Flow change-over valve for the blowing of fluids into molten metal vessel

摘要

Disclosed herein is a flow change-over valve for the blowing of fluids into a molten metal vessel, which includes a housing provided with at least three inlet ports for different fluids and an outlet port, a valve body with a main passage communicating selectively between one of the inlet ports and the outlet port and rotatably supported in the housing to perform the changing-over of inlet passages. Among these inlet ports, an inlet port for purging fluid is opened in the housing, and a shroud-like gap surrounding the valve body is formed between the inner periphery of the housing and the outer periphery of the valve body in such a manner that it communicates with the inlet port for the purging fluid disposed in the housing and is always to be communicated with an opening of an inlet port of the main passage during the changing-over through the rotation of the valve body.