Explosion-proof controls for Cleveland Cascades

A RANGE of hazardous-area electrical equipment, including terminal boxes, control stations, emergency stop controls and enclosures manufactured by Cooper Crouse-Hinds (CEAG), are being used by Cleveland Cascades Ltd on their range of custom-designed, retractable loading chutes for the handling of dry bulk materials in various ship, silo, rail and road tanker loading applications.

‘We’ve been purchasing CEAG equipment for many years now, via Scattergood & Johnsons Ltd, our local distributor in Leeds,’ commented Ray Ollis, electrical design engineer at Cleveland Cascades Ltd.

‘When it comes to offering loading chutes for hazardous environments, we provide a detailed design specification to Scattergoods, who then source the required control stations and terminal boxes from CEAG. Up to now, the CEAG equipment has been very reliable and we’ve never had a single problem from the customer once we’ve installed the system.’

The Cleveland Cascade loading system constrains material flow in a zigzag path through inclined cones to limit the flow velocity and therefore prevent particulate separation, material degradation and segregation. In this way dust generation is virtually eliminated at source, without the need for expensive and energy-intensive dust extraction and filtration systems.

‘We normally have to retrofit our loading chutes, which involves a lot of engineering effort, both mechanical and electrical,’ continued Mr Ollis. ‘For example, if the customer needs to load 200 tonnes/h of cement to a tanker, we have to design our chute and associated control equipment to cater for this. This means we sometimes have to use customized control stations and junction boxes.’

The chute controls can be integrated with the customer’s existing PLC equipment or operated independently with a dedicated controller. The controls are normally be located in a gallery, close to the conveyor, or remotely, but in either situation, and especially when ATEX certification is required, CEAG control stations are used, which typically comprise emergency stop-start controls, reset and raise controls, stainless steel or plastic enclosures (depending on the application) and terminal boxes.

According to Mr Ollis, people are starting to wake up to the ATEX regulations and more jobs are now including this type of hazardous-area equipment. ‘Out of the nine enquiries currently on my desk, three require ATEX-approved control equipment,’ he said.