Smaller Footprint: Extend the Life of Hydraulics
By Rehana Begg
Energy efficient components and training initiatives can help maintain hydraulic systems.
October 26, 2020
By Rehana Begg
Scarcity of resources and the impact of climate change is a megatrend that drives the need to shape responsible attitudes to protecting our natural resources. This lynchpin behind the growing emphasis on energy efficiency and sustainable technologies challenges manufacturers to step away from a take-make-waste extractive industrial model in favour of a circular economy approach, which aspires to decouple from consuming finite resources while designing waste and pollution out of the system.
The phrase “reuse, prevent and repair” is unambiguously associated with environmental efficiency, but could serve as a mantra for a conscientious aftermarket Typically, the opportunities to save energy and reduce operating costs across industrial MRO markets are tied to overall energy consumption at the plant or on the shop floor. The choice to be intentional about energy efficiency and cost savings begins with selecting equipment and components that take advantage of various energy sources, while limiting the waste associated with the processes that transform that energy.
Take modern hydraulic systems for example. A hydraulically powered machine using “smart” and energy-efficient components (including valves, seals, filters) not only reduces the damaging effects of fluid friction, but also creates value and rapid ROI (return on investment), argues Aaron Weston, hydraulics specialist and owner, ASW Enterprises in Stratford, Ont.
Weston highlights research on global applications of electric motors in industrial settings that shows that about 60 per cent of electrical power generated is consumed by electric motors. This consideration throws light on increased production costs and pollution and motivates industry to optimize energy efficiency.
Fixed displacement pumps, for example, waste energy by either dumping over a relief valve or bypassing fluid when pressure exceeds its setting.
“That is wasted energy,” said Weston. “If you’re driving these pumps at 1,800 rpm, that’s hydraulic horsepower that’s not being utilized. It’s turned into heat energy. If you can lower the rpm, you can reduce the heat energy and reduce the waste.”
Weston, who researches market technologies, cites Bosch Rexroth’s Sytronix as just one example where variable frequency drive (VFD) servo motors are being used.
“Instead of having motors run and pumps compensating and wasting energy, they’re starting to lower the rpm and react to the demand of the system,” said Weston. “So, there’s been significant downsizing in the hydraulics; the load has been brought down.”
In an interview with Machinery and Equipment MRO, Weston acknowledges the extent to which electrification has impacted a mature hydraulics industry.
“You can say it’s negative and that servo and electrical components are more capable with higher forces, but you’re always going to need hydraulics for highforce outputs,” said Weston.
“Hydraulics is its own animal” and demand endures for technical knowledge on hydraulic systems and for innovative ways to lower its footprint, suggests Weston, who delivers courses ranging from Principles of Hydraulics and Maintenance, Repair & Commissioning of Hydraulic Systems, to Piston Pumps & Motor Controls, Servo & Proportional Hydraulics, Design Considerations, and Mobile Hydraulic Systems.
Currently supporting Bosch Rexroth Canada with hydraulics instruction at sites across Canada, Weston also points out there are few colleges in Canada that offer training for hydraulic specialists.
“Centennial College used to offer courses and Mohawk College has a little bit, but it’s just not focused enough. As a result, aftermarket companies like Rexroth or Vickers or Parker or Siemens have to do training, because nobody specializes and there is no special field for it per se in the educational system.”
MRO: How are best practices evolving across the hydraulics industry and its aftermarket as enterprises strive for more sustainable practices?
AARON WESTON: Electrification is here, and with respect to the hydraulics industry and its aftermarket, more and more hydraulics companies are developing and implementing hydraulic systems utilizing variable frequency drives and servo motors. Having variability with the prime mover (the VFD motor or servo motor) now means less complication with the hydraulic pump.
Therefore, depending on the pressure/force requirements, the hydraulic pump used can now be a less expensive vane or gear pump. This does put a bit more expense on the electric motor and control side. However, this has been the direction companies who build air compressors and water supply systems have moved over the past 20 years.
From a sustainability standpoint, both knowledge and aftermarket components for the electrical side of the control are more widespread. From an energy perspective, there is a lot less kilowatt usage, because during idling and when holding pressure, the prime mover (motor) can slow down to 200 to 300 rpm. When flow is required the prime mover can speed up rapidly to 1800 to 2200 rpm. This presents significant energy savings.
