JPS61213639A - Abnormality deciding method for flame detection pipe - Google Patents

Abstract

PURPOSE:To detect abnormality of flame detection pipes even during the stopping of a boiler and the fire-fighting and to prevent a time delay at the time of starting by detecting the stopping of the boiler and detecting that a check on the flame detection pipes is not made and then rendering a decision of the abnormality when the flame detection pipes discharge. CONSTITUTION:A check circuit 26 is actuated during the stopping of the boiler and the fire-fighting. In other words, in case after the confirmation is made that a shut-off valve of a lighting torch is shut off and further, the confirmation is made that the automatic or manual checking on the flame detection pipes is not made, one of the flame detection pipes self-discharges and a NOT circuit 36 outputs a signal 1 that a fire exists, an output signal of an AND circuit 32 becomes 1. Accordingly, the signal 1 is sent to a set terminal of an RS and FF circuit 23 from an OR circuit 22 and as the result, the signal 1 is outputted from the circuit 23 to an OR circuit 25 and an alarm signal indicating the abnormality of the flame detection pipe is outputted from the circuit 25. Accordingly, the abnormality of the flame detection pipe can be confirmed even during the stopping of the boiler or the fire-fighting at a central control room.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining abnormality in a flame detection tube used in a device for detecting the presence or absence of combustion in a boiler.

[Prior Art] A flame detection device uses a flame detection tube (ultraviolet discharge tube) as a sensor to detect ultraviolet rays emitted from a flame and determine the presence or absence of a flame.

Conventionally, the method shown in Figure 2 has been used to detect failures in the flame detection tube among the self-check functions that check whether the flame detection device is operating with normal functions. ing.

In the figure, 11 is an AND circuit, and this AND circuit 11 includes a shutter pulse that commands a close signal to the shutter that prevents ultraviolet rays from the flame from entering the flame detection tube, and a 24-hour timer to periodically The check pulse outputted to the A stage and the ON signal of the flame detection tube at the first corner of the A stage are respectively inputted. This AND circuit 11
The output of is inputted to an OR circuit 12. The OR circuit 12 is also configured to receive an output signal from an AND circuit at another corner. This OR circuit 1
The output signal of No. 2 is input to the set terminal of the RSS flip-flop circuit 13. A reset signal from a reset switch 14 is input to a reset terminal of this RSS flip-flop circuit 13. The output signal of the RSS flip-flop circuit 13 is input to an AND circuit 15. A power-off signal is input to the AND circuit 15 when the power to the flame detection tubes of each stage A, B, etc. is turned off.

That is, in this check circuit, a shutter close command is issued by a shutter pulse (step S1), and when a check pulse is output (step 32)
> and the ON signal is output from the flame detection tube (step 33), the AND circuit 11 outputs a flame detection tube abnormality signal. When this signal is input to the OR circuit 12, the OR circuit 12 outputs a "1" signal to the set terminal of the RS flip 70 tube circuit 13. Then, the RS flip 70 tube circuit 13 outputs a "1" signal to the OR circuit 15, and as a result, the OR circuit 15 outputs an alarm signal indicating an abnormality in the flame detection tube (step Sa). Note that an alarm signal is similarly output when the power to the flame detection tube is cut off (steps 84 to S7).

[Problems to be Solved by the Invention] In the conventional check circuit, the check function is operated periodically using a 24-hour timer, but the flame detection tube (flame detection method) deteriorates. If there is, self-discharge occurs when the boiler is started, which may result in an on signal, that is, a flame presence signal being output. As a result, the boiler cannot be started, and inspections and the like require time, resulting in a delay in startup time.

The present invention has been made in view of the above circumstances, and its purpose is to automatically detect abnormalities in the flame detection tube when the boiler is stopped or extinguished, and to prevent delays in starting the boiler. The purpose of this invention is to provide a method for determining abnormality of a flame detection tube.

[Means and effects for solving the problem] The present invention provides a method for determining an abnormality in a flame detection tube of a device that detects the presence or absence of combustion in a boiler using a flame detection tube that discharges in response to flame. In addition to detecting the stoppage of the boiler, it also detects that the flame detection tube is not checked, and when the flame detection tube discharges, it is determined that there is an abnormality and an alarm is issued. be.

