JP2009128111A - Light receiving unit and concentration measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact concentration measuring apparatus accurately measuring the concentration of a plurality of types of gases. <P>SOLUTION: The concentration measuring apparatus includes a gas sample chamber. In the gas sample chamber, a light source for radiating infrared rays is arranged at one end part in a cell filled with an atmosphere, and a light receiving unit 8 for receiving infrared rays is arranged at the other end part. The light receiving unit 8 includes: a unit body 11 in which an opening part 11a is formed on the side opposed to the light source; a dividing member 12 extended in a direction from the one end part to the other end part for dividing an internal space of the unit body 11 into a plurality of spaces 10a and 10b; a plurality of filters 15a and 15b which are each arranged on the side of an opening part 11a of the spaces 10a and 10b and which transmit infrared rays having different wavelengths; and a plurality of sensors 14a and 14b each arranged in the spaces 10a and 10b for receiving infrared rays transmitted through the filters 15a and 15b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light receiving unit used in a concentration measuring device that measures the concentration of a predetermined gas such as carbon dioxide, water vapor, and carbon monoxide contained in an atmosphere, and a concentration measuring device having the light receiving unit.

  For example, various gas sample chambers have conventionally been used for concentration measuring devices that measure the concentration of a predetermined gas such as carbon dioxide, water vapor, or carbon monoxide. A conventional gas sample chamber has a cylindrical cell filled with an atmosphere, a light source that emits infrared light disposed at one end of the cell, and a light receiver disposed at the other end of the cell. (For example, refer to Patent Document 1).

  The light receiver includes an infrared sensor and a filter that is disposed between the infrared sensor and the light source and transmits only infrared light having a predetermined wavelength. The infrared wavelength that passes through the filter is determined by the measured concentration range for the gas to be measured. That is, the infrared wavelength that passes through the filter depends on the measurement concentration range of the measurement target gas, such as the infrared wavelength that is most easily attenuated if the measurement range of the measurement target gas is on the order of 0 ppm to several thousand ppm. Appropriately selected.

  The above-described conventional gas sample chamber, that is, the concentration measuring apparatus measures the concentration of the gas to be measured in the atmosphere by measuring the intensity of infrared rays from the light source received by the infrared sensor through the filter. .

  Further, the conventional concentration measuring apparatus described above has provided a plurality of gas sample chambers having the above-described configuration when there are a plurality of types of gases to be measured. For this reason, the concentration measuring device tends to increase in size.

Therefore, Patent Document 2 has devised a concentration measuring device that is miniaturized by providing a plurality of light receiving sections in one cell. However, since this concentration measuring device has a configuration in which a plurality of light receivers are simply provided in one cell, the infrared light transmitted through the filter of one light receiver is received by the infrared sensor of the other light receiver. There is a possibility that concentration measurement with high accuracy cannot be performed.
Japanese Patent Laid-Open No. 05-054242 JP 2003-172700 A

  Accordingly, an object of the present invention is to provide a light receiving unit capable of simultaneously measuring the concentrations of a plurality of types of gases to be measured in the atmosphere with high accuracy and miniaturizing a mounted device, and a concentration measurement having the light receiving unit. To provide an apparatus.

  In order to achieve the above object, the invention described in claim 1 is a light receiving device disposed at the other end portion of the cell for receiving light from a light source disposed at one end portion of the cell filled with an atmosphere. A box-like box-shaped member having an opening formed on the side facing the light source, and extending in a direction from the one end to the other end, and an internal space of the box-shaped member A plurality of filters each having a splitting member that divides into a plurality of spaces, a plurality of filters that are respectively arranged on the opening side of the plurality of spaces, and that transmit only light having a predetermined wavelength and that transmit light; A light receiving unit comprising a plurality of sensors arranged in each of a plurality of spaces and receiving light transmitted through the filter.

  The invention described in claim 2 is the invention described in claim 1, wherein the dividing member divides the space in the unit main body into a plurality of spaces having different volumes. It is. For this reason, a sensor arranged in a space with a large volume can receive more light from a light source than a sensor arranged in a space with a small volume. It can be measured with higher sensitivity.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the light receiving surfaces of the plurality of sensors are inclined with respect to a direction from the one end portion toward the other end portion. It is characterized by being arranged.

  The invention described in claim 4 is a gas sample chamber in which a light source is arranged at one end in a cell and a light receiving unit for receiving light from the light source is arranged at the other end, and the light receiving unit receives the light. A concentration measuring device having a concentration calculation unit that calculates a concentration of a predetermined gas in the gas sample chamber based on the intensity of light from a light source. Among these, the concentration measuring device is characterized by having the light receiving unit described in item 1.

  According to the first aspect of the present invention, a light receiving unit disposed at the other end of the cell that receives light from a light source disposed at one end of the cell filled with the atmosphere faces the light source. A box-shaped box-shaped member having an opening formed on the side, a split member that extends along the direction from the one end to the other end, and divides the internal space of the box-shaped member into a plurality of spaces; A plurality of filters each disposed on the opening side of the plurality of spaces and transmitting only light of a predetermined wavelength and having different wavelengths of light to be transmitted; and each of the plurality of spaces, Since it has multiple sensors that receive the light that has passed through, it can simultaneously measure the concentration of multiple types of gases to be measured in the atmosphere with high accuracy and downsize the mounted device Light receiving unit It can be.

  In the present invention according to claim 2, since the dividing member divides the space in the unit main body into a plurality of spaces having different volumes, the concentrations of a plurality of types of gases to be measured in the atmosphere. Measurement can be performed at the same time with high accuracy.

  According to the third aspect of the present invention, since the light receiving surfaces of the plurality of sensors are inclined with respect to the direction from the one end to the other end, the distance from the light source to each sensor Since each sensor can receive a large amount of light before the light from the light source diffuses, the concentration of each gas can be measured with high accuracy.

  Since this invention of Claim 4 has the light-receiving unit of Claim 1 among Claims 1-3, it is small and can measure the density | concentration of multiple types of gas used as the measuring object in atmosphere. At the same time, it is possible to provide a concentration measuring device that can be accurately performed.

(First embodiment)
Hereinafter, a concentration measuring apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 2, the concentration measuring apparatus 1 includes a gas sample chamber 2 filled with an atmosphere containing a gas whose concentration is to be measured, a control circuit unit 3, a light receiving circuit unit 4, and a concentration calculating unit. And a microcomputer 5 (hereinafter referred to as μcom).

  As shown in FIG. 1, the gas sample chamber 2 includes a cell 6, a light source 7, and a light receiving unit 8. The cell 6 is formed in a cylindrical shape. In the illustrated example, the cell 6 is formed in a square cylinder shape. The cell 6 is provided with an inlet 9a for introducing the atmosphere into the cell 6 and an outlet 9b for guiding the atmosphere within the cell 6 to the outside. That is, the gas sample chamber 2 has an inlet 9a and an outlet 9b. These inlet 9a and outlet 9b penetrate the outer wall 6a of the cell 6 and make the gas in the cell 6 equal to the atmosphere.

  The light source 7 is provided in the cell 6 and at one end 6 b of the cell 6. The light source 7 emits infrared light as light toward the other end portion 6 c of the cell 6 by applying a voltage. Moreover, as this light source, a black body furnace, a light bulb, etc. are used, for example.

  3 and 4, the light receiving unit 8 includes a unit main body 11 as a box-shaped member, a split member 12, infrared sensors 14a, 14b, 14c, and 14d as four sensors, and four filters. 15 a, 15 b, 15 c, 15 d and a light collecting member 13. The unit main body 11, that is, the light receiving unit 8 is provided in the cell 6 and at the other end 6 c of the cell 6.

  The unit body 11 is formed in a box shape in which an opening 11a is formed on the side facing the light source 7 and the outer shape is formed in a columnar shape.

