JP2009145125A - Gas sample chamber and concentration measuring instrument equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sample chamber capable of rapidly measuring the concentration of the gas to be measured in an atmosphere and capable of preventing penetrated foreign matter from becoming the measuring obstruction of the concentration of the gas to be measured, and to provide a concentration measuring instrument equipped with the chamber. <P>SOLUTION: The concentration measuring instrument 1 is equipped with the gas sample chamber 2 and microcomputer. The gas sample chamber 2 is equipped with a measuring cell 6, a light source 7 and a light-receiving unit 8. An atmosphere movement permitting part 9, equipped with a plurality of through-holes 10, is provided in the measuring cell 6. The through-holes 10 are provided to the outer wall 6a, positioned at the upper part and the outer wall 6a positioned at the lower part to be opposed to each other in a vertical direction. The light source 7 emits infrared rays of the measuring cell 6, and the light-receiving unit 8 is equipped with a plurality of light-receiving devices 12 and condensing members 13. The light-receiving devices 12 receive the infrared rays from the light source 7 and the condensing members 13 condense infrared rays to the light-receiving devices 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas sample chamber used for a concentration measuring device that measures the concentration of a predetermined gas such as carbon dioxide, water vapor, carbon monoxide, and the like, and a concentration measuring device including the gas sample chamber.

  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 main body with a sealed interior, a light source provided at one end of the main body, a light receiver provided at the other end of the main body, and an external device within the main body. And a gas supply unit for forcibly supplying the atmosphere.

  The inner surface of the main body is formed as a mirror surface. The light source emits infrared rays, for example. 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 rays having a predetermined wavelength. The wavelength of infrared rays that pass through the filter is determined by the concentration of the gas to be measured. For example, if the concentration of the gas to be measured is within the range of 0 ppm to several thousand ppm, the infrared wavelength that passes through the filter is set to the concentration of the gas to be measured by selecting the infrared wavelength that is most easily attenuated. Appropriately selected accordingly. The gas supply unit includes a pump, piping, and the like, forcibly supplies an atmosphere into the main body, and forcibly discharges the gas in the main body.

  In the conventional gas sample chamber, that is, the concentration measuring device described above, the gas supply unit forcibly supplies the atmosphere into the main body unit, and measures the intensity of infrared rays from the light source received by the infrared sensor through the filter. The concentration of the measurement target gas in the atmosphere is measured.

  However, since the conventional gas sample chamber described above includes a gas supply unit that forcibly supplies an atmosphere into the main body, the apparatus itself tends to be large and foreign substances such as dust are present in the gas supply unit. If accumulated, the atmosphere cannot be smoothly supplied into the main body, and it becomes difficult to accurately measure the concentration of the gas to be measured in the atmosphere.

  In order to solve this type of problem, for example, a gas sample chamber disclosed in Patent Document 1 has been proposed. The gas sample chamber shown in Patent Document 1 is provided in a hollow tube as a cylindrical main body with the inside sealed, a light source provided at one end of the hollow tube, and the other end of the hollow tube. And a light receiver.

The inner surface of the hollow tube is formed in a mirror shape, and a plurality of openings are provided on the outer wall. Moreover, the semipermeable membrane sheet which closed the opening part mentioned above is attached to the hollow tube. This semipermeable membrane sheet allows a gas floating particle smaller than a predetermined dimension to pass and move inside and outside the hollow tube, and restricts the passage of gas floating particles larger than a predetermined dimension to the hollow tube. Restrict movement inside and outside. Thus, by providing the semipermeable membrane sheet, the gas sample chamber shown in Patent Document 1 allows the atmosphere to freely enter and exit the hollow tube without providing a gas supply unit.
Japanese Patent No. 3606866

  However, in the gas sample chamber shown in Patent Document 1 described above, the semipermeable membrane sheet attached to the hollow tube is easily clogged with dust or dust (gas suspended particles), and the atmosphere is quickly guided into the hollow tube. It was a tendency to become difficult. For this reason, the gas sample chamber shown in Patent Document 1 tends to be difficult to quickly measure the concentration of the gas to be measured in the atmosphere.

  For this reason, in order to make it possible to quickly measure the concentration of the gas to be measured in the atmosphere, it is conceivable not to provide a semipermeable membrane sheet that closes the opening, but in this case, in the hollow tube It is conceivable that foreign matters are likely to enter, and the foreign matters interfere with the measurement of the concentration of the gas to be measured.

