Waveguide direct-feed-type microwave plasma torch device

A microwave plasma and direct-feed technology, applied in the field of chemical measurement, can solve problems such as the limitation of coaxial cable bearing capacity, achieve the effect of improving microwave coupling efficiency and simplifying the complexity

Active Publication Date: 2013-08-28
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] MPT torches usually work with a variety of working gases (argon, helium, nitrogen, air, etc.) in the range of 10-500W, but at high power (>500W) coaxial cables are limited

Method used

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  • Waveguide direct-feed-type microwave plasma torch device
  • Waveguide direct-feed-type microwave plasma torch device
  • Waveguide direct-feed-type microwave plasma torch device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] see figure 1 , a waveguide direct-fed microwave plasma torch device, the device is mainly composed of a waveguide part, a tuning and auxiliary part, and a coaxial torch tube part.

[0049] see figure 2 , a schematic side-view profile of the main part of the waveguide direct-fed microwave plasma torch, where

[0050] The waveguide part includes a tapered waveguide 30 and a narrow-side compression waveguide 31, wherein the narrow-side compression waveguide 31 and the matched MPT three-tube coaxial torch 32 constitute the main part of the waveguide direct-fed MPT, and the narrow-side compression waveguide 31 is Microwaves are fed into the main body waveguide.

[0051] see image 3 , The coaxial torch 32 part includes the outer tube 14, the middle tube 11, the inner tube 10, the adjusting stud 13 and the coaxial centering washer 12, and the three tubes are in a coaxial structure. The inner diameter of the outer tube 14 is preferably 20-28 mm, the outer diameter of the...

Embodiment 2

[0069] see Figure 6 , Figure 7 , a simulation of electromagnetic field distribution in a waveguide-fed microwave plasma torch device. The simulation results are helpful to understand the working mechanism of this structure. The structure and dimensions of the device used are as described in Example 1.

[0070] Figure 6 This is the simulated diagram of the electromagnetic field distribution of the waveguide part in this example, and the simulated microwave frequency is 2450 MHz. The three sections of waveguides are BJ26, tapered waveguide 30 and narrow-side compressed waveguide 31 respectively. Microwaves are introduced from the left side of the BJ26 waveguide, transmitted to the short-circuit end on the right side of the narrow-side compression waveguide 31 and reflected back, thereby forming a standing wave field inside the waveguide. It can be seen from the figure that the electric field strength gradually becomes stronger from left to right, and is coupled into the ...

Embodiment 3

[0073] Figure 8 It is a diagram of the actual working state of the waveguide direct-fed MPT device designed based on the present invention. The structure and dimensions of the device used are as described in Example 1. The experimental conditions are as follows:

[0074] A magnetron is used as a microwave transmitting device, the output power is continuously adjustable from 100W to 1500W, and the device works at a power of 1000W. The carrier gas and maintenance gas fed into the middle tube 11 and the inner tube 10 are both argon with a purity of 99.999% and a gas flow >1.2 L / min. Oxygen shielding gas is introduced between the outer pipe 14 and the middle pipe 11 to shield the air in the environment, the purity is 99.999%, and the air flow is 1.5 L / min. The formed argon plasma flame 36 is as Figure 8 shown.

[0075] Figure 9 Schematic diagram of the structure of the argon plasma flame 36 formed by the waveguide direct-fed microwave plasma torch. The formed plasma con...

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Abstract

The invention provides a waveguide direct-feed-type microwave plasma torch device which comprises a waveguide portion, a tuning and auxiliary portion and a coaxial torch tube portion. The waveguide portion comprises a gradual-changing-type waveguide and a narrow-edge compression waveguide. The coaxial torch tube portion comprises an outer tube, a middle tube, an inner tube, a regulating stud and a coaxial centering washer. The tuning and auxiliary portion comprises a waveguide short-circuit sliding end, a torch tube reflection tuning end and a torch tube upper portion regulating end. The waveguide short-circuit sliding end comprises a waveguide short-circuit plate and a sliding rod. The torch tube reflection tuning end comprises the regulating stud and a reflection plate. The gradual-changing-type waveguide and the narrow-edge compression waveguide are directly fed into the metal coaxial torch tube, a formed plasma has a central channel so that a sample can be conveniently led into the plasma, and meanwhile bearing capacity for the sample is intensified. The device eliminates a coaxial cable, a coupling ring and the like, improves coupling efficiency, and expands the use power of the torch tube. The device can be used as an ionization source of an atomizer and an ionization source of an atom mass spectrum or used for decomposition and treatment of harmful chemicals and rubbish.

Description

technical field [0001] The invention belongs to the technical field of chemical measurement, and relates to a waveguide direct-feed microwave plasma torch device, which is a device for obtaining and maintaining plasma by using microwaves. It can be used as a light source for emission spectrum or other instrumental analysis (atomic fluorescence and Atomic mass spectrometry), the source of atoms or ions required, can also be used for the decomposition and treatment of harmful compounds. Background technique [0002] The microwave plasma torch (MPT) was invented by Professor Jin Qinhan in 1985, and the corresponding application patent number is CN 94205428.8. The torch is a coaxial structure of three metal tubes with one end open. The microwave energy enters the torch through the coaxial cable in the form of conductance / capacitance coupling. The length of the cavity is an odd multiple of 1 / 4 λ, and the microwave forms a standing wave in the cavity. , the plasma is formed at th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05H1/46
Inventor 金钦汉于丙文金伟周建光朱旦
Owner ZHEJIANG UNIV
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