KR20080093767A - Diffusion-type gas sensor module using infrared rays - Google Patents

Abstract

A diffusion-type gas sensor module using infrared rays is provided to accurately measure the concentration of gas in air by forming an infrared ray transmission path for detecting variation in the concentration of gas. A diffusion-type gas sensor module using infrared rays comprises an infrared ray generator(9), an infrared ray transmission path, a sensor part(8), a housing(4), a sensor case(2), a first electric wire(81a), a second electric wire, a third wire(91), and an electric wire through-hole(51). The sensor part generates an output signal for the concentration of target gas in air by detecting infrared rays transmitted through the infrared ray transmission path. The housing has the infrared ray generator on its one end, the sensor part on its other end, and the infrared ray transmission path between its two ends. The sensor case coupled to the other end where the sensor part of the housing is installed has the sensor part. The first and second electric wires connect the sensor part to the infrared ray generator. The electric wire through-hole, wherein the third electric wire is passed, is formed inside the housing.

Description

Diffusion-type gas sensor module using infrared rays

1 is a perspective view of a diffused infrared gas sensor module 1 according to the present invention.

2 is a perspective view of the protective cover 3 of the diffused infrared gas sensor module 1 of the present invention in a separated state.

3 and 4 are exploded perspective views of the diffusion infrared gas sensor module 1 according to the present invention.

5 is an exploded perspective view of the waveguide part 60 of the diffusion infrared gas sensor module 1 of the present invention.

6 is an exploded perspective view of the diffusion infrared gas sensor module 1 of the present invention as viewed from the infrared generating unit 9 side.

7 is an exploded perspective view of the diffusion infrared gas sensor module 1 of the present invention as viewed from the sensor unit 8 side.

8 is a cross-sectional view of the diffusion infrared gas sensor module 1 of the present invention.

9 is a view for explaining the principle of operation of the diffuse infrared gas sensor of the present invention.

10 shows that the diffused infrared gas sensor module 1 according to the invention can be used in combination with the combustible gas detector 100.

11 is a circuit diagram of the sensor unit 8 of the diffusion infrared gas sensor module according to the present invention.

FIG. 12 is a circuit diagram of the negative power generator 840 converting the voltage to a voltage of -5V by using a voltage of + 5V in the part of FIG.

FIG. 13 is a circuit diagram of the first constant voltage converting unit 850 for converting the voltage to + 2.5V using the + 5V voltage at the part ⓐ in the circuit diagram of FIG.

FIG. 14 is a circuit diagram of the second constant voltage converting unit 860 for converting the voltage into a voltage of -2.5V using the voltage of -5V in the part ⓑ in the circuit diagram of FIG.

FIG. 15 is a circuit diagram of an infrared ray generating circuit 870 in the infrared ray generating portion 9 of the diffusion infrared gas sensor module according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: infrared gas sensor module 2: sensor case

2a: fastening part 2b: screw part

2c: male part 3: protective cover

3a: air inlet slit 3b: female threaded portion

4: housing 5a, 5b: side support rod

6: waveguide 6a: waveguide coupling socket

6b, 6c: Air hole 6d: Tightening screw

7: plug 7a: contact support

7b: male thread portion 7c: hexagonal wrench hole

8a: sensor circuit board 8b: sensor element

8c: Fastener 9: Infrared generator

9a: infrared lamp 9b: support plate

9c: fastener 21: wire entry hole

41: male thread portion 42: fastening rod

44: light receiver window 44a: second glass plate

44b: second molding 45: light emitting part window

45a: first glass plate 45b: first molding

46: fastening rod 47: female thread

51: wire passing hole 60: waveguide

81, 82: connector 81a, 82a: 1st, 2nd wire

85: reference sensor 85a: reference sensor filter

86: detection sensor 86a: detection sensor filter

87: temperature sensor 91: third wire

100: gas detector 101: detector cover

102: display unit 103: viewing window

104: sensor coupling tube 104a: fastening hole

105: cable passage 110: detector housing body

111: coupling hole 112: external ground terminal

120: cable 801,802: sensor power

811: reference signal amplifier 811a: first OP amplifier

812: detection signal amplifier 812a: second OP amplifier

814: AD converter 814a: signal conversion chip

820,821: reverse voltage prevention diode 823: winding resistance of third

824: Fourth winding resistance 825: Connector

826: FET 830: cable connector

840: negative power generation unit 840a: negative power generation chip

850,860: first and second constant voltage conversion unit 850a, 860a: first and second constant voltage diode

870: infrared ray generating circuit 871: winding resistance portion

871a: primary winding resistance 871b: secondary winding resistance

872: connector IRW: infrared wavelength

G: flammable gas

The present invention relates to a diffused infrared gas sensor module, and in particular, can be easily coupled modularly to gas detectors for measuring the concentrations of flammable gases and carbon dioxide using infrared light, which can measure gas concentration in the air very precisely. It relates to a diffusion infrared gas sensor module.

In modern society, fossil fuels such as petroleum, natural gas (LNG), and liquefied petroleum gas (LPG) are used as the main energy sources. It is widely used as a power source in industrial sites. Various combustible gases including natural gas and liquefied petroleum gas have a hydrocarbon-based molecular structure and are composed of a combination of carbon (C) and hydrogen (H), and methane, ethane, propane, butane gas, etc. These are included in the category of flammable gases.

