Get in touch today to discuss your requirements
Call: (+44) 01452 523352
We’ve always been a fan of predictive maintenance for hydraulic systems. It can save time, system damage, expense and downtime. If it’s not already embedded into your workshop processes, then we recommend that predictive maintenance is put right in there along with your inspection processes.
In this post we look at the categories that John Moubray uses in his Reliability Centred Maintenance II book to understand how predictive reasoning should be approached. This is then followed by an example of how it could be used to understand what’s happening with your hydraulic system by using your powers of reasoning.
Broken into these 6 major categories, these maintenance actions can save you expense, time and of course loss of productivity through downtime. What any engineer who works with hydraulic systems should focus on are:
1. Dynamic effects including the monitoring of vibration, pulses and acoustic emissions.
2. Particle effects including the monitoring of particles in the operating environments of the component – ie the condition of the lubricant.
3. Chemical effects: monitoring of the chemical elements in the components operating
4. Physical effects such as cracks, wear, fatigue
5. Effect of temperature
6. Effects of electrical
Although Moubray’s list does cover most of the hydraulic systems maintenance needs, it does not cover all and there are new techniques being discovered and devised continually that should be researched. The visual inspection is one of the most basic and necessary of all predictive maintenance techniques.
Putting this to the forefront, it’s important to look for the following during a hydraulic system inspection:
· Both the quantity and the quality of the hydraulic oil in the tank needs to be checked. The appearance should be bright and clear.
· Check for any leaks or weeps around the seals, connectors and component bodies.
· The surface condition of the tubes, pipes and hoses external.
· The cylinder rod-wiper seal condition needs to be checked.
· The cylinder rod surface. Look for scores, nicks and dents.
· The filter clogging indicator position.
· The readings of the operating pressure (test-points and gauges that have been permanently installed should be used)
· The operating temperature of oil (use either an installed thermocouple or a heat gun)
· Listen out for abnormal noises such as knocking and clicking
The success of predictive maintenance tasks depends on whether data is recorded and then how it is analysed, whether it’s collected through human senses or by using sophisticated measuring tools. It is then necessary to take actions that will either remedy the situation or avoid damage from occurring. The process for predictive maintenance is this:
· Data collection
· Analysis of data
· Predictive reasoning to ascertain possible future issues if maintenance is not addressed
As an example, you may prefer to perform an inspection of your system as part of your regular maintenance routine. You may discover that there is a noise that has increased in volume and that there is no longer a smooth cylinder movement with your actuator. There could be an interpretation of this even as there being issues with reliability and performance of the system up ahead including issues with lubricity. These are all issues to record and take note of for future analysis.
In addition it’s necessary to ensure that the interpretation of the data is in the right context. Perhaps your visual inspection reveals an issue with the filter being clogged. You may identify this from the clogging indicator. Although this would not normally be an issue, it is if the last time the filter element was cleaned or changed was just the day before. Although the data is the same, used through the filter of a different context, then your reasoning will be entirely different.
Summary. It’s important to identify issues in hydraulic systems so that action can be taken whilst the issue is still small. Predictive engineering offers this solution. It also makes it possible to refine your system so that you can avoid issues and enable your machine to have less downtime and expense. It’s truly worth getting into the routine of looking for issues early on.
Our engineers are focused on producing mobile hydraulic power packs. We provide insights into hydraulic system maintenance for those who have an interest. If you’re looking for a custom solution to your hydraulic system application needs, contact us today.
When you work with hydraulics every day it is easy to take the technology for granted, especially when you know how it works and for what purposes. However, most hydraulic engineers focus on a specific application of the mechanisms and may not realise that there are other uses for the technology that we use every day. For example, petrol pumps use hydraulics to draw the fuel up from the reservoir and deliver it into your vehicle. When you draw up to the pump you make use of hydraulics to stop the car; most vehicle braking systems use hydraulic action to exert force on the brake discs. Hydraulics then allow you to fill the car up, and drive away, using your brakes several times on the journey home.
