JP2003194674A - Infrared gas analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the detection accuracy by improving the constitution for switching a gas flowing in a cell between a calibration gas and a measuring gas in an infrared gas analyzer. <P>SOLUTION: A gas introduction part 2 is equipped with a body 21 wherein an internal space communicated with the inside of a sample main pipe 4 is formed, a gas introduction pipe 22 inserted inside the body 21, and a calibration gas introduction pipe 23 connected to the body 21. At the reference signal detection time, the calibration gas is supplied from the calibration gas introduction pipe 23 at the higher pressure than the sample gas pressure in the sample main pipe 4. On the other hand, at the measuring signal detection time, the pressure in the calibration gas introduction pipe 23 is reduced lower than the sample gas pressure, and supply of the calibration gas is stopped. A narrowed part 25 for narrowing a passage area is interposed in the gas introduction pipe 22. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared gas analyzer, and more specifically, to a sample gas to be inspected and a calibration gas for obtaining a reference signal, which are alternately flown in a cell. The present invention relates to an improvement in technology related to switching of these gases.

[0002]

2. Description of the Related Art In an infrared gas analyzer which is a measuring instrument for detecting the concentration of a specific gas component contained in a sample gas, a sample gas and a calibration gas are made to flow alternately in a cell. Conventionally, a method using a flow path switching valve such as a three-way solenoid valve has been adopted for the periodic switching of the circulating gas.

Japanese Patent Laid-Open No. 7-174699 discloses a cell by periodically driving a three-way solenoid valve interposed between a gas inlet of the cell and a sample gas introducing pipe and a calibration gas introducing pipe. A method of switching the gas flowing through the inside is disclosed. That is, the selection direction of the three-way solenoid valve is first set to the calibration gas introduction pipe side, the calibration gas is allowed to flow in the cell to obtain the reference signal, and then this selection direction is switched to the sample gas introduction pipe side to measure the measurement signal. To get.

Further, Japanese Patent Application Laid-Open No. 10-212253 does not describe switching of gas by a flow path switching valve, but discloses a method of evacuating a cell when detecting a reference signal. In order to create a vacuum inside the cell, in this publication, a sample gas introduction pipe connected to the inlet of the cell is provided with a flow control valve.

[0005]

However, as disclosed in these documents, a valve device such as a three-way solenoid valve is used to switch the gas flowing in the cell between when the reference signal is detected and when the measurement signal is detected. In the configuration, the calibration gas is
Since the gas is supplied through the flow path switching valve and the introduction tube provided separately from the sample gas introduction tube, the reliability of the reference signal is not sufficient. In other words, the detection result obtained by the relative evaluation with respect to the reference signal includes an error due to the different introduction paths of the calibration gas and the sample gas.

Further, in the structure in which the calibration gas is not required due to the reduced pressure, it takes a long time for the depressurization process by the vacuum pump until the pressure at which the calibration gas is not required is obtained, so that high speed measurement cannot be performed. The present invention has been made in view of such circumstances, and an object thereof is to make the gas introduction path a configuration that does not require a flow path switching valve, thereby making the introduction of sample gas efficient and improving the detection accuracy. In point.

Another object of the present invention is to improve the reliability of the reference signal by making the introduction conditions of the calibration gas and the sample gas uniform.

[0008]

Therefore, in the invention described in claim 1, in the infrared gas analyzer for detecting the concentration of the specific gas component in the sample gas to be inspected,
A cell and a gas introduction system for selectively introducing the sample gas or the calibration gas from the sample gas collection source to the cell are provided, and this gas introduction system is (A) sample gas collection source and sample gas inlet (B) One end is connected to the inlet side of the cell and the other end is connected to the main body of the gas introduction part, and the gas is collected from the tip part thereof. A gas introduction pipe whose mouth is located in the above-mentioned internal space (hereinafter referred to as "main body internal space")
And (C) a passage communicating with the internal space of the main body is formed, and the calibration gas supply means is configured to supply the calibration gas to the gas introduction portion main body through the passage at a predetermined pressure. A first operating state in which gas is supplied at a relatively high first pressure, and the supply of calibration gas is stopped, or the pressure of the calibration gas in the passage is set to a second pressure lower than the first pressure. It is decided to operate by switching between the second operating state and the second operating state.

According to the second aspect of the invention, a sample main pipe for circulating the sample gas is further provided as a sample gas sampling source, and the first pressure is set to a pressure higher than the sample gas pressure in the sample main pipe. In the invention according to claim 3, the second pressure is further set to a pressure lower than the sample gas pressure.

