Double Disk Assembly

Double Rupture Disk Assembly is a Good Solution for Severe Process Environments.

The ZOOK® Double Rupture Disk Assembly is such a versatile device to guarantee safety even in the harshest of operating conditions. The assembly consists of using a primary and secondary rupture disk installed in a permanent holder made of three separate components—the inlet, mid-flange and outlet. Disks are either forward-acting or reverse-acting type or can even be a combination depending on the application.

Environments containing corrosive, toxic or valuable media are ideal for the double disk assembly. In extremely corrosive and toxic conditions the process-exposed rupture disk could leak in volatile conditions. A pressure gauge acting as a Tell-tale indicator in the mid-flange would indicate the leak, while the secondary rupture disk retains the system leak-free. The primary rupture disk could then be changed out at an opportune time.

Double Disk Assembly

Another common application for a double disk assembly is protecting the primary rupture disk from variable back pressure. This condition can occur when multiple rupture disk assemblies are used that are protecting multiple processes. If one rupture disk assembly bursts, the resulting discharge into the common header could subject the remaining rupture disk assemblies to a transient elevated back pressure condition. Another example would be a flare stack system.

In all cases, the secondary rupture disk withstands the system back pressure, isolating the primary rupture disk. Any change in pressure differential across the primary rupture disk induced by back pressure is eliminated and it will rupture at its marked burst pressure.

The Double Disk Assembly, as a quick opening device, has been used in activating pressure systems and used in many applications in the oil and gas industries. This very fast response is even attainable in large nominal bores.

Benefits of Double Disk Assembly

  • Zero Maintenance

  • Zero Calibration

  • Control of Fugitive Emissions

  • Eliminate Back Pressure

  • Extreme Temperature

  • Quick Opening Device

  • Corrosive Applications

The RA4 rupture disks (bursting disks) are designed to cover the majority of low pressure
rupture disk (bursting disc) applications and are designed to be used in the RAH Pre-Torque holder.


  • Solid metal design
  • Ultra low pressure range
  • Designed for Non-fragmentation
  • Disk designs offer high cycle life (when compared to forward-acting design disks)
  • Standard manufacturing ranges of 0%, -5%, and -10% ensures marked rating on disk tag does not exceed the MAWP of equipment
  • Withstands full vacuum without vacuum support
  • Wide range of standard and exotic materials available
  • Resists product build-up. The smooth convex side of the disk is exposed to the process media
  • Unique alignment pin design ensures proper disk orientation into RAH holder
  • 3-dimensional stainless steel tag permanently engraved with complete disk specifications