  Therefore, an object of the present invention is to enable the measurement of the concentration of the gas to be measured in the atmosphere quickly and to prevent the intruding foreign matter from interfering with the measurement of the concentration of the gas to be measured. An object of the present invention is to provide a sample chamber and a concentration measuring device including the gas sample chamber.

  In order to solve the problems and achieve the object, the gas sample chamber of the present invention according to claim 1 is a gas sample chamber that guides light from a light source to a light receiver. The light source disposed at one end of the main body, the light receiver disposed at the other end of the main body and receiving light from the light source, and the atmosphere can be moved in and out of the main body. An atmosphere movement allowance portion, and the atmosphere movement allowance portion is provided on both an outer wall located at an upper portion of the main body portion and an outer wall located at a lower portion, and provided at positions facing each other in the vertical direction. It is characterized by having a through hole.

  A gas sample chamber according to a second aspect of the present invention is the gas sample chamber according to the first aspect, further comprising a reflector that converts the light emitted from the light source into parallel light.

  A gas sample chamber according to a third aspect of the present invention is the gas sample chamber according to the first or second aspect, wherein the light receiver includes a sensor that receives the light, and the sensor and the light source. A transmission member that transmits only light of a predetermined wavelength, and further includes a light collection member that is disposed between the transmission member and the light source and condenses the light on the transmission member. It is characterized by that.

  The gas sample chamber according to a fourth aspect of the present invention is the gas sample chamber according to the third aspect, wherein the gas sample chamber includes a plurality of the light receivers, and the wavelengths of light transmitted through the transmission members of the plurality of light receivers are different from each other. It is characterized by that.

  The concentration measuring apparatus of the present invention according to claim 5 is a gas sample chamber provided with a light source at one end and a light receiver for receiving light from the light source at the other end, and the light received by the light receiver. A concentration measurement device comprising: a concentration calculation unit that calculates a predetermined gas concentration in the gas sample chamber based on the intensity of light from a light source. The gas sample chamber according to any one of Items 4 is provided.

  According to the first aspect of the present invention, since the atmosphere movement allowing portion includes the through hole penetrating the outer wall of the main body portion, the atmosphere is taken in and out of the main body portion without clogging the through hole. You can do it freely.

  Moreover, since the through holes are provided in both the upper part and the lower part of the main body part, and these through holes are provided in positions opposed to each other in the vertical direction, foreign matter that has entered the main body part is provided in the lower part. It can be quickly guided out of the main body through the hole.

  According to the second aspect of the present invention, since the reflector is provided, the light from the light source can be guided to the light receiver without being reflected by the inner surface of the main body.

  According to the third aspect of the present invention, since the light collecting member is provided, even if the light from the light source leaks out of the main body through the through hole, the light reflected by the outer wall of the main body is received by the light receiver. And a sufficiently strong light can be guided to the transmission member or sensor.

  According to the fourth aspect of the present invention, since a plurality of light receivers having different wavelengths transmitted by the transmission member are provided, it can be used to measure the concentrations of a plurality of types of gases.

  According to the fifth aspect of the present invention, since the gas sample chamber described above is provided, the atmosphere can be taken into and out of the main body of the gas sample chamber.

  As described above, according to the first aspect of the present invention, since the atmosphere movement allowing portion allows the atmosphere to be taken in and out of the main body, the atmosphere is promptly introduced into the main body and the gas to be measured in the atmosphere is measured. It becomes possible to measure the density | concentration of swiftly.

  In addition, since the foreign matter that has entered the main body can be quickly guided out of the main body, it is possible to prevent the through hole from being blocked by the foreign matter and making it difficult for the atmosphere to enter and exit, and the foreign matter that has entered the main body can be used as a light source. Can prevent light from being blocked. Therefore, it is possible to quickly and reliably measure the concentration of the gas to be measured in the atmosphere.

  According to the second aspect of the present invention, since the light from the light source can be guided to the light receiver without being reflected by the inner surface of the main body, even if a through-hole penetrating the outer wall of the main body is provided, the light can be received. The concentration of the gas to be measured in the atmosphere can be reliably measured.

  According to the third aspect of the present invention, even if light from the light source leaks out of the main body through the through hole, sufficient intensity of light can be guided to the transmission member, that is, the sensor. The concentration of the gas to be measured in the atmosphere can be reliably measured.

  The present invention according to claim 4 can be used to measure the concentrations of a plurality of types of gases.

