What Is a Filter?
Filters are pieces of equipment that remove or reduce the function of specific parts of a substance.
Familiar examples include water filtration systems and vacuum cleaner exhaust vents. Filters are also used to reduce sunlight, intensity, and blue light from computer screens.
How Filters Work
Filters used for air, water, and other fluids basically function as filtration devices, and most of them are made of woven fibers or metal mesh, called elements, through which the fluid passes.
The smaller the gap between the elements, the cleaner the fluid, the more small particles can be removed, but the greater the resistance, the lower the flow rate. Also, if the element becomes clogged, the flow itself will stop. Conversely, if the gap is enlarged to increase the flow rate, small particles will pass through the element.
In selecting an element, it is important to determine how much foreign matter can be tolerated and to calculate how much flow must be maintained.
To detect clogging of an element, install pressure gauges on the IN and OUT sides of the filters and look at the pressure difference to see if there is any clogging. If the IN side pressure is high and the OUT side pressure is low, this indicates that clogging has occurred and no fluid is flowing to the OUT side.
Types of Filters
The following is a list of typical types of filters, divided into those for liquids and those for air.
Filters for Liquid
- Bag Filters
Filters with a bag-shaped cloth element set inside a metal case. It can filter a large volume of fluid. - Filters Wound With Thread
Filters made of fiber that is made into thread, and then the thread is wound around a core to form a roll. Even the smallest foreign matter can be removed. - Y-shaped Strainer
Filters with a metal mesh set in a Y-shaped metal case. It can remove larger foreign matter.
Filters for Air
- Air Filters
Filters to remove foreign matter in the air. Filters include line filters with large capacity to remove larger foreign objects and mist collectors to remove oil in the air. - Exhaust Filters
Filters that filter used air when it is released to the atmosphere. There are exhaust cleaners that filter large volumes of waste and silencers that reduce exhaust noise.