Selection of the dust particle counter flow size

The selection of dust particle counter flow size The flow rate of dust particle counters on the market now has: 2.
83L/min, 28.
3L/min, 50L/min, 100L/min, the size of these flows, in fact, is the size of the sampling rate, from the digital size is very intuitive, the role of the dust particle counter flow is to directly affect the sampling rate, and then directly affect the detection power
.
The higher the flow rate, the more air data collected per minute, the more it can represent the true cleanliness level of
the cleanroom.
Foreign countries use "cubic feet", which is converted into domestic "liters", 1 cubic foot = 28.
3168 liters
.
The particle counter was originally produced according to foreign norms, which produced 0.
1 cubic feet per liter, or 2.
83 liters per minute
.
Therefore, it is generally recommended to use a particle counter with a flow rate of more than 28.
3L/min, which can improve the detection power and then improve the working power
.
Particles in the air disperse under the illumination of light, a phenomenon known as light scattering
.
Light scattering is related
to particle size, wavelength of light, refractive index of particles, and light absorption characteristics of particles.
However, in terms of scattered light intensity and particle size of air particles, there is a fundamental law, and the scattered light intensity of particulate matter increases with the increase of the surface area of particulate matter
.
Just by measuring the intensity of the scattered light, you can infer the magnitude
of the particles.
This is the fundamental principle
of how the light-scattered particle counter works.
In fact, the scattered light generated by each particle is very weak, a very small pulse of
light.
The demand is expanded by the photoelectric converter, the light pulse is converted into an electrical pulse with a large fluctuation of the signal, and then further expanded and screened by the electronic circuit, and then the counting
of many electrical pulses is completed.
At this point, the number of electrical pulses corresponds to the number of particles, and the fluctuations of the electrical pulses correspond to the size of the
particles.
Detailed operation principle of the dust particle counter: the light from the light source is focused in the measuring chamber by the lens group 1, when each particle in the air passes through the measuring chamber rapidly, the incident light will be scattered once to form a light pulse signal
.
This optical signal is sent to the light detector through the lens group 2, converted proportionally into an electrical pulse signal, and then through the expansion and screening of the electronic circuit of the instrument, the signal of demand is detected, and displayed by the counting system
.
Lumei Xinchuang (Suzhou) Biotechnology Co.
, Ltd.
is a collection of scientific research, development, production, sales, service in one of the innovative enterprises, products are plankton bacteria sampler, microbial limit meter, bacteria instrument, dust particle counter, air cover and other products, the company is committed to providing overall solutions
for China's microbiology laboratory.