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The street sweeper is a ubiquitous sight in cities across the country; once the preserve of Trigger et al, the humble broom was replaced by the compact mechanical sweeper which removes debris and dust from the streets using air, water and rotating brushes. Low pressure water jets spray ahead of the brushes to damp down the dust, thereby stopping it from rising into the air too much. The rotating brushes pick up the debris and it is collected into a hopper for emptying later on. Although harder to fix than a broom, which may only require a new head or a new handle, they are much more efficient at quickly cleaning streets and come into their own after events such as the Notting Hill Carnival or London Marathon.
The machines we see on the streets are designed specifically for the purpose of street cleaning, but there are also other locations where sweepers are used, such as on construction sites, at mines and even at waste processing and recycling facilities. At these locations, the sweeper normally takes the form of an attachment that can be fixed to a front-end loader or other hydraulic machine. This is done for cost and efficiency reasons, as it removes the need for a separate vehicle and allows an existing one to be used in a different way. These attachments use the auxiliary hydraulics of the machine to which they are fixed to provide power for the brushes, water sprayers and positioning system of the attachment. They too have used low pressure water jets up until now, but the drawback is that the reach of these jets is small, and because the water is concentrated on a relatively small area, it can end up creating a muddy paste which is then smeared on the surface rather than being cleaned up, and the dusty particles that do not get watered are then kicked up into the air to settle elsewhere.
Dynaset Oy have found a solution to this problem by using the hydraulics in sweeping attachments to power a hydraulically operated water intensifier. This addition pressurises the water creating a fine mist that contacts more of the dusty dirt without forming a paste. The system also uses far less water than a conventional sweeper attachment, so is better for the environment in that sense as well. The HPW Dust component can be fitted to any hydraulically powered machine that uses water, so can be used for pressure washing and other purposes that require high pressured water. It uses the power of the hydraulics to create the high pressure and does not need any additional power or electronics to work.
The resulting cleaning is much more effective; the water is still sprayed ahead of the brushes but damps down the dust more effectively, so the brushes can clean properly without sending that dust up into the air. The air quality post sweeping is visibly cleaner and this is important in routinely dusty environment such as mines and construction or demolition sites, especially if these are located in built up areas, where there is already an environmental concern over air quality.
This technology is not being used in city street sweepers yet, but it could make a very real difference to the air quality in urban areas if deployed in these machines. There is some development to do in order to make the water intensifier technology work in modern street sweepers as they are not hydraulically powered, but when designing new models hydraulic power could be an option to operate not only the high-pressure water delivery, but the brushes and collection method as well.
The reduction in the amount of water used, coupled with the superior cleaning could be incredibly useful in developing countries or very hot climates where water is at a premium. The applications of this hydraulically operated water intensifying system are numerous and will become apparent as the technology is deployed in other hydraulic machinery, or integrated into new designs of current machinery. Perhaps the most obvious application for this invention is the automatic car wash, which already uses hydraulic power to move and direct the water spraying components. If the amount of water needed could be reduced significantly by pressurising it with the HPW Dust it could make a huge difference to global water consumption.
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.
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.
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.
Subsea hydraulic components have long been used for marine and deep sea applications. Even in the 1970’s large machines had started to use the first hydraulic components to help with underwater activities for industries such as oil and gas.
Tasks such as trenching, digging, drilling and other heavy machinery activities could be carried out at depths of up to 200 meters below the surface of the water. Hydraulic valves, machines and cylinders were used to drive manipulator arms, drilling tools and track drives.
In these early days it was relatively rare to see these types of machines in operation, so the components were usually costly. However, this evolved over the following years and deep sea hydraulics became an area that was marginally less costly to operate in.
In this century, focus is on deep sea hydraulics and its ability to assist with the sourcing and extraction of fossil fuels and minerals. Greater depths can be reached through the use of ROVs – remote operated vehicles / subsea crawlers. Depths of up to 6000m can now be reached and materials can be harvested using this new generation of subsea machinery.
It’s no longer necessary to position the harvesting and processing equipment on either a ship or a platform. It has to go down onto the seabed to carry out the necessary activities. Hydraulic machinery is ideal for operations such as this due to their power, precision and flexibility.
The type of applications that you’ll see subsea hydraulics used for include the handling of heavy loads and installation of heavy machinery. Tools used to build marine based structures on the seabed such as hydraulic hammers that drive piles are just one of the applications that are used. Others include civil engineering structures such as harbours, marinas and bridges that need to have foundations or objects anchored into the seabed.
ROVs also make it possible to carry out seabed test drillings for oil and gas industry operatives. They can also install heavy equipment that can protect pipelines and cables used for transporting oil and gas, from dangers such as shipwrecks, earthquakes and naturally strong sea currents. They can bury the pipelines into the ocean floor to keep them secure and safe from risks. The ROVs are highly sophisticated in their manoeuvrability and handling.
Another way that subsea hydraulics are used in marine related industries is for deep sea mining of the sea floor. A lot of deposits of high grade rare earth minerals including gold, silver and copper have recently been discovered in the Pacific Ocean. Subsea hydraulics make it possible to harvest them. For example heavy duty ROVs can be operated hydraulically in order to establish the construction required to harvest these minerals.
When it comes to subsea machinery, hydraulics can help with the launch and recovery of highly valuable and expensive subsea equipment in addition to the control of machines such as the ROVs.
