What is the basic principle of four channel laser particle counter interpretation?

The four-channel laser particle counter is that the detection laser light from the optical sensor is scattered by the dust particles, and is received by the photosensitive element, and generates a pulse signal;

The pulse signal is output and amplified, then performed Digital signal processing, comparing with the standard particle signal, the comparison result is expressed with different parameters.

Particles in the air scatter under the irradiation of light. This phenomenon is called light scattering.

Light scattering is related to factors such as particle size, wavelength of light, particle refractive index and absorption characteristics particles of light.

With respect to scattered light intensity and particle size, there is a rule of thumb that the scattered light intensityby the particles increases with the increase in the surface of the particles.

Thus, as long as the intensity of the scattered light is measured, the size of the particle can be inferred. In fact, the intensity of the scattered light produced by each particle is very small, which corresponds to a very small light pulse;

It is necessary to use the amplification of the converter photoelectric to convert the pulse light into an electric pulse with a large signal amplitude, and then further amplifies and filters the electronic circuit to complete the counting of a large number of electric pulses.

At this time, the number of electric pulses corresponds to the number of particles, and the amplitude of the electric pulses corresponds to the size of the particles. This is the basic principle of the light scattering laser dust particle counter.

Introduction to the circuit system of thefour channel laser particle counter

After the particles of different particle sizes are converted by the laser dust particle counter\'s photoelectric system, they will produce electric pulse signals of different amplitudes (voltages), the larger the particle size, the higher the pulse voltage.

The relationship between signal voltage and particle size is also called conversion sensitivity. For a given four-channel laser particle counter, there is a one-to-one correspondence between particle size and pulse voltage.

For example, the conversion sensitivity of a four-channel laser particle counter is 0.3μm corresponds to 69mv, 0.5μm corresponds to 531mv, 1, 0 μm corresponds to 701 mv, etc. ;

If the laser dust particle counter detects a 100 mv pulse, the particle size should bere greater than 0.3 μm but less than 0.5 μm.

The laser dust particle counter is an instrument that measures the number of particles greater than or equal to a certain particle size, and its internal circuit is a circuit that counts the number of pulses greater than or equal to a certain voltage value.

For the example of the previous paragraph, to measure the number of particles greater than or equal to 0.3μm in the air, in the circuit it is necessary to count the number of pulses greater than or equal to at 69mv;

To measure the number of particles greater than or equal to 0.5μm, in the circuit is to count the number of pulses greater than or equal to 531mv, and so on.

Thus, the measurement of dust particles with instruments mainly depends on the conversion sensitivity setting.

Additionally, it should be noted that the conversion sensitivity of each laser particle counter tofour channels is different and should be calibrated with standard particles regularly after leaving the factory to obtain the best conversion sensitivity value.

The system circuit is the circuit that completes the amplification, discrimination and counting of the pulse signal. In addition, it also includes power supply, control, display, calculation, printing and other circuits.

Label: Particle Counter