spare that can be switched in quickly if one of the operating pumps were to fail. Tis design proved its worth the first time Chassix’s new cooling system was turned on after installation. “Tere were the normal hiccups with installation,” Roop said, “but they were handled. Tere was no panic, even when one of the new pumps failed at startup. Because we had planned for the cooling system to operate fully on just two of the three pumps, we quickly isolated the defective pump with the valves installed for that purpose and turned on the fully-connected backup pump, keeping the new cooling system in operation. Because we had purchased a spare pump that was stored nearby, we were able to replace the defec- tive pump within the hour. It was a good demonstration of how well the system was designed to keep doing its job even with a pump failure.”
Backup and Emergency Cooling Because effective cooling is so critical
to the safe operation of an induction melt shop, it’s vital that a backup or emergency cooling system be in place in case an equipment or power failure shuts down the main cooling system. A common backup covering both pump and power failures is a direct connection to a city water supply that is either automatically or manually turned on to flow through the furnaces and other equipment served by the main cooling system. Tis is a once- through-cooling arrangement with the heated water being routed to a drain or other outflow site. Another common backup system for
power failures is a battery (in very small systems) or generator that switches on to continue running the pumps in the main cooling system. Many metalcasting facilities also maintain backup cooling pumps that can be switched in quickly if an operating pump in the main system fails. Chassix is able to turn on a city water
supply for backup cooling in the event of a power failure. Its new cooling system also incorporates an online backup
casting production. Installation was scheduled for a holiday weekend. To meet the space and time
Limited access to a small working area complicated Chassix’s cooling system installation.
pump that can be switched on quickly if another pump fails. A stored spare pump is ready to replace any failed pump.
Installation at Chassix
Ideally, installation of a new induction melt cooling system should take place in a large, flat area, with ample space to stage cranes and other heavy lifting equipment. Tere should be plenty of power available for the pumps and fans, and direct connection to city water sup- plies for makeup water to keep the sys- tem filled and provide emergency water in case of equipment or power failures. Tis was not the case at Chassix,
which wanted the new cooling tower and pumps installed adjacent to the old tower that was being taken out of service. Tis allowed an easy connection to the exist- ing plant cooling water piping, electrical network and control interface, but it posed a challenge. “Te installation site was a tiny space
adjacent to the old cooling tower and hemmed in by that tower and by the scrap yard with its rail spur,” explained Mark Foster, site supervisor, EMSCO. “Te only access was by a narrow alley- way. Another obstacle was a drainage cul- vert that ran through the only spot where the new cooling tower could be placed.” Because the old cooling system
had to be completely shut down before the new system could be connected, a full plant shutdown was required. Tat shutdown had to be as brief as possible to minimize its effect on
challenges, every step of the installation process was care- fully planned. Rail tracks were removed, and footings for the cooling tower were placed to avoid the drainage culvert. To simplify handling and speed assembly at the Chassix site, the three pumps were delivered and moved as modular units com- plete with their own piping and electrical connections. And for the assembly work at the site, a just-in-time delivery sched- ule was set up, and equipment lay-down and staging loca-
tions were cleared and prepared. Special compact material handling equipment was used to move everything as needed in the small working space. When it was time to shut down the old cool- ing system and the entire metalcasting operation, all that remained to be done was to make the new connections to the plant pipes, power and controls. Te project was completed on time and within budget. According to Roop, the new cooling system continues to work flawlessly. “It does what we were told it would do,” he said. “Te new system has the capacity we need and the water is staying cooler,” said James. “We have not had to shut down due to water over temperature. We can run all of our equipment all of the time, even in summer. Production is no longer impacted by cooling problems.” As melt maintenance supervisor,
Shawn J. Murray is responsible for keep- ing everything running, including the cooling system. “With the old cooling system, we could not run all the furnaces at once,” he said. “And we still were having 50 to 60 high temp alarms per day. Now, with the new cooling system, we can run everything all the time. It has greatly reduced furnace trips and completely eliminated the need to shut down due to a lack of water at the right temperature. With the new cooling system, I can keep our furnace temperatures under control and all of our equipment running.”
February 2014 MODERN CASTING | 37
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