Clamshell Bellows provide a very effective solution when a quick and unplanned replacement of the bellows is needed. Clamshell Bellows are two-pieces expansion joints that are welded together on-site. They can be introduced retrospectively when the existing bellows lose their ability to contain pressure. The purpose of clamshell bellows is to provide a very quick remedial solution with the least disruption to the operation of the pipe system. The use of Clamshell Bellows invariably yields huge cost savings when compared against the cost of the manufacture and ﬁtting of a completely new expansion joint. Clamshell Bellows can be designed as either temporary or permanent solution and as an over-sized or same-sized Clamshell Metal Expansion Joint Bellows.
Design range and scope of supply within Clamshell Bellows
The capability design range for Belman and Clamshell Bellows are:
Up to 150 barg or more if required
-256°C to +1000°C
Austenitic stainless steels, High alloys, Duplex, Titanium, Hastelloy,
Incoloy, Inconel, Alloy 59
EN 13445, EN 13480, EN 14917
ASME VIII, div.I, ASME B31.3
ASME B31.1, EJMA, AD 2000
and others on request
Radiographic examination (X-ray), Helium leak testing, Pressure test, Air test, Dye penetrant test, Magnetic particle examination and many more
Clamshell bellows provide a very effective solution when a quick and unplanned replacement of the bellows is needed. The experienced and certified Belman on-site service team has recently completed a project at a German steel plant. The project involved the installation of clamshell bellows, with two units in size DN 2400 and one DN 2500.
Shell • SABIC • Nyrstar • Hofor • TOR • Saudi Iron & Steel Company • Ineos •
Rosneft • SSI (Corus) • E.On • ThyssenKrupp • ArcelorMittal • ZAK •
Uniper • Salzgitter • Tereos Syral • Vattenfall • Proviron • Essent/RWE •
Kraftwerk Mehrum •
Clamshell Bellows can be used in all types of pipelines and in any industry, but is mainly seen used in:
- Power plants
- Oil refineries
- Steel plants
- Chemical plants
WHAT IS CLAMSHELL BELLOWS?
Clamshell bellows are two-pieces Expansion Joints, that are split in two halfs longitudinally, and then fitted to position and welded together on-site. They are placed on top of the existing Expansion Joint.
TYPES & DESiGNS
Over-sized Clamshell bellows
These are mounted on packing rings and welded to the outer surface of the pipe or pressure vessel on either side of the existing bellows. These rings are sized so that the clamshell bellow is installed over the original bellow. The clamshell bellow is welded to the packing rings and the pressure is ﬁnally sealed by a longitudinal butt-weld joining the bellow convolutions. Provided that the system temperature or any leakage from the original bellows does not constitute a safety hazard, the oversized clamshell bellow can be ﬁtted while the system is still fully operational. This has the critical benefit that no system downtime is required. The original bellows together with any inner sleeves or insulating materials are left in place and are not directly affected by the installation of the clamshell bellow. Fitting an oversize clamshell bellow will inevitably result in an increase in the bellows deﬂection forces with a small increase in the effective area. This aspect has to be considered by the system designer as part of the change-management process and our project engineers will be pleased to provide information in respect of this.
Same-sized Clamshell Bellows
Installation of same-size clamshell bellows requires a shutdown of the pipe system. The existing bellows are
stripped from the pipe system or pressure vessel and replaced by new bellows sized to match and mounted directly onto the original pipe system. The tangents on the bellows are welded to the outer surface of the pipe system, as with an over-sized clamshell and the convolution halves are connected using a longitudinal butt-weld at each joint. Same-size clamshells can usually be designed so that the stiffness and effective area exactly or very closely, match the original bellows. The result is zero or negligible changes to the performance characteristics.
Belman is recognised for our customised solutions and for always helping the client getting the exact Expansion Joint solution optimum for the application and proejct in question.
This animation is showcasing how Clamshell Bellows looks and are installed
What are the advantages of using Clamshell Bellows?
Clamshell bellows provide a very effective solution when a quick and unplanned replacement of the bellows is needed. Clamshell bellows are two-piece expansion joints that are welded together on-site. They can be introduced retrospectively when the existing bellows lose their ability to contain pressure. The purpose of clamshell bellows is to provide a very quick remedial solution with the least disruption to the operation of the pipe system. The use of clamshell bellows invariably yields huge cost savings when compared with the cost of manufacturing and ﬁtting a completely new expansion joint. They can be designed as an over-sized or in the same-size and for either a temporary or permanent solution. We design and manufacture this type of bellows up to DN 12.000 in size, utilising all kinds of materials and in both round and rectangular shapes.
BEFORE & AFTER
Before Clamshell Bellows repair
After Clamshell Bellows repair
QUICK & COST-EFFICIENT
SOLUTION TO REPAIR UNPLANNED LEAKAGES
Installation of Metallic Expansion Joints and in particular clamshell bellows requires skilled and experienced installation professionals. In many instances customers prefer the manufacturer to perform such installation work to minimise the risks from an incorrect installation. In these cases, our on-site service team of skilled and certiﬁed welders expertly assists our customers.
THE ON-SITE SERVICE TEAM
WHEN YOU NEED ASSISTANCE
The Belman on-site can quickly go any site of yours to help on emergency repairs, clamshell installations – they have done it many times before.
The on-site service team members have extensive experience in working on-site worldwide and in various industries. They are certiﬁed for welding according to ASME IX, EN 287 and EN 1418. Furthermore, they are certiﬁed to operate overhead travelling cranes and forklift trucks. The welder certiﬁcates can be forwarded upon request as part of the welding documentation.
Our on-site service team has completed lot of mandatory coursers and own the certificates and necessary approvals. They are also ready to take other relevant coursers according to customer requirements.
The on-site service team members attend courses in first aid, and due to previous project demands, they have attended several additional safety courses, helping them to comply easily with any safety requirements mandated by clients.
FLAME RESISTANT CLOTHING
All clothing worn by the on-site service team makes use of flame retardant/antistatic materials especially designed for the purpose and according to the relevant standards: EN 1149-5, EN 11611, EN 11612 and EN 61482-1.