  The dividing member 12 is disposed in the unit main body 11 and includes a first dividing plate 12a and a second dividing plate 12b. The first divided plate 12a and the second divided plate 12b are formed in a plate shape extending along the direction from the one end 6b of the cell 6 toward the other end 6c. The first divided plate 12a and the second divided plate 12b are integrally formed with each other in a direction in which the plane directions are orthogonal to each other. That is, the dividing member 12 is formed in a cross shape in plan view. Such a dividing member 12 divides the space in the unit main body 11 into four spaces 10a, 10b, 10c, and 10d having the same volume. The opening 11a is formed across these four spaces 10a, 10b, 10c, and 10d.

  The four infrared sensors 14a, 14b, 14c, and 14d have the same configuration, and are arranged one by one in each of the four spaces 10a, 10b, 10c, and 10d described above, and the opening of the unit body 11 It is attached to the side away from 11a, that is, the other end 6c side of the cell 6 (see FIG. 4). That is, the plurality of infrared sensors 14a, 14b, 14c, and 14d are arranged on the same plane, and the respective light receiving surfaces are arranged perpendicular to the direction from the one end 6b to the other end 6c. In addition, these infrared sensors 14a, 14b, 14c, and 14d are, for example, pyroelectric type or thermopile type. Such infrared sensors 14a, 14b, 14c, and 14d receive infrared rays emitted by the light source 7 and transmitted through filters 15a, 15b, 15c, and 15d described later, and convert the infrared heat into electrical energy. It outputs to μcom5 as a sensor output.

  The four filters 15a, 15b, 15c, and 15d are provided corresponding to the four spaces 10a, 10b, 10c, and 10d, respectively, and are attached to the unit body 11 so as to cover the opening 11a. The infrared sensors 14a, 14b, 14c, 14d and the light source 7 are disposed. In other words, the plurality of filters 15a, 15b, 15c, and 15d are arranged on the same plane.

  The filters 15a, 15b, 15c, and 15d transmit only infrared light having a predetermined wavelength out of the infrared light from the light source 7, and transmit the infrared light having the transmitted wavelength to the infrared sensors 14a, 14b, and 14c. , 14d. That is, the plurality of filters 15a, 15b, 15c, and 15d have different wavelengths of infrared rays that are transmitted through each other.

  The infrared wavelength transmitted through each of the filters 15a, 15b, 15c and 15d is determined by the measured concentration range for the gas whose concentration is to be measured by the concentration measuring device 1. That is, the infrared wavelength that passes through each of the filters 15a, 15b, 15c, and 15d is selected as the infrared wavelength that is most easily attenuated if the measurement range is on the order of 0 ppm to several thousand ppm. It is chosen appropriately according to.

  In the present embodiment, the infrared sensor 14a disposed in the space 10a and the filter 15a disposed on the opening 11a side of the space 10a are provided for measuring the concentration of carbon dioxide. In addition, for example, in the present embodiment, the filter 15a is provided so as to transmit only infrared rays having a wavelength of 4.27 μm that is easily attenuated in carbon dioxide.

  In this embodiment, the infrared sensor 14b disposed in the space 10b and the filter 15b disposed on the opening 11a side of the space 10b are provided for measuring the concentration of water vapor. In addition, for example, in the present embodiment, the filter 15b is provided so as to transmit only 1.9 μm of infrared light having a wavelength that is easily attenuated in water vapor.

  In the present embodiment, the infrared sensor 14c disposed in the space 10c and the filter 15c disposed on the opening 11a side of the space 10c are provided for measuring the concentration of carbon monoxide. Further, for example, in the present embodiment, the filter 15c is provided so as to transmit only infrared rays having a wavelength of 4.64 μm that is easily attenuated in carbon monoxide.

  In the present embodiment, the infrared sensor 14d disposed in the space 10d and the filter 15d disposed on the opening 11a side of the space 10d are provided as a reference. Further, for example, in this embodiment, the filter 15d is provided so as to transmit only infrared rays of 4.0 μm or 1.5 μm, which is a wavelength that does not attenuate at all in the atmosphere.

  Note that the filters 15a, 15b, 15c, and 15d of the present invention are not necessarily provided so as to transmit only the infrared rays having the wavelengths described above, and as described above, the filters 15a, 15b, 15c, and 15d are provided according to the measured concentration range of the gas to be measured. Thus, it is only necessary to provide infrared rays having a wavelength optimal for measuring the concentration of these gases.

  6 shows the infrared transmittance for carbon dioxide, the horizontal axis in FIG. 6 indicates the wavelength of infrared rays (μm), and the vertical axis in FIG. 6 indicates the infrared transmittance (%). ing. FIG. 6 shows that the transmittance of infrared rays having a wavelength of 4.27 μm in carbon dioxide is substantially zero, and infrared rays having a wavelength of 4.27 μm hardly pass through carbon dioxide ( It is almost absorbed).

  The condensing member 13 is arranged on the light source 7 side, that is, on the one end portion 6b side of the cell 6 with respect to the unit main body 11 described above. The condensing member 13 condenses infrared rays in a predetermined angle range such as 300 degrees, and concentrates them on the filters 15a, 15b, 15c, and 15d, that is, the infrared sensors 14a, 14b, 14c, and 14d. As a result, in addition to the infrared rays directly incident from the light source 7, infrared rays reflected from the inner surface of the outer wall 6a of the cell 6 can be collected in the infrared sensors 14a, 14b, 14c, and 14d. be able to. Note that a Fresnel lens or the like can be used as the light collecting member 13.

  As shown in FIG. 2, the control circuit unit 3 includes an oscillator 16, a clock frequency dividing circuit 17, a constant voltage circuit 18, and the like, and blinks the light source 7 at a predetermined frequency according to a command of μcom5.

  As shown in FIG. 5, the light receiving circuit unit 4 includes a plurality of amplifiers 19, a switcher 20, and an A / D converter 21. The amplifiers 19 are provided in one-to-one correspondence with the infrared sensors 14a, 14b, 14c, and 14d, respectively. The amplifier 19 amplifies signals from the corresponding infrared sensors 14 a, 14 b, 14 c, and 14 d and outputs the amplified signals toward the A / D converter 21 via the switcher 20. The A / D converter 21 converts the signals from the infrared sensors 14a, 14b, 14c, and 14d into digital signals and outputs them to μcom5.

  The μcom 5 is connected to the control circuit unit 3 and the light receiving circuit unit 4 and controls these operations, thereby controlling the entire operation of the concentration measuring apparatus 1. μcom5 is a computer that operates according to a predetermined program. As is well known, this μcom 5 is a central processing unit (CPU) that performs various processes and controls in accordance with a predetermined program, a ROM that is a read-only memory storing a program for the CPU, and various data. And a RAM that is a read-only memory having an area necessary for processing operations of the CPU.

  In addition, memory content (EEPROM) connected to μcom 5 can be stored even when the concentration measuring apparatus 1 itself is in an off state, and can be electrically erased and rewritten, and can be read and written. The memory stores various information such as an extinction coefficient, a measurement distance, and a concentration conversion coefficient necessary for calculating the concentration, and stores the calculated concentration in a time series so that it can be read from the outside.

  The operation of the concentration measuring apparatus 1 having the above-described configuration will be described below. First, when the oscillator 16 oscillates and outputs a pulse signal, the clock frequency dividing circuit 17 divides the pulse signal and outputs a pulse signal having a desired frequency to the constant voltage circuit 18. The constant voltage circuit 18 supplies a constant voltage to the light source 7 according to the input of the pulse signal from the clock frequency dividing circuit 17, and interrupts the supply of the constant voltage to the light source 7 according to the interruption of the pulse signal. Thereby, a pulsed constant voltage is supplied to the light source 7, and the light source 7 blinks.

  When a constant voltage is supplied to the light source 7 as described above, infrared rays from the light source 7 enter the cell 6 and enter the spaces 10a, 10b, 10c, and 10d of the unit body 11. At this time, only infrared rays having wavelengths determined according to the gas to be measured are transmitted through the filters 15a, 15b, 15c, and 15d and are incident on the spaces 10a, 10b, 10c, and 10d. The infrared rays transmitted through the filters 15a, 15b, 15c, and 15d travel through the spaces 10a, 10b, 10c, and 10d toward the infrared sensors 14a, 14b, 14c, and 14d, respectively. , 14b, 14c, and 14d.

