JP2009080017A - Flow cell for multiplex reflection cell type gas analysis system, multiplex reflection cell type gas analysis system, and adjustment method of mirror-to-mirror distance of flow cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow cell for a multiple reflection cell type gas analysis system, capable of easily compensating an effect of variation in curvature radius of Miller with no increase in cost, a multiple reflection cell type gas analysis system, and an adjustment method of a mirror-to-mirror distance of the flow cell. <P>SOLUTION: The flow cell includes: a cylindrical cell body 5 having a sample gas inlet 15 and a sample gas outlet 16; a first mirror 2a located at a first termination section of the cell body 5, having a tunnel 4 through which incident light and emission light pass; a second mirror 6 located at a second termination section of the cell body 5, having a second mirror surface opposed a first mirror surface of the first mirror 2a; and spacer insertion units (11b, 12, 17b, 18) for inserting a spacer 13 between the second termination section and the second mirror 6 to adjust the distance between the first mirror 2a and the second mirror 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multi-reflection cell type gas analysis system used for measuring a concentration of a trace component such as an impurity gas in a gas, and in particular, to adjust a distance between mirrors of a flow cell for a multi-reflection cell type gas analysis system before shipment in a factory. Regarding technology.

As a gas analysis system, a Herriott type is well known as a multiple reflection cell that is the basis of a multiple reflection cell type gas analysis system. (For example, refer nonpatent literature 1.). The Elliott gas cell has two spherical mirrors or parabolic mirrors facing the cylindrical cell body, and light is incident through a small hole provided on the peripheral edge of one of the mirrors. Then, the light beam is again taken out from the incident light at an angle different from that of the incident light. In addition,
In order for light to emerge from the same hole as the incident light after multiple reflections, the relationship between the number of reflections within the device, the distance between the mirrors, and the radius of curvature or focal length of the mirror (for aspherical mirrors) is strictly Must be accurate. Although the distance between the mirrors is determined by the processing accuracy of the cell body, the simple structure of the cell body can generally be used to produce the workpiece, and an accuracy of tolerance ± 0.1 mm can be easily obtained. However, the radius of curvature or focal length of the mirror depends on the characteristics of the curved surface structure, the properties such as the ductility of the metal, and the characteristics of the polishing process to maintain the performance as a mirror (high reflectivity, low scattered light). Since processing errors at the product level are inevitable, the accuracy is very difficult to obtain, and there is a problem that it is practically impossible to achieve the design value in industrial production.

The adjustment mechanism of the curvature radius of the mirror of the flow cell for the multiple reflection cell type gas analysis system will be described below with reference to Table 1. In Table 1, in the flow cell for the multi-reflection cell type gas analysis system used, the accuracy error at the product level of the curvature radius of the opposing mirror is equal (the error of the curvature radius of the two opposing mirrors is equal). The positional deviation between the incident light and the outgoing light in the incident hole (outgoing hole) is shown with respect to the error of the radius of curvature relative to the reference dimension (in the case of a flow cell designed with a mirror distance of 260 mm and a mirror curvature radius of 275 mm). ). The emitted light is assumed to be obtained when the laser beam incident from the center of the incident hole as incident light is emitted from the emission hole after repeated multiple reflections 30 times between the opposing mirrors. The “error” of the radius of curvature is the difference between the actual measurement value of the product and the design reference value due to the reduction in processing accuracy caused in mirror processing.

As is apparent from Table 1, the error of the curvature radius of the mirror is −2.0 mm, −1.0 mm, 0 mm, +1.0 mm, and +2.0 mm, and the incident light and the outgoing light at the incident hole (outgoing hole) are different. The distances are +3.1 mm, +1.6 mm, 0 mm, −1.6 and −3.0 mm, respectively. From this, it can be seen that as the error in the radius of curvature increases, the distance (positional deviation) between the incident light and the outgoing light in the incident hole (outgoing hole) also increases. If the curvature of the mirror causes an error from the design reference value, the output light after multiple reflections shifts the optical axis, so that the stray light is scattered by the walls of the entrance and exit holes, or does not exit from the hole, This results in greatly degrading the performance of the multiple reflection cell gas analysis system in photometry.

  To solve this problem, it is possible to correct the influence of the error by changing the distance between the mirrors in the radius of curvature of the mirror or the error of the focal length based on the calculation result of the ray tracing (for example, Patent Documents). 1).

However, in the method described in Patent Document 1, it is necessary to change the distance between mirrors by using a gasket for vacuum sealing and a gasket for adjusting the distance between mirrors as one set. There is a problem that the annealing product is necessary, the production is difficult, and the cost increases.
D. R. Herriott, H.C. Kogelnik, R.A. Kompfer, "Appl. Opt.", 3rd edition, 1964, p. 523 JP 2006-58009 A

  In view of the above problems, the present invention provides a flow cell for a multi-reflection cell type gas analysis system, which can easily compensate for the influence of variations in the radius of curvature of the mirror at the time of mirror manufacture without increasing the cost. It is an object of the present invention to provide a method for adjusting the distance between mirrors of a multiple reflection cell type gas analysis system and a flow cell used.

  The first aspect of the present invention includes (a) a cylindrical cell body having a sample gas inlet and a sample gas outlet, (b) a first mirror provided at a first terminal end of the cell body, and (c) A second mirror having a second mirror surface provided at a second terminal portion of the cell body facing the first terminal portion and facing the first mirror surface of the first mirror; and (d) a second terminal portion and a second mirror. And a spacer insertion means for adjusting the distance between the first and second mirrors by inserting a spacer between the second terminal portion and the second mirror. It is a flow cell for use.

