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Hydraulic systems are renowned for leaking oil. The trouble is, that oil costs money and needing to continually top up becomes a major expense for many hydraulic equipment owners. Here are some interesting but slightly alarming stats from the NOAA (National Oceanic and Atmospheric Administration). Although they are located in the USA, these stats will give you some idea of how much oil is being consumed and also used as replacement.
According to the NOAA more than 2.65 billion litres are entering the environment on an annual basis. Approximately half of this derives from illegal disposal, and 370 million litres of it comes from leaking hydraulic hoses. It’s estimated that it takes just one litre of oil to pollute up to 1 million litres of water so these are stats that should be taken seriously.
If governments were to get serious about pollution and begin to charge for any discrepancy between oil delivered and oil disposed of (measurements would need to be taken by a governing body or by oil delivery companies), then companies could be in for a financial shock. It would certainly become more pressing to repair oil leaks.
What puts a lot of companies off from fixing leaks is that there is always downtime involved. This avoidance will allow leaks to increase to the point where the price of the replacement oil is almost equal to the cost of downtime and repairs.
Re-engineer. Without connectors, a hydraulic system cannot leak. However, a system has to have some connectors, but through the clever use of integrated hydraulic circuits using valves and manifolds, they can be greatly reduced.
Although it would usually be the machine designer who would apply this type of technology, if you have a hydraulic system that has many connections with line mounted valves then it makes sense to replace these to reduce the amount of potentially leaking components and joints.
Use decent connectors. The most unreliable connectors are those with a thread. For example NPT and BSPT both have threads and that can mean a leak path. When tightened, the threads become deformed and then any tightening or loosening can cause further damage and more leaking.
Opt for the elastomeric seal that can be found on the ORFS, SAE, BSPP and UN-O-ring connectors for a significantly superior seal. In summary, you’ll gain far better results if you replace connectors that are pipe-threaded with those that use an elastomeric seal.
The most commonly found hydraulic connection is the JIC 37 flare. This uses a metal to metal seal that does not always remain leak free. In this case you might want to install a conical washer between the flare and the joint’s nose.
Tighten Them Properly — incorrect torque can be blamed for most leaks from 37° flare joints in addition to compression-type tube fittings. The seat contact is inadequate. A torque that is too high can cause damage to the tube and ‘crush’ the ferrule.
Eliminate Vibration — if there is something that can cause stress fatigue, it’s vibration. If there is vibration, it’s key to check what the cause of this is. It could be necessary to install rubber mounting blocks to enable vibration to stop travelling between valves, the hydraulic power unit and the reservoir. Also ensure that clamps support tubes and pipes.
Keep The Machine Cool - keeping fluid within recommended operating temperatures is elemental to enabling components to have a full service life. Going over 85° C (185° F) can reduce service life rapidly. Even going over temperature on a single occasion can damage rubbers and seals and deliver a number of leaks. This is another reason why a hot running system is unreliable.
By using these approaches to reduce the number of leaks on your hydraulic system you can reduce costs and lower the risk of extended maintenance downtime.
Considered chronic users of oil, hydraulic systems can be very expensive to run. However, with some tweaking and careful management, it’s possible to set hydraulic equipment to run very efficiently and reliably without any leaking expense.
Leaking hydraulic hoses can cause serious environmental issues
More than 700 million gallons of petroleum products are allowed to enter the environment every year (National Oceanic and Atmospheric Administration (NOAA)). Although around 50% of this comes from unlawful and irresponsible disposal, up to 98m gallons of it may be coming from leaking hydraulic hoses according to Gates hose manufacturers. With just one litre of oil being capable of polluting up to 1 million litres of water, that’s a very uncomfortable statistic.
Considering the above, you might want to ask yourself how much oil is consumed by each of your hydraulic systems each year. The only way to know the answer to this is to measure the amount of oil you are giving it each year. Every single drop. However, it’s quite hard to control everything so it’s quite likely that measurements such as these don’t happen.
However, in our experience, when we have worked with clients and suggested that they measure their oil, they have been unpleasantly surprised at how much oil is going to waste each year from their large hydraulic machines.
Addressing this issue
Nobody likes downtime. In fact, it’s most often the reason why looking for possible leaks is left as long as possible. It’s not until the cost of replacement oil makes it truly justifiable to take the machine offline for repair, that a business might undertake investigations.
We once had a client who recognised that he was losing so much oil that it was far cheaper to take the machine down even when it would cost £20,000 to repair than it would be to lose the £1000 per week in oil that it was costing. It took just 5 months to make this money back by not paying out for lost oil.
