A fully containerised external blast room manufactured by Hodge Clemco has dramatically improved the equipment cleaning capabilities of the UK’s leading specialist piling company.

The company can now clean equipment before inspection and repair economically and efficiently without encroaching on production space. The new installation is environmentally friendly in producing no uncontrolled dust, and cost-effective because all spent abrasive is recycled. It is expected to pay for itself within two years.

The Companies piling equipment is maintained and repaired at its six-hectare depot. Most equipment returning from site requires cleaning before it can be inspected and tested — typical items are six-metre-long augers from 300 mm to 1250mm in diameter and boring heads from 300mm to 2400mm in diameter.

In order to meet the cleaning needs without taking production space, Hodge Clemco designed a self-contained installation which is fully weatherproofed and so could stand outside the factory.

Blasting takes place in a fully welded containerised booth, 9.34m long x 3.66m wide x 3.66m high, with double doors at one end and a side door into the plant room beside it. Safety interlocks prevent blasting when doors are open, and rubber curtains protect the walls against abrasive ricochet.

An IND 2040 SGV static blast machine is linked directly to the outlet of the abrasive storage hopper to form an enclosed feed system into the dish of the blast machine. This model, which has an 82 litre hopper, was chosen because it met abrasive capacity and workspace considerations.

The equipment has a RMS2000 remote-control system, which enables the operator to turn the blast machine on and off at the nozzle, and a P20 pressure regulator, which allows air pressure to be controlled between 7psi and 110psi to suit the material to be cleaned.

Chilled iron abrasive, which is particularly dense and hard, is used in order to clean the heavily contaminated equipment quickly and effectively.

High-performance dust collectors, comprising two bag-type units rated at 6000cfm and giving a linear air-flow of 42ft/min, maintain good visibility and efficient working conditions for the operator. The collector has a filter area of 84m², which provides a filter speed of 6.7ft/min.

In order to minimise abrasive wastage and also improve both the quality of the finish and the working environment, an IND 200P vacuum recovery system has been included. Periodically the operator sweeps expended media into a small hopper sunk into the blast room floor, and the material is then cleaned and returned by vacuum to the silo mounted above the blast machine.

The efficiency of the recovery system has allowed our client to use highly effective but relatively expensive chilled iron abrasive and still make considerable long-term savings in abrasive costs. ‘Although the cost of chilled iron is four times that of expendable abrasive, it can be re-cycled many times, whereas expendable abrasive can only be used twice, at best’, said Hodge Clemco applications engineer Neil Scragg. ‘Re-using the abrasive in this way dramatically reduces the cleaning costs for every square metre of metal processed in the room’.