JP2002310971A - Heat conductivity detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat conductivity detector capable of raising the temperature of a hot wire while enhancing sensitivity without increasing noise and delaying a response speed. SOLUTION: The heat conductivity detector has the first and second flow channels provided on a base block, and the hot wires respectively provided at the first and second flow channels and constituted so as to allow carrier gas and measuring gas to flow to either one of the first and second flow channels while allowing reference gas to flow to the other flow channel. Further, the detector is provided with an expanded part for keeping away the cross-sectional inner walls in the cross-sectional shapes of the first and second flow channels from the hot wires, and rectifying parts for rectifying a measuring fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal conductivity detector used for a gas chromatograph.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of the structure of a conventional example generally used in the prior art, FIG. 5 is a plan view of FIG. 4, and FIG.
7 is a sectional view taken along line X-X or Y-Y of FIG. 7, FIG. 7 is a sectional view of a main part of Z-Z of FIG. 6, and FIG. 4 to 7, reference numerals 2 and 3 denote first and second flow paths provided in the base block 1.

[0003] Reference numeral 4 denotes a heating wire provided in each of the first and second flow paths 2 and 3. In this case, a total of four are used. As shown in FIG. 7, the first and second flow paths 2 and 3 have a circular cross section centered on the heating wire 4.

[0004] 5 is a first flow path 2 or a second flow path 3
Gas inlet pipe connected to the 6 is a gas outlet pipe connected to the first flow path 2 or the second flow path 3. Reference numeral 7 denotes a lead having one end connected to the heating wire 4.

In the above configuration, as shown in FIG. 8, carrier gas + measurement gas A flows through one of the first and second flow paths 2 and 3, and comparison gas B flows through the other flow path. C
Is the power supply and D is the measurement output.

[0006]

However, such an apparatus has the following problems. Since the inner wall of the base block 1 absorbs the heat generated by the heating wire 4,
Is disposed close to the inner wall of the base block 1 (the walls of the flow paths 2 and 3), the temperature of the heating wire 4 is lowered, and the sensitivity is lowered.

Therefore, when the inner wall diameter of the base block 1 is increased, the temperature of the heating wire 4 can be increased, and the sensitivity can be improved.

On the other hand, when the inner wall diameter of the base block 1 is increased, the following problems occur. (1) Noise increases due to an increase in turbulence in the flow of the measurement fluid. (2) Since it takes time to replace the gas, the response speed is reduced.

[0009] An object of the present invention is to solve the above-mentioned problems, and it is possible to increase the hot-wire temperature without increasing noise and without decreasing the response speed, and to improve sensitivity. An object of the present invention is to provide a thermal conductivity detector that can be used.

[0010]

According to the present invention, there is provided a thermal conductivity detector according to the present invention, wherein the first and second flow paths provided in a base block are provided. A heat wire provided in each of the first and second flow paths, and a heat flow in which the carrier gas flows through one of the first and second flow paths and the comparison gas flows through the other flow path of the measurement gas. The conductivity detector is characterized in that in the cross-sectional shape of the first and second flow paths, there is provided an enlarged portion for keeping the inner wall of the cross section away from the hot wire and a rectifying portion for rectifying the measurement fluid.

According to a second aspect of the present invention, in the thermal conductivity detector according to the first aspect, a plurality of the enlarged portions and the rectification portions are provided alternately around the heat ray. I do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention. In the figure, the configuration of the same symbol as in FIG. 6 represents the same function. Hereinafter, only differences from FIG. 6 will be described.

In the figure, first and second flow paths 11 and 12 are shown.
Is an enlarged portion 1 that keeps the inner wall of the section away from the hot wire 4
Rectifiers 112 and 12 for rectifying the measurement fluid
And 2. In this case, four enlargement parts and four rectification parts are provided for one flow path.

As a result, (1) the enlarged portions 111 and 1 that keep the inner wall of the section away from the hot wire 4
21 and a rectifying unit 11 for rectifying turbulence in the flow path of the measurement fluid FL
2 and 122, the heat conductivity temperature can be increased without increasing noise and the response speed is not reduced, and a thermal conductivity detector capable of improving sensitivity is obtained. Can be

Specifically, for example, as an example, 1.5 times the sensitivity was obtained in the voltage application method to the heating wire 4 and 1.8 times the sensitivity in the current application method.

