Abstract: Method for making a plug valve having a housing molded in place about a pre-formed rotary valvemember. The rotary valve member is molded with the mold parting lines lying in a plane containing the axis of the flow passageway. Around the passageway orifice, the mold parting line is eliminated by use of a core insert which forms a recessed region with an annular mold parting line spaced from the orifice. The housing includes a body portion which surrounds the rotary valve member and an annular lip seal member formed as a homogenous part of the body portion and extending inwardly adjacent the recessed region of the valve member. The inwardly extending portion of the lip seal member has the property of flexing to form a fluid-tight seal when the valve member is in its closed position.

Abstract: A plug or ball valve is disclosed having a housing and plug or ball in the housing for controlling the flow of fluid therethrough. A valve stem extends through the housing for rotation of the plug. The valve stem has a narrow peripheral shoulder which is held tightly against the housing by fluid pressure on the plug to prevent leakage past the seal when the valve is in a partially open position.

Abstract: A valve includes a central valve component with an integral housing molded therearound. During the molding of the housing a seal is held against the valve component by spaced fingers of a tool. After molding is complete and the tool is withdrawn, plastic gripping fingers formed from plastic injected between the fingers of the tool during molding hold the seal againt the valve component and the housing.

Abstract: A valve includes a central valve component with an integral housing molded therearound. During the molding of the housing a seal is held against the valve component by spaced fingers of a tool. After molding is complete and the tool is withdrawn, plastic gripping fingers formed from plastic injected between the fingers of the tool during molding hold the seal against the valve component and the housing.

Abstract: A valve includes a central valve component with an integral housing molded therearound. During the molding of the housing a seal is held against the valve component by spaced fingers of a tool. After molding is complete and the tool is withdrawn, plastic gripping fingers formed from plastic injected between the fingers of the tool during molding hold the seal against the valve component and the housing.

Abstract: A plug valve having a housing molded in place about a pre-formed rotary valve member. The rotary valve member is molded with the mold parting lines lying in a plane containing the axis of the flow passageway. Around the passageway orifice, the mold parting line is eliminated by use of a core insert which forms a recessed region with an annular mold parting line spaced from the orifice. The housing includes a body portion which surrounds the rotary valve member and an annular lip seal member formed as a homogeneous part of the body portion and extending inwardly adjacent the recessed region of the valve member. The inwardly extending portion of the lip seal member has the property of flexing to form a fluid-tight seal when the valve member is in its closed position.