MDC’s Externally Pressurized Expansion Joints are designed so fluid pressure acts on the outside bellows element rather than on the inside, as in the conventional expansion joint.

The stabilizing effect of the external pressure increases the bellows capability to absorb long axial movement without squirm, making this type of expansion joint the best solution for many situations involving extensive axial movement.

The construction of MDC’s Externally Pressurized Expansion Joints includes a heavy outer pipe which contains the pressure, serves as a shroud to protect the bellows and also functions as a guide. An internal pipe acts as a liner and maintains fluid flow external to the bellows so that corrosive sediment cannot collect inside the bellows corrugations.

Drain or vent connections can be easily provided to remove any sediment or gas that collects inside the outer pressure shroud.

APPLICATIONS:

• Steam lines
• Steam condensate
• Heating water
• Domestic hot water
• Chilled water
• Other applications requiring large axial movements
• Suitable for direct buried applications

FEATURES AND OPTIONS:

• 4” & 8” movement capacity
• Dual units with 8” or 16” movement capacity
• Anchor bases supplied with dual units
• Anchor bases optional on single units
• Standards size range: 2.00”ID x 12.00”ID
• Special size range: 14.00” to 48.00”ID”
• Ends available: Flanged 150/300, Weld Ends, Grooved ends.
• No maintenance required
• No possibility of bellows squirm, as it works in
extension while the joint is being compressed.

MATERIALS OF CONSTRUCTION:
• Bellows:	T304 SS, 3-ply
• Travelling End:	carbon steel, A-53
• Stationary End:	carbon steel, A-53
• External Shroud:	carbon steel, A-53
• Guide & End Rings:	carbon steel, A-285
• Flanges:	B16.5 carbon steel
• Other + options:	carbon steel
• Special materials available for custom orders