Patent ID: 8104622

Claim:
A cyclone, comprising: a separating section having a first open end with a larger radius and a second end having a smaller radius; an underflow outlet positioned at the second end of the separating section; an inlet head positioned at the first open end of the separating section, the inlet head further comprising; a feed chamber having a continuous, uninterrupted inner side wall; a top wall at one end of the inner side wall; an open end at the other end of the side wall opposite said top wall, the open end being of circular cross-section with a central axis; an inlet port adjacent the top wall for delivering material to be separated to the feed chamber, the inlet port having a feed height dimension H 1 in the direction of the central axis; an overflow outlet in the top wall which is coaxial with the central axis; and a vortex finder at the top wall extending into the feed chamber in the direction of the central axis a distance L 1 from the top end wall; a feed inlet zone in the continuous, uninterrupted inner side wall of the feed chamber having an upstream end adjacent the inlet port and a downstream end extending away from said inlet port in a direction away from the top end wall, the feed inlet zone being defined by a volute having a volute axis extending around the continuous, uninterrupted inner side wall and including a first sector in which the volute is generally at right angles to the central axis and a second sector in which the volute extends around the continuous, uninterrupted inner side wall away from the top end wall and generally in the direction of the central axis a distance D, said second sector descending from the horizontal plane and extending in the direction of the central axis over a distance D ranging from 0.25×H 1 to 1×H 1 for every 90° of progress around the continuous, uninterrupted inner side wall; and wherein the distance from the volute axis to the central axis decreases with the progression of the volute around the continuous, uninterrupted inner side wall in a direction away from the inlet port.