  The second aspect of the present invention is: (a) a cylindrical cell body having a sample gas inlet and a sample gas outlet, a first mirror provided at the first end of the cell body, and a cell body facing the first end And a flow cell having a second mirror having a second mirror surface opposite to the first mirror surface of the first mirror, and (b) connected to the flow cell to electrically transmit optical information from the flow cell. The present invention relates to a multiple reflection cell type gas analysis system including an analyzer for converting into a signal. Here, for the multiple reflection cell type gas analysis system according to the second aspect, the distance between the first and second mirrors is adjusted by selecting the thickness of the spacer between the second terminal portion and the second mirror. Spacer insertion means is provided.

  According to a third aspect of the present invention, a cylindrical cell body having a sample gas inlet and a sample gas outlet, a first mirror provided at a first end of the cell body, and a second of the cell body facing the first end are provided. The present invention relates to a method for adjusting a distance between mirrors of a flow cell for a multi-reflection cell type gas analysis system including a second mirror having a second mirror surface provided at a terminal portion and facing a first mirror surface of a first mirror. Here, the adjustment method of the distance between the mirrors of the flow cell for the multiple reflection cell type gas analysis system according to the third aspect is as follows: (a) When the curvature radii of the first mirror and the second mirror are both the minimum allowable dimension. In contrast, designing the length of the cell body and assembling the flow cell without a spacer, and (b) introducing incident light into the flow cell and measuring the light intensity of the outgoing light output from the flow cell Inserting a plurality of spacers having different thicknesses between the second terminal portion and the second mirror, selecting a spacer having a thickness that gives the maximum light intensity, and adjusting a distance between the first and second mirrors; It is characterized by including. Here, the “minimum allowable dimension” is a case where the dimensional tolerance of the radius of curvature of the first mirror and the second mirror has a negative maximum value (maximum negative tolerance).

  According to a fourth aspect of the present invention, a cylindrical cell body having a sample gas inlet portion and a sample gas outlet portion, a first mirror provided at a first end portion of the cell body, and a second cell body facing the first end portion. The present invention relates to a method for adjusting a distance between mirrors of a flow cell for a multi-reflection cell type gas analysis system including a second mirror having a second mirror surface provided at a terminal portion and facing a first mirror surface of a first mirror. Here, the adjustment method of the distance between the mirrors of the flow cell for the multiple reflection cell type gas analysis system according to the fourth aspect is as follows: (a) When the curvature radii of the first mirror and the second mirror are both the minimum allowable dimension. Designing the length of the cell body for assembling the flow cell without a spacer; (b) introducing incident light into the flow cell and measuring the light intensity of the emitted light output from the flow cell; (C) a step of confirming whether the measured light intensity has reached a specified value; and (d) if the measured light intensity has not reached the specified value, place a first spacer between the second terminal end of the cell body and the second mirror. Inserting and reassembling the flow cell.

  According to a fifth aspect of the present invention, a cylindrical cell body having a sample gas inlet and a sample gas outlet, a first mirror provided at a first terminal end of the cell body, and a second cell body facing the first terminal end. The present invention relates to a method for adjusting a distance between mirrors of a flow cell for a multi-reflection cell type gas analysis system including a second mirror having a second mirror surface provided at a terminal portion and facing a first mirror surface of a first mirror. Here, the method for adjusting the distance between the mirrors of the flow cell for the multiple reflection cell type gas analysis system according to the fifth aspect includes (a) measuring the radii of curvature of the first mirror and the second mirror, respectively. ) A step of determining a spacer having an optimum thickness based on the measurement result; and (c) inserting the determined spacer between the second terminal portion and the second mirror, and between the first and second mirrors. Adjusting the distance.

  According to the present invention, a flow cell for a multi-reflection cell type gas analysis system capable of easily compensating for the influence of the variation in the radius of curvature of the mirror at the time of manufacturing the mirror without increasing the cost, and multiple reflection using the flow cell. A cell type gas analysis system and a method for adjusting a distance between mirrors of a flow cell can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings. Further, the following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

(Multiple reflection cell gas analysis system)
The multiple reflection cell type gas analysis system according to the embodiment of the present invention shown in FIG. 1 includes a flow cell 9a and an analyzer 10a. The flow cell 9a includes a cylindrical cell body 5 having a sample gas inlet portion 15 and a sample gas outlet portion 16, and a tunnel portion 4 provided at a first end portion of the cell body 5 and through which incident light and outgoing light pass. 1 mirror 2a, and the 2nd mirror 6 which is provided in the 2nd termination part of cell body 5 facing the 1st termination part, and has the 2nd mirror surface which counters the 1st mirror surface of the 1st mirror 2a. And between the 2nd termination | terminus part and the 2nd mirror 6, the spacer insertion means (11b, 12, 17b, which adjusts the distance between the 1st mirror 2a and the 2nd mirror 6 by selection of the thickness of the spacer 13) 18).

  The cell body 5 includes a first flange 19 joined to the first mirror 2a at the first end portion and a second flange 20 joined to the second mirror 6 at the second end portion. A first O-ring groove 17a is provided in the first mirror 2a, and a first O-ring 11a is inserted into the first O-ring groove 17a, and the first mirror 2a and the first flange 19 are connected via the first O-ring 11a. Connected with vacuum confidentiality. The spacer inserting means (11b, 12, 17b, 18) includes an O-ring groove (third O-ring groove) 18 provided in the second flange 20 and an O-ring groove (second O-ring) provided in the second mirror 6. Groove) 17b, a third O-ring 12 inserted into the third O-ring groove 18, and a second O-ring 11b inserted into the second O-ring groove 17b. The spacer insertion means (11b, 12, 17b, 18) is configured such that the spacer 13 is sandwiched between the second O ring 11b and the third O ring 12, and the second mirror 6 is formed by the second O ring 11b and the third O ring 12. And the second flange 20 are connected while maintaining vacuum secrecy.

