KR20090007631U - Ultra-violet sensor for detection of flame - Google Patents

Abstract

As a flame detector for detecting a flame when a fire occurs, a method of detecting ultraviolet rays or mid infrared rays (MID INFRARED RAY) is used. The present invention relates to the shape and structure of the ultraviolet sensor used in the flame detector. Conventional commercialized UV sensor is a photoelectric tube using photoelectric effect, and since its size and shape is large and only a specific shape is produced, it has a disadvantage of not being able to make a small flame detector using it. .

The present invention, in order to overcome the above disadvantages and to make the flame detector even smaller, newly developed the shape and structure of the ultraviolet sensor for flame detection.

UV detection sensor for flame detection of the present invention,

A flame detection window 19 for transmitting ultraviolet rays for transmitting ultraviolet rays generated by an external flame into the sensor;

Cylindrical side housing 20 for protecting the inside of the sensor,

Disc-shaped lower housing 22 for protecting the inside of the sensor,

A positive lead wire 23 which attracts photoelectrons emitted from the negative electrode plate 24 by adding a positive voltage,

A negative electrode plate 24 that emits photoelectrons when ultraviolet rays arrive,

It is connected to the negative electrode plate 24, and comprises a negative electrode lead wire 25 for adding a negative voltage (-) to emit photoelectrons from the negative electrode plate 24.

Fire prevention, fire detector, flame detector, ultraviolet sensor, photoelectric effect

Description

ULTRA-VIOLET SENSOR FOR DETECTION OF FLAME

Fire detectors used in the field of firefighting and disaster prevention are classified into heat detectors, smoke detectors, and flame detectors. The heat detector detects heat or temperature around the fire detector to determine whether a fire has occurred. Smoke detectors detect smoke particles in the air entering the smoke detector, and flame detectors detect the light rays emitted from the flames.

The flame detector is a fire detector using a flame detection sensor that detects mid-infrared or ultra-violet emitted from a flame caused by a fire.

The present invention relates to an ultraviolet detection sensor among the flame detection sensor used in the flame detector.

The principle of a flame detector, a kind of fire detector, is to detect light emitted from a flame.

FIG. 1 illustrates a blackbody radiation wavelength WAVELENGTH according to temperature. The horizontal axis represents the wavelength distribution of the emitted energy, and the vertical axis represents the intensity of the energy (INTENSITY). Blackbody radiation, in theory, refers to energy release properties determined only by the material's temperature. In FIG. 1, the wavelength constituting the energy emitted by a black body having a temperature of 310 K (K is an absolute temperature) and a wavelength when the temperature is increased to 3000 K are very large. First, as the temperature increases, the absolute amount of energy emitted at each wavelength increases. And the wavelength showing the highest intensity shifts toward the shorter side. In the wavelength-by-wavelength distribution of the energy emitted by a black body of 310K, intensity can hardly be measured at wavelengths shorter than 1 micrometer. It can be seen that the wavelength in the ultraviolet region below is also emitted.

The wavelengths included in the energy emitted from the sparks generated when the material burns are similar to those of FIG. 1. If the flame temperature of the flame is high or the flame intensity is high, the absolute intensity of the emitted wavelength increases, and the wavelength of the highest intensity is shifted toward shorter wavelengths such as visible or ultraviolet rays.

Flame detectors, which are used commercially in the field of firefighting and disaster prevention, measure the change in intensity of specific wavelengths of light emitted when a material burns to determine the occurrence of a flame. Flame detectors used in flame detectors include mid-infrared and ultraviolet sensors. As described above, the wavelength emitted from the flame includes infrared rays, visible rays, ultraviolet rays, and the like, but in general, the visible rays are not used to determine the presence or absence of the flame. This is because there is visible light emitted from the sun and reaching the surface around the flame detector installed at the industrial site, and the visible light is changed greatly.

Therefore, in order to determine the presence or absence of a flame, a change in the amount of light in the mid-infrared region and a change in the amount of light in the ultraviolet region are detected to determine whether or not a flame is generated.

Since the present invention relates to the ultraviolet sensor among the sensors for detecting the flame, only the operating principle of the ultraviolet sensor will be described.

