Replacing ‘Yarway’ Slip Joints with Inline Pressure Balanced Expansion Joints…


Bellows Technology have recently completed the design and manufacture of 2 off 350mm/14” NB Inline Pressure Balanced Expansion Joints to replace existing ‘Yarway’ slip joints in a water main in the East Midlands, UK.

The joints are to be located in a 65 meter long main with design conditions of 14.25 Bar at 140 Degrees C, so the joints are designed to absorb significant and multi-directional movements. In addition, the items have been manufactured in accordance with our approval to manufacture pressure equipment under the European Pressure Equipment Directive (2014/68/EU) Assessment Category III, Conformity Assessment Module ‘H’.

Key project features:

  • 350mm/14” NB terminating with PN25 flange connections
  • 500mm/20” NB ‘balancing bellows’
  • 14.24 Bar design pressure
  • 100% Radiographic inspection of bellows longitudinal butt-welds
  • 100% DPI of all bellows, pipe and flange attachment welds
  • 25 Bar hydrostatic test pressure
  • 2,100mm overall length
  • Movement Specification: 130mm compression, 60mm extension and 10mm lateral displacement

Document package containing:

  • 3.1 material certificates
  • Manufacturing drawing
  • Declaration of Conformity to PED Cat III
  • Certificate of Conformity
  • Pressure Test Certificate
  • NDT test reports

Approved weld procedures and qualifications