Hydro-Gen Engineering Ltd, a specialist in industrial water filtration in the UK claims it has been working closely with several customers in the plastics industry. The initial involvement was to improve water quality to keep the closed loop system clean, to stop flow meters fouling and flow control valves blocking, but as a number of installations came on-line with a side stream polishing system, the group says that other benefits came to light.
By using clean cooling water, machine speeds improved during the trials as curing time came back towards the original design time, where previously, curing time had to be extended as cooling was becoming less effective due to poor quality water.
To put this extension to the curing time into perspective, the group claims that a coating of particulate on a heat transfer surface of only 100 micron (about the width of a human hair) can reduce heat transfer by 15%, so if the cooling efficiency of a system reduces production by just 15% this would mean that for every 1000 hours of production 150 hours are lost, which over a year is some 1314 hours. In a production facility with ten machines this means one or even two machines are being used just to cover production lost by extended curing due to poor water.
Another common problem is the onset of biological growth within the system. One solution is to routinely drain the whole cooling system, flush it, then refill it with fresh water. However in systems that also contain chemicals (such as biocides and antifreeze) these chemicals are in effect thrown away.
Hydro-gen claims that the system best suited to resolving these issues is a side stream option which can polish the water to below 1.0 micron. This is an advanced technology which is self-cleaning and when installed correctly can reportedly show significant benefits within days of installation, ensuring a clean cooling system, reducing maintenance down-time and maintaining production levels as well as reducing water and chemical losses.