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Our latest blog is a companion to our recently released blog on the rubbish and recycling industry and looks at different ways in which to recycle whilst taking environmental and work space related factors into account.
We look into how hydraulic based solutions can aid in this process to make recycling an easy and efficient process.
Businesses and recycling
One thing that all businesses have in common is recycling. It has become such a common day-to-day task that most people never give it a second thought as they go about their daily duties.
As varying amounts of waste products need recycling dependant on the business, it is essential that businesses review the correct technologies for the job.
Types of recycling technology
Compactors – A popular choice for storing recycled products as they save considerable space compared to other storage methods.
There are various types of compactor available and stationary and self-contained compactors are the two most popular examples. Stationary compactors are typically bolted to the ground and contain an attached received box. The unit is powered by a hydraulic ram which is typically 8’ to 10’ in length and our very own Mini or Standard Hydraulic Power Units up to 11kW are used for these applications. Stationary compactors are usually built using steel to protect them from the elements.
Self-contained compactors usually come in a single piece and are freely moveable from site to site. Due to their good protection against leakages they are normally found in hospitals and food outlets, though one point that goes against this type of compactor is that the storage box is more difficult to replace compared to a stationary compactor, typically taking over an hour to replace.
Balers – Are a good choice for companies who typically recycle over 10 tonnes of waste such as corrugated cardboard as they:
· Maximises the weight of your recyclables by compacting them tightly which saves you haulage costs in
the long run. This includes items such as cardboard, shrink wrap and other plastics
· Helps raise commodity value as you are processing the waste yourself
· Aids in clearing work areas from excess waste materials which in turn raises productivity
It is important to choose the right baler dependant on your recycling needs as it is very easy to over budget on something you won’t be using to its full potential.
There are a number of different types of baler that suit various different businesses and the waste type they need to dispose of. We have highlighted some examples of these below:
· Downstroke Low Profile balers – This type of baler is used if you have a height restriction in your workplace and typically fit a workplace with an 8 foot ceiling. It achieves this by having two parallel cylinders that take on the load.
· Downstroke Vertical balers – These create a small footprint in the workplace with the majority of these units measuring a 5 foot width. They are a good, cost effective option over the typical compactor and if you recycle slightly less waste than average they are the go to option.
· Horizontal balers – These units have a large capacity and can recycle over 25 tons of waste in a typical month. They cost a lot more than Downstroke balers but cut the labour use rate in the recycling process.
So, bearing in mind the examples given above when choosing the best tool for the job, you will need to take space, portability, processing power and cost into account as well as your typical recycling schedule while choosing the best recycling system for your workplace.
During the development of modern hydraulics water was the fluid used most often. Freely available and cheap to acquire, water was the obvious choice. However, as technology moved on mineral oil became the fluid of choice; from the 1920s mineral oils were chosen due to their lubricating nature and higher viscosity than water. Mineral oil also has a much higher boiling point than water, so could be used in applications where heat was an issue for hydraulic machinery using water. Mineral, natural and synthetic oils are still used today as the base for all hydraulic fluids on the market, and ingredients are added to create a range of hydraulic fluids suitable for many different purposes.
It is very important in mechanisms like brakes that the fluid is not hygroscopic, meaning that it will not absorb any water. Braking creates heat, caused by the friction between the callipers and discs. This heat can boil and vaporise any water in the brake fluid, leading to the presence of a vapour in the system that will cause brake failure as that vapour is compressed by the action of the mechanism. It is for this reason that brake fluids are mineral oil or silicone based, and no other type of hydraulic fluid should be used in brakes or other mechanisms where such failure could be catastrophic.
Safety is also a concern in industries where there is a high risk of fire. Hydraulic fluids can be very flammable, but water-glycol and polyol-ester based fluids have naturally fire-resistant properties, meaning they are excellent for use in hydraulic firefighting equipment and other places where high heat, oxygen and combustible materials are routinely used. There is a similar concern for safety in environmental applications, such as agriculture, fish farming and other marine based industries. The failure of a seal or even a small leak in a pipe will cause hydraulic fluid to escape from the system and enter the environment, so it is imperative that biodegradable and non-toxic fluids are used in case of a spillage or leak, as these will not harm the surrounding habitats.
