Solid thermal conductivity detector for cylindrical thermal sensitive region

A thermal conductivity detector, columnar technology, applied in the field of solid-state thermal conductivity detector, can solve problems such as unusable, large output signal, noise, etc., achieve excellent repeatability of response value, expand application range, and large surface area

Active Publication Date: 2010-06-23
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This bow-type thermal wire will undergo elastic vibration when there is a slight vibration in the outside world, resulting in a large noise in the output signal
Therefore it cannot be used during exercise
In addition, this type of thermal conductivity detector has a minimum cell volume of 20 microliters, which is not suitable for use with capillary columns.

Method used

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  • Solid thermal conductivity detector for cylindrical thermal sensitive region
  • Solid thermal conductivity detector for cylindrical thermal sensitive region
  • Solid thermal conductivity detector for cylindrical thermal sensitive region

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A solid-state thermal conductivity detector, on a ceramic rod 101 with a diameter of 0.6mm, a rhenium-tungsten alloy wire with a diameter of 15μm is used to wind a 100 ohm / 0°C thermistor 102, and the lead wire 103 is welded to the lead wire 104, and then the The surface is coated with a low-temperature ceramic protective layer 105 with a thickness of 2 microns. This component is referred to as thermal element 100 . The two fabricated thermosensitive elements 100 are respectively embedded in two flow cells 201 to form a detection cell, which has a gas inlet 202 and a gas outlet 203 respectively. The distance between the thermal wire 102 and the wall of the detection cell is 100-200 microns. This pair of heat-sensitive elements is connected with an external circuit to form a Wheatstone bridge.

[0037] Use two elastic quartz capillary columns with a length of 20 meters and an internal diameter of 0.53mm to be connected to the two inlets of the detector respectively, one...

Embodiment 2

[0039] Solid-state thermal conductivity detector, on a glass tube with an outer diameter of 1mm (as a support 101), a thermal electrode 102 with a resistance of 22 ohms / 0°C is wound with a platinum wire with a diameter of 20 μm, and the platinum wire lead 103 is welded to a fixed lead wire 104 , coating glass glaze with a thickness of about 1 μm on the surface of the heat-sensitive area to form a protective film 105 . The two fabricated thermosensitive elements are respectively embedded in the two flow cells 201 to form two independent detection cells. The distance between the surface of the heat-sensitive area and the wall of the detection pool is 200-300 microns. The inlet 202 of the detection cell is connected to the outlet of the chromatographic column, and the outlet 203 of the detection cell is emptied. This pair of heat-sensitive elements is connected with an external circuit to form a Wheatstone bridge.

[0040] Use two micro-packed stainless steel columns with a len...

Embodiment 3

[0042] On a quartz tube with an outer diameter of 0.8mm (as a support 101), a thermal electrode 102 with a resistance of 100 ohms / 0°C is wound with a platinum wire with a diameter of 10 μm, and the platinum wire lead 103 is welded to a fixed lead electrode 104. The surface is coated with 0.5 μm polyimide to form the protective layer 105 . The two fabricated thermosensitive elements are respectively embedded in the two flow cells 201 to form two independent detection cells. The distance between the surface of the thermistor wire and the wall of the detection cell is 50-180 microns, the inlet 202 of the detection cell is connected to the outlet of the chromatographic column, and the outlet 203 of the detection cell is emptied. This pair of heat-sensitive elements is connected with an external circuit to form a Wheatstone bridge.

[0043] Use two elastic quartz capillary columns with a length of 30 meters and an internal diameter of 0.53mm to be connected to the two inlets of th...

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Abstract

The invention relates to a solid thermal conductivity detector for a cylindrical thermal sensitive region, which is a gas thermal conductivity sensor for the detection of gas chromatography and change of the gas composition. The solid thermal conductivity detector comprises a cylindrical thermal element and a flow cell body. The cylindrical thermal element comprises a cylindrical support body the surface of which is fixed with a thermal sensitive electrode. Both ends of a metal wire or a thermal sensitive coating film are respectively connected with extraction electrodes fixed at the same end of the cylindrical support body. The inner cavity of the flow cell body takes a shape of cylinder. The space formed from the cylindrical thermal element and the inner cavity of the flow cell body serves as a detection cell. The cylindrical thermal element is embedded in the flow cell body. The axis of the cylindrical support body is coaxial to that of the detection cell. Both ends of the flow cell body are respectively provided with a gas inlet and a gas outlet. The gas inlet is arranged on the axis of the detection cell. The extraction electrodes are electrically connected with an external circuit by extraction wires. The temperature resisting stability of the detector of the invention is different according to the use different thermo-sensitive materials. When the metal wire is used, the temperature can reach 400 DEG C so as to not only improve the temperature resistance of the device, but also simplify the manufacturing process and requirements and widen the application field.

Description

technical field [0001] The invention relates to a solid-state thermal conductivity detector, which is a gas thermal conductivity sensor, which is used for gas chromatography and gas composition change detection, and is widely used in industrial online instruments and laboratory analysis instruments. Background technique [0002] The miniaturization of analytical instruments is the mainstream of the development of analytical instruments in the 21st century. Miniaturization not only reduces the volume and weight of the instrument, but also reduces the power consumption and material consumption of the instrument. The key to the miniaturization of the instrument is the miniaturization of the detector or sensor, which reduces the volume and power consumption of the detection cell by more than 90%, and then can use a smaller separation column and power supply, which greatly reduces the energy consumption and carrier gas consumption. reduce. [0003] Solid State Thermal Conductivi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/66G01N25/20
Inventor 关亚风朱蕴卿夏金伟王建伟
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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