Rupture disc types

There is no single fixed number, because it depends on how you sort them. We usually look at four axes: material, shape, the direction in which pressure loads the dome and the application. On the material axis the main choice is metal or graphite. On shape you choose between flat, multi-layer and domed designs with X or C scoring. Domed metal discs are either forward acting or reverse acting. Then there are application specific designs such as aseptic discs, extruder discs and discs for tank containers. Vacuum suitable discs, double discs and compact burst plugs complete the picture. A real disc combines a position on each axis, and that combination is what ends up in your specification.

For strongly corrosive media, graphite is usually the first family we look at. Graphite is naturally resistant to many acids, bases and aggressive media without extra coatings. That makes it suitable where stainless steel or other metal discs would degrade quickly. We supply graphite discs from DN25 to DN400, for mounting between ANSI or DIN flanges or in a holder. An optional TFE coating is available as a surface treatment. Metal remains an option too, with Hastelloy and titanium alongside standard 316 stainless steel. The final choice depends on the exact medium, the temperature and the mechanical load. Send us the composition of the medium and we will advise which material fits.

A flat disc is the basic version for general process applications, while a domed disc has a curved membrane. Flat discs, often in a multi-layer construction, suit standard positions with steady conditions. The multi-layer build adds strength and reliability at higher pressures. Domed discs are chosen for large pressure differences or where a controlled bursting action is needed. An X or C scored dome creates a defined opening pattern. Domed metal discs are also where forward and reverse acting designs come in. Both shapes can be supplied in 316 stainless steel, with Hastelloy and titanium as options. Which one fits depends on your pressure profile, medium and installation.

For pharmaceutical, biotech and food processes, aseptic metal rupture discs from STRIKO are the natural choice. They are designed for hygienic, sterile processes. Hygienic discs have highly polished surfaces that support cleaning and CIP procedures. Smooth surfaces leave fewer places for product residue to collect between batches. Holders for these sectors combine hygienic design with reproducible performance. Documentation for validation processes can be supplied with them. Vacuum can be an issue in these plants as well, for example when a vessel cools down after steam cleaning. We take cleaning cycles and possible vacuum into account when we advise on disc and holder.

Reverse acting is often the better choice when the process pressure cycles frequently. Reverse buckling holders offer higher resistance to pressure cycles and a lower risk of fatigue. They also perform better at high temperatures. Forward acting discs are the classic design and are known for high burst pressure accuracy in gas and liquid service. STRIKO builds its forward acting metal discs for high pressure environments. A forward acting disc that runs close to its burst pressure, or that sees heavy cycling, can fatigue sooner. The operating ratio between normal pressure and burst pressure is therefore a key input. We compare both options against your actual pressure profile before we advise.

Not all rupture disc types need a separate holder. Metal discs can be installed directly between flanges in systems with straight pipe sections. Graphite discs can often be clamped between standard ANSI or DIN flanges as well. For pulsating pressure, cyclic loading or positions where process integrity is critical, a holder is the better route. A holder positions the disc correctly, applies a controlled load and seals it under operating pressure. It also makes it easier to integrate burst detection or leak detection ports. We supply forward acting holders, reverse buckling holders and vacuum support holders. The holder is reusable, and only the disc is replaced after it has opened.

A burst plug works on the same basic idea, but in a much more compact form. It is a non-reclosing relief component that is usually mounted with a threaded connection. Inside the plug sits a calibrated bursting element that gives way once the set limit is exceeded. Burst plugs are fitted in lines, extruders, pumps and pressure vessels where installation space is limited. They are gas and liquid tight during normal operation and must always be replaced after activation. Temperature has a strong influence on the effective burst pressure of a plug. STRIKO burst plugs are available in different material combinations, such as stainless steel and special alloys. We supply them as part of our role as exclusive STRIKO agent for the Benelux.

We need a clear picture of the process before we can recommend one of the rupture disc types. Start with the medium and its composition. Add the operating pressure including peaks and the required burst pressure. We also need the temperature, both in normal operation and in the relief scenario. The connection and the available installation space complete the basic set. For a replacement, the existing tag data or specification is a good starting point. With this information we select the family, the material, the holder and optional burst detection. Send your data to sales@dutchvalvevision.com or call +31 (0)70-2210560.