In recent years, the number of factories and industrial sites dealing with flammable gas is increasing, and the risk of leakage due to the handling of flammable gas also increases. If a flammable gas leaks, it can cause enormous damages due to explosion and fire.In general, industrial sites that produce and manage flammable gas have gas detectors that can detect gas leakage at an early stage. If necessary, take prompt action.

However, the conventional flammable gas detector has a disadvantage in that accurate risk detection is difficult to be achieved because the precision of the concentration of the gas to be measured is not high. As the utilization of gas in our daily life and industrial sites increases, the risk of accidents caused by gas leakage increases in proportion to it, so the development of a gas sensor module capable of measuring gas concentration more accurately is urgently needed.

In addition, the conventional combustible gas detector is expensive, so that the machine itself costs millions of dollars, so that instead of replacing the entire expensive combustible gas detector, it makes the sensor module detachable from the gas detector and makes the sensor module more precise and By replacing them with reliable, high quality ones, it is advantageous to improve the performance of the entire gas detector. For this reason, there is a need for a new type of flammable gas sensor module capable of measuring the concentration of flammable gas and carbon dioxide more precisely at a much higher level of confidence than gas sensor modules used in conventional gas sensors.

The present invention, in order to solve the above problems, by using a combination of the existing gas detectors to measure the concentration of the combustible gas and carbon dioxide using infrared light in a high-precision diffusion to enable more accurate gas concentration measurement An object of the present invention is to provide an infrared gas sensor module.

In order to achieve the above object, the diffusion infrared gas sensor module provided by the present invention comprises: an infrared ray generator 9 for generating infrared rays; An infrared transmission path through which the gas to be measured flows in with the air and the infrared rays from the infrared generation unit 9 are transmitted and passed; A sensor unit 8 for detecting the infrared rays transmitted through the infrared transmission path and generating an output signal relating to the concentration of the measurement target gas present in the air; A housing (4) at one end of which the infrared generating unit (9) is installed, and at the other end of the sensor unit (8), and the infrared transmission path between the both ends; A sensor case (2) coupled to the other end of the housing (4) in which the sensor unit (8) is installed to embed the sensor unit (8); A first wire 81a and a second wire 82a connecting the sensor unit 8 and the gas detector; A third wire 91 connecting the sensor unit 8 and the infrared ray generating unit 9; And a wire passing hole 51 formed inside the housing 4 in parallel with the infrared transmission path, through which the third wire 91 passes.

First, the kind of gas detector is briefly demonstrated before detailed description regarding this invention.

Conventional gas detectors are divided into detectors for measuring flammable gases and detectors for toxic gases according to the type of gas to be measured, and the present application relates to a gas sensor module applied to a detector for measuring flammable gases. will be.

The gas detector is divided into a diffusion type and a suction type according to a method in which the gas to be measured reaches the sensor. Diffusion allows the gas to be measured to reach the sensor by natural air diffusion and is used when the sensor is installed adjacent to the gas leak zone. On the other hand, the suction type is a way to reach the sensor by sucking and transporting the gas into the pipe through an artificial method, it is mainly adopted when the sensor is installed far from the gas leakage area. The present application relates to a diffusion type gas sensor module that allows the flammable gases to reach the sensor naturally by the diffusion of air.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and effect of the diffusion type infrared gas sensor module according to the present invention.

1 is a perspective view of a diffusion infrared gas sensor module 1 according to the present invention, Figure 2 is a perspective view of the protective cover 3 is removed. 1 and 2, the diffusion infrared gas sensor module 1 of the present invention is a sensor case (2) having a fastening portion (2a) is formed to be coupled to the gas sensor 100 as described later in FIG. And a protective cover 3 screwed to the sensor case 2, and a plurality of air access slits 3a through which air enters and exit the surface of the protective cover 3.

A screw portion 2b is formed on the surface of the fastening portion 2a of the sensor case 2, and as shown in FIG. 10, a fastening hole 104a formed in the sensor coupling pipe 104 of the gas detector 100. The inner wall of the female screw portion corresponding to the screw portion (2b) is provided, it is possible to couple and detach the gas sensor module 1 of the present invention to the sensor coupling tube 104 of the gas sensor (100).

Referring to FIG. 2, the diffusion infrared gas sensor module 1 according to the present invention has a structure in which a housing 4 is coupled to a sensor case 2. Inside the housing 4, an infrared ray generator (9 in FIG. 3) for generating infrared rays, an infrared transmission path for guiding propagation of the infrared rays, and an output corresponding to the concentration of gas in the air by receiving the infrared rays A sensor section (8 in Fig. 3) for generating a signal is incorporated.

The infrared transmission paths will be described later with reference to FIGS. 5 to 8, the light emitting unit window 45 (see FIG. 6), the light receiving unit window 44 (see FIG. 7), and the light emitting unit window 45 and the light receiving unit window 44. ) Is composed of a waveguide portion 60 (FIG. 5), among which the waveguide portion 60 is formed in a tubular shape and coupled with the waveguide 6 and the waveguide 6 having air holes 6b formed on the surface thereof. It consists of a waveguide coupling socket 6a.

