What Are Hydraulic Power Units (HPUs)?

Almost every hydraulic system is run by a hydraulic power unit (also referred to as a hydraulic power pack). Hydraulic power units are self-contained systems that are generally built for the single task of converting mechanical energy into hydraulic energy. They work by applying the hydraulic flow and pressure required to drive motors, cylinders and other complementary parts in a hydraulic system.

Hydraulic power units can range in size from 0.2 to 1000’s of kW. HPUs can be used in a vast array of industrial sectors, including offshore, oil & gas, commercial vehicle, production lines, agriculture to name a few. Hydraulic power units can generate huge amounts of power to drive hydraulic machinery.

What Are Hydraulic Power Units (HPUs)? guide illustration 1

What Is the Difference Between a Hydraulic Power Unit and a Hydraulic Power Pack?

There is essentially no difference between a hydraulic power unit and a hydraulic power pack. The two terms are interchangeable.

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How Does a Hydraulic Power Pack Work?

The hydraulic power unit provides the power required for the transfer of fluid in a hydraulic system. However, hydraulic power units are different to standard hydraulic pumps due to a multi-stage pressurisation network used to move fluid. During the operation of a hydraulic power unit the hydraulic fluid flows out of the tank into the pump and is directed  into the system. 

There are a number of areas that affect a hydraulic power unit’s performance, such as its size, power supply, pressure limits, power capacity and reservoir volume.

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Components of a Hydraulic Power

To have a clearer understanding of the operating principles of a hydraulic power unit it makes sense to investigate a standard model’s basic design components. Depending on the size of the hydraulic power unit and its application determines its design. We have listed the most common standard hydraulic components involved below.

Hydraulic Motor Pumps

Hydraulic motor pumps are attached either singularly or in multiples to the hydraulic power unit. 

Tank Storage

Tanks are designed with adequate hydraulic fluid volume to support the systems total requitements, dissipate adequate heat and allow air to separate from the fluid. 

Filter Units

Filters provide a means of removing contamination from the hydraulic fluid. The hydraulic systems reliability, performance and life expectancy is extended considerably by maintaining a low contaminant level. Filter elements should be changed on a regular basis or in accordance to the clogging indicators. Some filter elements are more efficient than others and this need to be carefully considered.

Coolers & Heaters

Hydraulic systems need to have a temperature regulation process. Ideally the system is designed with optimum efficiency and colling is not required however some systems require additional cooling and air or water coolers can be installed. Heating systems can provide the opposite and increase temperatures when required in cold climates.

Pressure Control Valve

Hydraulic power packs normally have a pressure relief valve that prevent over pressurisation of the hydraulic system. Depending on the application and selected components pressure relief valves limit the maximum pressure by opening and passing fluid to tank.

Directional Control Valve

Directional control valves are used to switch the direction of oil flow within service lines, allowing a his allows a change in the direction of actuators. 

Hydraulic Accumulators

Hydraulic accumulators are energy storage devices that hold hydraulic fluid and a compressible gas (generally nitrogen), separated by a bladder or sealed piston. The stored energy can be released at critical points through machine cycles to provide a burst of flow above that of the pump.

Electronic Controllers

Some hydraulic systems benefit from electronic control providing an element of logic and machine optimisation. Electronic controllers provide an operating interface controlling items such as switches, displays, input devices including analogue sensors along with monitoring features. 

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How Much Power Is Generated By A Hydraulic Power Pack?

The hydraulic power generation is determined by the prime mover. Desired flow multiplied by the maximum pressure equates to the power demand. System design and appropriate product selection determine the efficiency and ultimate performance of the hydraulic system. The better the design the less noise, less heat and less wasted energy results.

Hydraulic systems are based on Pascal’s Law of Physics, in that they get their power from ratios of areas and pressure. So, in theory, lifting or turning force can be multiplied with relative ease by adjusting the size of active area. 

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Where Can You Find Hydraulic Power Units Being Used?

Our HPUs range in power from 0.5 kW up to 500 kW with a pressure capability of 100’s of bars and flows ranging from single digits into thousands of litres per minute. Our HPUs are carefully engineered for high levels of system efficiency, are low noise, energy efficient and highly reliable. We supply hydraulic power units to a vast array of industries for uses in a multitude of applications.

Mobile Hydraulics

For use in construction equipment, military machines, railways and mining.

Industrial Hydraulics

Our hydraulic power units are used in industrial applications including process machinery, printing and presses.

Hydraulics in Aviation

You can see our hydraulic components being used to good effect in aircraft support.

Agriculture Environment Hydraulics

Ground care, harvesting and forestry are just a few of the areas that make use of hydraulic power units.

Hydraulics in Waste Recycling

Our energy efficient and reliable hydraulic power units are used across many applications within the waste and recycling industry.

Posted by admin in category Hydraulic Systems Advice on Wednesday, 27th July 2022

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