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axial pipe coupling

Cast Iron & Ductile Pipe Axial Restraint Couplings by Straub

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.

Overview of Restraint Couplings with Progressive Grip

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.

Comprehensive Straub Coupling Portfolio

Hamilton Kent’s comprehensive coupling portfolio supports a variety of piping materials and challenging environments. For concrete pipe systems, the Straub Concrete Coupling offers a durable, weld-free connection. When working with steel and stainless steel pipelines, our steel and stainless steel restraint couplings ensure secure axial restraint and fast installation. For plastic piping, reliable connections are available with our PVC restraint couplings.

Marine environments require robust solutions like the original marine restraint coupling and the flexible marine couplings.

For repair and maintenance, Hamilton Kent provides repair coupling clamps and flex repair couplings that quickly restore pipeline integrity. When axial restraint is unnecessary, the non-axial restraint coupling offers a flexible, secure alternative. Additionally, the HK test coupling allows for convenient pressure testing and temporary setups.

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


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