As shown in Figure 2, one side of the sensor case (2) is provided with a fastening portion (2a) for coupling / separation with the gas detector (100 in Figure 10), the protective cover (3) on the opposite side The male screw portion 2c is formed so that the screw can be coupled or separated. In response to the male screw portion 2c, a female screw portion 3b is formed on the inner wall surface of one end of the protective cover 3.

The waveguide 6 and the waveguide coupling socket 6a are positioned in the middle portion of the housing 4, and side support rods 5a and 5b are provided on both sides thereof. The side support rods 5a and 5b are integrally formed with the housing 4, and the waveguide 6 and the waveguide coupling socket 6a are detachably installed in spaces spaced therebetween.

In FIG. 2, an infrared ray generator is embedded in the right end of the housing 4, and a stopper 7 blocks a space in which the infrared ray generator is embedded.

3 and 4 are exploded perspective views of the diffusion infrared gas sensor module 1 according to the present invention. 3 and 4, an infrared ray generating unit 9 and a sensor unit 8 are embedded at both ends of the housing 4, respectively. The infrared generating unit 9 generates infrared rays by the infrared lamp 9a and sends them to the waveguide 6 and the waveguide coupling socket 6a, and the sensor unit 8 has a sensor element 8b connected to the waveguide ( 6) and detects the level of the infrared rays passing through the waveguide coupling socket 6a to generate an output signal corresponding to the concentration of the target gas (flammable gases and carbon dioxide) in the air.

The sensor unit 8 includes a sensor circuit board 8a having a circuit formed on a printed circuit board and a sensor element 8b provided on the sensor circuit board 8a. The sensor element 8b includes a reference sensor 85 (See FIG. 9) and the detection sensor 86 (see FIG. 9) are built together and manufactured integrally.

Of the two sensors embedded in the sensor element 8b, the reference sensor (reference numeral 85 in FIG. 9) detects only infrared rays of a first wavelength band having a property of being transmitted without being affected by the concentrations of flammable gas and carbon dioxide in air. A reference signal of a constant level is always generated, and a detection sensor (reference numeral 86 in FIG. 9) detects only the infrared rays of the second wavelength band having a property of being attenuated according to the concentrations of flammable gas and carbon dioxide present in the air and thus the gas concentration. Generates an output signal corresponding to

As such, the reference sensor and the detection sensor can selectively accept only wavelengths of a specific band because filters are provided to selectively pass only wavelengths of a specific band in front of the reference sensor and the detection sensor. to be. That is, the reference sensor filter 85a installed in front of the reference sensor 85 passes only infrared rays of the first wavelength band, and the detection sensor filter 86a installed in front of the detection sensor 86 has a second wavelength band. Only infrared light passes through.

In FIG. 4, a space in which the sensor unit 8 is mounted is provided at an end portion of the housing 4 in the sensor case 2. In FIG. 3, an end portion of the housing 4 in the infrared generator 9 is provided at the end portion of the housing 4. The space in which the infrared ray generating unit 9 is mounted is provided. Referring to FIG. 4, fastening holes 8c are formed at the periphery of the sensor circuit board 8a of the sensor unit 8, and fastening bars 42 protruding from the left end surface of the housing 4. ) Is intended to be By this coupling structure, the sensor unit 8 is stably installed in the space at the left end of the housing 4 so that it does not shake even by external vibration or the like.

The sensor circuit board 8a of the sensor unit 8 is connected to the gas detector 100 (see FIG. 10) by the first wire 81a and the second wire 82a. A first connector 81 is formed at an end of the first wire 81, and a second connector 82 is formed at an end of the second wire 82a so that these connectors 81 and 82 are formed. The sensor unit 8 is connected to the gas detector by being connected to each other. The sensor unit receives power from a gas detector through the first and second wires 81a and 82a and transmits output signals (reference signal and detection signal) according to infrared detection to the gas detector. The first and second wires 81a and 82a may be combined into a single wire, but for convenience of the operation of combining or separating the gas sensor module 1 and the gas detector of the present invention, as shown in FIGS. It is desirable to configure the two wires and to be able to easily connect and disconnect them by the connectors 81 and 82.

In Fig. 3, the female screw portion 2d formed on the inner surface of the right end of the sensor case 2 corresponds to the male screw portion 41 formed on the outer surface of the left end of the housing 4, and these female screws The sensor case 2 and the housing 4 are coupled to and separated from each other by coupling and detaching the portion 2d and the male screw portion 41.

The sensor unit 8 and the infrared ray generating unit 9 are connected by a third wire 91, and the third wire 91 is one of the two side support rods 5a and 5b of the housing 4. It extends to the infrared ray generating part 9 along the wire entry hole 51 (refer FIG. 7 and FIG. 8) formed along the longitudinal direction in either side support rod.

On the other hand, the infrared generating unit 9 is composed of an infrared lamp 9a which generates infrared wavelengths by being heated by the supply of electricity and a supporting plate 9b provided with the infrared lamp 9. The third wire 91 is connected to the support plate 9b. The stopper 7 is screwed to the right end of the housing 4 to be supported by pressing the infrared generating unit 9.