According to such a configuration, the calibration gas is the first
When supplied at a pressure of 1, the sample gas is prevented from flowing into the internal space of the main body, and this space is filled with the calibration gas. The filled calibration gas is introduced into the cell via the gas introduction pipe. On the other hand, when the supply of the calibration gas is stopped or the pressure of the calibration gas is lowered to the second pressure, the calibration gas filled in the internal space of the main body is pushed out by the sample gas, The filled gas is switched to the sample gas. Therefore, the gas introduced into the cell is also switched to the sample gas.

According to the fourth aspect of the invention, the opening direction of the gas sampling port is orthogonal to the inflow direction of the sample gas into the internal space of the main body. According to the invention of claim 5, in the gas introduction pipe,
A tube wall portion was provided that crossed between the gas sampling port and the sample gas inlet of the gas introducing unit body. According to the invention described in claim 6, the gas introducing pipe is provided with the throttle portion for temporarily narrowing the flow passage.

In the invention described in claim 7, the inner diameter of the gas introducing pipe is 1 mm, and the inner diameter of the throttle portion is 0.4 mm to
It was 0.5 mm. In the invention according to claim 8, the gas introducing portion main body is configured to include a hollow cylindrical member that surrounds the tip end portion of the gas introducing pipe, and the tip end portion of the gas introducing pipe is formed in the internal space of the tubular member. Was vertically cut and stretched to the vicinity of the facing wall surface.

According to the ninth aspect of the invention, in the gas introducing portion main body, the sample gas inlet portion is located upstream and the calibration gas inlet portion is located downstream of the flow direction in the gas introducing pipe. According to the tenth aspect of the invention, a passage is provided for communicating the internal space of the main body with the sample gas sampling source on the downstream side with respect to the flow direction of the sample gas inlet portion of the gas introducing portion main body.

According to the eleventh aspect of the present invention, the inner diameter of the communicating passage is 0.2 mm to 0.3 mm. In the invention described in claim 12, a means for forming a suction negative pressure is further provided in the gas introduction system, and the suction negative pressure is -26 kPa to.
It was set to -80 kPa.

[0015]

According to the inventions of claims 1, 2 and 3, it is possible to switch the gas flowing in the cell between the sample gas and the calibration gas without using the flow path switching valve. The sample gas can be smoothly introduced into the cell, and the time required for gas switching can be shortened.

Further, since the sample gas and the calibration gas are introduced into the cell under the same condition after the internal space of the main body, a highly reliable reference signal can be obtained. According to the invention of claim 4, since the opening direction of the gas sampling port is orthogonal to the flow of the sample gas, it is possible to reduce the influence of the dynamic pressure of this flow on the gas flowing into the gas introduction pipe.

According to the invention of claim 5, it is possible to prevent the sample gas from directly flowing into the gas introduction pipe after flowing into the internal space of the main body, so that the influence of the dynamic pressure can be further mitigated. According to the invention of claim 6, by providing the throttle portion in the gas introduction pipe, it is possible to suppress the pressure change in the downstream portion of the throttle portion due to the pressure change in the upstream portion of the throttle portion, and to stabilize the flow rate in the cell. .

According to the invention of claim 7, dimensions suitable for the throttle portion according to the present invention are provided. According to the invention of claim 8, the flow path in the main body is in the gas introduction pipe,
Due to the double formation with the outside, it is possible to prevent gas other than the gas to be introduced from flowing into the gas introduction pipe.

According to the invention of claim 9, when the calibration gas is introduced, the pressure of the calibration gas in the vicinity of the gas sampling port becomes substantially equal to that when the sample gas is introduced, so that the introduction conditions of each gas should be the same. You can According to the invention of claim 10, the calibration gas remaining in the internal space of the main body is scavenged through this passage when the gas is switched to the sample gas, so that the gas can be switched efficiently.

According to the eleventh aspect of the present invention, suitable dimensions are provided for the passage according to the present invention. Claim 1
According to the invention of 2, the suction negative pressure suitable for the infrared gas analyzer of the present invention is provided.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a non-dispersive infrared gas analyzer (hereinafter referred to as “ND”) according to an embodiment of the present invention.
Abbreviated as "IR". 3) is a configuration diagram of FIG. The NDIR 1 is roughly divided into a gas introduction section indicated by reference numeral 2 and a concentration detection section indicated by reference numeral 3.

