Companies operating on a global scale place high demands on the explosion protection components installed at their subsidiaries. This is particularly true of OEMs who cater for clients around the world. Take the case of a manufacturer of agitator systems, for example, whose customers needed to be provided with universal solutions for Zones 2/22. These agitators are used to mix substances for the pharmaceutical industry, for instance, in processes where hazardous dust or gas atmosphere is formed. The switch boxes required for these hazardous areas had to house devices with high power loss, such as frequency converters. Using Ex-d enclosures was out of the question. What’s more, the customer wanted to be able to operate the system directly on site at the plant, meaning the switch boxes could not be positioned outside the hazardous areas. Another crucial requirement was suitability for clients anywhere in the world. When it came to implementing the switch boxes, therefore, the choice was clear: the manufacturer opted for the Bebco EPS 7500 series purge and pressurisation system, which was specifically developed by Pepperl+Fuchs with these and similar market and customer requirements in mind.
Compact, universal, efficient
The purge and pressurisation system is approved for Zones 2/22 and Classes I/II, Division 2 and can be used universally in process plants the world over. It comprises a robust, ultra-compact control unit, an enclosure protection vent and a valve. The innovative purge system is designed for enclosures measuring up to 12.7 m³ and thus covers most potential requirements for purge and pressurisation systems or switch cabinet solutions in the field of process automation. The compact 7500 series is easy to operate and incredibly reliable and efficient. It offers excellent – and fully automatic – protection for electrical devices such as motors, drives, control panels or cabinets and gas analysers. Whether for gas or dust protection in the oil and gas, chemical, shipping or offshore sectors, the Bebco EPS 7500 series is ideal for applications in the international process industry – applications where a less practical and more expensive form of explosion protection was previously unavoidable.
One crucial advantage for global use is the fact that the 7500 series is operated with a universal AC/DC power supply unit, so that any voltage from 90 to 253 V(AC) or 18 to 33 V(DC) is possible. It also has all the necessary international certifications from independent testing authorities such as Atex, IECEx, NEC and CEC. For OEMs and other companies with subsidiaries around the world, this solution provides a single system that can be installed on any continent – a major advantage. This greatly reduces the logistical and technical planning effort for global players and adds up to universal explosion protection that meets the requirements of different regions.
The purge and pressurisation system can be operated both fully automatically and manually. It prevents dangerous gases and dusts from entering the enclosure, and monitors – or rather controls – the pressure through dilution as well as by maintaining a continuous flow. That way, the classification inside a protected switch cabinet is reduced to that of a non-hazardous area. Users can set up to four pressure points in five selectable programs. As soon as the pressure falls below a defined limit, the system sounds an alarm. If it drops due to a fault, the plant will automatically disconnect from the network with no need for manual intervention, thus avoiding potentially dangerous situations. If defective cable glands or seals are the cause of a pressure drop in the switch cabinet, not only is an alarm triggered but the pressure can also be temporarily compensated due to the built-in leakage compensation technology. The operator can then take appropriate action before the fault leads to a failure or a dangerous scenario.
Touch display with status LEDs
The extremely compact housing of the control unit is just 150 x 100 x 50 mm in size and made of powder-coated aluminium. This robust device is built to withstand the harsh conditions in the process industry and is equally suitable for both panel and external mounting. Despite its small outer dimensions, the unit boasts an extra-large touch screen, ensuring that the status indicator is easy to view and that operations be completed quickly and easily. The conditions in the enclosure to be purged can be monitored using a combination of bar charts showing the pressure levels and various default programs, enabling rapid adjustment to any situation. Four status LEDs next to the display provide quick information, e. g. by indicating whether the exact pressure required for operation is present or only the bare minimum, too little or too much. They are visible from a distance of more than 20 m, so that the status of the purge and pressurisation system can be recognised without having to approach the enclosure.
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Author: Alexander Aust
EPE & Solutions,