JPS6069537A - Infrared ray gas analyzer - Google Patents

Abstract

PURPOSE:To improve a measuring precision, responsiveness and maintenance of the titled analyzer, and to make a continuous measurement for a gaseous sample containing dust as well by cleaning automatically the surfaces of a main body part side of an infrared transmission window at a position apart from a measuring cell as blocking plates move. CONSTITUTION:Blades 291, 292 exist respectively at a main body part 15 side of closing plates 221, 222, and are provided radially at an opposite side to the part 15 side against shafts 231, 232. Widths L1, L2 of respective top end parts of the blades are set equally to those of annulations of the infrared transmission windows 191, 192, and said end parts are in contact with surfaces of the windows 191, 192. With revolutions of the plates 221, 222, the parts of the windows 191, 192, to which dusts contained in the gaseous sample in the main body part are allowed to adhere when opening ends of the part 15 are closed, are brought to positions of blades 291, 292. The adhering dusts are removed automatically by these blades as the plates 221, 222 revolve.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to an infrared gas analyzer that continuously measures the concentration of a predetermined component gas in a mixed gas by utilizing the infrared edge absorption characteristics of gas, and particularly to a mixed gas analyzer. The present invention relates to an infrared gas analyzer that automatically cleans an infrared transmitting window constituting a sample cell through which sample gas is introduced.

[Prior art and its problems]

FIG. 1 is a block diagram of a conventional non-dispersive flooded beam type infrared gas analyzer. In this analyzer, infrared rays emitted from a light source section 1 are distributed by a distribution pipe 2 into a measurement light beam 3 and a reference light beam 4 having the same light intensity, the measurement light m3 is incident on a measurement cell 5, and the reference light beam 4 is incident on a reference cell 6. is incident on the The measurement cell 5 is configured so that a sample gas is introduced through sample gas conduits 7 and 8, and the reference cell 6 is filled with a gas that does not have infrared absorption characteristics, such as nitrogen. When a measurement component gas having infrared absorption characteristics is introduced into the measurement cell 5, infrared absorption in the characteristic absorption wavelength band of the gas corresponding to the concentration of the gas occurs in the measurement light beam 3 incident on the measurement cell 5. No infrared absorption occurs in the reference light beam 4 incident on the reference beam 4 . 9 is a detector having a first detection chamber 10 and a second detection chamber 11, a flow rate detection element 12 is provided at the boundary between the two chambers, and a chamber is filled with measurement component gas at a predetermined concentration. The measurement light beam 3 and the reference light beam 4 that have passed through the cell 5 and the reference cell 6 enter the first detection chamber 10 and the second detection chamber 11, respectively. The detection element 12 is configured such that the gas filled in the detection chamber 10°11 can flow through the detection element □
Ru. Therefore, the light beam 3. incident on the detection chamber 10.11.
The wavelength range specific to the gas is absorbed by the filled gas, and the temperature of the filled gas rises and expands. A motor 13 is connected between the measuring cell 5 and the reference cell 6 and the detector 9.
A sector 14 is provided, which is activated by a sector 14, by means of which the light beams 3.4 incident on the detector 9 are interrupted simultaneously and periodically. This result detection chamber 10.1
The expansion of the filling gas at step 1 is repeated periodically.

The gas analyzer shown in Figure 1 is configured as described above, so if the sample gas contains the component gas to be measured and the temperature is below ℃,
Since there is no infrared absorption in the measurement cell 5 and reference cell 6, the amount of infrared light incident on the detection chamber 10.11 is equal;
The temperature rise and expansion of the filling gas in the compartments are also equal, so that no gas flow is generated between the two chambers through the 4ψ output element 12. However, if the sample gas contains the measurement component gas, the above-mentioned infrared absorption will occur in the measurement cell 5, so the amount of light incident on the detection chamber 10 will be smaller than the amount of light incident on the detection chamber 11.
As a result, there is a difference in the thickness of the gas expansion generated in both side chambers, and therefore a gas flow passing through the detection cord 12 is generated between these chambers. This gas flow has a thickness that corresponds to the concentration of the measurement component gas contained in the sample gas, and the detection element 1
2 outputs a signal corresponding to the thickness of this gas flow, so the concentration of the gas component to be measured in the sample gas is summed up by this signal. In the above description, 12 is used as a flow rate detection element, but a pressure detection element may be used instead of this element. In FIG. 1, 15 is a cylindrical main body, and 16 and 17 are provided so as to airtightly close both ends of the main body 15; for example, an infrared transmitting window made of calcium fluoride, and the measurement cell 5 is in this case the main body. The reference cell 6 is constructed in the same manner as the measuring cell 5 except for the configuration of the conduit 16.17. There is. The light rays 3.4 can therefore each be transmitted through a cell 5.6.

