Welding of pneumatic butterfly valve
Therefore, under the same stroke length, the hydraulically formed pneumatic butterfly valve is much longer than the welded pneumatic butterfly valve. They are enclosed in the bonnet and above the normal valve height (see Figure 9.60). One of the main advantages of the rolling manufacturing structure is that it will not capture the processing materials in the folded layer like the welded pneumatic butterfly valve.
Generally speaking, the service life of the formed pneumatic butterfly valve is longer than that of the welded pneumatic butterfly valve. This is determined by the limited welding, the total strength of the ripple and the limited stroke of each crease (compared with the flat ring welded). In many structures, when the pneumatic butterfly valve is damaged due to mechanical failure, the stuffing box is placed above the pneumatic butterfly valve as a support.
In order to warn the pneumatic butterfly valve of failure, an alarm connector connected to the system shall be installed on the valve cover. Although metal pneumatic butterfly valve seals do not have the ability to resist failure, they can still provide reliable seals to prevent leakage into the atmosphere. According to different working conditions, pneumatic butterfly valves can be made of many different materials. Among them, 300 series stainless steel, Inconel and Hastelloy C have become standard materials due to their stress fatigue resistance and corrosion resistance.
