Abstract: A wet-type rotary sand classifier of this invention is provided with a plurality of helicoid blades which are secured onto the inner surface of the rotary drum along the entire length of the drum with their respective rear ends terminating at the rear end plate of the rotary drum at a desired angle relative to the axis of the rotary drum. Due to the above construction, the sand which has settled onto the inner bottom surface of the rotary drum can be transferred to the rearmost corners formed by the helicoid blades and the rear end plate whereby the thus transferred sand is raised upward by the helicoid blades corresponding to the rotation of the drum without carrying the water dams which are usually formed in the conventional wet-type sand classifier.

Abstract: A rotary drum-type sand classifier of this invention is provided with a desired number of rows of sand discharging mechanisms at the rear end thereof.Between each pair of sand discharging mechanism, a water cleaning chamber is formed where the classified sand is cleaned with water fed from the rear outlet of the drum. Due to the above construction, the sand classifier of this invention can conduct the classifying and cleaning of sand to be produced simultaneously and efficiently.

Abstract: A wet-type sand classifier is characterized by having a unique cone-shaped and sand-discharging means which is disposed at the outlet of the rotary drum and is employed instead of a conventional belt conveyor means to improve the classification efficiency of the apparatus.