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In this day and age the word ‘Energy Saving’ seems to be the number one buzzword with manufacturers working to maximise their productivity whilst saving as much energy as they can. Fortunately, in the hydraulics industry which has seen huge leaps in technology over the years, it is possible to design a power unit to maximise its running efficiency whilst still maintaining reliability.
There are a number of key areas of a hydraulic power pack that can be developed to make them more efficient and these are explained below:
Correct hydraulic pump specification – It is essential when the end user specifies which hydraulic pump they need for their application they should aim lower rather than higher, as lower pressures going through the system will aid efficiency and avoid working the system too hard.
Variable Displacement Pump – This is a device designed to convert mechanical energy into fluid energy This is carried out by varying the displacement of the pump while it is running, which basically means the amount of fluid pumped per input shaft revolution.
Various pump compensator circuits are available that ensure pump flows closely match those required by the hydraulic system, thus reducing energy lost through heat etc.
System piping – In the design stage of a power unit and its installation, it is always best to try to minimise and bends in the system as this will allow the hydraulic fluid to flow more freely and efficiently. Pipe sizing is crucial to minimise pressure losses that add to the power requirements.
Component specifications and positioning – When creating a bespoke power unit it is crucial to successfully plan where componentry is to be situated including pumps, motors, tubing, valves etc. and components such as accumulators and should be designed correctly to ensure they are suitable for the type of unit that is being built and the load that will be added to it whilst in operation.
Lightweight materials – As in many things, using lightweight yet strong materials can help a system lower its footprint and improve system reliability by not putting as much stress on internal system components. Aluminium is an industry favourite for hydraulic power units, as it has all of the above qualities and is a cost effective and long lasting solution.
Inverter Drives – A good device to consider if you want to make your power unit more efficient, as it allows you to adjust the output speed of the unit’s motor; some modern drives can make units 50% more energy efficient while also reducing noise levels and environmental impact.
Recent surveys conducted among hydraulic engineers show that the majority of them believe that inverter drive usage will increase considerably over the next 3 years.
Unit location – One major factor, which, if carefully managed can save energy as well as prolong the life of a system is its positioning. If for example if the unit was placed in a dusty environment where particulate matter could cause a problem with filters etc. it could severely restrict the running of the system and thus reduce its energy efficiency, whereas if the unit was placed in a well-ventilated area it would drastically improve its running, making it more energy efficient and preserving the life of system components
So we can see from the above energy saving measures that if a build project is managed correctly, taking the above points into account, it is likely to be a reliable, efficient and energy saving system that will save you on costs long into the future.
Are you interested in what can cut costs when it comes to Hydraulic Power in your business?
We can only imagine that the answer is ‘yes’ as most of us are. Well, we’ve got some good news for you. Today, we’re going to look at what the most common reasons are that hydraulic components fail, even those that have not been in service for long.
These points are worth making a note of:
1. Oil changes. It’s not necessary to keep changing the oil unless you have one of thes2 following conditions occurring.
The oil has degraded so far that the original additives have changed its makeup. Changing oil just because you feel it’s about time it’s changed is going to cost you a lot of outlay as oil is expensive. The larger your reservoir, the worse off you’ll be. However, if you keep operating your system with degraded oil, then that could cost you even more. Even changing the oil based on how long it’s been in service isn’t going to help. Oil needs to be analysed to fully understand its condition.
If you discover that your oil is contaminated with particles, the more economical manner to deal with this is to remove the particles through filtration.
So in summary, only change the oil when the additives have been depleted and the base oil is useless. You will have to perform oil analysis to make your decision.
2. Filter changes. It’s the same story with hydraulic filters. Changing them based on hours in service could mean that you’re too early or even too late. Early brings about waste as their capacity is not reached and you’ll be throwing away an unused amount of filter time. Changing them late is also an error as the particles will not be removed from the oil and therefore, it could lower the lifespan of each component in the entire hydraulic system.