  In the present invention, since the four spaces 10a, 10b, 10c, and 10d are separated from each other by the dividing member 12, the infrared rays that have passed through one filter (for example, 15a) are temporarily transmitted to this one filter (for example, 15a). Even when traveling toward other spaces (10b, 10c, 10d) other than the one space (10a) where the infrared rays are arranged, the infrared rays are reflected by hitting the dividing member 12 to be reflected in one space (10a). It is received by the infrared sensor (14a) and is not received by the other infrared sensors (14b, 14c, 14d). Therefore, the concentration of a plurality of types of gases can be simultaneously measured with high accuracy by the plurality of infrared sensors 14a, 14b, 14c, and 14d arranged in the same cell 6.

  As described above, the infrared sensors 14a, 14b, 14c, and 14d that receive infrared rays output the intensity thereof as a signal toward the light receiving circuit unit 4. In addition, the light receiving circuit unit 4 converts the signals from the infrared sensors 14a, 14b, 14c, and 14d into digital signals and outputs them to the μcom5. Further, μcom5 measures the concentration in a predetermined gas atmosphere based on the intensity of infrared rays received by each of the infrared sensors 14a, 14b, 14c, and 14d.

  Specifically, μcom 5 of the concentration measuring apparatus 1 measures the intensity of infrared light received by the infrared sensor 14d used as a reference, the intensity of infrared light received by the infrared sensor 14a for measuring carbon dioxide, and water vapor. For comparing the intensity of the infrared light received by the infrared sensor 14b for use with the intensity of the infrared light received by the infrared sensor 14c for measuring carbon monoxide, and the concentration of carbon dioxide, water vapor, and carbon monoxide to be measured Measure.

  According to the present embodiment, the concentration measuring apparatus 1 includes four filters 15a, 15b, 15c, and 15d having different infrared wavelengths that are transmitted from each other, and four infrared sensors 14a, 14b, 14c, and 14d corresponding to these filters, Since the gas sample chamber 2 in which the light receiving unit 8 having the above is disposed is provided, it is possible to simultaneously measure the concentrations of a plurality of types of gases contained in the atmosphere and to reduce the size thereof.

  Since the space between the four filters 15a, 15b, 15c, and 15d and the four infrared sensors 14a, 14b, 14c, and 14d is divided into four by the dividing member 12, one filter (for example, 15a ) Transmitted through other infrared sensors (14b, 14c, 10d) other than one space (10a) in which this one filter (for example, 15a) is arranged. 14d), it is possible to perform accurate concentration measurement without being received.

  Further, the four infrared sensors 14a, 14b, 14c, and 14d are arranged in the same package, that is, the unit main body 11, and further receive infrared rays from the same light source 7, so that temperature conditions, deterioration of the light source 7 with time, etc. All the environmental conditions are the same, and the sensitivity correction for the environmental characteristics between the four infrared sensors 14a, 14b, 14c, and 14d can be easily performed.

  Further, since the gas sample chamber 2 does not have a mechanical drive system, it is possible to perform stable concentration measurement over a long period of time.

(Second Embodiment)
Next, a concentration measuring apparatus according to a second embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  The concentration measuring apparatus of the present embodiment has a gas sample chamber (see FIG. 1) having the light receiving unit 108 shown in FIG. 7, and the other configuration is the same as that of the first embodiment.

  The light receiving unit 108 includes a unit main body 11, a dividing member 112, four infrared sensors 14a, 14b, 14c, and 14d (not shown), four filters 115a, 115b, 115c, and 115d, and a light collecting member 13 ( (Not shown). Further, the unit main body 11, that is, the light receiving unit 108 is provided in the cell 6 and at the other end 6c of the cell 6 (see FIG. 1).