If you go to any large shopping centre or office there are lifts, which can make use of hydraulics to raise and lower the elevator car. Some older lifts still use a pulley system, but many newer systems use hydraulics. The sandwiches you have for lunch also rely on hydraulics to exist; the mechanisms in large bakeries use this technology to move conveyor belts and other large scale mixing machines to keep the dough moving along the production line. If you sit at an office chair while eating lunch you are also making use of hydraulics, as the mechanism that allows you to lower and raise the seat is usually a hydraulic one.
Visiting the dentist also involves hydraulics at least once, more if you drive there and fill the car up on the way! Dentist chairs use hydraulic pumps to lower and raise the body of the chair as well as to adjust the angle of the foot rest and head rest. Hospital beds and barbers chairs work on the same principle. Vehicle mechanics use hydraulic lifts to raise vehicles up for inspection and repair work in much the same way.
Hydraulics also make an appearance in entertainment; theatre stages that can be raised and lowered use hydraulic systems to make this happen, and similarly, theme parks rides use them to create and control motion. On arriving home from a day out at the theatre or a theme park you may drive your car into a garage with a hydraulically operated opening mechanism, or through a gate that employs the same technology to open and close at the touch of a button. Once in the house you may have to load the dishwasher and set it to run; even here there are hydraulics at work to improve water pressure for better cleaning. Hydraulics are found in many aspects of everyday life that it is possible to make use of six or seven different applications in a single day.
Hydraulic engineers and designers have long been facing uncertainty over the future of hydraulic power in an increasingly electrified world. The replacement of hydraulics with electrical actuators and components in vehicles especially has caused unease over whether hydraulics truly has a place in effecting motion as technology marches forward. With the introduction of the Internet of Things (IoT), a truly connected network of equipment, household appliances and even lighting or heating systems, hydraulic power seems outdated, and likely to be replaced by electric alternatives as the technology improves unless the new generation of designers embrace the benefits of hydraulic power.
Hydraulics still has many clear advantages over electric power; load bearing capabilities and predictive maintenance are just two of the benefits of using hydraulic power and easier troubleshooting and repair underline the plus points of hydraulic versus electrical power. It is obvious, however, that for hydraulic power to survive and compete it must integrate seamlessly into electrical circuits so that there is no reason not to choose a hydraulic component over an electrical one, solely on the basis of ease of integration into the rest of the system. Many hydraulic power packs now, including the ones produced by Hydraproducts, are designed to fit with electrical circuits and to be used with electrical power, translating a small amount of electrical power into a much larger hydraulic force, without any risks of high voltage electrocution or shorting out a circuit under increasing loads.
One of the most understandable facets of the IoT is the unmanned warehouse. Already in trial by Amazon (using drones) and some Chinese companies (using robots running on a grid matrix), these automated warehouses need minimal human staff, with even deliveries being accepted by robots using RFID tags. The central processing office can oversee the delivery, but no one needs to physically sign for a consignment as this can all be done through sensors. Moving new stock to the right location within the warehouse is done through robotics, and the incorporation of electrohydraulic components means even heavy items can be moved and lifted into place on shelves. Sensors ensure that the location of each item is logged, and this data can be used to create an automated picking list for the same electrohydraulic robots to compile an order. Electric actuators may be used for warehouses that only deal in lightweight stock, but for car parts warehouses and other stockists of heavy components the extra power that hydraulic components offer is essential for true automation.
If nothing else makes hydraulic components an attractive choice, then the ability to scale up power and force through the intelligent use of hydraulic power certainly does. Electric alternatives may be getting cheaper and are undoubtedly easier to wire into a circuit than traditional hydraulic units, but the marriage between electric and hydraulic power makes perfect sense for fully capable robots that can cope with lifting and transporting items of all sizes and weights. The replacement and maintenance involved with fully electric systems is comparable to that of an electrohydraulic system, but it can be much harder to pinpoint the exact cause of a problem without careful study of the wiring schematic and an understanding of the original design. Hydraulic components, by comparison, are easier to fix for those who were not involved in the design process and given that engineers and maintenance people generally are not involved in the specification of a system, it is intelligent to have a system that can be fixed more easily.
