Filter cleans as it filters
A pond filter that cleans itself – it could have a much wider application base
Problem: All filters have a tendency to become clogged, with some being disposed of and replaced.
The filters in the average domestic dishwasher have to be taken out periodically, cleaned and replaced. Industrial filters, on the other hand, are usually back flushed, in order to maintain continuous operation. This usually either requires temporarily ceasing normal operations or maintaining two or more filters in parallel, so that at least one is always on stream.
Solution: Jim Hosford, formerly a Dorset dairy farmer, came up with the idea of a slurry pit filter which cleans itself.
His breakthrough idea was to take some of the output flow from the pump and direct it back in to the filter assembly, causing a rotor to rotate.
As it rotates, the emerging jets of water impact on the inside of the filter screen, momentarily back flushing those parts.
Realising it was a good idea, he made a few pre-production prototypes in aluminium and test marketed the concept by selling them at the Royal Show at Stoneleigh. He then went to Rodd Industrial Design in Lyndhurst, who developed a version in plastic.
As well as greatly cutting the cost of production, the idea was also enhanced by the addition of a ‘gunge’ trap – a small detachable bucket beneath the filter unit to collect unwanted material.
Applications: Hosford no longer farms dairy cows. Sales of his Rotorflush filters have reached 2,000 per week. Most go into the pond market, where they filter water being drawn into fountains. The idea, however, has great potential in any industry where fluid has to be filtered and Hosford has just told us: “We are in the final stages of getting some new products ready for the industrial market that we are hoping to launch this summer.”
Recommended retail prices of the current products are £29.95 for filter only, £19.95 for the gunge trap or £39.95 for the complete system. TS
