A bellows seal is a specialised type of seal used in valves to prevent fluid or gas from leaking along the valve stem – the part that moves up and down when the valve opens or closes.
How Does It Work?
Inside the valve, there’s a metal bellows – a flexible, accordion-like tube. This bellows is welded to both the valve body and the stem, forming a completely sealed chamber. As the stem moves, the bellows expands and contracts, allowing movement without breaking the seal.
Why Is It Used?
Zero leakage: Ideal for hazardous, toxic, or expensive fluids where even a small leak is unacceptable.
Longer service life: Reduces wear compared to traditional packing seals.
Maintenance-free: No need to frequently adjust or replace the seal.
Common Uses:
Think of it as a high-security seal – designed to maintain complete isolation between what’s inside the valve and the outside world.
