Home | Seal Support Systems | API 682 plan 53B | Mechanical seal system SPB-500

Mechanical seal system SPB-500

A complete and fully functional Plan 53B system for arrangement 3 (3CW-FB, 3CW-BB, 3CW-FF) dual seals in accordance with API 682 or ISO 21049 latest edition – for shaft diameters ≤ 60mm and >60mm. 

These low budget, yet complete and fully functional API 682 compliant units are best suited for standard applications. Appreciating the need for sustainable and robust designs, without compromising performance, system construction primarily uses SS316 tubing and tubing components, except for the accumulator and cooling section.

For the tube fittings Flopac uses double ferrule compression fittings. These fittings are absolutely leak- and gas-tight, resistant to high pressures and temperatures and are known for their reliability.

The accumulator is a commodity item that is usually constructed from Cr/Mo steel using a Nitrile bladder and seals. Other materials available on request.

The highly efficient Flopac forced- or natural air draught seal coolers are constructed from SS316L seamless piping with full contact laser-welded SS316Ti cooling fins. Our range of TEMA C shell & tube seal coolers typically use SS316L piping with a SS316 bundle and CS shell. 

Other materials available on request.

Standard configuration

Design PED 2014/68/EU (CE) – ATEX 2014/34/EU for a Zone 2 II/A T1-T3.
and/or ASME VIII – div. 1 w/o U-stamp.

Suitable for general oil/water service – Non-hazardous, wetted parts AISI 316(L).

Design 40 barg @ -15/+90°C / ANSI 300#-sch.40s.

Seal supply and return connections ¾” NPT
Fill connection 1/2″ NPT c/w quick connector
Remainder 1/2″ NPT.

Engineering units: SI units, Bar/°C.
NDE: Visual-/hydrostatic and leaktesting
Surface preparation: Flopac standard

Including a SS316L/316Ti heat exchanger, Flopac type CNA-100 with a nominal capacity of 750 Watt.
Coolers with higher capacities available at request.

Including one 4-20mA Smart/Hart® pressure indicating transmitter, installed complete with a SS316 instrument block/bleed valve.

Available at request:
Extended NDE packages to include inspections such as X-ray, LPE and P(A)MI.
Refer to the section ‘options’ below.

Available at request:

Extended NDE packages to include inspections such as X-ray, LPE and P(A)MI.

Refer to the section ‘options’ below.

SPB-500 Configuration


Main components


One piping assembly

An all stainless steel 316/316L construction with threaded NPT connections, as appropriate.



The fill-, vent- and drain connections are provided with a valve. The fill connection is additionally fitted with a butt-welded non-return valve to prevent the accidental backflow of potentially hot and dangerous barrier liquid during filling operations. The nitrogen charge connection is a commodity item provided with a gas-valve. Further appendages as appropriate.


One pressure indicating transmitter

A 4-20mA Smart/Hart® pressure transmitter of high industrial quality with a 0.2% accuracy and including a local display. Wetted parts SS316 with an IP 66 PU coated aluminium housing. Mounted on a SS316 instrument block and bleed valve.


One natural air draught cooling secion

A Flopac high efficiency CNA-100 natural air draught cooler, body material SS316L with full contact laser-welded 316Ti cooling fins(*1). Nominal capacity 750 Watt. Higher capacities available on request.

(*1) The full contact laser-welded 316Ti fins offer superior strength and a much better heat conductivity. 316Ti fins are well suited for offshore conditions.



Alternative material selections for specific 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 cannot be used!)

Contact us


Westelijke Havendijk 15

4703 RA Roosendaal

The Netherlands


+31 (0)165 593 170