BARKSDALE 6147R3H03 - 2 POSITION DIRECTIONAL CONTROL VALVE

Interflow in a Barksdale Shear-Seal® valve is a small amount of fluid flow from the Pressure A and B ports to the return port through the clearance between the rotor and the body. This interflow occurs whenever the valve is shifted from one position to another or when the valve is being used for throttling. This is due to the Shear-Seal® in the valve being only partially covered by the rotor. Interflow is not leakage and does not occur when the valve is fully engaged. The interflow in a Shear-Seal® valve is beneficial in that it reduces the hydraulic shock or “ water hammer” that can occur when a valve is closed rapidly. The small amount of interflow between ports acts as a cushion as the fluid flow is stopped in the system. Non-interflow valves are constructed with Shear-Seal® s using a much smaller flow passage than a comparably sized interflow valve. By doing this, the orifice in the pressure seal and rotor are completely covered during transition thus preventing interflow. Noninterflow valves may be required when precise control of a cylinder is needed and the small settling associated with interflow valves can not be tolerated. Non-interflow valves have a much lower flow rate than interflow valves with the same port size. Mandatory higher force is required to actuate them.