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If you’re new to the power of hydraulic cylinders, then read on. We’re going to look at how they are used. The magic of the hydraulic cylinder is its ability to produce unidirectional force from unidirectional stroke. This gives them the potential to be used in a number of industries, although construction is the premier one. Let’s explore how else the hydraulic cylinder is used as a valuable tool in industry:
When it comes the agriculture industry, harvesters, loaders and tractors with their attachments are all ideal applications for the hydraulic cylinder. It’s also possible to benefit from their use on wood splitters.
Civil engineering benefits greatly from the use of this component. The hydraulic cylinder makes it possible for the operation of bulldozers, excavators, trenchers and their attaching tools.
The power of hydraulic cylinders can be seen in the energy industry also. For example, the gate controls of hydroelectric stations can operate gates to allow water to flow or stop.
Those in mechanical engineering will often rely on hydraulic cylinders to operate feeding devices, automated production lines, transportation devices and plastic forming machines in addition to the production of ecological equipment.
Another area that benefits from the use of hydraulic cylinder is shipbuilding. They can be used in steering mechanisms, transportation equipment and also hoists in addition to several other applications.
Other industries that regularly use hydraulic power are as follows:
· Food, production and manufacturing
Not just one type of the device is in operation as then it would not offer enough solution. Therefore, you can find a variety of types that handle the different roles required. For example, single-acting, double-acting, telescopic cylinders and plunger.
Although the cylinder can differ in looks, style and size, there are two components that you will always find: The barrel and the piston.
If you’re looking for a hydraulic power pack for your system then contact us and we could be able to help.
If you’re curious about how hydraulic cylinders work, then you could find this post to be interesting. Let’s take a look at these powerful components that make it possible to move and lift the heaviest of items with ease.
You may not have ever considered this before, but what do you think deploys those huge wheels that aircraft need to land? They are put away tidily throughout a flight, and then when they’re approaching Heathrow, out they pop and all at the pilot’s press of a button.
Landing gear is operated through a hydraulic system. As with any hydraulic system, there are pipes, cylinders and of course hydraulic fluid. The fundamentals of this are the same as with any hydraulic system. When force is applied at one point, it is transmitted to another through the use of incompressible fluid.
Hydraulic cylinders mostly come in parallel pairs that are of differing diameters and are connected by a pipe. The cylinders will be at right angle to the pipe. This arrangement is then filled with a hydraulic fluid such as oil until the cylinders are partly filled.
The space that is left in the hydraulic cylinders will enable the pistons to operate. In one cylinder, the piston will be smaller than in the other. Fluid will be pushed into the chamber of the small piston and when force is applied, it will push the fluid into the chamber of the big piston as it will be incompressible fluid. This will then move the big piston. Due to the difference in size, the effect of the small piston’s movement will be multiplied. So for example if a small piston has a downward force applied to it of 100 lbs – the force on the big piston will be 900 lbs.
Hydraulic cylinders remove the need for a rigid structure when it comes to transferring force between two different points. This can be used to the hydraulic system’s designer’s benefit and a number of twists and turns can be added to the system. For example, there might be a space constraint. Using the different cylinders at different sizes, it’s possible to create a system that will pull, push or even lift heavy weights.
Although the hydraulic systems that are used in our everyday life are not built with cylinders quite as basic as what’s described above, they are fairly similar. Let’s look at the different components involved:
· Cylinder barrel
· Piston rod
· Cylinder bottom (Cap)
· Cylinder head
· Cylinder bottom connection
· Rod glands
There are two different main types of hydraulic cylinders used. The tie rod type of cylinders and the welded body type. The former are used when there is a need for heavy-duty industrial or commercial use. Some are small bore and others large bore. The welded body cylinder type has no steel rods in it. The top of the barrel of the cylinder is welded directly onto the object that is expected and designed to move. Although these cylinders are small in size, they are used in a surprisingly large number of different machines. In some cases it’s necessary to use a telescoping hydraulic cylinder where the piston rod will retract into the barrel of the cylinder.
Hydraulic power has really evolved over the last 50 years or so. Much of the progress has come from the aeronautical industry, surprisingly. Although hydraulics have been used since before the time of the first recorded history, it’s only now that they have really come of age and have made such a tremendous difference to us in so many fields.
Our current blog looks at Hydraulic Cylinders and acts as a guide to help you choose the correct type of cylinder for your hydraulic system.
As system layouts and sizes vary greatly, it can be a bit of a trial and error process to get the correct measurements for fitment. Luckily some manufacturers, such as ourselves, offer a bespoke cylinder option which can be tailored to specific power units with additional options also available, if required.
