Question 193General Subjects - Assistant Engineer

The correct answer is B) unloading valve. An unloading valve is used in hydraulic systems to temporarily divert some or all of the pump discharge until the additional flow is required. This allows the pump to operate at a reduced load when the system demand is low, which helps conserve energy and prevent excessive heat buildup. The other answer choices are not correct for this scenario. A compound, pressure-relief valve is used to protect the system from overpressure, while a counterbalance valve is used to control the lowering speed of a load, and a sequence valve is used to control the sequence of operation in a multi-function hydraulic system.