IN THE OPERATION of water-cooled extrusion equipment, severe system corrosion, mineral scale deposition and water passage fouling can, and often does, occur. While the use of soft and high purity waters as the cooling medium reduces scale deposition, the aggressive nature of these waters at elevated temperatures and variations in their purity both contribute to premature component corrosion and failure.
Ideally, once optimum extruder zone temperatures are achieved, the extrusion process should proceed adiabatically. However, in actual applications frequent cycles of heat input and heat dissipation are required in order to maintain optimum barrel zone temperatures. Heat input is achieved electrically through imbedded heating elements in the barrel zone heater/cooler. Cooling is achieved by the entry of cooling water into small diameter coils also imbedded in the zone 'saddle' castings.
At zone temperatures as high as ~600°F, cooling is not achieved in a conventional water/heat transfer model, but rather through the evaporation of a small quantity of water that is regulated into the heater/cooler from an inlet manifold. Because virtually all of the cooling is achieved by evaporation in the zone heater/cooler, properly engineered waters® are vital for continuous and trouble-free system operation.
Chemagineering Corporation initially entered the Water-Cooled Extrusion Industry in the 1990s through the use of CH-7:54® Industrial Cleaner as a non-hazardous chemical descaler in the cleaning of barrel cooling water systems in chemical manufacturing facilities. Upon completion of the cleaning and descaling procedure the extrusion cooling water systems were maintained with a high purity water-based blend of organic corrosion inhibitors.
Extruder Maintenance Programs utilizing CH-7:54 Industrial Cleaner and Extrusion Performance Fluids® have been successfully extended into the Plastics Industry. Specific products utilized to clean and restore water-cooled extruders as well as maintain them include:
CH-7:54 Industrial Cleaner — A non-hazardous, near-neutral cooling water system descaling and iron oxide removal agent. CH-7:54 is typically used to clean isolated, out-of-service severely scaled and fouled systems. Many successes have been also documented for in-service cleaning.
FoamBUSTER® Cooling/Process Water Antifoam — In the typical application of chemical cleaning products, mild-to-moderate recirculating water foaming may occur. When sufficient foam occurs that impedes the cleaning process and/or water recirculation, FoamBUSTER can be easily applied to control that condition.
EPF-825 Extrusion Performance Fluid — An inhibited all-organic high purity water-based coolant designed to prevent barrel cooling water system corrosion and mineral scale fouling.
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