In-line filter assembly for compressed air

Claim 1

An in-line filter device including first filter means having a first pad adapted to coalesce vapor or liquid particles contained in compressed air passing therethrough, into droplets, trapping means for trapping the droplets and thereby separating the droplets from the compressed air, and second filter means having a second pad through which is passed the compressed air which has passed said first filter means, the second pad being adapted to vaporize residual liquid particles remaining in the compressed air which has passed the first filter means, said in-line filter device comprising: a double-walled tube filter assemby including an inner tube and an outer tube which are disposed in radially spaced, and coaxial relation with each other, so as to define an annular space therebetween, one of said inner tube and said annular space being filled with said first pad, so as to provide said first filter means, while the other of said inner tube and said annular space being filled with said second pad, so as to provide said second filter means; an upper cap disposed in sealing engagement with an upper open end of said double-walled tube filter assembly, for fluid-tight communication therewith, said upper cap having an inlet opening which communicates with an upper open end of one of said inner tube and said annular space, and an outlet opening which communicates with an upper open end of the other of said inner tube and said annular space, said inlet opening receiving the incoming compressed air, while said outlet opening being adapted to deliver the filtered compressed air; and a lower cap disposed in sealing engagement with a lower open end of said double-walled tube filter assembly, for fluid-tight communication therewith, said lower cap having an enclosed space which communicates with lower open ends of said inner tube and said annular space, said enclosed space having a volume sufficient to reduce a velocity of the compressed air flowing into said enclosed space after passage thereof through said first filter means, said lower cap including a porous structure accomodated within said enclosed space, as said trapping means for trapping said droplets formed during passage of the compressed air through said first filter means, said lower cap further including drain means for discharging a mass of the droplets trapped by said porous structure, out of the filter device; wherein said porous structure for trapping said droplets consists of a honeycomb structure accommodated in a lower portion of said enclosed space within said lower cap, such that passages formed through said honeycomb structure extend vertically.