JP2013134232A - Gas analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the influence of a thermal lens effect phenomenon and improve measurement accuracy, in a gas analyzer provided with a probe for gas analysis in which the concentration of sample gas flowing in a pipe is measured by an optical measurement system.SOLUTION: A gas analyzer comprises: a probe tube 11 arranged by intersecting with a flow channel of sample gas in a pipe, to introduce sample gas flowing in the pipe into a predetermined measurement area in an internal hollow; a light emitting part and a light receiving part that irradiate the measurement area in the probe tube 11 with measurement light and receive measurement light having passed through the sample gas in the measurement area; and a purge gas supply tube 26 that is arranged in the probe tube 11 to supply an area between those optical system members and the measurement area with purge gas and that is arranged spaced from an inner wall surface of the probe tube 11.

Description

  The present invention relates to a gas analyzer, and more particularly to a gas analyzer including a gas analysis probe disposed in a pipe in order to analyze a concentration of a predetermined component in a sample gas flowing in the pipe.

Combustion exhaust gas discharged from a boiler that burns coal and heavy oil contains components such as sulfur oxide (SOx), nitrogen oxide (NOx), carbon dioxide (CO ₂ ), and carbon monoxide (CO). It is.

  As a gas analyzer for analyzing the content of each component contained in the gas, for example, a probe is arranged so as to intersect the gas flow path in the pipe, and the measurement light emitted from the light source toward the gas is used. There is one that reflects the component concentration of the sample gas based on the information of the reflected measurement light that is reflected by a reflector disposed at the tip of the probe.

  FIG. 8 is a cross-sectional view schematically showing a probe used in a conventional gas analyzer.

  The probe A shown in FIG. 8 includes a hollow pipe-shaped probe tube B through which measurement light passes, and the probe tube B is placed on the pipe side wall D so as to intersect the gas flow path in the flue C. It is attached.

  The pipe side wall D has an attachment portion E for attaching the probe A, and the probe A is attached to the attachment portion E via the flange F.

  A light emitting part G that emits measurement light into the probe tube B and a light receiving part H that receives reflected light are provided at the proximal end of the probe A, and the measurement light from the light emitting part G is received at the distal end. A reflector I that reflects toward the light receiving portion H is provided.

  In the gas analyzer using the probe A as described above, the sample gas in the flue C is introduced into the probe tube B, and the measurement light emitted from the light emitting unit G and reflected by the reflector I is received by the light receiving unit G. And it becomes possible to analyze each component in gas from the characteristic of this measurement light.

  However, when the sample gas flowing in the flue C is introduced into the probe tube B, if the sample gas reaches the optical system members such as the light emitting unit G, the light receiving unit H, and the reflector I through the probe tube B, these The optical system member is exposed to the high-temperature sample gas, and may be deteriorated due to dust contamination or corrosion.

  Therefore, in order to prevent the optical system member from being exposed to the high-temperature sample gas, a purge gas supply unit J is provided in the probe A, and purge gas is supplied between the light emitting unit G and the light receiving unit H and the measurement region of the probe tube B. Supply is done.

  In addition, a purge gas supply pipe (not shown) arranged in the probe pipe B supplies purge gas to the tip of the probe pipe B so that the reflector I is not exposed to the sample gas. Can do.

  Since the proximal end portion of the probe tube B is configured by using a plurality of parts, the inner diameter thereof is not uniform. For this reason, when the purge gas is supplied into the probe tube B, turbulent flow is generated in the purge gas in the probe tube B, which may cause a temperature difference in the optical path of the measurement light.

  If there is a temperature difference in the probe tube B, the thermal lens effect phenomenon will cause problems such as the measurement beam's laser beam fluctuating and the optical axis deviating, and the light receiving state at the light receiving unit will become unstable. There is a problem that the measurement accuracy deteriorates.

  In order to supply the purge gas to the tip of the probe tube B, a temperature difference in the probe tube B is generated at the position where the purge gas supply tube is arranged, so that a high measurement is caused by the influence of the thermal lens effect phenomenon. There is a possibility that accuracy cannot be obtained.

US Pat. No. 5,781,306

  An object of the present invention is to provide a gas analyzer having a gas analysis probe for measuring the concentration of a sample gas flowing in a pipe with an optical measurement system, to the probe by a purge gas introduced into the probe in order to protect the optical system member. It is to prevent the temperature difference from occurring, suppress the influence of the thermal lens effect phenomenon, and improve the measurement accuracy.

  Hereinafter, a plurality of modes will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.

  A gas analyzer according to an aspect of the present invention includes a tubular member, an optical system member, and a purge gas supply pipe. The tubular member projects measurement light to a predetermined measurement region of the sample gas flowing in the pipe and / or forms an optical path for receiving measurement light from the measurement region. The optical member projects and receives measurement light with respect to the sample gas in the measurement region. The purge gas supply pipe has a hollow portion including a purge gas flow path for supplying purge gas to an area between the optical system member and the measurement area and an optical path for measurement light, and is spaced from the inner wall surface of the tubular member. Arranged inside the tubular member.

  In this gas analyzer, since the purge gas supply pipe is arranged with a gap from the inner wall surface of the tubular member, the purge gas passing through the purge gas supply pipe can be insulated from the outside air. In addition, the tubular member has a joint with the flange for mounting on the side wall of the pipe, a joint with the pipe for introducing purge gas, a joint with the optical system member, etc., and the inner diameter is not uniform. Even so, by using a purge gas supply pipe having a smooth inner diameter without a step with respect to the optical axis direction, there is no turbulent flow in the purge gas, thereby suppressing the occurrence of the thermal lens effect phenomenon. . As the inner diameter of the purge gas supply pipe, for example, one having an equal inner diameter over the entire length can be used. As a result, there is no wobbling of the measurement light, the measurement accuracy of the gas analysis processing by the optical system member can be increased, and the initial setting such as optical axis adjustment at the time of installation can be facilitated in a short time.

  The purge gas flowing through the hollow portion of the purge gas supply pipe is preferably a laminar flow.

