钢制截止阀 法兰和对焊端 螺栓连接阀盖

This API standard specifies the requirements for a heavy-duty series of bolted bonnet steel globe valves for petroleum refinery and related applications where corrosion, erosion and other service conditions would indicate a need for heavy wall sections and large stem diameters. This standard sets forth the requirements for the following globe valve features: ? bolted bonnet, ? outside screw and yoke, ? rotating rising stems, and nonrotating rising stems, ? rising handwheels and nonrising handwheels, ? conventional, y-pattern, right-angle, ? stop-check (nonreturn type globe valves in which the disc may be positioned against the seat by action of the stem, but is free to rise as a check valve due to flow from under the disc, when the stem is in a full or partially open position), ? plug, narrow, conical, ball, or guided disc, ? metallic seating surfaces, ? flanged or butt-welding ends. It covers valves of the nominal pipe sizes NPS: ? 2, 21/2, 3, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24; corr