Pneumatic filter
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A pneumatic filter is a device which removes contaminants from a compressed air stream. This can be done using a number of different techniques, from using a "media" type that traps particulates, but allows air to pass through to a venturi, to a membrane that only allows air to pass through.
[edit] Usage
It is now common to have various stages of filtration employed in a filter-regulator-lubricator form factor, usually with the different filter housings connected. Air filtration applications are diverse and include end-user sectors such as cleanroom environments, biomedical, analytical instrumentation, food processing, marine and aviation, agriculture, manufacturing, food and beverage packaging and a host of other uses.
[edit] Primary filters
Typical commercial pneumatic filters will remove particles as small as 5 micrometres (microns) from the air. The filters protect pneumatic devices from damage that would be caused by these contaminants. These contaminants include lubricant particles ejected by the compressor, dirt particles and small water droplets.
[edit] Secondary filters
Secondary filters are used for a variety of applications and can remove particles as small as 50 nanometres in size. These secondary filters can remove fumes, odors, vapor, mist, moisture, oil, and tiny particles from the air stream. In addition, special "point-of-use" air drying devices (called membrane air dryers) may be used to depress the pressure dewpoint by selectively condensing water vapor from compressed air in order to deliver a cleaner and dryer air supply before entering the equipment. Membrane air dryers, however, may be easily damaged thru any contact with liquid droplets (water or oil) so they should be protected with a high-efficiency coalescing (nano) air filter, positioned either immediately upstream or integrated within the membrane air dryer housing. Membrane dryers are mostly used with equipment which is especially sensitive to water vapor such as paint booths, 2-part mixing equipment (polyurethane sealants), polyurea dispensers, PUR-applicators (edge-banding equipment), laser-cutting machinery, CMM's, industrial ink-jet printers, or even for laboratory use.
There are a number of different manufacturers of pneumatic equipment, including air filters. Some examples are:
