Valve bellows are the specialized expansion joints that have the characteristic of leakage-free performance; which is why they are also called as “Zero-Leak Valves” or “Emission Free Valves”.
The outer covering of a valve is called a valve bonnet and the internal part is known as valve stalk or valve stem. The bellow cartridge is connected to both, the valve bonnet and the valve stalk. The convolution present in the bellow cartridge allows it to compress and decompress depending on the movement or spring rate of the valve stem. Simplifying, the bellow cartridge shows compression when the valve is in open state and shows decompression when in the closed state. There are a couple of ways to seal the valve bellow to the valves. Thus, it is also important to install the valve bellows in the valves in a proper manner.
The seal of the valve is an important part of the valve as it forms the heart of the bellow cartridge. The bellow valves must be modified so that they have a valve stem with linear movement only. The linear movement is specific for the bellow valves as it is essential to avoid any twisting of the bellows. This modification is achieved by the use of a cover-nut which will efficiently transport torsion of the hand wheel into a straight movement at the valve stalk, and this is how the seal does not interact with the stem at all. The stem is the functioning part of the valve and, hence, the source of leakage too. The outer protection of the valve by the bellow creates a leak-free zone against the depreciation of the gland packing.
With all of these characteristics, it is important to produce a well working bellow valve with proper flexibility. Pliant bellows is a valve bellows manufacturer and global exporter of the products and we are known for our quality service. We produce elastic metal bellows with high durability following the correct bellow manufacturing process. The valve bellows are hydroformed and are produced by the stainless steel bellow forming machine. Implementing the hydroforming process allows in manufacturing bellows of absolute calibre in comparison with other methods like diaphragm welded bellows or mechanically drawn bellows.
Pliant Bellows is experienced in the field of manufacturing metal bellow expansion joints in India for over 40 years. The valve bellows or the bellow cartridges are hydroformed with accuracy and with known, approved procedure. The designs are precise and have the ability to render its full capacity. We have earned our name among the universal expansion joints suppliers and we are spread out throughout the country and are one of the best metal bellow manufacturers in India.