The most effective approach is to only change filters once they have become full of dirt, but prior to the bypass valve opening. This may require a mechanism to be added that will monitor the pressure and deliver an alert when a point is reached. A clogging indicator is one of the most basic methods of handling this. However, continuous monitoring of pressure drop through the use of a differential pressure gauge or a transducer is the optimal solution. In summary, changing filters on hours is not maintenance effective, or cost effective.
3. Heat. If you’re driving along and you notice that your car engine is overheating, you would most likely stop. Most equipment owners won’t run an engine that is overheating. They know it’s going to cause problems. However, the same cannot be said about operators of hydraulic system.
Just as with a car, running an overheated engine is the quickest way to destroy hydraulic seals, hoses and other components. How hot is too hot? The answer depends on the viscosity of the oil in addition to the hydraulic components. Viscosity lessens with increasing temperature, so the answer is when the temperature is high enough to stop the oil lubricating as it should.
When it comes to hydraulic components, it’s worth noting that a vane pump needs more viscosity than a piston pump would. If you have a vane pump in your hydraulic system, then you’ll want at least 25 centistokes to be maintained.
Temperatures over 82°C will cause damage to seals and hoses in addition to accelerating the oil’s degradation. Never allow your hydraulic system to operate above 82°C with a viscosity lower than 10 centistokes.
4. The wrong oil. The most important element of any hydraulic system is always the oil. It’s what keeps everything lubricated and it is also what transfers the power. With these two major tasks to handle, keeping an eye on viscosity is a must.
The viscosity of the oil is what will determine the temperature at which the system should be run. You may have heard this referred to as temperature operating window or TOW. A temperature that is too high will prevent the oil from flowing or lubricating as it should. Oil that has a viscosity that is too low will not deliver adequate lubrication either. Keeping an eye on this will also ensure that you power isn’t lost due to either internal leakage or mechanical friction.
You don’t want increased power consumption as it will cost you more. The best way to handle this is to check what your machines temperature operating window is and to ensure that your machine operates within that window at all times. We won’t go into how to do this here, as it’s rather complex, but it’s something that does need to be addressed.
5. Filter locations. There are two locations for filters that cause the most problems – the piston pump and motor case line and the pump inlet. You may have a strainer attached to the pump inlet to collect any ‘garbage’ in your oil, but this oil is being drawn from a reservoir, not somewhere where there should be any garbage.
The pump inlet is also positioned off the bottom, so there should not be a lot of dirt passing through. By placing filters here, it can affect whether you get maximum pump life. If there is any form of restricted intake, it can reduce the lifespan of the gear pump by as much as half. Hydraulic pumps are not built with ‘sucking’ in mind! The way to handle this is to remove any suction strainers or depth filters on either the pump inlet or the piston pump.
Applying these points should be helpful to any hydraulic system operators and should deliver methods to save yourself and your business great expense.
Until next time..
Hydraulic filtration is a vital component of keeping a system running smoothly.
For example, did you know that up to 75% of failures with fluid power can be attributed to contamination? With the use of hydraulic filters, contamination damage can be significantly lowered which can not only cut down on expense but lower that 75% drastically.
If you’re looking to save costs from less downtime then it’s also time you looked into what a difference hydraulics filtration can make for extending the life of your equipment. Running your system optimally is essential when it comes to cost saving, but protecting its longevity is also a critical element in running any business efficiently.
Muck and dust can destroy a hydraulic system, that’s why it’s essential to make the best use of hydraulic filters. You wouldn’t even be able to remove that dirt yourself, as it’s likely to be dust that is so fine that you won’t be able to see it without the use of a microscope. Dirt has the same detrimental effect as sandpaper or gravel and not only will generally deteriorate the system, but it could even destroy it.
However, through the use of a hydraulic filter system you will be able to maintain control over the level of contamination and by doing so reduce the failure of systems by as much as 75% just be removing that dirt.
Hydraulic parts are expensive. Combine that with down time and having to keep engineers on hand to fix worn components and that’s a lot of expense to deal with. Putting filters into place can even save costs by increasing how long the hydraulic fluid will last.
Degradation of fluid – hydraulic fluid that contains fine metallic particles can degrade rapidly through chemical breakdown. Without protecting against this, there could be issues such as slippage, internal leakage, corrosion or sticking parts.
