Axial flow rotary separator

DETAILED DESCRIPTION Accordingly it is an object of the invention to retain, in an axial flow rotary separator, material handling and mechanical efficiency advantages provided by a rotor whose finger-like elements engage the crop material mat only intermittently but which, while in engagement, propel it positively (at least circumferentially) while at the same time contributing to its axial displacement, but to use a rotor and separator casing combination which is inherently lower in cost and more reliable than known separators of this type.
This object may be realized in a separator arrangement in which the separator casing has fixed internal helically disposed guide surfaces and surrounds a rotor characterized in that at least the radially outward portions of its finger-like crop engaging elements are displaceable or resiliently yieldable, at least axially, relative to the rotor frame or body.
The casing shape and the rotor disposition within it are such that, as the rotor rotates, each finger approaches and recedes from the casing wall.
In operation, rotor speeds and material flow rates are normally such that, essentially, crop material is maintained, in an annular mat of predetermined maximum thickness in contact with the casing wall, so that each finger penetrates and propels a mat portion only periodically, defining a zone or arc of engagement.
Casing helical guide surfaces are disposed so that preferably, but not essentially in some portion of the zone of engagement, each mat portion is deflected axially downstream, if necessary carrying the displaceable finger outward portion downstream with it so that it is displaced relative to the rotor frame.
Preferably the fingers are designed to be easily displaceable, at least axially, offering negligible resistance to axial movement of the crop material mat portion.
The aggregate effect of a plurality of fingers on the rotor cooperating with suitably disposed guide surfaces is of course to propel a received body of crop material in an annular mat generally in contact with the casing spirally downstream