Figure 2 is a block diagram of a known non-dispersive single-beam external beam gas analyzer.The main difference from Figure 1 is that a reference cell is not provided, and this analyzer also has a light source. Part 1
The infrared rays emitted from the first detection chamber 10 enter the first detection chamber 10, and the amount of the incident infrared light is detected by the detection element 12. 1st
In the analyzer shown in the figure, the difference in the amount of light incident on the detection chamber 10. Become.

In the analyzer of FIGS. 1 and 2, the sample gas is introduced into the measuring cell 5 as described above. Therefore, if this sample gas contains dust such as carbon particles and ash, this dust will adhere to the infrared transmitting windows 16 and 17 and cause the first
The amount of infrared light incident on the detection chamber 10 changes, and as a result, the output signal of the detection element 12, that is, the output signal of the gas analyzer, is measured.After being filtered and dust removed, the infrared light is sent to the deformation cell 5, which is the so-called gas sampling method. is widely used. However, when such a gas sampling method is adopted, the sampling path becomes long and a pressure drop occurs in the filter, so it takes time to replace the sample gas in the measurement cell 5, and as a result, the response of the analyzer becomes slow. , processes that require close response speeds.Also, this sampling method has the problem of requiring time and effort to maintain the filter.

[Purpose of the invention]

The present invention solves the problems in conventional infrared gas analyzers as described above, and allows sample gas to be sent to the measurement cell without using a dust filter.As a result, high-speed response is possible and measurement accuracy is improved. It is an object of the present invention to provide an infrared gas analyzer which is capable of continuous measurement without being degraded by dust.

[Key Points of One Blade] In order to achieve the above-mentioned object, the present invention has a cylindrical main body and infrared a transmission windows provided at both ends of the main body, so that sample gas is guided inside. The measuring cell is equipped with a measuring cell, which transmits infrared rays through the infrared transmitting window, and detects the amount of the transmitted infrared rays to measure the concentration of the gas component to be measured contained in the sample gas. In such an infrared gas analyzer, a plate-shaped window mounting member, a closing plate drive mechanism, and a cleaning mechanism are provided, a sealing member such as a QIJ ring is attached to the end face of the main body, and, on the other hand,
The infrared transmitting window is attached to the member by airtightly penetrating the member so that both surfaces on the main body side form one plane, so that the two constitute a closing plate, and the closing plate is The closing plate is driven so that the closing plate is moved while sliding with respect to the sealing member with the body side surface in contact with the sealing member and the closing plate airtightly closing the main body. further, a closing plate moves a surface of a portion of the infrared transmitting window, which is moved by the closing plate drive mechanism, on the main body side, to a position away from the measurement cell; If the cleaning mechanism is configured to automatically clean the part of the infrared transmitting window to which dust in the sample gas adheres, it is possible to prevent the sample gas from leaking from the measurement cell (continuously or intermittently). The infrared gas analyzer By configuring a This improves maintainability and allows the gas analyzer to perform continuous measurements even on sample gases containing dust.

