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Ductile Iron Pipes - Socket & Spigot Flexible Push-on Joints

  • Socket and Spigot Flexible Joints are assembled with synthetic EPDM (Ethylene Propylene Diene Monomer) / SBR (Styrene Butadiene Rubber) rubber gaskets of special shape - the gasket has a hard 'Heel' and a soft 'Bulb'.
  • In Push-on joints, the soft bulb of the rubber gasket is compressed when the spigot is inserted into the socket.
  • The 'heel' locks the position of the gasket and does not allow the gasket to get displaced when the spigot is pushed in.
  • The joint becomes tighter with the increase in internal pressure of water. The rubber is confined in a place and cannot blow out.

Permissible Deflection at Socket and Spigot Joints

Where it is necessary to deflect the pipeline from a straight line, either in the vertical or horizontal plane, deflection at the joint should not exceed the following:

Push on Joint Maximum Deflection Angle
80-150 mm
200-300 mm
300-600mm
700-800mm
900-1000mm