In a high vacuum setting, traps and filters may be installed on a vacuum foreline, but each has a different function:
Traps: A trap is a device that is designed to capture vapors and gases.
Filters: A filter is a device that is designed to capture or reduce particulates, dust, smoke, and aerosols. A common filter function, for example, is to capture the oil mist (an aerosol) that is discharged from the outlet of an oil-sealed rotary vane mechanical pump.
