JP7440595B1 - Gas analysis conduit - Google Patents

Abstract

The present invention provides a gas analysis conduit that has excellent flexibility, is easy to handle, and is applicable to component analysis of high-purity gas. [Solution] It has a double pipe structure including a first conduit 2 made of resin and a second conduit 3 made of resin, and the second conduit 3 is located inside the first conduit 2. The base end 2a communicates with the supply port, the base end 3a of the second conduit 3 opens inside the first conduit 2, the distal end 3b of the second conduit 3 communicates with the gas analyzer, and the distal end 3b of the second conduit 3 communicates with the gas analyzer. The gas analysis conduit 1 having the opening 2b outside the second conduit 3 is selected. [Selection diagram] Figure 1

Description

The present invention relates to gas analysis conduits.

Liquefied gas such as liquefied nitrogen is filled into a tank truck from a liquefied gas filling facility and then transported to a consumer. Specifically, a tank truck is filled with liquefied gas, and then the liquefied gas in the tank truck is supplied to a gas analyzer to measure the concentration of impurities (moisture and oxygen in the case of liquefied nitrogen) in the liquefied gas. do. After confirming that the concentration of impurities in the liquefied gas is within a specified value, the liquefied gas is shipped as a product gas. Conventionally, when supplying gas from a tank truck to a gas analyzer, a gas conduit made of metal such as stainless steel (SUS), which is suitable for analyzing high-purity gases, has been used.

Here, the base end of the gas conduit used for gas analysis (gas analysis conduit) is connected to the gas analyzer. When the tank truck is not filled with liquefied gas, the tip of the gas analysis conduit is connected to the filling equipment side, and the gas flow path within the gas analysis conduit is constantly purged with vaporized liquefied gas. On the other hand, when analyzing the liquefied gas (product liquefied gas) in the tank truck, the tip of the gas analysis conduit is removed from the filling equipment and connected to the tank truck. Thereby, the liquefied gas filled in the tank truck is introduced into the gas analyzer via the gas conduit.

By the way, the gas pipe connected to the gas analyzer requires a certain length so that it can be used even when the connection location on the tank truck side differs depending on the vehicle. Furthermore, since the gas analysis conduit is moved and accommodated when connected to the filling equipment side while gas analysis is not being performed, the gas analysis conduit is required to have flexibility.

However, due to the characteristics of the metal, conventional metal gas analysis conduits retain their shape when stored, making them difficult to handle and difficult to position where they connect to tank trucks. . Furthermore, since the metal gas analysis conduit is hard, there is a risk of damaging the connection part on the tank truck side when it comes into contact with the metal conduit.

Therefore, Patent Document 1 discloses a gas analysis conduit made of resin. The gas analysis conduit disclosed in Patent Document 1 has a double tube structure consisting of an inner tube and an outer tube made of resin, and the base end of the inner tube is connected to the gas supply side, and the base end of the outer tube is connected to the gas supply side. The tip is connected to the gas analyzer side. The tip of the inner tube opens inside the outer tube, and part of the gas to be analyzed led out from the tip of the inner tube is supplied as a sealing gas to the space between the outer tube and the inner tube, and the remaining is supplied to the gas analyzer as analysis gas.

Patent No. 2607208

However, in the gas analyzer conduit disclosed in Patent Document 1, the seal gas and the analysis gas are separated on the gas analyzer side rather than on the gas supply side, but there is a problem in that it is difficult to control the flow rates of each gas. there were. In addition, the flow direction of the gas flowing through the inner tube and the flow direction of the gas flowing as seal gas into the space between the outer tube and the inner tube are opposite, resulting in insufficient supply of seal gas and high purity. The problem was that it was not suitable for gas component analysis.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas analysis conduit that has excellent flexibility, is easy to handle, and is applicable to component analysis of high-purity gas. .