  If the Reynolds number is reduced by determining the diameter of the purge gas supply pipe in consideration of the flow rate of the purge gas flowing through the inside, turbulent flow will not occur in the purge gas and non-uniform temperature distribution will not occur. For example, as described above, by using a purge gas supply pipe having a uniform inner diameter over the entire length, and further laminating the purge gas inside, the measurement lens fluctuates due to the occurrence of a thermal lens effect phenomenon due to heat transmitted from the outside. And the measurement accuracy can be increased.

  The tip of the purge gas supply pipe can be arranged near the end of the measurement region.

  In this case, it is possible to prevent the sample gas introduced into the measurement region from flowing into the optical system member side, and it is possible to prevent the optical system member from being deteriorated or soiled. In addition, it is possible to prevent uneven temperature distribution near the end of the measurement region.

  A shielding plate that is provided at the tip of the purge gas supply pipe and shields the gap with the tubular member from the measurement region can be further provided.

  In this case, the sample gas does not flow into the gap between the tubular member and the purge gas supply pipe, and it is possible to suppress the occurrence of nonuniformity in the temperature distribution of the tubular member. Further, since the gap between the tubular member and the purge gas supply pipe is sealed by the shielding plate, the heat insulating effect by the gap is enhanced, and it is possible to prevent the temperature distribution from becoming uneven due to the influence of the outside air temperature.

  The tubular member can be disposed so as to intersect the flow path of the sample gas in the pipe in order to introduce the sample gas flowing in the pipe into the measurement region in the hollow interior. Furthermore, the optical system member includes a light emitting unit that is provided at the first end of the tubular member and emits measurement light to the measurement region, and a light receiving unit that receives the measurement light that has passed through the sample gas in the measurement region. A member and a second optical system member that is provided at the second end of the tubular member and configured by a reflector that reflects the irradiation light from the light emitting unit to the light receiving unit side can be included. In order to make the temperature distribution of the purge gas passing through the tip purge gas supply pipe and the tip purge gas supply pipe communicating with the gap between the purge gas supply pipe and the tubular member and having the tip positioned near the second optical system member uniform. And a stirring unit provided in a gap between the purge gas supply pipe and the tubular member. The purge gas is supplied to the vicinity of the second optical system member through the gap and the tip portion purge gas supply pipe.

  In this case, the purge gas supplied to one end of the measurement region via the purge gas supply pipe passes through the gap between the purge gas supply pipe and the tubular member, so that the inside of the purge gas supply pipe is insulated and is hardly affected by the outside air temperature. Furthermore, the purge gas that passes through the gap between the purge gas supply pipe and the tubular member is agitated by the agitating unit and has a uniform temperature distribution, so the heat transfer to the purge gas supply pipe is uniform, so the measurement The temperature of the purge gas existing in the optical path of the light is kept uniform, and the thermal lens effect phenomenon can be further suppressed.

  The gas analyzer can include a first unit and a second unit that are attached to opposing positions on the side wall of the pipe. In this case, the first unit and the second unit are respectively connected to a tubular member having a first end located inside or inside the flue and a second end located outside the flue, and a second end of the tubular member. An optical system member provided, and a purge gas supply pipe arranged with a gap between the inner wall surface of the tubular member and constituting a first purge gas path, wherein the gap between the tubular member and the purge gas supply pipe is the A second purge gas path for guiding the purge gas to one end may be configured, and a stirring unit for making the temperature distribution of the purge gas that passes through may be provided.

  In this case, the measurement accuracy can be improved by applying the configuration of the present invention to an open-pass gas analyzer. As an open-pass gas analyzer, for example, a light emitting unit and a light receiving unit that project and receive measurement light in a measurement region are provided in the first unit, and a reflector that reflects measurement light from the light emitting unit to the light receiving unit is a second unit. The present invention can be applied to a device such as that provided in the first unit, a light emitting portion provided in the first unit, and a light receiving portion provided in the second unit.

  The stirring unit may include one or a plurality of partition plates formed on the outer wall surface of the purge gas supply pipe in order to stir the purge gas passing through the gap between the tubular member and the purge gas supply pipe.

  As the partition plate, for example, one or a plurality of disc-shaped members for partitioning the gap into a plurality of regions are arranged apart from each other in the axial direction of the purge gas supply pipe, so that the gap can be divided into a plurality of regions. . In this case, when the purge gas flows into the region partitioned by the disk-shaped member, it passes through the gap between the disk-shaped member and the inner wall surface of the tubular member, and generates turbulent flow. Stir. Therefore, the purge gas passing through the gap between the tubular member and the purge gas supply pipe is agitated to make the temperature distribution uniform, and the heat transfer to the purge gas supply pipe becomes uniform, thereby suppressing the occurrence of the thermal lens effect phenomenon. can do.

  The stirring unit may include a spiral protrusion member that protrudes from the outer wall surface of the purge gas supply pipe. In this case, the purge gas passing through the gap between the tubular member and the purge gas supply pipe is guided and agitated so as to swivel along the spiral protrusion member on the outer surface of the purge gas supply pipe. As a result, the temperature distribution of the purge gas is made uniform, and the occurrence of the thermal lens effect phenomenon can be suppressed.

  In the gas analyzer according to the present invention, the temperature distribution on the optical path through which the measurement light passes can be made uniform, the occurrence of the thermal lens effect phenomenon can be prevented, and the measurement accuracy can be improved.

FIG. 1 is a perspective view of the gas analyzer of the first embodiment. FIG. 2 is a side view of the gas analyzer of the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of the gas analyzer of the first embodiment. FIG. 4 is an enlarged cross-sectional view of a main part of the gas analyzer of the second embodiment. FIG. 5 is an enlarged cross-sectional view of a main part of the gas analyzer of the second embodiment. FIG. 6 is a perspective view showing a main part of the gas analyzer of the third embodiment. FIG. 7 is a side view of the gas analyzer of the fourth embodiment. FIG. 8 is an explanatory view of a main part of a conventional gas analyzer.

(First embodiment)
FIG. 1 is a perspective view showing a configuration of a gas analyzer 1 according to a first embodiment of the present invention, and FIG. 2 is a side view thereof.

  The gas analyzer 1 includes a probe tube 11 (an example of a tubular member), an analysis unit 12, a flange 13, and a light guide tube 14.

  The analysis unit 12 (an example of a first optical system member) includes a light emitting unit 15, a light receiving unit 16, and a control unit 17.

