This example shows a test circuit built to check the characteristics of a pilot-operated check valve. The valve is loaded with three ideal pressure sources, two of which create pressure differential across the main flow line, while the third applies pressure to the pilot inlet X. The pilot pressure allows flow through the valve even if the main pressure differential is negative.
The plots below show the behavior of the Pilot-Operated Check Valve block under varying conditions. Flow is permitted from port A to port B (positive flow rate) when the pressure differential exceeds the cracking pressure. Flow is permitted from port B to port A (negative flow rate) when the pressure at port X is high enough to overcome the pressure differential between port B and port A.