JP2008151590A - Gas analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the actual weight of a very small amount of a gas in the gas to be measured by calculating the weight difference of the gas to be measured before and after heating by heating the gas to be measured. <P>SOLUTION: This gas analyzer for quantifying the very small amount of the gas contained in the atmosphere or the like is equipped with an electric oven (heating means) 31 for heating the gas to be measured and a measuring means for measuring the amounts of the gas before and after the gas to be measured is heated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas analyzer capable of quantifying a minute amount of gas contained in the atmosphere with high sensitivity, and more particularly to a specific gas in the atmosphere, a harmful gas in an automobile exhaust gas, a specific gas in an exhaled breath, and a structural material. The present invention relates to a gas analyzer capable of measuring a trace gas such as a specific gas contained with high sensitivity on the order of up to ppm.

Conventionally, when measuring a very small amount of gas in the atmosphere by mass spectrometry, the atmosphere (measuring gas) containing the gas to be measured (target gas) is continuously flowed into the ion source of the mass spectrometer. Although there is a difference of 100 million times (10 ⁸ ) or more between the pressure of the gas to be measured at or near atmospheric pressure and the pressure at which the mass spectrometer operates normally, several stages of differential exhaust are performed. The diameter of the gas inlet to the ion source of the mass spectrometer is extremely small.

  That is, the conventional gas analyzer is configured as shown in FIG. The gas analyzer includes a gas supply mechanism 1. Here, the gas supply mechanism 1 includes a measured gas reservoir 2, a pipe 4 provided with a variable leak valve 3, a manifold 6 provided with a pressure gauge 5, and a vacuum exhaust connected via the manifold 6 and the pipe 7. The apparatus 8 is comprised. The vacuum exhaust device 8 includes a turbo molecular pump 9 and a diaphragm pump 10. In addition, the gas analyzer includes a branch pipe 12 provided with an orifice plate 11 on the downstream side of the gas supply mechanism 1. The reference numeral 11a in the figure is the orifice of the orifice plate 11. The gas analyzer further includes a quadrupole mass spectrometer 14 having an ion source 13 on the downstream side of the branch pipe 12 and a vacuum exhaust device 15 connected to the mass spectrometer 14. The vacuum exhaust device 15 includes a turbo molecular pump 16 and a diaphragm pump 17.

  The operation of such an analyzer is as follows. That is, first, the two vacuum exhaust devices 8 and 15 exhaust the pipe 4 and the quadrupole mass spectrometer 14 on the downstream side of the variable leak valve 3 to a high vacuum, and the mass spectrometer 14 is put into an operating state. Next, the variable leak valve 3 is appropriately opened so that the indication of the pressure gauge 5 attached to the manifold 6 becomes a predetermined value. This predetermined value is a gas set in advance so that the pressure of the ion source 13 part of the mass spectrometer at this time becomes an optimum value for measurement by this value, the conductance of the orifice 11a, and the effective exhaust speed of the exhaust device. It is unique to the analyzer.

  In this state, a part of the measurement gas released from the measurement gas reservoir 2 flows into the ion source 13 of the quadrupole mass spectrometer 14 from the orifice 11 a of the orifice plate 11 provided near the manifold 6. By analyzing the mass spectrum of the gas, the concentration of the target gas in the gas to be measured can be measured.

  However, in the conventional gas analyzer shown in FIG. 7, if the variable leak valve 3 is throttled to reduce the amount of gas released from the gas reservoir 2 to be measured, it is difficult to finely adjust the flow rate, resulting in poor reproducibility. On the other hand, if the variable leak bulk 3 is opened to increase the amount of gas released from the gas reservoir 2 to be measured, the pressure in the manifold portion increases, so the orifice diameter needs to be extremely small. Therefore, there is a problem that the reproducibility is similarly deteriorated because the conductance of the orifice is changed or the orifice is clogged.

  In addition, since the conventional gas analyzer basically employs a method of continuously flowing the gas to be measured and measuring in a steady state, even if flow reproducibility is ensured, There is a problem that the detection sensitivity of the target gas is significantly lowered due to the influence of an adsorbent gas such as water vapor contained in a large amount in the gas to be measured.

