Water-cooled high-temperature slide valve, especially hot blast slide valve

In a water-cooled high-temperature slide valve comprising a housing, a valve plate mounted movably within said housing, annular coolant passages extending from the upper portion of said housing along both peripheral sides thereof to the lower portion of the housing, a coolant return passage being provided within said housing radially outwardly of said annular passages in communication therewith and extending about the peripheral edge of said valve plate at least in the lower portion thereof, the improvement comprising at least one transfer port in the lower portion of each of said annular passages for transferring coolant from said annular passages into said return passage, the axial extent of said return passage being defined by radially extending side wall members spaced axially inwardly of the opposed ends of said housing and the cross-sectional flow area of said return passage, at least in its lower portion extending over an arc of 180.degree., is smaller than the overall cross-sectional flow area of said annular passages whereby settling of suspended matter is inhibited.