2 illustrates a basic principle of an ultraviolet sensor using a photoelectric effect. When ultraviolet rays, X-rays, or gamma rays, which have short wavelengths, are exposed on a metal surface (metal plate), electrons are emitted from the metal surface. This phenomenon is called a photoelectric effect. The photoelectric effect is emitted only by light above a certain frequency (limit frequency), and when the light frequency is greater than a certain frequency, the photoelectron emits immediately after the light is exposed, no matter how weak the light intensity. In addition, when the light of the same frequency is exposed, the intensity of photocurrent by the photoelectrons is proportional to the intensity of the incident light. In FIG. 2, when light (photons) having a specific wavelength reaches the metal plate (cathode plate), photoelectrons are emitted from the metal plate. The emitted photoelectrons move to the anode where the (+) electricity is applied. Before the photoelectrons were emitted, there was no current flow between the anode and the cathode, but as the photoelectrons move from the cathode to the anode, a closed circuit is formed through which the current flows. At this time, the current flowing between the two poles can be measured to determine the presence and intensity of light at a specific wavelength (specific frequency) reaching the cathode.

As above, the flame detection ultraviolet sensor utilizes a photoelectric effect that selectively emits photoelectrons only for light of very short wavelengths, such as ultraviolet light.

3 shows a characteristic of a UV sensor for flame detection having a product name, UV TRON, commercially developed by HAMAMATSU, Japan. The flame-sensing ultraviolet sensor generates photoelectrons at wavelengths between 180 and 260 nanometers, which do not interfere with sunlight, among the wavelengths emitted from the flame. As already mentioned above, the photoelectric effect generates a photoelectric effect immediately for light of a certain frequency (wavelength), no matter how weak the amount of light. Thus, the sensor does not generate photoelectric effects on sunlight and light in commercial lamps, but selectively generates photoelectric effects only in the fragile ultraviolet region generated by the combustion of a material.

4 is a real photograph of a product having the characteristics of FIG. 3. The bent electrode that looks like a clip on the front is the anode, and the metal plate on the back is the cathode, and the two electrodes are separated at regular intervals. In addition, the two electrodes are installed inside the glass tube and are sealed from the outside atmosphere because the glass tube is sealed.

FIG. 5 is a diagram of a real photograph of FIG. 4. It is 9 millimeters in diameter and 56 millimeters in length. The portions indicated by dotted lines are the negative electrode plates 2 and 7 and the positive electrode 3 and 6. The metal plate, the negative plate, is made of metals such as zinc, cesium, antimony and the like. The size of the negative plate is 12 millimeters wide and 5 millimeters long, with an area of 60 square millimeters. The anode and cathode plates are sealed inside a tube (TUBE) 1 through which ultraviolet rays are transmitted, so that they do not come into contact with the outside atmosphere. The positive electrodes 3 and 6 are connected to the positive lead wire 4, and the negative electrode plates 2 and 7 are connected to the negative lead wire 5.

FIG. 6 is a photograph of an external appearance of a microcontroller MICRO CONTROLLER 8 inside a FLAME DETECTOR developed using the ultraviolet sensor 9 of FIG. 5. The invisible back of this picture is equipped with a microprocessor and electronics. As can be seen from this photograph, the length of the ultraviolet sensor 9 is slightly smaller than that of the circular microcontroller 8. That is, the length of the ultraviolet sensor 9 acts as a constraint so that the size of the microcontroller 8 cannot be made small. Even if the microcontroller 8 is to be made smaller, the ultraviolet sensor has a long shape in the longitudinal direction, so that the circular circular microcontroller 8 can no longer be made small.

FIG. 7 is a view showing a cross section of the ultraviolet flame detectors on which the ultraviolet sensors 9 and 13 and the microcontrollers 8 and 14 of FIG. 6 are mounted. As can be seen from the figure, when the negative electrode plate of the ultraviolet sensor 13 that receives light is located in the center of the flame detection window WINDOW 11 where the light at the bottom of the sensor is incident, the diameter of the flame detector is no longer made smaller. Can't.

In the present invention, in order to further reduce the size of the flame detector, the shape of the ultraviolet sensor used in the flame detector is improved.

