A hydraulic power unit is an arrangement of components, which is used to control hydraulic energy. Mainly comprised of a motor, pump and reservoir, it is amazing what can be achieved. Hydraulic systems are used in any form of mechanical devise to push, pull or lift. The primary components required to achieve this are discussed below.
Power Source
The power source is a combination of three required elements
- Motor – AC or DC or Internal combustion engine
- Hydraulic Pump – Common types gear, piston or vane
- Reservoir – Holding tank for hydraulic media
- Filtration – Commonly a strainer for pump inlet, pressure filter for pump outlet, and/or return line filter
These components determine flow and pressure limits of your hydraulic system. Pumps produce flow and are designed to do this at a pressure that restrictions within the system allow. These are primarily based on their suitability to produce flow, pressure, efficiency and noise level. The reservoir is the storage vessel for the hydraulic oil, which holds an appropriate amount of oil to operate the hydraulic system components, designed to dissipate heat and help maintain the best possible condition with the use of sight indicators, filler breathers, inspection covers, level switches and drain ports. Filtration is a critical part of a hydraulic power units, ensuring wear is minimised and efficiencies are maintained. Suction strainers capture the largest of contaminants and ensure they do not enter the pump. Pressure filters are selected when highly filtered oil is required within the hydraulic system. Contamination within the system is filtered out by the return line filter before it enters the hydraulic reservoir.
(Question to ask in future posting, whether pressure line filters should be used on all hydraulic systems)
Control Valves
There are many different types of control valves used in many different ways. Pressure control valves limit or control the hydraulic pressure within the hydraulic system. Directional control valves direct the flow of oil around the system and are controlled manually, electrically, hydraulically or pneumatically. These valves are used in separately or combination to gain the desired function of actuators, motors and other components.
Modern day applications of hydraulic power units are extremely diverse and divided into mobile applications (agricultural machinery, diggers, graders, road maintenance vehicles, forklifts, excavators, etc.), industrial applications (machine tools, food processing machinery, automatic handling and assembling equipment, steel works and mining, etc.), and other (automotive, aerospace, marine, medical, leisure, etc.)