MRO: Hydraulic pumps and motors were traditionally designed to be workhorses for mobile machinery, particularly in combination with diesel engines. These days, manufacturers look for energy efficiency solutions through electrification. Can you elaborate on how the trend towards electrification impacts hydraulics? What kinds of efficiencies do we gain and what do we lose?
WESTON: The overall advantage of electrical energy is that it is less wasteful than hydraulic energy. The law of energy simply states you can neither create nor destroy the energy, only change its form. With hydraulic energy, if something is not being moved, either linear or rotary, or a combination of both, there is waste, and that wasted energy is transferred to heat energy.
With the ability to control the electrical energy, utilizing only the power required to do the work, efficiency solutions through electrification have become the trend. With that said, this means less use for linear and rotary solutions with hydraulics if electrical solutions can perform the work at a cost-competitive advantage.
MRO: The hydraulics assembly process can generate a variety of waste materials, such as scrap hose and couplings, and other rubber and plastic materials. From field experience and observation, can you provide examples of waste? What should be the approach to handling waste or leakage at the plant level?
WESTON: With respect to old hoses, damaged pumps, and discarded components, I believe the industry does a good job with recycling materials, considering much of the material recycled is steel, brass or bronze and rubber, which often yield a decent return when recycled.
With respect to oil leaks, and leakage, not a lot is done overall to repair or prevent leaks. Many companies are under tremendous constraints to produce their products and often the cost of replacing the oil, unfortunately is easier than allowing the downtime required to find and repair leaks.
MRO: Can you provide a few pointers on how industrial plants can optimize MRO strategies in support of sustainability?
WESTON: Really invest, utilize and believe in reliability centred maintenance. With the advent of Industry 4.0, and the Internet of Things (IoT gateways), so much has been developed to signal to industry the health of their hydraulic systems and all the components involved. Thermal imaging technology is cost-effective, and with heat signatures prevalent in hydraulic systems, heat signatures can tell an end-user a lot about how their system is operating, often indicating when components are headed to failure mode.
Oil analysis, vibration analysis, pressure values, flow values, positional information, among many other inputs, can give very important information before critical failures arise, and the cost of these systems has become favourable in recent years.
MRO: Arguably, addressing some of the sustainability issues requires a deep understanding of basic processes in fluid mechanics, heat and mass transfer and materials science, and more. What role should hydraulics instruction play in educating industry on sustainable best practices? Are there any standards to reference? What is your personal approach to instruction?
WESTON: Unfortunately, hydraulics instruction is not covered with any great deal of detail at either the college or university level. In-depth knowledge required to address some of the sustainability issues is lacking in the industry because of the lack of understanding of basic fluid principles. Hydraulics instruction, beyond the college and university level, has become crucial for those who design, build, install and service hydraulic systems—especially with the marriage of electrical systems into hydraulic systems, that is, electro-hydraulics.
My personal approach to instruction, first and foremost, is safety. Hydraulic technology is a very dangerous technology with system pressures sometimes registering well over 5,000 psi (350 bar). Beyond that, understanding the basic fundamentals of fluid power (energy, horsepower, heat, torque, pressure, flow, etcetera), understanding the inputs (pumps), understanding the outputs (actuators—motors and cylinders), and understanding all of the controls in between (pressure control, flow control, directional control). MRO
Rehana Begg is a Toronto-based freelance editor.She spent the past decade in the trenches of industrial manufacturing, focusing on engineering, operations, asset performance and management. Her B2B journalism career has taken her from corporate boardrooms and plant floors to underground mining stopes, covering everything from IIoT/software and continuous improvement and maintenance best practices in industrial plants, to MRO for the automotive and food and beverage industries. She is the former editor of CanadianManufacturing.com, CleanTech Canada, Machinery and Equipment MRO, Resource Engineering and Maintenance (REM) and Plant Engineering and Maintenance (PEM) magazines at Annex Business Media. Rehana holds a master’s degree in journalism and an MBA in project management. Reach her at firstname.lastname@example.org.