That is, for example, when a trace amount of hydrogen present in the gas to be measured is to be measured, the analysis is performed while paying attention to the ratio of the mass number of ions to the charge m / e = 2 (H ₂ ⁺ ). When a large amount of water vapor is present in the gas, m / e = 1 (H ⁺ ) is generated. When the value of m / e = 1 is increased, the limit value of m / e = 2 adjacent thereto is also affected. For this reason, an accurate value of m / e = 2 due to hydrogen of the target gas cannot be read, resulting in a decrease in detection sensitivity.
An adsorptive gas such as water vapor is easily adsorbed on a tube wall or an electrode of a mass spectrometer, and once adsorbed, it does not easily desorb unless heated to a high temperature.

  Therefore, in order to use a gas analyzer based on mass spectrometry for the analysis of trace gases contained in the atmosphere, etc., the detection sensitivity is increased to the highest ppm order, and the accuracy (reproducibility) of measured values is improved. There are many issues to be improved, such as speeding up.

For these reasons, the present inventors have previously proposed a high-sensitivity gas analyzer in order to solve the above-described problems (Non-Patent Document 1). In this proposal, a gas to be measured is pulsed by adopting a configuration in which a small container with an on-off valve and a relatively large buffer tank connected to the small container through the on-off valve are provided in the gas to be measured introduction section. In addition, by introducing a part of the gas to be measured from the orifice into the ion source of the quadrupole mass spectrometer, trace gases such as a specific gas can be reproducible with high sensitivity on the order of ppm. It can be measured.
Japanese Patent Application No. 2004-234010

  By the way, according to Non-Patent Document 1, although a plurality of trace gases contained in the atmosphere or the like can be detected with high sensitivity, each gas is measured with a relative value and not with an absolute value. . Further, it has not been possible to measure how much trace gas is specifically contained in the gas to be measured.

  The present invention has been made in view of such circumstances, and includes heating means for heating the measurement gas and measurement means for measuring the gas amount before and after heating the measurement gas, thereby heating the measurement gas. Thus, an object of the present invention is to provide a gas analyzer capable of measuring the actual weight of a trace gas in a gas to be measured by obtaining a weight difference between the gas to be measured before and after heating.

  The present invention also provides a gas supply mechanism for flowing the gas to be measured in a pulse manner, a buffer tank disposed on the downstream side of the gas supply mechanism, and an ion source disposed on the downstream side of the buffer tank. By further comprising a quadrupole mass spectrometer provided, and an orifice plate for allowing a part of the gas to be measured from the gas supply mechanism to flow into the ion source of the quadrupole mass spectrometer, An object of the present invention is to provide a gas analyzer capable of measuring the absolute amount of each trace gas in a gas to be measured.

  A gas analyzer according to the present invention is a gas analyzer for quantifying a trace gas contained in the atmosphere, etc., a heating means for heating a gas to be measured, and a measuring means for measuring a gas amount before and after heating of the gas to be measured. It is characterized by comprising.

  According to the present invention, the actual weight of the trace gas in the measured gas can be measured by heating the measured gas and determining the weight difference between the measured gas before and after heating. Further, according to the present invention, a gas supply mechanism for causing the gas to be measured to flow in a pulse manner, a buffer tank disposed on the downstream side of the gas supply mechanism, and an ion disposed on the downstream side of the buffer tank, A quadrupole mass spectrometer having a source, and an orifice plate for allowing a part of the gas to be measured to flow from the gas supply mechanism into the ion source of the quadrupole mass spectrometer. Thus, the absolute amount of each trace gas in the gas to be measured can be measured.

Hereinafter, the present invention will be described in more detail.
As described above, the gas analyzer of the present invention includes the heating unit that heats the measurement gas and the measurement unit that measures the gas amount before and after heating the measurement gas.

