Hawke places confidence in 'Multilam' technology for hazardous area connectors
10 November 2006
Electrical infrastructures in the petrochemical industry and other business sectors where potentially explosive environments may occur, depend on high quality, reliable equipment to ensure the safe operation of plant and equipment. As a means of achieving confidence in the EU, manufacturers of hazardous area equipment submit their equipment for third party testing and certification in line with the ATEX directive 94/9/EC applicable in the EU.
When Hawke International introduced its ControlEx range of connectors certified for use in explosive environments, the many benefits offered by the product range allowed owners and operators of offshore drilling equipment to significantly reduce the wiring installation work that had to be performed offshore. This won great approval in the marketplace, since offshore work tends to be slower and more challenging, and labour rates are relatively high. Hawke International’s ControlEx connectors allowed the majority of the electrical control infrastructure to be completed before the rig was moved into position, reducing offshore work to a simple process of mating the connectors when in situ. Further features of ControlEx connectors, including special mating threads, are also designed to ensure rapid, error-free mating.
Following the success of the ControlEx connector range, Hawke recently extended its offering to the petrochemical and similar industries by adding the InstrumEx and PowerEx ranges to enhance productivity when installing and maintaining all aspects of a safe electrical infrastructure.
Hawke International has secured the success of its connector ranges, among competitive high quality connector products, through innovative features that deliver tangible advantages in the field. Among these, the extended installation keyway prevents misalignment and potential contact damage, and visual five-position keying guards against misconnection of adjacent circuits. The connector’s flameproof barrier can be fully inspected in situ after assembly, allowing rapid visual checking. In addition, pin and socket inserts are numbered at the front as well as the rear to assist wiring and avoid potential termination errors. The special mating threads are a coarse pitch ACME thread, designed to prevent cross-threading or galling during mating. This extends the mate/un-mate lifetime of a screw connector while at the same time providing greater security than an alternative snap-fitting, for example.
At the heart of these high quality connectors lies Multi-Contact’s patented Multilam technology. Hawke design engineers chose to integrate contacts supplied by Multi-Contact and based on Multilam technology into these connector ranges, to ensure low impedance, durable electrical interconnections that would complement Hawke’s easy-to-use, high quality insertion and retention mechanisms. Phil O’Connor of Hawke International explains the crucial role of the electrical pin and socket interconnects in high quality connectors for ATEX and other high performance applications. “Absolute integrity in the electrical contact points is essential. We needed to achieve the best possible solution in terms of consistent and continuously low contact resistance over time, and resilience against the effects of oxidation, corrosion or other environmental hazards. Selection, therefore, was based on outright performance, to deliver the greatest reliability and low cost of ownership for our customers.”
Multilam technology implements an array of louvers held under spring tension, which exert a finite and tightly controlled force against the opposing contact. As a result, each contact displays a low and consistent electrical resistance that is constant over time and is also not affected by impurities such as surface oxidation. Since the total contact resistance is defined by the number of louvers in contact with the opposing contact surface, designers can determine the electrical performance of the connection accurately and precisely. Connector contacts that are built using Multilam technology are mechanically robust, and heat dissipation is also high thanks to the large number of contact points. Multilam technology has been proven in temperatures as high as 180 ºC, and temperatures up to 250 ºC can also be tolerated for short periods, such as during short circuit conditions. At the low end of the temperature scale, successful experiments have been performed using liquid helium at just 4.2 K. Multilam is also a compact technology, enabling low and stable contact resistance , as well as high durability, within a small outline. In addition, Multi-Contact can optimise the construction and properties to meet specific application requirements, for example by adjusting the thickness of the louvers according to whether high plugging cycles are required or whether few plugging cycles and permanent contacts are required. Optimisation for extremely high load conditions such as those encountered in switchgear applications, as well as for smaller power and signal connections, is also relatively straightforward and can be achieved cost-effectively.
Having identified this technology as the best possible solution for high-performance connectors destined for hazardous environments, Hawke engineers began work to integrate the contacts with the other innovative features of the ControlEx range. Multi-Contact supported the project, providing expertise at the design stages to create a bespoke Multilam-based configuration compatible with the characteristics of the connectors. One special requirement was to match the crimp sizes of the contacts supplied by Multi-Contact to the cable sizes required to serve Hawke’s target markets. “Multi-Contact was extremely willing to provide the support we required, and this was instrumental in quickly completing development of ControlEx, and subsequently the InstrumEx and PowerEx connector ranges,” comments O’Connor.
By working with technical staff at Multi-Contact in the UK, as well as at the Multi-Contact technology centre in Switzerland, Hawke International was able to quickly introduce its ControlEx connectors and immediately received favourable reaction from customers. Over time, the performance of ControlEx connectors in the field has confirmed Hawke’s choice of Multilam technology as the optimum solution to enable durable, high quality interconnects targeting oil and gas applications and other sectors where hazardous environments prevail.
As Hawke International moved to expand its range by developing the InstrumEx and PowerEx connector series for instrumentation and power distribution duties, Multilam-based pin and socket combinations from Multi-Contact were the natural choice. The Hawke PowerEx range targets applications up to 750V and 600A single-phase, and there are also three and four phase connectors rated up to 400A per phase. InstrumEx connectors are rated for applications up to 250VAC and 10A or 60VDC and 2.5A. Whereas the PowerEx connectors are optimised for high current carrying capabilities, the requirements for InstrumEx are dominated by the need for frequent mating and unmating for maintenance and quick changeover applications. This makes InstrumEx connectors a suitable choice for equipment that may be changed over from one sequence to another every few days. One example is automated machinery where Cleaning in Process (CIP) is implemented.
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