MARK ROWLAND, ENGINEERING MANAGER OF TROLEX, DISCUSSES THE EVOLUTION OF FLAMEPROOF CONNECTORS AND THEIR IMPORTANCE IN HAZARDOUS AREA APPLICATIONS
Exd Flameproof connectors were first developed in the 1970s to answer an urgent requirement to improve maintenance and downtime procedures in the coal-mining industry. However, from these early days, this type of connector soon found a wider market in general heavy industry where it has become established and recognised due to its inherent simplicity and reliability. More recently, technical upgrades have been made to the original design, making the connectors more convenient to use in being easier to assemble and disassemble, and incorporating integral shock protection for even greater operational reliability. These re-designed products have recently received Group 1 ATEX approval, in addition to the existing Group 2 approval for general industry.
Safe Choice for Control or Power Systems
Many thousands of Exd connectors have been successfully employed in oil and gas exploration and process plants with a 30-year proven record of reliability. They are equally suitable for control circuits or power distribution enabling swift replacement or removal of critical plant equipment in hazardous areas with minimum downtime – temporary equipment can also be more rapidly deployed. These Exd connectors give a choice of 3, 4, 8, 10, 26 or 37 contact ways for control circuits and medium power circuits as well as high voltage versions. Made to IP67 protection standards, they are available with a choice of stainless steel or brass housings in two body shell sizes and integral shock protecting fenders.
The simplicity and rugged construction of this type of connector remains unchallenged. The performance and reliability is greater enhanced by the use of a unique design of connection pins and tubes; each individual electrical contact features in excess of 36 individual contact springs. This high density of electrical contact points results in major application benefits; considerably reduced spring pre-tension with a corresponding reduction in the insertion force required; over one million mating cycles without contact fatique ensuring high contact security; contact springs are arranged longitudinally along the axis of insertion, further reducing insertion force; the dramatic reduction in damaging wear and tear imposed by conventional lateral spring contacts gives a guarantee of absolute vibration safety; multi-point contact springs lay along the full length of the contact pins, resulting in the lowest possible contact resistance and a corresponding higher current carrying capacity.
For security purposes, there are up to five coding positions to prevent incorrect or invalid mating, and contact pin numbers are deep engraved on both the mating side and the wiring side of the inserts to ensure quick and accurate identification. Plug inserts are coded red and socket inserts are coded blue to obviate any possible confusion.
Easier and Reliable Mating
Once again, attention to operation-simplicity sees two large accessible screw fasteners to unite the connectors in seconds, eliminating any binding or cross-threading of small and fiddly grub screws. Connections are made easy as contact inserts can be simply removed by releasing a single locking ring inside the body shell. Pins and tubes simply push into the insert and conductors can be soldered or crimped directly to the contact without the need for vulnerable, time consuming secondary connecting devices or the use of messy filling compounds. Equally, disassembly is fast and easy. The complete cover shell can be quickly removed by releasing the two large screws, and there is easy access to a spacious full width termination chamber.
Uncomplicated and extraordinarily strong, the connectors are able to tolerate the hard knocks of day-to-day use in extreme operating conditions. All parts are recoverable and replaceable for maintenance, repair and re-use. Contact inserts are all interchangeable between socket units and plug units and pins and tubes are fully removable during, and after, assembly of the connector.
How control systems company Tyco has used Exd connectors
The high quality Exd TX3700 and TX3701 Exd Connectors from Trolex have been used by a leading provider of safety and control systems, Tyco Fire and Integrated Solutions, for use on its Wellhead Control Modules for offshore use.
Each offshore well consists of multiple bore-holes drilling vertically and horizontally and is equipped with a ‘tree of valves’ to control the well pressure and shutdown an individual well in the case of an emergency. The Wellhead Control module on a rig contains the valves and transmitters linked to each tree assembly for each well which are housed within a sliding drawer unit, dedicated to each well.
The Trolex Exd Connectors have been used to connect the drawer unit to the transmitter and valve circuits and are used to isolate each system in the event of a problem or failure. The drawer unit can then be quickly and easily replaced to ensure that well production downtime is kept to a minimum.
Tyco Fire and Integrated Solutions has been supplying control system technology to the oil and gas industry since the early days of North Sea production. These include pneumatic, hydraulic and electronically automated control and safety shutdown systems for both manned and unmanned offshore installations.
How Exd Connectors are used for other offshore applications
Winch manufacturers who design their products for hazardous area applications in a marine environment have chosen to incorporate the TX3700/3701 Connector with Trolex Engineering’s electrical slip ring units to facilitate speedy removal and reconnection between projects. The Trolex Connector has become the preferred product and the plug and go feature is welcomed by operators working in arduous conditions where downtime is at high cost. Applications include oil well monitoring at subsea or land locations and electrical supply and communications for remotely operated vehicles. As well monitoring equipment, operators explore further afield and deeper in the ocean and the connector’s extreme ambient temperature range and electrical properties ensure that it could operate in such parameters.
For further editorial information contact Laura Bradshaw of Trolex on 0161 483 1435, email: [Email protected]