Coalescing filter media

Glass microfibres in the 0.5-0.75 pm diameter range usually yield the best results as a coalescing filter medium. The depth of the fibre bed and the void space to fibre space ratio, are of paramount importance to the proper operation of a coalescing filter. 

Either on a continuous oily film, if it is established in contact with a granular medium (sand, anthracite) and this is the case for granular coalescers or even filters. 

However, in upflow filtration on a noncompact granular medium, the aim is to associate the cyclic filtration of SS retained at the bottom of the filter bed with the limited and deliberate migration of oil. This corresponds in fact to the enlargement and breakaway of the thick oil film which has fed on the coalescence of HC droplets on the sand walls. 

Prefllter elements are made from a specially developed synthetic fibre medium, which is pleated, with the folds separated by means of spacers. The structure provides a good dirt-holding capacity, eliminates element distortion, and ensures that the complete filter area is utilized to maintain maximum flow. In addition to removing particulates down to 5 pm, the prefllter protects the coalescer element from excessive quantities of particulate contaminant. This is especially important in applications treating diesel fuel, where pipe scale, rust, waxes and asphaltines might otherwise block the fine pores of the coalescer element. 

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