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[May 2001]
Pilkington's Tiles Uses Peristaltic Technology for Slip Processing
Pilkington's Tiles has switched to peristaltic technology to improve production processes at its Swinton site in Manchester. A total of 16 Watson-Marlow Bredel peristaltic hose pumps are now being used to control the slip at every stage of the manufacturing process.
Three 65mm bore pumps deliver slip from the blungers to holding tanks. These pumps are located four metres below ground, originally a necessity to provide the flooded suction conditions required by the pumps previously employed in this application but not required by the hose pumps. The slip is then pumped through to a spray dryer - 20 metres above the holding tank - by another SP65 pump.
The method of pumping slip prior to this installation involved a combination of air operated double-diaphragm pumps and rubber lined centrifugal pumps. Pilkington's found that spares consumption and operating costs were running at alarming rates. Also, because of high levels of wear, there was a risk of metal particles from eroded pump components contaminating the product. The peristaltic method is also reportedly helping to reduce power costs - the pumps are fitted with 7.5kW fixed speed motors as opposed to the 18kW motors previously used on the centrifugal pumps.
Two further 40mm bore Watson-Marlow Bredel peristaltic hose pumps handle slip re-worked from scrap product. One pumps from the re-work tank to a vibrating sieve which drains into a holding tank. The second pumps the screened product from the holding tank back into the spray dryer feed tanks.
At the final stage, waste from the spray dryers is pumped to an effluent treatment plant. This waste is highly abrasive with variable solids content, and the pumping temperature can rise to 60°C. Coupled with the fact that the waste pump is often required to with dry suction, this is said to have meant that it was a huge challenge for the previously used system.
The crucial factor in achieving both accuracy and self-priming capability in a peristaltic pump is the speed at which the hose regains shape when compression ceases. Hose recovery should be virtually instantaneous, not only when it is first fitted into the pump but throughout its service life.
Since the installation, Pilkington's has experienced a decrease in downtime, reduction in spares costs and an overall improvement in quality standards. The unexpected bonus to these savings was a considerable reduction in power consumption costs where the hose pumps replaced rubber lined centrifugal pumps.
Web site: http://www.watson-marlow.co.uk
ENDS