| 摘要 |
An aluminum valve which has a seat (43) of stainless steel. This seat is provided by friction welding stainless steel onto aluminium (44) and then shaping the composite to size. The stainless steel can be covered with stellite. The valve is closed by abutment of a PTFE bush (37) onto the seats. The seat can comprise a slope so that any contaminatory material tends to be forced off the seat by the bush in use. |
