JP2005083892A - Specimen introduction device with sample tube heating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a specimen introduction device with a sample tube heating system for reducing the effect of a seal member. <P>SOLUTION: A heating part 2 is equipped with a sample tube insertion part 6 for thereinto inserting a sample tube 10 and mounted with a chamber 8 along its inner wall. One end 8a thereof on the sample tube insertion side projects from an end face of the heating part 2. The heating part 2 heats the sample tube 10 via the chamber 8. A pipe 4 for specimen introduction is connected to the other side (the opposite side of the sample tube insertion side) of the heating part 2 for introducing specimen constituents desorbed by the sample tube 10 into an analysis part. The sample tube 10 and the pipe 4 are connected to each other at a connection part A in the interior of the insertion part. Since an O-ring 15 for sealing up a gap between the sample tube 10 and the chamber 8 is disposed at a position preventing direct contact with the heating part 2, heating temperature for the sample tube 10 is kept from being affected by the specification temperature of the O-ring 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for introducing a sample into an analyzer that handles a gaseous measurement target component such as a gas chromatograph (GC) or a gas chromatograph mass spectrometer (GC / MS). A structure (referred to as a sample tube) is placed in the atmosphere of the measurement target, the components contained in the atmosphere are adsorbed in the sample tube, the measurement target component is collected, and the measurement target component adsorbed in the sample tube The present invention relates to a sample introduction apparatus of a type in which a sample is desorbed and introduced into an analysis apparatus for analysis.

  One method for collecting analytical samples is to leave a sample tube filled with a highly adsorbable substance in a pipe made of glass or metal in the atmosphere of the gas to be measured for a certain period of time, and include it in the atmosphere. There is a method in which components are adsorbed in a sample tube, and the adsorbed components are subjected to analysis by bringing the sample tube back. When analyzing, the sample tube is heated at 300 ° C. to 350 ° C. with a dedicated autosampler to desorb components adsorbed inside, and an inert gas such as helium is flowed as a carrier gas from one of the sample tubes, The desorbed component is sent to the analyzer through the pipe along with the carrier gas. At this time, the piping from the sample tube to the analyzer is generally kept warm so that the sample does not re-adsorb before reaching the analyzer.

An elastomer O-ring, for example, is used as a seal member at the connection portion between the pipe for sending the sample to the analyzer and the sample tube. Although there is an upper limit of the temperature depending on the material specifications, when the temperature is raised to around the O-ring specification temperature, gas that interferes with analysis is generated from the O-ring, and this gas contains the component to be analyzed. If mixed in, accurate analysis becomes difficult.
In order to solve this problem, when the temperature only in the vicinity of the connection part is set to a low temperature (for example, if the specification temperature of the O-ring is 316 ° C. or lower), the temperature difference between the sample tube heating temperature and the connection part is large As a result, the periphery of the connection portion becomes a cold spot, and the sample component once desorbed from the sample tube may be re-adsorbed to this portion. In addition, although the pipe is coated with metal or glass, the material of the O-ring itself has larger irregularities than these surfaces, and the degree of adsorption is higher. The sample component that has been re-adsorbed around the connecting portion is mixed into the sample gas in the next analysis, which hinders analysis.

  Therefore, the present invention aims to reduce the influence of the seal member.

  The present invention includes a heating unit that heats a sample tube having a measurement component adsorbed therein, a carrier gas supply unit that is connected to one end of the sample tube and supplies a carrier gas into the sample tube, An introduction channel connected to the other end for introducing the measurement component detached from the sample tube to the analysis unit, heating the sample tube to desorb the measurement component adsorbed inside, and supplying the carrier gas to the carrier gas supply means A sample introduction apparatus of a sample tube heating system that guides a measurement component from the introduction flow path to the analysis unit by flowing the sample tube, wherein the heating means detachably inserts the sample tube with one end protruding. It has a sample tube insertion section that can be stored, and is located at the back of the sample tube insertion section. The sample introduction device is connected to the introduction flow path without passing through a sample member, and the sample introduction device has a gap between the sample tube inserted into the sample tube insertion portion and the heating means outside the heating member. A seal member for sealing on the peripheral surface on the one end side of the sample tube is provided.

