We saw how essential a cooling system is to the International Space Station in December 2013, when one coolant pump failed. That left only one other pump to provide cooling for the station’s vital electrical and life-support systems. This required a crew member to make an emergency spacewalk to swap a spare for the pump that had failed. With its new pump in place, the station was back in the space exploration business.
While it might not be rocket science, when it comes to cooling, induction melting is as dependent on an effective cooling system as the International Space Station. Without adequate cooling, induction furnaces are not able to operate. And in the worst cases of cooling system failures, furnaces have been damaged or destroyed, endangering workers and causing significant damage to the foundry.
Metalcasting cooling systems normally operate quietly in the background and receive regular attention only from the maintenance personnel tasked with keeping them running. The goal for this article is to provide useful insights into the design and operation of effective and efficient induction melt shop cooling systems, with real-world illustrations drawn from a new system installed at Chassix Columbus Casting Operation, Columbus, Ga., U.S. Chassix is a $1.2 billion global company headquartered in Southfield, Mich., serving automotive customers from 25 locations in eight countries. Its Columbus facility melts 240,000 tons of ductile iron per year.
Cooling System Basics
Induction furnaces of all types and sizes normally are cooled by water flowing through the furnaces’ coils, which are made of heavy copper tubing. These coils generate high levels of heat, principally from the enormous electrical currents flowing through them and only to a much lesser extent from heat produced by the molten metal held in the furnace. Induction power supplies also require water cooling of their electrical components. Without an effective cooling system, induction furnaces will not operate.
At its most basic level, an induction furnace cooling system includes pumps circulating water through the furnace to absorb heat and on to a cooling tower where that heat is released. But to be safe and effective, a cooling system must incorporate a variety of vital subsystems. These include:
- Filters and other devices to keep the water clean and flowing.
- Heat exchangers, inline heaters and cold water diversion valves to maintain the optimal water temperature.
- Automatic city water makeup to keep the cooling system full.
- Flow sensors, pressure gauges, thermometers, water meters, and other monitoring and control devices needed to be sure it’s all working properly.
- An emergency backup system to maintain furnace cooling in the event of pump failure or power outage.