  The light emitting unit 15 is a light source that emits a laser beam as measurement light to the gas to be measured through the light guide tube 14 and the probe tube 11, and is an infrared ray for irradiating light in a predetermined wavelength region with high straightness. A laser oscillation device can be used.

  The light receiving unit 16 is a light receiving element that receives measurement light incident through the measurement target gas in the flue.

  The control unit 17 controls the emission of the laser beam from the light emitting unit 15 and analyzes the component of the gas that is the measurement target based on the measurement light received by the light receiving unit 16.

  The analysis unit 12 is connected to the probe tube 11 via the light guide tube 14 and the flange 13.

  The probe tube 11 is formed in a hollow cylindrical shape, and is arranged so as to be orthogonal to the gas flow S in the flue 50 formed inside the pipe side wall 51.

  In the measurement region of the probe tube 11, an opening 18 for introducing gas into the probe tube 11 is provided on the downstream side of the gas flow S. In the illustrated example, a plurality of ribs 19 are provided in the opening 18 so as to maintain the strength of the probe tube 11. The shape of the opening 18 and the number of ribs 19 are not limited to the illustrated example.

  A reflector 20 (an example of a second optical system member) for reflecting measurement light emitted from the light emitting unit 15 of the analysis unit 12 is provided at the tip of the probe tube 11.

  The reflector 20 reflects the measurement light emitted from the light emitting unit 15 toward the light receiving unit 16 and can be configured by a corner cube prism.

  The gas analyzer 1 is attached to an attachment portion 52 of a pipe side wall 51 that constitutes the flue 50.

  The attaching part 52 can be comprised by the pipe 54 for installation attached to the opening 53 of the piping side wall 51, for example.

  The installation pipe 54 is a cylindrical member, and is fixed to the pipe side wall 51 by welding or screwing.

  Further, the installation pipe 54 is provided with a mounting flange 55 for fixing the gas analyzer 1, and the flange 13 of the gas analyzer 1 is welded or screwed to the mounting flange 55, whereby the gas analyzer is provided. 1 is indirectly fixed to the pipe side wall 51.

  When there is a gap 56 between the installation pipe 54 and the probe tube 11, the shielding plate 21 can be provided so that a part of the gas flow S flowing through the flue 50 does not flow into the gap 56.

  The probe tube 11 includes a first purge gas supply unit 22 and a second purge gas supply unit 23.

  The first purge gas supply unit 22 and the second purge gas supply unit 23 are provided at the distal end portion of the first optical system member and the probe tube 11 that are configured by the light emitting unit 15 and the light receiving unit 16 provided in the analysis unit 12, respectively. In order to protect the second optical system member composed of the reflector 20, purge gas is supplied into the probe tube 11.

  A flow rate control unit 48 is provided to supply the purge gas Pa to the first purge gas supply unit 22 and the second purge gas supply unit 23. The flow rate control unit 49 controls the flow rate by controlling the pressure with a regulator (not shown) and adjusting a needle valve (not shown) while looking at the flow meter (not shown).

  FIG. 3 is a cross-sectional view of one end side of the probe tube 11.

  A purge gas supply pipe 26 (an example of a purge gas supply pipe) is disposed with a gap 28 between the inner wall surfaces of the probe tube 11 and the light guide tube 14. The purge gas supply pipe 26 may be formed integrally with a portion disposed in the probe tube 11 and a portion disposed in the light guide tube 14, and in the flange 13 portion, the probe tube 11 side and the light guide tube 14 side. It may be divided into.

  The purge gas supply pipe 26 has a pipe shape having a hollow portion, and is provided with a connection port 30 to which the first purge gas supply unit 22 is connected. The purge gas supplied from the first purge gas supply unit 22 is supplied to the hollow portion of the purge gas supply pipe 26 through the connection port 30 and flows in the direction of the distal end portion 27.

  Further, in the hollow portion of the purge gas supply pipe 26, the measurement light emitted from the light emitting section 15 passes to the reflector 20 side, and the measurement light reflected by the reflector 20 and passed through the measurement region of the probe pipe 11 is on the light receiving section 16 side. An optical path passing through is formed.

  The purge gas supply pipe 26 has a substantially uniform inner diameter from the connection port 30 with the first purge gas supply part 22 to the tip part 27 located in the vicinity of the end of the measurement region of the probe pipe 11.

  A shield plate 29 that shields the gap 28 from the probe tube 11 is provided at the distal end portion 27 of the purge gas supply tube 26.

  A cutout hole 24 is provided on the upstream side located at one end of the measurement region of the probe tube 11. The gas flow S flows into the cutout hole 24.

  As shown in FIG. 3, the purge gas Pa and the gas flow S collide with each other at the distal end portion 27 of the purge gas supply pipe 26. The purge gas Pa is prevented from flowing into the measurement region side in the probe tube 11 by the gas flow S. As a result, a measurement error due to the purge gas does not occur in the measurement region. Further, the gas flow S is prevented from flowing into the analysis unit 12 side by the purge gas Pa. As a result, contamination and corrosion of the optical system such as the light emitting unit 15 and the light receiving unit 16 can be prevented. For this reason, the size of the notch hole 24 is larger than the inner diameter of the purge gas supply pipe 26 so that the gas flow S flowing into the probe pipe 11 through the notch hole 24 crosses the entire hollow section of the purge gas supply pipe 26. It is preferable to do.

  In this embodiment, the probe tube 11 is attached to the pipe side wall 51 by cantilever support on the flange 13 side. Therefore, the probe tube 11 may have a complicated structure in the attachment portion near the flange 13, the joint portion with the first purge gas supply unit 22, the joint portion with the analysis unit 12, and the like, and the inner diameter may vary. Even in such a case, the purge gas can be supplied in a laminar flow state to one end of the measurement region of the probe tube 11 via the purge gas supply tube 26, and uneven temperature distribution can be prevented. .

  The laminar flow state can be reliably obtained by the flow rate control by the flow rate control unit 49.

  Further, since the gap 28 between the probe tube 11 and the purge gas supply pipe 26 is sealed by the shielding plate 29, the temperature distribution due to the influence of the outside air temperature on the purge gas passing through the purge gas supply pipe 26 due to the heat insulation effect of this gap 28. Can be prevented from occurring.