Scoring of surfaces – this can occur when particles get trapped between surfaces of seals
There’s no doubt about it, but …
· System performance is affected by dirt levels
· Hydraulic filters can control levels of dirt. Without using this management method, the system will get dirtier and dirtier until it fails.
In fact, hydraulic filters are the only way to control how much dirt is in fluid. Without them you will be forced to change out the hydraulic fluid regularly, which can be a time consuming and costly event.
Hydraulic system dirt particles are incredibly small. In fact, they are so small that they cannot be seen by the human eye – and 98% of hydraulic fluid has some dirt in it.
Engineers have found that when it comes to size of particles in samples taken from operating systems, the smaller the particles, the more dirt there is in the system.
So where do these particles come from that we have to work so hard to deal with?
In order to have an idea of what goes on inside the closed system, let’s examine where these particles come from.
Instead of enjoying the typical 20 gpm that is the measurement of a pumped flow from a 2000 psi system, you can expect to see something in the region of just 10 gpm. Although your pump will still produce for you, you’ll discover that the degradation results in just 50% efficiency and you should als be prepared to experience extra heat and other unwanted issues.
As with any hydraulic system, there is an optimum level of cleanliness, but there is a point where you cannot get any better performance out of the system by improving the quality of the fluid. However, with the use of hydraulic filters you should be well set to extend the life of your machinery.
Is your hydraulic system stuck in a breakdown and repair cycle? In today’s blog post we share with you 3 simple ground rules that will provide you with the opportunity to stop being terrorised and exhausted by this.
As with anything in life – the more you put in, the more you get out. This fact also applies to the results that you can gain from hydraulic equipment. You do the maintenance, and you can expect an increased level of reliability. Keep maintaining your system for best results.
Any machinery should be an asset to your business. You shouldn’t be in a position that you are beset by issues that are both time and profit consuming. Continually replacing oil, seals, pumps, cylinders, filters and valves can be costly, let alone the down time caused by an unreliable machine that can stop work at the most disadvantageous of times.
Even if your troubling fault has gone away in the short term, you know that it will soon be back, helping itself to your finances and sending your employees to spend the afternoon playing cards whilst they wait for the engineer to fix things up. Even if your company can afford to support such times, it certainly isn’t doing it any good.
If your machine is becoming more of a drain than an asset, then it could well be time to look for what the core problem is so that you can fix it, once and for all.
Before you get started, know that you are capable of fixing this issue and if you follow these 3 ground rules then you’ll be working your way to a satisfying ending:
Your first mission is to identify the temperature operating window (TOW) of the machine. The TOW is vital for the machine to run at optimal output with minimal downtime. Even if you tune up the machine with all the latest components, if it’s run outside of the TOW, then you will experience ongoing issues.
We’ve seen that many people don’t spend the time that is necessary to truly understand what the TOW is of their machine. However, it’s something that is essential knowledge for the wellbeing and reliable operation of your machine.
Something that will directly connect to the TOW of your hydraulic machine is the viscosity of the oil. This will determine what the minimum and maximum temperatures are that your machine will operate in safely.
Exxon Mobile Industrial produced data that specified that the initial viscosity is what the TOW depends upon. You should also be checking whether the machine’s actual temperature operating window is within the optimum temperature operating window. If it isn’t, then there is a need to change something.
The next point that you need to consider in your quest to keep your machine running well, is that each machine has an efficiency that will depend upon both its design and the components that are in use. However efficient the machine is at converting input power into work, will be closely tied to the level of heat that is being produced.
If the temperature is not within the safe TOW then it could get heat damaged and this in itself will make it unreliable.
Of course, clean oil is essential for hydraulic machines to be reliable and blessed with a long life. There are many aspects of this including the contamination caused by particulates and water. You’ll need to check whether you have optimal operating pressure, whether the components are suitable and of course, what type of system you’re running.