  A window plate 3 is attached to the inside of the first mirror 2a fixed to the first terminal portion of the cell body 5, and the tunnel portion 4 is separated into the analyzer 10a side and the cell body 5 side. In the first mirror 2a, the first O-ring 11a is closer to the center side of the first mirror 2a than the plurality of holes into which the fixing screws 14 are inserted, on the joint surface side with the first flange 19 provided in the cell body 5 at the first terminal portion. Is mounted in the first O-ring groove 17a.

  The second O-ring 11b that forms a part of the spacer insertion means (11b, 12, 17b, 18) has a plurality of holes through which the fixing screws 14 are inserted in the second mirror 6 on the joint surface side with the second terminal portion. Is also mounted in a second O-ring groove 17 b provided on the center side of the second mirror 6. In the second flange 20 provided in the cell terminal 5 at the second terminal end, the third O-ring 12 is closer to the center side of the second terminal end than the plurality of holes into which the fixing screws 14 are inserted and to the outer diameter of the second O-ring groove 17b. The third O-ring groove 18 having a large inner diameter is mounted. That is, as illustrated in FIG. 1, the position of the third O-ring groove 18 provided in the second flange 20 and the position of the second O-ring groove 17 b provided in the second mirror 6 are determined by the second flange 20. Different in radial direction. However, FIG. 1 is merely an example, and conversely, the third O-ring 12 may be mounted in a third O-ring groove 18 having an outer diameter smaller than the inner diameter of the second O-ring groove 17b.

  As shown in FIG. 1, the flow cell 9a according to the first embodiment includes a first mirror 2a, a second mirror 6, a spacer 13, and a cell body 5 by a first O ring 11a, a second O ring 11b, and a third O ring 12. The formed space is sealed while maintaining vacuum confidentiality, and the gas and fluid are introduced / extracted from / into the cell body 5 only by the sample gas entering / exiting the sample gas inlet 15 and the sample gas outlet 16.

  In FIG. 1, the first mirror 2 a and the second mirror 6 are illustrated in the case where the flange portion and the mirror portion are integrated, respectively, but the first mirror 2 a and the second mirror 6 are divided into a flange portion and a mirror portion, respectively. It is also possible to have a configuration. Further, the first mirror 2 a is fixed to the first flange 19 at the first end portion of the cell body 5 by a fixing screw 14. The fixing screw 14 is screwed from the cell body 5 side to the first mirror 2a side at a plurality of locations such as 4 to 8 locations, and fixes the cell body 5 and the first mirror 2a. The second mirror 6 is fixed to the second flange 20 by the fixing screw 14 at the second terminal end via the spacer 13 while facing the first mirror 2a. The fixing screws 14 are screwed into the spacer 13 and the second mirror 6 side from the cell body 5 side at a plurality of locations, and fix the cell body 5, the spacer 13 and the second mirror 6. FIG. 1 illustrates the case where the first mirror 2a and the second mirror 6 are internally threaded, but through holes are formed in the first mirror 2a and the second mirror 6, and the fixing screw 14 is fixed with a nut. Various modifications, such as form, are possible. Further, the first mirror 2a may be fixed to the first flange 19 in a vacuum coupling manner without using the fixing screw 14 while keeping the vacuum secret. In this case, both the first mirror 2a and the first flange 19 may have a flat flange seal portion and a taper on the opposite side. When a clamp is fitted into this taper portion and the thumbscrew is tightened, a force is generated toward the center of the flange, and the O-ring is crushed and sealed. At this time, a center ring that serves as a guide for the O-ring may be provided.

  As materials for the first mirror 2a, the second mirror 6, the cell body 5, the spacer 13 and the fixing screw 14, for example, stainless steel (SUS) can be used in consideration of corrosion resistance. The first O-ring 11a, the second O-ring 11b, and the third O-ring 12 are made of, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), silicone rubber (VMQ), fluoro rubber (FKM), natural rubber, or the like. Synthetic rubber can be used.

  As shown in FIG. 1, the analyzer 10 a includes a light source 1, a light source mirror 54 that reflects the light beam emitted from the light source 1 so as to be introduced into the flow cell, a detector mirror 55 that reflects the light beam returned from the flow cell, A detector 7 that detects a light beam reflected by the detector mirror 55 and photoelectrically converts optical information into electrical information, and stores the purge gas inlet 51 to which the purge gas is supplied and the purge gas purged. And a light source chamber 50a provided with a purge gas discharge port 52. The light beam emitted from the light source 1 passes through the window plate 3 and enters the inside of the cell body 5 from the tunnel portion 4 provided in the first mirror 2a. The incident light beam reaches the second mirror 6. The light beam is reflected several times to 100 times, so-called multiple reflection, between the first mirror 2 a and the second mirror 6 constituting the reflection surface of the cell body 5. Subsequently, the light beam after multiple reflection passes through the tunnel portion 4 and the window plate 3 in the reverse order of the incident light and then exits from the cell body 5 and is detected at an angle slightly different from the incident light. Detected by vessel 7.

