A forced seal circulation unit plan 54 (The Flo-Pac range of FCU units) is a-pressurised piping system with an external reservoir that  contains a clean barrier fluid. The barrier fluid is re-circulated by an external forced circulation pump. It is typically used with pressurised dual (double) seals at a pressure greater than the box pressure. The  barrier fluid provides cooling and lubrication for the inner and outer seal. The higher barrier liquid pressure results in barrier liquid leakage over the seal faces into the process, thus fully containing the product.

Heat is removed by an external heat exchanger. 

This system type is typically applied for the more demanding and critical services that require a high level of integrity and operational reliability. For process lines with multiple pumps in similar duty this system type may also be considered a cost effective (single system) alternative, compared to the multiple plan 53 units required otherwise.

Flo-Pac 53A units are well suited for their application, yet for most pressurised sealing configurations HPS would rather recommend the use of a plan 53B.

Liquid refilling & nitrogen:
<Around every 2 to 6 weeks these units require a barrier liquid refill whilst in operation and pressurised, a potentially hazardous situation. For that purpose HPS developed the Flo-Pac HMS series Mobile make-up units, well suited for safe refill operations. 

<For pressurisation these units require an inert (nitrogen) gas pressurising and conditioning system with all the necessary controls and safeties. For that purpose HPS has developed suitable Nitrogen supply and conditioning systems>

If you have an interest for these units, please browse our range of pre-engineered units or address your questions to sales@hpsbv.nl