FIG. 8 is a diagram comparing the shapes of the ultraviolet sensor 18 for detecting the flame of the conventional Japanese Hamamatsu Corporation and the ultraviolet sensor 17 of the present invention. The ultraviolet sensor 17 of the present invention on the left has a square shape in which the negative electrode plate (metal plate) is 8 millimeters wide and 8 millimeters long, and the area of the negative electrode plate is 64 square millimeters. The negative electrode plate of the ultraviolet sensor 18 of Hamamatsu Corporation is 12 millimeters in width and 5 millimeters in length, and the area of the negative electrode plate is 60 square millimeters. The negative plate is a part that receives light from the outside, and as the area becomes larger, it can receive a lot of light, thereby increasing sensitivity. In the present invention, it can be seen that the negative electrode plate area of the ultraviolet sensor 17 for flame detection is somewhat larger than the negative plate area of the ultraviolet sensor 18 of Hamamatsu.

9 shows the detailed shape of the flame-detecting ultraviolet sensor devised in the present invention. The size of the ultraviolet sensor of Hamamatsu, Japan, shown in Fig. 5, is 9 millimeters in diameter, 56 millimeters in length, and 60 square millimeters in area of the negative electrode plate. The size of the ultraviolet sensor of the present invention shown in FIG. 9 is 23 millimeters in diameter, 8 millimeters in length (height), and the area of the negative electrode plate is 64 square millimeters. That is, although the diameter was somewhat larger and the length was smaller than 1/5 or less, it can be seen that the area of the negative electrode plate for determining the sensitivity was rather large.

9 and 10, using the flame detection UV detection sensor of the present invention, as shown in Figures 11 and 12 it is possible to develop a small microcontroller 32 of the flame detector. As a result, the development and manufacture of the compact flame detector 37 becomes possible. In addition, the outer size of the ultraviolet sensor for flame detection is small, but by increasing the negative electrode plate 24 there is an effect that can increase the sensitivity by increasing the light receiving area for receiving light.

The ultraviolet detection sensor for flame detection of the present invention, the flame detection window 19, the cylindrical side housing 21, the disk-shaped lower housing 22, the anode lead wire 23, the cathode plate 24 as shown in FIG. And the negative lead 25.

10, the flame detection ultraviolet ray detection sensor of the present invention has a flame detection window 19 through which light incident from a flame passes is positioned at the top thereof, and is spaced 4 to 5 millimeters below the flame detection window 19. The positive lead wire 23 is positioned, and the negative electrode plate 24 is positioned below the positive lead wire 23 by 0.5 to 1.5 millimeters. The negative lead 25 is welded to the lower part of the negative electrode plate 24 in a parallel direction. The disk-shaped lower housing 22 is positioned below the cathode lead wire 25 by 2 to 3 millimeters. Cylindrical side housing 21 is enclosed in the side surface of the flame detection window 19 and the disk-shaped lower housing 22, and is sealed inside. When projecting the inside of the sensor vertically through the flame detection window 19 from the outside of the sensor, the center of the flame detection window 19, the negative electrode plate 24, the cylindrical side housing 21, and the disc shaped lower housing 22 Placed to match.

The flame detection window 19 is made of single crystal sapphire or a special material having high UV transmittance, and has a transparent disc shape having a diameter of 20 millimeters and a thickness of 1 millimeter.

The cylindrical side housing 21 and the disc lower housing 22 may use a metal of stainless material or a post-treated material such as nickel plating so as not to rust on a metal of cheap material such as brass or plain steel. . In addition to metals, it is also possible to use a polymer material which is electrically insulated, such as plastic, of various materials.

The cylindrical side housing 21 is a cylinder about 23 millimeters in diameter and about 7.5 millimeters in height, and the top and bottom planes of the cylinder are open. The open top is provided with a flame sensing window 19 through which light rays from the flame can pass and can be joined with an adhesive 20. In the open bottom, the disc-shaped lower housing 22 is bonded with the adhesive 27. At this time, the adhesives 20 and 27 used were materials that withstand 50 degrees Celsius or more. By bonding the flame detection window 19 and the disc-shaped lower housing 22 to the top and bottom of the cylindrical side housing 21, the sensor becomes a hermetic structure.

