A plug valve comprising a body with a cylindrical or conical cavity to receive a sealing liner and a complementary plug. GLOBE VALVEA pair of vertically disposed, parallel ribs extend inward from the surface of the body cavity along each side of each flow passageway forming between them a dovetail groove which increases in radial depth from adjacent the top of the body port to a level near the bottom thereof. Safety valves The outer surface of the liner has a vertical groove spaced from each side of the flow port therein to form, with such flow port sides, Plug Valves vertical dovetail which are secured between the ribs simply by pressing the liner down into the body cavity. The ports in the plug and liner are rectangular, whereby when conical, the lower portion of the flow passages and ports encompass a greater circumferential angle than do the upper portions. Hence, initial flow when the valve opens is at the lower portion where the dovetail interlock is greatest.

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