Machine builders and maintenance engineers in the pulp, paper, and sawmill business rely on a variety of motion-control components, including servo valves, to operate calendar roll machines, slitters, cutters, tension controllers, lathes, and chippers. Current machinery generally uses analog electronics (i.e., electrical feedback valves) or no integrated electronics at all (i.e., mechanical feedback valves). Unfortunately, this equipment could create problems with extended downtime and the inability to maintain high throughput rates. Some see a solution in microprocessor-based digital electronics.

To capitalize on this desire to digitally upgrade a mill's motion-control systems, Moog engineers have developed four new direct drive valves (DDVs). These new valves have internal electrical contacts that resist extreme vibrations and extra potting on critical components. Flow ranges from 1 to 42 gpm and maximum supply pressure is 5,000 psi.

The advantages customers experience when upgrading to digital valves include better static and dynamic performance via higher resolution, and better pressure control. The new model valves also offer diagnostics and internal valve error handling. In addition, maintenance is reduced because the valves do not have hydraulic pilots, so they better resist contamination and there are no small orifices to clog.

Overall, there’s less downtime, thus improving productivity. And by using dynamic motion control, the valves can handle fast cycle times.