  A semiconductor laser or the like can be used for the light source 1. The reason for using a semiconductor laser is that in a lamp light source such as a halogen lamp, the divergence of a light beam increases during multiple reflection between the first mirror 2a and the second mirror 6, and a sufficient amount of light cannot be extracted from the exit hole. It is. The light source mirror 54 introduces a light beam composed of laser light emitted from the light source 1 into the flow cell. The detector mirror 55 reflects the returned light beam to the detector 7 after multiple reflection in the flow cell 9a. The detector 7 detects the emitted light after multiple reflection in the cell body 5 reflected by the detector mirror 55, and photoelectrically converts the light signal to an electric signal. As the detector 7, for example, a photoelectric detector having a photoelectric conversion element such as a silicon (Si) diode and an indium gallium arsenide (InGaAs) diode can be used.

Nitrogen gas (N ₂ ) is reduced to a predetermined pressure and supplied to the purge gas inlet 51 provided in the light source chamber 50a. Further, the purge gas discharge port 52 discharges the purged nitrogen gas. Regarding the nitrogen gas purge inside the light source chamber 50a, a simple dripping method may be used, or a pressure applying valve may be provided on the purge gas discharge port 52 side. The preamplifier 56 is connected to the detector 7 and amplifies the electric signal of the light beam photoelectrically converted by the detector 7. The hermetic seal type connector 53 takes out the electric signal of the light beam amplified by the preamplifier 56 to the outside of the light source chamber 50a, and the taken out electric signal is subjected to signal processing such as a personal computer through the signal cable, for example, gas concentration. Is sent to an information processing apparatus that displays the spectrum of.

(Example structure of spacer insertion means)
2A to 2C show the structure of the spacer insertion means (11b, 12, 17b, 18) according to the embodiment of the present invention provided between the second terminal portion and the second mirror 6. FIG. It is sectional drawing which shows an example. FIG. 2A is a sectional view of the spacer insertion means (11b, 12, 17b, 18) of the flow cell 9a assembled without the spacer 13. FIG. As shown in FIG. 2A, the position of the third O-ring groove 18 provided in the second flange 20 and the position of the second O-ring groove 17b provided in the second mirror 6 are determined by the second flange 20. Therefore, even if the flow cell 9a is assembled without the spacer 13, the vacuum secrecy between the second flange 20 and the second mirror 6 can be achieved. In order to achieve a vacuum seal between the second flange 20 and the second mirror 6 when the flow cell 9a is assembled without the spacer 13, the position of the third O-ring groove 18 in the radial direction of the second flange 20 It is preferable to design so that the position of the second O-ring groove 17b does not overlap. In addition, in the radial direction of the second flange 20, the position of the third O-ring groove 18 and the position of the second O-ring groove 17b are configured so as to overlap with each other, so that the third O-ring groove 18 and the second O-ring groove 17b are thick. A modification in which an O-ring is inserted or a common thick square packing is inserted is also possible. If the length of the cell body 5 is designed for the case where both the first mirror 2a and the second mirror 6 have the minimum allowable radius of curvature, if the first mirror 2a and the second mirror 6 are actually In both cases, if the radius of curvature is the minimum allowable dimension, the optimum distance between the first mirror 2a and the second mirror 6 is the case without the spacer 13 as shown in FIG. Here, the “minimum allowable dimension” is a case where the dimensional tolerance of the radius of curvature of the first mirror and the second mirror has a negative maximum value (maximum value of the negative tolerance). If the radius of curvature of either the first mirror 2a or the second mirror 6 has a radius of curvature larger than the minimum allowable dimension, the distance between the first mirror 2a and the second mirror 6 needs to be adjusted. Therefore, adjustment using the spacers 13a and 13b as shown in FIG. 2 (b) or (c) is required.

  FIG. 2B is a cross-sectional view of spacer insertion means (11b, 12, 17b, 18) in which a spacer thinner than the spacer 13 shown in FIG. 1 is inserted between the second terminal portion and the second mirror 6. The distance between the first mirror 2a and the second mirror 6 in FIG. 2B is longer than the distance in FIG. 2A and shorter than the distance in FIG.

  FIG. 2C is a cross-sectional view of spacer insertion means (11b, 12, 17b, 18) in which a spacer thicker than the spacer 13 shown in FIG. 1 is inserted between the second terminal portion and the second mirror 6. The distance between the 1st mirror 2a and the 2nd mirror 6 in FIG.2 (c) is longer than the distance in each of FIG.2 (a), FIG.2 (b), and FIG.

In the case of a flow cell having a mirror distance of 260 mm, a mirror radius of curvature of 275 mm, and multiple reflections of 30 times illustrated in Table 1, the error of the mirror radius of curvature is changed by changing the distance between the mirrors. Table 2 shows how much can be corrected. Similar to Table 1, Table 2 assumes that the errors in the curvature radii of the first and second mirrors facing each other are equal.

  As shown in Table 2, when the distance between the mirrors is changed by -2.0 mm when the curvature radius error is -2.0 mm, the positional deviation of the emitted light is reduced to -0.3 mm. Therefore, if the dimensional tolerance of the first mirror 2a and the second mirror 6 is ± 2.0 mm, the distance between the first mirror 2a and the second mirror 6 of ± 2.0 mm may be adjusted, and the dimensional tolerance is If it is ± 1.0 mm, the distance between the first mirror 2 a and the second mirror 6 of ± 1.0 mm may be adjusted. However, since the length of the cell body 5 of the flow cell 9a cannot be shortened, the length of the cell body 5 is set in advance when both the first mirror 2a and the second mirror 6 have the minimum allowable radius of curvature. The distance between the mirrors is optimized by designing and increasing the length of the cell body 5. That is, when considering the dimensional tolerance in manufacturing the first mirror 2a and the second mirror 6, the length of the cell body 5 may be reduced when the radius of curvature of both the first mirror 2a and the second mirror 6 is the minimum allowable dimension. Since the shortest case, the spacer insertion means (11b, 12, 17b, 18) inserts a spacer between the second terminal end of the cell body 5 and the second mirror as required, thereby The distance between the mirror 2a and the second mirror 6 can be adjusted.

