a) The gap between the bellows and the stem, generally 1 ~ 2 mm. b) The bellows can not bear the torque, the design should ensure that the bellows only stretch and compress. c) bellows valve in the open or closed state, the bellows were in compression and tension. d) Bellows shall have the minimum thickness required to withstand pressure and require testing. e) pay attention to the compatibility of materials, practice proved that the inconel alloy bellows high temperature high pressure better material. f) The quality of the corrugated pipe welding process should be assessed and welding records. g) The bellows valve for throttling should consider the effect of flow rate on the bellows. h) Bellows has a certain stiffness, should consider the bellows stretching or compression caused by the increase in operating torque.