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US 4,395,212 AGranted
Screen-change device for extruders
AssigneeWerner & Pfleiderer
InventorFriedrich Lambertus
Life of this patent
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AssigneeWerner & Pfleiderer
InventorFriedrich Lambertus
Estimating the term…
A screening apparatus for molten plastic material flowing from an extruder comprising a housing mounted on the extruder and having a feed channel for flow of the plastic material therefrom and a slide member mounted for slidable movement in the housing with a clearance therebetween. The slide member contains replaceable screen elements adapted for being positioned in the path of flow of the plastic material flowing from the extruder to effect screening thereof. In order to seal the clearance between the slide member and the housing to prevent outflow of plastic material therefrom, a flange is mounted on the housing to surround the slide member with a gap therebetween. This permits normal free-sliding movement of the slide member in the housing. The flange contains cooling channels to permit flow of a coolant to cool plastic material in the gap and solidify the plastic material to prevent outflow of plastic material from the gap. The flange is mounted on the housing by thermal insulation which prevents cooling of the housing upon cooling of the flange.
Screening apparatus for molten plastic flowing from an extruder of plastic material, said screening apparatus comprising a housing adapted for being mounted on the extruder and having a feed channel for flow of plastic material from the extruder through said housing, a slide member, said housing having a borehole in which said slide member is slidably mounted with clearance, replaceable screen elements on said slide member for being discontinuously positioned in the path of the plastic material flowing from said extruder, and means for sealing the clearance between the slide member and said housing to prevent outflow of plastic material therefrom, said means comprising a flange on said housing surrounding said borehole and facing said slide member with a minimal gap therebetween to permit normal free sliding movement of said slide member, a cooling channel in said flange for flow of a coolant for cooling said flange to minimize said gap and to cool plastic material in said gap for solidifying said plastic material to prevent outflow of plastic material from said gap, and thermal insulation means between said flange and said housing for preventing cooling of said housing by the cooling of said flange.
Dependencies are inferred from the claim text.