This innovative product uses a unique polymer to withstand severe environments
This innovative product uses a unique polymer to withstand severe environments.
Infrastructure on offshore oil platforms, in underground mines or petrochemical plants must often withstand severe environmental conditions, meaning there is a high risk of corrosion. To last in these conditions parts require specifically designed materials.
The Flameproof Ex d Envirobox junction box from Pratley Manufacturing and Engineering is one such part. It received the prestigious ‘Award of Excellence for Technical Innovation’ from the South African Flameproof Association (SAFA) at its 2023 awards evening. “Pratley’s Flameproof Ex d Envirobox junction box is a major milestone for the electrical hazardous areas industry. It is a product unlike any other,” says Eldon Kruger, Pratley Marketing Director.
The junction box
Made from a specially formulated, robust engineering polymer the junction box is designed to withstand severe environmental conditions. It is ideal for use in offshore oil platforms, underground mines or petrochemical plants since these are areas with a high risk of corrosion.
The polymer is unique to Pratley and has exceptional mechanical properties including strength, stiffness, creep, dimensional stability and more, according to the company. This ensures that the junction box can withstand 2 x 20-joule impact tests in a -40°C environment.
Flameproof equipment is designed to ensure that internal ignition within a flammable atmosphere is prevented from transmitting outside the protective enclosure. However, traditional direct-entry flameproof junction boxes made from steel, cast iron or aluminium are likely to corrode over time when used in very harsh environments.
This is not the case with Pratley’s Flameproof Ex d Envirobox since it has been third-party tested to a 4,000-kilopascal internal pressure. Additionally, it is IP66/68 certified for continuous underwater depths of up to 300m, making it water, dust, and gas tight. The lid and base have an accurately machined flamepath.
The junction box can be supplied with either 4 x 20mm or 25mm entries or smaller on request and can accommodate Pratley Ex d flameproof cable glands and accessories. Each box is supplied as a standard two-way box with 2 x flameproof blanking plugs.
The internal bosses are drilled and tapped to provide an earthing point for terminal mounting rails or earth lugs and these are integrated to the box entries providing complete earthing continuity.
Boxes can be fitted with an N35 terminal rail, a Pratley patented cranked rail, an inverted cranked rail, or piggyback rails. Pratley Kwikblok terminals and pre-cut lengths of cable with glands can also be factory fitted to customer requirements.
The box has an optional external earthing point and is supplied with 4 x M6 nuts and washers as well as a 1 x M6 spring washer. It also has threaded mounting M5 holes and is able to accommodate a mounting plate that can be purchased separately if required.
Fully certified
The Flameproof Ex d Envirobox is fully certified to SANS, EN and IECEx Standards, including ATEX for use on surface and underground mining applications (Ex db I/IIB+H2 T6..T5 Mb Gb, Ex tb IIIC T85..T100 Db) in Zone 1, 2, 21 & 22, and an ambient temperature range of -40°C to +55°C.
“Pratley’s goal was to produce the only direct entry junction box that is fully corrosion resistant. Our Flameproof Ex d Envirobox is a world-first product from Pratley,” concludes Eldon.
