Patent ID: 8894811

Claim:
A method of forming a dilute water slurry for water felting a basemat for an acoustical ceiling tile comprising delivering a bale of compressed mineral wool with a density of at least 8 lbs. per cubic foot at an unbaling station, releasing a binding holding the bale in compression, mechanically separating the fibers of the mineral wool bale with mechanical instrumentalities and optionally an air stream at stations in a path between the unbaling station and a mixing tank, the instrumentalities or air stream and, optionally, a conveyor or conveyors being arranged to conduct the separated fibers along the path to an inlet of the tank, arranging the fiber separating instrumentalities to separate the fibers to a generally uniform density of less than 2 lbs. per cubic foot prior to passage of the fibers through the tank inlet, and causing the separated mineral fibers to pass into the mixing tank for contact with water suspended binder, mechanically mixing a binder and optionally other constituent materials used in the production of a wet felted basemat in the tank by a rotating blade prior to introduction of the separated mineral fibers into the mixing tank whereby modulation and breakage of the separated mineral fibers is reduced.