  Moreover, you may further provide the carrier gas flow path which flows carrier gas in the direction of the said sealing member through the clearance gap between a sample tube and a heating means from the back part of a sample tube insertion part.

  Since the sample tube is connected to the introduction flow path at the back of the sample tube insertion part without going through the seal member, the heating temperature of the sample tube is not affected by the specification temperature of the seal member. The generation of spots can be prevented.

  If a carrier gas flow path for flowing a carrier gas in the direction of the seal member through the gap between the sample tube and the heating means from the back of the sample tube insertion portion is provided, the sample gas becomes a gas that hinders analysis. In addition to preventing contamination, the sample can also be prevented from leaking out of the system.

One embodiment will be described below.
FIG. 1 is a schematic longitudinal sectional view showing a sample introduction device of one embodiment together with a sample tube.
The sample introduction apparatus according to one embodiment includes a sample introduction pipe 4, a heating unit 2, a drive mechanism 7, and a stopper 20 from the analysis unit side (left side in the figure).

  The heating unit 2 includes a sample tube insertion unit 6 for inserting the sample tube 10 from one side, a chamber 8 is attached along the inner wall thereof, and one end 8a on the sample tube insertion side is an end surface of the heating unit 2 Than protruding. The heating unit 2 heats the sample tube 10 through the chamber 8. Connected to the other side of the heating unit 2 (the side opposite to the sample tube insertion side) is a sample introduction pipe 4 for introducing the sample component desorbed from the sample tube 10 into the analysis unit. The pipe 4 for connection is connected by the connection part A at the back of the sample tube insertion part.

The drive mechanism 7 can move in the horizontal direction and includes a connection mechanism 14 and a support portion 18 that supports the connection mechanism 14. The connection mechanism 14 also serves as a seal member and has a cylindrical hollow structure, in which the sample tube 10 and a carrier gas pipe 12 for supplying a carrier gas are joined. Reference numeral 16 denotes a joining member for joining the carrier gas pipe 12 having a diameter different from that of the sample tube 10 to the sample tube 10, and is integrated with the carrier gas pipe 12. The joining member 16 and the sample tube 10 can be joined and separated by sliding horizontally in the connection mechanism 14.
Reference numeral 15 denotes an O-ring provided in the connection mechanism 14. When the sample tube 10 is inserted into the sample tube insertion portion 6, the O-ring 15 is joined to the end face 8 a of the chamber 8 to prevent carrier gas leakage from the connection mechanism 14. At the same time, carrier gas leakage from the joint between the sample tube 10 and the joint member 16 is prevented.
Reference numeral 20 denotes a stopper for pushing out the member 16 from the opposite side of the sample tube 10 when the sample tube 10 is removed from the connection mechanism 14.

Next, the operation of the sample introduction apparatus of the present invention will be described with reference to FIGS.
2A and 2B are diagrams showing sample tube insertion, FIG. 2C shows sample component introduction, FIG. 2D shows sample tube removal, and FIG. 2E shows sample tube removal.

  (A) Insertion of the sample tube 10 into the heating unit 2 is such that the drive mechanism 7 moves in the direction of the heating unit 2 with one end of the sample tube 10 and one end of the member 16 inside the connection mechanism 14 joined. It is done by. As the drive means of the drive mechanism 7, for example, an existing drive means combining a feed screw, a motor, and a guide can be used. The member 16 is slidable inside the connection mechanism 14, but is not slid when the sample tube 10 is inserted due to a frictional force with the O-ring 15.

(B) When one end of the sample tube 10 (the side not in contact with the member 16) comes into contact with the innermost surface of the insertion portion 6 and the sample tube 10 stops, the drive mechanism 7 further moves to the heating portion 2 side. Thus, when the sample tube 10 and the member 16 slide in the connection mechanism 14 and the protruding portion 8a of the chamber 8 comes into contact with the O-ring 15, the movement of the drive mechanism 7 stops. At this time, the joint portion between the sample tube 10 and the member 16 is located in the middle of the O-ring 15 inside the connection mechanism 14, and therefore the inside of the connection mechanism 14 is sealed by the O-ring 15.
Further, since the sealing is performed when the protruding portion 8a of the chamber 8 comes into contact with the O-ring 15, an error in the length direction of the sample tube 10 can be ignored.

