| An expansion joint is a device that contains one | | | | stabilized in almost any situation. |
| or more bellows, which is used to assist with | | | | The metal bellows is a cylindrical container or |
| structural changes, such as those produced by | | | | vessel that can be stretched or compressed on |
| the thermal expansion or tightening of a pipe, | | | | account of several circular folds. They are flexible |
| tube, or vessel. | | | | and durable when they are properly used, |
| An expansion joint can be used to allow | | | | meaning if they are used within the designed |
| movement in a pipeline system. The bellows is a | | | | specifications. |
| flexible part of an expansion joint that normally | | | | Metal bellows are used in many different industries |
| consists of several folds. The expansion joint is | | | | mainly because they can perform many |
| the best solution when making a piping system | | | | distinctive functions from sealing environments to |
| more elastic. Flexibility is needed when there are | | | | carrying gases, liquids and slurry. They have the |
| different movements in a pipeline such as, | | | | following standard dimensions: inside/outside |
| frequent vibrations, pulsations and thermal growth. | | | | diameter, free length and spring rate (the spring |
| There are three basic types of movement that | | | | force applied by the bellows). |
| can be applied to the bellows and these are: axial, | | | | There are four different ways to manufacture a |
| a movement in a direction parallel to the | | | | metal bellows. The first of them is electroforming, |
| longitudinal axis; lateral, a movement perpendicular | | | | which actually means to deposit several layers of |
| to the longitudinal axis; and angular, a rotational | | | | metal on a mandrel of aluminum. Secondly, |
| movement of the longitudinal axis. | | | | chemical deposition is very similar to |
| Metal expansion joints are widely used in pipeline | | | | electroforming done by electro-depositing different |
| systems. They are vital elements for these | | | | types of metal on a mandrel; mechanical forming, |
| technologies. The main reason why these flexible | | | | and the forth one is welding. |
| expansion joints are used is because they | | | | The common materials used in the construction |
| compensate different variations that may appear | | | | of metal bellows are usually aluminum, stainless |
| in length. Changes in a pipeline's length are usually | | | | steel, tantalum, titanium or steel. However, the |
| the result of high temperature differences, which | | | | most common available on the market is the |
| the metal joints are designed to withstand. They | | | | stainless steel expansion joint, which can be |
| are designed with consideration for different | | | | manufactured with both single and multi-walled |
| factors, such as: temperature, pressure | | | | bellows. These can be used in different |
| movement and environment. | | | | applications such as turbine piping, engine |
| Metal expansion joints are also required when it | | | | exhausts, shaft propellers and many others. Metal |
| comes to absorbing different vibrations produced | | | | expansion joints have been effectively used in a |
| by motors, compressors or turbines; the various | | | | wide variety of situations since around the year |
| axial, angular and lateral movements can be easily | | | | 1940. |