Optical equivalent particle size spectrometer with internal circulation sheath flow structure

Abstract

The invention discloses an optical equivalent particle size spectrometer with an internal circulation sheath flow structure. The optical equivalent particle size spectrometer comprises a gas path module, a light path module and an analog-to-digital conversion module. The gas path module comprises a sample injection gas pipe, a sample outlet gas pipe and a sheath flow pipe. The sheath flow pipe sleeves the peripheral surface of the sample injection gas pipe and is coaxial with the sample injection gas pipe, and an annular hole for sheath gas to pass through is formed between the sheath flow pipe and the sample injection gas pipe. The light path module comprises a light source, an ellipsoidal reflector, a lens group and a photoelectric converter. An emitting light path of the light source ispositioned on an axial vertical plane of the sample injection gas pipe. The long axis of the ellipsoidal reflector is perpendicular to the light source emitting light path, the front focus of the ellipsoidal reflector is located at the axial intersection of the light source emitting light path and the air inlet pipe, the front focus of the lens set coincides with the rear focus of the ellipsoidalreflector, and the photosensitive area of the photoelectric converter is located at the rear focus of the lens set. The particle counter provided by the invention can accurately and quickly measure the particle size of the particles in the gas to be detected and the particle concentration distribution of each particle size.

Description

technical field [0001] The invention relates to the technical field of aerosol detection, in particular to an optical equivalent particle size spectrometer with an inner circulation sheath flow structure. Background technique [0002] In recent years, my country's atmospheric particle monitoring technology has made great progress; in the existing technology, the particle size spectrometer is mainly composed of an illumination system, a scattered light collection system, a photoelectric converter, and a gas path system. The axes of the system and the gas path system intersect at the light-sensitive central point. When working, the gas path system sucks the measured air into the light-sensitive area of ​​the particle counter, where the dust particles generate a scattering signal proportional to the particle size under the light beam irradiation; scattering The light signal is incident on the photoelectric converter after being received by the scattered light collection system....

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Problems solved by technology

[0003] However, there are many problems in the prior art. First, the optical path structure mostly uses a spherical mirror to collect scattered light into the photodiode. Due to the influence of stray light, the signal-to-noise ratio is low; secondly, the measured gas is easy to diffuse and gather, which affects the measurement accuracy; finally Particle counting is inefficient and cannot quickly reflect the actual concentration; therefore, a method that can solve such problems needs to be found

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