초록 ▼

A method for cleaning thermoplastic material especially for reclaiming thermoplastic material from scrap material which includes in addition to the thermoplastic material, materials having a higher melting point than the thermoplastic, such as metal, thermosetting material, etc. The scrap material w

A method for cleaning thermoplastic material especially for reclaiming thermoplastic material from scrap material which includes in addition to the thermoplastic material, materials having a higher melting point than the thermoplastic, such as metal, thermosetting material, etc. The scrap material which has been treated to remove large particles of metal and/or other hard materials is heated and extruded to thereby provide a confined pressurized stream of melted thermoplastic material containing therein small metallic or other unmelted particles. A portion of the stream of melted material is filtered to provide a filtrate composed of melted thermoplastic material containing therein unmelted materials having a size less than a preselected size. The separated unmelted material remains in the stream and the flow rate of this remainder portion of the stream is controlled or metered so as to maintain the stream under pressure where it is being filtered whereby most of the melted thermoplastic material is caused to flow in the filtrate while the remainder portion carries away the separated unmelted material. The apparatus may be retrofitted on a conventional extruder by adding an extruder screw extension and a cylindrical screening means about the screw extension which will wipe the interior surface of the screen of contanimants. The metering of contaminant bearing stream is preferably by chilling the stream to a semi-solid state and grinding the semi-solid state stream. The preferred screen is formed of a punched plate formed into a cylinder and plated with an abrasion resistant material which covers the sharp edges of the holes with a rounded surface.

대표청구항 ▼

A method of cleaning contaminated thermoplastic material comprising the steps of heating thermoplastic material containing small pieces of contaminants to a temperature such that the thermoplastic material is melted but contaminants are not melted, extruding the heated material to provide a confined

A method of cleaning contaminated thermoplastic material comprising the steps of heating thermoplastic material containing small pieces of contaminants to a temperature such that the thermoplastic material is melted but contaminants are not melted, extruding the heated material to provide a confined stream of material under pressure, filtering a portion of said stream to provide a filtrate composed of melted thermoplastic material containing ummelted contaminants having a size smaller than a preselected size and controlling the flow rate of the remainder portion of said stream to maintain said stream under pressure where it is being filtered whereby most of said stream is caused to flow in said filtrate and said remainder of said stream carries away contaminants separated by said filtering step, said controlling of flow rate step including chilling the remainder portion to reduce the speed of its flow and removing the chilled material at a controlled rate.