The IoT is not confined to commercial and industrial applications, however, and in part 2 we look at the uses in the smart home.
The development of modern hydraulics arguably echoes the development of modern industry. During the industrial revolution, factories worked largely on brawn with images from the period showing steam-belching machines operated by hard-working labourers. Today, the focus of industry is on working smarter rather than just applying muscle power. Part of the reason for this is that the nature of the products being made has changed. Factories today manufacture technologies that previous generations could barely have imagined. Margins are as thin as silicon wafers and any error can have significant financial consequences. Similar comments apply to other hydraulics strongholds such as construction.
While hydraulics on its own may lack the precision needed for a modern industrial environment, when it is coupled with advanced electronics, industry can have the best of both worlds. One of the reasons why hydraulics has been appreciated for centuries is because its lifting power is smooth. When partnered with digital electronic sensors capable of undertaking thousands of measurements a second, hydraulic systems can be refined to a very high degree of precision. Another reason for the longevity of hydraulics is the fact that the essentially simple mechanics behind the technology makes for a high degree of reliability. Given that reducing variability in manufacturing (and other areas) has been a major preoccupation for industry since the invention of Six Sigma in the mid 1980s any technology noted for its consistency already has a strong point in its favour.
These new enhanced hydraulic systems are moving into unexpected places. The same technology that powers heavy-lifting equipment and automotive systems may soon be finding its way into the human body. Researchers at the University of Minnesota are working on a project to create orthotics using hydraulics. As the body ages (or as the results of sporting activity or accidents), joints are often the places where the effects of wear and tear begins to show first. The idea of using hydraulics to replace knee and ankle joints has obvious benefits given the loads carried by them even during day-to-day activity. As the technology develops, it may well become small enough for tiny joints such as knuckles, worn out by excessive keyboard use. They estimate that the technology will be a reality in anything between 10 and 20 years from now.
It’s no secret to hydraulic system engineers that implementing proactive maintenance takes both time and money. It’s for this reason that it’s important to get a grip on whether the tasks involved are worthwhile in terms of return on investment as part of the ongoing engineer’s challenge of increasing reliability.
Here at Hydraproducts we have debated this subject matter at great length and we have settled on using the Reliably-centred Maintenance (RCM) approach with a set of questions to understand more with regards to our maintenance investment decision making. The questions are:
· Is the machine acceptably reliable?
· How critical is it that the machine is operating fully?
· Will improving the maintenance of the machine prove to be a cost effective exercise?
· Is it worth investing in redesign of the machine to improve reliability?
· Is the machine and its components expendable and if so, should it be run into the ground?
RCM has now been established in many engineering practices, but it’s most prominent in the airline field. Performing extensive maintenance on all the systems of a large airliner would not make sense as it would result in the aircraft spending more time in the hangar than it would in the skies making revenue.
However, it’s critical to have a safe airliner and therefore, the maintenance process must not compromise safety in the resulting reliability.
Although there are a lot of questions that are more ‘what if’ by nature, they can help to ensure that the right maintenance gets performed, giving the best possible results.
Running through the RCM process on any complex hydraulic system can be both time-consuming and arduous. It’s a system that is most effective when performed on a fairly new machine with unknown failure causes. In summary, being able to detect problems early and therefore be able to extend the life of a hydraulic machine can save time, money and downtime. As engineers it’s our role to find a way to detect these problems and on some occasions, an RCM type approach can prove to be a valuable aid.
Subsea hydraulics is a very niche area in the world of hydraulics engineering. It’s an area that is mostly focused in the oil and gas industry (90%), 9% in military and 1% in other. It encompasses seafloor systems, surface control equipment and the control of oil wells amongst other tasks such as cable maintenance and seabed exploration.
