JP3120009B2 - 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 for diagnosing failure of a flame detector and improper adjustment of a burner using a flame detection signal and detection data of a primary current of an ignition transformer.

[0002]

2. Description of the Related Art In a conventional combustion device such as a boiler, a spark is generated in a spark rod by an ignition current generated by an ignition transformer, and the spark ignites a gas of a pilot burner. Is ignited.

In addition, near the main burner, there is provided a flame detector including an ultraviolet detector for detecting the presence or absence of a flame generated by the main burner and the pilot burner.

In order to determine whether or not a flame detector and a flame detection circuit for detecting a flame of a main burner or the like of a combustion device are operating normally, a person operates a lighter or the like for smoking for example by igniting. Then, a method is employed in which the flame is brought close to the flame detector and a check is made as to whether or not a flame has been obtained by the flame detector. This method was dangerous and tedious because it had to be done by a person. In addition, in this method, the entire combustion device must be completely stopped during the check, which may cause a great deal of damage such as a long stoppage of the production equipment.

In order to determine whether or not a burner such as the main burner is normal so as not to stop the operation of the combustion device more than necessary, one burner is detected by two flame sensors, and these two burners are detected. There is also provided a system for forcibly stopping the operation of the burner when both flame sensors detect a fire. Further, there is also provided a system in which, even if one of the outputs is lost due to duplication of the flame sensor or the protection relay, if the output of the other is normally obtained, the combustion is continued and the apparatus is not stopped as much as possible.

[0006]

However, in such a conventional method for judging the failure of the flame detector, the burner does not operate until the combustion control operation locks out (forcibly stops the combustion device) due to misfiring or simulated flame. Not only is the failure of the flame detector unknown, but it is not possible to determine what caused this lockout, and the task of pursuing the cause was extremely troublesome and time-consuming. there were. In addition, the above-mentioned duplex system causes an increase in cost due to the duplication of the apparatus, an increase in the size of the apparatus, and an increase in instrumentation complexity.

For example, in lockout due to the occurrence of a fire, various causes such as failure of the flame detector, improper adjustment of the burner, and failure of the combustion control unit can be considered. Requires a great deal of time and experience, such as the need to inspect and replace individual equipment and parts, and repeat test runs.
There was a problem that the combustion device had to be stopped.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and detects a flame based on the primary current level of an ignition transformer and the presence or absence of an output of a flame detector at the time of ignition trial timing. It is an object of the present invention to provide a combustion control device capable of individually determining a failure of a heater, a flame detection circuit, an ignition transformer, and a defective burner adjustment.

[0009]

A combustion control apparatus according to the present invention supplies a flame detector for detecting a flame of a pilot burner or a main burner of a combustion apparatus and an ignition current to a spark rod facing the pilot burner. An ignition transformer and an ignition transformer primary current detection unit for detecting a primary current of the ignition transformer are provided. At an ignition trial timing, a microprocessor determines whether or not there is an output from the flame detector and a level of the primary current. Accordingly, it is determined whether the state of the flame detector and the ignition transformer and the adjustment state of the pilot burner and the main burner are normal.

[0010]

According to the combustion control device of the present invention, the presence or absence of a flame is detected by a flame detector and the ignition transformer
The primary current of the ignition transformer is detected by the secondary current detector,
At the ignition trial timing, it is determined that the flame detector is normal and the burner adjustment is defective when the level is at the spark level according to the level of the primary current, for example, on condition that a flame is detected. If the ignition level is lower than this level, it is determined that the flame detector has failed. If the ignition level has reached a lower level, it is determined that the ignition transformer has failed or the connection is incorrect.

[0011]

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 the combustion control device, 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 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. This detection 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 obtained from the relay output unit 6 to a microprocessor described later.

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

In particular, in the present invention, at the time of the ignition trial timing, the microprocessor 9 responds to the presence or absence of the frame current detection output from the frame current detection unit as the output of the flame detector and the level of the primary current. Then, it is determined whether the state of the flame detector and the ignition transformer and the adjustment state of the pilot burner and the main burner are normal.

Further, the microprocessor 9 has a function of receiving the above-mentioned contact feedback signal from the combustion sequence control relay 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 device to be diagnosed by the combustion control device of the present invention. In FIG. 2, reference numeral 21 denotes a fan for blowing air, and reference numeral 22 denotes a fan supplied to a main burner 25 through an air supply passage 21a. It is a damper that adjusts the air volume.

Reference numeral 23 denotes a damper motor for controlling the opening and closing of the damper 22, reference numeral 24 denotes two main valves (combustion valves) for controlling the flow rate of gas supplied to the main burner 25 through a gas passage 26, and reference numeral 27 denotes a gas passage 28. 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 disposed near the pilot burner 29, 31 denotes the above-mentioned ignition transformer for supplying an ignition current to the spark rod 30, and 32 denotes a main burner which is disposed near the main burner 25. And the above-described flame detector having a flame sensor and a flame detection circuit for detecting the flame of the pilot burner 29.

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. , Damper 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 standby, 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 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 driving circuit 2, and the flame detector 32 detects the flame of the main burner 25 and the pilot burner 29 and outputs the flame current based on a detection signal. 3 detects a frame current, and the detected output is also 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 section 6, and each relay controls on / off of the fuel control load.