4 shows a state in which the waveguide 6 and the waveguide coupling socket 6a are separated from the housing 4. As described above, when the length of the fastening screw portion 6d is inserted into the waveguide coupling socket 6a by rotating the waveguide 6 increases the total length of the waveguide 6 and the waveguide coupling socket 6a. Since it can be reduced, the waveguide 6 and the waveguide coupling socket 6a can be inserted into or removed from the housing 4.

As shown in Figs. 4 and 6, the light emitting part window 45 is provided on the side where the infrared generating part 9 of the housing 4 is located. The light emitting unit window 45 fixes the first glass plate 45a and the first glass plate 45a to the housing 4 to transmit infrared rays generated from the infrared generating unit 9 into the waveguide 6. It is composed of a first molding 45b. The first glass plate 45a is made of a kind of opaque glass to effectively pass only infrared rays. Sanding the surface of the quartz glass with coarse particles such as sand is used to make the first glass plate 45a opaque glass. By the process of forming a myriad of fine scratches on the surface.

Referring to FIG. 6, the infrared lamp 9a of the infrared ray generating unit 9 is located immediately adjacent to the light emitting unit window 45 installed in the housing 4. Fastening holes 9c are formed in the support plate 9b of the infrared ray generating unit 9 so as to fit with the fastening rods 46 protruding in the space in the housing 4. On the other hand, the male screw portion 7b formed on the outer side of the cap 7 corresponds to the female screw portion 47 formed on the inner side of the housing 4, so that the cap 7 is screwed on the end of the housing 4. Can be combined. In addition, a hexagon wrench hole 7c is formed on the outer surface of the stopper 7 for the convenience of fastening and detaching.

5 is an exploded perspective view of the waveguide part 60 of the diffusion infrared gas sensor module 1 of the present invention.

The waveguide portion 60 constituting a part of the infrared propagation path is composed of a waveguide 6 made of metal and a waveguide coupling socket 6a that can be coupled to or separated from the waveguide 6. The waveguide 6 and the waveguide coupling socket 6a are manufactured in a pipe shape having a small diameter, and a plurality of air holes 6b and 6c are formed on the surface thereof, so that the gas sensor module of the present invention ( Outside air where 1) is placed can enter the waveguide 6 and the waveguide coupling socket 6a. A screw portion 6d is formed at one end of the waveguide 6, and a female screw portion (not shown) corresponding to the screw portion 6d is formed at a part of the inner wall surface of the waveguide coupling socket 6a. The waveguide (6d) of the waveguide (6) is more out of the waveguide coupling socket (6a) while the waveguide (6) and the waveguide coupling socket (6a) is fastened into the housing (4). When 6) is held by hand, the entire length of the waveguide 6 and the waveguide coupling socket 6a is lengthened to fit tightly in the housing 4. On the other hand, when the threaded portion 6d of the waveguide 6 is rotated while holding the waveguide 6 so as to enter more into the waveguide coupling socket 6a, the entirety of the waveguide 6 and the waveguide coupling socket 6a As the length becomes shorter they are separated from the housing 4 (see FIGS. 4 and 5).

6 is an exploded perspective view of the diffusion infrared gas sensor module 1 of the present invention as viewed from the infrared generating unit 9 side. Referring to FIG. 6, a space on which an infrared ray generator 9 is seated is provided at an end portion of the gas sensor module 1 of the present invention at an infrared ray generator 9, and an infrared ray generator 9 at the center thereof. A light emitting part window 45 is provided through which infrared rays from the light pass to enter the waveguide 6. The light emitting part window 45 has a structure in which a first glass plate 45a is inserted into a cylindrical first molding 45b. The first glass plate 45a is made of a kind of opaque glass to effectively pass only infrared rays. . The first glass plate 45a is made of quartz glass, and the surface of the first glass plate 45a is sanded with coarse particles such as sand to form a myriad of fine scratches on the surface to make opaque glass.

The support plate 9b of the infrared ray generating unit 9 is securely installed in the housing 4 by coupling fastening holes 9c formed at its periphery with the fastening rods 46 of the housing 4. Then, the plug 7 is screwed into the female screw portion 47 formed on the inner wall of the end of the housing 4 so that the infrared ray generating portion 9 of the housing 4 is closed by the plug 7. It is mounted inside without shaking.

7 is an exploded perspective view of the diffusion infrared gas sensor module 1 of the present invention as viewed from the sensor unit 8 side. As shown in FIG. 7, the waveguide 6 and the waveguide coupling socket 6a exit from the infrared ray generator 9 at the end of the housing 4 positioned opposite to the place where the infrared ray generator 9 is seated. The sensor part 8 which receives the infrared ray which passed through and detects gas concentration is provided. The light receiving portion window 44 is installed at the central portion of the housing 4 in contact with the waveguide coupling socket 6a. The light-receiving part window 44 corresponds to the light-emitting part window 45 described in FIG. 6, where infrared light passing through the waveguide 6 passes to enter the sensor part 8. The light receiving part window 44 is composed of a second glass plate 44a and second moldings 44b and 44c for supporting the second glass plate 44a on the housing 4.