When the insertion of the sample tube 10 into the heating unit 2 is completed, the sample tube 10 is heated by the chamber 8, and when the temperature reaches a predetermined temperature, the carrier gas is sent from the pipe 12 as shown in (C). The heating unit 2 includes a temperature sensor (not shown), is made of a material having good thermal conductivity, and can be adjusted to a set temperature.
The heating temperature is not limited to the specification temperature of the O-ring because there is no O-ring inside the heating unit 2, and therefore, a cold spot cannot be made.
If the gas released from the O-ring 15 is emitted, a part of the sample gas flows between the sample tube 10 and the chamber 8 and is also released to the outside as a leak gas.

When the introduction of the sample gas into the analysis unit is completed, the drive mechanism 7 moves in the direction indicated by the arrow as shown in (D). The sample tube 10 is extracted from the heating unit 2 while being held by the joint 14 by the frictional force of the O-ring 15.
As shown in (E), when the connection mechanism 14 is returned to the initial position, one end of the member 16 comes into contact with the stopper 20 and is pushed into the connection means 14, so that the sample tube 10 is removed from the connection means 14. Extruded and removed.

  The sample tube 10 is held by the arm of the autosampler, and is set at an initial position when inserted into the heating unit 2. Further, even after the sample tube 10 is detached from the connection means 14, the sample tube 10 moves while being held by the arm.

FIG. 3 is an enlarged view showing in detail the connecting portion (portion corresponding to A in FIG. 1) where the sample tube 10 and the pipe 12 join in another embodiment.
In the portion A where the sample tube 10 and the pipe 12 are connected, other flow paths 24 and 26 are provided on the outer periphery of the central flow path 22 for supplying the carrier gas containing the sample component to the analysis unit. These flow paths 24 and 26 are flow paths for discharging the gas flowing in the gap between the sample tube 10 and the chamber 8 to the outside. Even if the O-ring 15 inside the connecting means 14 generates a gas that hinders analysis due to contact with the chamber 8, such a gas flows through the flow paths 24 and 26 together with a part of the carrier gas to the outside. Since it is discharged, the influence on the analysis by the heating temperature of the chamber 8 can be ignored.
Here, a pipe is added to the chamber 8 and connected to the carrier gas supply pipe 12 so that the carrier gas flows as a leak gas instead of diverting the sample gas, thereby suppressing the loss of the sample outside the system. Yes.

It is a schematic longitudinal cross-sectional view which shows one Example. It is a figure for demonstrating the operation | movement of the Example. In another Example, it is an expanded longitudinal cross-sectional view which showed the connection part of piping and a sample tube which send a sample to an analysis part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Heating part 4 Sample introduction piping 6 Sample tube insertion part 7 Drive mechanism 8 Chamber 10 Sample tube 12 Carrier gas piping 14 Connection mechanism 15 O-ring 16 Joint member 18 Joint support member 20 Stopper 22, 24, 26 Flow path

Claims (2)

A heating means for heating the sample tube having the measurement component adsorbed therein, a carrier gas supply means connected to one end of the sample tube for supplying a carrier gas into the sample tube, and connected to the other end of the sample tube And an introduction flow path for introducing the measurement component desorbed from the sample tube to the analysis unit,
In the sample tube heating type sample introduction device that heats the sample tube and desorbs the measurement component adsorbed inside, and leads the measurement component from the introduction flow path to the analysis unit by flowing the carrier gas by the carrier gas supply means,
The heating means includes a sample tube insertion portion that can be detachably inserted and housed in a state where one end of the sample tube protrudes, and the sample tube insertion portion does not include a seal member at the back of the sample tube insertion portion. The sample introduction device is connected to the introduction flow path, and
A sample tube comprising: a seal member that seals a gap between the sample tube inserted into the sample tube insertion portion and the heating means on the peripheral surface on the one end side of the sample tube outside the heating member. Heating type sample introduction device. The sample of the sample tube heating system according to claim 1, further comprising a carrier gas flow channel for flowing a carrier gas from the inner part of the sample tube insertion part through a gap between the sample tube and the heating means toward the seal member. Introduction device.

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