10-METER-LONG
DOUBLE HINGED
EXPANSION JOINT

Belman has designed, manufactured and supplied this large 10-Meter-Long Double Hinged Expansion Joint with a nominal diameter of DN 1900. The Expansion Joint will be installed in the main feed circuit of Northern European oil refinery.

Client requirements
The client required a planned replacement for a Double Hinged Expansion Joint which had reached the end of its service life. The existing Double Hinged Expansion Joint is installed in a critical area of the plant. If just one component in this section fails, the whole unit will be negatively affected, with a worst case scenario of a complete plant shut down. For that reason, it was essential that the replacement Double Hinged Expansion Joint was precisely engineered, design verified, tested and manufactured to ensure that any risk of unexpected failures was eliminated. Furthermore, the new Double Hinged Expansion Joint had to be bought up to date to incorporate the latest standards, design codes and be able to combat the risk of water hammer.

The Belman Solution
With the client’s requests and needs in mind, Belman undertook a comprehensive design, engineering and analysis phase verifying the design of the Double Hinged Expansion Joint. Numerous tests were under taken, including Finite Element Analysis (FEA) of the external hardware supporting the weight of spool pipe on the Double Hinged Expansion Joint as well as FEA of the lifting lugs.
The solution proposed to the client involved an updated Double Hinged Expansion Joint designed for 10 barg. This ensured that the design was sufficiently robust for the operating pressure and provided with the necessary resistance against eventual water hammer. The bellows are designed with inner sleeves in order to provide protection, allowing them to withstand the high flow velocity and corrosive media. This design will ensure that the service life of the Double Hinged Expansion Joint can be extended.
The materials were carefully selected to provide resistance against the media (Brackish water) and the operating environment. Furthermore, a coating system was applied to the flanges and the middle pipe to protect the Double Hinged Expansion Joint – this entailed a Zinc-rich epoxy primer coating with a Polyamide cured epoxy inner coat and a final coat of Aliphatic Polyurethane. The Double Hinged Expansion Joint was the perfect Expansion Joint design to absorb the +/-400 mm lateral movement generated by the piping system in the refinery. Additionally, the Double Hinged Expansion Joint is lateral pre-set and fitted with a position indicator on the hinges for axial movement.

Hinges add stability to the Expansion Joint construction
Hinges provide stability to an Expansion Joint construction unit as well as controlling the movement absorption to the planes the Expansion Joint is designed for. In this case lateral and axial movement. The lateral movements arise from ground settling, and the axial movement from the fluctuations in temperature. The hinges on this Double Hinged Expansion Joint are mainly used to support the weight of the middle pipe in between the bellows, including the media. The Hinges have slotted holes to allow axial movement absorption.

Testing and documentation
The Double Hinged Expansion Joint was pressure tested with a client inspection, with a final inspection taking place also at Belmans facilities. A comprehensive Manufacturing Data Book (MDB) was delivered with the Double Hinged Expansion Joint. This contained the certificates, a declaration of conformity, as build drawings, ITP, welding documentation, inspection certificates, NDT procedures and reports, test reports and design approvals from the selected notified body (NoBo).