Rapid International Ltd

 

Rapid International has just completed a new 800 tonne cement storage silo at Southside, Guernsey for Ronez Ltd., a subsidiary company of Aggregate Industries plc.

The 640 m3 silo was designed specifically for this application. The Rapid design brief had to include the maximum diameter to enable the 800 tonne silo to be the same height as the three existing 500 tonne silos. Rapid had also to manufacture the silo in sections to facilitate the shipping and limited vehicular access. Another design constraint was to have six symmetrical legs to enable a reinforced concrete ring plinth foundation. In addition to the above Rapid had to consider the limited availability of cranes on the island and to stringently adhere to construction, design and management regulations.

The design included a 10mm cone section supported from a ring beam. The vertical sides and roof were manufactured from 6mm steel plate. A 45m2 reversed air jet fan assisted filter was provided to allow the venting of the 168mm diameter fill pipe via diverter valves to the ship discharge line. Silo level indication was provided using Vegaflex guided microwave beams.

Rapid also provided an 80 tonne per hour discharge screw conveyor to the existing loading bellows to enable the filling of road tankers. As part of the same project all three of the existing silos were completely rewired with a new Allen Bradley SLC500 control system complete with starter panels, pneumatic panels and new Vegaflex guided microwave level sensors.

 

To deal with the coastal environment all mild steel was given four coats of epoxy zinc phosphate primer and a finish coat of polyurethane semi gloss. All electrical panels and isolators were supplied in stainless steel. The project was supervised on site by Rapid’s Mr. Gordon Mackley.

Mr. Steve Roussel of Ronez and his personnel provided excellent co-operation and assistance in dealing with the shipping company and local suppliers.

The project was completed on schedule and within budget with Rapid personnel returning only to commission the first ship discharge using the new control system. Ronez were able to continue to use the existing silo system throughout the building programme with minimal disruption.