  In the present invention, as the measuring means, 1) a method in which the sample in the sampling tube is taken out from the vacuum vessel before and after the measurement and measured in the atmosphere, or 2) a suspended balance is installed in the vacuum vessel using a vacuum manipulator. Thus, there is a method of continuously measuring a small amount of released gas from the sample in the sampling. Here, the measurement method according to 1) is effective when the weight change amount of the sample is large and the influence of the atmosphere can be ignored, and has a merit that a small amount of emitted gas can be measured at a low cost using a simple measurement device. The measurement method according to 2) has an advantage that it is possible to accurately measure a trace amount of emitted gas without being affected by impurities in the atmosphere, compared to measurement in the atmosphere. Specific examples of 2) are as shown in FIGS. 2 and 3 to be described later.

  In the present invention, a gas supply mechanism for flowing a gas to be measured in a pulse manner, a buffer tank disposed on the downstream side of the gas supply mechanism, and an ion source disposed on the downstream side of the buffer tank are provided. It is preferable to further include a quadrupole mass spectrometer and an orifice plate for allowing a part of the gas to be measured from the gas supply mechanism to flow into the ion source of the quadrupole mass spectrometer. With this configuration, the absolute amount of each component of the trace gas in the gas to be measured can be measured.

  The gas supply mechanism preferably includes a primary storage container connected to the buffer tank for temporarily storing a part of the gas to be measured and a plurality of on-off valves for opening and closing the primary storage container. . With such a configuration, the absolute amount of each component of the impurity gas adhering to the surface of the sampling tube can be measured. Here, the ratio of the internal volume of the temporary storage container to the buffer tank is preferably 1/10000 to 1/400. The reason for this numerical limitation is that when the above ratio is less than 1/400, the measuring means for measuring the gas amount (for example, a quadrupole mass spectrometer) is turned off and the gas amount cannot be detected. This is because if the ratio exceeds 1/10000, the sensitivity of the analyzer decreases. Here, the flow of the gas to be measured in the gas supply mechanism can be repeatedly reproduced by allowing the gas to be measured of a certain amount collected in the temporary storage container to flow out by fully opening the on-off valve at a high speed.

  In the present invention, it is preferable that cooling means for cooling a pipe through which the gas to be measured flows is disposed between the gas supply mechanism and the heating means. By providing the cooling means, it is possible to avoid a thermal adverse effect from the heating means to the buffer tank or the like.

  In the present invention, as the heating means, an electric furnace, or an electric furnace and at least one of high-frequency heating, laser heating, and a halogen lamp can be combined. Since an electric furnace is generally unsuitable for rapid heating, it is preferable to heat the impurity gas on the surface of the sampling tube by high-frequency heating suitable for rapid heating, laser heating or heat treatment using a halogen lamp. Rapid heating means such as high-frequency heating can be arranged inside or outside the heating tube that houses the sampling tube.

  In the present invention, it is preferable that an evacuation apparatus is connected to the quadrupole mass spectrometer. However, when the mass spectrometer is unnecessary, the cost can be reduced by using only one of the vacuum exhaust device or the vacuum exhaust device of the gas supply mechanism.

Next, specific examples of the gas analyzer according to the present invention will be described with reference to the drawings.
Example 1
A gas analyzer according to Embodiment 1 of the present invention will be described with reference to FIG.
Reference numeral 21 in the figure denotes a buffer tank having flanges 21a and 21b formed at both ends. A gas supply mechanism 23 is connected to one side (right side) of the buffer tank 21 so that the gas to be measured flows in a pulsed manner toward the buffer tank. The gas supply mechanism 23 includes a temporary storage container 24 having a flange 24 a formed on one side thereof, and open / close valves 25 and 26 provided in the temporary storage container 24. On one side of the temporary storage container 24, a cooling pipe (cooling means) 28 having a double wall structure for cooling the pipe 27 in which the flange 27a is formed is disposed. Cooling water is supplied to the cooling pipe 28 as shown by an arrow Y. A heating tube 29 having a flange 29 a is attached to one end side of the piping 27, and a sampling tube 30 that accommodates the gas to be measured is disposed in the heating tube 29.