We will start with the most common type of cylinder, sometimes known as a catalogue cylinder, as they typically come in a range of pre-set measurements so you can browse through the standard sizes to find the best fit for your system. These are especially popular for smaller systems where the operational length of the system isn’t a big concern.
Standard cylinders can be a cheap, cost effective solution, but you have to bear in mind that if you have cut corners to get a non-bespoke cylinder, you may lose some of the extra efficiency and reliability a custom built cylinder could offer.
Next up are the bespoke cylinders themselves; the advantage of these is that they can be factored into the design of a system so form and function are perfectly suited to your custom build.
There are a number of key areas to look at when designing your bespoke cylinder. These include:
Servicing and maintenance plays a big part in ensuring that your cylinder is in prime working condition and with standard cylinders where ports and other components come pre-positioned, being able to service the cylinder easily could become a problem, whereas with bespoke versions the layout of componentry has been optimised to work closely with the system, thus maintenance is more straight forward.
At Hydraproducts we sell both standard and bespoke cylinders and these now form part of our new Components Division, which you can find out more about by clicking here to visit our new Hydraulics components webpage where Cylinders, Valves, Accumulators and more can be found.
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.
As we have looked at before, a failure in hydraulic cylinders is quite often related to a seal failure. Although the price of a seal is not particularly high, domino effects can make this a very expensive occurrence. The financial costs of loss of production, engineer downtime and / or calling in engineers can soon add up. It’s for these reasons that it’s important to look at what is causing the failure of the seal first.
The key issues behind seal failure are:
Bad installation of seal. When the seal is installed, the following facts need to be considered as this is something that can easily go awry:
· Is the equipment and the room clean enough to insert the seal?
· Protect the seal from cuts or any damage that may prevent it from working at its optimum performance.
· Lubrication needs to be correct
· The seal gland should not be overtightened.
· The seal must be placed the right side up.
Another primary cause of failure of hydraulic seals. Dirt, mud, dust or grit or even internal contamination through metal chips circulating can have a devastating impact on hydraulic seals. Once hydraulic fluid starts to breakdown it can turn to sludge. Another entry point for contamination is the rod retraction cycle. This is why it’s important to install a rod wiper and why the fluid system needs to be well filtered.
Incorrect material. Seals manufactured with unsuitable materials can lead to chemical breakdown. This can occur due to the changing of hydraulic fluid also. Watch for discolouration of your seal to identify when it’s undergoing chemical attack.
Degradation from heat. Once you see the seal change colour and go hard or brittle then there could be heat degradation going on. This can lead to loss of seal. It could be that you need to change the material of the seal, or even increase lubrication.
Summary. Sometimes seals fail because they aren’t the right size or the conditions for them are not optimal. If you cannot change the conditions, at least ensure that you have the right size seal, made from quality material and you should see some improved results.
If you’re fairly new to the area of hydraulics or you have an intern working with you then you may find the following information useful to read or share with others.
Before we get started – hydraulic principles are not easy or straightforward until you’ve delved in and learnt a few things. Fluid dynamics, hydraulic mathematics, circuitry and related matters can be downright complicated and that’s why it’s necessary to share information of the type that you find in these blog posts. Goodness knows what any of us did prior to the development of the internet. We would have had to go out of our way to build relationships with others in the industry in order to have free access to their knowledge. But we do have access and thank heavens for that.
With much gusto, let’s look at the basic fundamentals of hydraulics.
It was knowledge founders such as Newton, Pascal and Galileo who first discovered phenomena that was considered interesting, and actually formed the basis of some of what we know today. Way back in 1650 Pascal came across and then formalised the ‘Law of Hydraulics’. It took another 150 years to actually start using and applying that knowledge for practical purposes.
Hydraulic devices operate based on his law which states that confined liquid will carry the power of any external force that is exerted upon it. So much so that it will be carried to every part of the interior of the vessel that liquid is in.
When a hydraulic pump is in use by a mechanic and he is exerting force to confined liquid, then that power will be transmitted through the liquid, whether it’s in a pipe or a hose right up to the piston which will then be forced to move.
Although what you read above is a simplified version, today’s hydraulic machines use the exact same principles, but the mechanics may be replaced by an electric motor or even a gasoline engine. There could be more hoses, some relief and check valves to go through on the way. There could even be a few return lines and a reservoir of fluid to cross. Whatever the case, the action and the result remains the same; movement.
When it comes to how much force is either input or output from devices of hydraulic nature, a pressure measurement is used. This is recorded in the format of pounds per square inch, or psi.
To put this into perspective, 1 psi is equal to one pound of weight put onto an area of 1 square inch.
If 10 pounds of force were put onto 10 square inches, then the result would be the same – 1 psi. If there is a liquid pressure creating a force against a piston then it will be measured either in tons or pounds. A pressure of 100 psi on a piston that has an area of 10 sq inches will be 100 psi x 10 (square inches) or 1000 pounds.
Although there will not be a lot of fluid displacement when a small piston is pushed down in the pump cylinder. Therefore, it will only be enough to move the larger piston a little or short distance. Although a large advantaged is gained in terms of force, there is not much advantage in ‘distance’.
This can be illustrated as follows. Imagine a man pushing his hand against a wall. He can push as much as he likes, but the wall is going to be opposing him with resistance. Without that resistance he would not be able to push, as his hand would just move through the air. This is something that applies to hydraulics too. Without the same resistance, there won’t be the expected result. For example, although a pump might be rated to deliver an output of 10,000 psi if it doesn’t meet with an equal resistance from a cylinder, it won’t output that 10,000 lbs of pressure.
When it comes to hydraulic pumps, there is a variety of different designs including:
· Piston pumps
· Vane pumps
· Gear pumps
When it comes to cylinders, you can expect to come across:
· Gravity return
Valves are also is use, and this is what performs the large variety of functions that hydraulic machines are capable of.
For example, the lowering and raising of a barber’s chair, brakes in cars, the hydraulic raising and lowering of the landing gear in planes and even the jack that is used by many lay persons and mechanics to change the tyre on their car.
Years ago, low pressure is what was popular and in use in hydraulic systems, but these days there are far more high pressure hydraulics being utilised. Strangely enough the safety factors involved are similar, with higher pressure ranking as being slightly safer than lower pressure. The largest benefit of using high pressure equipment is that it is usually smaller compared to a lower pressure device, but will deliver the same amount of force.
This has been a rather eclectic collection of facts about hydraulic systems, but together they should give a deeper insight into how this very clever power delivery system works.
Keep following our blog for more insights into hydraulic systems.
The global rise in construction and infrastructure investment, as well as the trend towards increased mechanisation of agricultural processes will benefit the manufacturers and suppliers of hydraulic cylinders over the next decade. These worldwide trends are helping to drive the industry towards a value of $16.44 billion by 2025, according to research conducted by Global Market Insights Inc.
Double acting hydraulic cylinders have dominated the market in recent years, with a global revenue of $7 billion in 2015, mostly due to an increase in demand for mobile equipment. Mobile hydraulic equipment is expected to see a growth of around 4% in the next few years. Welded hydraulic cylinders also featured heavily in the product landscape and this sector is predicted to be worth $11 million by 2025, driven by a rise in heavy plant equipment and the need for customisation for specific applications; a factor that will play a large part in this growth.
Weak economic indicators suggest there may be a slow growth over the next five years in some sectors, as global financial markets adapt to the changing political landscape, but there will be a significant increase in the demand for hydraulic cylinders over the decade as a whole. Governments in developing countries have pledged to invest in infrastructure projects; the Indian government has indicated an investment of $325 million in the infrastructure development by 2020, and in Russia, the move towards mechanising agricultural processes will create significant growth in the demand for hydraulic cylinders for farming and food processing equipment. The sector enjoyed a growth of 3.6% in 2015 alone across Russia and the trend is forecast to continue in that vein.
The increase in demand for materials handling equipment such as; cranes, forklifts and production line machinery will be especially large in the Middle East, with a predicted 5% growth in the market by 2025 driven by that demand. In the USA, the spending in aerospace and defence sectors will drive the growth of the hydraulic cylinder market to an estimated $3 billion by the same date, with increases in manufacturing and construction projects backing up this rise in the demand for hydraulic equipment.
In China a move towards improving infrastructure will see a growth in the hydraulic cylinder market, raising the market share from $0.79 billion in 2015 greatly as the country develops both urban and nationwide transport networks. Maintaining the manufacturing industry in China will also reinforce the demand for hydraulic equipment, as this sector has been the main driving force behind the rapid economic growth the country has enjoyed over the past few years. Investment in infrastructure has been made possible by this significant economic activity.
Germany is also set to play a large part in the rising demand for hydraulic cylinders as it concentrates on renewable energy sources, with a growth of 4% predicted in this sector. It is also expected that more specialist and customised cylinders will be needed for the renewable energy market, leading to better developments in hydraulic cylinder technology that will then help to continue the growth of the sector from 2025 onwards.
As construction and infrastructure spending increases globally every country will be investing more and more in hydraulic cylinders; with specialists set to benefit from the predicted move towards clean energy sources, particularly in Europe, as well as the retro-fitting and replacement of outdated technologies in the agricultural, infrastructure and manufacturing sectors of the Chinese, Indian and Russian economies. Materials handling especially will see a steady growth over the forthcoming decade in most countries, but especially those planning to spend more on construction and production, such as America and the Middle East.
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