Abstract: An extrusion system, for example for extruding a food product, that includes: an extruder, which propels extrudate through an outlet of the extruder; and a valve. The valve includes: an inlet, which receives extrudate from the extruder outlet; a main conduit, which extends from the inlet to a main outlet; a dumping conduit, which extends from a junction with the main conduit to a dumping outlet; and a flow control member, which is operable to move between: a plurality of flow controlling positions, in which extrudate is directed to the main outlet, with the flow control member providing, for each flow controlling position, a respective amount of impedance to flow along the main conduit; and a flow diverting position, in which extrudate is directed along the dumping conduit to the dumping outlet.

Abstract: The utilization of an air cyclone classifying method to effectively separate out a low ash fraction, containing less than 11% by weight of non-protein material, from rendered animal meal. A yield of low material greater than 50% by weight is recovered as usable canine and feline food. The method involves the creation in a first cyclone separator of a double vortex air cyclone having a descending external air vortex and a rising internal air spire; wherein an upper chamber therein is equipped with a rotary particle rejector. The rendered animal meal infeed is fed into the rising air spire which entrains and carries the low ash fraction through the rotary particle rejector, to a second cyclone air cleaning device; wherein the low ash material is recovered from the entraining air. The larger and denser high ash particles are recovered from the first cyclone separator.