Vertical type pulverizing and classifying apparatus

Claim 1

A vertical type pulverizing and classifying apparatus comprising; a pulverizing chamber (3), a pulverizing rotor (1) mounted in the pulverizing chamber (3) to be rotatable on a vertical axis (P), a material feeder (4) and a material carrying gas feed duct (10) both connected to the pulverizing chamber (3), a guide ring (5) mounted in the pulverizing chamber (3) directly over the rotor (1) to be substantially coaxial with the vertical axis (P), the guide ring (5) defining a gas stream ascending passage (8) circumferentially thereof and a gas stream descending passage (9) inwardly thereof, a classifying blade rotor (13) rotatable substantially on the vertical axis (P) to provide a secondary classification of fine particles of a material under treatment resulting from a primary classification effected in the gas stream descending passage (9), a collecting passage (14) for removing fine particles separated out by the classifying blade rotor (13), and a return passage (17,18) for returning coarse particles to the pulverizing chamber (3), CHARACTERIZED IN THAT a conduit is provided to be substantially coaxial with the vertical axis (P) for receiving fine particles of the material from the gas stream descending passage (9) and sending the fine particles to a classifying chamber (12) housing the classifying blade rotor (13), and the return passage (17,18) includes a floating chamber (17) defined circunferentially of the conduit (11) to receive the coarse particles descending from the classifying chamber (12), and a transfer duct (18) for feeding the coarse particles from the floating chamber (17) to the pulverizing chamber (3).

Claim 6

An apparatus as claimed in any of of claims 1 through 4 characterized in that the transfer duct (18) is connected to the material feeder (4), the coarse particles being fed from the floating chamber (17) to the pulverizing chamber (3) by way of the material feeder (4).