First, in the gas introduction section 2, a sample gas to be tested (a specific gas component whose concentration is to be detected,
For example, CO, CO ₂ , H ₂ O, NO or NH ₃ is included. ) Is collected from the sample main tube 4 at a predetermined suction negative pressure. The sample main pipe 4 is for the gas flowing through a pipe (for example, a gas passage on the anode or cathode side of a fuel cell or an exhaust passage of an engine) provided in another device completed separately from the NDIR 1. It is selected for evaluation or provided as a part of NDIR1.

FIG. 2 shows an enlarged cross section of the gas introduction part 2. As shown in the figure, the gas introduction part 2 has a hollow cylindrical gas introduction part main body (hereinafter abbreviated as “main body”) 21 whose one end faces the inside of the sample main tube 4, and an inside of the main body 21 ( (Corresponding to the "internal space of the main body") to the concentration detecting unit 3, a calibration gas purifier for detecting a reference signal or a tank (not shown) for the calibration gas, and a main body 21. A calibration gas introducing pipe 23 to be connected and a ventilation thin tube 24 for communicating the inside of the main body 21 with the inside of the sample main pipe 4 are provided on the opposite side of the end of the main body 21 facing the inside of the sample main pipe 4. Composed.

The main body 21 is fixedly installed on the sample main tube 4, and the upper and lower (left and right in the figure) both ends of the gas introducing tube 2 are fixed.
It is closed except for a hole 211 for inserting 2.
Further, the side wall has a plurality of holes (hereinafter referred to as “sample gas introduction holes”) that communicate the inside and the outside (the inside of the sample main tube 4).
212 are formed at equal intervals on the circumference. The gas introducing pipe 22 is inserted into the main body 21 from the opposite side of the main body 21 from the side opposite to the main sample pipe 4 and extends to the vicinity of the end wall surface on the main sample pipe 4 side. The tip of the gas introduction tube 22 is inclined with respect to the central axis of the tube, and a gas sampling port 221 opening at the tip and a specific sample gas introduction hole 212 (“the sample gas (Corresponding to "the inlet portion"), the tube wall of the gas introduction tube 22 is interposed. Further, the gas introduction pipe 22 is provided with a throttle portion 25 that simplifies the flow passage area at a simple position outside the main body 21.

The calibration gas introducing pipe 23 is connected to the side wall of the main body 21, which is opposite to the side where the sample gas introducing hole 212 is formed. A check valve 26, which allows a flow toward the inside of the main body 21 and blocks a flow in the opposite direction, is provided upstream of the connection position with the main body 21. The ventilation thin tube 24 communicates with the inside of the main body 21 and the inside of the sample main tube 4 separately from the sample gas introduction hole 212 as described above, and regarding the flow of the sample gas in the sample main tube 4, the main body 21 (particularly, It is connected to the sample main pipe 4 on the downstream side of all the sample gas introduction holes 212).

In the present embodiment, the dimensions of each constituent part are such that the inner diameter φ1 of the gas introduction pipe 22 is 1 mm, the inner diameter φ2 of the throttle portion 25 is 0.4 to 0.5 mm, and the ventilation thin tube 24 is
Has an inner diameter φ3 of 0.2 to 0.3 mm. The calibration gas introduction pipe 23 and the ventilation thin pipe 24 are connected to the main body 21 at axially symmetrical positions. Here, the calibration gas introduction pipe 23 is provided on the upstream side with respect to the flow of the sample gas in the sample main tube 4.
However, ventilation thin tubes 24 are connected to the respective downstream sides thereof.

On the other hand, the concentration detector 3 can be constructed in the same manner as any known non-dispersive infrared gas analyzer. Here, the infrared light source 31, the chopper 32, the chopper motor 33, the cell 34, the optical filter 35, and the infrared sensor 36 are included. Here, the gas introduction pipe 22 extending from the gas introduction unit 2 is connected to the inlet 341 of the cell 34.

As components other than the above, in the discharge side pipe 51 extending from the outlet portion 342 of the cell 34, a vacuum pump 52 for forming a negative suction pressure of the sample gas and the calibration gas, and pressure pulsation in the cell 34. A buffer tank 53 for suppressing and a pressure adjustment control valve 54 for adjusting the suction negative pressure are installed. In the present embodiment, the suction negative pressure is −26 kPa (= −200 mmHg) to −80 kP.
It is set to a (= -600 mmHg).