  Since the gas sample chamber described above is provided, the present invention according to claim 5 can quickly measure the concentration of the gas to be measured in the atmosphere.

  Hereinafter, a concentration measuring apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

  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 measurement cell 6 as a main body, a light source 7, and a light receiving unit 8. The measurement cell 6 is formed in a cylindrical shape. In the illustrated example, the measurement cell 6 is formed in a square cylinder shape. The measurement cell 6 is provided with an atmosphere movement allowing portion 9. In other words, the gas sample chamber 2 includes an atmosphere movement allowance unit 9.

  The atmosphere movement allowing portion 9 includes a plurality of through holes 10. The through hole 10 penetrates the outer wall 6 a of the measurement cell 6 and communicates the inside and outside of the gas sample chamber 2. The through hole 10 is provided in both the outer wall 6a located in the upper part of the gas sample chamber 2 and the outer wall 6a located in the lower part. In each outer wall 6a, a plurality of through holes 10 (four in the illustrated example) are provided. K These through holes 10 are arranged at equal intervals along the optical axis of the light from the light source 7 toward the light receiving unit 8. The through hole 10 provided in the outer wall 6a located in the upper part of the gas sample chamber 2 and the through hole 10 provided in the outer wall 6a located in the lower part are provided in positions facing each other in the vertical direction. Each through hole 10 is formed in a round shape having the same inner diameter R. In the present invention, it is desirable that the inner diameter R of the through hole 10 is about 2 mm, and the distance d between the through hole 10 closest to the light receiving unit 6 and the light receiving unit 6 among the plurality of through holes 10 is 8 mm. It is desirable to be provided at a position where the degree is reached. The through-hole 10 is formed to be much larger than gas suspended particles such as dust in the atmosphere, and allows the atmosphere to pass through the inside, and moves the atmosphere inside and outside the measurement cell 6, that is, the gas sample chamber 2. It is free. Furthermore, the through-hole 10 allows the foreign material that has entered the gas sample chamber 2 through the through-hole 10 provided in the outer wall 6a located in the upper part to quickly pass through the through-hole 10 provided in the outer wall 6a located in the lower part to obtain the gas sample Drain outside the chamber 2.

  In the present invention, the atmosphere movement allowing portion 9 is provided with a through hole 10 that is much larger than gas suspended particles such as dust in the atmosphere, and is opened without closing the through hole 10 with a filter or the like. Can be moved in and out of the measuring cell 6. That is, the atmosphere movement permitting portion 9 of the present invention quickly introduces the atmosphere into the measurement cell 6 without providing a blower or a pump, and quickly makes the gas in the measurement cell 6 equal to the atmosphere. .

  The light source 7 is provided in the measurement cell 6 and at one end of the measurement cell 6. The light source 7 emits infrared light as light toward the other end of the measurement cell 6 by applying a voltage. As the light source, for example, a black body furnace or a light bulb is used. A reflector 30 is attached to the light source 7. That is, the concentration measuring apparatus 1 includes a reflector 30. The reflector 7 reflects the light emitted from the light source 7 into parallel light directed to the light receiving unit 8.

  As shown in FIGS. 3 and 4, the light receiving unit 8 includes a unit main body 11, a plurality of light receivers 12, and a light collecting member 13. The unit main body 11, that is, the light receiving unit 8 is provided in the measurement cell 6 and at the other end of the measurement cell 6. The unit main body 11 is formed in a box shape.

  In the illustrated example, four light receivers 12 are provided. Each of the light receivers 12 includes an infrared sensor 14 as a sensor and a transmission member 15. The infrared sensor 14 is attached to the unit main body 11. The infrared sensors 14 of the plurality of light receivers 12 are arranged on the same plane. The infrared sensor 14 receives infrared rays emitted from the light source 7 and transmitted through the transmission member 15 and converts the heat of the infrared rays into electric energy. The infrared sensor 14 converts infrared heat into electrical energy, and outputs it to the μcom 5 as a sensor output. As the infrared sensor 14, for example, a pyroelectric type or a thermopile type is used.

  The transmission member 15 is attached to the unit body 11 and is disposed between the infrared sensor 14 and the light source 7. The transmission members 15 of the plurality of light receivers 12 are arranged on the same plane. Each of the transmissive members 15 transmits only infrared rays having a predetermined wavelength out of infrared rays from the light source 7 and guides the infrared rays having the transmitted wavelengths to the infrared sensor 14. The transmission members 15 of the plurality of light receivers 12 have different wavelengths of infrared rays that pass through each other.

