Method of separating products of different density and apparatus for carrying out the method

Claim 3

A method as claimed in claim 1, and directing said water upwardly through a plurality of openings in the bottom of the receptacle some of which are vertically directed and the remainder of which are upwardly obliquely directed in the direction in which the crushed plastic moves from end to end of the receptacle.

Claim 4

A method as claimed in claim 1, and feeding material removed from the upper part of a first said receptacle to a subsequent receptacle, and directing water downwardly against the material in the subsequent receptacle with a force sufficient to force heavier material downward but not lighter material.

Claim 5

Apparatus for separating scrap plastic from impurities, comprising means for crushing scrap plastic, means for feeding the crushed scrap plastic into a horizontally elongated receptacle containing water, means for moving the crushed plastic from one end to the other end in said receptacle while directing water upwardly in the receptacle at a velocity sufficient to entrain impurities and raise said impurities to an upper portion of the receptacle but insufficient to raise said crushed plastic from a lower part of the receptacle, said receptacle having at least two opposed side walls extending substantially full length of said receptacle which are flat and which converge upwardly thereby progressively to reduce the width of the receptacle in an upward direction so as progressively to increase the upward velocity of liquid moving in the receptacle substantially from said one end to said other end of the receptacle, means for removing said impurities from said upper part of said other end of the receptacle, and means for removing crushed plastic freed from said impurities from said lower part of said other end of said receptacle.

Claim 6

Apparatus for separating scrap plastic from impurities, comprising means for crushing scrap plastic, means for feeding the crushed scrap plastic into a horizontally elongated receptacle containing water, means for moving the crushed plastic from one end to the other end in said receptacle while directing water upwardly in the receptacle at a velocity sufficient to entrain impurities and raise said impurities to an upper portion of the receptacle but insufficient to raise said crushed plastic from a lower part of the receptacle, said receptacle having at least two opposed side walls extending substantially full length of said receptacle which are flat and which converge upwardly thereby progressively to reduce the width of the receptacle in an upward direction so as progressively to increase the upward velocity of liquid moving in the receptacle substantially from said one end to said other end of the receptacle, means for removing said impurities from said upper part of said other end of the receptacle, and means for removing crushed plastic freed from said impurities from said lower part of said other end of said receptacle.

Claim 7

Apparatus as claimed in claim 4, in which the receptacle is horizontally elongated and has openings in its bottom for the upward passage of water therethrough, some of said openings being vertically directed and the remainder of said openings being obliquely upwardly directed in a direction lengthwise of the receptacle.

Claim 8

Apparatus as claimed in claim 4, in which the bottom of the receptacle is horizontal and has openings therethrough for the upward passage of water, some of said openings being limited along their longitudinal borders by sharp edges and others of said openings being limited along one of their longitudinal edges by a sharp edge, the opposite edge being rounded.

Claim 9

Apparatus as claimed in claim 4, and an additional receptacle to which is fed said impurities from the first-mentioned receptacle, and a wetting manifold disposed above said further receptacle to create a descending current in said additional receptacle thereby entraining the heavier material downward but not the lighter material, means in said further receptacle for removing lighter material from the top of said further receptacle, and means in said further receptacle for removing heavier material from the bottom of said further receptacle.

Claim 10

Appparatus as claimed in claim 4, there being a plurality of said receptacles in series with each other, material from one receptacle being fed to the next receptacle, the water in the receptacles having progressively greater upward velocity in the direction of movement of the material from receptacle to receptacle.

Claim 11

Apparatus as claimed in claim 8, wherein the series of receptacles includes separate receptacles for the reception of the lighter and heavier materials respectively from the first said receptacle.