  The purge gas supplied from the second purge gas supply unit 23 is supplied to the distal end portion of the probe tube 11 by a purge gas supply tube (not shown) disposed in the light guide tube 14 and the probe tube 11, and the probe tube 11 is introduced into the flue 50 together with the gas flow S that flows in from the cutout holes 25 and flows downstream. As a result, the purge gas can be prevented from flowing into the measurement region side in the probe tube 11, and a measurement error due to the purge gas does not occur in the measurement region. Further, the purge gas supplied from the second purge gas supply unit 23 can prevent the gas flow S flowing in from the cutout hole 25 from flowing into the reflector 20 side, and contamination and corrosion of the reflector 20 can be prevented. Also in this case, by making the size of the notch hole 25 larger than the diameter of the purge gas supply pipe, it is possible to prevent the purge gas flowing from the purge gas supply pipe from flowing into the measurement region.

As shown in FIG. 2, when the shielding plate 21 is provided on the probe tube 11, a part of the gas flow S does not flow into the gap 56 between the installation pipe 54 and the probe tube 11, and the temperature distribution is reduced. The effect of preventing non-uniformity can be further enhanced. The shape of the purge gas supply pipe 26 may be any configuration as long as it has an internal hollow through which measurement light can pass, and the cross section thereof may be polygonal, elliptical, or a composite shape thereof.
(Second Embodiment)
4 and 5 are cross-sectional views of main parts of a gas analyzer according to a second embodiment of the present invention.

  In the second embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the detailed description thereof will be omitted.

  Similarly to the first embodiment, the gas analyzer 1 in the second embodiment includes a probe tube 11, an analysis unit (not shown), a flange (not shown), and a light guide tube 14. In addition, the concentration of the sample gas is analyzed by projecting and receiving the measurement light by the light emitting unit and the light receiving unit attached to the analysis unit.

  A purge gas supply pipe 26 is disposed in the hollow portion of the probe pipe 11 with a gap from the inner wall surface of the probe pipe 11.

  The purge gas supply pipe 26 has a pipe shape having a hollow portion, and is provided with a connection port 30 to which the first purge gas supply unit 22 is connected. The purge gas supplied from the first purge gas supply unit 22 is supplied to the hollow portion of the purge gas supply pipe 26 through the connection port 30 and flows in the direction of the distal end portion 27.

  The probe tube 11 is provided with a connection port 31 to which the second purge gas supply unit 23 is connected. By connecting the second purge gas supply unit 23 to the connection port 31, the purge gas supplied from the second purge gas supply unit 23 can be introduced into the gap 28 between the probe tube 11 and the purge gas supply tube 26.

  A shield plate 29 that shields the gap 28 with the probe tube 11 is provided at the distal end portion 27 of the purge gas supply pipe 26, and an opening 32 is provided in the shield plate 29. Connected to the opening 32 of the shield plate 29 is a tip purge gas supply pipe 33 (an example of a tip purge gas supply pipe) for supplying purge gas to the vicinity of the reflector 20 provided at the tip of the probe tube 11.

  Notch holes 24 and 25 are provided on the upstream side located at both ends of the measurement region of the probe tube 11. The gas flow S flows into the cutout holes 24 and 25.

  As shown in FIG. 4, the purge gas Pa and the gas flow S collide with each other at the distal end portion 27 of the purge gas supply pipe 26. The purge gas Pa is prevented from flowing into the measurement region side in the probe tube 11 by the gas flow S. As a result, a measurement error due to the purge gas does not occur in the measurement region. Further, the gas flow S is prevented from flowing into the analysis unit 12 side by the purge gas Pa. As a result, contamination and corrosion of the optical system such as the light emitting unit 15 and the light receiving unit 16 can be prevented.

  As shown in FIG. 5, the purge gas Pa and the gas flow S collide with each other in the vicinity of the notch hole 25 and the tip of the tip purge gas supply pipe 33. The purge gas Pa supplied from the tip purge gas supply pipe 33 to the tip of the probe pipe 11 is introduced into the flue 50 together with the gas flow S flowing from the cutout hole 25 of the probe pipe 11 and flowing downstream. As a result, the purge gas Pa can be prevented from flowing into the measurement region side in the probe tube 11, and a measurement error due to the purge gas Pa does not occur in the measurement region. Further, the gas flow S is prevented from flowing into the reflector 20 side by the purge gas Pa. As a result, contamination and corrosion of the reflector 20 can be prevented.

  From this, the opening 32 and the tip purge gas supply pipe 33 of the shielding plate 29 are positioned eccentric from the center of the probe pipe 11 so as not to disturb the flow path of the sample gas introduced from the cutout holes 24 and 25. Provided. As shown in the figure, the tip purge gas supply pipe 33 is located downstream of the gas flow S in the probe pipe 11, so that the gas flow introduced from the cutout holes 24 and 25 collides with the tip purge gas supply pipe 33 and causes convection. Can be prevented. The tip of the tip purge gas supply pipe 33 is preferably located at the upstream side of the gas flow or at the center of the reflector in order to supply the purge gas on the surface of the reflector 20 and on the optical path of the measurement light.

  In the gap 28 between the probe tube 11 and the purge gas supply tube 26, a plurality of partition plates 34 (an example of a partition plate) are provided on the outer surface of the purge gas supply tube 26.

  When the probe tube 11 has a cylindrical shape, the partition plate 34 is configured by a disk having a diameter smaller than the inner diameter of the probe tube 11 so that a predetermined interval 35 is formed between the inner surface of the probe tube 11. Is done. Thus, the gap 28 between the probe tube 11 and the purge gas supply tube 26 has a structure in which a plurality of ring-shaped cavities 36 (an example of a stirring unit) partitioned by the partition plate 34 communicate with each other at an interval 35. The partition plate 34 is not limited to a disk shape, and may be any configuration as long as the gap 28 is partitioned into a plurality of cavities 36 and the cavities 36 communicate with each other at intervals 35. The shape can be appropriately changed according to the shape of the wall surface and the shape of the purge gas supply pipe 26.

  The purge gas supplied from the second purge gas supply unit 23 flows into the gap 28 through the connection port 31, and flows into the distal end purge gas supply pipe 33 through the opening 32 in the distal end portion 27 of the purge gas supply pipe 26.

