PROCEDURE AND ORGANISATION FOR CIRCULAR STRENGTH TESTING INCLUDING ROTATION ROUND THE MOUNTAIN

摘要

Apparatus for producing tubular sheet material by extruding a fluid polymer material through a hollow centered die having an annular extending continuous or discontinuous extrusion orifice exit rotated about the die axis to discharge therefrom a continuous or discontinuous annular-form polymer structure which is collected on a generally cylindrical supported surface advancing through the hollow center of said die. The collected structure undergoes attenuation at an angle to the general extrusion direction because of the die exit rotation and consequently, has a grain therein extending at a significant angle, e.g. helically, to the general extrusion direction. The collecting surface may be formed separately from the support, e.g. by one or more endless belts passing either longitudinally or helical around the support so as to collectively define a cylindrical surface in the collection zone or combined with the support, e.g. as a solid toroidal shaped member having its lengthwise axis passing through the die center and advanced along that axis. The extrusion die can have an inlet channel extending generally around the exterior thereof into which the polymer material can be delivered in pressure-free fashion and vanes or grooves can be associated with the inlet channel to assist in feeding the polymer material to the die exit orifice.