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

For this reason, the microprocessor 9 executes data processing such as burner failure data, diagnoses burner failure, and the like by using the power supply voltage, the frame current, and the contact feedback signal as inputs, and stores the result in the memory 10. Or display on the display unit 11 or external output through the communication interface unit 12.

In this case, the microprocessor 9 determines whether the output of the flame detector 32 is present and the level of the primary current of the ignition transformer 31 shown in FIG. 4 according to the procedure shown in the flowchart of FIG. It is determined whether the states of the ignition detector and the ignition transformer and the adjustment states of the pilot burner and the main burner are normal.

First, the microprocessor 9 determines whether or not there is an output from the flame detector 32 based on the presence or absence of a frame current from the frame current detector 3 (step ST1). Has a flame detector drive circuit 2, a frame current detector 3, an analog /
A flame detection circuit and a flame detector 32 such as a digital converter 4
Is normal (step ST2).

On the other hand, if it is determined in step ST1 that there is no output of the flame detection signal, the microprocessor 9 then determines that the primary current of the ignition transformer 31 detected by the ignition transformer primary current detector 7 is It is determined whether or not the fuel is at the higher spark level shown in FIG. 4 (step ST3). If it is determined that the fuel is at the spark level, the burner has not been ignited, so the flame detector 32 and the flame detector 2
Are normal and the burner adjustment is determined to be defective (step ST4).

Next, if it is determined in step ST3 that the primary current is not at the spark level, then it is determined whether or not the primary current is at an ignition level lower than the spark level ( In step ST5), if it is determined that the ignition level is reached, the burner is actually ignited, but the flame detector 32 and the flame detection circuits 2 to 4 cannot detect the ignition. Detector 3
2 is determined to be a failure (step ST6).

Further, when it is determined in step ST5 that the primary current has not reached the ignition level or when the level is higher than spark, it is determined that the ignition transformer has failed (step ST7).

The electric current flows through the spark caused by the spark rod 30 due to the dielectric breakdown of the space. It takes a lot of energy to cause this breakdown. On the other hand, the conductivity of a flame is widely known, and when a spark is generated in a flame, the spark can be generated without requiring energy as compared with the above (dielectric breakdown). In other words, sparks in flames require less energy than sparks in empty spaces. The energy in this case appears as the primary current, that is, the magnitude of the consumed current. Therefore, when the primary current is at a high level equal to or higher than the spark level as shown in FIG. 4, the microprocessor 9 determines that the ignition transformer has failed due to a short circuit accident or the like.

Therefore, such a microprocessor 9
The failure diagnosis process according to the present invention makes it possible to easily pursue the cause of the failure, thereby providing an advantage that any person who is not a skilled person can easily perform the repair work by repairing, checking or replacing the failed part.

[0035]

As described above, according to the present invention, a flame detector for detecting a flame of a pilot burner or a main burner of a combustion device and an ignition transformer for supplying an ignition current to a spark rod facing the pilot burner are provided. And an ignition transformer primary current detecting unit for detecting a primary current of the ignition transformer, and at the time of ignition trial timing, the microprocessor determines whether the output of the flame detector is present and the level of the primary current according to the presence or absence of the flame detector. Since it is configured to diagnose whether the state of the flame detector and the ignition transformer and the adjustment state of the pilot burner and the main burner are normal, the level of the primary current of the ignition transformer and the flame detector at the time of the ignition trial timing. The output of the flame detector and ignition transformer Any number of individuals can determine failures and burner adjustment failures reliably and easily, and can quickly recover from failures, minimizing downtime for the entire combustion system and the resulting downtime for production equipment. Contributes to preventing the spread of damage by shortening In addition, there is an effect that it is possible to prevent an increase in cost due to the dualization of the combustion control device, an increase in the size of the device, and a complicated instrumentation.

[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 conceptual diagram showing a combustion device to be subjected to combustion control 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 an explanatory diagram showing a change in a primary current level of the ignition transformer according to the present invention.

FIG. 5 is a flowchart showing a procedure for diagnosing a failure of a flame detector and an ignition transformer and a diagnosis of good / bad burner adjustment according to the present invention.

[Explanation of symbols]

 7 Ignition transformer primary current detector 9 Microprocessor 25 Main burner 29 Pilot burner 30 Spark rod 31 Ignition transformer 32 Flame 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 Satoshi Kadoya 1-12-2 Kawana, Fujisawa-shi, Kanagawa Prefecture No. Takeshi Yamatake Honeywell Co., Ltd. Fujisawa Plant (56) References JP-A-63-156922 (JP, A) JP-A-2-157518 (JP, A) JP-A-52-133409 (JP, A) 8-145345 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23N 5/24

Claims (1)

(57) [Claims] 1. A flame detector for detecting a flame of a pilot burner or a main burner of a combustion device, an ignition transformer for supplying an ignition current to a spark rod facing the pilot burner, and a primary current of the ignition transformer An ignition transformer primary current detection section, and at the time of ignition trial timing, the state of the flame detector, the flame detection circuit, the state of the ignition transformer, and the pilot burner according to the presence or absence of the output of the flame detector and the level of the primary current. And a microprocessor for diagnosing whether the adjustment state of the main burner is normal or not.