Limit switch augments explosive atmospheres range

21 August 2008

Cortem Group’s range of products, suitable for installation in hazardous areas with potentially explosive atmosphere, grows bigger thanks to a new series of compact limit switches. Traditional Ex-d limit switches have a big enclosure, while Cortem Group could design explosion proof limit switches as small as non-explosion proof industrial products, thanks to new production technologies and the use of materials such as aluminum alloy UNI 4514 and stainless steel AISI 316L.

They are strong, quick to install and easy to wire, reliable with passing of time. Limit switches are in fact subject to damage due to wear and tear, because their mechanical and electrical components work strongly and continuously. Their safety may therefore be compromised, which is not good in areas with potentially explosive atmosphere.

Cortem Group’s researchers simulated the working of limit switches mechanical and electrical parts in the worst mechanical and thermal conditions. Resistance to corrosion and reaction against continuous vibrations has been tested, both with constant ambient temperature and in presence of thermal shocks. Plastic parts and sealing fittings are able to withstand temperatures between -30°C and +100°C.

Besides such additional tests, the product has been tested according to the Standards IEC 60079-0 and IEC 60079-1 for safe use in Zone 1 and Zone 2 in presence of gas, vapors and mists and to the Standards IEC 61241-0 and IEC 61241-1 for safe use in Zone 21 and Zone 22 in presence of flammable dusts.

SIRA laboratory certified the limit switches, which are also conform to all requirements of ATEX equipment of Category 2 for gas and dusts. They are available in 10 models, which vary according to the actuator. If we also consider the contacts combinations, then sixty models are available. All models have a maximum control speed of 0,5 m/s, from 0,30 Nm to 50 Nm.