Abstract: A plasticating screw having improved mixing capability for polymer blends comprises a feed zone having a helical flight defining a solid material feed path, a compression zone for converting the solid material into molten material having a helical channel of variable depth, a waved melting zone for breaking up solid agglomerations and distributing them equally in the liquid melt, a spiral mixing zone that traps large agglomerations and contaminants, and a second melting zone for completing melting the material and for creating a substantially homogeneous melt. A method for mixing plastic material that has been at least partially plasticized and contains inhomogeneities is also described.

Abstract: The improved check valve assembly includes a cylindrical barrel, a rotating and reciprocating plasticizing feed screw in said barrel, a screw tip or head portion downstream of the feed screw and connected thereto with the feed screw feeding heated thermoplastic material to the screw tip which in turn feeds the material externally of the screw tip, a check valve assembly between the feed screw and the screw tip including a sliding ring inside the barrel, a first sealing surface of the ring sealable against the feed screw operative to block communication between the feed screw and screw tip, and means operative to seal the ring against the feed screw upon rotation of the feed screw.

Abstract: The present invention relates to a static mixer for generating a substantially homogeneous media stream. The mixer has a series of angularly offset mixing elements with each element comprising a central boss portion, a plurality of ribs extending radially from the boss and defining with the periphery of the boss a plurality of substantially pie-shaped segments through which the media stream flows, and a plurality of webs for dividing each segment into two substantially equal flow areas. Each web has a first edge extending substantially radially and a second edge extending substantially circumferentially and is twisted through approximately 90.degree. from the first edge to the second edge.

Abstract: The present invention relates to a barrier screw having improved solids conveying capability. The barrier screw comprises a feed zone having a helical primary flight defining a solid material feed path, a transition zone for converting the solid material into molten material having a solids channel and a melt channel, and a metering zone for mixing molten plastic material from the melt path. In the feed zone, the helical flight defining the feed path is characterized by a substantially constant leading edge pitch and a trailing edge pitch which causes the thickness of the flight to increase as one moves along the screw barrel toward the beginning of the melt channel in the transition zone.

Abstract: A compliant bearing assembly for use in a precision slide is constructed so as to permit fine adjustment of engagement between a sliding bearing member and a shaft so as to effect minimum clearance and minimize vibration. The bearing member comprises a resilient arcuate plate or sleeve or a plurality of resilient plates, the or each plate being backed by an isotropic elastomeric medium confined between abutment stops. One of the abutment stops is adjustable for varying the displacement of the medium, thereby to displace the resilient plate inwardly against the shaft.