Butterfly plate shaft is at an angle to improve the sealing. It will be great help if any one could explain how it is achieved?

I am working in a valve factory. I have a question about the dimension for ball valve bore. The description of the valve is given as follow.

MESC for butterfly valves.There's a lot of Shell designation numbers and documents that undergo this acronym.

Sum-up standards applicable for butterfly valves (design, face-to-face, testing,etc..)? Is there any comparison between American and DIN standards?

Vendor leads/information for butterfly valves with a system design of 2300F at 5 PSIG and operating at 1600F at 3 PSIG?

butterfly Valve,But the diameter of the valve should be 180mm.The valve is used to control the flow.

Cast Iron butterfly valves (4"-84") on a SS316L piping. In order to avoid galvanic corrosion I have specified all valves to be rubber lined on interior surfaces and flange faces with Neoprene to a thi

36" soft seated butterfly valves. When the valves were disigned for vent gas compressor suction valves the styrene content was not taken into consideration so the TFE seat ring with viton o-ring are n