Particle counter
However, employment of the condensation nuclei counter (CNC) technique would allow a higher detection sensitivity in particle sizes down to nanometre range.
Direct imaging is a technique that uses the light emitted by a laser as a source to illuminate a cell where particles are passing through.
The particles in the sample will block the light, and the resulting silhouettes will be imaged onto the digital camera chip.
Cleanrooms are used extensively in semiconductor device fabrication, biotechnology, pharmaceuticals, disk drives, aerospace and other fields that are very sensitive to environmental contamination.
The CPC and differential mobility particle sizers, including the scanning mobility particle sizer and fast mobility particle sizer, can measure aerosol concentration; the diffusion charger and electric low pressure impactor can measure surface area; the size selective static sampler and tapered element oscillating microbalance can measure mass.
This ISO Standard can be found through the non-profit organization, Institute of Environmental Sciences and Technology (IEST).
Liquid particle counters can be used to test the quality of drinking water or cleaning solutions, or the cleanliness of power generation equipment, manufacturing parts, or injectable drugs.
With a vision based system quick and efficient particle sizing can be done with ease and tremendous accuracy.
This computer based system can integrate into a database, alarming and may have e-mail capability to notify facility or process personnel when conditions inside the cleanroom have exceeded predetermined environmental limits.
A hand-held particle counter is a small, self-contained device that is easily transported and used, and designed for use with Indoor Air Quality (IAQ) investigations.
A primary use of aerosol particle counters is in the determination of contamination levels within a cleanroom or clean containment device.
Cleanrooms and clean containment devices maintain low levels of particulate-free air through the use of filters and are classified according to the number of particles permitted; the primary standard for cleanroom or clean air devices is ISO 14644-1, other local standards may also exist such as FED-STD-209E.
Particle counters demonstrate that these controls are effective, and the production environments are optimized for the quality required.
Air particle monitoring is required for ensuring the manufacturing environment is free from contamination level that will cause defects.
It is performed either for the entire cleanroom areas (ballrooms, bays and chases), or specific local controlled environments (tools and minienvironments).
The use of on-line continuous particle monitoring, either at the final water purification step or at the wafer point-of-use, provides process engineers the critical particle data needed to effectively manage the water purification and wafer cleaning processes.
Products such as integrated circuits require many process gases for: etching, deposition, oxidation, doping, and inert overlaying applications.
Impurities in these gas streams can create failures in critical processes and impact yield and throughput.
Non-reactive gases can be depressurized using a clean path gas diffusion device and tested using a portable particle counter.
Environmental design considers the contamination in various process steps, including: raw material purification, formulation of product, final filling and packaging.
Depending on the type of product being manufactured the level of clean controlled space is initially determined using the cleanroom classification standards, the higher the risk of contamination the cleaner the environment, e.g., aseptic filling is performed in an ISO 5 controlled environment, whereas terminally sterilized product is finished in an ISO 7 area (prior to final sterilization).
The primary concern for contamination is risk of adverse effects by the end user, a resultant demonstration of control, is an increase in production.
The general environments are also monitored for any microbial contaminants using traditional techniques such as settle plates and volumetric air samplers.
Compressed gases used in formulation, conveying and overlaying are required to meet the same standards for GMP compliance as all environmental air quality and should be tested at point of use.
Other industries also use particle counters to demonstrate either cleanliness of manufacturing environments or quality of finished product.
The application of hydraulic fluids vary from aerospace and turbine cooling and lubrication to heavy machinery.
Water is a universal product with an unlimited number of applications and can be contaminated due to intentional interactions with processes or unintentional and seasonal variances.
Particulates exist in the atmosphere at concentrations that can be deleterious to health, and have been proven to factor into causes of many airborne illnesses such as asthma.
The modelling of particulate data from particle counters distributed globally gives trend information to the state of quality of air and its migration.
