Abstract: There is provided an apparatus for measuring the shear stress of a fluid wherein the shear stress is determined by measuring the movement of one end of a substantially rigid lever with the other end having the active face forming the shear stress measurement surface.

Abstract: A method and apparatus for making multi-layered plastic tube reinforced with fibers by a co-extrusion process. The method and apparatus provide more specifically a multi-layered plastic tube with an intermediate layer thereof having discrete fibers where at least a major portion of the fibers is oriented to extend predominantly in a general direction lying between the circumferential and the longitudinal axis of the tube with the orientation of the fibers being generally the same throughout the thickness of the intermediate layer.

Abstract: There is provided a method and apparatus for measuring the viscosity and other rheological properties of a viscoelastic fluid wherein the fluid flows through a fluid channel which has a plate mounted therein, the plate having a surface which is substantially parallel to a wall surface defining the channel and the plate is moved with respect to the wall to thereby subject fluid between the wall surface and the plate to a shearing deformation, and subsequently measuring the shear stress of the fluid at the wall when subjected to the shearing deformation.

Abstract: A method is disclosed for measuring the shear stress of a viscoelastic fluid wherein the force measured on a plate exerted by the fluid flowing coplanar therewith is measured.