Next, regarding the operation of NDIR1, cell 3
A description will be given separately for the case of detecting the reference signal by passing the calibration gas in 4 and the time of detecting the measurement signal by passing the sample gas in cell 34. In order to distribute the gas in the cell 34,
The pump 52 operates, and the suction negative pressure adjusted by the pressure adjustment control valve 54 acts on the gas sampling port 221 via the discharge side pipe 51, the cell 34, and the gas introduction pipe 22.

For the sake of convenience, the operation when detecting the measurement signal will be described below. When the measurement signal is detected, the calibration gas pressure in the calibration gas introduction pipe 23 is set lower than the sample gas pressure in the sample main pipe 4. As a result, the check valve 26 is closed and the supply of the calibration gas is stopped, and based on the suction negative pressure acting on the gas sampling port 221, the sample main tube 4 to the main body 21 is stopped.
A sample gas is introduced into the sample gas through the sample gas introduction hole 212.

Referring to FIG. 3, the sample gas introduced from the sample gas introduction holes 212 on the circumference upstream of the sample gas flow F in the sample main tube 4 flows through the tip of the gas introduction tube 22. It bypasses to reach the gas sampling port 221 (arrow f1). Therefore, the sample gas is introduced into the gas introduction pipe 22 without being affected by the dynamic pressure of the flow passing through the bypass path in the sample gas introduction hole 212.

The sample gas introduced into the gas introduction pipe 22 is
It is supplied to the cell 34 after passing through the throttle portion 25. When the sample gas passes through the constricted portion 25, the sample main pipe 4 undergoes a rapid pressure change (for example, atmospheric pressure + several meters).
Even if a change of approximately 2 times from mHg to 2 atm) occurs, the flow rate of the sample gas on the downstream side of the throttle portion 25 is kept substantially constant.

In the density detector 3, the chopper 32 is
It is rotated by the chopper motor 3. Infrared rays as continuous light emitted from the infrared light source 31 are radiated into the cell 34 as intermittent light through the chopper 4. The infrared ray as the intermittent light is absorbed by the sample gas flowing through the cell 34 according to its characteristics. The infrared light transmitted through the cell 34 is qualified by the optical filter 35 according to the specific gas component (for example, CO) whose concentration is to be detected, and the intensity thereof is detected by the infrared sensor 36.

Next, the operation when the reference signal is detected will be described. When the reference signal is detected, the calibration gas is supplied to the main body 21 at a predetermined pressure Pc via the calibration gas introduction pipe 23. By setting this pressure Pc to a value higher than the sample gas pressure Pt in the sample main tube 4, the sample main tube 4
The flow of sample gas from the
The gas with which the main body 21 is filled is switched to the calibration gas.

Referring to FIG. 4, the calibration gas that has passed through the check valve 26 and flowed into the main body 21 passes through an annular passage formed between the inner wall of the main body 21 and the outer wall of the gas introduction pipe 22. It reaches the gas sampling port 221 (arrows f2 and f3). The suction negative pressure acts on the calibration gas that has reached here, and the calibration gas is introduced into the gas introduction pipe 22. The introduced calibration gas is supplied to the cell 34 via the throttle portion 25.

Here, the calibration gas flows into the gas introduction tube 22, and also the sample gas introduction hole 212 and the ventilation thin tube 24.
To the sample main tube 4 (arrow f4), the effect of the calibration gas flowing into the sample main tube 4 in this way is negligibly small. The gas flow rate to be supplied to the cell 34 for concentration detection is 300 to 600 per minute.
This is because a small amount of about mL is enough.

The calibration gas flowing into the main body 21 is
After passing through the annular passage, it diffuses once before being introduced into the gas introduction pipe 22 (arrow f3). Along with this, the pressure corresponding to the internal and external differential pressure of the main body 21 is released from the sample gas introduction hole 212. Therefore, the gas sampling port 221
The pressure of the calibration gas in the vicinity of is almost equal to that when the measurement signal is detected, and the subsequent paths are also common to those when the measurement signal is detected. Therefore, the calibration gas is supplied to the cell 34 under the same condition as the sample gas introduction condition, in other words, under substantially the same condition as when the calibration gas is sucked and introduced from the sample main tube 4.

The concentration detecting section 3 detects the intensity of infrared rays transmitted through the cell 34 in the same manner as described above, and outputs a reference signal corresponding to the absorption characteristic of the calibration gas. Then, by the relative evaluation of the magnitudes of the output reference signal and the measurement signal, the concentration of the specific gas component contained in the sample gas is detected. Next, when detecting the measurement signal again, the supply of the calibration gas is stopped and the sample gas is introduced. At this time, the main body 2
The calibration gas left inside 1 (in particular, the annular passage between the main body 21 and the gas introduction pipe 22) is discharged (or scavenged) via the ventilation thin tube 24. Since the ventilation thin tube 24 is connected to the sample main tube 4 on the downstream side of the sample gas introduction hole 212 of the main body, the discharged calibration gas is discharged from the main body 2.
It will not be reintroduced to 1.

