company news about Filtration System

Any air introduced in the controlled zone needs to be filtered. Air filtration involves the separation of "particles" from airstreams. Their removal method is almost as diverse as the size ranges of the particulates generated. Understanding separation techniques requires an exact definition of what particles are. As particles become very small, they cease to behave so much like particles as they do gas phase molecules. It is difficult to tell whether such small particles are actually suspended in air (particles) or diffused throughout it (gas or vapor). The bottom boundary where particles act as true particles is about 0.01 micron. The normal theory of separation does not apply to particles below this size and removing them from air requires techniques reserved for gaseous materials. Particles above 0.01 micron are usually considered to be filterable. All air entering a cleanroom must be treated by one or more filters. High-efficiency particulate air (HEPA) and ultra-low penetration air (ULPA) filters are the most common filters used in cleanroom applications.

Air filters are constructed of filter media, sealants, a frame, and sometimes a faceguard and/or gasket.

1) Media is the filtering material. Common types of media include glass fiber, synthetic fiber, non-woven fiber, and PTFE. High efficiency filters use sub-micron glass fiber media housed in an aluminum framework.

2) Sealant is the adhesive material that creates a leak-proof seal between the filter media and the frame.

3) Frame is where the filter media is inserted. It can be made from a variety of materials including aluminum, stainless steel, plastic or wood.

4) Faceguard is a screen attached to the filter to protect the filter media during handling and installation.

5) Gasket is a rubber or sponge like material used to prevent air leaks between the filter and its housing by compressing the two together. Air enters the filter through the upstream side. It flows through the filter, contaminants are taken out of the air, and the ‘clean’ air exits through the downstream side. How ‘clean’ the air is on the downstream side depends on the efficiency of the filter.