First pressure-equalizing burst disc for low-pressure liquid containers

Pressure relief and ventilation with a single component: The new "breathing" burst disc eVent simultaneously ensures atmospheric pressure equalization and safe, precise relief at critical pressures.

Many liquids must be kept sterile in hermetically sealed containers during transport and storage and shielded from environmental influences. The COVID-19 pandemic has further increased this need. Bormann & Neupert by BS&B now offers eVent, a pressure-relieving rupture disc that is also permeable to air and thus acts to equalize pressure. The combined component is particularly suitable for low-pressure liquid containers with a design pressure below the standards according to PED and ASME.

"Breathing" rupture disc equalizes several millibars

The new "breathing" rupture disc eVent allows air to pass through and compensates for overpressure or underpressure of several millibars without bursting. This addresses a common challenge in process and plant engineering: even small temperature fluctuations can cause the volume of liquids to change so significantly that problematic pressures develop in fully sealed low-pressure containers. eVent always provides an atmospheric pressure equalization in such cases. Under normal operating conditions, it remains leak- and maintenance-free, just like conventional variants.

Only when the desired activation pressure is reached does eVent precisely respond and open the relief cross-section. All pressure-sensitive system parts are thus reliably protected from damage caused by temperature-induced pressure fluctuations and from "true" critical pressures. This dual function is achieved thanks to a membrane made of sintered polytetrafluoroethylene — short PTFE. The porosity of the material allows air to pass through at a few millibar pressure difference; however, liquids are reliably retained.

A challenge during the development was the need for a safe response at low rupture pressures of around 0.5 bar. The high manufacturing tolerances of the PTFE membrane, due to material properties, are compensated for by combining it with a thermally stable metal component. This controls the burst pressure, while the PTFE seal ensures pressure equalization.

Bormann & Neupert by BS&B supplies the breathable eVent rupture discs as lightweight, integrated, ready-to-install assemblies in nominal sizes from DN25 to DN150 and with a thickness of up to 0.1 millimeters. Thickness and density are tailored to specific applications. Installation is carried out between aseptic connections or conventional pipe flanges.