About Main Control Valves
They go by a couple different names but they are generally similar: Control Valves, Directional Control Valves, Hydraulic Control Valves or Hydraulic Directional Control Valves.
Control Valve Purpose in Life
If you're a control valve, your main purpose in life is to direct hydraulic force to do work. Hydraulics 101 tells us that while hydraulic force is very powerful, it isn't all that intelligent.
Oil will always follow the path of least resistance!
Inside a control valve, the tolerances are extremely tight - 0.0005" or better. Five ten-thousands of an Inch. Or half of a thousandth of an inch. This is a fraction of the width of a human hair! This diagram gives you a visual on the tolerances inside a hydraulic control valve.
The tolerances are so tight because a metal-to-metal fit must hold back hydraulic oil at 4500 psi or more. Variable or fixed displacement pumps create the flow to be directed through the controlvalve. Any scoring or imperfection on the spool will create a path of lower resistance. The oil will choose to leave the spool or go back to tank instead of doing the work the machine operator needs.
Types of Valves Repaired
Follow this link to see the hydraulic control valves we've rebuilt.