  The purge gas flowing in the gap 28 narrows the flow path by passing through the interval 35 at the position of the partition plate 34, and suddenly widens when entering the cavity 36. A turbulent flow as shown by C is formed.

  Accordingly, the purge gas flowing in the gap 28 is agitated in the cavity 36, and passes along the outer periphery of the gap 28 along the inner wall surface of the probe tube 11 and along the outer wall surface of the purge gas supply pipe 26. Airflow will be mixed.

In this way, the purge gas supplied to the tip purge gas supply pipe 33 passes through the gap 28 and has a uniform temperature distribution. Therefore, the temperature difference between the purge gas passing through the tip purge gas supply pipe 33 arranged in the measurement region and the sample gas introduced into the probe pipe 11 is reduced, that is, the temperature distribution of the probe pipe 11 becomes uniform. As a result, the occurrence of the thermal lens effect phenomenon can be prevented.
(Third embodiment)
FIG. 6 is an enlarged perspective view of a main part of a gas analyzer according to a third embodiment of the present invention.

  In the third embodiment, the same reference numerals are given to the same elements as those in the first embodiment and the second embodiment, and the detailed description thereof will be omitted.

  As in the first embodiment, the gas analyzer 1 in the third embodiment includes a probe tube 11, an analysis unit (not shown), a flange (not shown), and a light guide tube (not shown). The sample gas concentration is analyzed by projecting and receiving the measurement light by the light emitting unit and the light receiving unit attached to the analysis unit.

  A purge gas supply pipe 26 is disposed in the hollow portion of the probe pipe 11 with a gap from the inner wall surface of the probe pipe 11.

  The purge gas supply pipe 26 has a pipe shape having a hollow portion, and guides the purge gas supplied from the first purge gas supply portion (not shown) to the hollow portion toward the distal end portion 27 side.

  A second purge gas supply unit (not shown) is connected to the probe tube 11, and the purge gas supplied from the second purge gas supply unit is introduced into the gap 28 between the probe tube 11 and the purge gas supply tube 26.

  A shield plate 29 that shields the gap 28 from the probe tube 11 is provided at the distal end portion 27 of the purge gas supply tube 26. The shielding plate 29 is provided with an opening 32, and a distal end purge gas supply pipe 33 that guides purge gas to the distal end side of the probe tube 11 is connected to the opening 32.

  Also in this case, the gas flow introduced from the notch hole 24 collides with the tip purge gas supply pipe 33 by making the tip purge gas supply pipe 33 downstream of the gas flow S in the probe pipe 11 as shown in the figure. Convection can be prevented.

  A spiral protrusion member 40 (an example of a partition plate) is provided on the outer wall surface of the purge gas supply pipe 26. The protrusion member 40 may have an outer periphery that is in contact with the inner wall surface of the probe tube 11, or may have a gap between the outer periphery and the inner wall surface of the probe tube 11. The projecting member 40 forms a spiral gas passage 41 (an example of an agitation unit) that rotates along the outer wall surface of the purge gas supply pipe 26 in the gap between the probe pipe 11 and the purge gas supply pipe 26.

  The purge gas supplied from the second purge gas supply unit is introduced into the gap between the probe tube 11 and the purge gas supply tube 26 and flows toward the opening 32. At this time, the purge gas travels spirally along the protrusion member 40 provided on the outer wall surface of the purge gas supply pipe 26 and reaches the opening 32 while being stirred in the gas passage path 41.

In this way, the purge gas supplied to the tip purge gas supply pipe 33 passes through the gap 28 and has a uniform temperature distribution. Therefore, the temperature difference between the purge gas passing through the tip purge gas supply pipe 33 arranged in the measurement region and the sample gas introduced into the probe pipe 11 is reduced, and thereby the temperature distribution of the probe pipe 11 becomes uniform. Therefore, the occurrence of the thermal lens effect phenomenon can be prevented.
(Fourth embodiment)
FIG. 7 is a cross-sectional side view of the gas analyzer 100 according to the fourth embodiment of the present invention.

  The gas analyzer 100 includes a first unit 110 (an example of a first unit) and a second unit 130 (an example of a second unit) that are disposed at opposing positions on a pipe side wall 151.

  The first unit 110 includes an analysis unit 111, a first light guide tube 115, a first flange 116, and a first sleeve 117 (an example of a tubular member).

  The analysis unit 111 includes a light emitting unit 112, a light receiving unit 113, and a control unit 114.

  The light emitting unit 112 is a light source that emits a laser beam as measurement light to the gas to be measured through the first light guide tube 115 and the first sleeve 117, and irradiates light in a predetermined wavelength region with high straightness. For example, an infrared laser oscillation device.

  The light receiving unit 113 is a light receiving element that receives measurement light incident through the measurement target gas in the flue.

  The control unit 114 controls the emission of the laser beam from the light emitting unit 112 and performs component analysis of the gas to be measured based on the measurement light received by the light receiving unit 113.

  The analysis unit 111 is connected to the first sleeve 117 via the first light guide tube 115 and the first flange 116.

  A first purge gas supply pipe 120 is disposed inside the first light guide pipe 115 and the first sleeve 117 of the first unit 110 with a gap 118 therebetween. In the first purge gas supply pipe 120, a portion disposed in the first sleeve 117 and a portion disposed in the first light guide tube 115 may be integrally formed, and the first sleeve is formed at the first flange 116 portion. It may be divided into the 117 side and the first light guide tube 115 side.

  The first purge gas supply pipe 120 has a pipe shape having a hollow part, and is provided with a connection port 122 to which the first purge gas supply part 121 is connected. The purge gas supplied from the first purge gas supply part 121 is supplied to the hollow part of the first purge gas supply pipe 120 via the connection port 122 and flows in the direction of the tip part.

  Thus, the hollow part of the first purge gas supply pipe 120 provides a guide path for the purge gas supplied from the first purge gas supply part 121 and also provides a path for the measurement light emitted from the light emitting part 112.

  The first purge gas supply pipe 120 has a substantially uniform inner diameter from the connection port 122 to the tip end portion 129 located in the vicinity of the inner peripheral surface of the pipe side wall 151.

