Bellow sealed valve
Benefits of a Bellow Sealed Valve
A Bellow Sealed Valve is a industrial process valve designed to eliminate valve leakage and are also known as ‘Zero Leak Valve’ or ‘Emission Free Valve.’ In these Valves, conventional gland packing is appended/supplemented by a metallic Bellow Cartridge joined to the valve bonnet at one end, and the stem at the other end. A bellow is a long accordion-like tube. As the valve stem strokes, the bellow expands or compresses with the stroke movement. There are no sliding or rotating seals through which process fluid can pass. The fluid will enter the valve from the seat of the valve & come in contact with the bellow, but will not come in contact with the stem.
The bellow sealed valve is widely used in many severe service applications since the 1950s. It can and should be used wherever external leakage of process fluid impacts people, plant performance, or environment. Examples for typical applications for bellow sealed globe valve are;
- Ethylene
- Phosgene
- Vinyl chloride monomer (VCM)
- Isocyanates (MDI, TDI, HDI,)
- Ammonia (NH3)
- Hydrogen Sulfide (H2S)
- Benzene (C6H6)
- Heat Transfer fluids (hot oil, dowtherm)
- LNG
- Steam
Product range bellow sealed valves
Design features of our bellow sealed valves
- Stuffing box packing as secondary sealing element
- Bellows protected from flow in extended bonnet
- Multiple-wall hydro-formed bellows for up to 50.000 operations
- Extended bonnet for good thermal insulation
- Body-bonnet flange gasket fully confined to prevent gasket flow or blowout
- Guided stem reduces stem and disc vibrations
- Two-piece stem protects bellows against torque stress
- No stem bearings necessary
- Forged or casted bodies with safety margin in wall thickness
- Replaceable disc for low maintenance cost
- Knife edge metal-to-metal hard-faced valve seats for bubble-tight shutoff
