The plant was using 15 die-casting machines ranging in size from 60 to 650 tons. Die-casting machines are prone to heat buildup during production, so to keep the machines running smoothly, cooling water is supplied from a roof-mounted cooling tower. The system was susceptible to various suspended solids that accumulated in the heat exchangers in the machine, plugging them and preventing the flow of cooling water, causing damage to the tools. As a result, the machines spent more time being cleaned and repaired than in production.
The first step to solve the problem was to install a simple manual inline filter on one of the more critical machines to determine the main contaminants. The filter clogged within hours of being put online. The major contaminant was wood chips from the cooling tower, which was subsequently replaced.
The system was started again, but the manual filter continued to clog. Year-round contaminants included sand, silt, algae and other suspended solids. In the spring, the problem was compounded by the presence of tree pollen that found its way into the system. As the water flowed through the system, it picked up rust, scale and other corrosion by-products, further adding to the problem.
The decision was made to install a self-cleaning water filter with a 50 micron fine screen. Line-pressure-powered and capable of handling up to 350 gal/min, the unit was equipped with an automatic built-in bypass. Should a situation ever arise whereby the filter is unable to clean itself, the bypass would open, ensuring a continuous flow of essential cooling water to the die-casting machines. Orival offers several options for control of the bypass, including hydraulic, electric and with activation of a local or remote alarm.
The cooling system and all machines were cleaned and put online with the new filter. Because of its user-friendly design and the control system, filter installation and startup was simple. In addition, the small manual online filter was fitted with a clean element to be used as a check filter.
The filtration system solved all of the problems with plugging of the cooling lines. The water in the system stays clean all year long, even in the spring. The small manual inline filter, now used as a check filter, has never had to be cleaned since the installation of the filter in September 1996. One of the major benefits of the filter is the extra filtration provided by the caking action.
The cake creates the equivalent of a finer mesh. Orival filters have a capture ratio of 10 to 1, which means that a 100 micron screen with a cake buildup will remove particles as small as 10 micron.
The die-cast machines are now run without fear of clogging the water lines. Machines that were previously run at 500 shots/hr now run at more than 600 shots/hr, allowing for increased production. In addition, the system is fully automatic, allowing the maintenance staff to focus their energies on other tasks.
For more information about filtration systems from Orival, call (800) 567-9767 or visit www.orival.com.