Canadians eye gas cooling to raise throughput
As the developers of nitrogen gas cooling are learning how to optimize the technology, several Canadian extruders are said to be eyeing the system.Auxiliary equipment supplier Conair and Material Enha...
As the developers of nitrogen gas cooling are learning how to optimize the technology, several Canadian extruders are said to be eyeing the system.
Auxiliary equipment supplier Conair and Material Enhancement Inc. introduced the nitrogen gas cooling concept last year at NPE.
Since then, they’ve learned that the system generally works best when combined with traditional water cooling.
“At melt temperatures above 250 F, water is a more efficient cooling medium,” says Ernie Preiato, Conair’s vice president extrusion. “For secondary cooling, from 250 F to ambient temperature, nitrogen gas is more efficient.”
One benefit to using a water/nitrogen hybrid system, instead of all gas cooling, is that the tooling and process remain the same for the primary cooling step.
With a hybrid system, Preiato says processors with can expect 20 to 30 percent higher throughput, assuming the extruder has that additional capacity. A hybrid system does cost more to run ($7-10/hr. vs. $2-3/hr. for water cooling), so you need the capacity for a rate gain to make it worthwhile, notes Preiato.
Most commonly, the nitrogen supply comes from liquid nitrogen tanks that are stored outside of the plant. The gas supplier is responsible for installation and maintenance of the tanks and plumbing to the cooling equipment. The Conair/MEI units convert the liquid nitrogen to gas before it enters the cooling zones, so operators do not come into contact with the liquid nitrogen. As a gas, nitrogen is non-flammable, non-explosive and inert.