In order to solve the above problems, the present invention includes the following configuration.
[1] A gas conduit for gas analysis located between a gas supply port to be analyzed and a gas analyzer,
It has a double pipe structure including a first conduit made of resin and a second conduit made of resin, and the second conduit is located inside the first conduit,
a proximal end of the first conduit communicates with the supply port;
The base end of the second conduit opens inside the first conduit at a position closer to the gas analyzer than the base end of the first conduit,
a tip of the second conduit communicates with the gas analyzer,
A conduit for gas analysis, wherein a distal end of the first conduit opens to the outside of the second conduit at a position closer to the gas analyzer.
[2] The proximal end of the first conduit is the introduction port of the gas analysis conduit,
The gas analysis conduit according to [1], wherein the tip of the second conduit is an outlet of the gas analysis conduit.
[3] Among the channels inside the first conduit,
The inside of the second conduit is a flow path for an analysis gas,
The gas analysis conduit according to [1] or [3], wherein the space between the first conduit and the second conduit is a sealing gas flow path.
[4] The gas analysis conduit according to any one of [1] to [3], wherein the analysis gas and the sealing gas flow in the same direction.
[5] A positioning member that supports the second conduit in the first conduit in a space between the first conduit and the second conduit with the first conduit and the second conduit separated from each other. The gas analysis conduit according to any one of [1] to [4], comprising:
[6] The gas analysis conduit according to any one of [1] to [5], wherein the positioning member is located near the proximal end of the second conduit.
[7] At least one of the first conduit and the second conduit uses a resin tube with a moisture (H ₂ O) permeation rate of 50 [mg/m/day] or less, [1] to [6] ] The gas analysis conduit according to any one of the above.
[8] At least one of the first conduit and the second conduit uses a resin tube having a helium (He) gas permeation rate of 6×10 ⁻⁷ [Pa·m ³ /sec/100 mm] or less. , [1] to [7].
[9] A gas conduit for gas analysis located between the supply port of the gas to be analyzed and the gas analyzer,
A first conduit made of resin, a second conduit made of resin, and a third conduit made of resin are provided, the second conduit is located inside the first conduit, and the second conduit is located inside the second conduit. It has a triple pipe structure in which three conduits are located,
a proximal end of the first conduit communicates with the supply port;
The base end of the second conduit opens inside the first conduit at a position closer to the gas analyzer than the base end of the first conduit,
The base end of the third conduit opens inside the second conduit at a position closer to the gas analyzer than the base end of the first conduit,
a tip of the third conduit communicates with the gas analyzer,
The tip of the second conduit opens to the outside of the third conduit at a position closer to the gas analyzer,
A conduit for gas analysis, wherein a distal end of the first conduit opens to the outside of the second conduit at a position closer to the gas analyzer.

The gas analysis conduit of the present invention has excellent flexibility, is easy to handle, and can be applied to component analysis of high-purity gas.

FIG. 1 is a cross-sectional view showing the configuration of a gas analysis conduit according to an embodiment of the present invention. 2 is a sectional view taken along line A-A' shown in FIG. 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating an example of how a gas analysis conduit is used, which is an embodiment of the present invention. FIG. 3 is a sectional view showing the configuration of a gas analysis conduit according to another embodiment of the present invention. 5 is a sectional view taken along line B-B' shown in FIG. 4. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of the conduit for gas analysis which is one Embodiment to which this invention is applied is demonstrated in detail using drawing. Note that the drawings used in the following explanations may show characteristic parts enlarged for convenience in order to make the characteristics easier to understand, and the dimensional ratio of each component may not be the same as the actual one. do not have.

<Gas analysis conduit>
First, as one embodiment of the present invention, a gas analysis conduit 1 shown in FIGS. 1 to 3, for example, will be described. Here, FIG. 1 is a sectional view showing an example of the configuration of a gas analysis conduit 1. As shown in FIG. FIG. 2 is a cross-sectional view taken along line AA' shown in FIG. FIG. 3 is a schematic diagram illustrating an example of how the gas analysis conduit 1 is used.

As shown in FIG. 1, the gas analysis conduit 1 of this embodiment includes a first conduit 2 made of resin and a second conduit 3 made of resin. It has a double tube structure in which the tubes 3 are positioned coaxially. The gas analysis conduit 1 of this embodiment is a gas analysis conduit located between a supply port for a gas to be analyzed and a gas analyzer. Specifically, the length of the gas analysis conduit 1 can be 1 to 15 m, preferably 5 to 10 m.

As shown in FIGS. 1 and 2, the first conduit 2 is a resin tube located at the outermost surface of the gas analysis conduit 1 and forms the outer layer.

The length of the first conduit 2 is not particularly limited as long as it is possible to connect the supply port of the gas to be analyzed and the gas analyzer.

The outer diameter, inner diameter, and thickness (wall thickness) of the first conduit 2 are such that the gas analysis conduit 1 exhibits the necessary mechanical properties (bending strength, elasticity, etc.) to exhibit sufficient flexibility, and It exhibits gas barrier properties against components contained in the atmosphere (air) that are measurement impurities for the target gas (e.g., water, oxygen, carbon dioxide, nitrogen, argon, etc.), and also has a second conduit 3 inside. There is no particular limitation as long as it can be inserted.

