2. Working principle of particle counter
Particle counters use the light scattering method.
It sucks ambient air from the inlet nozzle and emits laser light to the area.
Then, emitted light scatters when it interacts with particles.
A photodiode in the particle counter detects the scattered light and converts into an electrical signal.
Particle size is determined based on the strength of the voltage signal and number of particles is calculated by number of waveforms.
3. Difference between particle counters and dust monitors
Main difference between particle counters and dust monitors is the unit of measurement.
Particle counters measure "number of particles in the air (pcs/m3)" and dust monitors measure "particle concentration in the air (mg/m3)".
In case of low dust concentration situation, it is better to use particle counters (pcs/m3) because it's resolution is high and dust concentration value (mg/m3) is too low to use dust monitors.
But on the other hand, particle counter value (pcs/m3) becomes too high and difficult to make judgement in case of high dust concentration.
In this case, it is better convenient to use dust monitors (mg/m3).
Easier way to make judgement whether particle counters or dust monitors should be used is whether the dust concentration to be measured is higher or lower than the concentration level of general office or suburban outdoor.
Dust monitors are better in case it's higher than it.
Particle counters are better if it's lower than it.
In addition, particle counters are single measurement method.
Dust monitors are continuous method generally equipped with analog signal (DC4-20mA) for the continuous measurement output and have a few types to suit for each application.
Please refer to the positioning map below for more details.
Positioning map