Therm-Line™ Expansion Joints
All Steel Series 389

The Therm-Line all steel expansion joint by Tuf-Lok™ International has special design features to minimize pressure drop and buildup as a result of excessive leading edges, as it compensates for temperature expansion.

The smooth internal bore allows liquids, solids, liquid with solids or slurries to flow smoothly and easily through the expansion joint without obstruction. In addition, the Therm-Line expansion joint has a low coefficient of friction, resulting in low pressure drops and reduced energy losses.

Therm-Line expansion joints are available in all mild steel or stainless steel construction in 2 inch through 10 inch pipe sizes with a pressure rating of 150 PSIG. The Series 389 Model 15 expansion joint withstands temperatures up to 400° F (204° C) using standard fluoroelastomer seals. For higher temperature applications up to 650° F (343° C), the Series 389 Model 8 is available in a high temperature packing gland design.


  • All steel construction
  • Low pressure drop
  • Handles liquids, solids and liquids with solids
  • Smooth internal bore
  • Temperatures up to 650° F (343° C)
  • Reduced energy losses
  • Rugged construction

Therm-Line Expansion Joint - Coupling Style
Therm-Line Expansion Joint - Flange Style

    Therm-Line Expansion Joints       
    Series 389  

    Dimensions and Specifications

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