Concentration measuring device and method for dust in large diameter range

Abstract

The invention discloses a concentration measuring device and method for dust in large diameter range. Aiming at the shortcoming that scattering integration method in the prior art is not applicable when the particle size is smaller than 10 microns, the measuring device uses a multistep neutral density filter to attenuate transmission light and scattered light to a same light intensity level, realizes simultaneous shooting of transmission light and scattered light in a measurement system of a single digital area-array camera, and has the advantages of high sensitivity, fast response and simple and compact optical system. According to the obtained information of scattered light and transmission light, the distribution of particle size can be acquired; with the known particle size distribution, a method combined scattered light with scattering integration can be used to measure dust concentration of micron level, and a method combined transmission light with light extinction can be used to realize the measurement of dust concentration of submicron and nanometer levels. The invention successfully realizes the measurement of dust concentration of micron, submicron and nanometer levels, covers large particle size range, and has great market advantage.

Description

technical field [0001] The invention relates to a dust concentration measuring device and method, in particular to a dust concentration measuring device and method in a large particle size range, which realizes simultaneous measurement of transmitted light and forward small-angle scattered light in one measuring device. Wide, covering nano-scale and micron-scale dust particles. Background technique [0002] One of the main hazards of dust is air pollution, and the second is explosion hazards. In some occasions, dust can also affect production. For example, dust will reduce the power generation efficiency of solar panels, resulting in hundreds of millions of yuan in indirect losses every year for solar photovoltaic power generation projects in my country. Therefore, dust concentration measurement is of great significance in energy research, environmental protection, atmospheric science and other fields. At present, a variety of dust concentration measurement technologies have...

AI Technical Summary

Problems solved by technology

The advantage of the scattering integration method is that the particle concentration can be calculated without predicting the particle size, but the scattering integration method measures the particle concentration based on the Fraunhofer diffraction theory. The light intensity distribution cannot be accurately represented in the interior, so the scattering integration method is no longer applicable when the particle size is less than 10 μm

The extinction method is simpler than other optical methods in terms of optical principles and optical measurement devices. The lower limit of the particle size range can reach several nanometers, and the upper limit can reach the micron level, but the disadvantages are also obvious. It is necessary to know the average particle size However, the light total scattering method at a single wavelength cannot solve two unknowns at the same time: the average particle size and the number of particles, and the concentration measurement has a large dependence on the average particle size, so the error of the average particle size can lead to a large concentration measurement error

[0004] In addition, in the existing dust concentration measurement system, due to the large difference between the transmitted light intensity and the scattered light intensity of the particles, it is difficult to make reasonable exposure and collection at the same time within the dynamic detection range of the photodetector, so the optical measurement device needs multiple The detector measures the separated scattered and transmitted light, so the system is more complex

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