  The dividing member 112 includes four dividing plates 112 a arranged in the unit main body 11. Each of the divided plates 112a is formed in a plate shape extending in a direction (see FIG. 1) from the one end 6b to the other end 6c of the cell 6, and one end in the width direction is connected to each other. The other end in the width direction is connected to the inner surface of the unit body 11 and is integrally formed with each other. Such a dividing member 112 divides the space in the unit main body 11 into four spaces 110a, 110b, 110c, and 110d having different volumes. Of the four spaces 110a, 110b, 110c, and 110d, the space 110a having the largest volume measures the concentration of the lowest concentration gas among a plurality of types of gases to be measured in the atmosphere. It is a space provided to do. The opening 11a of the unit main body 11 is formed across these four spaces 110a, 110b, 110c, and 110d.

  The four infrared sensors 14a, 14b, 14c, and 14d have the same configuration, and are arranged one by one in each of the four spaces 110a, 110b, 110c, and 110d described above, as in the first embodiment. At the same time, the unit body 11 is attached to the side away from the opening 11a, that is, the other end 6c side of the cell 6.

  The four filters 115a, 115b, 115c, and 115d are provided corresponding to the four spaces 110a, 110b, 110c, and 110d, respectively, and cover the opening 11a of the unit main body 11 so as to cover the unit main body 11. Attached and disposed between the infrared sensors 14 a, 14 b, 14 c, 14 d and the light source 7.

  In the concentration measuring apparatus having the light receiving unit 108 having the above-described configuration, when a constant voltage is supplied to the light source 7 as in the first embodiment, infrared light from the light source 7 enters the cell 6 and The light enters the spaces 110a, 110b, 110c, and 110d. At this time, only infrared rays having wavelengths determined according to the gas to be measured are transmitted through the filters 115a, 115b, 115c, and 115d and are incident on the spaces 110a, 110b, 110c, and 110d. The infrared rays transmitted through the filters 115a, 115b, 115c, and 115d travel through the spaces 110a, 110b, 110c, and 110d toward the infrared sensors 14a, 14b, 14c, and 14d, respectively. , 14b, 14c, and 14d. And the density | concentration in the atmosphere of predetermined gas is measured similarly to 1st Embodiment.

  According to this embodiment, the volume of the space 110a for measuring the concentration of the lowest concentration gas among the plurality of types of gases to be measured in the atmosphere is larger than the volumes of the other spaces 110b, 110c, and 110d. Since it is formed, the amount of infrared light received by the infrared sensor 14a disposed in the space 110a can be increased, so that the concentration of the lowest concentration gas can be measured with high accuracy.

  As described above, in the present invention, the space in the unit main body 11 is divided into a plurality of spaces 110a, 110b, 110c, and 110d having different volumes according to the concentration of the gas to be measured. The concentration can be measured with high accuracy.

(Third embodiment)
Next, a concentration measuring apparatus according to the third embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted.

  The concentration measuring apparatus of the present embodiment has a gas sample chamber (see FIG. 1) having a light receiving unit 208 shown in FIG. 8, and the other configuration is the same as that of the first embodiment.

  The light receiving unit 208 includes a unit main body 11, a split member 12, four infrared sensors 14a, 14b, 14c, and 14d, four filters 15a, 15b, 15c, and 15d, and a light collecting member 13. ing. The unit main body 11, that is, the light receiving unit 208 is provided in the cell 6 and at the other end 6 c of the cell 6 (see FIG. 1).

  The four infrared sensors 14a, 14b, 14c, and 14d have the same configuration, and are arranged one by one in each of the four spaces 10a, 10b, 10c, and 10d, and apart from the opening 11a of the unit body 11. It is attached to the other side, that is, the other end portion 6 c side of the cell 6.

    The four infrared sensors 14a, 14b, 14c, and 14d are inclined with respect to a direction (indicated by an arrow K in FIG. 8) in which each light receiving surface faces from one end 6b of the cell 6 to the other end 6c. It is arranged. Further, the distances from the edges of the light receiving surfaces of these four infrared sensors 14a, 14b, 14c, and 14d and closest to the opening 11a to the opening 11a are equal to each other. Further, the edges of the light receiving surfaces of these four infrared sensors 14a, 14b, 14c, and 14d and the edges that are positioned furthest away from the opening 11a are positioned in the same plane.

