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SURE-SAF System

The Fail Safe CSI™ Reverse Buckling Disk and CSR-7RS Safety Head

The Sure-Saf® System has been developed to provide optimal safety using rupture disk (bursting disc) pressure relief technology. The CSI™ rupture disk (bursting disc) combined with the CSR-7RS™ safety head provides accuracy and reliability. This unique partnership ensures the CSI™ disk bursts at or below its certified burst pressure in the event that the disk is installed in the wrong direction or becomes damaged.

The CSI™ rupture disk (bursting disc) uses SafT technology (structural apex forming), the central feature on the disk dome, which enhances accuracy of burst pressure. At its burst pressure, the CSI™ rupture disk (bursting disc) dome reverses and opens by shearing around a circular score line located at the perimeter of the dome. The CSR-7RS™ safety head outlet contains an energy-absorbing hinge that aligns with an unscored portion of the CSI™ disk perimeter that retains the CSI™ disk upon opening, avoiding fragmentation.

CSI™ Disk Features

  • Reverse Buckling Disk in Sizes 1" / 25mm ~ 8" / 200mm
  • Non-Fragmentation Design
  • Designed for Gas, Liquid, or 2-phase Flow Conditions
  • Fail Safe: Reversal Safety Ratio <1
  • Fail Safe: Damage Safety Ratio <1
  • High Operating Ratio: 90% of Marked Burst Pressure
  • High Operating Ratio: 95% of Minimum Burst Pressure (ISO & European Codes)
  • SafT Technology
  • Vacuum Resistant
  • Resists Product Accumulation
  • Static or Cyclic Operating Conditions
  • Standard 0% Manufacturing Design Range
  • Optional -5% & -10% Manufacturing Design Range

Reversal Safety Ratio < 1

Should the CSI™ rupture disk (bursting disc) in its CSR-7RS™ safety head be accidentally installed the wrong way, it will burst at or typically below its burst pressure. This "fail-safe" design feature is called the reversal safety ratio. With a value of 1 or less, the CSI™ disk will relieve pressure at a reduced burst pressure should improper installation cause pressure to be applied to the disk's concave side.

Installed in the wrong direction, the CSI™ rupture disk (bursting disc) interacts along its circular score line with stress raising features in the CSR-7RS™ safety head to open at a reduced burst pressure.

Damage Safety Ratio <1

If the CSR™ rupture disk (bursting disc) is accidentally damaged, it will relieve pressure by bursting at or typically below its marked burst pressure. This "fail-safe" design feature is called the damage safety ratio. With a value of 1 or less, the CSI™ disk will relieve pressure at a reduced burst pressure if damaged. When the domed structure of the CSI™ rupture disk (bursting disc) is damaged, it will reverse at a reduced pressure and interact along its circular score line with stress raising features in the CSR-7RS™ safety head to open at a reduced burst pressure.

CSR-7RS™ Safety Head

  • Asymmetric locating pins center the disk in the safety head eliminating disk slippage and ensuring correct installation.
  • The CSR-7RS™ can be pretorqued in the workshop for exact calibration permitting simple and correct installation.
  • For further installation assurance, a J-bolt is fitted which mates with a hole drilled in the inlet companion flange.
  • The CSR-7RS™ fits multiple international flanges ratings including ANSI, DIN, BS and JIS, thus reducing unwanted inventory.
  • Metal to metal bite-type seal 2 inches and above.
  • Unique stress raising features in the bore of the CSR-7RS™ interact with the CSI™ disk circular score line to provide a Reversal Safety Ratio & Damage Safety Ratio of 1 or less.
  • Materials available: 316SS, Carbon Steel, Inconel Alloy 600, Monel Alloy 400 and Hastelloy-C276/Alloy C-276.