Not all pre-configured hydraulic power units can simultaneously meet all design requirements and still fall within applicable constraints. Systems that involve high flow, long duty cycles, or repeated short cycle times often necessitate a custom design in order to function efficiently. Systems that require consistent power at a specific pressure, such as metal processing that involves rolling, typically require a custom HPU. Some HPUs are destined for aggressive work environments that require solutions that pre-configured solutions cannot support, such as in shipyards or offshore oil and gas. In some cases, it may be a matter of where the HPU has to be located relative to key electrical and plumbing fixtures. These are all reasons why custom HPU design is important.

Major Design Considerations for Hydraulic Power Units

There are certain, common design considerations for custom HPUs, starting with the basics such as reservoir capacity and internal design, reservoir type (e.g., vertical or horizontal) overall size and shape, flow range, expected pressures, the number and size of actuators, and portability. Power sources, power consumption, pump type (e.g., standard or internal gear, piston, vane), motor type (e.g., AC or DC electric, air driven, VFD, pneumatically-operated, servo motors), and NFPA or JIC design compliance are also key early on in the design process. In addition, other issues such as filtration, need for cooling, noise constraints, and safety concerns (primarily regarding operators) are important. There are also design constraints for HPU units, such as the location of pumping and power fixtures, available floor space, environmental issues (salt water, extreme dust, extreme ambient temperatures).

Trying to find a pre-configured HPU that meets all the design requirements while still providing efficiency, power, and outstanding performance can be extremely difficult. However, a custom-designed HPU can be built to meet some of the most challenging design specifications you can find — and be designed so that it provides the power, reliability, and performance you need.

Custom Size

One of the benefits of investing in a custom HPU lies in being able to choose the size of reservoir you need even when it is not a standard off-the-shelf specification. Some HPUs simply do not need a large tank, so some designs might require a tank as small as 1 gallon. On the other hand, there are applications where the tank size may easily exceed 1500 gallons. In most cases, the reservoir/tank is the largest part of an HPU. The length of tubing runs or pipes that are required can necessitate a larger reservoir which, in turn, may require a custom solution. Also, keep in mind that pre-configured HPUs for drive requirements of about 100 hp can be very difficult to find. With a custom size, you do not need to settle for something larger or smaller than the capacity you really need.

Custom Shape

Not all HPUs need to have the same shape. While it may be challenging, HPUs can be designed to make the most efficient use of the space available to them while fitting effectively into your hydraulic circuit. It can be difficult, especially when floor space is at a premium, to access plumbing or electrical connectivity. In some cases, an HPU may need to be custom designed to integrate within an existing machine tool space.

Another key factor in custom HPU design is assembling the components so that they all fit well within the exterior framework. Not only is this a good use of space, but it prevents system damage when the HPU is at various stages of its life, including shipment, installation, and daily use. In addition, a custom shape can include a drip edge for containing leaks.

It is also possible to have an L-shaped HPU that provides easy access to hydraulic components for maintenance and repair and has a flooded inlet made possible by having an upright reservoir placed behind the hydraulic components.

Custom Orientation

Another area of customization possible for HPUs is the orientation of the HPU. There are vertical HPUs, often called overhead HPUs, which achieve a minimum footprint while also supporting the steady flow of oil into the pump thanks to a flooded inlet resulting from the reservoir being above the hydraulic components. For example, an HPU that will be used at high elevations (i.e., much higher than sea level) may need to be designed to achieve suction inlet conditions in order to operate efficiently.

On the other hand, there are horizontal, or flat top, HPUs where the reservoir is located below the hydraulic components. This is handy for servicing the HPU, making maintenance easier. However, this type of system may not be as efficient as an overhead HPU because more energy is required to pull the hydraulic fluid up into the pump.

Portability

Another great area of potential when it comes to custom designed HPUs is mobility, the ability to move the HPU where it is needed, or for it to be attached to a machine that is moving. For example, it is not uncommon to see HPUs running the dredge pump attachments on a hydraulic excavator.

Portable HPUs can be configured for use on a wheeled cart or, if needed, vehicle mounted or skid mounted. HPU units can even be designed so that they are remote-controlled, either wireless or wired. You can even have an HPU that can be run from your tablet or smartphone. In addition, these units may be electrically powered or depend on diesel to supply their power.

Challenging Situations

There are times when HPUs are custom designed because of the work environment they will be in. For example, in some situations, floor space may be at a premium so it becomes necessary to design an HPU with dimensional constraints. The design may have to be customized because of the challenges involved in accessing air, power, and/or water.

Ambient conditions may also affect how an HPU is designed, taking into account factors such as maximum operating temperature or expected temperature fluctuations, high humidity, frequent exposure to salt water, or high external pressure for working underwater. For example, if an HPU is going to be used on board a ship or otherwise exposed to salt water spray, it may need some special environmental coating or could be required to comply with marine specifications.

Non-Standard Functions of Custom Hydraulic Power Units

Some HPUs may have to operate at abnormally elevated temperatures, which may require the design of thermal characteristics to keep the HPU temperatures within an acceptable range. Another example of non-standard function might be the use of a HPU where the consumers are located in a ring-like shape where the HPU is central and serves as their main supply. In such cases, a custom design is almost always required. As alluded to earlier, noise can be an issue, necessitating the use of a special sound-dampening enclosure. An even more extreme example are HPUs designed for use in extremely hazardous locations, such as explosion proof HPUs, HPU control panels, and even individual components within the HPU. These would require a custom design in order to meet the requirements involved. Another example is wireless control, which not only provides convenience for the operators but can add an extra level of safety for operators during unit testing or startup.

Special Features

There is an abundance of special features that can be added to a custom HPU, including IIoT (Industrial Internet of Things) to support predictive maintenance, application-specific pain solutions, solenoid or manual control valves, redundant DC backups for AC-powered HPUs, hand pumps, and multi-stage pumps. Applications may involve custom control panels with manual override options. Other HPUs can significantly enhance their performance through the addition of manifolds, cooling fans, or heat exchangers.

Custom Hydraulic Power Units Offer a Host of Benefits

With a custom hydraulic power unit, you do not have to settle for a pre-configured unit that does not really meet the design requirements and constraints established for the HPU unit you need. You can have a custom sized unit that fits perfectly into the limited amount of floor space you have available and you get to choose the shape and orientation, whether it’s a flat top, L-shaped, or overhead configuration. You also have more flexibility when it comes to portability, including how it is powered (electric or diesel) and how it is controlled (remote, wired, wireless). Then there are situations and environments that pose special challenges, such as HPUs for offshore oil rigs, explosion proof designs, or oceanographic applications. And, with custom-designed units, you can include game-changing features that are designed into the system rather than added as an afterthought. With a custom HPU, you can focus on specific aspects such as efficiency, performance, or even environmental impact. Custom hydraulic power units offer many benefits.

MAC Hydraulics — Your Source for Custom HPUs

At MAC Hydraulics, our skilled team can design, manufacture, and build the custom HPU you need at our state of the art facility. And our services do not end there: we also maintain, troubleshoot, and repair HPUs (including those we have not engineered). If you are looking for a high quality, reliable, custom-designed HPU, contact MAC Hydraulics today!