Specifically, the outer diameter of the first conduit 2 can be 5 to 15 mm, preferably 8 to 12 mm. Here, by setting the outer diameter of the first conduit 2 to 5 mm or more, a sufficient space can be secured inside the first conduit 2 for the second conduit 3 to be inserted therethrough. On the other hand, by setting the outer diameter of the first conduit 2 to 15 mm or less, mechanical properties (bending strength, elasticity, etc.) necessary for exhibiting sufficient flexibility can be maintained.

Further, the inner diameter of the first conduit 2 may be 3 to 12 mm, preferably 6 to 10 mm. Here, by setting the inner diameter of the first conduit 2 to 3 mm or more, a sufficient space can be secured inside the first conduit 2 for the second conduit 3 to be inserted therethrough. On the other hand, by setting the inner diameter of the first conduit 2 to 12 mm or less, the amount of gas used for analysis can be reduced while ensuring a flow path cross-sectional area.

Further, the thickness (thickness) of the first conduit 2 can be 0.3 to 3 mm, preferably 0.5 to 1.5 mm. Here, by setting the thickness of the first conduit 2 to 0.3 mm or more, it is possible to exhibit gas barrier properties against components contained in the atmosphere that become measurement impurities for the gas to be analyzed. On the other hand, by setting the thickness of the first conduit 2 to 3 mm or less, it is possible to exhibit mechanical properties (bending strength, elasticity, etc.) necessary for exhibiting sufficient flexibility.

Note that as the first conduit 2, from the viewpoint of easy availability, it is more preferable to use a resin tube having an outer diameter of 10 mm, an inner diameter of 8 mm, and a thickness (wall thickness) of 1 mm.

The material of the resin tube constituting the first conduit 2 is not particularly limited, and can be appropriately selected depending on the type of gas to be analyzed. For example, when the gas to be analyzed is nitrogen, it is preferable to use a resin having moisture barrier properties with a moisture (H ₂ O) permeation rate of 50 [mg/m/day] or less as the material of the resin tube. . Note that the permeation rate of water (H ₂ O) can be measured by a general measurement method such as an isobaric method or a differential pressure method.

Examples of resins having moisture barrier properties include tetrafluoroethylene/hexafluoropropylene copolymer (FEP), tetrafluoroethylene/perfluoroether copolymer (PFA), polyvinylidene fluoride (PVDF), and polychlorotrifluoroethylene. (PCTFE), ethylene/chlorotrifluoroethylene copolymer (ECTFE), polytetrafluoroethylene (PTFE), ethylene/tetrafluoroethylene copolymer (ETFE), and the like. Among these, it is preferable to use a resin tube made of tetrafluoroethylene/hexafluoropropylene copolymer (FEP) as the first conduit 2 from the viewpoint of blocking moisture.

As shown in FIGS. 1 and 2, the second conduit 3 is a resin tube that forms an inner layer and is located in the space inside the first conduit 2 and is arranged coaxially with the first conduit 2. be.

The length of the second conduit 3 is not particularly limited as long as it is possible to connect the supply port of the gas to be analyzed and the gas analyzer.

The outer diameter, inner diameter, and thickness (wall thickness) of the second conduit 3 are such that the gas analysis conduit 1 exhibits the necessary mechanical properties (bending strength, elasticity, etc.) to exhibit sufficient flexibility, and It exhibits gas barrier properties against components contained in the atmosphere (air) that are measurement impurities for the target gas (e.g., water, oxygen, carbon dioxide, nitrogen, argon, etc.), and also provides a gas barrier for the target gas to be analyzed. There is no particular limitation as long as the gas can be passed through at a sufficient flow rate.

Specifically, the outer diameter of the second conduit 3 can be 1 to 11 mm, preferably 4 to 8 mm. Here, by setting the outer diameter of the second conduit 3 to 1 mm or more, a sufficient flow path for the gas to be analyzed can be secured inside the second conduit 3. On the other hand, by setting the outer diameter of the second conduit 3 to 11 mm or less, it can be inserted into the inside of the first conduit 2.

Further, the inner diameter of the second conduit 3 can be 0.5 to 8 mm, preferably 2 to 6 mm. Here, by setting the inner diameter of the second conduit 3 to 0.5 mm or more, a sufficient flow path for the gas to be analyzed can be secured inside the second conduit 3. On the other hand, by setting the inner diameter of the second conduit 3 to 8 mm or less, the amount of gas used for analysis can be reduced while ensuring a flow path cross-sectional area.

