A na-eji valvụ a mepee ntinye na sekit hydraulic (Valve na-emechikarị).
Ozugbo a na-emegharị spool ahụ n'ụzọ na-arụ ọrụ, ọ na-enwere onwe ya site na P ruo A. Enwere ike iji ya mee ihe maka: a) ịtọ usoro nke 2 actuators b) dị ka njedebe nke valvụ strok, ebe a na-ejikọta mmiri na tank
