Patent ID: 9605331
Date: 2017-03-28
CPC Classifications: C21D,F27B,F27D

Claim:
1. A batch annealing furnace for coils configured to anneal a coil in which a steel sheet is wound, the batch annealing furnace comprising: a coil support base on which an end face of the coil is mounted and that supports the coil with an axis of the coil being upright; an inner cover that covers an entire body of the coil mounted on the coil support base; and a cooling pipe that extends downward from an upper part of the inner cover to a cavity of an inner peripheral part of the coil mounted on the coil support base and cools the coil from an inner surface side by passing a coolant through inside of the cooling pipe, wherein the cooling pipe comprises a double pipe comprising a cylindrical inner pipe and a cylindrical outer pipe that surrounds the inner pipe, the inner pipe serves as an introduction pipeline that introduces the coolant from the upper part of the inner cover toward the coil support base, and an area between the outer pipe and the inner pipe serves as a return pipeline that returns the coolant from the coil support base toward the upper part of the inner cover, and wherein at a location where a direction of flow of the coolant passing through the introduction pipeline and the return pipeline changes, a bottom plate having a semispherical shape convex downward whose diameter is half the radius of the outer pipe or more reverses the direction.