On the other hand, it is preferable that the second glass plate 44a of the light receiving unit window 44 is made of transparent glass. Whereas the first glass plate 45a of the light emitting part window 45 shown in FIG. 6 is made of opaque glass, the second glass plate 44a of the light receiving part window 44 is made of transparent glass. This is because the light entering the unit 60 is only infrared rays, and thus, surface treatment for receiving only infrared rays into the sensor unit 8 is not necessary.

The light emitting part window 45 and the light receiving part window 44 shown in Figs. 6 and 7 are both manufactured in an explosion-proof structure in which the housing is completely sealed off from the outside air. If there is a flammable gas, if the spark occurs by electrical operation in the gas sensor module 1 or the gas detector of the present invention, there is a great risk of a fire, so the internal circuit portion of the gas sensor or gas sensor module is It must be completely isolated from the environment. For this reason, moldings 45b, 44b and 44c which hermetically support these first and second glass plates are used in installing the first and second glass plates 45a and 44a in the housing 4. .

8 is a cross-sectional view of the diffusion infrared gas sensor module 1 of the present invention. Referring to FIG. 8, the second wire 82a, which is connected to the gas sensor to which the gas sensor module 1 of the present invention is coupled, is connected to the first wire 81a, and the first wire 81a is a sensor unit ( 8 is welded to the sensor circuit board 8a. The sensor circuit board 8a and the support plate 9b of the infrared ray generating unit 9 are connected by a third wire 91. The infrared lamp 9a of the infrared ray generating unit 9 preferably does not generate visible light but heats red when electricity is supplied to generate infrared light. It is preferable that the infrared lamp 9a be turned on and off at regular intervals by a switching means such as a field effect transistor (FET) rather than being kept on continuously.

The infrared wavelength generated by the infrared lamp 9a passes through the first glass plate 45a of the light emitting part window 45 and then enters the waveguide 6, followed by the second glass plate 44a of the light receiving part window 44. It passes through the sensor element 8b of the sensor part 8 through it.

In the sensor element 8b, there is a reference sensor and a detection sensor, and outputs an output signal changed in accordance with the gas concentration in the air existing in the waveguide 6.

As shown in Fig. 8, side support rods 5a and 5b are present in the center portion of the housing in parallel with the waveguide 6 and the waveguide coupling socket 6a, and among the side support rods 5a and 5b. One of the wire passing holes 51 through which the third wire 91 can pass is provided. In FIG. 8, the wire through hole 51 is formed in the side support bar 5a for convenience.

9 is a view for explaining the principle of measuring the concentration of the flammable gas and carbon dioxide by using the infrared infrared diffusion gas sensor of the present invention.

Infrared rays are radio waves that are a kind of energy waves and have a wavelength in the range of 0.76 to 1000 µm. According to the wavelength, 0.76 to 1.5 µm is called near-infrared and 1.5 to 5.6 µm is called mid-infrared, and 5.6 to 1000 µm is called far-infrared. .

The wavelength band used for gas detection in the gas sensor module of the present invention is a mid-infrared band of 3-5 μm, and the concentration of gas using gas molecules having a property of selectively absorbing energy corresponding to unique vibration energy levels. Can be measured.

In the present invention, the concentration of the combustible gas or the like is measured using the principle of non-dispersive infrared (NDIR) which allows light to pass through without being dispersed. This method is a method of measuring the gas concentration by converting the infrared absorption rate of the measurement gas into current or voltage.

The wavelength band of infrared rays absorbed by hydrocarbon-based flammable gases (LP, LENG, etc.) is 3.3 µm, the absorption wavelength band of carbon dioxide is 4.26 µm, and the absorption wavelength band of carbon monoxide is 4.6 µm.

As such, only components belonging to a predetermined wavelength band of infrared rays are selectively absorbed by the flammable gas or carbon dioxide, and thus the infrared rays pass through the air where the combustible gas or carbon dioxide is present. By measuring how much the corresponding infrared component is absorbed in the gas, it is possible to measure the concentration of the combustible gas and carbon dioxide present in the air. That is, the higher the concentration of flammable gas or carbon dioxide in the air, the lower the intensity of infrared rays corresponding to the wavelength band (3.3 μm, 4.26 μm, 4.6 μm), while the concentration of the flammable gas or carbon dioxide in the air The lower the intensity of the infrared rays in the wavelength band is greater.

As described with reference to Fig. 4, the sensor element 8b for generating an output signal according to the gas concentration is composed of two sensors, namely, a reference sensor portion and a detection sensor portion.

Among these, the reference sensor unit generates a reference signal of the same level at all times regardless of the concentration of the measurement target gas present in the air, and the detection sensor unit generates a detection signal changed corresponding to the concentration of the measurement target gas present in the air. Therefore, knowing the difference between the reference signal and the detection signal, it is possible to determine the concentration of the gas present in the air. However, even when the gas concentration is the same, the difference value between the reference signal and the detection signal can be changed as the temperature of the air is changed, so it is necessary to correct the error according to the change of the temperature. To this end, the sensor unit 8 is provided with a temperature sensor 87 for measuring the current air temperature.

