| 摘要 |
<p>A valve (12) 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 (26). The valve seat surface (24) 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.</p> |
