Bellows Seal Globe Valve

Fully quality controlled and tested CENTROFLOW Bellows Seal globe valve has superior sealing performance and is more efficient to guarantee the security of pipelines with hazardous media than the ordinary globe valve does. It provide the highest fugitive in use of critical processing, and can be considered as a high-quality product for creating a leak-free project.  Applications:
Hot and cold water systems
Oli Chemical Industry
Non-acidic and non-flammable liquid fluid

Technical Data & Features

Design Standard: BS – 5352 (Reduced Bore)
Testing Method: API – 598 / BS – 5146
Socket Weld End as per ANSI-B16.11
Butt Weld End as per ANSI-B-16.25 with end pups
Screwed End as per ANSI-B-1.20.1 (NPT)
End to End as per manufacturers spec.

Metal bellows seals the moving stem and increases durability of packed stem seal valves.
Two secondary stem seals: a) Backseat in open position; b) Graphite packing.
Easy Machining and resurfacing of the seats,for various purposes.
Short travel distance of the disc(stroke) between the open and closed positions,Bellows seal globe valves are ideal if the valve has to be opened and closed frequently;

Two types of bellows seal globe valves

The metal bellows is the main feature of the bellows ball seal valve. There are two types of bellows :

Formed bellows
Formed bellows is made by rolling a flat sheet into a tube and fusion welding it longitudinally. Thereafter, the tube is mechanically formed into a bellows with round and widely spaced folds.

Welded vane bellows
In this type, thin metal plates in the form of gaskets are welded together. Welding is performed on the inside and outside of the gasket-like plates. The welded vane bellows is folded more times per unit length.

How bellows seal globe valves work

Bellows seal globe valves are compact, control valves that utilize a bellows to seal the stem components. The bellows valve has an internal bellows with the lower end of the stainless steel bellows welded to the stem to prevent system fluid from corroding the stem. The other end is located between the valve body and bonnet to create a permanent seal. This double seal construction eliminates leakage, meaning that even if the bellows ruptures, the stem packing prevents further leakage. The bellows is welded to the stem to ensure consistent efficiency and to prevent stem vibration caused by spool movement.

Advantages of bellows seal globe valves

1. The most outstanding advantage of any bellows seal globe valves is the double seal design (bellows + packing). Therefore, even if the bellows fails, the stem packing prevents any kind of leakage and meets international sealing standards.
2. Minimize the loss of media fluid to ensure safety and environmental protection. This will ultimately improve the safety of the plant where the bellows valve is installed.
3. It can be used as an energy saver as it helps to reduce the energy loss due to leakage.
4. Since leakage is minimized, this avoids frequent maintenance of the valve. Therefore, it leads to a longer valve life.
5. Due to longer service life, operation and maintenance costs are greatly reduced.
6. The robust bellows seal design ensures zero leakage from the valve stem, thus providing a maintenance-free condition.
7. Due to the installation of bellows valves, the discharge of flammable, toxic and hazardous chemicals can be minimized, thus improving the safety of personnel.