It’s not always easy to control how much contamination you have. However, it’s key to remember that contamination plus temperature work well to create oil failures. You can experience sludge build up and varnish as a result of not keeping on top of filter changes, prevention of water contamination and failing to test oil samples.
According to our own engineers in addition to our contacts in the hydraulic industry, most of the major failure causes (up to 90% of them) can be avoided by following these three rules. Wouldn’t you rather have a machine that is reliable?
Keeping overheads low is a fundamental of good money management in business. When your supervisor tells you that the company are pulling in its purse strings and he wants you and your department to help, it’s might not always obvious as to how you can cut back on costs, in particular in this day and age of expensive parts and fuel.
One approach is to save on fluid. Although your hydraulic system may not even be leaking, if you could keep your oil in service longer than usual, whilst not putting your machine at risk of damage, then you know you’re going to be his favourite employee this month.
Here’s how to do it:
Keep it inside
The most important thing is not to waste it. Although you may have a couple of slow leaks that are on your list to be fixed at some point, they are costing you more as every day goes by. The price of oil might be lower than it was, but it’s still pricey. Solving leaks comes complete with a cost reduction. If you don’t attend to them, then you’re affecting your department’s economy.
Keep it responsive
Keeping your oil within optimal operating temperatures offers many advantages. For one, it’s going to have a longer life. By allowing it to get just 10 degrees warmer, it will not have an extended life according to Arrhenius's Law. There will be negative reactions including oxidation. This is caused by air entering the system and hydrolysis – the presence of water. The warmer the oil, the more you’ll suffer from these.
In order to illustrate this – consider what happens when you have cooking oil at home. You could pour it into a cup and leave it on the side. It will take a long time to change colour. However, if you put it into a frying pan and heat it as hot as you can, you’re soon going to have a pan of darkened oil.
Some oils have anti-oxidant additives added. In addition you may want to consider installing a heat exchanger, increasing the number of filters and magnetic plugs and even going so far as replacing any copper or brass tubings under circumstances where the pressure rating is more than 10 bar.
If you do opt to use magnetic plugs, then ensure that there is regular cleaning of them. Otherwise the particles may be dislodged by any oil surge and then they will be back circulating around your system and causing damage. In addition, using the magnetic plugs will help to reduce the work of the filter.
Keep the water out
Water can damage oil. It can also compromise any additives in it. Take ZDDP which is an anti-wear additive, add water to it and you’ll find that it’s completely unstable.
Keep it clean
It’s difficult to keep hydraulic oil clean. Every time you access the system there is a chance that it will collect dust particles. It’s also likely that particles are building up from wear inside the machine. Certain metals are worse than others when it comes to increasing how fast hydrolysis and oxidation happen. These metals include iron, copper, lead and zinc in addition to water. It’s also likely that particles will attach themselves to any additives in the oil, which will lead to depletion of the additives.
In summary, gaining extended longevity from your hydraulic oil comes from good maintenance; keeping your machine leak-free, keeping oil at optimal temperature and clean. Don’t change it until the oil has degraded or your additives have extensively depleted.
Performing maintenance often and well will keep you in the good books of your boss. There’s nothing better than good filtration and the prevention of impurities to keep the fluid clean. You may also want to look at your oil storage system prior to oil being entered into the system. For example, keeping oil barrels horizontal can protect them from water collecting near the bungs. It will also mean that the bung is kept wet and therefore will be more effective as an airtight seal.
Let us know how you get on and if you have tips to share on improving hydraulic system economy, do tell.
Providing all the necessary diagnostic tools to a hydraulic system technician almost guarantees that the source of an issue will be discovered and remedied rapidly. However, as with any ill, prevention is better than cure. Using the diagnostic tools on a regular basis can identify any trends that could result in the failure of a component.
Hydraulic system fluid contains many answers
Quite often, it’s the hydraulic fluid that reveals the answers as to where potential problems will arise. For example, taking a fluid sample can provide a multitude of measurements including how much of the following are in the fluid in addition to any signs of oxidation which is typical of being subjected to too much heat:
There are some tools which can make taking samples easier such as a ply and sampling valve. It also means that you won’t further contaminate your machine by adding more contaminants to it.