To be honest, we have oversimplified the true cost. Of course, not only is there the expense of the oil to consider, but there is also the cleaning up, the disposal of the oil plus the safety risks involved. Of course, if oil makes it way out of the building, there are also contamination costs to consider. Every one of us is reminded of the cost of removing contaminants each time we buy a filter, however, it costs far more not to remove them.
How To Get Rid of Leaks
Of course, none of us fancy putting our business into a state of downtime, but sometimes it just has to be done. Here are some ways that you can get rid of leaks:
Engineer Them Out
Reducing connections can reduce leaks. Use stack valves, cartridge valves and manifolds wisely and you’re on the right track. Connectors that have tapered-threads such as NPT and BSPT can enable oil to leak as the thread is a path for leaking. When tightened the thread becomes deformed and with any further tightening or loosening the potential for leaks increases.
Connections that are metal to metal can’t be relied on to deliver a permanently leak free joint either. Flaretite manufacture a type of flare seal that uses Loctite sealant to ensure that the joint it makes is leak-free.
Cut down on vibration
Vibration can create leakage by stressing hydraulic conductors, creating fatigue that affects connector torque. To address this it might be necessary to mount rubber blocks between reservoir, hydraulic power unit and valves. Check whether conductors such as tubes and pipes have adequate support with enough clamps.
Keep the Machine Cool
Fluid that gets too hot can impact the reliability of seals as their service life will reduce and fluid that is over-temperature can damage every seal in a hydraulic system and create many leaks. Machines that run too hot are unreliable.
By making these simple tweaks you can save your business and the environment from unnecessary cost caused by leaking hydraulic oil.
Hydraulics has been around for a very long time. But are you aware of how far it has actually come? You wouldn’t be alone if you responded with no. It is a very technical subject that can be quite difficult to understand, but in this article we want to tell you the story of hydraulics! We want to share with you who discovered hydraulics, what it was originally used for and how hydraulic power got to where it is today.
So why don’t we start at the beginning! Where does the word hydraulic come from?
The word hydraulic originates from the Greek word ‘Hydros’ which means water. Why water? Well, this is because water was the first liquid to be used in the hydraulic system. Today, hydraulics includes the physical behaviour of all liquids, not just water.
In this article we want to explain the ins and outs of hydraulic powerpacks. A vital piece of equipment that is used with so many machines we see every day.
In a nutshell, hydraulic powerpacks are self contained units that are used instead of a built in power supply for hydraulic machinery. Hydraulic power uses fluid to transmit power from one location to another in order to run a machine. It really is as simple as that.
So what do they look like?
In order to recognise and better understand hydraulic powerpacks, it is a good idea to get to know the key components. Hydraulic powerpacks come in many different shapes and sizes, some are very large and stationary whereas others are much smaller and more compact. In fact, some hydraulic powerpacks are so compact that they can easily be transported in a small van or even an estate car.
The only real way to identify hydraulic powerpacks is through its main components. No matter the size of the unit, all power packs will have the following; a hydraulic reservoir, regulators, a pump, motor, pressure supply lines and relief lines.
What do these components do?
It may be obvious to some but in this post we wanted to explain every hydraulic power pack component as simply as possible. So here goes.
First up is the hydraulic reservoir which quite simply holds the fluid. Reservoirs will come in different sizes.
Then we have the regulators. Regulators are vital as they control and maintain the amount of pressure that the hydraulic powerpack delivers.
Thirdly we have the pressure supply lines and relief lines. The supply line simply supplies fluid under pressure to the pump and the relief lines relieve pressure between the pump and the valves. The relief lines also control the direction of flow through the system.
Finally we have the pump and a motor. We will begin with the simpler component of the two, the motor. The motor is simply there to power the pump. Easy as that. Now the pump generally performs two actions. Firstly, it operates as a vacuum at the pump inlet and through atmospheric pressure forces fluid from the reservoir into the inlet line and then to the pump. It then delivers the fluid to the pump outlet and pumps it into the hydraulic system. We did warn you that the second part would be slightly more confusing.
So what is the function of hydraulic powerpacks?
Hydraulic powerpacks deliver power through a control valve which in turn runs the machine it is connected to. Hydraulic powerpacks come with a variety of valve connections. This means that you can power a variety of machines by using the appropriate valves.
