| 摘要 |
A valve for controlling the flow of a gas therethrough which requires no machining in order to attain an effective seal between the valve seating surface and a rotatable plug element. The valve seat surface remains as cast while the plug consists of an overmolded plastic. The overmolding defines an array of pliable sealing ridges. The use of overmolding facilitates the use of cost-saving plastic materials, and obviates the need for expensive machining of the cooperating surfaces. |
