Relief Unloading Valves

Pressure Control to Eliminate Excess Fluid

Unload When Critical Pressure Has Been Reached

Marotta’s Relief Unloading Valves are pressure-control devices that are used to dump excess fluid when the line pressure reaches a pre-set value. A typical application is for the Helicopter In-Flight Refueling System (HIFR). Once the fuel tank is full the Relief Unloading Valve will open returning additional fuel back to the sump tank.

Relief Unloading Valves are primarily used in hydraulic circuits, accumulators where a pressure regulator is required to automatically unload the pump when the pressure reaches the pre-adjusted pressure setting of the valve.When the pressure has dropped to approximately 85% of the valve setting, the valve poppet closes, thus diverting the pump delivery to the system.

NOTE: The listed performance data may represent specific program requirements and not the design limitations of the technology.