Hydraulic powerpacks are relied upon by a range of different machines that use hydraulic power to do its work. If a machine is required to carry out heavy or systematic lifting then its likely it would need help from a hydraulic powerpack.
To make it easier for you to understand, we have included a list of trades that regularly rely on our powerpacks. On a building site you will see machines like bulldozers and excavators, which both need hydraulic powerpacks. But, it is not just on building sites that you will find these types of machines. Fishermen and mechanics both need hydraulic powerpacks too. If we did not have them then how would fishermen lift their nets or how would mechanics lift our cars?
When picking a hydraulic powerpack there are a variety of pumps and options to pick from and it is important to pick the right pack to meet your machines needs. It is also important to consider a pack that will help maximise productivity and minimise cost.
Many people will overlook the necessity of hydraulic powerpacks, but they really are vital to ensuring our society runs efficiently.
Do you need to maintain hydraulic powerpacks?
Yes you do and this is hugely important! Hydraulic powerpacks require regular maintenance to ensure they are working properly and safely and to help extend their life. Maintaining hydraulic powerpacks is relatively simple and includes checking the tubing, this can be for any noticeable problems such as dents or cracks. It is also vital to regularly change the hydraulic fluid and look at the reservoir to check for any corrosion or rust in hydraulic power packs.
What hydraulic powerpacks do we provide?
Generally we provide four different types of hydraulic powerpacks. You can pick from a standard powerpack, a mini powerpack, a micro powerpack or a bespoke powerpack.
The standard hydraulic powerpack uses a standard range of modular components and is ideal for the most demanding industrial applications. The mini powerpack is ideal for applications requiring up to 5.5kW. The micro hydraulic powerpacks were originally produced for mobility applications, so are great for when space is limited. Finally, if none of these seem to fit your needs then we offer bespoke hydraulic powerpacks ensuring your application gets the hydraulic powerpack it requires.
Finally, who is the genius behind hydraulic powerpacks?
The man behind hydraulics was Laissez Pascal. A French mathematician, physicist and religious philosopher who lived in the mid seventeenth century. Pascal made observations about fluid and pressure which led to Pascal’s law. Pascal's law states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. Hydraulic powerpacks have been designed based on Pascal's law of physics, drawing their power from ratios of area and pressure.
So, interested in our Power Packs? Come on over to the main website and see what we can do for your Hydraulic Power Pack Needs .
Injuries are a relatively common occurrence for people working with hydraulics, especially those working in the maintenance and/or repair of hydraulic equipment. The most serious injury is a pressurised fluid injection, but accidents can also happen with moving parts when the stored energy in the system is not released before inspections and repairs are made. Unfortunately, it is not routine for tags and gauges to be used to denote places where energy is stored. The engineer must study the schematic thoroughly before starting any investigative work, in order to be sure that there is no danger of anything moving while they are working on the machinery.
If pressure gauges were used to show the residual pressure left in moving parts the engineer could utilise the pressure relief valve to release the stored energy and make the hydraulic equipment safe to work on. Relieving pressure stops anything moving of its own accord, which could be dangerous, and also reduces the risk of high pressure hydraulic fluid injection injuries, which can be fatal.
When inspecting for leaks in seals and hoses, it is important that pressure is released before checking but even then, it is not advisable to check with your hands. Instead, perform a visual inspection and look for other signs of leaks, such as fluid on the floor or on parts of machinery that sit underneath the suspected location of the leak.
Hydraulic equipment can be just as dangerous as electrical circuits for those investigating and repairing faults; but electrical work is governed by strict regulations which include the use of lockout tags and labels denoting the location of potentially dangerous components. Hydraulic equipment is not covered by such stringent regulations and as such, it is at the discretion of the designer whether pressure gauges and safety accessories are included in the machinery at the time of building. These items can be retrofitted by the owner, but this is not often done and this means hydraulic engineers must spend a lot of time reading manuals and schematics to understand where the dangers lurk, before being able to safely get on with any repair work.
Just because it isn't legally required, there are no good arguments for overlooking these safety precautions, but several reasons why they should be addressed., such as: reduced downtime on repair and maintenance tasks, a reduction in the potential for workplace injuries and a speedier repair. All effected by removing the need to spend time studying diagrams to pinpoint potential dangers. Employee health and safety is of paramount importance to employers, and this could well be the biggest reason why hydraulic equipment should be fitted with pressure gauges, relief valves and lockout tags, to prevent tampering with settings and to alert engineers to the locations to address first.
