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Marston – Monobloc Graphite Discs

The Marston Monobloc Disc assembly fits directly between plant flanges eliminating the need for a separate holder.

Marston Monobloc discs are recessed on the vent side overcoming the necessity to use special vent side flanges.

Monobloc discs require controlled torque loading of the flange bolts.

All graphite discs fragment upon bursting and are not recommended for relief valve protection.



  • Excellent corrosion resistance
  • Suitable for gas or liquid applications
  • Size range 25-600mm
  • Working burst pressure ratio up to 80%
  • Wide burst pressure range
  • Low burst pressure availability

Reverse Pressure/ Vacuum:

Discs subjected to reverse pressure or vacuum may require the addition of a ‘dial’ or bar support. Vent area will be reduced, contact CMC for further details.

Discs with a burst pressure above 1.7 barg will withstand full vacuum without additional support.

Temperature shields:

Graphite discs are suitable for temperatures ranging from -70°C to 180°C. For higher temperatures the disc can be protected using a Temperature Shield, for use up to 500°C.

Temperature Shields must not be used with reverse pressure / vacuum supports.