  Thus, the purge gas passing through the hollow portion of the first purge gas supply pipe 120 can be made into a laminar flow, and the occurrence of the thermal lens effect phenomenon based on the nonuniform temperature distribution can be prevented.

  The first light guide tube 115 is provided with a connection port 124 to which the second purge gas supply unit 123 is connected. By connecting the second purge gas supply unit 123 to the connection port 124, the purge gas supplied from the second purge gas supply unit 123 can be introduced into the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120. .

  A flow rate control unit 148 is provided to supply the purge gas Pa to the first purge gas supply unit 121 and the second purge gas supply unit 123. The flow rate control unit 148 controls the flow rate by controlling the pressure with a regulator (not shown) and adjusting a needle valve (not shown) while looking at the flow meter (not shown).

  In the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120, a plurality of partition plates 125 (an example of a partition plate) are provided on the outer surface of the first purge gas supply pipe 120.

  When the first sleeve 117 is cylindrical, the partition plate 125 is a circle having a diameter smaller than the inner diameter of the first sleeve 117 so that a predetermined interval 126 is formed between the first sleeve 117 and the inner wall surface of the first sleeve 117. Consists of plates. Thus, the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120 has a structure in which a plurality of ring-shaped cavities 127 (an example of a stirring unit) partitioned by the partition plate 125 communicate with each other at an interval 126. Become. The partition plate 125 is not limited to a disk shape, and may be any configuration as long as it partitions the gap 118 into a plurality of cavities 127 and allows the cavities 127 to communicate with each other at intervals 126. The shape can be appropriately changed according to the shape of the inner wall surface and the shape of the first purge gas supply pipe 120.

  The purge gas supplied from the second purge gas supply unit 123 flows into the gap 118 through the connection port 124 and is guided into the flue 150 through the plurality of cavities 127.

  The purge gas flowing in the gap 118 narrows the flow path by passing through the interval 126 at the position of the partition plate 125, and the flow path suddenly widens when entering the cavity 127, so that the arrows A, B, A turbulent flow as shown by C is formed.

  Therefore, the purge gas flowing in the gap 118 is agitated in the cavity 127, and the airflow passing along the inner wall surface of the first sleeve 117 and the airflow passing along the outer wall surface of the first purge gas supply pipe 120 are mixed. Will fit.

  In this way, the temperature distribution of the purge gas flowing in the gap 118 becomes uniform, and the purge gas flowing in the first purge gas supply pipe 120 is prevented from being influenced by the non-uniform temperature of the outside air. The temperature distribution in can be made uniform. As a result, the occurrence of the thermal lens effect phenomenon can be prevented and the measurement accuracy can be improved.

  In the example shown in FIG. 7, the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120 is open toward the flue 150 at the tip portion, but a shielding plate is provided at the tip portion. Is also possible. In that case, the purge gas that prevents the sample gas from reaching the optical system member by providing an opening in the shielding plate is located upstream of the distal end portion of the first purge gas supply pipe 120 and is effective. Can be flushed.

  Further, by providing such a shielding plate at the distal end portion 129 of the first purge gas supply pipe 120, the distal end portion 129 of the first purge gas supply pipe 120 can be fixed to the first sleeve 117, and the first purge gas supply pipe It is possible to improve the measurement accuracy by preventing the tip portion 129 of 120 from vibrating.

  The first attachment portion 152 includes, for example, a first attachment flange 154 provided in the opening 153 of the pipe side wall 151.

  A shielding plate 128 is attached so as to shield the gap 155 between the opening 153 of the first attachment portion 152 and the first sleeve 117.

  The shielding plate 128 is provided in the vicinity of the inner surface 156 of the pipe side wall 151. As described above, since the shielding plate 128 is provided on the flue 150 side, the sample gas can be prevented from flowing into the gap 155.

  The shielding plate 128 is a disk-shaped member fixed to the outer peripheral surface of the first sleeve 117, and the outer peripheral edge is close to or in contact with the inner peripheral surface of the opening 153. In the case of proximity, the gap is preferably small from the viewpoint of blocking the sample gas. In the case of contact, the gap 155 is shielded, and the sample gas blocking effect is enhanced.

  In the illustrated example, an example in which one shielding plate 119 is attached to the first sleeve 117 is shown. However, a plurality of shielding plates can be arranged with a gap in the axial direction of the first sleeve 117. In this case, the sample gas is less likely to flow into the gap 155.

  The second unit 130 includes a reflector 131, a second light guide tube 132, a second flange 133, and a second sleeve 134 (an example of a tubular member).

  The reflector 131 reflects the measurement light emitted from the light emitting unit 112 toward the light receiving unit 113 and can be configured by a corner cube prism.

  The reflector 131 is connected to the second sleeve 134 via the second light guide tube 132 and the second flange 133.

  A second purge gas supply pipe 136 is disposed inside the second light guide tube 132 and the second sleeve 134 of the second unit 130 with a gap 135 therebetween. In the second purge gas supply pipe 136, a portion disposed in the second sleeve 134 and a portion disposed in the second light guide tube 134 may be formed integrally, and the second sleeve is formed at the second flange 133 portion. It may be divided into the 134 side and the second light guide tube 132 side.

  The second purge gas supply pipe 136 has a pipe shape having a hollow portion, and is provided with a connection port 138 to which the third purge gas supply portion 137 is connected. The purge gas supplied from the third purge gas supply part 137 is supplied to the hollow part of the second purge gas supply pipe 136 via the connection port 138 and flows in the direction of the tip part.

  As described above, the hollow portion of the second purge gas supply pipe 136 provides a guide path for the purge gas supplied from the third purge gas supply section 137, and the path of the measurement light emitted from the light emitting section 112 and reflected by the reflector 131. I will provide a.

  The second purge gas supply pipe 136 has a substantially uniform inner diameter from the connection port 138 to the tip portion 145 located in the vicinity of the inner peripheral surface of the pipe side wall 151.

  As a result, the purge gas passing through the hollow portion of the second purge gas supply pipe 136 can be made into a laminar flow, and the occurrence of the thermal lens effect phenomenon based on the uneven temperature distribution can be prevented.

