JP2550855Y2 - Flame detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame detector.

[0002]

2. Description of the Related Art Boiler burner combustion state (flame or not)
Conventionally, an optical flame detector is used to detect flickering of flame light.

An example of such a flame detector is shown in FIG.
In the drawing, reference numeral 1 denotes a flame detector provided with a converging convex lens 2 and an optical fiber cable 3 for transmitting collected light, 4 denotes a burner for fuel injection, and 5 denotes a fuel injected from a plurality of injection holes of the burner 4. Is a flame formed by burning.

In order to detect the presence or absence of the flame 5 based on the flicker of light of the flame 5 by the flame detector 1, it is conceivable that all the flames 5 fall within the field of view 6 of the convex lens 2. In this case, due to the characteristics of the convex lens 2, the cross section of the field of view spreads widely in a conical shape as shown at 7 in FIG. 4 , so that the flame detector 1 sees a wide area. .

On the other hand, the flickering of light is the flickering of light caused by the burning of small fuel lumps sparsely present in the flame 5, and when the flame detector 1 looks at a wide area of the flame 5, , Affected by the reflected light from the furnace wall,
The energy level that becomes noise in the collected light increases , and the flickering light that exists sparsely in the field of view
The number increases, and thus the light of the converged and averaged flame 5
The change in the intensity of the fluctuation is the change in the intensity of the light of each flame 5
In comparison, it is difficult to reliably grasp the flicker of the light of the flame 5.

Therefore, conventionally, in order to view the flicker of the light of the flame 5 in a narrow area, one of the many flames 5 is aimed at, and the flicker of the light of the flame 5 is detected by the flame detector 1.
In this case, since the energy level that becomes noise in the collected light is low, the flicker of the light of the flame 5 can be detected relatively reliably .

[0007]

However, the combustion position of the flame 5 changes due to fluctuations in the pressure of the fuel injected from the burner 4 and the like, and is not constant. When trying to detect the flicker of light, the flame 5 may fall out of the field of view of the flame detector 1, and the flicker of light may not be detected.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention makes it possible to easily and reliably detect the flicker of light from all flames by observing all flames in a wide area with a narrow and narrow view. It was done for the purpose.

[0009]

The present invention comprises a cylindrical lens 8 and an optical fiber cable 3 for transmitting light condensed by the cylindrical lens 8 , and the fuel injected from a plurality of injection holes of the burner 4 burns. In the flame detector 1 capable of detecting the flickering of the light of the generated flame 5, the visual field formed by the cylindrical lens 8
Field of view 10 in the direction of major axis 11b in field of view section 11 at 10
Outer diameter of a flame bundle 5a formed by a plurality of flames 5 inside
D is formed and formed by the cylindrical lens 8.
Minor axis 11a direction both visibility section 11 in view 10
The cylindrical lens 8 is moved to the outer cylindrical surface so that the surface of the field of view 10 on the side crosses each flame 5 in the radial direction d of the flame 5.
It is arranged near the burner 4 toward the flame 5 .

[0010]

The field of view formed by the cylindrical lens 8
Field of view on both sides in the direction of short axis 11a of field of view section 11 at 10
Since the surface of the 10 cuts the respective flame 5 in the radial direction d of the flame 5, flame volume 12 to be detected becomes smaller. Thus, the present hand
In the stage, the detected flame volume is large and flickering.
The flickering of individual light causes the flickering of other light
As a result, the effect of flicker is reduced.
When the flame volume is large where the change in flicker is detected.
Light flickering increases and the flame 5 as compared with focus is easily and reliably detected. An outer diameter portion D of a flame bundle 5 a formed by a plurality of flames 5 is formed by a cylindrical lens 8.
Long axis 11b of field of view 11 in field of view 10 to be formed
Because it is within the field of view 10 of the direction, the light of all the flames 5 can be easily and reliably flickered by one set of the flame detectors 1.
And clearly detected.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.
Denotes a cylindrical cylindrical lens 8 whose outer peripheral cylindrical surface is directed to the flame 5, a plano-convex lens 9 for condensing light from the cylindrical lens 8, and an optical fiber for transmitting light from the plano-convex lens 9. It has an inverted cable 3.

In the drawing, reference numeral 10 denotes a cylindrical lens 8
Is a field of view of an elongated elliptical shape surrounded by the field of view 10 in which the short axis 11a is short and the long axis 11b is long, and the cylindrical lens 8 is within the field of view 10 in the long axis 11b direction. In addition to capturing the outer diameter portion D of the flame bundle 5a in which all the flames 5 distributed over a wide area are collected,
The surfaces of the field of view 10 on both sides of the field of view section 11 in the direction of the short axis 11a cross each flame 5 in the radial direction d to form a small flame volume 12 trapped in the field of view 10. It is arranged with a plano-convex lens 9 in the vicinity.