In FIG. 10, an anode lead wire 23, a cathode plate 24, a cathode lead wire 25, and the like are provided inside the ultraviolet sensor for spark detection according to the present invention.

The material of the anode lead wire 23 is a metallic electric conductor, and is made of one strand of 0.5 to 1.0 millimeters in thickness. The anode lead wire 23 is bent in a spiral clip shape as shown in the plan view of FIG. 9, is wound spirally from the inner side to the outer side, and goes about 3 to 4 millimeters after rotating one and a half turns. At this time, the bent portion in the shape of a spiral clip should be a shape that does not escape the edge of the square negative electrode plate (24). The anode lead wire 23 straight after being bent in a clip shape is bent again in a direction perpendicular to the imaginary plane formed by the spiral clip lead wire. The bent positive lead wire 23 passes again through the disk-shaped lower housing 22 and is exposed to the outside of the sensor. The anode lead wire 23 exposed to the outside is bonded to the disk-shaped lower housing 22 and the adhesive 26 so that the inside of the sensor is sealed and disconnected from the outside.

The negative electrode plate 24 is manufactured using a material having a good photoelectric effect by ultraviolet rays such as zinc, cesium, or antimony. Square cathode plates are 8 millimeters wide on one side and about 1 millimeter thick. One side of the negative electrode plate serves to receive light, and the negative lead 25 is welded in parallel to the center of the opposite side.

The material of the negative lead 25 is also a metallic electric conductor, and is made of a single strand of 0.5 to 1.0 millimeters in thickness. The negative electrode lead 25 is welded in a direction parallel to the negative electrode plate 24 and is bent vertically after going straight about 4 to 5 millimeters from the welded portion. The bent negative lead 25 passes through the disk-shaped lower housing 22 and is exposed to the outside of the sensor. The negative lead 25 and the disk-shaped lower housing 22 are joined together with an adhesive 26 so that the inside of the sensor is sealed and disconnected from the outside.

The anode lead wire 23 and the cathode lead wire 25 inside the sensor are exposed to the outside through the disc-shaped lower housing 22. The two lead wires 23 and 25 exposed to the outside are symmetrically spaced about 6 to 7 millimeters from the center point of the disc-shaped lower housing 22.

The gap between the positive electrode lead wire 23 and the negative electrode plate 24 may be appropriately selected between 0.5 and 1.5 millimeters depending on the intended use. In order to attract the photoelectrons generated from the negative electrode plate 24 to the positive electrode, a high voltage is applied between the positive electrode 23 and the negative electrode plate 24, and between the positive electrode 23 and the negative electrode plate 24 according to the magnitude of the voltage used at this time. The gap between must be adjusted. The higher the voltage, the larger the gap, and the lower the voltage, the smaller the gap. If the gap is small, the photoelectrons can be attracted even at a low voltage. However, if the gap is too small, a discharge occurs between the anode 23 and the cathode plate 24 even when external light is not incident, thereby measuring photoelectrons due to sparks. It becomes impossible. Therefore, the gap should be appropriately set according to the material of the anode lead wire 23 and the material of the anode plate 24.

The interior of the sensor may be sealed with a vacuum, or may fill and seal a particular gas. When fabricated in vacuum, the characteristics of the photoelectric effect are good, and a photoelectric effect linearly proportional to the intensity of incident light can be obtained. In contrast, when a special gas such as argon or neon is filled inside the sensor, a higher photoelectric effect may be obtained than when sealed with a vacuum, but a photoelectric effect is not linearly proportional to the intensity of incident light. When the special gas is filled, photoelectrons from the negative electrode plate can ionize the special gas to create more electron flow (photocurrent). Depending on the application purpose of the flame detection ultraviolet sensor, the inside of the sensor may be sealed with a vacuum or a special gas may be filled and sealed.

BRIEF DESCRIPTION OF THE DRAWINGS The graph explaining the change of the black body radiation wavelength according to the temperature of a black body.

2 is a diagram for explaining the principle and configuration of the photoelectric effect.

Figure 3 is a graph showing the detection characteristics according to the wavelength of the conventional commercialized UV sensor for flame detection.

