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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.
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 .
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 hydraulic cylinders are so incredibly simple, equipped with just a steel rod, an iron tube and a few other pieces holding everything together, they are remarkably powerful. They provide the workhorse brawn of our nation’s industrial works and are what makes it possible to rapidly move earth and other materials around us. In this post we look at how the hydraulic cylinder works.
It’s a basic lore that area x pounds per square inch (PSI) = Force. For example, if you put 1 pound of pressure onto a 1 inch object, you will have 1 pound of pressure. If you put 1 pound of pressure on 2 inches, you will have two pounds PSI and so on and so forth.
This means that the size of the piston is closely related to the power of pushing or lifting available.
Inside the cylinder, the fluid will push against the piston. The diameter of the piston is known as the bore. When it comes to powerful lifting, it’s the larger bore cylinders that can perform the best and will be employed by the larger applications that we see in use.
Inside the piston is the hydraulic fluid. It needs to be contained by a seal. If the seal is in anyway defective, it won’t be able to perform to its utmost capacity. Although you may not see any oil or fluid on the outside, the damaged piston seal will make it possible for the oil to bypass the piston. This will not result in ultimate pressure, and so the lifting will not reach the level of effectiveness that it should.
The shaft or rod of the cylinder is what travels through the head of the cylinder. It attaches the piston to the fitting at the end. The strength of the piston in combination with the diameter of it will be what determines whether it will bend. Pistons take a lot of stress and it will need to be strong enough to cope with the ‘side load’ that it will get from being extended.
When it comes to the total distance of travel between a fully retracted length and a fully extended length, this is known as the stroke.
The head or gland of the cylinder is the part through which the piston rod travels. Inside the gland, the piston rod seal has a weakness for leaking as it’s exposed to the elements ad it also collects debris.
The cap or butt of the cylinder is located at the base. In some cases, it does not require a seal as it is welded to the cylinder tube.
Hydraulic cylinders are wonderful inventions, and without them our world would not be what it is. For more on hydraulic systems, follow our blog regularly.
Hydraulic power packs, such as the ones supplied by Hydraproducts, are a vital part of the construction industry. With a huge push on new home building across the country, it is a daily occurrence to see heavy plant equipment moving earth and preparing groundworks for construction. All of these ‘earth moving’ machines use hydraulic power to effect motion in the moving parts, with hydraulic rams serving as the muscles of the machine to raise and lower a digging arm, or to move large pipes into place for infrastructure development.
Hydraulic power packs allow the machinery to generate more power in the moving parts than if just the engine power alone was directly driving the hydraulics, so they mean a smaller excavator can move as much as a larger one without the need for that extra space. On new build sites, there is a lot of space to start with, so there is no issue with the largest machinery manoeuvring around the site. When houses start to go up and roads are installed, there is less machinery space and it makes sense to use a smaller version of a particular machine that has the same power capabilities.
A hydraulic power pack can also reduce the amount of fuel used to drive the hydraulic components, as most heavy earth moving equipment has a range of modes that can be selected to give the right amount of power while remaining economical. Digging out large amounts of earth will use a lot of power, and this can be increased above the machinery capacity by using a hydraulic power pack. Fine grading of embankments, or excavating over mains power, gas or sewage pipes requires a fine degree of control that is best achieved at a lower power. Hydraulic power packs can help to control this when used in combination with the modes available on the machinery itself. The effect is a reduction in fuel used to generate the hydraulic power and a considerable cost saving over the lifespan of a project.
Because the earth moving equipment uses hydraulics there is no need to employ a separate engineer to maintain and repair the hydraulic power packs as they use the same technology, so there is no extra cost in maintenance terms, just the cost of the power pack. When considering this investment, it is important to understand that the better control leads to improved productivity and workforce morale, as well as a lower outlay on fuel.
Hydraulic power packs are not confined to use in the preparatory stages of a large building project, however, they are also used to work cranes, that lift roof struts into place; in forklifts, that move materials around the site and even in concrete pumping machines, that are used to lay floors and external hard standing surfaces. Hydraproducts are very happy to work with equipment manufacturers to find or design the perfect hydraulic power pack for the construction industry.
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 Power Pack
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