  The gas analyzer further includes an electric furnace (heating means) 31 provided with a heater 31a for heating the heating tube 29 and the sampling tube 30, and the electric furnace 31 can move in the X direction. The heating pipe 29 can be detached from the pipe 27 at the flange 29a portion. A flange 32a is formed on one end side of the flange 21a on the other end side (left side) of the buffer tank 21, and a manifold 32 provided with a valve 33 on the way is connected. The manifold 32 includes an orifice plate 36 at the other end for allowing a part of the gas to be measured to flow into the ion source 35 of the quadrupole mass spectrometer 34 from the heating tube 29 side. The orifice plate 36 is a thin metal plate having a circular orifice (hole) 36a, and the diameter of the hole is about 0.3 mm. When the orifice plate 36 is thick, the hole diameter is larger than this.

  A first vacuum exhaust device 38 is connected to the buffer tank 21 via a pipe 37 having a valve 37a. The vacuum exhaust device 38 includes a turbo molecular pump 39 and a diaphragm pump 40. The quadrupole mass spectrometer 34 is disposed on the downstream side of the manifold 32, and a vacuum vessel 41 is disposed between the manifold 32 and the quadrupole mass spectrometer 34. A second vacuum exhaust device 43 is connected to the vacuum vessel 41 through a pipe 42. The vacuum exhaust device 43 includes a turbo molecular pump 44 and a diaphragm pump 45.

Next, an example in which impurity gas in, for example, 100 g of A356 (Al alloy) is measured using the gas analyzer having such a configuration will be described.
1) First, before introducing the gas to be measured containing impurities into the gas analyzer, the weight W ₁ of the gas to be measured is measured with a separately prepared balance. Here, the weight of the gas to be measured indicates the weight of the sampling tube 30, the gas, and the sample. Next, the flange portion 29a of the heating tube 29 containing the sampling tube 30 is aligned with the flange portion 27a of the pipe 27 and fixed with a bolt. Subsequently, the opening / closing valve 25 and the opening / closing valve 26 of the temporary storage container 24 are opened, and the first evacuation device 38 evacuates the heating tube 29 while the valve 37a of the pipe 37 is opened.

2) Next, when the inside of the heating pipe 29 reaches a predetermined pressure, evacuation is stopped, the on-off valve 26 is opened, and the on-off valve 25 is closed. Subsequently, the heating tube 29 and the sampling tube 30 are heated by the heater 31 a of the electric furnace 31, and the gas to be measured in the sampling tube 30 is packed in the temporary storage container 24. When the on-off valve 26 is closed, the gas to be measured having a constant volume of atmospheric pressure (approximately 1 atm, 10 ⁵ Pa) can be collected in the temporary storage container 24.

  3) Next, after opening the valve 37a and confirming that the first evacuation device 38 is operating with the valve 33 closed, the on-off valve 25 is fully opened at high speed. As a result, the gas to be measured in the temporary storage container 24 quickly diffuses into the buffer tank 21. At this time, the pressure in the buffer tank 21 once reaches a maximum value as shown in FIG. 4 and thereafter is exhausted by the first vacuum exhaust device 38, so that it gradually decreases. Note that the pressure in the manifold 32 changes in substantially the same manner as the pressure in the buffer tank 21.

  4) Here, the internal volume of the temporary storage container 24 is usually 0.1 to 0.5 mL, the internal volume of the buffer tank 21 is 0.2 to 1 L, and the ratio of both is about 1/2000. Therefore, the pressure in the buffer tank 21 and the manifold 32 immediately after opening the on-off valve 25 is approximately 50 Pa of 1/2000 atm. The effective exhaust speed in the buffer tank 21 and the manifold 32 by the first vacuum exhaust device 38 is 0.02 to 0.1 L / s, and the time constant of pressure decay (see FIG. 4) is around 10 seconds.

5) Next, the gas to be measured in the sampling pipe 30 is heated by the heater 31a of the heating furnace 31 while cooling the pipe 27 and the like by the cooling pipe 28. As a result, the temperature of the gas to be measured rises, and each component in the gas to be measured, for example, H ₂ , CO, H ₂ O, CO ₂ , C, C ₄ H ₇ comes out.

