JPH0875152A - Flame detector - Google Patents

Abstract

(57) [Summary] [Purpose] The amount of incident light from the detection window can be adjusted to an appropriate amount, thereby enabling appropriate flame detection. [Structure] In a flame detection device 1 for detecting a flame 6 based on a light beam 7 incident from a detection window 4, the detection window 4 is provided with a diaphragm mechanism 10 for adjusting the opening degree of the detection window 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame detecting device used for monitoring a burner flame in a combustion furnace, for example.

[0002]

2. Description of the Related Art For example, in a combustion furnace, the strength of a burner flame is detected, and combustion control is performed according to the detection result. In this case, the intensity of the flame is detected by a photoelectric tube that outputs a signal according to the amount of light incident from the detection window of the flame detection device.

As a conventional example of a flame detecting device using this type of phototube, there is known one disclosed in Japanese Patent Publication No. 4-42568. In this flame detection device, a shutter that operates according to the detection result of the photoelectric tube is provided in the detection window, the shutter opens and closes the incident optical path to the photoelectric tube, and based on the opening and closing operation result and the output of the photoelectric tube, the burner side or It is designed to detect anomalies on the phototube side.

[0004]

By the way, depending on the scale and type of combustion equipment, the amount of light incident on the photocell from the detection window may exceed the photocell's ability, and in that case, due to the influence of diffuse reflection or the like. There was a case where the proper detection ability could not be exhibited. Further, in the case where the shutter is arranged in the detection window like the flame detection device of the above-mentioned conventional publication, since the peripheral mechanism of the shutter is provided with a play and a gap so as to correspond to the thermal environment, operating conditions, etc., the detection window If the amount of incident light from is more than the appropriate amount, light may leak from the shutter part due to irregular reflection etc. and enter the phototube, and there is a possibility that light may be erroneously detected even if the shutter is closed, and it may not be possible to correctly detect abnormalities. there were.

The present invention has been made to solve the above-mentioned problems, and the amount of incident light from the detection window can be adjusted to an appropriate amount, thereby enabling proper flame detection. The purpose is to obtain a detection device.

[0006]

A flame detecting apparatus according to the present invention is characterized in that a detection mechanism for adjusting the opening degree of the detection window is provided in the detection window through which light rays from the flame enter.

[0007]

In the flame detecting apparatus according to the present invention, the aperture degree of the detection window can be adjusted by operating the diaphragm mechanism, so that the amount of light incident from the detection window can be adjusted to an appropriate amount.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of a combustion control device 2 including a flame detection device 1 according to an embodiment of the present invention. This flame detection device 1 has a detection window 4 at the front end of a closed box-shaped housing 3.
The light beam 7 from the flame 6 of the burner 5 that enters through the detection window 4 is photoelectrically converted by the photoelectric tube (ultraviolet ray detection tube) 8 and output as an electric signal. Inside the detection window 4, a shutter mechanism 9 for opening and closing the optical path to the photoelectric tube 8 is arranged,
A diaphragm mechanism 10 that is adjusted according to the scale of the burner 5 at the time of installation is arranged outside the detection window 4. The diaphragm mechanism 10 adjusts the degree of opening of the detection window 4 (the size of the opening or the opening ratio).

In this combustion control device 2, the flame detection device 1
Is input to the flame detection circuit 11, and the presence or absence of flame and its strength are detected here. The signal from the flame detection circuit 11 is input to the shutter drive circuit 12 and the combustion control circuit 13. The shutter drive circuit 12 includes the flame detection circuit 11
The opening / closing control of the shutter mechanism 9 is performed according to the signal. The combustion control circuit 13 controls the combustion state of the burner 5 according to the signal from the flame detection circuit 11. Also, the shutter drive circuit 1
The output signal of 2 is input to the abnormality detection circuit 14, and the abnormality detection circuit 14 detects an abnormality of the burner 5 or an abnormality of the photoelectric tube 8 depending on the operating state of the shutter mechanism 9 or the state of flame, and detects the abnormality. If the alarm is issued.

In this apparatus, when a strong light beam is input from the detection window 4 due to the play and gap of the shutter mechanism 9, the photoelectric tube 8 may be erroneously detected due to irregular reflection of the light beam, but the diaphragm mechanism 10 should be adjusted. As a result, the amount of incident light from the detection window 4 can be adjusted to an appropriate amount, and this fear is eliminated. Also, since the amount of incident light can be adjusted to an appropriate amount,
The flame detection device 1 can be adjusted to a state suitable for the combustion equipment, and proper detection capability can be exerted.

FIG. 2 shows a specific example of the configuration of the flame detection device 1. (A) is a side view showing an external appearance, and (b) is a front view. In this device, there is a detection window 4 on the front surface of the housing 3 (the detection window itself cannot be seen from the outside).
A diaphragm mechanism 10 is provided at the front part of the. Aperture mechanism 10
As for the diaphragm mechanism of any kind, as long as it adjusts the opening degree of the detection window 4, such as one that adjusts the central hole diameter by cooperatively driving a large number of movable thin plates as used in a camera. May be used. Here, the operation unit 1
The aperture amount can be adjusted by moving 8. It should be noted that adjustment of the diaphragm can be done only at the time of installation, so
The operation portion 18 can be fixed after adjustment.

FIG. 3 is a perspective view showing the internal structure of the flame detection device 1, and FIG. 4 is a schematic view of the main parts thereof. A photoelectric tube 8 is arranged inside the housing 3 of the flame detection device 1, and the tip of the photoelectric tube 8 is exposed from the hole 19a of the light shielding plate 19 toward the detection window 4 side. The shutter mechanism 9 includes a shutter 20 having a spring plate shape that opens and closes an optical path from the detection window 4 to the photoelectric tube 8, and the shutter 2.
The shutter 20, which is configured to open and close 0 to drive the solenoid 21, is elastically deformed around the base support point 22 as a fulcrum in accordance with the operation of the plunger 21a of the solenoid 21 to move from the detection window 4 to the photoelectric tube 8. It opens and closes the optical path leading to it. In FIG. 4, reference numeral 23 is a stopper that determines the upper limit position of the shutter 20, and
It is provided at the lower end of 9.

In this specific example, the amount of incident light from the detection window 4 can be adjusted by adjusting the diaphragm mechanism 10, and even if the shutter 20 has a structure with a lot of play and gaps,
The amount of light leaking from the shutter 20 and entering the photoelectric tube 8 can be reduced, and the risk of erroneous detection can be eliminated.

[0014]

As described above, according to the present invention, the aperture degree of the detection window can be adjusted by the diaphragm mechanism,
As a result, it is possible to properly detect the flame according to the combustion equipment to be measured. Therefore, even when a shutter is provided to detect an abnormality, there is no possibility of erroneous detection.

[Brief description of drawings]

FIG. 1 is a system diagram of a combustion control device including a flame detection device according to an embodiment of the present invention.

2A and 2B show a specific example of a flame detection device according to an embodiment of the present invention, in which FIG. 2A is an external side view and FIG. 2B is a front view.

FIG. 3 is a perspective view showing the internal structure of the flame detection device shown in FIG.

FIG. 4 is a schematic side view showing an enlarged main part of FIG.

[Explanation of symbols]

 1 Flame Detection Device 4 Detection Window 6 Flame 7 Rays 10 Aperture Mechanism

Claims (1)

[Claims] 1. A flame detection device for detecting a flame based on a light beam incident from a detection window, wherein the detection window is provided with a diaphragm mechanism for adjusting an opening degree of the detection window. .