Gate valves are of flexible wedge, outside screw-and-yoke and bolted-bonnet construction. The valves conform to api 600iso 10434. Globe valves feature a ball-type disc, outside screw-and-yoke and bolted-bonnet construction. They conform to bs 1873 and also meet the general requirements of api 600, including shell wall thickness and stuffing box dimensions. Check valves are of swing-type and bolted-cover construction. They conform to bs 1868 and also meet the general requirements of api 600, including shell wall thickness.