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Axial Restraint Couplings for Cast Iron & Ductile Pipe

Straub restraint couplings absorb the axial forces from increasing internal pressure with an innovative mechanical frictional connection comprised of anchoring teeth. As the internal pressure increases, the teeth engage deeper into the pipe surface, creating the restraint connection. Whether for pressure or suction lines, thin or thick-walled pipe, Straub restraint couplings install quickly, safely and economically.

Used for: Pull-out resistant couplings use a grip ring to join all types of ductile and cast iron pipes from ¾” to 28” diameter (27mm to 711mm)

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Product Benefits

  • Works with plain-end pipe connections
  • No welding required, saving time and labor
  • Minimal bolts compared with flanged connections, saving time and labor
  • Universal connection for multiple types of pipe
  • Prevents axial movement of the pipe
  • Quick and easy installation
  • Flexible connection compensates for misalignment and angular deflection
  • Innovative progressive gripping system – the higher the pressure, the tighter the grip
  • Available in sizes up to 28” (711mm) diameter. Larger sizes available upon request.

With more than 50 years of continuous development and improvement, Straub restraint couplings are comprised of premium materials and designed for easy installation, trouble-free service, and a long lifespan. Straub’s progressive grip type coupling effectively increases the sealing grip on the pipe as the pressure inside the pipe increases, creating a robust and reliable connection.

Axial Restraint Simplified Selection Info Sheet
Download (XLS 12KB)