Counterbalance Valve Performance

A 3:1 pilot ratio means that the spool area acted upon by the pilot pressure is three times larger than the spool area acted upon by the system load. This means that the force generated by the pilot pressure and trying to open the valve is three times more effective than the force generated by the load, which is also trying to open the valve.

A 10:1 pilot ratio means that the force on the spool, generated by the pilot pressure is 10 times higher than the force generated by the same pressure from the system. The result is that with a 10:1 pilot ratio the load starts to move at a lower supply pressure and with a lower pressure drop across the valve. Consequently the 3:1 pilot ratio tends to be more stable and should always be used except in very stable motor circuits.