Further, the thickness (thickness) of the second conduit 3 can be 0.3 to 3 mm, preferably 0.5 to 1.5 mm. Here, by setting the thickness of the second conduit 3 to 0.3 mm or more, it is possible to exhibit gas barrier properties against components contained in the atmosphere that become measurement impurities for the gas to be analyzed. On the other hand, by setting the thickness of the second conduit 3 to 3 mm or less, it is possible to exhibit mechanical properties (bending strength, elasticity, etc.) necessary for exhibiting sufficient flexibility.

In addition, from the viewpoint of easy availability, it is more preferable to use a resin tube having an outer diameter of 6 mm, an inner diameter of 4 mm, and a thickness (thickness) of 1 mm as the second conduit 3.

The material of the resin tube constituting the second conduit 3 is not particularly limited, and can be appropriately selected depending on the type of gas to be analyzed. For example, if the gas to be analyzed is nitrogen, the material for the resin tube should have oxygen barrier properties with a helium (He) gas permeation rate of 6×10 ⁻⁷ [Pa・m ³ /sec/100 mm] or less. It is preferable to use a resin having Note that the amount of permeation of helium (He) can be measured by a general measurement method such as an isobaric method or a differential pressure method.

By the way, impurities contained in the gas to be analyzed flowing inside the second conduit 3 include main components of the atmosphere such as oxygen, components that exist in trace amounts in the atmosphere (for example, carbon dioxide, etc.), and tank trucks installed. The main components are those that exist in the atmosphere due to the location. Furthermore, during gas analysis, the types and concentrations of these impurities may change.

Therefore, the inventors of the present application believe that the permeability of impurities into the analytical conduit according to the present invention can be determined by the permeability of helium, which has a relatively small molecular diameter and is also used in leak tests. It has been found that the objects of the present invention can be achieved regardless of the type.

Therefore, as described above, the amount of helium (He) gas permeation through the second conduit 3 can be used to specify the oxygen barrier properties of the second conduit 3.

Examples of resins having oxygen barrier properties include copolymers of tetrafluoroethylene and ethylene (EPFE), tetrafluoroethylene/hexafluoropropylene copolymers (FEP), and tetrafluoroethylene/perfluoroether copolymers (PFA). , polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene/chlorotrifluoroethylene copolymer (ECTFE), polytetrafluoroethylene (PTFE), ethylene/tetrafluoroethylene copolymer (ETFE) etc. Among these, it is preferable to use a resin tube made of a copolymer of tetrafluoroethylene and ethylene (EPFE) as the second conduit 3 from the viewpoint of gas interruption.

As shown in FIGS. 1 and 3, the gas analysis conduit 1 of this embodiment has a supply port for the gas to be analyzed (specifically, for example, It is connected to the connection port T ₀ ) of the tank truck T shown in FIG. A gas joint (not shown) may be provided at the base end 1A of the gas analysis conduit 1.

As a result, the base end 2a of the first conduit 2 is communicated with the gas supply port via the gas joint located at the base end 1A of the gas analysis conduit 1, and the gas to be analyzed is supplied to the inside of the first conduit 2. will be introduced in That is, in the gas analysis conduit 1 of this embodiment, the base end 2a of the first conduit 2 is an inlet for the gas to be analyzed.

Further, as shown in FIG. 1, in the gas analysis conduit 1, the proximal end 3a of the second conduit 3 is located inside the first conduit 2 from the proximal end 2a of the first conduit 2 at a position closer to the proximal end 1A. It opens inside the first conduit 2 at the position where it enters (that is, the position closer to the gas analyzer).

According to the gas analysis conduit 1 of this embodiment, as shown in FIG. 2, the second conduit 3 is arranged in the space inside the first conduit 2 so as to be coaxial with the first conduit 2. As a result, at the base end 1A of the gas analysis conduit 1, the flow path of the gas to be analyzed introduced inside the second conduit 3 is connected to the space 3A inside the second conduit 3 and the first conduit 2. It branches into a space 2A between the second conduit 3 and the second conduit 3.

Here, in the gas analysis conduit 1, when the first conduit 2 and the second conduit 3 are coaxial, the distance L between the inner circumferential surface of the first conduit 2 and the outer circumferential surface of the second conduit 3 is It is calculated as shown in Equation A below.
(Distance L) = (Inner diameter of first conduit 2 - Outer diameter of second conduit 3) ÷ 2 ... Formula A

The distance L is not particularly limited, and can be appropriately selected depending on the flow rate of gas flowing through the space 2A between the first conduit 2 and the second conduit 3. The distance L can be 0.1 to 2 mm, preferably 0.5 to 1.5 mm. Here, by setting the distance L to 0.1 mm or more, a sufficient flow passage cross-sectional area of the space 3A can be ensured. On the other hand, by setting the distance L to 2 mm or less, the amount of gas flowing into the flow path can be reduced.

According to the gas analysis conduit 1 of the present embodiment, the distance L between the inner circumferential surface of the first conduit 2 and the outer circumferential surface of the second conduit 3 is preferably uniform in the circumferential direction. Therefore, in the space 2A between the first conduit 2 and the second conduit 3, a plurality of positioning members 5 are arranged at intervals along the circumferential direction of the outer peripheral surface of the second conduit 3. It is preferable. Thereby, the second conduit 3 can be supported within the first conduit 2 with the first conduit 2 and the second conduit 3 separated by the distance L. That is, in the gas analysis conduit 1, the second conduit 3 can be arranged in a space inside the first conduit 2 so as to be coaxial with the first conduit 2.

The positioning member 5 is located on the entrance side of the space 2A between the first conduit 2 and the second conduit 3 in the length direction (axial direction) of the gas analysis conduit 1, that is, near the proximal end 3a of the second conduit 3. It is preferable to be located at . Thereby, as shown in FIG. 2, in the first conduit 2, the opening of the space 2A (gas inlet) and the opening of the space 3A (gas inlet) can be sufficiently secured. Note that the positioning member 5 may be provided continuously or intermittently on the outer peripheral surface of the second conduit 3 over the entire length of the second conduit 3.

The positioning member 5 can support the second conduit 3 within the first conduit 2 with the first conduit 2 and the second conduit 3 separated from each other, and may be made of a material that does not corrode by the gas to be analyzed. , not particularly limited. As the positioning member 5, for example, a metal column whose outer diameter is the distance L can be used. Further, the number of positioning members 5 is preferably 3 or more and 6 or less, more preferably 3 or 4.

As shown in FIGS. 1 and 3, the gas analysis conduit 1 of this embodiment has a gas analyzer (for example, a filling equipment S shown in FIG. S1).
Specifically, at the distal end 1B of the gas analysis conduit 1, the distal end 3b of the second conduit 3 and the distal end 2b of the first conduit 2 are located. Gas joints (not shown) may be provided at the distal end 3b of the second conduit 3 and the distal end 2b of the first conduit 2, respectively. Thereby, the gas flowing through the space 2A and the gas flowing through the space 3A can be separately led out.

The tip 3b of the second conduit 3 is communicated with the gas analyzer S1 of the gas analyzer via a gas joint (not shown), and the gas led out from the space 3A inside the second conduit 3 is used as an analysis gas for gas analysis. A total of S1 is supplied. That is, in the gas analysis conduit 1 of this embodiment, the space 3A inside the second conduit 3 is a flow path for the analysis gas, and the tip 3b of the second conduit 3 is an outlet for the analysis gas.

Further, as shown in FIG. 1, in the gas analysis conduit 1, at the distal end 1B, the distal end 2b of the first conduit 2 opens to the outside of the second conduit 3 at a position closer to the gas analyzer, and there is a space. The gas derived from 2A is derived as a seal gas. That is, in the gas analysis conduit 1 of this embodiment, the space 2A between the first conduit 2 and the second conduit 3 is a flow path for seal gas, and the tip 2b of the first conduit 2 is an outlet for barge gas. be. In addition, in the gas analysis conduit 1 of this embodiment, the tip 2b of the first conduit 2 is connected to the flowmeter S2.

According to the gas analysis conduit 1 of this embodiment, as shown in FIG. 1, a part of the gas to be analyzed is used as an analysis gas and the remainder is used as a seal gas, and the second conduit serves as a flow path for the analysis gas. Seal gas can be circulated in the space 2A outside of 3. Therefore, even if the resin tubes used as the first conduit 2 and the second conduit 3 do not have sufficient gas barrier properties against all components that become measurement impurities for the gas to be analyzed, the gas analysis of this embodiment The conduit 1 can be applied to component analysis of high-purity gas.

Further, according to the gas analysis conduit 1 of this embodiment, on the proximal end 1A side, the flow path in the first conduit 2 is the analysis gas flow path (space 3A) and the seal gas flow path (space 2A). Therefore, the analysis gas and the seal gas flow in the same direction. Therefore, by simply supplying the gas to be analyzed into the first conduit 2, the seal gas can be made to flow through the seal gas flow path (space 2A) without providing any additional equipment.

Here, the flow rate ratio of the analysis gas and the sealing gas can be adjusted by the ratio of their respective flow path cross-sectional areas. The flow path cross-sectional area SA of the analysis gas and the flow path cross-sectional area SB of the seal gas are calculated by the following formulas B and C, respectively.
(Flow path cross-sectional area SA) = 3.14 x (inner diameter of second conduit 3/2) ² ...Formula B
(Flow path cross-sectional area SB) = 3.14 x [(inner diameter of first flow path 2/2) ² - (outer diameter of second flow path 3/2) ² ]...Formula C

The flow rate ratio of the analysis gas and the sealing gas is not particularly limited, and can be appropriately selected depending on the gas barrier properties of the resin tube and the ease with which impurities can be removed. The flow rate ratio (analysis gas: sealing gas) can be 2:1 to 2:5, preferably 2:1 to 2:2. Here, by increasing the flow rate ratio of the seal gas to the analysis gas, it becomes possible to analyze product gas with higher purity. On the other hand, in the analysis of a product gas with relatively low purity, the analysis can be performed even if the flow rate ratio of the seal gas to the analysis gas is reduced, and the seal gas necessary for the analysis can be saved.

As shown in FIG. 3, in the gas analysis conduit 1 of this embodiment, the base end 3b of the second conduit 3 is connected to the gas analyzer S1 at the distal end 1B. When the tank truck T is not filled with the gas to be analyzed, the base end 1A of the gas analysis conduit 1 is connected to the analysis equipment S side, and the gas flow path in the gas analysis conduit 1 is filled with the gas to be analyzed. It is constantly purged with gas. On the other hand, when analyzing the liquefied gas (product gas) in the tank truck T, the base end 1A of the gas analysis conduit 1 is removed from the filling equipment S side and connected to the tank truck T side. Thereby, the liquefied gas filled in the tank truck T can be introduced into the gas analyzer S1 via the second conduit 3 of the gas analysis conduit 1, and the components of the liquefied gas (product gas) can be analyzed.

By the way, low-temperature gas obtained by vaporizing a portion of liquefied gas is introduced into the gas analysis conduit as the gas to be analyzed. Therefore, the outer periphery (the outermost surface) of the gas analysis conduit undergoes repeated icing and deicing every time a gas analysis is performed. Furthermore, since gas analysis conduits are often used outdoors, the gas analysis conduits themselves are often exposed to rain and snow. As described above, gas analysis conduits are generally used in environments where they are exposed to moisture (water) in a wide range of concentrations (underwater, 100% concentration, dry air, etc.).

Therefore, according to the gas analysis conduit 1 of this embodiment, since a resin conduit having moisture barrier properties is used as the first conduit 2 serving as the outer layer, the gas composition in the seal gas flow path (space 2A) is stabilized. This enables more stable gas analysis.

Furthermore, according to the gas analysis conduit 1 of the present embodiment, the outer layer (first conduit 2) having moisture barrier properties can minimize the intrusion of moisture into the seal gas flow path (space 2A). can. As a result, in the gas analysis conduit 1 of the present embodiment, a resin conduit mainly focused on the barrier properties against impurity gases present in a certain amount in the atmosphere can be used as the inner layer (second conduit 3).

That is, considering the environment in which it will be used, the outer layer is a resin conduit (first conduit 2) that has moisture barrier properties, and the inner layer is a resin conduit (second conduit 3) that has barrier properties for impurity gases present in the atmosphere. ), gas analysis conduit 1 that more satisfies the objectives of the present invention can be obtained by using resin piping having different properties.

On the other hand, when analyzing the components of the gas to be analyzed using the gas analysis conduit 1 of this embodiment, in order to keep the analysis conditions constant, the flow rate of the seal gas in the seal gas flow path (space 2A) is needs to be constant.

Therefore, in the conventional gas analysis conduit disclosed in the above-mentioned Patent Document 1, in which the analysis gas and the seal gas flow in a counterflow, the exhaust hole 17a shown in FIG. 1 of Patent Document 1 is It was necessary to install a seal gas flow meter in that area. In this case, the operation of the analysis equipment for the gas to be analyzed and the confirmation of the seal gas flow rate are performed in different places, and there is room for improvement in the efficiency of the analysis work.

On the other hand, according to the gas analysis conduit 1 of the present embodiment, since a flow meter can be installed at the tip 2b of the first conduit 2, the flow rate of the seal gas can be measured on the spot at the same time as the analysis equipment S is operated. You can check it. That is, there is no need to move to check the seal gas flow rate, and the efficiency of analysis work can be improved.

As explained above, the gas analysis conduit 1 of this embodiment has a double pipe structure consisting of the first conduit 2 and the second conduit 3 made of resin, so it has excellent flexibility and Even if it is long, it can be easily rolled up and stored, and there is no residue left after folding, making it easy to handle. Moreover, according to the gas analysis conduit 1 of this embodiment, since it is made of resin, even if it comes into contact with the filling equipment S or the tank truck T, it will not damage them.

Further, according to the gas analysis conduit 1 of the present embodiment, a part of the gas to be analyzed is used as the analysis gas, and the remainder is used as the seal gas, and the space outside the second conduit 3 that becomes the flow path for the analysis gas is used. Since seal gas can be passed through 3A, it can be applied to component analysis of high purity gas.

For example, when the gas to be analyzed is high-purity liquefied nitrogen, a resin tube with high moisture barrier properties is used as the first conduit 2, which is the outer layer, and a resin tube with high oxygen barrier properties is used as the second conduit 3, which is the inner layer. By using this method, more accurate component analysis can be performed without being affected by impurities from the atmosphere.

Note that the technical scope of the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit of the present invention.
For example, in the gas analysis conduit 1 of the embodiment described above, the case where the gas to be analyzed is high-purity liquefied nitrogen has been described as an example, but the present invention is not limited to this. According to the gas analysis conduit of the present invention, impurities may penetrate into the analysis gas from the atmosphere of the installed environment through the resin first conduit 2 and the second conduit, thereby affecting the measurement results. It can be applied to all gas analyzes with different characteristics. Specifically, depending on the concentration of multiple impurities in the gas to be analyzed, by selecting the types of resin outer and inner tubes that have different permeation characteristics (gas barrier properties) for each impurity, the influence of impurity permeation can be investigated. can be effectively reduced. Furthermore, it is useful for analyzing product gases for industrial, medical, and semiconductor applications that require high purity, which requires preventing the entry of trace amounts of impurities mainly present in the air.

Furthermore, in the gas analysis conduit 1 of the embodiment described above, when the gas to be analyzed is high-purity liquefied nitrogen, the first conduit 2 serving as the outer layer has moisture barrier properties, and the second conduit 3 serving as the inner layer has moisture barrier properties. Although the structure in which the structure has oxygen barrier properties has been described as an example, the present invention is not limited thereto. For example, the first conduit 2 serving as the outer layer may have oxygen barrier properties, and the second conduit 3 serving as the inner layer may have moisture barrier properties. Further, both the first conduit 2 and the second conduit 3 may have moisture barrier properties or oxygen barrier properties. Alternatively, one of the first conduit 2 and the second conduit 3 may have gas barrier properties. Furthermore, one of the first conduit 2 and the second conduit 3 may be configured to have functions other than gas barrier properties (mechanical properties, weather resistance, abrasion resistance, etc.).

Moreover, according to the gas analysis conduit 1 of the embodiment described above, the configuration having a double pipe structure including the first conduit 2 and the second conduit has been described as an example, but the present invention is not limited to this. For example, as shown in FIGS. 4 and 5, it includes a first conduit 22 made of resin as an outer layer, a second conduit 23 made of resin as an intermediate layer, and a third conduit 24 made of resin as an inner layer. The gas analysis conduit 21 may have a triple pipe structure in which the second conduit 23 is located inside the first conduit 22 and the third conduit 24 is located inside the second conduit 23. This gas analysis conduit 21, like the gas analysis conduit 1 of the embodiment described above, can be used as a gas analysis gas conduit located between the gas analyzer supply port and the gas analyzer. can.

As shown in FIGS. 4 and 5, in the gas analysis conduit 21, on the proximal side, the proximal end of the first conduit 22 serving as the outer layer communicates with the supply port of the gas to be analyzed, and the proximal end of the first conduit 22 serving as the outer layer communicates with the supply port of the gas to be analyzed, and the first conduit serving as the intermediate layer The base end of the second conduit 23 opens inside the first conduit 22 at a position inside the base end of the first conduit 22, and the base end of the third conduit 24 opens inside the base end of the first conduit 22. It also opens inside the second conduit 23 at the position where the second conduit 23 enters the inside.

On the distal end side of the gas analysis conduit 21, the distal end of the third conduit 24 serving as the inner layer communicates with the gas analyzer, and the distal end of the second conduit 23 serving as the inner layer opens to the outside of the third conduit 24. The tip of the first conduit 22 serving as the outer layer opens to the outside of the second conduit 23 .

Thereby, according to the gas analysis conduit 21, the space 24A inside the third conduit 24 serving as the inner layer is the flow path for the analysis gas, and the second conduit located outside the flow path for the analysis gas A space 23A between the third conduit 23 and the third conduit 24 and a space 22A between the first conduit 22 and the second conduit 23 serve as sealing gas flow paths.