When the sample gas is switched to the calibration gas, a part of the calibration gas introduced into the main body 21 through the calibration gas introduction pipe 23 is introduced into the sample main pipe 4 through the ventilation thin tube 24. leak. However, since the inner diameter φ3 of the ventilation thin tube 24 is set to a very small value, the calibration gas that flows out in this way is very small, and the flow rate toward the gas sampling port 221 through the annular passage is sufficient. Reserved.

Next, the effect of interposing the narrowed portion 25 in the gas introduction pipe 22 will be described based on the concrete experimental results shown in FIG. Here, as the sample gas, N ₂ containing CO as a specific gas component at a concentration of 1000 ppm was used, and as the calibration gas, N ₂ was used. In FIG. 5, the horizontal axis represents the pressure in the sample main tube 4, and the vertical axis represents the detected CO concentration.

[0041] As shown in FIG. 5, the pressure in the sample main tube 4
At the concentration detected under the condition of 2 atm or less,
When the part 25 is not provided (B), the reference output value level
There is a 5% error with respect to (equivalent to 1000 ppm)
include. On the other hand, when the throttling part 25 is interposed,
In case (A), this error is suppressed to 1% or less,
The influence on the detection based on the pressure in the tube 4 is suppressed, and
You can see that the degree is improving.

FIG. 6 shows the detection accuracy when a flow path switching valve (here, a solenoid valve) is used for switching between the calibration gas and the sample gas, from the viewpoint of the setting accuracy of the reference signal. is there. As an experimental apparatus, as shown in FIG. 7, a cell 101, a sample gas introduction pipe 103, and a calibration gas introduction pipe 1
The analysis device in which the flow path switching valve 102 is interposed between the analyzers 04 and 04 was used. The calibration gas and the sample gas are shown in FIG.
The same as that selected in the experiment was used.

In FIG. 6, the vertical axis represents the concentration (sample gas line detection value) detected when the supply sources of the calibration gas and the sample gas are installed in a normal relationship, and the horizontal axis is shown. , These supply sources are installed in an inverse relationship to the normal ones, and the concentrations detected when the sample gas is introduced from the original calibration gas introduction pipe 104 and the calibration gas is introduced from the original sample gas introduction pipe 103 (calibration gas Line detection value).

The plot Pp which is the experimental result is 1000
Located outside the range of 1% based on the straight line L corresponding to ppm, the sample gas line detection value M1 is larger than the value Mr (= 1000 ppm) corresponding to the plot Pi on the straight line L, and the calibration gas line detection value M2 is smaller than the value Mr (thus M1> M2). This difference in the result despite the fact that the same gas was supplied to the cell 101 was caused by the relative magnitude of the reference signal with respect to the measurement signal when the detected value M1 was detected and when the detected value M2 was detected. This is because it differs from when it was detected. The difference is due to the different introduction paths of the calibration gas and the sample gas inside the flow path switching valve 102 and the like.

On the other hand, in the NDIR 1 according to the present invention, the introduction paths of these gases may be regarded as being the same. Therefore, the detected reference signal is accurate and reliable, and the detected concentration matches the plot Pi on the straight line L. As described above, according to the present invention, it is not necessary to interpose an element that obstructs the flow such as a flow path switching valve in order to switch the gas to be circulated in the cell 34 between the calibration gas and the sample gas. According to the NDIR 1 according to the above-described embodiment, the time required to introduce the sample gas from the sample main tube 4 into the cell 34 is extremely short (the time required to switch to the sample gas is 0.1 seconds or less. ), The change in the concentration of the characteristic gas component in the sample main tube 4 can be detected in real time.

Further, the calibration gas and the sample gas are introduced in common (after the gas sampling port 221) and the introduction conditions of these gases are made equal, so that the reliability of the reference signal is enhanced. . Furthermore, since the pressure change at the downstream side is suppressed by interposing the throttle portion 25, the sample gas (and the calibration gas) can be supplied to the cell 34 at a stable flow rate, and high detection can be performed without pressure correction. Accuracy can be obtained.