As described above, the radii of curvature described in Tables 1 and 2 are when the first mirror 2a and the second mirror 6 both exhibit the same curvature error. In actual production, the variation in the curvature of the mirror is various, the first mirror 2a is a plus error, the second mirror 6 is a minus error; the first mirror 2a is a plus error, and the second mirror 6 is a plus error. The first mirror 2a has a minus error, the second mirror 6 has a minus error, the first mirror 2a has a minus error, the second mirror 6 has a plus error, and so on. Even assuming average curvature error = +1 mm:
(A) The first mirror 2a and the second mirror 6 are both +1 mm;
(B) the first mirror 2a is +0.5 mm and the second mirror 6 is +1.5 mm;
(C) The first mirror 2a is +2.0 mm and the second mirror 6 is ± 0 mm;
(D) the first mirror 2a is +3.0 mm and the second mirror 6 is −1 mm;
The situation is complicated. According to an empirical rule, the first mirror 2a and the second mirror 6 in (a) both have a curvature error of +1 mm, and the first mirror 2a in (b) is +0.5 mm, and the second mirror 6 is +1. There is almost no difference in positional deviation in the case of a curvature error of 5 mm. However, when the first mirror 2a of (c) is +2.0 mm and the second mirror 6 has a curvature error of ± 0 mm, the positional deviation is slightly larger than the cases of (a) and (b) (extremely No difference). In the case of the combination of (3) +3 mm and −1 mm, the positional deviation becomes more remarkable. Therefore, when the average curvature error is equal, the positional deviation error tends to increase as the absolute deviation between the first mirror 2a and the second mirror 6 increases.

(First method for adjusting the distance between mirrors)
Next, a method for adjusting the inter-mirror distance of the flow cell 9a for the multiple reflection cell gas analysis system according to the embodiment of the present invention will be described. As described above, in the method for adjusting the inter-mirror distance according to the embodiment of the present invention, the length of the cell body 5 is previously set so that the first mirror 2a and the second mirror 6 both have the minimum allowable radius of curvature. If designed for the case (when the dimensional tolerance is the maximum value of the negative tolerance), the length of the cell body 5 can be optimized by increasing the length of the cell body 5. Therefore, the spacers may be prepared as a set of a plurality of sets, for example, in a combination of increasing thickness in order of 0.3 mm step, 0.4 mm step, 0.5 mm step,... . At this time, if the data as shown in Table 2 is acquired in advance, the necessary adjustment thickness can be known according to the manufacturing tolerance of the first mirror 2a and the second mirror 6, so the first mirror 2a In addition, a plurality of spacers may be prepared until the radius of curvature of both the second mirror 6 is the maximum allowable dimension (when the dimensional tolerance is the maximum plus tolerance).

  (A) First, the second terminal portion and the second mirror 6 are joined, and the flow cell 9a is assembled without the spacer 13 as shown in FIG. Then, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the intensity of the emitted light emitted from the tunnel portion 4 is detected after the light beam is multiple-reflected inside the flow cell 9a. It is measured by the device 7 and it is confirmed whether the intensity of the emitted light measured by the detector 7 has reached a specified value.

  (B) When the intensity of the emitted light has reached the specified value, the adjustment of the inter-mirror distance is finished. If the specified value is not reached, it means that at least one of the first mirror 2a and the second mirror 6 is manufactured with a radius of curvature larger than the minimum allowable dimension, and as shown in FIG. As the thinnest spacer among the plurality of prepared spacers, the first spacer 13a is inserted between the second terminal portion 5 and the second mirror 6 to reassemble the flow cell 9a. Thereby, the distance between the 1st mirror 2a and the 2nd mirror 6 becomes larger than the distance (initial value) between the 1st mirror 2a and the 2nd mirror 6 shown to Fig.2 (a).

  (C) After inserting the first spacer 13a, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the light flux is multiple-reflected inside the flow cell 9a. The intensity of the emitted light emitted from the sensor is measured by the detector 7, and it is confirmed whether the measured intensity of the emitted light has reached a specified value. When the specified value is reached, a manufacturing error in the radius of curvature of the first mirror 2 a and the second mirror 6 causes the first spacer 13 a to be inserted between the second terminal end of the cell body 5 and the second mirror 6. Therefore, the first spacer 13a is selected as the optimum spacer for correcting the curvature radii of the first mirror 2a and the second mirror 6.

(D) If the intensity of the emitted light measured by the detector 7 does not reach the specified value, the manufacturing error of the radius of curvature is not compensated, so as shown in FIG. A second spacer 13b thicker than the first spacer 13a is inserted between the second terminal portion and the second mirror 6, and the flow cell 9a is reassembled. After inserting the second spacer 13b, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the light beam is emitted from the tunnel portion 4 after being multiple-reflected inside the flow cell 9a. The intensity of the emitted light is measured by the detector 7 and it is confirmed whether the measured intensity of the emitted light has reached a specified value.
(E) When the specified value is reached, the manufacturing error in the radius of curvature of the first mirror 2a and the second mirror 6 causes the second spacer 13b between the second terminal end of the cell body 5 and the second mirror 6. The second spacer 13b is selected as the optimum spacer for correcting the curvature radii of the first mirror 2a and the second mirror 6 because it is determined that it has been corrected (compensated) by insertion.

