Coalescent elements separate two liquid phases with different characteristics of density, viscosity and IFT (interfacial tension). Coalescer elements are manufactured with several filter media layers in pleated configuration to provide the initial separation of the dispersed phase from the mainstream. Separated drops travel to the surface of the cartridges, where the external agglomeration layer coalesces the separated liquid into larger droplets. These dislodge when they become heavy enough to be separated from the mainstream by gravity. Consequently, the separated phase is collected on the filter bottom by settling.

The separation efficiency achievable depends and the characteristics of the primary liquid and the dispersed phase to be separated. The design of the coalescing cartridges provides high separation efficiencies in those applications where traditional fibreglass cartridges are inefficient.

Using fluoropolymer, nylon or polyester coalescing media ensures high separation capacity even in the presence of amines, ammonia, acidic solutions, and naphtha with a high aromatics content (pyrolysis of gasoline), solvents, hydrogen peroxide, etc.