The value of sampling fluid regularly twinned with the fact that hydraulic equipment is usually caked in some form of dirt or dust, does not make an easy marriage. It’s essential to keep that dirt out of your system and your sample. Engineers know that sampling from hydraulic systems is a risk that engineers have to take. It’s a risk to take the sample as there is a good chance that something from the surrounding environment could enter either the system or the sample. Nobody wants dirt, particles or even water in their hydraulic system.
The risk increases when it’s necessary to draw the fluid from the hydraulic motor. Unfortunately a tube must be inserted through an open port that is accessible once an access plug has been removed. This makes it possible for contaminants to enter the system or even to stick to the tube and then be inserted directly into the fluid.
Of course, being careful will prevent contaminants from entering the hydraulic system, but it’s very important to be very careful, otherwise the fluid could be compromised.
If the environment that you keep your hydraulic system in is far from clean and dry, then you may prefer to use a sampling kit. It cuts down on the potential for contaminating the hydraulic fluid. It is not funny when you go out of your way to ensure that everything will be ok, but then realise that something must have gone wrong when you find a large particle in the system.
The sampling system is inserted into the access plug that the pump came with. Once the plug is in place, then I won’t protrude more than 1 inch, which makes it a very easy system for those who are limited to smaller space.
Then once the tap is in place, it’s easy to just unscrew the cap which will expose a cavity where you can easily take a sample from. There is then a sampling probe which will connect to the sampling valve. You’ll then find a length of clean sampling tube that connects to the vacuum pump and a clean sample bottle. Just pull on the handle to draw out fluid for adding to the sample bottle.
Taking clean samples is essential in order to take a balanced view of what’s going on with any hydraulic system. It’s possible to attain this by using one of the sampling valves that are available on the market. They create a closed loop circuit which will prevent any contamination from entering the oil sample. The sample can only be taken once the probe is fully engaged with the valve. Once the sampling probe is disconnected the sampling valve will reset.
By taking clean samples, you can discover what is going awry with your hydraulic system, and even predict potential future issues. However, if it’s not clean or you introduce further outside dirt or muck, then it’s not going to be at all helpful and you’d be better off not doing it at all. Ensure that you keep your sampling clean to promote the ‘health’ of your hydraulic system.
Although using high-pressure hydraulic systems is considered to be one of the safest methods of applying force, there are still some important factors to take into account. They are powerful tools and can take on any bending, lifting, pushing or pulling work that you need performed, but there are some important safety factors that need to be observed.
Surprisingly, one of the weak points of the hydraulic system when it comes to safety is that it is very easy to use. This can lead to complacency and in some cases abuse. As with any type of equipment use, there are rules to be followed and disciplines to observe in order to get the best from these machines whilst keeping yourself and others in the vicinity of the equipment safe from harm. Following these guidelines can also often ensure longer lifespan and greater efficiency of the machinery.
In the following passages we look at the different areas of safety that will need to be taken into consideration when dealing with high pressure hydraulic tools.
Just as with any equipment, it’s necessary to observe standard safety rules. This means that gloves, safety glasses, boots or safety shoes and a hard hat all need to be worn. As in any environment that can be hazardous, these should be considered fundamental necessities.
Although most engineers will take the most obvious precautions to avoid accidents whilst taking the longevity of the equipment life into consideration, most mishaps and issues will come from either not operating the equipment properly or not assembling it in the right way. It’s important to understand each function in addition to being clear how it works. Take time out to learn your machinery and how it works.
Lifting of loads that are over capacity is something that can result in trouble. Not only will the cylinders be at risk of damage but it can also result in bent plungers and blown seals.
Keep in mind the following points:
- Take an estimate of what you think the load will be, then apply a suitable safety factor.
- Keep in mind that some of your pumps will be equipped with relief valves whilst others won’t be.
- The use of a gauge will help to give an indication of which operating loads are safe.
- Your gauge should also be used to determine whether there is any pressure in the system before you make any changes or breaks in the hydraulic connection.
- Check your environment before you either advance or retract a cylinder.
Fundamentally, two types of cylinders are used in hydraulic systems. The single acting and the double acting.
Single acting cylinders may be any of these types:
· Spring return
· Load return
Double acting cylinders work with the use of hydraulics and advance and retract.
It’s important that you follow these safety guideline rules for cylinders:
- If you need to position the cylinder on the ground, ensure that the base is able to bear the weight of it. It wouldn’t be funny to watch your hydraulic cylinder disappear into soil. A jacking based should be used, or at least a steel or timber plate that will enable the load to be spread.
- The saddle should have the load spread across it, and not be point loaded.
- Stay clear of and be careful around any areas that are directly below a load that the hydraulic cylinder is supporting.
- Situate your cylinders in order to give enough clearance space for extension of them.
- Excessive heat is any heat that is above and beyond 65°C. This needs to be avoided otherwise packing will be softened and hoses weakened. If there is heat that is not avoidable, use either a piece of metal or a heat-resistant blanket to protect the cylinder.
- Keep oil connectors clean and wipe any couplers before they are connected. Dust caps are provided for a reason and that’s to keep dust and dirt out. If you choose not to use them, be aware that you’re likely to experience scoring of the cylinder walls and this can lead to the eventual failure of seals.
- Over-extending cylinders should be avoided as not all of them have safety stop-rings installed.
- If you need to add oil to the pump, check whether the cylinder is already extended, if it is be sure not to disconnect them. The trouble with having too much oil in the system is that your reservoir could become pressurised and blow. If it doesn’t blow it will rupture.
Hydraulic Hand pumps
Depending upon the speed and oil capacity of your system, there is likely to be a pump available for each cylinder. These may be power-assisted or they could be manual in nature. Those applications that are lower speed and where it’s necessary to have that added human ‘touch’ will usually have a hand pump. If the application needs faster movement, or the cylinder is particularly large, then it will use a power pump.
It’s essential that the pump valve is suitable for the cylinder. For example, with single acting cylinders, there is usually a pump that has a 2 way or a 3 way valve. This equates to one outlet. When it comes to double acting cylinders you’re likely to find a 4 way valve which means it has 2 outlets. It’s dangerous to use a 2 way valves in combination with a double acting cylinder.
Check the pump reservoir level before using. Fill using the correct procedures if necessary. Remember that pump hoses will shorten when they are filled with pressure, so ensure there is enough slack to handle this.
With regards to power pumps, you can expect to come across one of these types:
· Petrol / Diesel
It’s fairly obvious that hose failure can occur after heavy objects being dropped on the hose cause damage, but it’s surprising how this escapes the thoughts of many engineers. We often hear stories of how something was dropped but then it was a forgotten memory and the next thing the engineer knows, the hose has failed and there has been a hydraulics disaster.
Another strongly recommended tip is that hydraulic equipment should not be carried by the hose. Most of us are well aware of this, but you will need to keep an eye on any young apprentices who are as yet unfamiliar with the norms of operating hydraulic systems. There should also be an eye kept out for any sharp bends in the hose. The internal wire braids can be damaged from this type of event and this will weaken the set up and could result in leaks and at worst a lethal situation.
An essential fundamental when it comes to hydraulic system safety is to check all fittings, hoses and connections to ensure that they are tightened as they should be and that they comply with the amount of pressure that they will need to be able to handle with your specific system.
We generally recommend that hydraulic systems use oil that is suggested by the manufacturer. The system will usually have been manufactured around that oil and the creators know that it will perform best with that particular one. You will need to change the oil periodically. This will ensure that the system does not get damaged by dirty oil. Ensure that hydraulic oils do not touch your skin.
After you have finished using your hydraulic machinery, it’s time to get it ready for the next job. You will need to clean it before storing it. You can do this by wiping it down. You will also need to lubricate any parts that are exposed.
In conclusion, operating hydraulic systems safely entails using the right cylinder with the right pump and the right oil. Although these rules may seem obvious and safe, it’s surprising how many people fail to adhere to them and put themselves and others in danger. Hydraulic equipment is very powerful but it can also be very dangerous.
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