  (F) If the intensity of the emitted light measured by the detector 7 does not reach the specified value, the manufacturing error in the radius of curvature has not been compensated for, so the second end portion of the cell body 5 and the second mirror 6 In the meantime, the third spacer, which is thicker than the second spacer 13b, is inserted, and the operation is repeated until the intensity of the emitted light reaches a specified value. If both the first mirror 2a and the second mirror 6 have the maximum radius of curvature (when the dimensional tolerance is the maximum plus tolerance), the intensity of the emitted light is the specified value even if the spacer is inserted. If not, both the first mirror 2a and the second mirror 6 have a radius of curvature that deviates from the dimensional tolerance, so that at least one of the first mirror 2a and the second mirror 6 is replaced, Repeat steps.

  Thus, according to the first method for adjusting the distance between the mirrors according to the embodiment of the present invention, the flow cell 9a is inserted by sequentially inserting the thick spacer between the second terminal portion and the second mirror 6. Can be adjusted to an optimum length suitable for manufacturing errors in the radius of curvature of the first mirror 2a and the second mirror 6 used in the flow cell 9a.

(Second method for adjusting the distance between mirrors)
The first adjustment method of the distance between the mirrors described above is an example, and the adjustment of the distance between the mirrors according to the embodiment of the present invention can be performed by various other adjustment methods of the distance between the mirrors including this modification. Of course, the method is feasible. That is, in the first method for adjusting the distance between the mirrors, the light intensity of the emitted light output from the flow cell is measured and it is confirmed whether the measured light intensity reaches a specified value. Without use, while measuring the light intensity of the emitted light output from the flow cell, a plurality of spacers having different thicknesses are sequentially inserted between the second terminal portion and the second mirror to obtain the maximum light intensity. A spacer may be selected to adjust the distance between the first and second mirrors.

  Also in the second method for adjusting the distance between mirrors according to the embodiment of the present invention, the length of the cell body 5 is previously set when the radius of curvature of the first mirror 2a and the second mirror 6 is the minimum allowable dimension ( Of course, it is designed for a case where the dimensional tolerance is the maximum minus tolerance. Then, as in the first method for adjusting the distance between the mirrors, data as shown in Table 2 is acquired in advance until both the first mirror 2a and the second mirror 6 have the radius of curvature of the maximum allowable dimension. Prepare a plurality of spacers with the required thickness.

  (A) First, the second terminal portion and the second mirror 6 are joined, and the flow cell 9a is assembled without the spacer 13 as shown in FIG. Then, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the intensity of the emitted light emitted from the tunnel portion 4 is detected after the light beam is multiple-reflected inside the flow cell 9a. The intensity of the emitted light measured by the detector 7 and recorded by the detector 7 is recorded ("recording" does not necessarily have to be recorded on a medium such as paper, but may be stored in the human brain).

  (B) Next, as shown in FIG. 2B, the first spacer 13a is used as the thinnest spacer among the plurality of spacers prepared between the second terminal portion of the cell body 5 and the second mirror 6. Insert and reassemble flow cell 9a. Thereby, the distance between the 1st mirror 2a and the 2nd mirror 6 becomes larger than the distance (initial value) between the 1st mirror 2a and the 2nd mirror 6 shown to Fig.2 (a). Then, after inserting the first spacer 13a, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel part 4, and after the light beam is multiple-reflected inside the flow cell 9a, from the tunnel part 4 The intensity of the emitted light that is emitted is measured by the detector 7, and the measured intensity of the emitted light is recorded and compared with the intensity of the emitted light when assembled without the spacer 13. If the intensity of the emitted light is lower than the intensity of the emitted light when assembled without the spacer 13, the intensity of the emitted light is maximized when assembled without the spacer 13. Return to (optimal state) and finish the adjustment of the distance between mirrors.

