Bellows valves are a type of industrial valve that uses a metal bellows as its core sealing element. Their greatest advantage lies in the perfect combination of high strength and zero-leakage sealing, making them widely used in applications with extremely stringent sealing requirements, such as petroleum, chemical, and nuclear power industries.
The Key to Ensuring the Sealing Performance of Bellows Valves
The core of a bellows valve is a tubular structure welded from multiple layers of thin-walled metal (such as 304/316L stainless steel or Hastelloy). One end is welded to the valve stem, and the other end is welded to the valve body or bonnet.
Dynamic Sealing: During valve opening and closing, the bellows moves axially with the valve stem, achieving a frictionless dynamic seal through the elastic deformation of the bellows, effectively avoiding leakage caused by wear in traditional packing seals.
Static Sealing: The welded joints at both ends of the bellows form a permanent seal, completely confining the medium inside the bellows and isolating it from the external environment, thus achieving “zero leakage” (extremely low leakage).
Double Safety: To enhance safety, a stuffing box (such as flexible graphite packing) is typically installed on the outside of the bellows. Even if the bellows fails unexpectedly, the packing acts as an auxiliary seal to prevent external leakage.
Due to its superior sealing and pressure resistance, bellows valves are widely used in the following fields:
- Oil and Gas: Such as wellhead shut-off valves in shale gas extraction to prevent high-pressure natural gas leakage.
- Chemical and Petrochemical: Used to control flammable, explosive, highly toxic, and high-purity media such as hydrogen, ethylene, liquid ammonia, and heat transfer oil.
- Energy and Power: Used as a main steam isolation valve in the secondary loop system of nuclear power plants to prevent leakage of radioactive media; also used in supercritical boiler feedwater systems.
AIV bellows valves feature a conical disc design with a double-sealing structure consisting of bellows and packing. We develop new materials that offer excellent wear resistance and corrosion resistance. Advanced hydraulic simulation software helps us optimize valve flow. Customers benefit from safer operating cycles, higher energy efficiency, and lower operating costs.