Q: What are the operating characteristics of pneumatic butterfly valves? Answer:? Pneumatic butterfly valve is composed of pneumatic actuator and butterfly valve. The pneumatic butterfly valve uses a round butterfly plate that rotates with the valve stem for opening and closing, so as to realize the starting action. The pneumatic valve is mainly used as a block valve. It can also be designed to have the function of regulating or section valve and regulating. At present, butterfly valves are increasingly used in low-pressure large and medium-sized pipelines. Classification of pneumatic butterfly valve: stainless steel pneumatic butterfly valve, hard seal pneumatic valve

The reliability of metal bellows compensator is composed of design, manufacturing, device and operation management. Reliability should also stop thinking from these aspects. Data selection:
For the material selection of bellows used for heat supply network, in addition to the working medium, working temperature and external environment, the possibility of stress corrosion, the impact of water treatment agent and pipeline cleaning agent on the data, etc. should also be considered, and on this basis, the welding and forming of bellows data, as well as the performance price ratio of the data, should be separated to select the economic and applicable bellows manufacturing data. In general, the data of bellows selection shall meet the following conditions:
(1) High elastic limit, tensile strength and fatigue strength ensure normal operation of bellows.
(2) Good plasticity, convenient for processing and forming of bellows, and sufficient hardness and strength can be obtained through subsequent treatment processes (cold work hardening, heat treatment, etc.).
(3) Good corrosion resistance, meeting the working requirements of bellows in different environments.
(4) Good welding performance, meeting the welding process requirements of bellows in the manufacturing process. For the heat pipe network laid in the trench, when the pipeline where the compensator is located is in a low terrain, the corrugated pipe will be soaked by rainwater or accidental sewage. Therefore, the data with stronger corrosion resistance, such as iron nickel alloy and high nickel alloy, should be considered. Due to the high price of such materials, when manufacturing bellows, it is possible to consider adding a layer of corrosion resistant alloy only on the surface in contact with corrosive media. The fatigue life design can be seen from the failure type and cause analysis of the bellows compensator that the planar stability, circumferential stability and corrosion resistance of the bellows are related to its displacement, i.e. fatigue life. Low fatigue life will lead to the decline of stability and corrosion resistance of metal bellows.