Uniform shear valve for an extrusion machine

Abstract

A uniform shear valve for an extruder machine includes a body having a generally annular wall that defines an interior area extending along a longitudinal axis thereof. The interior area extends between an inlet proximate a first end of the body and a second end of the body. The second end is opposite the first end. The body has a first bore extending through the wall along a traverse axis substantially perpendicular to the longitudinal axis at a first position and second position. A flow control member is sealingly and slidingly positioned partially in the first bore at the first position and extends out of the body. The flow control member defines a first seat on an end thereof. An outlet is located in the first bore at the second position. A second seat is positioned proximate the outlet and is concentric with the first seat along the traverse axis. A uniform flow area is defined by a gap between the first seat and the second seat.

What is claimed is: 
     
       1. A uniform shear valve for an extruder machine comprising:
 a body having a generally annular wall that defines an interior area extending along a longitudinal axis thereof, between an inlet proximate a first end of the body and a second end of the body, the second end being opposite the first end, the body having a first bore extending through the wall along a traverse axis substantially perpendicular to the longitudinal axis at a first position and second position, 
 a flow control member sealingly and slidingly positioned partially in the first bore at the first position and extending out of the body, the flow control member defining a first seat on an end thereof; 
 an outlet located in the first bore at the second position; 
 a second seat positioned proximate the outlet and being concentric with the first seat along the traverse axis; and 
 a uniform flow area defined by a gap between the first seat and the second seat. 
 
     
     
       2. The uniform shear valve of  claim 1 , further comprising an opening in the body at the second end and a plug positioned in and sealing the opening, the plug defining a second bore therethrough that is concentric with the traverse axis, the seat being formed in the second bore. 
     
     
       3. The uniform shear valve of  claim 2 , wherein the plug defines a third bore aligned with a longitudinal axis of the body, the third bore comprising a tapered surface extending from an inlet of the third bore. 
     
     
       4. The uniform shear valve of  claim 1 , wherein the flow control member is selectively positionable to vary a magnitude of the uniform flow area. 
     
     
       5. The uniform shear valve of  claim 1 , wherein the uniform flow area is configured to eliminate melt fracture and melt memory effects in a fluid flowing therethough.