摘要 |
PURPOSE:To achieve uniform cooling in the circumferential direction of a metal tube by passing said metal tube through the annular tunnel injecting cooling medium from a plurality of headers and having a desirable diameter. CONSTITUTION:The sixteen headers 2 arranged such that the headers are positioned in the axial direction of an objective metal tube 16 to be cooled and are simultaneously placed at same interval in a circumferential direction are equally divided into three parts in height-direction, whereby the difference of water- head is reduced to one third. The cooling medium-injecting angle of every divided unit of a plurality of the headers 2 divided into three parts is simultaneously changed by the same angle in the vertical or almost vertical plane to the axis of said metal tube 16. Thus, the annular tunnel injecting the cooling medium in the specified direction of the radial direction and having a desirable diameter, is formed. The metal tube 16 is cooled, passing the metal tube 16 through this annular tunnel. |