Overview
A clamshell bellows is a split metallic bellows assembly designed to be installed around an existing expansion joint, without disconnecting, cutting, or moving the surrounding piping. The bellows assembly is manufactured in two longitudinal halves and is a customizable solution depending on the situation.
Clamshell bellows are used as an emergency or maintenance repair solution when the removal and replacement of an existing expansion joint is impractical, time-consuming, or expensive. In many operating facilities, expansion joints are located in areas with limited accessibility, surrounded by permanent piping, structural steel, refractory systems, or insulation. A clamshell allows installation around the existing bellows without disturbing adjacent components, restoring system integrity while minimizing downtime and labor.
Features
- Customizable repair solution
- Either Installs around the existing bellows without pipe disconnection or system disassembly
- Replace existing bellows with a same-sized solution
- Available for single-ply metallic bellows only
- Custom-designed for application-specific material, geometry, and service conditions
- Oversized configurations are available where access is limited, using rings to increase the enclosure diameter
- Field installation or in-house shop repair options to suit turnaround logistics
- ASME Section VIII engineering, inspection, pressure testing, and stamping are available
Technical Information
85″ Dia. Clamshell Spools Designed for an Exhaust Wall Protrusion Clamshell at a Gas Turbine Facility
Clamshell Bellows Replacement for a Heat Exchanger Expansion Joint
Custom Design Clamshell Pipe Spool for an Exhaust Duct Application in Texas
Three-day Emergency Fabrication of a 40″ I.D., Clamshell Expansion Joint for a Chemical Plant in Texas
FAQs
Is a clamshell bellows a permanent repair?
A clamshell bellows is a temporary repair that restores system containment and allows continued operation while a permanent replacement expansion joint is planned. US Bellows will advise on installation concerns and the appropriate timeline for follow-up permanent replacement for each application.
Can a clamshell be used on any type of expansion joint?
Clamshell assemblies are available for single-ply metallic bellows only. They are not applicable to fabric or rubber, and can not be made into multi-ply metallic bellows. Contact our engineering team if you are unsure whether your existing joint qualifies or discuss available options.
Does the system need to be taken offline for installation?
In many cases, the system can continue operating at reduced conditions during installation. The precise requirements depend on the application. US Bellows offers 24/7 emergency field services and can work with your team to plan installation within your operational constraints.
What information is needed to design a clamshell?
To begin the design, we typically need: nominal pipe size and bellows outside diameter, material and ply count of the existing bellows, design pressure and temperature, type of movement accommodated (axial, lateral, angular), media and any accessibility constraints around the joint. Drawings or dimensional sketches of the existing assembly are helpful when available.
Case Studies
Clamshell Bellows for a Shell and Tube Heat Exchange
Clamshell Bellows Replacement for a Heat Exchanger Expansion Joint
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