There are many challenges and engineering obstacles that need to be overcome in order for hydraulic components to work in the deep sea. Not only must the materials be able to resist the high pressure of being underwater, and so very deep underwater, it’s essential that they can handle the pressure and the salt present in the water. One of seawater’s unfavourable powers is its ability to rapidly corrode materials. Therefore, protection against this corrosion is essential. This might be addressed by engineers with special coatings or by using materials that are corrosion resistant.
To prevent a short circuit, all hydraulic valves that are solenoid operated also have to be protected against contact with water. It’s not easy to hoist a machine up if it needs to be fixed. It’s important to provide subsea machinery with a lifespan that is both lengthy and maintenance free.
If you’re looking for reliable and durable subsea hydraulic power units, contact us today.
In a previous post, we looked at the reasons why a quality hydraulic oil should be used in your hydraulic system. We ascertained that an oil without a good enough base oil can result in all manner of issues. One of them being that oils such as motor oil have too many additives as they won’t easily let go of moisture in the oil.
In this post, we’re going to look at the measurements that you need to take note of when looking for a good base hydraulic oil. First off, take a look at the Oxidation Stability Test results which may state something like ASTM D-943. This is a test procedure which provides some insight into the testing process that the hydraulic oil went through. The results are reported in hours of performance in resisting oxidation at elevated temperatures. For example, this might be 5000 hours.
If it is 5000+ hours then you can rest assured that it has a high quality base oil. Most hydraulic oils will be displaying a report of between 1000 and 3000. If you don’t see oxidation stability on the sheet, then you’ll know that the performance wasn’t good enough to mention. Another report to look for is the hydraulic oil’s pour point. For example you may see -27F listed, which is an outstanding result for just one product.
Those hydraulic oils that of a lesser quality won’t flow at 0 degrees. It’s not common that hydraulic systems that have to operate at temperatures as low as these, but it’s a factor that will provide you with an indication of the quality of your product.
Another number to look for is the measure of the VI. If it’s 100 then it’s most likely a good oil. Synthetic oils may have a Viscosity Index of 120, with lesser oils in the 80 – 90 mark.
At the end of the day, the quality of your hydraulic oil is vital to the good performance of your hydraulic system. Hopefully we have shed some light on what you need to consider when looking for a quality hydraulic oil for your system.
Preserving the quality of hydraulic fluid is something that will make a huge difference to the life span, lack of downtime and condition of your Hydraulic Systems and Machines. If it’s condition is allowed to degrade, you’ll be setting yourself up to have to deal with cavitation, machine damage and eventually the machine could even come to a halt. This is not going to look good in front of your boss nor your next employer.
That being the case, let’s explore what you need to know in order to preserve the quality of hydraulic fluid in your system.
After you’ve completed reading this post, you should understand what hydraulic fluid should be like, whether it needs any additives put into the fluid and how to get maximum life from your fluid.
As we have covered, without your hydraulic fluid being in good condition, there is likely to be a negative effect on the running of your hydraulic machine. We always recommend to our customers that they continue to use the fluid that the manufacturer of their machine has suggested. It’s also wise to use filters in order to prevent the fluid from deterioration through contamination. The pump and reservoir unit should also be considered as these play a critical role in the health of your fluid.
These are the properties that you want your hydraulic fluid to have in order for it to operate at it’s best.
Compressibility – it’s not very easy to squeeze liquids into a lesser volume. This is why precise motion control is one of the strong points of hydraulics. If air enters the system, then it takes it into being compressible and it won’t work as it should. You can test how compressible fluid is by forcing fluid into a rigid vessel with a screwed plunger and measuring the pressure.
Viscosity – this is a measurement of how easily the fluid will flow. Low viscosity fluid (for example water) will flow very easily, whereas high viscosity fluids will flow slowly and with some difficulty. This is what will result in loss of pressure. However, it’s only fluids with high viscosity that will lubricate well, so a balance needs to be sought.
Viscosity index – as a fluid gets hotter, its viscosity will usually decrease. This means that as it heats up it can become less effective at lubricating. Less change can be expected from a fluid with a low viscosity index. It might be possible to improve on this with the addition of chemical additives.
Air absorption – when liquids are under pressure they will absorb gas and then when the pressure is released, they will release it again. This can be seen with fizzy drinks. Air will not be absorbed easily by a good hydraulic fluid without causing foam and froth. It’s possible to add chemicals in order to improve this. Chemicals can be added to prevent foam from building up on the surface of the reservoir.
Oxidation – this can occur when oxygen is in the fluid and combining with elements. It can cause the oil to thicken to produce a varnish. This will stain the surface of the components and will reduce the life of the oil. Although there are additives that can help with this, it’s important to keep out air as much as possible. The main reason for air and fluid mixing is when there is foam and cascading in the reservoir.
Corrosion – corrosion of metals can be caused by hydraulic fluids. This can be helped by using materials that are compatible with it in addition to the addition of chemicals to the fluid.
Wear – when chemicals have been added which encourage the development of surface film where surfaces meet, such as in pumps and motors, it’s possible to slow down wear.
Pour point – this is the name given to the lowest temperature point at which the fluid will flow from a container when tipped up. If you’re working in cold climates, it’s possible to add chemicals to lower this temperature.
Flash point – the name given to the point when the vapour produced by a fluid will ignite when a naked flame makes contact with it. A Pensky Martins apparatus is used to measure this.
If you haven’t done so already, take time to become familiar with these technical engineering terms. They will prove useful for testing, explaining if you need advice from a third party and for keeping records of the condition of both the fluid and your hydraulic system.
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