As shown in FIG. 2, the axis of the cylindrical lens 8 is l ₁ , the axis of the burner 4 is l ₂ , and the axes l ₁ and l ₂ are set to the axis l ₃ of the plano-convex lens 9. On the other hand, when projected on a plane 13 (see FIG. 3) which is orthogonal to each other to make l ₁ ′ and l ₂ ′ respectively , the axis l ₁ ′ and the axis l ₂ ′ are not orthogonal.
Thus for, when the axis l ₁ 'and l _2' are perpendicular,
As shown in FIG. 2, the major axis 11b direction of the sight section 11 in view 10 (see FIG. 1) of the axial l ₂ direction of the burner 4
Now it faces, Ru can be captured in the field of view in the 10 flame
The number of 5 is because there is no low.

It should be noted that the lens is formed by a cylindrical lens 8.
The view section 11 to be formed into an elongated ellipse
In the lens 8, the light is transmitted through the cylindrical lens 8.
Is refracted in the circumferential direction, but in the longitudinal direction of the cylinder (the axis l in FIG. 2).
_This is because it is not refracted in _one direction).

The direction of the major axis 11b of the view section 11 is
The diametrical direction of the cylindrical lens 8 and
Of the short axis 11a is the axis l of the cylindrical lens 8.
_The direction parallel to ₁ and the part of the cylindrical lens 8
If it is illustrated in a minute, the orientation is as shown in FIGS. Sand
A becomes the direction of the major axis 11b of the view section 11, and
This is the direction of the short axis 11a of the view section 11.

At the time of detection, the light of the flame 5 is condensed by the cylindrical lens 8 and sent to the processing section through the plano-convex lens 9 and the optical fiber cable 3 to determine the degree of flickering of the light and the presence or absence of the flame.

In the above embodiment, the short axis 11
As is clear from FIG. 1 , the surfaces of the field of view 10 on both sides in the a direction cross all the flames 5 obliquely to the direction in which the flames 5 extend, and the direction of the short axis 11 a of the field of view cross section 11 . Since the width of the field of view 10 is narrow, the field of view 1 in the direction of the short axis 11a
The individual flame volumes 12 delimited by 0 are smaller. Visibility Thus, after the energy level as a noise in the light that is focused on the cylindrical lens 8 is lowered
The number of light flickers present in the
As a result, the individual light
Flicker is less affected by other light flicker
Therefore, the intensity of flicker of the flame light
The change is greater than in the conventional case, and the flickering of the light of the flame 5 becomes clear and can be detected easily and reliably.

Further, since the field of view 10 in the direction of the major axis 11b of the field of view section 11 can capture the outer diameter portion D of all the flames 5, the light of all the flames 5 is flickered by one set of the flame detectors 1. As a result, the presence or absence of the flame 5 of the burner 4 can be reliably detected. Therefore, when the flame detector 1 of the present embodiment is applied to the flame safety equipment of a boiler, the safety is significantly improved.

In the embodiment of the present invention, the case where the cylindrical lens is combined with the plano-convex lens has been described.
In addition, it goes without saying that various changes can be made without departing from the gist of the present invention.

[0021]

According to the flame detector of the present invention, there is an excellent effect that the flicker of light of all the flames distributed over a wide area can be easily, reliably and clearly detected by one set of flame detectors. obtain.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a flame detector according to the present invention.

FIG. 2 is a perspective view for explaining the basis for determining the direction of the cylindrical lens in the flame detector of the present invention.

FIG. 3 is a perspective view for explaining the directions of the axis of the cylindrical lens and the axis of the burner when the direction of the cylindrical lens is determined in the flame detector of the present invention.

FIG. 4 is a perspective view of an example of a conventional flame detector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Flame detector 3 Optical fiber cable 4 Burner 5 Flame 5a Flame bundle 8 Cylindrical lens 10 Field of view 11 Field of view section 11a Short axis 11b Long axis D Outside diameter of flame bundle d Radial direction

Claims (1)

(57) [Scope of request for utility model registration] 1. A fuel supply system comprising a cylindrical lens (8) and an optical fiber cable (3) for transmitting light collected by the cylindrical lens (8) , wherein fuel injected from a plurality of injection holes of a burner (4) burns. In the flame detector (1) capable of detecting the flicker of light of the generated flame (5) , the flame is formed by the cylindrical lens (8).
The major axis (11 ) of the field of view (11) in the field of view (10)
The field of view (1) formed by the cylindrical lens (8) while capturing the outer diameter (D) of the flame bundle (5a) formed by the plurality of flames (5 ) in the field of view (10) in the direction b).
0) Both sides in the short axis (11a) direction of the view section (11)
The cylindrical lens so that the surface of the side view (10) crosses each flame (5) in the radial direction (d) of the flame (5).
Burner (8) with the outer cylindrical surface facing the flame (5)
(4) A flame detector, which is disposed in the vicinity.