| 摘要 |
PURPOSE:To rapidly and uniformly perform the effect of cooling a steel plate with the movement of cooling water, by attaching blades having a specified configuration to the rotary shaft of an impeller for agitating cooling water provided in a water tank for quenching the steel plate. CONSTITUTION:An impeller 132 for moving cooling water is used to carry the cooling water at a high speed along a direction opposite to the running direction of a steel plate inside a water tank for rapid cooling in an apparatus for quenching the steel plate. Four pieces of blades 140 are provided at the periphery of the rotary shaft 136 of the impeller along the longitudinal direction of the rotary shaft 136 in the same intervals along its radial direction. The blades 140 are helically attached to the rotary shft 136 in a manner such that the angle alpha of torsion of the blades to a hypothetical plane including the axis of the rotary shaft 136 is made below 30 deg. from he standpoint vertical to the axis. The steel plate is uniformly rapidly cooled with excellent cooling efficiency without the stagnation of cooling water heated at a high temperature around the rotary shaft of the impeller 132. |
