How to count the number of dust particles? -Huaqiang Electronic Network

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

GW MB10F 0.8A 1000V rectifier bridge

Factory direct 0805 red light quality absolutely guaranteed price absolute advantage

one,

Dust particles

counter

Principle--Introduction

Dust particles

counter

The English name is Thedustparticlecounter, an instrument used to detect the number and distribution of dust particles per unit volume in a clean environment. It has the characteristics of fast detection speed, high precision and small human influence. It has been widely used in drug testing institutes, epidemic prevention stations, blood centers, pharmaceutical workshops, precision instrument processing and quality supervision.

two,

Dust particle counter principle

--classification

Dust particle counters have different classification methods according to different classification standards. They can be divided into small flow counters and large flow counters according to different flow sizes; they can be divided into handheld counters and desktop counters according to different volumes and shapes; The principle can be divided into light scattering method test counter, weighing method test counter, inertia test counter, microscope test counter, etc.; according to the number of test channels can be divided into single channel counter, dual channel counter and multi-channel counter .

three,

Dust particle counter principle

--structure

The dust particle counter is mainly composed of a light source, two sets of lenses, a measuring cavity, a photodetector and an amplifying circuit. Among them, the light source greatly affects the performance of the counter, and is one of its key components. It needs to meet the characteristics of long life, high stability, and low external interference; two sets of lenses are used to complete the focusing function, and one set is used to focus the light source. The emitted light, a set of scattered light for focusing the scattering phenomenon; the measuring chamber is used to scatter the particles in the air under illumination; the photodetector is used to convert the optical pulse signal into an electrical pulse signal; the amplifying circuit is used to A weak electrical signal is amplified and a pulse signal that satisfies the requirements is selected.

four,

Dust particle counter principle

First, the light from the light source is focused in the measuring chamber through the lens group 1, as shown in the above figure. Secondly, the air passes through the measuring chamber, and the particles in the air are scattered in the measuring chamber due to the illumination, and the surface area of ​​the particles is larger. The stronger the intensity of the scattered light is generated, the size of the particles can be known by measuring the intensity of the scattered light; again, the generated scattered light is substantially a weak pulse signal, which is sent through the lens group 2 The photodetector is converted into an electrical pulse signal; finally, the electrical pulse signal is processed by amplification, selection, etc. of the amplifying circuit, and the desired signal is selected, counted and displayed, and thus the dust particle counter is completed. The function.