Working principle of handheld particle counter
A handheld particle counter is an instrument that counts dust particles using the principle of light scattering. Light scattering is related to factors such as particle size, light wavelength, particle refractive index, and the particle's absorption characteristics. However, regarding the intensity of scattered light and particle size, there is a fundamental rule: the intensity of scattered light increases with the particle's surface area. Thus, when a certain flow rate of dust-laden gas is passed through a beam of strong light, the particles emit scattered light. This scattered light is projected through a focusing lens onto a photomultiplier tube, converting the light pulses into electrical pulses. The number of particles is determined from the number of pulses. The particle diameter is then calculated based on the functional relationship between the intensity of the scattered light and the particle size. Therefore, by measuring the intensity of the scattered light, the size of the particles can be deduced; this is the basic principle of a light scattering particle counter.
The AIRY Model P611 handheld particle counter, offered by Shenzhen Gongcai.com, is a portable, high-precision airborne particle counter. This calculator features a user-friendly design and simple setup. Its compact structure and lightweight design, along with six built-in counting channels, allow for simultaneous detection and measurement of six different particle sizes. Furthermore, the Airy P611 incorporates the latest long-life laser diode technology and a high-efficiency suction pump, achieving a maximum detection capacity of 4,000,000 particles per cubic foot, making it the most accurate and reliable on the market. The standard multi-functional, large-size color LCD screen clearly displays detection results and various information. The built-in data storage module and USB port allow for automatic/manual storage of up to 10,000 data sets. With dedicated data analysis software, data can be easily exported to a computer for analysis and storage.
The AIRY Model P611 handheld particle counter from the USA is an instrument used to measure the number and size distribution of dust particles per unit volume in clean environments, thus providing a basis for assessing air cleanliness. Therefore, it is widely used in industries such as medical, cleanrooms, and laminar flow hoods.
Application Area Analysis:
Applications in the medical field: Given the nature of drug preparation work in cleanrooms and the potential adverse consequences of uncontrolled environments, the U.S. Food and Drug Administration (FDA) has established stringent requirements for temperature, humidity, air change rate, and the number of airborne particles. The FDA uses the ISO 14644-1 standard, which specifies the maximum particle concentration per square meter in cleanrooms. ISO 14644-1 provides a strict classification of particles ranging from 0.1 μm (smaller than bacteria) to 5 micrometers (floral fragments and mold spores) and is used as a common reference by regulatory agencies worldwide.
Air cleanliness standards for cleanrooms (areas) in Chinese pharmaceutical manufacturing
Pharmaceutical ingredients and certain manufacturing applications require continuous monitoring of particulate matter counts. Particle counters and indoor air quality monitors can detect and measure pollutants such as dust, mold spores, debris, volatile organic compounds (VOCs), and even airborne bacteria in specific environments, and provide feedback on the monitored data through a building management system (BMS).
Applications in the Cleanroom Field: The term and concept of cleanroom originated in European medicine in the 1760s. At that time, it was understood only as a sterilized work environment such as treatment rooms and operating rooms where infection rates could be controlled after spray disinfection. With the development of cleanroom technology, to ensure that cleanrooms and related environments meet controlled standards, international standards have been established. Cleanroom classification standards, like the international standard ISO 14644, classify the air cleanliness level of cleanrooms (areas) and related controlled environments based solely on the concentration of suspended particles, considering only particle groups with a cumulative distribution within the particle size limit (lower limit) range of 0.1µm to 5.0µm. Based on particle size, they can be classified into conventional particles (0.1µm to 5.0µm), ultrafine particles (<0.1µm), and macroparticles (>5.0µm).
ISO/DIS 14644-1 Classification of Cleanrooms and Clean Areas by Concentration of Airborne Particulates
Airborne particulate cleanliness level in cleanrooms and clean areas
Applications of Clean Benches: It is well known that the lifespan of a clean bench is related to the cleanliness of the air. In temperate regions, clean benches can be used in general laboratories. However, in tropical or subtropical regions, where the atmosphere contains high levels of pollen or dust, clean benches should be placed in a well-ventilated room with double doors. Under no circumstances should the air inlet hood of the clean bench face open doors or windows, as this can affect the lifespan of the filters. Therefore, particle counters are needed to monitor the cleanliness of the clean bench and to detect leaks in the HEPA filters, preventing leaks from affecting the entire production process. The main purpose is to detect whether suspended particles at various points exceed the cleanliness requirements of the clean area. Using particle counters for leak detection is a commonly used, intuitive, and practical method.
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