With such a method, an abnormality in the flame detection tube can be detected even when the boiler is stopped or extinguished, and a time delay when starting the boiler can be prevented.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Fig. 1, 21 is an AND circuit, and this AND circuit 21 includes a shutter pulse that commands a close signal to the shutter that prevents ultraviolet rays from the flame from entering the flame detection tube, and a shutter pulse that is cycled by a 24-hour timer. The check pulse that is output as a signal and the ON signal of the flame detection tube at the first corner of the A stage are input. The output of this AND circuit 21 is input to an OR circuit 22. The OR circuit 22 is also configured to receive an output signal from an AND circuit at another corner. The output of this OR circuit 22 is input to a set terminal of an RSS flip-flop circuit 23. A reset signal from a reset switch 24 is input to a reset terminal of this RSS flip-flop circuit 23. The output signal of the RS flip 70 tube circuit 23 is input to an AND circuit 25. A power-off signal is input to the AND circuit 25 when the power to the flame detection tubes at each stage A, B, etc. is turned off.

The output signal of the rough check circuit 26 is input to the OR circuit 22. This check circuit 26 detects an abnormality in the flame detection tube when the boiler is stopped or extinguished. In this check circuit 26,
An ignition torch shutoff valve closing signal indicating whether the boiler is to be stopped or extinguished is input to the timer 31. This timer 31 delays the input signal for a certain period of time (15 seconds) and outputs a "1" signal to the AND circuit 32 when the close signal is input without interruption, thereby ensuring that the boiler stops. They are supposed to judge. Roughly speaking, in this check circuit 26, signals indicating whether the flame detection tube is being automatically checked or manually checked during boiler operation are input to the OR circuit 33, respectively. The output signal of the OR circuit 33 is delayed for a certain period of time (15 seconds) by a timer 34, and this signal is input to the AND circuit 32 via a NOT circuit 35. Furthermore, the output signals of all the flame detection tubes are input to the knot circuit 36.
When any flame detection tube is turned on, this knot circuit 3
6 outputs a “1” signal, and that signal is sent to timer 31.
After being delayed for a certain period of time (3 seconds), the signal is input to the input terminal of the AND circuit 32.

With this configuration, in the above check circuit,
While the boiler is operating, the same check operations as before are performed.

That is, when the shutter pulse closes the shutter command (step 31) and the check pulse is output (step S2), if the ON signal is output from the flame detection tube (step 33), the AND circuit is activated. A flame detection tube abnormality signal is output from 21. When this signal is input to the OR circuit 22, the OR circuit 22 outputs "1" to the set terminal of the RSS flip-flora circuit 23.
A signal is output. Then, the RSS flip-flora circuit 23 outputs a "1" signal to the OR circuit 25, and as a result, the OR circuit 25 outputs an alarm signal indicating an abnormality in the flame detection tube (step Ss).

On the other hand, the chinic circuit 26 operates while the boiler is stopped and when the fire is extinguished. That is, it is confirmed that the ignition torch cutoff valve is closed, that is, the boiler is stopped (step Sg), and the flame detection tube is automatically or manually checked (step S■).

811) is not performed, if any of the flame detection tubes self-discharges and the NOT circuit 36 outputs a "1" signal indicating that there is a flame, the output signal of the AND circuit 32 It becomes "1". Therefore, from the OR circuit 22
A “1” signal is sent to the set terminal of the SS flip-flora circuit 23, and as a result, a “1” signal is output from the RSS flip-flora circuit 23 to the OR circuit 25. This results in
An alarm signal indicating an abnormality in the flame detection tube is output from this OR circuit 25 (step Ss). Therefore, even when the boiler is stopped or the fire is extinguished, the operator can check for abnormalities in the flame detection tube in the central operation room.

[Effects of the Invention] As described above, according to the present invention, an abnormality in the flame detection tube can be detected even when the boiler is stopped or extinguished, thereby effectively preventing delays in starting the boiler. can do.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing the configuration of an abnormality check circuit for a flame detection tube according to an embodiment of the present invention, and Fig. 2 shows the configuration of a conventional abnormality check circuit for a flame detection tube. It is a block diagram. 21...AND circuit, 22...OR circuit, 23...
・R379717071 circuit, 25...OR circuit. ,
26...Check circuit.

Claims (1)

[Claims] In a method for determining an abnormality in a flame detection tube of a device for detecting the presence or absence of combustion in a boiler using a flame detection tube that discharges in response to flame, detecting a stoppage of the boiler, and
A method for determining an abnormality in a flame detection tube, comprising detecting that the flame detection tube has not been checked, and then determining an abnormality when the flame detection tube discharges.