  According to this embodiment, the light receiving surfaces of the four infrared sensors 14a, 14b, 14c, and 14d are arranged to be inclined with respect to the direction K from the one end portion 6b to the other end portion 6c. To the edge of the light receiving surface of the four infrared sensors 14a, 14b, 14c, 14d and the edge positioned closest to the opening 11a, that is, from the light source 7 to each of the infrared sensors 14a, 14b, 14c, 14d. Therefore, each infrared sensor 14a, 14b, 14c, 14d can receive a large amount of infrared rays before the infrared rays transmitted through the filters 15a, 15b, 15c, 15d are diffused. The concentration of each gas can be measured with high accuracy.

  In the first to third embodiments described above, infrared light is used as light. However, in the present invention, various light other than infrared light may be used.

In the first to third embodiments described above, the concentration measuring device 1 measures the concentrations of carbon dioxide, water vapor, and carbon monoxide. However, in the present invention, even if the concentration measuring apparatus 1 measures the concentrations of various gases other than carbon dioxide such as NO _x , SO _x , H ₂ S, O ₃ , CH ₄ , NO, water vapor, and carbon monoxide. good.

  In the first to third embodiments described above, the dividing members 12 and 112 divide the space in the unit main body 11 into four spaces 10a, 10b, 10c, 10d / 110a, 110b, 110c, and 110d. However, the present invention is not limited to “four spaces”, and includes all of the dividing members that divide the space in the unit main body 11 into two or more spaces.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

It is a perspective view which shows typically the structure of the gas sample chamber which comprises the density | concentration measuring apparatus concerning the 1st Embodiment of this invention. It is explanatory drawing which shows the structure of the density | concentration measuring apparatus shown by FIG. It is explanatory drawing which shows typically the front of the light-receiving unit of the gas sample chamber shown by FIG. It is explanatory drawing which shows typically the cross section along the AA in FIG. It is explanatory drawing which shows the structure of the light-receiving circuit of the density | concentration measuring apparatus shown by FIG. It is the graph which showed the transmittance | permeability of the infrared rays with respect to a carbon dioxide. It is explanatory drawing which shows typically the front of the light-receiving unit which comprises the density | concentration measuring apparatus concerning the 2nd Embodiment of this invention. It is explanatory drawing which shows typically the cross section of the light-receiving unit which comprises the density | concentration measuring apparatus concerning the 3rd Embodiment of this invention.

Explanation of symbols

1 Concentration measuring device 2 Gas sample chamber 5 Microcomputer (concentration calculator)
6 cells 7 light sources 8, 108, 208 light receiving units 10a, 10b, 10c, 10d space 11 unit body (box-shaped member)
11a Opening 12, 112 Split member 14a, 14b, 14c, 14d Infrared sensor (sensor)
15a, 15b, 15c, 15d filter 110a, 110b, 110c, 110d space 115a, 115b, 115c, 115d filter

Claims (4)

A light receiving unit disposed at the other end of the cell for receiving light from a light source disposed at one end of the cell filled with an atmosphere,
A box-shaped box-shaped member having an opening formed on the side facing the light source;
A dividing member that extends along the direction from the one end to the other end, and divides the internal space of the box-shaped member into a plurality of spaces;
A plurality of filters that are respectively arranged on the opening side of the plurality of spaces, transmit only light of a predetermined wavelength and transmit different wavelengths of light from each other;
A plurality of sensors arranged in each of the plurality of spaces and receiving light transmitted through the filter;
A light receiving unit characterized by comprising: The light receiving unit according to claim 1, wherein the dividing member divides the space in the unit main body into a plurality of spaces having different volumes. 3. The light receiving unit according to claim 1, wherein light receiving surfaces of the plurality of sensors are inclined with respect to a direction from the one end portion toward the other end portion. A gas sample chamber in which a light source is arranged at one end in the cell, and a light receiving unit for receiving light from the light source is arranged at the other end;
In a concentration measuring device having a concentration calculation unit that calculates a concentration of a predetermined gas in the gas sample chamber based on the intensity of light from the light source received by the light receiving unit,
A concentration measuring apparatus comprising the light receiving unit according to claim 1 as the light receiving unit.

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