(C) If the intensity of the emitted light is higher than the intensity of the emitted light when assembled without the spacers 13, there is a possibility that manufacturing errors in the radii of curvature of the first mirror 2a and the second mirror 6 are not compensated. 2 (c), a second spacer 13b thicker than the first spacer 13a is inserted between the second terminal portion of the cell body 5 and the second mirror 6, so that the flow cell 9a Reassemble. After inserting the second spacer 13b, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the light beam is emitted from the tunnel portion 4 after being multiple-reflected inside the flow cell 9a. The intensity of the emitted light is measured by the detector 7, the measured intensity of the emitted light is recorded, and compared with the intensity of the emitted light when assembled by inserting the first spacer 13a. If the intensity of the emitted light is lower than the intensity of the emitted light when the first spacer 13a is inserted and assembled, the intensity of the emitted light is the maximum when the first spacer 13a is inserted and assembled. Then, the first spacer 13a is reinserted (returned to the optimum state), and the adjustment of the inter-mirror distance is finished.
(D) If the intensity of the emitted light is lower than the intensity of the emitted light when the first spacer 13a is inserted and assembled, the manufacturing error of the radius of curvature may not be compensated for, so the cell body 5 A third spacer, which is thicker than the second spacer 13b, is inserted between the second terminal portion and the second mirror 6 to reassemble the flow cell 9a. After inserting the third spacer, the incident light emitted from the light source 1 is introduced into the flow cell 9a through the tunnel portion 4, and the light beam is emitted from the tunnel portion 4 after being multiple-reflected inside the flow cell 9a. The intensity of the emitted light is measured by the detector 7, and the measured intensity of the emitted light is recorded and compared with the intensity of the emitted light when assembled by inserting the second spacer 13b. If the intensity of the emitted light is lower than the intensity of the emitted light when the second spacer 13b is inserted and assembled, the intensity of the emitted light is the maximum when the second spacer 13b is inserted and assembled. Then, the second spacer 13b is reinserted (returned to the optimum state), and the adjustment of the distance between the mirrors is completed.
(E) If the intensity of the emitted light is lower than the intensity of the emitted light when the second spacer 13b is inserted and assembled, the manufacturing error of the radius of curvature may not be compensated for, so the cell body 5 A fourth spacer, which is thicker than the third spacer, is inserted between the second terminal portion and the second mirror 6 to reassemble the flow cell 9a. After inserting the fourth spacer, check whether the output light intensity was the maximum when the third spacer was inserted and assembled. Repeat until is discovered. Even if the spacer is inserted until both the first mirror 2a and the second mirror 6 have the maximum radius of curvature (when the dimensional tolerance is the maximum plus tolerance), the output light intensity is maximized. If the thickness of the spacer is not found, the curvature radius of both the first mirror 2a and the second mirror 6 deviates from the dimensional tolerance, so that at least one of the first mirror 2a and the second mirror 6 is replaced. Then repeat the above steps.

  In this way, even by the second method for adjusting the distance between the mirrors according to the embodiment of the present invention, the emitted light intensity can be increased while sequentially inserting a thick spacer between the second terminal portion and the second mirror 6. The thickness of the spacer to be maximized is determined, and the length of the flow cell 9a is easily set to an optimum length that matches the manufacturing error of the radius of curvature of the first mirror 2a and the second mirror 6 used in the flow cell 9a. And it becomes possible to adjust by simple operation.

  As described above, according to the adjustment method of the distance between mirrors of the flow cell 9a according to the embodiment of the present invention, as described in the adjustment method of the distance between the first and second mirrors, the second termination portion and the second mirror 6 are used. By inserting a spacer in between, the length of the flow cell 9a, that is, the distance between the first mirror 2a and the second mirror 6 is adjusted, and an error in manufacturing the radius of curvature of the first mirror 2a and the second mirror 6 Can be corrected easily and without any extra cost.

(Other embodiments)
As described above, the present invention has been described according to the above-described embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

    For example, in the first method for adjusting the distance between the mirrors, the light intensity of the emitted light output from the flow cell is measured, whether or not the measured light intensity reaches a specified value, and the distance between the second mirrors is confirmed. In the distance adjustment method, the light intensity of the outgoing light output from the flow cell was measured, and a spacer having a thickness that gives the maximum light intensity was selected. The distance adjustment method between the first mirror and the second mirror You may use combining the adjustment method of distance. That is, the light intensity of the emitted light output from the flow cell is measured to confirm whether the measured light intensity has reached a specified value. Rather than ending and adjusting the distance between the mirrors, after that, as with the second method for adjusting the distance between the mirrors, a thicker spacer is inserted and the light intensity of the emitted light output from the flow cell is measured. Then, after confirming whether the thickness provides the maximum light intensity, the adjustment of the inter-mirror distance may be terminated.

  Further, if the curvatures of the first mirror 2b and the second mirror 6 are obtained in advance with another three-dimensional surface shape analyzer, and the spacer having the optimum thickness determined by empirical rules is determined based on the value, The distance between the mirrors can be adjusted quickly.

  Further, as shown in FIG. 3, if the flow cell 9b includes the first mirror 2b having the incident light side tunnel portion 4a and the outgoing light side tunnel portion 4b, the degree of freedom in mechanical design is improved. The incident light side tunnel portion 4a is an incident light side window plate 3a that is separated on the light source 1 side and the cell body 5 side, and the outgoing light side tunnel portion 4b is an outgoing light side tunnel portion 4b, and the detector 7 side and the cell body 5 are separated. The outgoing light side window plates 3b separated from each other are arranged. Unlike the light source chamber 50a of the multiple reflection cell type gas analysis system in the first embodiment shown in FIG. 1, the light source chamber 50b constituting the analyzer 10b has a hole for receiving incident light from the light source 1, and a detection Holes through which outgoing light detected by the vessel 7 is emitted are provided at different positions.

  Also, by heating to a certain temperature, adhesion of water molecules to the surfaces of the first mirror 2b and the second mirror 6 can be prevented, the response time can be prolonged due to the influence of adhering water vapor, In order to solve the problem of accumulation of hydroxide or the like caused by the reaction, the first mirror 2a, the first mirror 2b, and the second mirror 6 in which a cartridge heater or the like is embedded may be used.

