152130 ⎘
Taps or cocks comprising only cut-off apparatus having at least one of the sealing faces shaped as a more or less complete surface of a solid of revolution, the opening and closing movement being predominantly rotary Plug valves;; Details; Special arrangements for separating the sealing faces or for pressing them together for plugs with cylindrical surfaces with the plugs or parts of the plugs mechanically pressing the seals against the housing with rolling action