Further, since the ventilation thin tube 24 is provided, the calibration gas remaining in the main body 21 is efficiently discharged when switching to the sample gas.
And done quickly. The infrared gas analyzer according to the present invention can obtain a highly accurate detection result in real time even in combination with a method of detecting the concentrations of a plurality of specific gas components simultaneously in a single cell.

[Brief description of drawings]

FIG. 1 is an overall configuration of a non-dispersive infrared gas analyzer according to an embodiment of the present invention.

[Fig. 2] Same as above, but with an enlarged cross section of the gas inlet of the analyzer.

[Fig. 3] Operation when a measurement signal is detected

[Fig. 4] Operation when a reference signal is detected

[FIG. 5] Effects of forming a narrowed portion

FIG. 6 is a comparison of detection accuracy between an infrared gas analyzer according to the present invention and a conventional device.

FIG. 7 shows an example of a conventional device

[Explanation of symbols]

1 ... Non-dispersive infrared gas analyzer (NDIR) 21 ... Main body 22 ... Gas introduction pipe 23 ... Calibration gas introduction tube 24 ... Ventilation thin tube 25 ... diaphragm part 26 ... Check valve 31 ... Infrared light source 34 ... cell 36 ... Infrared sensor 52 ... Pump 4 ... Sample main

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G052 AA39 AC23 AD42 BA14 CA04                       CA11 CA12 CA38 GA11 HC25                 2G059 AA01 BB01 CC04 CC05 CC09                       DD12 EE01 GG10 HH01 KK01                       MM14

Claims (12)

[Claims] 1. An infrared gas analyzer for detecting the concentration of a specific gas component in a sample gas to be tested, comprising a cell and a sample gas or a calibration gas from a sample gas sampling source selectively supplied to the cell. A gas introduction system for introducing the gas introduction system, wherein the gas introduction system is a gas introduction unit main body in which an internal space is formed which is constantly communicated with a sample gas sampling source through a sample gas inlet, and at one end of the cell A gas introducing pipe, which is connected to the inlet side and is connected to the gas introducing unit main body at the other end, and a gas sampling port at its tip is located in the internal space, and a passage communicating with the internal space of the gas introducing unit main body. And a calibration gas supply means for supplying a calibration gas to the gas introduction part main body through the passage at a predetermined pressure, and the calibration gas supply means is configured to relatively supply the calibration gas. High first
And a second operating state in which the supply of the calibration gas is stopped or the pressure of the calibration gas in the passage is set to a second pressure lower than the first pressure. Infrared gas analyzer characterized by switching with. 2. The infrared gas according to claim 1, further comprising a sample main tube for circulating the sample gas as a sample gas sampling source, wherein the first pressure is higher than the sample gas pressure in the sample main tube. Analysis equipment. 3. The infrared gas analyzer according to claim 2, wherein the second pressure is lower than the sample gas pressure. 4. The infrared gas analyzer according to claim 1, wherein the opening direction of the gas sampling port is orthogonal to the inflow direction of the sample gas into the internal space. 5. The infrared gas analyzer according to claim 4, wherein the gas introducing pipe has a pipe wall portion that crosses between the gas sampling port and the sample gas inlet of the gas introducing unit main body. 6. The infrared gas analyzer according to claim 1, further comprising a throttle portion that temporarily narrows a flow path in the gas introduction pipe. 7. The infrared gas analyzer according to claim 6, wherein the gas introducing pipe has an inner diameter of 1 mm, and the narrowed portion has an inner diameter of 0.4 mm to 0.5 mm. 8. The gas introducing portion main body is configured to include a hollow tubular member surrounding the tip portion of the gas introducing pipe, and the tip portion of the gas introducing pipe defines an internal space of the tubular member. The infrared gas analyzer according to any one of claims 1 to 7, which is longitudinally cut and extends to the vicinity of the facing wall surface. 9. In the main body of the gas introducing part, a sample gas inlet part is provided on the upstream side with respect to the flow direction in the gas introducing pipe,
The infrared gas analyzer according to claim 8, wherein a calibration gas inlet is located downstream of the calibration gas inlet. 10. The infrared gas analyzer according to claim 9, further comprising a passage for communicating an internal space of the gas introducing unit main body with a sample gas sampling source downstream of the sample gas inlet with respect to the flow direction. 11. The infrared gas analyzer according to claim 10, wherein the inner diameter of the passage communicating with the sample gas sampling source is 0.2 mm to 0.3 mm. 12. The gas introducing system further comprises means for forming a negative suction pressure, wherein the negative suction pressure is -26 kPa to -80.
The infrared gas analyzer according to claim 1, wherein the infrared gas analyzer is set to kPa.