The SKR-U™ rupture disk (bursting disc) is partnered with the UR-2 safety head to provide high integrity reverse buckling rupture disk (bursting disc) technology in a threaded union type holder. The SKR-U™ rupture disk (bursting disc) uses Saf™ technology (structural apex forming) to accurately control its burst pressure making it insensitive to the assembly torque variations that will occur in a threaded type holder.
The UR-2 safety head is available in three standard nominal sizes: 1/2 ” / 15mm,3/4_” / 20mm, and 1″ / 25mm. Standard inlet & outlet female threads are 1/2 “, 3/4 “, and 1” NPT. Custom thread configurations are available. The SKR-U™ rupture disks (bursting discs) are identified SKR-U™1/2” / 15mm, SKR-U™3/4″ / 20mm, SKR-U™ 1″ / 25mm and are all supplied with permanently attached 3-D metal identification tags.
Safety Head Design – Rupture Disk (Bursting Disc) Installation
The UR-2 safety head contains 4 metal components: inlet, holdown ring, outlet, and hexagon assembly nut. The SKR-U™ rupture disk (bursting disc) is pre-assembled to the safety head between the inlet and the holdown ring using two capscrews. This locates and centers the disk, ensuring the correct direction of installation: these two capscrews and a single locating pin in the UR-2 inlet have an asymmetric layout that matches three holes in the SKR-U™ disk flange.
This pre-assembly feature ensures that the disk can be easily installed even where the piping flow path may not be ‘vertical up’. The inlet/disk/holdown subassembly is fixed to the UR-2 threaded outlet by a hexagon nut. It is the hexagon nut that provides the sealing load to the safety head assembly (the capscrews are for preassembly only).
As an option, the UR-2 safety head can be provided with a threaded connection on the outlet side to enable the connection of a ‘tell-tale’ assembly.
Torque Drive Adapter
Accurate torque control on a large hexagon can be difficult. BS&B Safety Systems can provide a Torque Drive Adapter for use with all UR-2 safety heads (one adapter for all sizes). This adapter permits the use of a standard torque wrench for control of installation load.
The SKR-U™ safety head incorporates a ‘bite-type’ seal. This concentrates the holder assembly load to cut an impression in the SKR-U™ rupture disk (bursting disc) flange that ensures a leak tight installation.