In-line filter for gases

Claim 1

An in-line gas filter unit comprising in combination, a head defining a cavity having an inlet port for gases to be filtered and a discharge port for outlet of filtered gases, barrier means in said head between said ports, an outer transparent cup-shaped container having means on the open end separably connectable to said head for communication with only said inlet port, said container depending from said head and having a plurality of circumferentially spaced relatively short radial ribs extending uniform distances upwardly from the lower end of said container, an open-ended transparent inner tubular container of lesser diameter than said outer container positioned coaxially therein to provide an annular filter space therebetween, said head having an annular seat and the upper end of said inner container being received within said seat for communication only with said discharge port in said head and the lower end being axially spaced from the bottom of said outer container, sealing means in said seat engaging said upper end of said inner container, relative coarse filter material filling said annular space between said lower end of said inner container and an intermediate position between the ends of said inner container, thereby rendering the portion of said inner container between said upper end thereof and said coarse filter material visible through said outer container, an additional filter cartridge of desiccant filter material contained in a porous enclosure positioned within said inner container and extending substantially between the opposite ends thereof and in tight engagement with the inner surface thereof to insure passage of gases through said desiccant material for additional filtering thereby, upper and lower perforated rigid discs positioned respectively flatly across the opposite ends of said inner container and the perforations therein being sufficiently large to permit ready passage of gases therethrough without impeding the movement of said gases as the same pass to and from said desiccant filter material of said additional filter cartridge, the lower perforated rigid disc being supported upon said radial ribs and commonly supporting the lower ends of said coarse filter material and said additional filter cartridge, whereby the condition of said desiccant filter material is visible through said outer container and said upper portion of said inner container to indicate the need to replace said additional filter when necessary and gases pass downwardly through said coarse filter material and upwardly through said desiccant filter material in passage to said discharge port free of contaminating moisture and vapor.