Patent ID: 6357276
Filing Date: 2002-03-19
Classification: F15B

Abstract:
A system for calibrating a independent metering valve comprising:an actuator having first and second actuating chambers; an input port; an output port; a pair of control ports; a first independently operable electrohydraulic displacement controlled spool valve disposed between the input port and one of the control ports and being moveable between a open position and a closed position; a second independently operable electrohydraulic displacement controlled spool valve disposed between the input port and one of the control ports and being moveable between a open position and a closed position; a third independently operable electrohydraulic displacement controlled spool valve disposed between the outlet port and one of the control ports and being moveable between a open and a closed position; a fourth independently operable electrohydraulic displacement controlled spool valve disposed between the outlet port and one of the control ports and being moveable between a open position and a closed position; and a controller for positioning three of the spool valves and slowly moving one spool valve from the closed position toward the open position until fluid from one of the actuating chambers is allowed to flow through the one spool valve and the position at which fluid flow is produced therethrough is used for calibrating the valve.