Patent ID: 7537674

Claim:
A closed system for pulp de-inking process for recycled paper comprising: a) a closed flotation cell in conduit communication with a source of pulp slurry having an injector assembly interdisposed within a pulp slurry feed line for injecting air into said pulp slurry, said flotation cell containing a foam separator, said flotation cell functioning without the use of defoamer chemicals; b) a sludge tank in conduit communication with the flotation cell for receiving contaminated foam slurry through a reject port located above said foam separator; c) a moisture trap in conduit communication with the sludge tank for receiving moisture from a vent located at a top of said sludge tank; d) a reject tank connected through drains to bottoms of the sludge tank and moisture trap, said moisture trap incorporating a trap to maintain vacuum within said system; and e) an air-flow control system having a conduit providing communication between the moisture trap and the injector assembly for recirculating air from said moisture trap back to said injector assembly.