Referring to FIG. 9, the reference sensor unit passes only infrared rays of a first wavelength band (for example, 4.0 μm) having a property of being transmitted without being influenced by the concentration of the gas to be measured present in the waveguide unit 60. And a reference sensor 85 that detects the intensity of infrared rays passing through the filter 85a and the reference sensor filter 85a and generates a reference signal.

In addition, the detection sensor unit passes only infrared rays of a second wavelength band (for example, 3.3 μm in the case of flammable gas) having a property of being attenuated (absorbed) corresponding to the concentration of the gas to be measured in the waveguide unit 60. A detection sensor filter 86a and a detection sensor 86 that detects the intensity of the infrared light passing through the detection sensor filter 86a and generates a detection signal.

In FIG. 9, reference numeral IRW denotes an infrared wavelength generated from the infrared lamp 9a and passed through the waveguide part 60, and G denotes a flammable gas.

In Fig. 9, the reference sensor filter 85a uses a filter that passes only a wavelength of 4.0 mu m, and the detection sensor filter 86a has a wavelength of 3.3 mu m, for example, for detecting a hydrocarbon-based flammable gas. A filter that passes only a bay is used, and a filter that passes only a wavelength of 4.6 µm is used for detecting carbon monoxide, and a filter that passes only a wavelength of 4.26 µm is used for detecting carbon dioxide.

Therefore, regardless of the presence of flammable gas, carbon monoxide, and carbon dioxide, all of the infrared light generated from the infrared lamp 9a belonging to the wavelength band of 4.0 μm passes through the reference sensor filter 85a to receive the reference sensor 85. The reference sensor 85 always generates an output signal of a constant level.

On the other hand, the detection sensor 86 has a different magnitude of the output signal depending on the concentration of the gas to be detected. That is, in the case of a sensor module for detecting a hydrocarbon-based flammable gas (G), a filter that passes only a wavelength of 3.3 μm is used for the detection sensor filter 86a. When the flammable gas does not exist, the reference sensor 85 is used. And the output signal level of the detection sensor 86 are all the same, but if there is a flammable gas, infrared components having a wavelength of 3.3 mu m are absorbed by the flammable gas G in the waveguide part 60, and the detection sensor 86 Since the light is received less, the level of the output signal is smaller.

10 shows that the diffused infrared gas sensor module 1 according to the invention can be used in combination with the combustible gas detector 100.

Referring to FIG. 10, the gas sensor module 1 according to the present invention may be coupled to the sensor coupling pipe 104 of the gas sensor 1. The gas detector 1 is composed of a cylindrical housing body 110 and a detector cover 101 coupled to the upper portion of the housing body 110 by screwing. One or two cable through pipes 120 are formed on the side of the housing body 110, and the cable through pipes 120 are supplied with power from the outside and transmit an output signal of a sensor to a control panel (not shown). Wire cable 120 for connecting is connected.

Preferably, the housing body 110 and the detector cover 101 are all made of aluminum alloy, and are manufactured in an explosion-proof type so that components such as electronic circuits and sensors therein are completely isolated from the outside. Since the flammable gas detector 100 is installed in a place where a flammable gas may be leaked, even if any one of the electronic circuits or wiring inside the housing burns out due to a short circuit, overheating or other accidents, the combustion is not carried out inside the housing. It should not be allowed to leak and the combustion flames will leak out of the housing and cause an explosion or fire by combustible gas. Thus, the housing body 110 and the detector cover 104 are made of a refractory material that can withstand the risk of explosion of flammable gas.

A transparent viewing window 103 is installed at the center of the detector cover 101 so that the user can see the contents displayed on the display unit 102 therein.

Since the gas detector 1 is installed in various places of the industrial site where there is a risk of gas leakage, it needs to be fixed at a specific position. To this end, coupling holes 111 for coupling bolts and the like are formed below the housing body 110. Then, in order to prevent electric shock, an external ground terminal 112 is formed on a part of the housing body 110, and the ground is connected by connecting a wire to the outer ground terminal 112 and connecting a conductor such as a pole to the ground. .

11 is a circuit diagram of the sensor unit 8 of the diffusion infrared gas sensor module according to the present invention. Referring to FIG. 11, the sensor unit 8 includes a sensor element 8b installed together with the reference sensor unit and a detection sensor unit to output a reference signal and a detection signal, and a reference signal output from the sensor element 8b. Of the reference signal amplifier 811 for amplifying the signal to a predetermined level, the detection signal amplifier 812 for amplifying the detection signal output from the sensor element 8b to a predetermined level, and the reference signal amplifier 811 of the reference signal amplifier 811. An A / D converter 814 for converting an output signal, an output signal of the detection signal amplifier 812, and an output signal of the temperature sensor 7 into digital signals and transmitting the digital signal to the gas detector, and the infrared generation And switch means 826 for interrupting or applying electricity supplied to the unit 9.

The sensor element 8b operates with a power supply of ± 2.5 V, and outputs an output signal (reference signal) of the reference sensor and an output signal (detection signal) of the detection sensor, respectively, to the reference signal amplifier 811 and the detection signal amplifier ( 812). A first OP amplifier 811a is included in the reference signal amplifier 811, and a second OP amplifier 812a is included in the detection signal amplifier 812. On the other hand, a temperature sensor 87 for sensing the temperature is provided separately.