  The second light guide tube 132 is provided with a connection port 140 to which the fourth purge gas supply unit 139 is connected. By connecting the fourth purge gas supply unit 139 to the connection port 140, the purge gas supplied from the fourth purge gas supply unit 139 can be introduced into the gap 135 between the second sleeve 134 and the second purge gas supply pipe 136. .

  A flow rate control unit 149 is provided to supply the purge gas Pa to the third purge gas supply unit 137 and the fourth purge gas supply unit 139. The flow rate control unit 149 controls the flow rate by controlling the pressure with a regulator (not shown) and adjusting a needle valve (not shown) while looking at the flow meter (not shown).

  In the gap 135 between the second sleeve 134 and the second purge gas supply pipe 136, a plurality of partition plates 141 are provided on the outer surface of the second purge gas supply pipe 136.

  When the second sleeve 134 has a cylindrical shape, the partition plate 141 is a circle having a diameter smaller than the inner diameter of the second sleeve 134 so that a predetermined interval 142 is formed between the second sleeve 134 and the inner wall surface of the second sleeve 134. Consists of plates. As a result, the gap 135 between the second sleeve 134 and the second purge gas supply pipe 136 has a structure in which a plurality of ring-shaped cavities 143 partitioned by the partition plate 141 communicate with each other at intervals 142. The partition plate 141 is not limited to a disc shape, and may be any configuration as long as the gap 135 is partitioned into a plurality of cavities 143 and the cavities 143 communicate with each other at intervals 142. The shape can be appropriately changed according to the shape of the inner wall surface and the shape of the second purge gas supply pipe 136.

  The purge gas supplied from the fourth purge gas supply unit 139 flows into the gap 135 through the connection port 140 and is guided into the flue 150 through the plurality of cavities 143.

  The purge gas flowing in the gap 135 passes through the interval 142 at the position of the partition plate 141, so that the flow path becomes narrow, and when entering the cavity portion 143, the flow path suddenly widens. Turbulence is formed.

  Therefore, the purge gas flowing in the gap 135 is agitated in the cavity portion 143, and the airflow passing along the inner wall surface of the second sleeve 134 and the airflow passing along the outer wall surface of the second purge gas supply pipe 136 are mixed. Will fit.

  In this way, the temperature distribution of the purge gas flowing in the gap 135 becomes uniform, the purge gas flowing in the second purge gas supply pipe 136 is prevented from being influenced by outside air, and the temperature distribution on the optical path of the measurement light is reduced. It can be made uniform. As a result, the occurrence of the thermal lens effect phenomenon can be prevented and the measurement accuracy can be improved.

  In the example shown in FIG. 7, the second sleeve 134 also has a configuration in which a gap 135 between the second purge gas supply pipe 136 and the second purge gas supply pipe 136 is open toward the flue 150. It is also possible. In that case, the purge gas that prevents the sample gas from reaching the optical system member by providing an opening in the shielding plate is located upstream of the distal end portion of the second purge gas supply pipe 136 and is effective. Can be flushed.

  Further, by providing such a shielding plate at the distal end 145 of the second purge gas supply pipe 136, the distal end 145 of the second purge gas supply pipe 136 can be fixed to the second sleeve 134, and the second purge gas supply pipe It is possible to increase the measurement accuracy by preventing the tip portion 145 of 136 from vibrating.

  The 2nd attachment part 160 is provided with the 2nd attachment flange 162 provided in opening 161 of piping side wall 151, for example.

  The shielding plate 164 is attached so as to shield the gap 163 between the opening 161 of the second attachment portion 160 and the second sleeve 134.

  The shielding plate 164 is provided in the vicinity of the inner surface 156 of the pipe side wall 151. Thus, since the shielding plate 164 is provided on the side of the flue 150, the sample gas can be prevented from flowing into the gap 163.

  The shielding plate 164 is a disk-shaped member fixed to the outer peripheral surface of the second sleeve 134, and the outer peripheral edge is close to or in contact with the inner peripheral surface of the opening 161. In the case of proximity, the gap is preferably small from the viewpoint of blocking the sample gas. Further, in the case of contact, the gap 163 is shielded, and the sample gas blocking effect is enhanced.

  In the illustrated example, an example in which one shielding plate 164 is attached to the second sleeve 134 is shown, but a plurality of shielding plates can be arranged with a gap in the axial direction of the second sleeve 134, In this case, the sample gas is less likely to flow into the gap 163.

  In the fourth embodiment, when the first unit 110 including an optical system member that performs light projection and reception and the second unit 130 including an optical member including a reflector are attached at positions facing the pipe side wall 151, the purge gas Prevents the sample gas from reaching the optical system member to prevent the optical system member from being contaminated, and makes the temperature distribution of the purge gas located on the optical path of the measurement light uniform to prevent the occurrence of the thermal lens effect phenomenon. ing.

  The tips of the first sleeve 117 and the second sleeve 134 may be configured to protrude into the flue 150 from the inner surface 156 of the pipe side wall 151. For example, when the length of the measurement region is set shorter than the inner diameter of the pipe side wall 151, the distance between the distal end portion of the first sleeve 117 and the distal end portion of the second sleeve 134 matches the length of the measurement region. The lengths of the first sleeve 117 and the second sleeve 134 are set.

  In this case, the front end portion 129 of the first purge gas supply pipe 120 and the front end portion 145 of the second purge gas supply pipe 136 are positioned at the same positions as the front ends of the first sleeve 117 and the second sleeve 134, respectively.

  Instead of the disc-shaped partition plate 125 and the partition plate 141, spiral ridge members can be provided on the outer wall surfaces of the first purge gas supply pipe 120 and the second purge gas supply pipe 134.

  The ridge member may have the same configuration as that of the third embodiment, and may be in contact with the inner wall surfaces of the first sleeve 117 and the second sleeve 134. The structure with a clearance gap between wall surfaces may be sufficient.

  By this projecting member, a spiral gas passage is formed and supplied to the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120 and the gap 135 between the second sleeve 134 and the second purge gas supply pipe 136. The purge gas is introduced into the flue 150 while being stirred in the gas passage.

  Thus, the temperature of the purge gas that has passed through the gap 118 between the first sleeve 117 and the first purge gas supply pipe 120 and the gap 135 between the second sleeve 134 and the second purge gas supply pipe 136 becomes uniform, and the first purge gas supply pipe 120 is made uniform. In addition, the temperature distribution of the purge gas passing through the inside of the second purge gas supply pipe 136 becomes uniform.