According to the gas analysis conduit 21, in the analysis of impurities in ultra-high purity gas, even when the measurement limit of analyzers on the market is close to that of the analyzer, that is, when even the slightest impurity from the outside cannot be allowed to pass through. Since it has a triple-pipe structure in which the sealing gas flow path is provided twice outside the analysis gas flow path, the influence of gas permeation through the gas analysis conduit can be reduced to a limitless extent.

Furthermore, according to the gas analysis conduit 21, similar to the gas analysis conduit 1 of the embodiment described above, by selecting the gas barrier properties of the resin tubes constituting the outer layer, intermediate layer, and inner layer, various types of ultra-high purity can be obtained. It can be applied to impurity analysis in gas.

As the gas analysis conduit 21 having a triple tube structure, from the viewpoint of easy availability, the first conduit 22 serving as the outer layer is a resin tube with an outer diameter of 14 mm, an inner diameter of 12 mm, and a thickness (thickness) of 1 mm. The second conduit 23 serving as the intermediate layer is a resin tube with outer diameter: 10 mm, inner diameter: 8 mm, and thickness (wall thickness): 1 mm.The third conduit 24 serving as the inner layer has outer diameter: 6 mm, inner diameter: 4 mm, and thickness. Thickness (thickness): It is preferable to use resin tubes each having a thickness of 1 mm.

1, 21 Gas analysis conduit 1A base end 1B distal end 2 first conduit 2A space 2a proximal end 2b distal end 3... second conduit 3A space 3a proximal end 3b distal end 5... positioning member

Claims (9)

A gas conduit for gas analysis located between a gas supply port to be analyzed and a gas analyzer,
It has a double pipe structure including a first conduit made of resin and a second conduit made of resin, and the second conduit is located inside the first conduit,
a proximal end of the first conduit communicates with the supply port;
A proximal end of the second conduit opens inside the first conduit,
The base end of the second conduit is located inside the first conduit and on the gas analyzer side,
a tip of the second conduit communicates with the gas analyzer,
The tip of the first conduit opens to the outside of the second conduit,
The first conduit and the second conduit have flexibility, and at least one of these conduits has gas barrier properties against impurities in the gas to be analyzed ;
A conduit for gas analysis , characterized in that gases flowing through the first conduit and the second conduit have the same composition . The proximal end of the first conduit is an inlet of the gas analysis conduit,
The gas analysis conduit according to claim 1, wherein the tip of the second conduit is an outlet of the gas analysis conduit. Of the flow path inside the first conduit,
The inside of the second conduit is a flow path for an analysis gas,
The gas analysis conduit according to claim 1, wherein a space between the first conduit and the second conduit is a flow path for seal gas. The gas analysis conduit according to claim 3, wherein the analysis gas and the sealing gas flow in the same direction. a positioning member in a space between the first conduit and the second conduit, supporting the second conduit within the first conduit with the first conduit and the second conduit separated; The gas analysis conduit according to claim 1. The gas analysis conduit according to claim 5, wherein the positioning member is located near the proximal end of the second conduit. Any one of claims 1 to 6, wherein at least one of the first conduit and the second conduit uses a resin tube having a moisture (H ₂ O) permeation rate of 50 [mg/m/day] or less. Conduit for gas analysis as described in Section. At least one of the first conduit and the second conduit is a resin tube having a helium (He) gas permeation rate of 6×10 ⁻⁷ [Pa·m ³ /sec/100 mm] or less. 7. The gas analysis conduit according to any one of 1 to 6. A gas conduit for gas analysis located between a gas supply port to be analyzed and a gas analyzer,
A first conduit made of resin, a second conduit made of resin, and a third conduit made of resin, the second conduit is located inside the first conduit, and the second conduit is located inside the second conduit. It has a triple pipe structure in which three conduits are located,
a proximal end of the first conduit communicates with the supply port;
A proximal end of the second conduit opens inside the first conduit,
The base end of the second conduit is located inside the first conduit and on the gas analyzer side,
A proximal end of the third conduit opens inside the second conduit,
a tip of the third conduit communicates with the gas analyzer,
The tip of the second conduit opens to the outside of the third conduit,
The tip of the first conduit opens to the outside of the second conduit,
The first conduit, the second conduit, and the third conduit have flexibility, and at least one of these conduits has gas barrier properties against impurities in the gas to be analyzed;
A conduit for gas analysis , characterized in that gases flowing through the first conduit and the second conduit have the same composition .

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