Hydraulic power packs and mini power packs

The hydraulic power units are the heart of every system, because they are the point where the mechanical energy produced by the engine is transformed into hydraulic power.

Hydraulic power packs and units are sometimes also called HPUs (Hydraulic Power Units).

They are used to transform electrical energy into mechanical energy.

They are part of the hydraulic systems where, on principle, the force is transmitted by a fluid contained in a tank. The fluid is sucked in by a pump and sent through the distribution and adjustment organs to activate the actuator to perform a certain work.
The actuator must overcome the resistance offered by the load and therefore requires to the hydraulic fluid a proportional pressure to this resistance.

Appropriate regulating valves allow the pump to deliver the fluid at the required speed and to adjust the pressure according to the load requirements. When the fluid has finished its function it returns to the tank, to be sucked in again by the pump.
The hydraulic fluid is almost incompressible and can therefore transmit considerable forces, it is easily adjustable and therefore suitable for solving numerous cativation problems.

It can therefore be understood that the pressure is not generated by the pump, but rather by the load which opposes the passage of the fluid: if there were no resistance, the fluid could flow freely and the pressure would become zero.

The hydraulic power unit, or control unit,is a truly independent system which generally includes a motor, a tank, fluid, a distribution group (valves) and a pump which works to apply the hydraulic pressure and a certain flow rate, necessary to drive motors, cylinders and other complementary parts of a hydraulic system.

The main components are therefore:

• Tank, to store the fluid, with relative cover
• tank filler and draining cap
• submerged pump, to convert mechanical power into hydraulic power
• cylinders or motors, to convert hydraulic power into mechanical power
• valves to control pressure, direction and quantity of fluid
• suction, delivery and discharge filters (also called return filters), which allow the condition of the fluid to be kept “free from contamination” (*)
• flexible pipes, rigid pipes and fittings, taps
• accumulators, to store energy (bag, piston, etc.)
• elastic joint and lantern to protects the joint
  heat exchanger
• Instruments to monitor the performance of the hydraulic unit such as pressure gauges, oil level indicators, pressure transducers, thermostats

(*) We wish to emphasize that there are some essential aspects which allow the hydraulic system to provide the best performance, the highest reliability and the longest life.

One of them is the fluid management:the hydraulic system can provide the best performance, the highest reliability and the longest life, only if the fluid is filtered in order to remove foreign solid particles,and cooled (or heated) to keep the temperature excursions within limits compatible with the viscosity and duration required of the fluid.

These functions are performed separately by specific equipment, respectively filters and heat exchangers, and simultaneously by the tank, the correct execution of which therefore assumes fundamental importance.