  6) Next, by operating the second vacuum exhaust device 43 with the valve 37a closed and the valve 33 opened, a part of the gas to be measured is passed through the vacuum vessel 41 from the buffer tank 21 and the manifold 32. Pour into the ion source 35 of the quadrupole mass spectrometer 34. Here, the effective exhaust speed of the second vacuum exhaust apparatus 43 is 20 to 100 L / s.

7) When the second evacuation device 43 is in an operating state and no gas flows from the orifice 36a, the pressure in the ion source 35 of the quadrupole mass spectrometer 34 is set to an ultrahigh vacuum of 10 ⁻⁵ Pa or less. It has become. However, when the gas to be measured exists in the manifold 32, a part of the gas to be measured flows into the ion source 35 through the orifice 36a and the vacuum vessel 41, and the pressure in the ion source 35 increases. The gas flowing into the ion source 35 is exhausted by the second vacuum exhaust device 43.

  8) Although the flow rate of the gas passing through the orifice 36a is substantially proportional to the pressure of the gas in the manifold 32, the effective exhaust speed of the second vacuum exhaust device 43 is substantially constant regardless of the pressure. The pressure of the measurement gas changes approximately in proportion to the pressure of the gas to be measured in the manifold 32, and the proportionality constant is represented by (orificance conductance) / (effective pumping speed of the second vacuum pumping device). In the first embodiment, the proportionality constant is approximately 1/10000 to 1/2000.

9) Quantification of the target gas (H ₂ , CO, H ₂ O, CO ₂ , C, C ₄ H _7, etc.) in the gas to be measured inside or on the surface of the sampling tube 30 is performed by the ion of the quadrupole mass spectrometer 34. The gas to be measured is ionized by the source 35, m / e ions peculiar to the target gas are separated by the quadrupole mass spectrometer 34, and the ion current is measured. Usually, the ion current when the ion current reaches the maximum is measured, and the absolute value is obtained from a calibration curve prepared in advance. In a specific embodiment of the present invention, trace gases up to the highest ppm order can be measured.

10) FIG. 6 shows the relationship between time and concentration (ion current) for each target gas. In FIG. 6, curves (a), (b), (c), (d), (e), and (f) are H ₂ , CO, H ₂ O, CO ₂ , C, and C ₄ H, respectively. ₇ curves are shown. From the characteristic diagram, the relative ratio of each target gas is calculated as follows.
H ₂ : S1 × 2 = S1 ′
CO: S2 × 28 = S2 ′
H ₂ O: S3 × 18 = S3 ′
CO ₂ : S4 × 44 = S4 ′
C: S5 × 12 = S5 ′
C ₄ H ₇ : S6 × 55 = S6 ′
However, S1, S2, S3, S4, S5, and S6 are the areas under the curves (a), (b), (c), (d), (e), and (f) in FIG. Integration value).
The relative ratio of each target gas is determined by S1 ′, S2 ′, S3 ′, S4 ′, S5 ′, and S6 ′. For example, the relative ratio of H ₂ is S1 ′ / (S1 + S2 ′ + S3 ′ + S4 ′ + S5 ′ + S6 ′). In this way, the relative ratio of other target gases can also be obtained.

11) Next, the weight W ₂ of the gas to be measured after heating is obtained with a separately prepared balance, and the weight difference ΔW = (W ₁ −W ₂ ) of the gas to be measured before and after heating is obtained. Therefore, the weight of each target gas in the gas to be measured can be obtained. For example, H ₂ can be obtained by the following equation.

H ₂ : ΔW × S1 ′ / (S1 + S2 ′ + S3 ′ + S4 ′ + S5 ′ + S6 ′)
In this way, the weight of another target gas can be obtained.

