The laser dust particle counter is core device for accurately detecting the concentration of suspended particles in the environment. It consists of four core modules working together: the optical system, the sampling system, the detection and signal processing system, and the display and data output system.
The optical system, as the core sensing unit, includes core components such as semiconductor laser, scattering chamber, and photomultiplier tube or photodiode, along with auxiliary components such as lens groups, light traps, and baffles. The laser light source emits stable monochromatic light, which is focused by the lens group into the scattering chamber. The light trap absorbs the unscattered direct light to avoid interference, and the photodetector specifically captures the particle scattering light signal.
The sampling system is responsible for air collection and transport. Its core components include a sampling pump, flow controller, sampling port, sampling pipeline, and filter. During operation, the sampling pump actively draws in the air to be tested, and the flow controller strictly controls the flow rate to common standard specifications such as 2.83 L/min and 28.3 L/min to ensure sampling accuracy; the filter removes impurities from the pipeline to prevent contamination of the scattering chamber and affecting the detection results.
The detection and signal processing system is crucial for counting and analysis, consisting of a signal amplifier, pulse amplitude discriminator, counter, and microprocessor. The photodetector converts the scattered light signal into an electrical pulse signal, which is amplified. The discriminator distinguishes particles of different sizes based on the pulse amplitude, the counter counts the corresponding number, and the microprocessor calculates and analyzes the data, extracting core information such as particle concentration and size distribution.
The display and data output system is responsible for information presentation and transmission. Its core components include a display screen, buttons, RS232, USB, Ethernet and other data interfaces, and a printer interface. The display screen shows real-time data such as particle concentration, size distribution, and sampling time. Various interfaces support data export and storage or direct printing of reports to meet archiving needs.
The device works based on the light scattering method. The core logic is that under the same conditions, the intensity of scattered light from particles is positively correlated with the particle size; the working process is divided into five stages. In the sampling stage, air passes through the scattering chamber at a constant speed, and suspended particles enter the laser irradiation area; in the scattering stage, the laser irradiates the particles to produce scattered light, the intensity of which is affected by particle size, shape, and refractive index, with larger particles producing higher intensity. During the signal conversion stage, the photoelectric detector captures scattered light and converts it into electrical pulses. The pulse amplitude is proportional to the scattered light intensity and particle size. In the processing and counting stage, the amplified pulses are classified according to preset thresholds such as 0.3μm, 0.5μm, and 5μm. The counter then tallies the number of particles in each range and converts this into particle concentration (units of particles/m³ or particles/ft³). In the output stage, the microprocessor processes the results, displays them on the screen, and outputs them to external devices via an interface for storage or report generation.
Dust particle counters are widely used in various clean environments, including the medical device and pharmaceutical industries, electronics industry, research and laboratory sectors, and food industry.
Suzhou Pharma Machinery Co.,Ltd.
2026/05/27
Tia
