IS & Ex


Corrosion-resistant flameproof junction box

June 2023 IS & Ex

Pratley has developed and launched a ground-breaking new product, the Flameproof Ex d Envirobox. This is the world’s first polymeric, corrosion-resistant, direct-entry, flameproof junction box. Its recent launch signals a major milestone in the electrical industry and has been described by Pratley electrical research and development manager, Sven Breedt as: “a new product unlike any other in the world and one of Pratley’s most innovative electrical inventions”.

Flameproof equipment is designed to prevent internal ignition within a flammable atmosphere from transmitting outside the protective enclosure. However, all traditional direct-entry flameproof junction boxes made from steel, cast iron or aluminium materials can be prone to corrosion over time and when used in very harsh environments. Special attention needs to be given not just to the overall climatic conditions of the area where the enclosures are installed, but also to the material and design of the equipment.

The new Flameproof Ex d Envirobox junction box, made from a specially formulated, robust engineering polymer, is designed to withstand severe environmental conditions. This makes it ideal for use in areas with a high risk of corrosion, such as offshore oil platforms, underground mines, and petrochemical plants. “The need for a lightweight and corrosion-resistant flameproof junction box is evident with the current, ever-changing mining environment,” says Breedt. “Over a decade’s worth of research and development went into the design and development of this junction box.”

The specially formulated, robust engineering polymer is unique to Pratley. The material has exceptional mechanical properties such as strength, stiffness, creep, dimensional stability, and more. This ensures that the Envirobox can withstand 2 x 20-joule impact tests in a staggering -40°C environment, and has been third-party tested to a massive 4000 kilopascal internal pressure. Additionally, it is IP66/68 certified for continuous underwater depths of up to 300 metres, making it water, dust, and gas protected.

The lid and base have an accurately machined flame path. “The flame path surface of traditional Ex d junction boxes is coated or greased to prevent corrosion. However, this is not a long-term solution as the coating can wear off, and greases would need to be reapplied periodically,” continues Breedt.

The engineering polymer of the Envirobox ensures that the flame path is completely corrosion resistant. The machined surface flame path renders the junction box safe, easy to use and maintenance-friendly in surface and underground mining applications. The lid is fastened down with eight stainless steel A2-70 Allen head screws, contributing to the corrosion resistance of the junction box, and it has Pratley’s signature red Ex identification band for quick Ex equipment identification.

The junction box is supplied standard with 4 x M25 entries but can be supplied with M20 entries or smaller entries on request. The box can accommodate Pratley Ex d flameproof cable glands and accessories. The junction box is therefore exceptionally versatile. Each box is supplied as a standard two-way box with two flameproof blanking plugs.

It can safely accommodate terminals, connectors, relays, and any other non-energy storing devices. The internal bosses are drilled and tapped to provide an earthing point for terminal mounting rails or earth lugs. These are electrically connected to the box entriesm 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. It has an optional external earthing point and is supplied with 4 x M6 Nuts and washers, and a 1 x M6 Spring washer.

The Envirobox is fully certified to SANS, EN and IECEx Standards 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 and 22 and an ambient temperature range of -40 to 55°C.

“The Envirobox is a revolutionary junction box that sets a new standard in the electrical industry. I am confident that what Pratley has produced is a product that not only complies with our policy statement of producing products that outperform all others on the world market, but exceeds that policy. Our goal was to produce the only direct entry junction box that is corrosion resistant, and the launch of the Pratley Flameproof Ex d Envirobox certainly achieves that goal. It is a world first, and I see it marking the future of electrical termination products for explosive atmospheres,” concludes Breedt.

For more information contact Sven Breedt, Pratley, +27 11 955 2190, sales@pratley.co.za, www.pratleyelectrical.com




Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Leading the way in PDS technology
IS & Ex
Booyco Electronics, an original equipment manufacturer specialising in mine safety equipment, has witnessed a surge in demand for its proximity detection systems (PDS) and collision prevention systems (CPS) since the Mine Health and Safety regulation focusing on trackless mobile machinery was promulgated. These systems offer crucial vehicle-to-pedestrian and vehicle-to-vehicle detection capabilities.

Read more...
Ensuring lone worker safety
IS & Ex
The Conextivity Group’s startup – Wearin’ – has developed a solution connecting the lone worker with the control centre. This was commissioned by concrete producer, Pro Beton to ensure the safety of its teams of machine operators and cleaners working on production sites during the day, night, and weekends.

Read more...
Cathodic protection system for hazardous environments
Omniflex Remote Monitoring Specialists IS & Ex
When NSW Ports in Australia embarked on a two-year programme to rehabilitate the structures and combat corrosion levels at its Bulk Liquid Berth 1, it commissioned Melbourne-based consultancy Infracorr to deliver a bespoke cathodic protection) system. To deliver the system safely, Infraccor engaged cathodic protection specialist Omniflex to support the hazardous area and remote monitoring aspects of the CP system design.

Read more...
Safety breakthrough in live testing of large equipment
IS & Ex
While essential to effective maintenance, the live testing of mining vehicles and equipment can be hazardous and time consuming; but this has all changed with the SafeGauge range of digital testing systems. Developed in Australia, SafeGauge is now distributed in South Africa by Booyco Electronics, known for its leading role in promoting safety on mines through its proximity detection systems.

Read more...
Explosion-protected control units
Pepperl+Fuchs IS & Ex
The new range of control units from Pepperl+Fuchs offers a clever solution for switching and controlling circuits in hazardous areas that are designated ATEX/IECEx Zones 1/21 and 2/22.

Read more...
The importance of understanding SIL ratings
Omniflex Remote Monitoring Specialists IS & Ex
Major industrial accidents around the world, like the Bhopal chemical plant disaster, have occurred due to insufficient and poorly designed safety systems. Gary Bradshaw, director of alarm and safety system specialist Omniflex, explains how SIL ratings work and the dangers of the misconceptions that exist around them.

Read more...
The importance of understanding SIL ratings
Omniflex Remote Monitoring Specialists IS & Ex
Major industrial accidents around the world, like the Bhopal chemical plant disaster, have occurred due to insufficient and poorly designed safety systems. Gary Bradshaw, director of alarm and safety system specialist Omniflex, explains how SIL ratings work and the dangers of the misconceptions that exist around them.

Read more...
Mobile workers 4.0
Pepperl+Fuchs IS & Ex
Intrinsically safe smart devices enable lone mobile workers to work seamlessly throughout the plant with the help of digital support. The significant increase in production efficiency and reliability is noticeable.

Read more...
Functional safety over EtherCAT
Eagle Africa Technology IS & Ex
HMS Networks has released a new version of the Ixxat SafeT100 module, allowing users to implement safe I/Os for FSoE (Functional Safety over EtherCAT), which was previously available only for PROFIsafe and CIP Safety.

Read more...
Overcurrent protection for explosion-protected areas
Phoenix Contact IS & Ex
The customisable Caparoc circuit breaker system from Phoenix Contact now also offers modules for explosion-protected areas, thereby extending the range of possible applications.

Read more...