  According to the first embodiment, first, the gas to be measured can be introduced into the gas analyzer in a pulse manner using the temporary storage container 24 provided with the on-off valves 26 and 25 on the upstream and downstream sides of the gas to be measured, respectively. . As a result, the reproducibility of the gas flow is ensured, and the degree to which the tube wall and electrodes of the quadrupole mass spectrometer 34 are in contact with the gas to be measured is several orders of magnitude lower than that of a conventional gas flow apparatus. Therefore, as a result, the background pressure rise due to the adsorptive gas such as water vapor is suppressed, and the reduction of the detection sensitivity for the target gas can be prevented. Second, the weight of the gas to be measured before and after heating is measured using the heating furnace 31, and the weight of each target gas in the gas to be measured can be specifically measured based on the time-concentration characteristic diagram of FIG. . Therefore, according to the gas analyzer of Example 1, the actual weight of each target gas in the gas to be measured can be measured with high sensitivity.

  In addition, since the impurity gas adheres not only to the inside but also to the surface of the sampling tube 29, when the change of the time and the weight of the impurity gas of the sample is graphed, a sudden change in the weight is shown at the rising edge. It has become clear. This characteristic is believed to be due to the impurity gas on the surface of the sample.

(Example 2)
A gas analyzer according to Example 2 of the present invention will be described with reference to FIG. Since this gas analyzer differs from the gas analyzer of Example 1 only in the heating means and the measuring means, only the main part will be described. That is, in Example 1, the weight of the gas to be measured was measured using a separately prepared balance, but in Example 2, the measurement was performed using the measuring unit 51 and the heating unit having the configuration shown in FIG. Note that the same members as those in FIG.

  As shown in FIG. 2, the measuring means 51 includes a vacuum vessel 53 in which a window 52 for entering and exiting the heating tube 29 and the sampling tube 30 is formed. On the side wall of the vacuum vessel 53, a flange portion 53a is formed for positioning and fixing with the flange portion 27a of the pipe 27 of FIG. An electronic balance 54 is disposed above the vacuum container 53, and a tray 56 is suspended from the electronic balance 54 by a suspension member 55. A heater 57 for heating the heating tube and the sampling tube placed on the saucer 56 is placed around the saucer 56 in the vacuum container 53. A plate-like heat shielding plate 58 for shielding heat from the heater 57 is disposed between the electronic balance 54 and the tray 56. The material of the heat shielding plate 58 is stainless steel, for example. The heat shielding plate is not limited to a plate shape, and may be hollow so that water can flow inside.

  According to the gas analyzer having such a configuration, the vacuum vessel 53 provided with the flange portion 53a aligned with the flange portion 27a of the pipe 27, the tray 56 for housing the heating tube and the sampling tube, the electronic balance 54, the heater 57, and the like. Since the measurement means 51 includes the heat shielding plate 58, compared with the apparatus of the first embodiment, there is an effect that it is possible to accurately measure a trace amount of emitted gas without being affected by impurities in the atmosphere. can get.

Example 3
A gas analyzer according to Embodiment 3 of the present invention will be described with reference to FIG. Since this gas analyzer is only slightly different in configuration from the measuring means 51 of the gas analyzing apparatus of the second embodiment, only the main part will be described.
A reference numeral 59 in FIG. 3 indicates an elevating mechanism that moves the tray 56 up and down to the electronic balance 54. The raising / lowering mechanism 59 operates a manipulator (not shown) from the atmosphere side. After placing the heating tube and the sampling tube on the tray 56 from the window 52, the tray 56 is lowered to the electronic balance 54 side as indicated by an arrow A. And measure the trace emission gas.
According to the third embodiment, the same effect as the second embodiment can be obtained.

Example 4
Please refer to FIG. However, the same members as those in FIG. The gas analyzer according to the fourth embodiment is effective in measuring the change in the total amount of the impurity gas before and after heating, rather than measuring the weight of each target gas in the impurity gas, unlike the apparatus in the first embodiment. . Therefore, unlike the case of the first embodiment, the gas analyzer of the fourth embodiment does not require a quadrupole mass spectrometer, a second evacuation device, and an orifice plate.

