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Various Applications of Metal Bellow Seals

by Joanne Henley (2020-07-15)


The bellow seals with technology have various benefits and applications. Metal seals are the elastic vessels which can be compressed while pressure is applied to the outside of the vessel or extended under vacuum. After the pressure or vacuum is released, the bellows go back to their original shape. Metal Bellow Seals are found in space applications like reservoirs with potable water as well as accumulators to collect wastewater.

Using the metal seals various liquids and gases can be measured as well as extreme temperatures too.  Though the bellows seals can eliminate O-rings to increase compatibility, it can even reduce potential leak paths. Known as a high-technology product, these can bear resemblance to the original leather bellows used traditionally in fireplaces and forges.

Types & Applications Of Bellows:

Valve Sealing: These are used between the housing and the rising stem to seal the inside part from the outside world. In Europe, this device is compulsory in order to prohibit any leakage.

Load Cells: A load cell deforms when it is loaded with the form of a pressure or a strain imposed on it. This deformation is detected by a strain gauge through which a low voltage direct current is flowing. The fluctuation in voltage is detected and made visible on a control panel. That is when the bellow seals are mounted over the gauge to protect it from outside influences.

Vacuum Interrupters: The transformers are always huge and the amount of electricity voltage it has is humungous. So, while using for high voltages, the sparks get affected and thus as a precautionary measure oxygen has to be removed in the area where the sparks occur. This is when metal bellow seals is required to seal the spark area completely. Bellows are used to seal such amount of volumes, so that the inside part of the bellow is evacuated or filled with an inert gas as well.

Exhaust Bellows: In railways, automobile industry and many other industries, the engine run constantly and causes self vibration. Thus, to compensate for those movements and temperature differences resulting in thermal expansion, bellows are used to connect the exhaust Gas Purification pipes to the funnel.

Mechanical Seals: Seals are used for closing the inside of a pump from the outside world to prevent leakage. There has to be a sealing element consisting of a stationary and a rotating ring while the pump shaft is turning. These metal bellow seals are mounted on the pump shaft. A spring is also fitted to enforce sufficient pressure on the two rings. This spring have the form of a diaphragm (welded) bellow.

In the mechanical industry, Metal Bellow Seals are regularly used in various industries such actuators, aerospace such as altitude sensors and fluid management devices like accumulators, surge arresters, volume compensators and fluid storage. There are typically found in two types which is formed and welded. These are also used in the medical field like implantable drug pumps.