-It is unsoiling of filtering surface because film of liquid is formed between filtering surface and soiled flow. Separation of liquid phase is taken place before passing through the filter, hence pores of filter remain clear. In the all known designes of American, French and others firms, the separated phase passes through the filter and settles within porous structure, therefore, difference of pressure increases in the process of exploitation.
-Since the flow is twisted, film of liquid is allocated even on the filtering surface and pours down from filtering surface. Filter is installed in vertical or horizontal position.
-Since filter is installed on the punched frame, the apparatus works under pressure 250 atm (3500 psia).
-The apparatus works stability, when quantity of liquid is increased. There is restriction on minimal quantity of liquid. Efficiency of the apparatus isn’t worse, if quantity of liquid in flow more than design minimal quantity in five times and more. Difference of pressure of the apparatus isn’t very grown. In the all known designs the excess of liquid above design quantity difference of pressure very increases, period of work for filter between replacements reduces and efficiency of cleaning.
-The apparatus works stability, if solid particles are presented in the flow. Solid particles are separated together with liquid phase  on outside surface of filter, don’t pass through porous space and don’t litter filter.
-Filter ФЭП is coalescer because porous channels have narrow and enlarged sections. For intensification of coalescence effect, two-stage structure is used, where first stage is coalescer and second stage is separator.
-The apparatus works with self-cleaning effect of filter surface from solid particles untill five years.
-The special advantage of filter-separator is high efficiency work by exceeding expenditure of gas.

-The apparatus is asserted by patents in force granted by Russia (#869796), Germany (#142500), Canada (#1126174), France (#7906860), USA (#4251375).