[Embodiments of the invention] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic vertical sectional side view of one embodiment of the infrared gas analyzer according to the present invention, and FIG. 4 is a plan view for explaining the main part of FIG. 3. In FIGS. 3 and 4, 15a and 15b are end faces of the main body 15 on the light source 1 and detection unit 9 sides, respectively, and are formed on one plane, and these end faces are provided with sealing members, respectively. as Q I
Infrared IO made of calcium fluoride with a J-shaped 181° shape,
The infrared transmitting windows 191'i6 and 192 are members 201 and 202 with window dams, respectively, and the infrared transmitting windows 191'i6 and 192 are coaxial with the members. These mounts are secured to the member by threading fluid. 211 and 212 are gear teeth provided on the outer surface of the members 201 and 202, respectively. 221, 222 are as described above, infrared transmission % 191, 192 and window installation is part system 201.2
02, and the closing plates 221 and 222 close the end faces 15a and 15b of the main body 15 by a portion of the infrared transmitting windows 191 and 192, respectively.
itl! They are arranged so as to close the valley openings of portions I, and on the end surfaces of these closing plates, the surfaces of the infrared transmitting windows and the surfaces of the window mounting portions I are formed on one plane. 231 and 232 are each window mounting member 201
, 202 are shafts fixed at the center of the closing plates 221, 222, 241° 242 are bearings of these shafts 231, 232, 251° 252 are gears meshing with the teeth 211, 212, respectively, and 26 are gears 251, 252. 27 is a motor that drives the shaft 26, and the blockage plate 22
1°222 is @26 by motor 27, gear 251
252, the shaft 231.2 sequentially through the teeth 211.212
They rotate simultaneously around 32. At this time, these closing plates 221 and 222 do not come into contact with the O-rings 181 and 182 and block both ends of the main body part 150 at the infrared transmitting windows 191 and 192, but slide the contact surfaces with the O-rings 181 and 182. It is configured to move and rotate.

28 are shafts 231, 232, bearings 241, 242, and teeth 211 that drive the closing plates 221, 222 as described above.
, 212, gears 251, 252, shaft 26 and motor 2
This is a closing plate drive mechanism consisting of 7. In the above-described embodiment, the closing plates 221 and 222 are driven by a gear mechanism, but even if they are driven by a roll mechanism, they will not be supported.

Blades 291 and 292 are located on the main body s15 side of the closing plates 221 and 222, respectively, and are provided radially on the side opposite to the main body 15 side with respect to the shafts 231 and 232. Width L1. L
are formed to have the same width as the circular ring of the infrared transmitting windows 191, 192, and the tips of the blades 291. 292 is configured as described above, and as the closed substrates 221 and 222 rotate, when the open end of the main body 15 is closed, the infrared rays attached to the dust contained in the sample gas in the main body are emitted. Transparent window 1
When the parts 91 and 192 are at the position of the blades 291 and 292, the adhering dust is automatically removed by these grades as the closed substrates 221 and 222 rotate. That is, the blades 291 and 292 are It has the function of a cleaning mechanism that cleans the infrared transmitting windows 191 and 192 as described above.

This cleaning mechanism may be an air jet mechanism instead of the blade as described above.

In the embodiment shown in FIG. 3, since the analyzer is constructed as described above, the infrared transmitting window 1 on which dust in the sample gas is attached
The portions 91 and 192 are continuously moved outside the measurement cell by the closing plate drive mechanism 28 without leaking the sample gas outside the measurement cell 5, and are automatically cleaned by blades 291 and 292 as cleaning mechanisms. be done. That is, in this analyzer, even if the closing plates 221 and 222 rotate, the open end of the main body 15 is always infrared transmitting windows 191 and 192.
The portions of these transparent windows that cover the main body portion 15 are always kept clean by the blades 291 and 292. In the above embodiment, the blade 291
．． 292 relative to the axes 231 and 232 of the main body 15.
Although the number of each blade is one, it is noted that these blades may be placed at any position outside of the measurement point 5, and that the number of blades may be plural. It is clear that there may be only one.

FIG. 5 is a plan view of another embodiment of the closure plate in FIG. 3. In the closure plate 301 in FIG. Four shaped infrared transmitting windows 31 are provided symmetrically with respect to the axis 231. In the analyzer of FIG. 3, the occluding plate 221.
When such a closing plate 301 is used instead of 222,
By configuring the closing plate drive mechanism to intermittently rotate these closing plates to bring the infrared transmitting window 31 to the position of the main body 15, the analyzer can be operated almost continuously while cleaning the infrared transmitting window with a blade. can be operated. In this case, the blades 291 and 292 are arranged at an angle of 90 degrees with respect to the shaft 231 so as to sandwich the transparent window located symmetrically to the transparent window 31 blocking the main body 15, as shown in FIG. When two of each are placed,
This is convenient for cleaning the transmission window 31.

The above embodiments were related to a single beam type infrared gas analyzer, but by applying the configuration 11/y shown in Figure 3 to the measurement cell part in Figure 1, a double beam type infrared gas analyzer can be constructed. It is clear that leaning is carried out in the same way as in the case of FIG. It is also clear that leaning can be performed in the same manner as described above.

