Ambient air typically contains water vapor (humidity), some particulate matter (dust), and other vapors and gases (fumes from volatile chemicals, exhaust from vehicles, etc.).The typical air compressor’s intake filter is designed to handle particulate matter - for the purpose of keeping abrasive airborne particles from damaging the compressor. Intake filters are commonly sized to catch particulates from 5 to 20 microns in size. However finer tuned filters may be required at the point of use.When compressed air leaves the compressor it has picked up some passengers including oil aerosols, rust particles (from the tank and piping), carbon particles from the compressors valves and intercooler (the result of burnt oil), and metallic particles from compressor wear. Selecting the correct compressed air filter to catch these contaminates will protect your equipment and help ensure their long life. The filtration experts at Cal Supply will be happy to assist you in proper filter selection...
Direct Interception Filters
Direct Interception is analogous to the screen on your windows at home. If an insect tries to get through the screen it is physically stopped from doing so. If it starts raining, however, you will get wet. If someone left a car running outside of your window you will smell exhaust fumes.
A particulate filter in your compressed air system, then, will catch solids larger than its’ pore size, but small liquid aerosols and vapors will pass through it. These filters are available in particle sizes of 1 to 40 microns. Pressure drop is low, about 1 PSI.
Coalescing is the process by which small aerosols are caused to group together and form larger droplets which are heavy enough to remove from the air stream. The elements in these filters are made from fine strands of fiberglass wound in such a way as to present progressively smaller gaps for the aerosols to try to pass through. When an aerosol hits a strand, it sticks to it. As other aerosols hit the strand they all run together and form larger droplets. The weight of these droplets causes them to drain to the bottom of the element and finally fall into a collection sump for drainage. Coalescing filters can remove particles and aerosols down to 0.01 micron in size. Depending on the fineness of the element, pressure drop can range from 2 PSI to 5 PSI.
Adsorption filters are commonly used to remove hydrocarbon vapors from compressed air. These vapors give the compressed air an oily odor. The principle involved is charcoal’s affinity to adsorb hydrocarbons. Just as a magnet attracts iron, charcoal attracts oil vapor. Unfortunately, the charcoal can hold only so much oil vapor, and when it’s become saturated the attraction stops. When this happens, the odor will appear and the element must be replaced. Adsorption filters are used for breathing air and for applications where compressed air is exhausted into a confined space where the odor of oil would be objectionable. Because these filters have a limited life span they are installed after all other filtration and cleanup equipment. They have a very low pressure drop.
Air Line Filters
Air Line Filters are commonly used at compressed air outlets and are designed to catch liquid water and contaminants from the piping. Elements are commonly 5 to 40 micron in pore size. These filters are available in sizes from 1/8” NPT to 2” NPT.
Air Inlet Filters
Air Inlet Filters are used to prevent airborne contaminants from entering the compressor and reduce noise. Cal Supply offers a wide variety of models and sizes both open and silenced.
These stainless steel filters are used in laboratory and food applications. They feature elements that are validated for the desired filtration efficiency and capable of being sterilized.
Vacuum Filters have threaded inlets and outlets so they can be installed in vacuum lines. CAl SUpply offers several types of elements readily available to meet your needs.