The reference signal and the detection signal amplified by the reference signal amplifier 811 and the detection signal amplifier 812, respectively, and the output signal from the temperature sensor 87 are all digital signals by the A / D converter 814. Changes to Subsequently, the digitized reference signal, the detection signal, and the temperature detection signal are transmitted to the central processing unit (CPU) of the gas detector through the connector 830.

On the other hand, the connector 830 and the wire cables connected thereto serve as a passage for transmitting the output signals of the sensor unit to the gas detector and at the same time serves as a passage for supplying power from the gas detector to the sensor unit. The power supplied from the sense sensing is basically + 5V, and reverse voltage preventing diodes 820 and 821 are installed to prevent reverse voltage from being applied. In addition, a connector 845 is installed in a passage for transmitting power from the sensor unit to the infrared generating unit, and a third winding resistor 823 and a fourth winding resistor 824 are disposed between the sensor unit and the connector 845. Formed.

In FIG. 11, reference numeral 826 denotes a field effect transistor (FET) for supplying or cutting off power transmitted to the connector 845, and the field effect transistor 826 turns on and off an infrared lamp at a predetermined time interval. It happens repeatedly.

FIG. 12 is a circuit diagram of the negative power generator 840 converting the voltage to a voltage of -5V by using a voltage of + 5V in the part of FIG. In FIG. 11, a part indicated by ⓐ indicates a + 5V power transmitted from gas detection, and the negative power generator 840 of FIG. 12 uses the + 5V power of the ⓐ part using a negative power generation chip 840a. It converts into a -5V power supply and transfers this converted -5V negative power supply to the part indicated by ⓑ of FIG.

FIG. 13 is a circuit diagram of the first constant voltage converter 850 for converting the voltage to + 2.5V using the voltage of + 5V at the part ⓐ in the circuit diagram of FIG. When a voltage of +5 V in the portion indicated by ⓐ in FIG. 11 enters the first constant voltage diode 850a of the first constant voltage converting unit 850, the constant voltage down to +2.5 V is output therefrom. The downed + 2.5V constant voltage is transferred to the part indicated by ⓒ in FIG.

FIG. 14 is a circuit diagram of a second constant voltage converting unit 860 converting the voltage into a voltage of -2.5V using the voltage of -5V in the part ⓑ in the circuit diagram of FIG. In FIG. 12, the -5V power source converted to the negative power source is output by being down to a voltage of -2.5V by the second constant voltage diode 860a of the second constant voltage conversion unit 860 of FIG. This down -2.5V constant voltage is transferred to the portion indicated by ⓓ in the circuit diagram of FIG.

15 is a circuit diagram of an infrared ray generating circuit 870 in the infrared ray generating section 9 of the diffusion type infrared gas sensor module according to the present invention. The circuit of the infrared ray generating unit 9 includes a connector CN1 connected to the third wire 91, an infrared lamp 9a connected by a wire to the connector CN1, the connector CN1 and the infrared lamp ( It consists of a 1st winding resistance 871a and a 2nd winding resistance 871b provided on the circuit which connects 9a).

Diffuse infrared gas sensor module according to the present invention has a relatively long infrared transmission path (that is, a waveguide portion) compared to the conventional gas sensor module can detect a minute change in the gas concentration in the air, the more precise gas concentration of Measurement is possible.

In addition, the gas sensor module of the present invention, except for the waveguide portion through which air is introduced, has a flame-proof structure in which the entire housing including the sensor, the infrared lamp, and the circuits is completely sealed off from the outside, whereby flammable gas exists. When used in the environment, it has the effect of fundamentally preventing the risk of explosion and combustion.

And, since the gas sensor module of the present invention has a structure that can be easily modularized to existing flammable gas detectors, the gas sensor module mounted on the existing gas detector without having to replace the existing flammable gas detectors themselves. By removing the bay and mounting the gas sensor module of the present invention, there is an advantage to achieve a much improved and safe gas detection performance.

Claims (13)

