A Low Pressure Hydrogen Flame Ionization Detector

Abstract

The invention relates to a low-pressure hydrogen flame ionization detector which comprises a lower shell, a gas inlet pipe, an upper shell and a sealing barrel, wherein the lower shell comprises a disk base with a large diameter and a cylindrical base with a small diameter; a slot body is formed in each of the top of the cylindrical base and the bottom of the disk base; a through hole is formed between the two slot bodies; an air channel communicated with the through hole is formed in the bottom surface of the disk base; the upper end of the air inlet pipe is coaxially connected with a nozzle through a clamping sleeve and is connected into the slot body in the bottom of the disk base in a fastening manner; the nozzle passes through the through hole and is positioned in the slot body in the top of the cylindrical base; a gap is reserved between the nozzle and the inner wall of the through hole and is communicated with the air channel; an opening for feeding hydrogen is formed in one side of the gas inlet pipe; the upper shell is of a barrel-shaped structure; the lower end of the upper shell is connected to the top of the cylindrical base; an insulating sleeve is arranged in the upper shell; a collector is in tight fit in the insulation sleeve; the top of the upper shell is coaxially connected with a gas outlet pipe in a fastening manner; the opening end of the sealing barrel is connected with the disk base in a fastening sealing manner; the sealing barrel encircles the cylindrical base and the upper shell.

Description

technical field [0001] The invention relates to a hydrogen flame ionization detector, in particular to a low-pressure hydrogen flame ionization detector. Background technique [0002] The hydrogen flame ionization detector (flameionization detector, FID) was proposed by scholars in Australia and South Africa in 1958. Its working principle is to use the flame generated by the combustion of hydrogen and air as the energy source, hydrogen and the gas to be measured carried by the carrier gas Entering the detector from the nozzle, the supporting gas (air) is introduced from the surroundings, and the gas to be tested undergoes chemical ionization in the flame, and the ionization produces ions several orders of magnitude higher than the base flow. Under the directional action of the high-voltage electric field, an ion flow is formed, weak The ion current (10 -12 ~10 -8 A) After high resistance (10 6 ~10 11 Ω) amplification to obtain a measurable electrical signal. The obtaine...

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Problems solved by technology

The current popular hydrogen flame ionization detectors on the market also have certain shortcomings. When the air is fed into the combustion, because the diameter of the hole is too large, the flame is unstable due to the instantaneous air entering, and a large signal flickering noise will be generated at the same time. Seriously affect the effect and stability of the detection; often the temperature of the flame and the relative position of the collector and the nozzle will also affect the sensitivity of the detector

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