Case story


Petrochemical facility



With 356 Barg test pressure and 215 Barg design pressure this spectacular Gimbal Expansion Joint has set a new record at Belman. The record of being the Expansion Joint made for the highest pressure ever at Belman. Until this project beat the record, the record was held by an Expansion Joint tested at 251 Barg and with a design pressure of 145 Barg.


Expansion Joints and high pressure

The featured high pressure Expansion Joint is installed in the petrochemical industry, however we see high pressure Expansion Joints applied in several applications such as conventional power plants, nuclear power plants, chemical plants etc. No matter the application, when Expansion Joints are exposed to high pressure special concerns during the design phase needs to be taken. The hardware on the Expansion Joints such as connection ends (flanges and welding ends), tie rods, hinges and gimbals are often having a higher material thickness. Furthermore, at very high pressure the bellow also needs some special reinforcement.


Ring reinforcement for high pressure

When designing Expansion Joints for high pressure, ring reinforcement is often the solution. By supporting multi-layered Expansion Joint bellows with ring reinforcement, an optimum combination of both pressure integrity and service life is achieved. The purpose of the rings is to reinforce the bellows against internal pressure. By adding moment of inertia to the bellows cross section, this counteracts the bellows ability to blow out or buckle (also called squirm) and enhances its stability and pressure integrity. The rings are usually fabricated from stainless steel or other suitable alloy steel products, which are precisely machined to fit into the root between each of the bellows convolutions. The rings are applied when forming the convolutions of the bellows. The rings can be applied to any type of Expansion Joints and movements (including axial, lateral and angular types and movements).


Special ring reinforced solutions

For Expansion Joints with demanding operating conditions, and therefore a design with bellows of thicker plies, e.g. of duplex stainless steel for additional strength, the ring reinforcement is designed in a special way and supported by tie rods, which are connected to the lugs of the Expansion Joint.


Highly experienced with high pressure

Belman has expertly designed, manufactured and supplied many Expansion Joints for high pressure installations and with many different designs to fit the application of the client. For example: Ring reinforced corner relief Expansion Joints for 145 barg pressure  installed at a nuclear power plant. Another project is an Inline pressure balanced expansion joints for 82 barg pressure installed at a fertilizer manufacturer among many others.