Hydraulic pumps, one of the more common mechanical applications of hydraulic technology, use fluid to push an arm a set distance forwards and backwards (or up and down). One example is the mechanical arms of a digger or other ground-working machinery. A hydraulic pump is perfect for this use, as the machinery works using the set distances between the components of the arms.
A hydraulic gear motor uses fluid to power movement for a much longer distance (or to put it another way, for an unspecified length of time). The motor works by running fluid through a chamber containing two cogs. One is linked to the drive shaft and transfers the power to the component that needs to move, and the other is idle, existing only to complete the mechanism. The same fluid is pumped through the motor chamber for as long as the power is needed, and it works in a similar fashion to an electric motor, but is much smaller and can be used in places where electricity is not safe or viable to use. It is a natural development of the waterwheel that was commonplace in the UK during the Industrial Revolution, powering cotton mills, woodworking and even bellows for blacksmiths forges.
A hydraulic gear motor is more appropriate than a pump for any piece of machinery that needs continuous power in a simple mechanism; a series of hydraulic pumps, arms and cogs can be used to create continuous power, but the resulting apparatus is bulky and made up of several components, which increases the likelihood of mechanical failure. A hydraulic motor, by comparison, can be very small and portable, meaning it is ideal for any application that is a long distance from traditional power sources and remote areas of the planet where other forms of energy are not viable. They are also reasonably simple in construction, so parts and maintenance are not an issue.
Hydraulic motors are ideal for use underwater and in dangerous places like mines and gas works, where the spark from an electric or petrol motor poses a serious fire risk. They are also good for any task where the motor is operated remotely, as the fluid can be pumped a long distance to the motor using comparatively little power and the only connection needed is piping, compared to more expensive electrical cable for running a remote electric motor. What is the most ingenious application of a hydraulic motor you have ever seen? Let us know in the comments below.
Many hydraulic systems leak. In fact, some businesses can and do waste vast amounts of money by not being serious about tracking down and rectifying fluid leakages on their machines. As with any task, it’s critical that you start at the beginning.
We recommend to our clients that they keep a record of how much oil is going into any system, and how much oil comes out when it’s time to do a swap out. If you put in a certain number of litres, but you’re getting less out, you know that it must have gone somewhere – whether it’s an internal or external leak. However, these measurements will need to be scheduled into your top-off process or they are quite unlikely to happen. Those that do perform this task are most often very surprised about the amount of fluid that is going missing from their hydraulic system and the associated financial cost of it.
One of the most common places to find a leak is around the rams, motors and pump. It’s down to the high pressure and the constant movement in this area. With pressure being anywhere in the range of 1000 PSI and 5000 PSI, it’s not surprising that some fluid gets pushed out of the system.
If looking for symptoms, the first thing that operators will notice is a lack of power or force. Alternatively, they notice a drip or a leak. If this is coming from seals, it’s a highly skilled job to replace hydraulic seals. Not only is it necessary to have familiarity with the system in question, but specialist tools are required to perform the job. Components are sensitive to damage due to close tolerances or if the wrong tool is applied or through improper handling.
Unfortunately, there is an associated downtime with fixing leaks. If leaks are left to get out of hand, then it can even get to the point where it’s going to be cheaper to take the machine out of service and get a specialist in to fix the leaks rather than to continue to keep topping up the fluid level.
We know of a business that had a terrible leakage issue. They looked into how much it would cost to repair including the hire of the specialist and parts and found that £20,000 was a lot to stomach. However, when they looked into how much their oil was costing to replace on a weekly basis, it was around £1000. This meant that over a period of time, they would reach the point where it would be far cheaper to fix the leaks rather than to continue to pay out for the replacement fluid week after week.
What we’ve put here though is actually a simplified interpretation of the costs involved. Not only is there the cost of the oil, but there is also the associated cost of safety risks, proper clean up and disposal of the fluid. There is also the issue that where oil can exit, it’s also possible for contamination to enter. There is then the cost of the filters to remove those contaminants.
If you want to eliminate risks, here is a checklist of the approaches to take:
· Design them out. Remove connectors as that is where the leak is coming from. Do what you can to install integrated hydraulic circuits.
· Replace connectors. Select the more superior connection types that do not have threads, and therefore do not have leak paths.
· Tighten them. Quite often the torque is incorrect and this means improper contact.
· Eliminate vibration. Vibration can affect connector torque.
· Run the machine cool. Hydraulic fluid needs to be maintained at reasonable levels of temperature to avoid seal damage.
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