Abstract: A screw conveyor having auxiliary blades (10), and a screw discharge decanter centrifuge. A hollow internal cylinder (4) is provided with a tapered section (11) and a straight section (7). Screw blades (6) are provided on the periphery of the inner cylinder (4), and several auxiliary blades (10) are provided between the screw blades (6), wherein the width of the auxiliary blades (10) is smaller than the pitch of the screw blades (6). Two adjacent auxiliary blades (10) are arranged in a staggered manner in a screw passage space to form a serpentine flow passage (15).

Abstract: A method for rapidly measuring the roller pass major semi-axis of a three-roller reducing mill to improve the outer-diameter precision and surface quality of a steel pipe includes selecting a corresponding value of the average diameter of an elliptical pass, a value of a first major semi-axis, and a value of a minor semi-axis according to a rack station number of a special numerical control lathe; calculating a value of a first line segment according to an elliptic equation, the obtained value of the first major semi-axis, and the obtained value of the minor semi-axis; calculating a value of a second major semi-axis according to the right-angle triangle theorem and the value of the first line segment; and measuring a value of the first dimension by attaching three claws of a three-claw internal micrometer to three roller gaps.

Abstract: A method for rapidly measuring roller pass major semi-axis of three-roller reducing mill, the method comprising the following steps: selecting a corresponding value of the average diameter of an elliptical pass, a value of a first major semi-axis and a value of a minor semi-axis from a three-roller pass data table according to a rack station number of a special numerical control lathe; calculating a value of a first line segment according to an elliptic equation, the obtained value of the first major semi-axis, and the obtained value of the minor semi-axis; calculating a value of a second major semi-axis according to the right-angle triangle theorem and the value of the first line segment; measuring a first size value by attaching three claws of a three-claw internal micrometer to three roller gaps; or attaching one end of inner calipers to any roller gap, and attaching the other end to the bottom of a roller arc opposite the roller gap to obtain a second size value.