Fluidizing apparatus with foraminous member

Claim 1

In a material fluidizing apparatus comprising at least two communicating reaction chambers, each reaction chamber being separated from the next adjacent one by a foraminous member, and means for maintaining a recirculating cocurrent flow of gases and solid particles through said reaction chambers, the improvement wherein said foraminous member is a concavo-concave structure having a plurality of frusto-conical openings extending therethrough to permit continuous passage of said flow of gases and solid particles from a first reaction chamber to a second adjacent reaction chamber and to produce a pressure drop across said foraminous member from 0.5 to 5.0 psi, said frusto-conical openings being disposed in said concavo-concave structure so as to provide a pattern of spaced substantially circular cavities on the inlet side and the outlet side of said concavo-concave structure, the diameter of said cavities on the inlet side of said concavo-concave structure being from 25 to 100 times greater than the average particle size of said solid particles, the diameter of said cavities on the outlet side of said concavo-concave structure being from 2 to 10 times greater than the diameter of said cavities on the inlet side of said concavo-concave structure, the average thickness of said concavo-concave structure being from 1 to 20 times the diameter of a cavity on the outlet side of said concavo-concave structure, and the percentage of the area of the outlet side of said concavo-concave structure defining said frusto-conical openings being at least 70% of the total area of said outlet side of said concavo-concave structure.