Technical Specification
API 682 – Plan 53B
The range of Flopac® SPB seal support systems include plan 53B seal flushing units that are typically used with arrangement 3 contacting wet seals (3CW-FB, 3CW-BB, 3CW-FF).
Plan 53B Description
Purpose
Plan 53B seal support systems provide a barrier fluid to cool and lubricate the in- and outboard seals. The barrier fluid is maintained at a pressure greater than the seal box to eliminate product leakage.
Operation
Plan 53B seal support systems are closed loop systems that provide a pressurised barrier fluid for the inner and outer seal of a pressurized dual seal arrangement. During normal operation, liquid circulation between the closed loop and seal is maintained by an internal pumping ring. The barrier fluid is pressurised by an external gas-loaded bladder type accumulator.
A bladder type accumulator is a standardised reservoir that contains a bladder within. The bladder is charged with an inert gas – usually nitrogen – to a predetermined pressure. Introducing a barrier fluid in excess of that pressure will compress the gas loaded bladder storing barrier liquid at a pressure greater than the process/seal chamber pressure. The greater pressure will reverse the normal leakage where the barrier fluid will leak into the process instead. Thus the product leakage is eliminated entirely.
Maintenance is limited to a timely refill of barrier fluid. Refer to notes/recommendations below.
Heat exchangers
In order to provide cool barrier fluid plan 53B seal support systems are often equipped with a cooler. The cooling capacity must be designed to cope with the seals heat generation and the heat soak. Natural air draught cooling is the preferred method for cooling.
Plan 53B seal support systems are ideally suited to fit natural air draught cooling designs, but our flexible designs will allow for external water coolers or forced air blast coolers just as easy. Flopac can provide all. Please have a look at our cooler section to check our standard availability. Tailored solutions are also available.
Instrumentation
A plan 53B should be equipped with a pressure indicating transmitter to monitor the systems pressure and – applying Boyle’s law – the liquid volume. This will omit the need for a level transmitter and a level gauge bringing considerable savings. A temperature instrument could be considered if relevant.
Notes/recommendations
Flopac provides a complete API 682 compliant package, including all the necessary appendages.
The operating principle of this seal plan accepts a certain leakage of barrier fluid into the process.
Though little (typically 10cc/h and less), the compatibility of the barrier fluid with product must be verified.
The unit operates under pressurised conditions. A safe refill of barrier fluid – under pressurised conditions – requires specific equipment, usually referred to as topping-up / make up or refill units. Please refer to our section Make up units for further details.
For most pressurised applications we would recommend a plan 53B rather than plan 53A or 53C. Easy to operate plan 53B systems need little maintenance and perform highly reliable, while our flexible designs are easily adopted to cope with the most challenging needs. Best suited for natural air draught cooler designs. A Plan 53B would not need a process tap, like the 53C, and, containing the pressurising gas apart from the barrier liquid it eliminates the worry of the gas dissolving in the barrier fluid, like with the 53A.
Independent of the often limited pressure capacities of a plant gas network the 53B can be operated at any desired pressure level.
Please contact Flopac for a more detailed advise on all topics related to Flopac® seal support system plan 53B. We will gladly assist.
Plan 53B Features
Plan 53B – main features
Pressurised by a gas loaded accumulator.
No product leakage.
Lubricates and cools the seals.
Clean barrier fluid film on inboard seal faces improves seal live.
Circulation device needed.
Benefits of the Flopac Plan 53B
Wetted parts all SS316.
Flexible designs all properly engineered.
Reliable performance.
API 682/ISO 21049 compliant.
Compact and lightweight configuration.
Plan 53B Features
Plan 53B – main features
Pressurised by a gas loaded accumulator.
No product leakage.
Lubricates and cools the seals.
Clean barrier fluid film on inboard seal faces improves seal live.
Circulation device needed.
Benefits of the Flopac Plan 53B
Wetted parts all SS316.
Flexible designs all properly engineered.
Reliable performance.
API 682/ISO 21049 compliant.
Compact and lightweight configuration.
Options
Alternative material selections for specific services like HF and H2S (NACE) services.
Flexible designs to fit a specific location or available space.
High pressure designs (ANSI 600# / 1500#) for static designs up to 200 barg.
Additional temperature- or flow instruments to enhance monitoring facilities.
Addition of a barrier liquid circulation unit; to ensure circulation and to enhance cooling capacity.
Addition of an all stainless steel 5 ltr refill unit with 75cc/str handpump. (Other refill options available. Note: filling funnels should not be used!)
Plan 53B Solutions
Contact us
Address
Westelijke Havendijk 15
4703 RA Roosendaal
The Netherlands
Phone
info@flopac.com
