Patent ID: 7381364

Claim:
A gas jet cooling device, comprising: a cooling chamber; windboxes being disposed in said cooling chamber on both the sides of a metal strip to be cooled in a manner of interposing the metal strip in between and moving the metal strip in a traveling direction, said windboxes blowing a cooling gas toward the metal strip to be cooled through nozzles so as to cool the metal strip, wherein width of the area of the windboxes having the nozzles is substantially equal to the width of the metal strip to be cooled; and means for cooling gas introduced from said cooling chamber and then supplying the cooled gas to said windboxes as the cooling gas, wherein the cooling chamber is arranged such that the distance between the tips of the nozzles on each of said windboxes and the metal strip to be cooled is not more than ten times the diameter of said nozzles, and the length of each of said windboxes in the traveling direction of the metal strip to be cooled is not more than two thirds of the width of the area of the windboxes having the nozzles.