(2) The enlarged portion 111 with the hot wire 4 as the center
Since a plurality of the rectifiers 121 and the rectifiers 112 and 122 are provided alternately, the flow of the measurement fluid FL becomes regular, and a thermal conductivity detector with improved noise resistance can be obtained.

FIG. 2 is an explanatory view of a main part configuration of another embodiment of the present invention. In this embodiment, the first and second flow paths 2
The cross-sectional shapes of the cross-sections 1 and 22 include enlarged portions 211 and 221 for moving the inner wall of the cross-section away from the heat rays, and rectification portions 212 and 222 for rectifying turbulence in the flow path of the measurement fluid FL. In this case, two expansion parts and two rectification parts are provided for one flow path.

As a result, the cross-sectional shapes of the flow paths 21 and 22 can be made simple, and an inexpensive thermal conductivity detector can be obtained.

FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention. In this embodiment, the first and second flow paths 3
The cross-sectional shapes of the cross-sections 1 and 32 include enlarged portions 311 and 321 that keep the inner wall of the cross-section away from the hot wire and rectification portions 312 and 322 that rectify turbulence in the flow path of the measurement fluid FL. in this case,
A large number of enlarging portions and rectifying portions are provided for one flow path.

As a result, it is possible to increase the area of the enlarged portions 311 and 321 and obtain a thermal conductivity detector capable of further improving the sensitivity.

It is to be noted that the foregoing description has been directed to specific preferred embodiments for the purpose of illustration and illustration of the invention. Therefore, the present invention is not limited to the above-described embodiment, but includes many more changes and modifications without departing from the spirit thereof.

[0022]

As described above, according to the first aspect of the present invention,
According to the above, the following effects are obtained. A thermal conductivity detector that can increase the hot-wire temperature without increasing the noise and without reducing the response speed, and that can improve the sensitivity can be obtained.

According to the second aspect of the present invention, the following effects can be obtained. Since a plurality of enlarged portions and rectification portions are alternately provided around the heat ray, the flow of the measurement fluid becomes regular, and a thermal conductivity detector with improved noise resistance can be obtained.

Therefore, according to the present invention, there is provided a thermal conductivity detector capable of increasing the hot-wire temperature without increasing noise and reducing the response speed and improving sensitivity. Can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a configuration of a main part of a conventional example generally used in the related art.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a sectional view taken along line XX or YY of FIG. 4;

FIG. 7 is a cross-sectional view of a ZZ main part of FIG. 6;

FIG. 8 is an operation explanatory diagram of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base block 2 1st flow path 3 2nd flow path 4 Heat wire 5 Gas inlet pipe 6 Gas outlet pipe 7 Lead 11 1st flow path 111 Enlarged part 112 Rectification part 12 Second flow path 121 Enlarged part 122 Rectification Part 21 first flow path 211 enlarged part 212 rectification part 22 second flow path 221 enlarged part 222 rectification part 31 first flow path 311 enlarged part 312 rectification part 32 second flow path 321 enlarged part 322 rectification part A Carrier gas + Measurement gas B Comparative gas C Power supply D Measurement output FL Measurement fluid

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G040 AB09 EA02 ZA03 2G060 AA01 AE19 AF07 AG01 BA05 BB05 BC04

Claims (2)

[Claims] 1. A first and a second flow path provided in a base block; a heat wire provided in each of the first and the second flow paths; and a heat wire provided in the first and the second flow paths. In a thermal conductivity detector in which a carrier gas and a measurement gas flow in one of the flow paths and a comparison gas flows in the other flow path, the cross-sectional inner walls of the first and second flow paths are expanded away from the hot wire. A thermal conductivity detector, comprising: a rectifying section for rectifying a measurement fluid. 2. The thermal conductivity detector according to claim 1, wherein a plurality of the enlarged portions and the rectification portions are provided alternately around the heat wire.