Patent ID: 7243868

Claim:
A hammermill comprising: a housing having an inlet end, a discharge end, a sidewall extending between the inlet end and the discharge end, a longitudinal axis, a primary reduction chamber, and a secondary reduction chamber adjoining the primary reduction chamber, the sidewall proximate the inlet end of the housing defining an inlet opening, wherein, in the secondary reduction chamber, the sidewall of the housing defining an enclosed work space, wherein, in the primary reduction chamber, the sidewall and the inlet opening define a partially enclosed work space; a rotor assembly disposed within the housing for rotation about the longitudinal axis of the housing; a plurality of hammers coupled to the rotor assembly and disposed in the primary and secondary reduction chambers, respectively, each hammer of the plurality of hammers comprising: an impact end, the impact end having a proximal end, a spaced distal end, and a pair of opposing side edges extending between the proximal and distal ends, at least one of the side edges defining an impact edge extending for at least a portion of the side edge, wherein the impact end has a hammer longitudinal axis that is angled with respect to the longitudinal axis of the hammermill, at least one of the side edges of the impact end being substantially parallel to the hammer longitudinal axis; a connection portion constructed and arranged for coupling to a portion of the rotor assembly; and a shank portion extending between the impact end and the connection portion, the shank portion having a first shank surface extending to a first shank edge and a second shank surface extending to a second shank edge, the first and second shank edges extending between the connection portion and the impact end, wherein the first and second shank surfaces are angled with respect to the longitudinal axis of the hammermill; and an attrition plate assembly secured to the sidewall within the primary and secondary reduction chambers, respectively, the attrition plate assembly arranged such that the hammers disposed in the primary and secondary reduction chambers are spaced from and overlie a portion of the attrition plate assembly.