Belman has engineered, produced and supplied two specially constructed inline pressure-balanced expansion joints for a Swedish steel plant facility. One of the expansion joints was specially designed with one of the bellows being partly hidden within the balance chamber.
The choice of inline pressure-balanced expansion joints was due to the challenging piping layout, which prevented the use of standard hinged expansion joints.
The DN 1200 inline pressure-balanced expansion joint, weighing 3t, represented a standard solution and was later installed against the silencer. In contrast, the DN 1000, weighing in at 2t, was installed against the compressor nozzle where the available space was limited. This space limitation in the pipe system resulted in a limited gap in the pipeline for the DN 1000 pressure-balanced expansion joint.
Further, the client had a requested spring rate, which the expansion joint had to meet. In order to comply with the client’s wishes, Belman designed a customer-specific special solution.
The special design of the DN 1000
The special design concerned an inline pressure-balanced expansion joint with one of the bellows partly hidden within the balance chamber. This was a natural choice in order to ensure the best absorption of movements, while meeting the required spring rates and built-in length.
Typically, all of the bellows of an inline pressure-balanced expansion joint would be fully visible. The selection of this partly hidden bellow was the result of a more complex calculation of the pressure bearing parts and a requirement for a well-planned line through production.
Additional three expansion joints supplied
Two further DN 1000 hinged expansion joints were supplied to the same steel plant and installed in the pipeline after the DN 1000 inline pressure-balanced expansion joint. There was sufficient space in these locations and the pipeline layout permitted the installation of hinged expansion joints. One of the DN 2200 expansion joints was supplied with customised transport devices, including a lifting device, and installed against the compressor.
The specially designed inline pressure-balanced expansion joints have the following design parameters:
Dimension: DN 1000 • Length: 1729 mm • Medium: Air • Design temperature: -40/260°C • Design pressure: 6 barG • AX: +/-10 mm • LA: +/-3 mm • Bellows: 1.4541 • Pipe ends: 1.0565 • Flanges: 1.0565
Dimension: DN 1200 • Length: 1945 mm • Medium: Air • Design temperature: -40/260°C • Design pressure: 4,4 barG • AX: +10/-40 mm • LA: +/-38 mm • Bellows: 1.4541 • Pipe ends: 1.0565 • Flanges: 1.0565
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