In the gas sensor module is applied to a gas detector for measuring the concentration of at least one of the gases including the combustible gases and carbon dioxide (CO ₂ ), An infrared ray generator 9 for generating infrared rays; An infrared transmission path through which the gas to be measured flows in with the air and the infrared rays from the infrared generation unit 9 are transmitted and passed; A sensor unit 8 for detecting the infrared rays transmitted through the infrared transmission path and generating an output signal relating to the concentration of the measurement target gas present in the air; A housing (4) at one end of which the infrared generating unit (9) is installed, and at the other end of the sensor unit (8), and the infrared transmission path between the both ends; A sensor case (2) coupled to the other end of the housing (4) in which the sensor unit (8) is installed to embed the sensor unit (8); First and second wires 82a and 82a connecting the sensor unit 8 and the gas detector; A third wire 91 connecting the sensor unit 8 and the infrared ray generating unit 9; And And a wire passing hole (51) formed in the housing (4) in parallel with the infrared transmission path for the third wire (91) to pass therethrough. The method of claim 1, wherein the infrared ray generating unit 9, An infrared lamp 9a that is heated by electricity received from the sensor unit 8 and emits infrared rays; And And a support plate (9b) having the infrared lamp (9a) installed therein. The method of claim 1, wherein the sensor unit 8, A reference sensor unit which always generates an output signal having the same level regardless of the concentration of the measurement target gas present in the air; A detection sensor unit generating an output signal changed according to the concentration of the measurement target gas present in the air; And And a temperature sensor 87 for detecting an air temperature and generating an output signal. The reference sensor unit includes a reference sensor filter 85a and the reference sensor filter 85a that pass only infrared rays of a first wavelength band having a property of being transmitted without being affected by the concentration of a gas to be measured on the infrared transmission path. A reference sensor 85 which detects the intensity of the infrared rays passing through and generates a reference signal, The detection sensor unit passes through the detection sensor filter 86a and the detection sensor filter 86a that pass only infrared rays of a second wavelength band having a property of being attenuated corresponding to the concentration of the gas to be measured on the infrared transmission path. Diffuse infrared gas sensor module, characterized in that it comprises a detection sensor 86 for detecting the intensity of one infrared ray to generate a detection signal. The method of claim 1, wherein the infrared transmission path, A light emitting unit window 45 which is adjacent to the infrared generating unit 9 and passes infrared rays generated by the infrared generating unit 9; A waveguide part 60 having one end connected to the light emitting part window 45 and passing infrared rays, and having a plurality of air holes 6b and 6c formed therein and allowing air to be diffused; And One side is connected to the other end of the waveguide portion (60) and the other side is a light-receiving unit window (44) installed adjacent to the sensor unit (8); diffused infrared gas sensor module comprising a. The light emitting part window 45 of claim 4, wherein the light emitting part window 45 is fixed to the inside of the housing 4 adjacent to the infrared ray generating part 9, and the first molding 45b. It is supported by and comprises a first glass plate 45a through which the infrared rays emitted from the infrared generating unit 9 passes, The light receiving part window 44 is supported by the second molding 44b fixed to the inside of the housing 4 adjacent to the sensor part 8, and the second molding 44b, and the waveguide part ( 60. A diffused infrared gas sensor module comprising a second glass plate (44a) through which infrared light passes through. 6. The diffusion infrared gas sensor module according to claim 5, wherein the first glass plate (45a) is an opaque glass plate made of an opaque glass by polishing the surface thereof. The method of claim 5, wherein the waveguide portion 60, A waveguide 6 having a form of a pipe, one end of which is coupled to the molding of the light emitting part window 45, and a fastening screw part 6d is formed at the other end thereof, and the air holes 6b are formed on a surface thereof. ; And A female thread portion coupled to the fastening screw portion 6d of the waveguide 6 is formed at an inner wall of one end thereof, and a waveguide coupling socket 6a having the other end coupled to a molding of the light receiving portion window 44. Diffuse infrared gas sensor module, characterized in that can be detachably coupled to the housing (4). The diffused infrared gas sensor module according to claim 1, wherein the sensor case (2) has a fastening portion (2a) formed with a screw portion (2b) and can be detachably coupled to the gas detector. The method of claim 1, further comprising a protective cover (3) surrounding the housing (4), The protective cover 3 has a plurality of air access slits 3a formed on the surface thereof and female threads 3b formed on the inner side of one end thereof. The sensor case (2) is further provided with a male screw portion (2c) on the opposite side of the position where the fastening portion (2a) is provided, Diffuse infrared gas sensor module, characterized in that the protective cover (3) is coupled to the sensor case (2) by the combination of the female screw portion (3b) and the male screw portion (2c). The method of claim 3, wherein the sensor unit 8, A sensor element 8b installed together with the reference sensor unit and the detection sensor unit to output a reference signal and a detection signal; A reference signal amplifier 811 for amplifying the reference signal output from the sensor element 8b to a predetermined level; A detection signal amplifier 812 for amplifying the detection signal output from the sensor element 8b to a predetermined level; A / D for converting the output signal of the reference signal amplifier 811, the output signal of the detection signal amplifier 812, and the output signal of the temperature sensor 7 into digital signals and transmitting the digital signals to the gas detector, respectively. Converter 814; And And a switch means (826) for blocking or applying electricity supplied to the infrared ray generator (9). 11. The diffusion infrared gas sensor module according to claim 10, wherein the switch means (826) uses a field effect transistor (FET). The method of claim 10, wherein the sensor unit 8 receives the power of 5V from the gas detector, A negative power generator 840 for converting the power of 5V into a power of -5V; A first constant voltage converter 850 converting the 5V power supplied from the gas detector into the 2.5V power; And And a second constant voltage converter 860 for converting the -5V power output from the negative power generator 840 into a -2.5V power source. The sensor element (8b) is a diffusion type infrared gas sensor module, characterized in that the operation by the power supply of ± 5V output from the first constant voltage converter 850 and the second constant voltage converter 860. The method of claim 2, wherein the infrared ray generating unit 9, A connector CN1 connected to the third wire 91; And And a first winding resistor (871a) and a second winding resistor (871b) installed on a circuit connecting the connector (CN1) and the infrared lamp (9a).

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