BS&B SIGMA™ & SIGMA EXL™

Introduction

The Sigma EXL™ Reverse Buckling Rupture Disk (Bursting Disc) has been developed to provide the highest operating pressure capability available from a Rupture Disk (Bursting Disc) pressure relief device. Sigma EXL™ Rupture Disk (Bursting Disc) technology and the SRB-7RS™ Safety Head combine the accuracy and reliability of Reverse Buckling Disk technology with unique disk and safety head design features that enable the Sigma EXL™ disk to operate to 95% of the Marked Burst Pressure (100% of Minimum Burst Pressure according to CEN ISO 4126-2 standards). The Sigma EXL™ Rupture Disk (Bursting Disc) embraces SafT technology, Structural Apex Forming, the central feature on the disk dome enhancing burst pressure accuracy.
At its burst pressure, the Sigma EXL™ Rupture Disk (Bursting Disc) dome reverses and opens by shearing around a circular score line located near the perimeter of the dome. The score line engages with one or more points on the integral hinge down stream of the disk.
The disk opens around its circular score line with the central petal supported by the hinge, avoiding fragmentation.The Sigma EXL™ Rupture Disk (Bursting Disc) is offered with a simple burst pressure tolerance.
No Manufacturing Design Range needs to be considered for this high Operating Ratio disk (effectively a 'zero' range disk).
The performance of every Sigma EXL™ disk is assured by proof pressure testing each disk to its maximum recommended operating pressure. The Sigma EXL™ Rupture Disk (Bursting Disc) provides the user with the highest Operating Ratio of any Rupture Disk (Bursting Disc) pressure relief device.
For users who wish to obtain the enhanced quality assurance testing of this disk design, and can accept more traditional Reverse Buckling Disk accuracy, the Sigma™ Rupture Disk is offered with a -5% Manufacturing Design Range.

Sigma EXL™ and Sigma™ Disk Features

Reverse Buckling Disk in Sizes 1"-8" (25-200 mm)
High Operating Ratio: 95% of marked burst pressure
High Operating Ratio: 100% of minimum burst pressure (CEN ISO4126-2)
Standard 0% Manufacturing Design Range, optional -5%
Designed for non-fragmentation
Designed for Gas, Liquid, or two-phase flow conditions
Fail Safe: Damage- Safety Ratio <1
Saf™ technology
Vacuum resistant
Smooth process side of disk resists product accumulation
Long service life in pressure cycling or pulsating conditions
US Patent No.5167337 and worldwide patents pending
For installation in BS&B type SRB-7RS™ Pretorqued Safety Head

Sigma EXL™ & Sigma™ Disk Specificaton

Min/Max Pressure Rating at 72ºF (22ºC) PSIG (Bar)

US patent Nos 4,751,938, 5005722 and other international patents pending. Products, specifications and all data in this literature are subject to change without notice. Questions regarding product selection and specifications for specific applications should be directed to BS&B Safety Systems, Inc. or BS&B Safety Systems Ltd. All sales are subject to BS&B Safety Systems, Inc. or BS&B Safety Systems Ltd. standard terms and conditions of sale.