METHOD AND DEVICE FOR CONTINUOUS EXTRUSION OF FILTER ELEMENTS Russian patent published in 2001 - IPC

FIELD: processing by extrusion, in particular, methods and devices for continuous extrusion of porous filter elements on the basis of activated carbon material. SUBSTANCE: the filter elements are manufactured from activated carbon fibers, granular active carbon at a relation of the components within 1:100 to 20:100 by mass, and polymeric binder in the form of fibers, in the form of a mix of fibrous polymers, or in the form of a mix of powdered and fibrous polymers. The method consists in mixing of the components in two stages, feed of the mix to a vessel, movement of the mix in the vessel at the rotary speed of the screw conveyer with a successive heating of it above the melting point of the polymeric binder and formation of the porous structure. As a result, an increase of the density occurs in thickness of the porous structure in the direction from the periphery to the center of the structure in the zone of the variable gap between the ridge of the screw conveyer and the inner surface of the vessel. Subsequent movement of the formed structure is effected in the gap between the divergent taper surfaces of the means connecting the output end of the vessel to the extrusion head for preservation of the formed structure in the gap and formation of the porous element at a rotary speed of the extrusion head core at a relation between the rotary speed of the core and the rotary speed of the screw conveyer within 0.001 to 0.99. The device for continuous extrusion of filter elements has a means for charging of the mix, a vessel with a means for mix feed communicating with the means for charging of the mix, a screw conveyer located coaxially with the vessel over its entire length and provided with a spiral ridge. The ridge is made with a gradual decrease of its width in the direction of withdrawal of the mix to the extrusion head. The pitch of the ridge front wall is less than the pitch of the rear wall. The device is also provided with vessel heaters, extrusion head positioned in the longitudinal axis adjacent to the vessel, core and a means connecting the output end of the vessel to the extrusion head. The conical transitions of the means from the vessel to the extrusion head matrix are made with a shift towards the extrusion head matrix are made with a shift towards the extrusion head relative to the conical transitions from the screw core to the extrusion head core. The angle of the taper surface of the transition from the vessel to the extrusion head matrix exceeds the angle of the taper surface of the transition from the screw core to the extrusion head core. The latter is fastened on the screw core with provision of free rotation relative to the screw. EFFECT: reduced pressure loss at preservation of filtering properties and mechanical strength of filter elements. 16 cl, 3 dwg