Water Quality Matters
Due to its good heat transfer properties, water ideally suits cooling and regulating the temperature of plastics processing equipment and molds.
Yet when it comes to the water quality, it is often an afterthought or a neglected consideration, even though it is an essential factor in the performance of coolant circulating systems.
Scale build-up in channels and circuits rapidly leads to reduced flow and consequently to significant performance deficiencies. For example, did you know a layer of limescale just 0.060” thick can more than halve heat transfer?
What About Water Treatment Considerations?
Water chemistry can affect cooling in these ways:
Microbiological Issues – Microbiological Influenced Corrosion (MIC) is caused by the corrosive effects of microbiological growth on metal components.
Scaling – Minerals can precipitate water and deposit it onto heat transfer surfaces, restricting coolant flow and reducing heat transfer.
Corrosion – Undesirable water chemistry can attack metal components of the system. MIC mentioned earlier is one type of corrosion. In addition, galvanic corrosion can occur from the electrical interaction of different metals with the coolant.
The use of ethylene or propylene glycol complicates the water treatment process. Glycols are known to make the water more corrosive. Some glycols have corrosion inhibitor packages added to them.
Water treatment issues are unique to each system due to the chemistry of the local water supply and individual plant conditions. The Association of Water Technologies is a professional association dedicated to the water treatment industry. They provide training and technical information and can assist you in reaching a local water treatment professional.
Mold cooling is “low hanging fruit” for improving profits. Cycle times can be reduced, uptime increased along with improved energy efficiency. From the outset take the time to know how much flow you need for turbulence and measure the flow in each cooling circuit. Then, establish minimum flow rates for all cooling circuits and incorporate this information into setup sheets.
Simple, affordable tools for turbulent flow measurement and flow regulation are readily available from molding supply distributors like Smartflow. You can also visit their website and click on technical documents for previously published trade articles and free downloads to assist in your quest for process improvement.
We recommend managing your cooling water quality with a professional. To find a water treatment professional near you, consult the website of the Association of Water Technologies (AWT).
For more helpful information and smart tools, visit the following links from Smartflow USA: