By Gary Alexander
Proper valve sizing for a hydraulic system can be a balancing act between system efficiency and cost. Large valves reduce pressure losses in the system which rob power and create excessive heat, but the valves can be very expensive. Smaller valves reduce system cost but cause higher pressure drops. These pressure drops waste power, create heat that may require a heat exchanger, and increase cost. Remember – whenever there is a pressure differential in a hydraulic system that does not result in work being performed, that pressure differential is directly proportional to the heat loss and horsepower wasted.
Here are some basic guidelines for valve sizing when designing a hydraulic system. These rules are particularly true for directional control valves: