Secret spring system separates solids

Anticipating demand for a more economical particle size analysis system Haroun Mahgerefteh set about devising a simple mechanical device based on a spring.

With researchers Katem Patel and Ali Shaeri, he won a DTI Smart Award to finance the development. 'We are now talking to manufacturers' he tells PE. The separator, which Mahgerefteh estimates could be in production in under two years. The prototype has cost only about £1000 to construct just a quarter of the price of an equivalent sieve.

'The problem with sieves is that they are not capable of on line operation,' he says. 'To sieve your material you need to take it out of the process, so if you find that the materials are off spec, it may be too late to do anything about it.'

The 'confidential' device separates particles of diameters between 35-1200 m at a resolution of 10 m. The team has performed experiments with glass, cement, flour, tea and sawdust.

'The other key method, by laser, can only test about 0.1g of material at a time. In a one tonne sample that is not really representative,' he adds. In the spring testing system he can work with about 10-15g.