〔Effect of the invention〕

As explained above, in the present invention, there is provided a measurement cell which is composed of a cylindrical main body and infrared transmitting windows provided at both ends of the main body, into which a sample gas is introduced, and an infrared ray is transmitted through the infrared transmitting windows. a light source section that transmits the infrared light through the measurement cell; and a detection section that detects the amount of the infrared light that has passed through the measurement cell, and the detection section measures the concentration of the measurement component gas in the sample gas. In an infrared gas analyzer, a plate-shaped window mounting member, a closing plate drive mechanism, and a cleaning mechanism are provided, and the plate-shaped window mounting member is formed so as to be on one plane at the end face of the main body, and a sheet/I/I/ The member is mounted, the infrared transmitting window is airtightly penetrated through the member, and the infrared transmitting window and the window mounting are arranged so that the surfaces of the members on the main body side are on one plane. The infrared transmitting window and the window mounting member constitute a closing plate, and a surface of the closing plate on the main body side is brought into contact with the sealing member to close the main body'? : The closing plate driving mechanism is configured to close and move the closing plate by sliding it with respect to the sealing member, and the body portion of the infrared transmitting window that is moved by the closing plate driving mechanism is closed. The infrared gas analyzer is configured such that the cleaning mechanism is configured to clean the surface of the exposed portion on the main body side at a position away from the measurement cell as the closing plate moves. In such a gas analyzer, the portion of the infrared transmitting window to which dust in the sample gas has adhered is operated by a closing plate drive mechanism to prevent sample debris from leaking from the measurement cell (continuously or intermittently).
: R+1 is moved to a position away from the constant cell, and during this movement, the dust adhering to the transmission window is automatically cleaned by a cleaning mechanism outside the measurement cell, and the cleaned part of the transmission window is It is installed again in the main body of the measuring cell by the closing plate drive mechanism. Therefore, in such a gas analyzer, the inner surface of the infrared transmitting window in the measurement cell is always kept in a clean state with little dust adhesion, so according to the present invention, there is no need to use a dust filter to clean the sample gas. As a result, it is possible to construct an infrared gas analyzer that has good responsiveness and maintainability, has little deterioration in measurement accuracy, and is capable of continuous measurement.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of conventional double-beam and single-beam infrared gas analyzers, respectively; FIG. 3 is a schematic longitudinal sectional side view of an embodiment of the infrared gas analyzer according to the present invention; and FIG.
The figure is a plan view for explaining the main part of Fig. 3, and Fig. 5 is a plan view for explaining the main part of Fig. 3.
FIG. 3 is a plan view of the embodiment. 1...Light source part, 5...Measurement cell, 9.
...detection section, 15 ... main body section, 15 a
, 15 b-old one end surface, 16.17... Infrared transmission window, 28... Closure plate drive mechanism, 18
1, 182... O-ring as a sealing member, 191, 192... Infrared transmitting window, 201
．． 202...Window mounting is a component, 221, 22
2... Closure plate, 291.292... Blade as cleaning mechanism, 301...
Occlusion plate. Figure 1 Figure 2 Figure 3 Figure 7

Claims (1)

[Claims] A measurement cell is comprised of a cylindrical main body and infrared transmission windows provided at both ends of the main body, into which a sample gas is introduced, and infrared rays are transmitted through the measurement cell through the infrared transmission windows. In an infrared gas analyzer that includes a light source section and a detection section that detects the amount of the infrared light transmitted through the measurement cell, the infrared gas analyzer measures the concentration of the measurement component gas in the sample gas by the detection section, For mounting, a member, a closing plate driving mechanism, and a cleaning mechanism are provided, and the sealing member is mounted on the end face of the main body portion, and the infrared transmitting window is mounted on the window mounting member. is airtightly penetrated through the member, and the infrared transmitting window and the window mounting are formed so that the surfaces of the members on the main body side are on the same plane, and the infrared transmitting window and the window mounting are and a closure plate, the main body side surface of the closure plate is brought into contact with the sealing member to close the main body, and the closure plate is slid relative to the sealing member at °C. The occluding plate driving mechanism is configured to close the main body side surface of the portion of the infrared transmitting window that is moved by the occluding plate driving mechanism, and which is moved by the occluding plate driving mechanism, at a position away from the measurement cell. An infrared gas analyzer characterized in that the cleaning mechanism is configured to clean the plate as it moves.