  The wavelength of infrared rays that pass through the transmissive member 15 is determined according to the gas that the concentration measuring device 1 is to measure the concentration of. In the illustrated example, it is possible to detect a low concentration within the measurement concentration range of the gas to be measured within the range of 0 ppm to several thousand ppm, and the wavelength of the infrared ray transmitted through the transmission member 15 is the concentration measurement target. The transmittance of the gas to the gas is set to a small infrared wavelength. The light receiver 12 uses water vapor and carbon monoxide as the measurement target gas in addition to carbon dioxide. In the illustrated example, for example, one light receiver 12 is used as a reference, and the transmitting member 15 transmits only infrared rays having a wavelength of 1.5 μm or 4.0 μm that does not attenuate at all in the atmosphere. In the illustrated example, for example, another one of the light receivers 12 is used for measuring the concentration of carbon dioxide, and the transmission member 15 only receives infrared rays having a wavelength of 4.27 μm that is easily attenuated in carbon dioxide. To Penetrate. In the illustrated example, for example, still another light receiver 12 is used for measuring the concentration of water vapor, and the transmission member 15 transmits only infrared light having a wavelength of 1.9 μm that is easily attenuated in the water vapor. In the illustrated example, for example, another light receiver 12 is used to measure the concentration of carbon monoxide, and only the infrared ray whose wavelength is easily attenuated in the above-described carbon monoxide by the transmitting member 15 is 4.64 μm. Transparent.

  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 condenses infrared rays in a range of a predetermined angle such as 300 degrees and concentrates it on the transmissive member 15, that is, the infrared sensor 4. Then, in addition to the infrared rays directly incident from the light source 7, infrared rays reflected by the inner surface of the outer wall 6a of the measurement cell 6 can be collected in the infrared sensor 5, so that the infrared light receiving efficiency can be improved. 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 in one-to-one correspondence with the light receivers 12. Correspondingly provided. The amplifier 19 amplifies the signal from the infrared sensor 14 of the corresponding light receiver 12 and outputs it to the A / D converter 21 via the switcher 20. The A / D converter 21 converts the signal from the infrared sensor 14 into a digital signal and outputs it to the μcom 5.

  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 operation of the concentration measuring apparatus 1 as a whole. 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 readable / writable memory having an area necessary for processing operations of the CPU.

  In addition, the μcom 5 is connected to an electrically erasable / rewritable read-only memory capable of holding stored contents even when the concentration measuring apparatus 1 itself is in an OFF state. The memory stores various information such as an extinction coefficient, measurement distance, and concentration conversion coefficient, which will be described later, necessary for calculating the concentration, and stores the calculated concentration in a time series so that it can be read from the outside.

  In the concentration measuring apparatus 1 having the above-described configuration, the atmosphere can freely move in and out of the measurement cell 6 by the plurality of through holes 10 of the atmosphere movement permitting portion 9, and the gas in the measurement cell 6, that is, the gas sample chamber 2 is transferred. Make it equal to the atmosphere. Then, the concentration measuring apparatus 1 blinks the light source 7 and receives the infrared light from the light source 7 by the infrared sensor 14 of each light receiver 12. The μcom 5 of the concentration measuring apparatus 1 measures the concentration in a predetermined gas atmosphere based on the intensity of infrared rays received by the infrared sensor 14. Specifically, the μcom 5 of the concentration measuring apparatus 1 determines the intensity of infrared light received by the infrared sensor 14 of the light receiver 12 used as a reference, and the infrared light of the light receiver 12 for measuring carbon dioxide, water vapor, and carbon monoxide. The concentration of carbon dioxide, water vapor, and carbon monoxide to be measured is measured by comparing the intensity of infrared rays received by the sensor 14. As described above, the gas sample chamber 2 of the concentration measuring apparatus 1 is formed so as to guide the infrared rays from the light source 7 to the light receiver 12.

  According to the present embodiment, the atmosphere movement allowing portion 9 includes the through hole 10 that penetrates the outer wall 6a of the measurement cell 6 and is opened without being blocked by a filter or the like, and thus the through hole 10 is clogged. Therefore, the atmosphere can be taken into and out of the measuring cell 6 without any change. For this reason, the atmosphere is promptly introduced into the measurement cell 6 and the concentration of the gas to be measured in the atmosphere can be measured quickly.

