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Mechanical seal system SPA-528

A complete and fully packaged Plan 52 system for arrangement 2 (2CW-CW) dual seals in accordance with API 682 or ISO 21049 latest edition – for shaft diameters > 60mm.

For applications with a shaft diameter ≤ 60mm, kindly refer to our SPA-526 units.

Our SPA-528 units serve the need for a more robust and all welded, yet flexible design that easily adopts to the more specific design requirements and/or high end client specs.

Standard configuration

Design ASME VIII, div. 1/not stamped and/or the European legislation (CE) such as PED 2014/68/EU and the ATEX 2014/34/EU – Zone 2 II/A T1-T3.

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

Design 40 barg @ -15/+90°C
ANSI 300# – NPS 6” – sch.40s.
Vmin 20 L @ NLL.

Seal supply and return connections ¾” NPT
All further connections ½” NPT
Coolwater connections OD ½”

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


Available at request:


Designs tailored to meet your specific requirements.


High pressure designs (ANSI 600# / 1500#) for static designs up to 200 barg.


High temperature designs.


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


Refer to the section ‘options’ below.

SPA-528 Configuration


Main components


One piping assembly

An all welded  – stainless steel 316L construction with threaded NPT, socket- or butt-welded flanged connections, as appropriate.



The vent, fill and drain connections are provided with a block valve. The fill connection is additionally fitted with provided with a non-return valve, the vent connection with a 3.2mm bore SS 316 restriction orifice. Further appendages as appropriate;

One pressure indicating transmitter

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

One level transmitter

A 4-20mA Smart/Hart® Guided Wave Radar (GWR) transmitter of high industrial quality with a 0.5% accuracy, excluding local display. Wetted parts SS316 with an IP 66 PU coated aluminium housing.

One level indicator

A Flopac weld pad level gauge with reflex glass complete with level markings. Wetted parts SS316.


One internal cooling coil

A Flopac high efficiency spiral wound cooling coil fitted inside the reservoir. Nominal capacity 1500 Watt. Wetted parts SS316. Connections OD ½” – tube.



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 buffer 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!) 

Contact us


Westelijke Havendijk 15

4703 RA Roosendaal

The Netherlands


+31 (0)165 593 170