Clamshell Type

Dewdon Clamshell bellows is the best solution when a quick and unexpected replacement of the bellow is necessary. Clamshell bellows is a two-piece bellow which is welded around the existing unit. The bellows is split in half longitudinally in our works. The halves are match-marked to ensure the bellows halves are aligned correctly.

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.

Advantages

• In non-critical failures, permits repairs to expansion joints without shutting the plant down.
• Provides temporary expansion joint repair until a scheduled outage.
• In critical failures, enables rapid restart after an emergency shutdown.
• Can facilitate repair when access to the expansion joint is via confined spaces

Operating range

Diameter: Up to 4,250 mm (170”)
Process temperature: Up to 900 °C (1,650 °F)
Pressure: Up to 80 bar (1,200 PSI)

Types of clamshell expansion joints:

• Clamshell expansion joint same-size
• Clamshell expansion joint over-size