Pumps with double seal and plan 53

Belli Meccanica designes and produces Atex pumps with advanced seal systems like double seal pressurized plan 53.

Plan 53 is suitable for more demanding conditions, like MDI and resins applications, using a barrier fluid at higher pressure than the process fluid
The system is made up of two back to back mechanicla seals, an inox barrel, sensors and gauges for pressure and auxiliary liquid monitoring. The external reservoir provides a pressurised barrier fluid for the inner and outer seal of a pressurized dual seal arrangement. The barrier fluid is pressurised by introducing an inert gas (usually nitrogen) from an external source. A regulator is normally used to maintain a constant pressure that is greater than the process/seal chamber pressure (usually at least 1bar). This means that the normal leakage is reversed as the barrier fluid will leak into the process instead, and product leakage is eliminated entirely. Maintenance is limited to a timely refill of barrier fluid, while ensuring a constant and sufficient supply of nitrogen