  Moreover, since the through-hole 10 is provided in both the upper part and the lower part of the measurement cell 6 and is opposed to the vertical direction, the foreign matter that has entered the measurement cell 6 is introduced into the through-hole 10 provided in the lower outer wall 6a. Through, it is possible to quickly lead out of the measuring cell 6. For this reason, it is possible to prevent the through hole 10 from being blocked by the foreign matter, making it difficult for the atmosphere to enter and exit, and to prevent the foreign matter that has entered the measurement cell 6 from blocking the light from the light source 7. Therefore, it is possible to quickly and reliably measure the concentration of the gas to be measured in the atmosphere.

  Furthermore, since the reflector 30 is provided, the light from the light source 7 can be guided to the light receiver 12 without being reflected by the inner surface of the measurement cell 6. Therefore, even if the through hole 10 penetrating the outer wall 6a of the measurement cell 6 is provided, light can be guided to the light receiver 12, and the concentration of the gas to be measured in the atmosphere can be reliably measured. .

  Since the light collecting member 13 is provided, the infrared light reflected from the inner surface of the outer wall 6 a can be guided to the light receiver 12 even if infrared light as light from the light source 7 leaks out of the measurement cell 6 through the through hole 10. , A sufficiently strong infrared ray can be guided to the transmission member 15, that is, the infrared sensor 14. For this reason, even if the through hole 10 is provided, the concentration of the gas to be measured in the atmosphere can be reliably measured.

  Since a plurality of light receivers 12 having different infrared wavelengths transmitted by the transmissive member 15 are provided, they can be used to measure the concentrations of a plurality of types of gases.

  In the embodiment described above, infrared rays are used as light. However, in the present invention, various light other than infrared light may be used. Further, in the above-described embodiment, the wavelength of the infrared ray transmitted through the transmission member 15 when the concentration of the measurement target gas is low is shown. However, in the present invention, the measurement target gas has a low concentration to a high concentration. When it is within the range of (0 ppm to several percent), the length of the measurement cell 6 is changed, or the transmitting member 15 transmits only infrared light having a wavelength with a small amount of infrared absorption in the measurement target gas. You may do it.

Furthermore, in the embodiment, 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 present invention, the measurement cell 6 may be formed in various cylindrical shapes other than the rectangular cylindrical shape.

  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 showing typically composition of a gas sample room of a concentration measuring device concerning one embodiment of the present 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 of the IV-IV line | wire in FIG. It is explanatory drawing which shows the structure of the light-receiving circuit of the density | concentration measuring apparatus shown by FIG. 3 is a graph showing an absorption spectrum of carbon dioxide.

Explanation of symbols

1 Concentration measuring device 2 Gas sample chamber 5 Microcomputer (concentration calculator)
6 Measurement Cell 7 Light Source 9 Atmosphere Movement Allowable Part 10 Through-hole 12 Light Receiver 13 Condensing Member 14 Infrared Sensor 15 Transmitting Member 30 Reflector

Claims (5)

In the gas sample chamber that guides the light from the light source to the receiver,
A main body formed in a cylindrical shape;
The light source disposed at one end of the main body;
The light receiver disposed at the other end of the main body and receiving light from the light source;
An atmosphere movement allowing portion for allowing the atmosphere to move in and out of the main body portion;
With
The atmosphere movement allowing portion is provided on both an outer wall located at an upper portion of the main body portion and an outer wall located at a lower portion, and includes a through hole provided at a position facing each other in a vertical direction. Gas sample chamber.   The gas sample chamber according to claim 1, further comprising a reflector that converts the light emitted from the light source into parallel light. The light receiver includes a sensor that receives the light, and a transmission member that is disposed between the sensor and the light source and transmits only light having a predetermined wavelength.
The gas sample chamber according to claim 1, further comprising a condensing member that is disposed between the transmissive member and the light source and condenses the light on the transmissive member.   The gas sample chamber according to claim 3, wherein a plurality of the light receivers are provided, and wavelengths of light transmitted through the transmission members of the plurality of light receivers are different from each other. A gas sample chamber provided with a light source at one end and a light receiver for receiving light from the light source at the other end;
In a concentration measuring device comprising: a concentration calculating unit that calculates a predetermined gas concentration in the gas sample chamber based on the intensity of light from the light source received by the light receiver;
A concentration measuring apparatus comprising the gas sample chamber according to any one of claims 1 to 4 as the gas sample chamber.

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