame current in further UV
After interrupting the irradiation, a predetermined period including the discharge time T ₃ of the flame detector 32 as an ultraviolet detection timing T _2, monitors the decrease in the flame current in this period.

Also, in FIG. 4A, I _fCH -1,
_Ifch- 2 is a preset flame presence / absence determination level, and the frame signal exceeding this presence / absence determination level is shown in FIG.
As shown in (b), the discharge time and the number (the number of discharges) are counted for the abnormality determination of the ultraviolet detector. In this case, the presence / absence determination level _Ifch- 1 is set large in the region A where the frame current is large, and the presence / absence determination level _Ifch- 2 is set small in the region B where the frame current is small, and the detection accuracy of the number of discharges is increased. Although the illustrated example has two levels of the presence / absence determination levels _Ifch- 1 and _Iff- 2, it may have three or more levels. Further, the presence / absence determination level may change continuously.

[0034] Therefore, the microprocessor 9 according to the count result of the discharge time and the number of times of discharge in the ultraviolet detection timing T _2, according to the procedure shown in FIG. 5, to achieve a diagnostic UV detector.

As shown in the flow chart of FIG. 5, first, when the ultraviolet rays are cut off, the above-mentioned ultraviolet ray detection timing is set (step ST1), and the count values of the discharge time t and the number of discharges C are set to 0 (step ST1).
2).

Next, a flame detector 32, which is an ultraviolet detector, is used.
Based on the output, and FIG. 4 (b) there is a frame signal as shown in whether the checked (step ST3), if it is determined that there is no frame signal further elapses UV detection timing T ₂ (Step ST
4) If it has elapsed, it is determined (confirmed) that the discharge time t and the number of discharges C do not exist (step ST5).

Then, in accordance with the result of this determination, a diagnosis based on the diagnosis table, that is, a diagnosis that the flame detector 32 is normal in this case is made (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.

[0039] Then, on the other hand, if it is determined that there is no frame signal, in turn, adds 1 to the number of discharges C (step ST9), until after UV detection timing T _2, from step ST3 to step ST9 Is repeated.

Then, after the elapse of the ultraviolet ray detection timing T ₂ , the processing of steps ST5 and ST6 is executed, and diagnosis according to the discharge time t and the number of discharges C is performed.

FIG. 6 shows the above-mentioned diagnosis table, in which whether the abnormality of the flame detector 32 is mild or severe is set based on the learning result in accordance with the length of the discharge time t and the number of discharges C. It is. For example, in the area X centering on the boundary line L, an instruction is given to immediately lock out the combustion control, and in the area Y, a warning is issued as a slight abnormality to indicate that the prepurge should be performed.

FIG. 7 shows a procedure for judging the details of the failure of the flame detector 32 executed by the microprocessor 9 based on the result of the diagnosis.

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

Here, if it is determined that there is an abnormality, it is then checked whether or not the count value K has exceeded the set number of recycles (step ST14). Lockout such as burner combustion control is performed (step ST15).

On the other hand, if the number of times does not exceed the set number, 1 is added to the count value K of the recycle counter (step ST16), and the process returns to the pre-purge and restarts the combustion control (step ST17). , And executes the processing of step ST12 and subsequent steps. Note that the above step S
In T13, when it is determined that the diagnosis result is not abnormal, the process proceeds to the next sequence.

As described above, the abnormality of the flame detector 32 can be grasped by referring to the diagnosis map in accordance with the discharge time and the number of discharges, and erroneous discharges caused by sporadic or accidental discharges or repeated short discharges can be obtained. Abnormality determination can be reliably avoided.

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

[0048]

As it is evident from the foregoing description, according to the present invention, provided with a UV detector for detection by utilizing a discharge phenomenon ultraviolet, microprocessor, ultraviolet to the ultraviolet detector
Since the number of discharges and the discharge time due to the discharge phenomenon are measured based on the detection output within a certain period of time after the irradiation is cut off , and further based on the measurement result, the abnormality of the ultraviolet detector is diagnosed. Thus, there is an effect that an abnormality detection and an abnormality forecast of the ultraviolet detector can be correctly performed according to a predetermined standard.

[Brief description of the 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 a combustion device to be subjected to burner failure diagnosis.

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 diagnosis procedure by the combustion control device of the present invention.

FIG. 6 is an abnormality diagnosis map used for the 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)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Hakuichi Kubota 2-5-5, Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor, Toshiya Arai 1-12-2 Kawana, Fujisawa-shi, Kanagawa No. Yamatake Honeywell Co., Ltd. Fujisawa Plant (56) References JP-A-5-280733 (JP, A) JP-A-1-305223 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) F23M 11/04 F23N 5/08 F23N 5/24 106

Claims (1)

(57) [Claims] 1. An ultraviolet detector for detecting ultraviolet light in a flame in a combustion chamber by using a discharge phenomenon, and the ultraviolet light detector.
A microprocessor that measures the number of discharges and the discharge time due to the discharge phenomenon based on the detection output within a certain time after the ultraviolet irradiation to the light is cut off, and diagnoses the abnormality of the ultraviolet detector based on the measurement result; The combustion control device provided with.