  Further, the spacer 13 disposed between the second mirror 6 and the cell body 5 may be disposed between the first mirror 2a and the cell body 5, and between the first mirror 2b and the cell body 5, or both. May be.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a general-view figure of the multiple reflection cell type gas analysis system concerning an embodiment of the invention. It is typical sectional drawing for demonstrating adjustment of the distance between mirrors by inserting the spacer of the flow cell which concerns on embodiment of this invention. It is a typical sectional view of a multiple reflection cell type gas analysis system concerning other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source 2a, 2b ... 1st mirror 3 ... Window plate 3a ... Incident light side window plate 3b ... Outgoing light side window plate 4 ... Tunnel part 4a ... Incident light side tunnel part 4b ... Outgoing light side tunnel part 5 ... Cell body 6 2nd mirror 7 ... Detector 9a, 9b ... Flow cell 10a, 10b ... Analyzer 11a ... 1st O-ring 11b ... 2nd O-ring 12 ... 3rd O-ring 13 ... Spacer 13a ... 1st spacer 13b ... 2nd spacer 14 DESCRIPTION OF SYMBOLS Fixing screw 15 ... Sample gas inlet part 16 ... Sample gas outlet part 17a ... 1st O-ring groove 17b ... 2nd O-ring groove 18 ... 3rd O-ring groove 19 ... 1st flange 20 ... 2nd flange 50a, 50b ... Light source chamber 51 ... Purge gas inlet 52 ... Purge gas outlet 53 ... Hermetically sealed connector 54 ... Light source mirror 55 ... Detector mirror 56 ... Preamplifier

Claims (8)

A cylindrical cell body having a sample gas inlet and a sample gas outlet;
A first mirror provided at a first terminal end of the cell body;
A second mirror provided at a second end portion of the cell body facing the first end portion and having a second mirror surface facing the first mirror surface of the first mirror;
The distance between the first and second mirrors is adjusted by inserting a spacer between the second termination part and the second mirror. The spacer is inserted between the second termination part and the second mirror. A flow cell for a multiple reflection cell type gas analysis system, comprising: a spacer insertion means. The cell body includes a first flange joined to the first mirror at the first terminal end, and a second flange joined to the second mirror at the second terminal end,
A position of an O-ring groove provided on the second flange and forming part of the spacer insertion means; and a position of an O-ring groove provided on the second mirror and forming another part of the spacer insertion means. The flow cell according to claim 1, wherein the flow cell differs in a radial direction of the second flange. A cylindrical cell body having a sample gas inlet portion and a sample gas outlet portion, a first mirror provided at the first end portion of the cell body, provided at a second end portion of the cell body facing the first end portion; A flow cell having a second mirror having a second mirror surface opposite the first mirror surface of the first mirror;
An analyzer coupled to the flow cell and converting optical information from the flow cell into an electrical signal, wherein the first terminal is selected between the second terminal and the second mirror by selecting a thickness of the spacer. And a spacer insertion means for adjusting the distance between the second mirror and the second reflection cell type gas analysis system. The cell body includes a first flange joined to the first mirror at the first terminal end, and a second flange joined to the second mirror at the second terminal end,
A position of an O-ring groove provided on the second flange and forming part of the spacer insertion means; and a position of an O-ring groove provided on the second mirror and forming another part of the spacer insertion means. The multi-reflection cell type gas analysis system according to claim 3, wherein the gas analysis system differs in a radial direction of the second flange. A cylindrical cell body having a sample gas inlet portion and a sample gas outlet portion, a first mirror provided at the first end portion of the cell body, provided at a second end portion of the cell body facing the first end portion; A method for adjusting a distance between mirrors of a flow cell for a multiple reflection cell type gas analysis system comprising a second mirror having a second mirror surface facing a first mirror surface of the first mirror,
Designing the length of the cell body for the case where the radius of curvature of the first mirror and the second mirror both have a minimum allowable dimension, and assembling the flow cell without a spacer;
While introducing incident light into the flow cell and measuring the light intensity of the emitted light output from the flow cell, a plurality of spacers having different thicknesses are sequentially disposed between the second terminal portion and the second mirror. And a step of selecting a spacer having a thickness that gives the maximum light intensity and adjusting a distance between the first and second mirrors. A cylindrical cell body having a sample gas inlet portion and a sample gas outlet portion, a first mirror provided at the first end portion of the cell body, provided at a second end portion of the cell body facing the first end portion; A method for adjusting a distance between mirrors of a flow cell for a multiple reflection cell type gas analysis system comprising a second mirror having a second mirror surface facing a first mirror surface of the first mirror,
Designing the length of the cell body for the case where the radius of curvature of the first mirror and the second mirror both have a minimum allowable dimension, and assembling the flow cell without a spacer;
Introducing incident light into the flow cell and measuring the light intensity of the emitted light output from the flow cell;
Checking whether the light intensity measured without the spacers reaches a specified value;
A step of adjusting a distance between the first and second mirrors by inserting a first spacer between the second terminal portion and the second mirror if the predetermined value is not reached; A method for adjusting a distance between mirrors of a flow cell as a feature. After inserting the first spacer, introducing incident light into the flow cell and measuring the light intensity of the emitted light output from the flow cell;
Confirming whether the light intensity measured by inserting the first spacer has reached the specified value;
If the specified value is not reached, a second spacer thicker than the first spacer is inserted between the second terminal portion and the second mirror to adjust the distance between the first and second mirrors. The method for adjusting the inter-mirror distance according to claim 6, further comprising: A cylindrical cell body having a sample gas inlet portion and a sample gas outlet portion, a first mirror provided at the first end portion of the cell body, provided at a second end portion of the cell body facing the first end portion; A method for adjusting a distance between mirrors of a flow cell for a multiple reflection cell type gas analysis system comprising a second mirror having a second mirror surface facing a first mirror surface of the first mirror,
Measuring the radii of curvature of the first mirror and the second mirror, respectively;
Determining a spacer having an optimum thickness based on the measurement results;
Inserting the determined spacer between the second termination and the second mirror to adjust the distance between the first and second mirrors. Adjustment method.

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