Hydraulic Power Units
Hydraulic power units:
Apply the pressure that drives motors, cylinders, and other complementary parts of a hydraulic system. Unlike standard pumps, these power units use multi-stage pressurization networks to move fluid, and they often incorporate temperature control devices. The mechanical characteristics and specifications of a hydraulic power unit dictate the type of projects for which it can be effective.
Some of the important factors that influence a hydraulic power unit’s performance are pressure limits, power capacity, and reservoir volume. In addition, its physical characteristics, including size, power supply, and pumping strength are also significant considerations.
When a hydraulic power unit begins functioning, the gear pump pulls hydraulic fluid out of the tank and moves it into an accumulator. This process continues until the pressure within the accumulator reaches a predetermined level, at which point a charging valve switches the pumping action to begin circulating fluid. This causes the pump to release fluid through a charging valve back into the tank at minimal pressure. A special one-way valve keeps fluid from flowing out of the accumulator, but if the pressure drops by a significant amount, the charging valve reactivates, and the accumulator is refilled with fluid. Farther down the line, a reduced-pressure valve regulates the flow of oil moving to the actuators.
If the fluid in the system begins to overheat, a temperature switch can shut the motor-pump off, and a level sensor signal to refill the tank if its fluid level is too low or shut down the system due to a leak.