  Thus, according to the gas analyzer of Example 4, the gas supply mechanism 23 for flowing the measurement gas in a pulse manner, the electric furnace 31 as a heating means for heating the measurement gas, and the measurement gas A balance (not shown) as a measuring means for measuring the amount of gas before and after heating is provided, and the gas supply mechanism 23 is provided in a temporary storage container 24 having a flange 24a on one side, and the temporary storage container 24. The open / close valves 25 and 26 are provided. Therefore, it is possible to measure a change in the total amount of impurity gas before and after heating. Further, compared to the case of the first embodiment, an expensive second evacuation device or the like can be dispensed with, so that the cost can be reduced.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Specifically, a quadrupole mass spectrometer is not always necessary. In this case, one of the first and second evacuation devices is unnecessary, and the orifice plate is also unnecessary. Moreover, you may combine the component covering different embodiment suitably.

FIG. 1 is an explanatory diagram of a gas analyzer according to a first embodiment of the present invention. FIG. 2 is an explanatory view of a measuring unit and a heating unit which are one configuration of the gas analyzer according to the second embodiment of the present invention. FIG. 3 is an explanatory view of a measuring unit and a heating unit which are one configuration of the gas analyzer according to the third embodiment of the present invention. FIG. 4 is a diagram schematically showing temporal changes in pressure in the buffer tank and manifold of the gas analyzer of FIG. FIG. 5 is a schematic diagram of a gas analyzer according to Embodiment 4 of the present invention. FIG. 6 is a characteristic diagram showing the relationship between time and concentration by the gas analyzer of FIG. FIG. 7 is an explanatory diagram of a conventional gas analyzer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Buffer tank, 23 ... Gas supply mechanism, 24 ... Temporary storage container, 25, 26 ... On-off valve, 27, 37, 42 ... Pipe, 28 ... Cooling pipe, 29 ... Heating pipe, 30 ... Sampling pipe, 31 ... Electricity Furnace, 32 ... manifold, 34 ... quadrupole mass spectrometer, 35 ... ion source, 36 ... orifice plate, 36a ... orifice, 38, 42 ... vacuum exhaust device.

Claims (9)

A gas analyzer for quantifying a minute amount of gas contained in the atmosphere or the like, comprising a heating means for heating a gas to be measured, and a measuring means for measuring a gas amount before and after heating of the gas to be measured. Analysis equipment. The measuring means includes a vacuum vessel, an electronic balance arranged in the vacuum vessel, a saucer placed in the vacuum vessel, on which a sampling tube for containing a gas to be measured is placed, and placed on the saucer. The gas analyzer according to claim 1, further comprising a heater unit that heats the sampling tube. The measuring means includes a vacuum vessel, an electronic balance arranged in the vacuum vessel, a saucer placed in the vacuum vessel, on which a sampling tube for containing a gas to be measured is placed, and placed on the saucer. The gas analyzer according to claim 1, further comprising: a heater unit that heats the sampling tube; and an elevating mechanism that moves the tray up and down to the electronic balance. A gas supply mechanism for pulsing the gas to be measured, a buffer tank disposed downstream of the gas supply mechanism, and a quadrupole mass having an ion source disposed downstream of the buffer tank The gas analyzer according to claim 1, further comprising: an analyzer; and an orifice plate for allowing a part of the gas to be measured to flow into the ion source of the quadrupole mass spectrometer from the gas supply mechanism. . The gas supply mechanism includes a primary storage container that is connected to the buffer tank and temporarily stores a part of the gas to be measured, and a plurality of on-off valves that open and close the primary storage container. The gas analyzer according to claim 4. 6. The gas analyzer according to claim 4, wherein a cooling means for cooling a pipe through which the gas to be measured flows is disposed between the gas supply mechanism and the heating means. The gas analyzer according to claim 1, wherein the heating unit is an electric furnace, or at least one of an electric furnace and high-frequency heating, laser heating, and a halogen lamp. The gas analyzer according to claim 4, wherein an evacuation device is connected to the quadrupole mass spectrometer. The gas analyzer according to claim 5, wherein a ratio of an internal volume of the temporary storage container to the buffer tank is 1/10000 to 1/400.

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