Thermal conductivity detector and gas chromatograph

Patent metadata

Field	Value
Publication number	US-10330651-B2
Application number	US-201514870208-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Oct 10, 2014
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A thermal conductivity detector that causes a fluid to come into contact with the surface of a heated temperature sensing element, that causes the temperature of the temperature sensing element to change according to the thermal conductivity of the fluid, and that detects the fluid based on a change in the electrical resistance of the temperature sensing element at that time or on a change in the value of a current to be applied to the temperature sensing element is provided. The thermal conductivity detector includes a cell space where the temperature sensing element is accommodated and to which a fluid is introduced and from which the fluid is discharged, a buffer space that is connected to a fluid outlet of the cell space, and a discharge channel that is connected to a fluid outlet of the buffer space.

First claim

What is claimed is:

1. A thermal conductivity detector comprising:
a cell member provided with a cell space including a fluid inlet and a fluid outlet, wherein the fluid inlet is provided at one end of the cell space and the fluid outlet is provided at another end of the cell space;
a temperature sensing element, accommodated inside the cell space, whose electrical resistance is changed according to thermal conductivity of a fluid flowing through the cell space;
a detection circuit for detecting a change in the electrical resistance of the temperature sensing element;
a buffer space connected to and downstream of the fluid outlet of the cell space and having a cross-sectional area that is greater than a cross-sectional area of the fluid outlet, wherein fluid that has flowed through the cell space flows in the buffer space; and
a discharge channel connected to a fluid outlet of the buffer space and having a cross-sectional area that is smaller than the cross-sectional area of the buffer space,
wherein the cell space is formed from a sample-side cell space and a reference-side cell space that are separated from each other, each of the sample-side cell space and the reference-side cell space including a fluid inlet and a fluid outlet,
wherein the temperature sensing element is formed from a temperature sensing element that is accommodated in the sample-side cell space and a temperature sensing element that is accommodated in the reference-side cell space, and
wherein the connection tube is formed from two connection tubes of a sample-side connection tube connecting the sample-side cell space and the buffer space and a reference-side connection tube connecting the reference-side cell space and the buffer space.

2. A thermal conductivity detector comprising:
a cell member provided with a cell space including a fluid inlet and a fluid outlet, wherein the fluid inlet is provided at one end of the cell space and the fluid outlet is provided at another end of the cell space;
a temperature sensing element, accommodated inside the cell space, whose electrical resistance is changed according to thermal conductivity of a fluid flowing through the cell space;
a detection circuit for detecting a change in the electrical resistance of the temperature sensing element;
a buffer space connected to and downstream of the fluid outlet of the cell space and having a cross-sectional area that is greater than a cross-sectional area of the fluid outlet, wherein fluid that has flowed through the cell space flows in the buffer space; and
a discharge channel connected to a fluid outlet of the buffer space and having a cross-sectional area that is smaller than the cross-sectional area of the buffer space,
wherein the cell space is formed from a sample-side cell space and a reference-side cell space that are separated from each other, each of the sample-side cell space and the reference-side cell space including a fluid inlet and a fluid outlet,
wherein the temperature sensing element is formed from a temperature sensing element that is accommodated in the sample-side cell space and a temperature sensing element that is accommodated in the reference-side cell space, and
wherein the connection tube is formed from a sample-side connection tube connected to the fluid outlet of the sample-side cell space and a reference-side connection tube connected to the fluid outlet of the reference-side cell space, the connection tubes being connected to the buffer space as one connection tube.

3. A gas chromatograph for supplying carrier gas to a column through a sample introduction section, and detecting, by a thermal conductivity detector, a gas component that has been separated by and that has flowed out from the column,
wherein the thermal conductivity detector comprises:
a cell member provided with a cell space including a fluid inlet and a fluid outlet, wherein the fluid inlet is provided at one end of the cell space and the fluid outlet is provided at another end of the cell space;
a temperature sensing element, accommodated inside the cell space, whose electrical resistance is changed according to thermal conductivity of a fluid flowing through the cell space;
a detection circuit for detecting a change in the electrical resistance of the temperature sensing element;
a buffer space connected to and downstream of the fluid outlet of the cell space and having a cross-sectional area that is greater than a cross-sectional area of the fluid outlet, wherein fluid that has flowed through the cell space flows in the buffer space; and
a discharge channel connected to a fluid outlet of the buffer space and having a cross-sectional area that is smaller than the cross-sectional area of the buffer space,
wherein the cell space is formed from a sample-side cell space and a reference-side cell space that are separated from each other, each of the sample-side cell space and the reference-side cell space including a fluid inlet and a fluid outlet,
wherein the temperature sensing element is formed from a temperature sensing element that is accommodated in the sample-side cell space and a temperature sensing element that is accommodated in the reference-side cell space, and
wherein the connection tube is formed from two connection tubes of a sample-side connection tube connecting the sample-side cell space and the buffer space and a reference-side connection tube connecting the reference-side cell space and the buffer space.

4. A gas chromatograph for supplying carrier gas to a column through a sample introduction section, and detecting, by a thermal conductivity detector, a gas component that has been separated by and that has flowed out from the column,
wherein the thermal conductivity detector comprises:
a cell member provided with a cell space including a fluid inlet and a fluid outlet, wherein the fluid inlet is provided at one end of the cell space and the fluid outlet is provided at another end of the cell space;
a temperature sensing element, accommodated inside the cell space, whose electrical resistance is changed according to thermal conductivity of a fluid flowing through the cell space;
a detection circuit for detecting a change in the electrical resistance of the temperature sensing element;
a buffer space connected to and downstream of the fluid outlet of the cell space and having a cross-sectional area that is greater than a cross-sectional area of the fluid outlet, wherein fluid that has flowed through the cell space flows in the buffer space; and
a discharge channel connected to a fluid outlet of the buffer space and having a cross-sectional area that is smaller than the cross-sectional area of the buffer space,
wherein the cell space is formed from a sample-side cell space and a reference-side cell space that are separated from each other, each of the sample-side cell space and the reference-side cell space including a fluid inlet and a fluid outlet,
wherein the temperature sensing element is formed from a temperature sensing element that is accommodated in the sample-side cell space and a temperature sensing element that is accommodated in the reference-side cell space, and
wherein the connection tube is formed from a sample-side connection tube connected to the fluid outlet of the sample-side cell space and a reference-side connection tube connected to the fluid outlet of the reference-side cell space, the connection tubes being connected to the buffer space as one connection tube.

Assignees

• Shimadzu Corp

Inventors

• Nakama Yuji
• Shibamoto Shigeaki
• Takahashi Kazunori
• Kashihara Minoru

Classifications

• G01N25/18 Primary

  by investigating thermal conductivity (by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18) · CPC title

• G01N30/66

  Thermal conductivity detectors · CPC title

• G01N30/62 Primary

  Detectors specially adapted therefor · CPC title