  Therefore, the temperature distribution inside the first purge gas supply pipe 120 and the second purge gas supply pipe 136 constituting the optical path of the measurement light becomes uniform, thereby preventing the thermal lens effect phenomenon from occurring and improving the measurement accuracy. It becomes possible to make it.

  Even in the case where the light projecting unit and the light receiving unit are mounted at positions facing each other across the pipe side wall, the purge gas supply pipe can be configured in a double pipe structure.

(Modification A)
The purge gas supply pipe 26 includes a first purge gas supply pipe that includes only the path of the measurement light emitted from the light emitting unit 15, and a second purge gas that includes only the path of the measurement light that passes through the measurement region and is received by the light receiving unit 16. The supply pipe can be independent.

  In this case, it is necessary to separately provide means for supplying purge gas to the first purge gas supply pipe and the second purge gas supply pipe.

In this case, the pipe diameter for supplying the purge gas can be reduced, and the flow rate of the purge gas for protecting the optical system member can be reduced.
(Modification B)
The purge gas supply pipe 26 may be a pipe having an elliptical cross section.

  In this case, the flow path diameter of the purge gas can be reduced according to the arrangement state of the light emitting unit 15 and the light receiving unit 16, and the flow rate of the purge gas for protecting the optical system member can be reduced.

  In addition, the purge gas supply pipe 26 can have various cross-sectional shapes, and can have a triangle, a polygon including a quadrangle, and a combination of a circle, an ellipse, and a polygon.

  In this case, the design freedom based on the shape of the probe tube 11 and other members can be increased.

(Modification C)
In the embodiment described above, a double tube structure of the probe tube 11 and the purge gas supply tube 26 is proposed, but one or more tube members are inserted between the probe tube 11 and the purge gas supply tube 26 to multiplex them. It can also be a tube structure.

  In this case, the temperature of the purge gas flowing in the purge gas supply pipe 26 is kept uniform by the heat insulation function by the gap formed between the pipe members, thereby preventing the occurrence of the thermal lens effect phenomenon.

(Modification D)
In the said embodiment, although the partition plate 34 and the protrusion member 40 were illustrated as a stirring part, another shape may be sufficient.

(Modification E)
In the above embodiment, the inner diameter of the purge gas supply pipe 26 is uniform along the flow path direction. However, the purge gas supply pipe may have portions having different inner diameters.

(Modification F)
In each embodiment, the gas analyzer using a laser beam as the measurement light has been disclosed. However, the present invention can be applied to a gas analyzer using other light sources.
(Other embodiments)
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.

  For example, the probe type, gas type, partition plate position, number of partition plates, partition plate shape, partition plate size, ridge member shape, and ridge member pitch can be combined. Can be configured.

  The configuration of the present invention can also be applied to the case where the light projecting unit and the light receiving unit are attached at positions facing each other across the pipe side wall. For example, it can be set as the structure provided with one light emission part of the 1st unit 110 of 4th Embodiment, and the 2nd unit 130, and a light-receiving part in the other.

  Even in such a case, by providing a double tube structure in each of the unit including the light emitting unit and the unit including the light receiving unit, the sample gas can be prevented from reaching the light emitting unit and the light receiving unit, and the temperature of the purge gas can be reduced. By making the distribution uniform, it is possible to suppress measurement light fluctuation based on the occurrence of the thermal lens effect phenomenon and to improve measurement accuracy.

  The present invention can be widely applied to a gas analyzer including a gas analysis probe disposed in a pipe in order to analyze the concentration of a predetermined component in a sample gas flowing in the pipe.

DESCRIPTION OF SYMBOLS 1 Gas analyzer 11 Probe pipe 12 Analysis unit 26 Purge gas supply pipe 35 Partition plate 36 Cavity part 40 Projection member 41 Gas passage route

Claims (7)

A tubular member that projects measurement light onto a predetermined measurement region of the sample gas flowing in the pipe and / or forms an optical path for receiving measurement light from the measurement region;
An optical system member that projects measurement light onto the sample gas in the measurement region and / or receives measurement light from the measurement region;
A hollow portion including a purge gas flow path for supplying a purge gas to a region between the optical system member and the measurement region and an optical path of the measurement light, and the gap is formed between the inner wall surface of the tubular member and the gap A purge gas supply pipe disposed inside the tubular member;
A gas analyzer comprising:   The gas analyzer according to claim 1, wherein the purge gas flowing through the hollow portion of the purge gas supply pipe is a laminar flow.   The gas analyzer according to claim 1 or 2, wherein a tip of the purge gas supply pipe is disposed in the vicinity of an end of the measurement region.   The gas analyzer according to any one of claims 1 to 3, further comprising a shielding plate provided at a distal end of the purge gas supply pipe and shielding the gap with the tubular member from the measurement region. The gap between the purge gas supply pipe and the tubular member constitutes a second purge gas flow path for supplying purge gas to a region between the optical system member and the measurement region,
The stirrer provided in the gap between the purge gas supply pipe and the tubular member for stirring the purge gas passing through the second purge gas flow path is further provided according to any one of claims 1 to 4. Gas analyzer. The tubular member is disposed so as to intersect the flow path of the sample gas in the pipe in order to introduce the sample gas flowing in the pipe into the measurement region in the hollow interior,
The optical system member includes a light emitting unit that is provided at a first end of a tubular member and emits the measurement light to the measurement region, and a light receiving unit that receives the measurement light that has passed through the sample gas in the measurement region. A system member, and a second optical system member configured by a reflector that is provided at a second end of the tubular member and reflects light emitted from the light emitting unit toward the light receiving unit,
A tip purge gas supply pipe communicating with the gap between the purge gas supply pipe and the tubular member and having a tip positioned near the second optical system member;
The gas analyzer according to claim 5, further comprising: a purge gas supplied to the vicinity of the second optical system member through the second purge gas flow path and the tip purge gas supply pipe.   The stirrer includes one or more partition plates provided on an outer wall surface of the purge gas supply pipe to stir purge gas passing through a gap between the tubular member and the purge gas supply pipe. The gas analyzer described in 1.

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