Machine for the centrifugal casting of pipes

Claim 1

A machine for centrifugally casting pipes, said machine comprising a casting shell having an axis of rotation and a rotary jacket coaxial with and fixed to said shell, an annular inner space defined by said jacket and water outlet means in said jacket and in axially spaced relation to said inlet means whereby cooling water can be circulated through said annular space, a first annular fixed part having cooling water supply means associated with said inlet means and a second annular fixed part having water discharge means associated with said outlet means, said annular fixed parts being coaxial with and radially spaced from said jacket, each annular fixed part having an axially inner side and an axially outer side, and a sealing means combined with said inner side of each annular fixed part and said jacket and a sealing means combined with said outer side of each annular fixed part and said jacket, each seal comprising in combination a collar fixed to said jacket, a ring encompassing said collar and movable relative to the corresponding annular fixed part, said ring and said collar having respectively cooperative inner faces and outer faces defining small clearances constituting an annular labyrinth gap between said ring and said collar, means for preventing said ring from rotating relative to the corresponding fixed part, and a flexible sealing ring interposed between and engaging said corresponding fixed part and said ring, said gap being such that in machine operation cooling water in said annular space is forced into said labyrinth gaps of the sealing means and forms hydrodynamic seals, said sealing rings constituting static seals.