HPUs 101


By Supreme Integrated Technology January 16, 2019

At a basic level, an HPU (hydraulic power unit) consists of a prime mover, pump and reservoir. Most HPUs also include a pressure relief valve and a means of filtration, since this may be essential to the safe and efficient operation of the larger system. While some units are multitaskers, most are purpose-built to convert mechanical energy to hydraulic energy. 

Some HPUs may include secondary elements, like integrated pressure gauges, flow meters, heat exchangers, filtration units, pressure and floater level switches and temperature sensors. They may also include shut-off valves or electrical shut-offs. You have probably heard of most of these elements before…but we have recapped a few of their essential roles below:

Prime mover: An electric motor or gas-powered internal combustion engine either converts electricity, or chemical energy, respectively, into rotational mechanical output. The rotational mechanical output of the prime mover is used to turn the drive shaft of a pump, which is typically a gear, vane or piston pump.

Pump: Converts the rotational mechanical power to fluid flow.

Reservoir: Combines source and destination of all fluid flow for a closed hydraulic system. At a basic level, the reservoir’s function is to ensure that a ready supply of fluid is always available to the system.

The actual placement of the reservoir, pump and motor may vary depending on the type of HPU.

Pressure relief valve: An essential safety device that limits maximum pressure of the system. When pressure exceeds the relief valve setting, the pressure relief valve opens, allowing an alternative path back to the tank.

Filter: Similar to a net, it removes contaminants from the larger system allowing cleaner liquids to pass.

Pressure gauges: Indicates pressure at a specific point within a hydraulic system.

Flow meter: Used to visually indicate the flow rate/basic hydraulic performance data for operators.

Heat exchangers: Used to condition fluid operating in extreme environmental conditions (Heater/cooler, depending on circumstances).

Offline/kidney loop filtration units: Filters fluid directly from the reservoir and back. A kidney loop filter is an isolated subsystem tasked solely with fluid maintenance that requires a small pump to drive the circuit.

An HPU is basically everything you need to run a hydraulic system. There are many additional elements that may, or may not, be required in your HPU.

Supreme Integrated Technology offers many different configurations of HPUs from the smallest to the largest of applications. Contact us today to start working on your next HPU project!

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