Pressure-Tested Expansion Joints with Equalising Ring Reinforcement

Reinforced Ring

Belman’s equalising ring reinforced expansion joints are designed to help deal with the challenges presented in environments where exposure to high pressure is required.

The expansion joints were designed, manufactured and tested for a Russian fertiliser producer, while they were part of a larger project, which also included pressure-balanced expansion joints.

Why ring reinforcement?

An optimal combination of both pressure integrity and service life is achieved when a multi-layered expansion joint bellows is supported with ring reinforcement. A 100% pressure test is always performed to verify the ring’s pressurised integrity.

The rings are usually fabricated from round bar or sheet/plate in stainless or suitable alloy steels. These are then precisely machined to suit the convolutions profile.

In order to ensure the dimensional integrity with each convolution, the rings are always controlled via a full visual check.

Equalising rings are solid stainless steel rings, which are externally fitted on the bellows. The rings are precisely machined in order to fit into the root between each of the bellows convolutions. The purpose of the rings is to reinforce the bellows against internal pressure.

By adding moment of inertia to the bellows cross-section, their tendency to blow out or buckle (also called squirm) is counteracted and its stability and pressure integrity is enhanced. Bellows with reinforcing rings can be produced for any type of expansion joint, including axial, lateral or angular.

Experience with ring reinforcement

Belman is highly experienced in the design, manufacture and test of expansion joints with equalising ring reinforcement.

The company has successfully manufactured expansion joints with different dimensions and for several applications.

They are designed for a working pressure of more than 185 barg and one vessel expansion joint was pressure tested at 251 barg.

Belman can deliver expansion joints with ring reinforcement in accordance with EN 13445, EN 14917, and EJMA standards. The firm can also produce joints in line with other standards upon request.

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