Hydraulic fluids are chosen for the properties that are needed in a specific application. In the examples above fire resistance, biodegradability and hygroscopic properties are very important, but there are several other factors to consider when choosing between fluids. Viscosity and lubricating properties are important in applications where it is not easy to change the fluid regularly (for example sub-aquatic machinery) as the hydraulic fluid also needs to help maintain the mechanisms. Lubricating fluids also have a low tolerance for water ingress so are good for systems where stopping action is just as important as the movement itself.
Aircraft controls use hydraulics to make the transfer of power from the pilots hands to the machinery easier for the pilot; many systems require a large amount of force to operate and this is unsustainable, especially on long flights or in the military. Hydraulic actuators initiate the systems, which are in turn controlled by valves operated by the pilot, flight crew or autopilot. The hydraulic power is generated by the engines and by a backup system that can be deployed in the event of engine failure or during ground maintenance, meaning that even in the event of main engine failure the control systems can still be operated. Aircraft hydraulic fluid must be handled very carefully to avoid contamination, as even a small amount of water or dirt in it could cause catastrophic failure of the systems while the aircraft is in flight. The fluids are checked during every routine maintenance check to ensure they are free from contamination. The types of fluid that can be used on any given aircraft are specified by the manufacturer, and should not be substituted for any other type.
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 .
How well do you really know your hydraulic machine? Do you know what its operating pressure is when it’s running normally? How about its typical temperature? If you don’t know the answer of these two questions, then you don’t know your machine very well and you could be putting yourself into a vulnerable position.
Recently, one of our clients discussed an issue they had with their machine. Although it’s the mobile hydraulic systems that we supply, our clients are involved in all manner of hydraulic machine operations and will often request our input into how to handle certain scenario
Our client told us that he had been having a lot of bother with pump failures. His pumps weren’t even lasting long enough to complete half of the service life that they were expected to fulfill. Of course, our client wanted to know what was going on. He gave us some information about the machine and we looked over his log books for clues as to what could be causing this.
We started at the beginning. We asked him what the normal operating temperature of his machine was. Our client said that he had no idea. So we asked about the usual operating pressure range. Again – he wasn’t sure.
Although the type of machine that our client had displayed this information permanently in the control room, nobody was paying any attention to it. They weren’t reading it or documenting it.
Do you monitor the health of your hydraulic machine by this method? If not, then you should be. It’s important to have a good understanding of your hydraulic machinery.
It’s not difficult information to collect and it’s what will help with analysing any issues with your machine and even giving it some preventative cure options.
How to measure the temperature
If you don’t have an inbuilt thermometer then you might want to use an infrared heat thermometer gun to measure the temperature. Be sure that you use it on the same spot every time. For example, you could put an X on the hydraulic tank, just below the minimum oil level and label it. This will be the position of where your tank oil temperature readings are taken.
Also mark labels for the heat exchanger ins and outs and in two other places that are part of the circuit.
If your system is getting too hot, you’ll have some idea of where this is occurring by being able to measure the temperature on your narked locations.
It really is worth ensuring that you know your hydraulic system well. It will save you time, energy and expense as you are more likely to be able to recognise when an issue is arising and take preventative action.
There are a number of purposes for having hydraulic fluid inside a hydraulic system. Of course, its main purpose is to transfer force from the hydraulic power unit to an actuator. In addition it has to:
Without any of these functions, the entire hydraulic system would not work as well as it should. This leads us to the question of ‘what would prevent any of these functions from fully operating and how can we prevent that from occurring? The biggest threat to hydraulic fluid being compromised is from particles in the fluid.
Although particles may not affect the power of the machinery, the other functions can be compromised by having particles in the fluid. These particles can impact the surface tension of the fluid and encourage microscopic leaks that can become problematic. They can get caught between surfaces that would usually be lubricated. This friction can cause damage and it can also result in an increased temperature of the fluid, which can then go onto cause further damage.
The most effective way to combat particles in hydraulic fluid is to use good quality hydraulic filters that are changed regularly. By keeping the hydraulic filter optimally operational, it’s possible to minimize contamination by the particles, and keep down problems that can occur from it.
What Won’t the Hydraulic Filter Do?
Although hydraulic filters are good, they aren’t perfect. For example, they won’t stop water from getting into the system. If water does get in, it can cause all manner of issues.
However, it’s still wise to equip your system with the best hydraulic filters that you can – the result will be less maintenance and an increased lifespan for your machinery.
In a Hydraulic System, you are most likely aware that the main system pressure is maintained by the system relief valve or even another type of pressure setting device.
The purpose of pressure reducing values is to keep the secondary pressures correct in branches of hydraulic systems.