Figure 4 is a photograph of the conventional commercialized ultraviolet sensor for flame detection.

5 is a detailed view of a commercialized flame detection ultraviolet sensor shown in FIG.

FIG. 6 is a microcontroller photograph of a flame detector commercialized using the flame detection ultraviolet sensor shown in FIGS. 4 and 5. FIG.

FIG. 7 is an internal structure diagram of a flame detector equipped with the microcontroller of FIG. 6.

8 is a comparative view of the ultraviolet light sensor 17 for detecting the flame of the present invention, and the existing ultraviolet light sensor 18 for flame detection.

9 is a detailed view of the ultraviolet detection sensor for flame detection of the present invention.

10 is a detailed front view of the ultraviolet ray sensor for flame detection of the present invention.

11 is an internal structure diagram of a flame detector using the ultraviolet detection sensor for flame detection of the present invention.

12 is a comparison of the flame detector 35 to which the conventional commercialized ultraviolet sensor 18 is applied, and the flame detectors 36 and 37 to which the ultraviolet detection sensor 17 of the present invention is applied.

Explanation of symbols on the main parts of the drawings

1: Tube for UV transmission (TUBE) 2: Cathode plate (CATHODE)

3: ANODE 4: Anode lead wire (LEAD)

5: cathode lead wire 6: anode

7: negative electrode plate 8: flame detector microcontroller

9: ultraviolet sensor for flame detection 10: outer case of flame detector

11: wind detection window 12: incident light from external flame

13: ultraviolet sensor for flame detection 14: flame detector microcontroller

15: external signal connection terminal 16: ceiling or mounting wall

17: UV detection sensor for flame detection of the present invention

18: UV detection sensor for flame detection

19: flame detection window (WINDOW) 20: adhesive

21: cylindrical side housing (HOUSING) 22: disk-shaped lower housing

23: anode lead wire (LEAD) 24: cathode plate (CATHODE PLATE)

25 cathode lead wire 26 adhesive

27: adhesive 28: flame detector outer case

29: flame detection window 30: incident light from an external flame

31: UV detection sensor for flame detection 32: flame detector microcontroller

33: external signal connection terminal 34: ceiling or mounting wall

35: Internal structure of the flame detector using the conventional ultraviolet sensor

36: Internal structure of the flame detector using the UV detection sensor of the present invention

37: Internal structure of the flame detector using the UV detection sensor of the present invention

Claims (1)

A transparent disk-shaped flame- transmitting flame detection window 19 of a material having a high ultraviolet transmittance for transmitting ultraviolet rays generated by an external flame into the sensor; Located at the bottom of the UV transmission flame detection window 19 is spaced apart, wound spirally from the inside outwards and straightened, and bent again in a direction perpendicular to the imaginary plane formed by the spiral, the lower disk housing ( A strand of positive lead wire 23 made of an electrical conductor material which extends and is exposed to the outside of the sensor through vertically intersecting 22) and exerts a positive voltage; A metal cathode plate 24 having a square shape, spaced apart from the lower end of the anode lead wire 23 and emitting photons when ultraviolet rays arrive; Welded in a direction parallel to the lower end of the negative electrode plate 24, the non-welded portion is bent again in the vertical direction of the lower end of the negative electrode plate and passes through the disk-shaped lower housing 22 vertically and extends to the outside of the sensor to be exposed. And a single negative lead wire 25 made of an electrical conductor material applying a negative voltage, It is spaced apart from the lower end of the positive lead line 23 and the negative lead line 25, parallel to the negative plate 24, a portion of the positive lead line 23 and a portion of the negative lead line 25 cross and pass vertically. The anode lead wire 23 and the cathode lead wire 25 are connected to each other by a disc-shaped lower housing 22, and (Cylindrical shape surrounding the side between the flame detection window 19 and the disc-shaped lower housing 22, the upper end of the cylinder is open, bonded and sealed with the flame detection window 19 and the adhesive, the lower end of the cylinder is also open Characterized in that it comprises a cylindrical side housing (21) bonded and sealed with a discotic lower housing (22), UV detection sensor for flame detection.

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