Close The Loop On Clean Cooling Water


A plastics molding plant runs on more than electricity—it runs on water. Clean water. Lots of it. Consider even a small plant with three 165-ton and three 120-ton hydraulic injection presses. Each typically requires a continuous supply of 100 gal/min to cool the hydraulic system and the mold. Assuming a two-shift operation, that’s 96,000 gal a day and more than 30 million gal a year! With that much water going through a plant, water quality has a direct and significant impact on the plant’s operations.

Dirty water blues
Water contamination can have serious and costly effects, such as equipment damage and even failure, not to mention worker health problems. Heavy particulate matter and corrosive agents in process water can wreak havoc on your plant’s productivity.


The following conditions suggest that your plant is suffering from water contamination:

1.  Clogging of high-heat, low-flow areas.
2.  Clogging and/or corrosion of process components.
3.  Gelatinous deposits.
4.  Worker health complaints such as fever, chills, coughs, muscle aches, headache, tiredness, loss of appetite, and even pneumonia.


Most water-contamination problems result from the open-loop process cooling systems common in U.S. plastics plants. An open-loop design means that your molds and other process equipment are exposed directly to whatever contaminants are present in your water supply. If you have a cooling tower, additional contaminants can enter the water from its repeated exposure to the outdoor air.


If you have an open-loop process cooling system design, you must regularly monitor and treat your water supply to control lime scale and other mineral deposits, as well as corrosion, microbiological growth (algae, bacteria, fungus, and molds), and accumulation of suspended solids such as airborne dirt and debris that is washed into the cooling-tower water.


In addition to the cost of water monitoring and treatment, an open-loop process-cooling system burdens your plant with costs for sewage disposal and equipment maintenance, in addition to the cost of water usage. These operational costs—not to mention intensifying environmental regulations—have become an increasingly significant management challenge to plastics processors.