The back pressure device SDV prevents the static pressure in the upstream piping system to fall below a defined minimum value – irrespective of the flow rate.
That means the specified minimum pressure is maintained, from the nominal flow rate to zero flow. Back pressure devices are mainly used to avoid cavitation and partial evaporation in the fluid. By increasing the pressure level, they prevent the static pressure to fall below the local vapor pressure. The SDV has an integrated non-return function, i.e. the system is also protected against reverse flow. Size and pressure rating of the SDV are usually guided by the bypass of the AR Valve. It is available in all standard materials, sizes and pressure classes and suitable for all fluids that apply also to the AR Valve.
- no evaporation and cavitation for smooth operation
- definition of a back-pressure in the bypass line