Plug valve

A plug-type valve having slips wherein the valve is opened by moving the plug vertically to retract the slips, rotating the plug to align a flow passage with an inlet and an outlet and wherein the plug is again moved vertically to seat the plug against the interior surface of the valve body, the valve comprising:

• a valve body having an interior surface in the shape of a truncated cone;
• said slips having conical surfaces which are substantially congruent to said valve body interior surface;
• said plug having surfaces adjacent said flow passage in the shape of a second truncated cone, said second truncated cone being substantially similar to but smaller than said first truncated cone;
• whereby said vertical motion of said plug both before and after said rotation of said plug is in the same direction.

A plug-type valve having a rotatable plug having a flow passage and connected to a pair of slips and comprising:

• means for moving said plug vertically for retracting said slips for opening said valve;
• means for rotating said plug for aligning said flow passage in the flow path of said valve;
• and
• means for moving said plug vertically for seating said plug in the open position;
• said vertical movement produced by said means for retracting and said vertical movement produced by said means for seating, being unidirectional.

A plug valve of the type having a rotatable plug, a pair of slips connected to the plug for rotation with the plug, a flow passage through the plug, and a valve body having an inlet and an outlet for connecting the valve to upstream and downstream pipes;

• the valve comprising:
• a valve body having a conically shaped interior surface for housing said plug and slips;
• said slips each having an outer facing conical surface substantially congruent to said valve body interior surface and having a substantially planar inner facing surface adapted for slideable engagement with said plug;
• said plug having slip interface surfaces canted to retract said slips from said valve body interior surface upon vertical motion of said plug;
• said plug having conical surfaces adjacent said flow passage, said conical surfaces being parallel to the conical interior surface of said valve body;
• said valve being opened and closed by a sequence of vertical, rotational and vertical motions, the vertical motions for opening said valve being unidirectional and the vertical motions for closing said valve being unidirectional.