Most pressure reducing valves are open and 2 way, this allows the pressure to flow freely until they reach further downstream where there is a set pressure. They then shift to throttle the flow in the branch.
Forces from pressure downstream are what actuates pressure reducing valves. This is what will deliver the correct working pressure by enabling a pressure drop to occur in the main spool of the valve. The way that a press-reducing valve works is that it is not a device that is either on or off. In contrast, it delivers a continual adjustment to the pressure. Keep in mind that these types of valves are the most conducive to suffering from contamination when it comes to malfunctioning.
Pressure-reducing valves can go wrong in a number of ways. Again, pressure gauges will need to be installed in order to understand what’s going wrong with one. Once this has been done, you can look for:
· A low pressure at outlet port. If this drops below what it should be, the first action to take is to check the pilot head spool and seat. Check for wear and tear which may be affecting the drain flow. Too much drain flow through this area of the valve will result in reduced pressure and therefore affect performance.
· If you find that the valve will not retain a reduced pressure setting, and the pressure is exceeding it, then check whether the pilot drain line is blocked or affected by contaminants. This will increase pressure which will result in flow to the branch circuit. It’s also possible that the main spool is stuck open due to contaminants blocking it. Again, there could be scoring of either the main spool or bore.
· If you find that you cannot adjust the value to the low pressure setting, even after turning the adjustment knob, then check whether there is wear of the spool or bore. There may even be a broken spring in the pilot head, which will mean not enough force between spool to seat in the control head.
· If there is not enough pressure at the output port, check whether the main spool is stuck in the closed position. This will result in no pressure fluid being unable to flow to the branch. Contaminants could be to blame.
Come on over to our main site for detailed engineering knowledge and info on Hydraulic Systems, we're at www.hydraproducts.co.uk.
Overcentre valves can be described as a type of pilot assisted relief valve, with the only difference between the two being the check valve will open fully when sufficient pressure is applied with pressure in the cylinder port being the only restrictive force, whereas the overcentre valve has to overcome force from the spring mechanism which is reduced by load pressure.
There are 3 main areas of load based functions the overcentre valve provides, which are applicable to both rotary and linear load motion. These areas comprise:
Controlling load – This involves the valve ensuring that the actuator doesn’t run ahead of the pump, thus reducing the risk of cavitation by controlling load induced energy and preventing loss of control.
Ensuring load safety – This safety measure controls movement and ensures that load is under control when a component malfunction occurs, such as a hose failure.
It also ensures that people, equipment and property remain safe when heavy machinery is used, such as a crane with a boom, which has the potential to cause substantial damage if control is lost.
Holding load – Working with the directional valve when it is situated in the neutral position, the load holding function of the overcentre valve prevents any movement of the load and also prevents leakage past the directional valve while it is the closed position.
Pilot ratios explained
When a system is in the design stage, pilot ratios are a main factor that needs to be taken into account as different systems will benefit from different pilot ratios. For example, a system that runs stable, constant loads will normally use a high pilot pressure, while a low, unstable load will benefit from a lower pilot pressure.
The pilot open pressure drop is a good measure of system performance and efficiency, as system pressure typically runs much higher than the pilot pressure needed to open the valve fully.
The two-stage overcentre valve
An addition to the overcentre valve family, the two-stage overcentre valve aims to tackle problems that long unstable booms suffer from, especially those with large capacity cylinders such as telescopic handlers which can suffer from instability issues.
Runaway conditions are encountered in these applications when pilot valves are opened too quickly, due to heavy loads on the cylinder. The two-stage overcentre valve uses two springs with the outer spring being affected by the pilot piston with the inner used as a pressure counterbalance, thus overcoming potential instability issues.
Which type of overcentre valve should you get?
When looking for the correct overcentre valve, you have to ensure you cater for the pressures the hydraulic unit will need to work with. In a system with high back pressure a standard overcentre valve would struggle, as the standard spring chamber is vented to the valve port through the poppet, this increases relief pressure and systems which use a closed centre directional valve would run into difficulties.
Valves are now available that help to combat this problem as the relief sections of these valves are not affected by back pressure and they are identical in every other way to a standard valve.
Finally, some overcentre valves come complete with an atmospheric venting feature, which can be a beneficial feature until they are used in a corrosive type atmosphere which could cause running problems, so it is always important to check system plans and positioning when deciding on the type of valve to go for.
Hydraproducts have a comprehensive selection of valves as part of their new Components Division which can be viewed here.
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