The Role of the Subsea Hydraulics Engineer
Subsea hydraulics engineers have some seriously interesting challenges to solve. Not only are they faced with the day to day hydraulic challenges that most of us deal with, but they also have to handle the sea, its power and pressure. The pressure found on the seafloor is extreme. What’s even more extreme is the pressure found inside the wellbores for underwater energy extraction.
One of the biggest challenges for these engineers is the development of Blowout Preventers (BOPs) that are used to contain oil. It’s what prevents oil from emerging into the ocean and creating a giant spill that results in a wildlife emergency. This can prove to be very costly for oil companies.
BOPs have to be designed, tested and operated in addition to having procedures written and processes established. Subsea hydraulic engineers also handle other equipment such as the subsea robots that are also known as Remote Operated Vehicles (ROVs). ROVs need to be winched into and out of the water using hydraulic power at the winch. In fact, you may find some of our hydraulic power units in use at winches.
Developing a deep water oil field requires an astonishing amount of equipment. Although there are some electric systems used, the controls are typically managed with hydraulics. The field could be giant and cover miles from one side to the other.
Oil Fields can be miles across...
...and involve large amounts of subsea equipment. The job of the subsea hydraulics engineer is to ensure that all equipment is working the way it should be. There are calculations to do, designs to create in addition to plenty of operating procedure and process writing and revising. There’s also a requirement to develop a schematic of how each piece of equipment sourced from different vendors is going to operate and interface on the sea floor. This takes a lot of PowerPoint and Excel use to map this out for the other employees and management!
The Subsea Hydraulics Engineer Prevents Disasters
A major part of the role is to do the small day to day things that go a long way in preventing anything exciting from happening. We don’t want to have to get involved in issues such as needing to perform an oil spill recovery. In this industry, even the smallest mistakes can cause disasters that poison marine wildlife, sink expensive equipment or even kill people. It’s something that we take very seriously.
Some hydraulic engineers in other companies do tasks such as design remotely operated vehicles (ROVs) and launch and rescue systems (LARS) for use by the oil and gas industry, movie makers, the navy, explorers, scientists and even treasure hunters.
Hydraproducts has customers in a broad range of industries, including in the subsea fields. We supply hydraulic power units from micro size to bespoke size to suit whatever is required in all industries, including marine related.
Preventive Maintenance for Hydraulic Pump System
When it comes to preventative maintenance for hydraulic pumps, it’s essential to be aware of the critical part that the hydrostatic drive system plays. This is also known as the hydraulic pump system. This system comprises piping, valves and filters and is what controls the entire system.
Part of this system and what drives the machinery is the hydraulic motor or hydraulic cylinder. The hydraulic pump is the generator of power and the good running of this is what ensures the pressure is correct.
A hydraulic pump works in either a hydrostatic or hydrodynamic system. The former determines the pressure of stationary fluids, whilst the latter is what forces the liquid and will often result in the movement of the hydraulic machinery. The quality of the pump will depend upon what flow and pressure is required, in addition to the lifespan and its effectiveness.
When it comes to performing preventative maintenance of a hydraulic pump, it’s important to schedule this as a regular activity. Its success will depend upon a disciplined approach. It must also be related to performance so that any changes in performance are monitored and then action taken based on those results.
Considerations that you’ll need to keep in mind are:
· How often is the system operating? Is it full time or only periodically? Is the operating environment dirty and hot? You should also check the manual or instructions supplied by the manufacturer to understand what their recommended operating parameters and preventative maintenance are for the machinery.
· Check the filter and whether its predicted lifespan fits with your preventative maintenance plan. You should also check the history of the equipment and how often it has been serviced or undergone maintenance.
· As in all PM plans, there must be procedures written for each maintenance task. These actions must be written in a way that is very clear and not open to be misconstrued by maintenance personnel at all levels.
Hydraulic Power Pack
Connect with us
Connect with us on social media or eBay