A Coalescer is a technological device performing coalescence. They are primarily used to separate emulsions into their components via various processes; operating in reverse to an emulsifier. A coalescer can be divided into mechanical and electrostatic coalescers. Mechanical coalescers use filters or baffles to make droplets coalesce while electrostatic coalescers use DC or AC electric field.

The application of this filter separator is the removal of solid impurities and Presentational. Of condensate, also in miss form, out of air and gas streams. The pressure vessel is equipped with coalescer elements. The elements consist of various layers of packed glass fiber. Fine and finest droplets are carried by the gas stream into these layers. These droplets encounter fibers stick down to them and run down. On the way downwards they meet other droplets and agglomerate to larger droplets which are flowing down inside the fiber glass layers also. To achieve the high separation efficiency the gas must flow from the inside to the outside of the coalescer elements. If no solid particles are present in the gas stream the replacement of the elements is not required.