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When you decide to change your hydraulic oil, you need to know that although you will have attempted to drain all of it, it won’t all have left the system. It’s for this reason that you need to ensure that your previous oil is going to be compatible with the new one.
Here at Hydraproducts, we use a number of different oils when we test both our bespoke and non-bespoke mobile hydraulic systems. We follow the process below to ensure that it’s changed under controlled conditions:
This process, although sometimes run through up to 4 times, will eventually whittle down the previous oil so that there is eventually more than 95% of new oil in the system.
1. You’re going to get through a lot of oil
2. If there is a 95/5 mix ratio of the old and new oil, they will still need to be compatible
If you don’t want to get through all that oil, you could try mixing your oils beforehand using a 75/25 mix and give it a good shake, wait and observe or even put the blend in a temperature controlled zone for one month. The temperature should of course be in line with your operating temperature/climate so that you can see what might happen. You could then examine the blend to look for incompatibilities.
However, if you go ahead and opt not to do this test, you could regret it when your machine suffers as a result. Compatible hydraulic oils are key to the performance and reliability of your system.
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 .
We are big fans of scheduling as we know what a difference it makes to the condition of a machine. For example, a hydraulic pump that is regularly serviced should still not be allowed to continue to perform beyond its expected service life. Although you may not notice that the rate of productivity has changed, once a pump begins to gain a certain age, it can put your entire hydraulic circuit and components at risk if it’s not changed out.
A hydraulic pump that is part of a service and maintenance schedule has a good chance of operating in a high performance manner. However, the chance of it failing whilst in service is much increased.
The problem with a component failure occurring during service is that it will usually make a mess, ie a vast number of metallic particles are going to be on the loose in your system. They will cause devastating damage as they roam around in your hydraulic fluid prior to being caught by your hydraulic filters. Even worse, they may even be so numerous as to clog your filter and then you’ll have unfiltered fluid circulating throughout the entire system.
Any component that fails whilst in service will no doubt be far more costly to fix than one that is withdrawn from service prior to failing. This is due to a failure most often causing damage inside the component. It can also cause damage throughout your system affecting many other components. Parts of the component that would have been relatively inexpensive to repair now have to be replaced.
Any sliver of your broken down component may make its way to another component such as a cylinder and cause no end of trouble. If you remove pumps as part of a schedule change out system, then you can save yourself needless downtime and needless expense.
If you’re new to our blog, then you should know that our vocation is in designing and manufacturing mobile hydraulic equipment for all sectors, including subsea hydraulics. However, we do like to pass comment on all aspects of hydraulics. If you’re looking for a mobile hydraulics solution, feel free to give us a call to discuss your needs.
Although there are still, to some degree, mixed messages being sent about climate change, the weather does appear to be changing. We are seeing an increase in the incidence of extreme weather across the globe.
Surprisingly, this is an area of concern that can affect businesses or individuals who run hydraulic equipment. Those in the design and manufacturing arenas need to consider that machines may need to start in cooler temperatures and may need to run in hotter conditions.
More hydraulic equipment owners could find themselves needing to operate in temperature extremes for which their machines were not designed. This will impact the reliability and lifespan of the machines.
Due to the behaviour of hydraulic oil that is petroleum based, it’s important to consider how greater and lower temperatures affect viscosity.
With oil viscosity being greater in cooler temperatures, there is more chance for the system components to be damaged through cavitation. If the temperature goes so low as to drop more than that oil’s pour weight then there could be pressure intensification that causes damage to hydraulic cylinders.
There is also the issue of loss of lubrication with low oil viscosity. The lubricating film is less strong and without that operating at optimal strength, there’s more chance of damage and scratching.
Oil temperature could be controlled by keeping a close eye on it and by adding cooling capacity and protection for cold starts to cope with unexpected change in climate.
With overall efficiency being usually less than 80% of any hydraulic system, it’s likely that it will need a heat exchanger to help matters. However, they can take up a lot of room and are expensive to buy, which can often mean that they end up being too small for the job.
In a warming world, it’s better to have too much cooling capacity.
In summary, it’s important to recognise that climate change will affect how hydraulic systems operate and to proactively prepare to manage this.
Changing the filter element in your hydraulic machinery is a very important part of routine maintenance and for this reason it is often tacked onto a schedule and done at a set time, usually determined by the number of hours it has been in service for. Changing filter elements, wherever they are situated in the hydraulic loop, needs to be done in order to keep the fluid as clean as possible to therefore prolong the life of the components in the system, however, getting the timing right to ensure you are making the most of your expensive filter elements is a more intricate art than simply totting up the service hours and basing a filter change schedule on that data alone.
If a filter element is changed early it will still have plenty of dirt holding capacity left, and to replace one with life left in it is a false economy – yes, you will not run the risk of leaving it too late and potentially allowing contaminants into the oil, but it is also a waste of resources. Leaving an element change too late means that dirt can enter the system and cause damage to the components, leading to machine failure and spiralling associated repair costs. If we cannot use service hours to inform the timing of a filter change, how can we tell when is the right time for a switch?
The location of the filter can make a difference to the regularity of the element changes, as pressure filtration systems work a lot harder than off line or return filter systems. They are often higher in initial cost as well as in ongoing maintenance costs, but offer a fine level of cleansing as they can trap the smallest particles, thanks to the pressure forcing the fluid through the filter. The same pressure can dislodge trapped dirt, sending it back into the machinery and causing damage, so there are also downsides to using this location for hydraulic fluid filtration. Off line filtration systems are also very expensive but are the most effective at filtering, as they run continuously and therefore offer the best extension of machinery life. They also require regular replacement of the filter elements, as they are active for much longer than a filter that is only operational while the machinery is running. Return filtration is the most popular and most economical location for filtering hydraulic fluid within a system and also offers the opportunity to filter new oil in via the same part of the loop.
The best way of knowing when a filter element needs to be changed is to monitor the pressure drop across the filter, with a marked drop in pressure on the downstream side indicating that the dirt holding capacity is almost used up. A clogging indicator is one way of measuring the pressure drop and this can be used when it is suspected that the time may be approaching. Clogging indicators can be visual or electronic and set to go off before the pressure for the filter bypass valve is reached. Not all hydraulic systems have a filter bypass, but those that do can link the associated pressure point to the point at which a clogging indicator is activated.
A more sophisticated system involves continually monitoring the pressure drop across the filter, wherever it is located, and the resulting data can be used to inform a more reasonable and reliable filter element change schedule, as it shows the true lifespan of the filter elements. The data also acts as an early warning system of system or component failure. Although an advance continuous monitoring system costs more, in the long run it will save money on unnecessary filter changes, warn of expensive system failure before it happens and provide valuable information about the operating capacity of your hydraulic equipment that could prove a lot more valuable in the long run, and just think - all these benefits can arise from simply trying to work out a proper filter element replacement schedule!
Hydraulic pumps, one of the more common mechanical applications of hydraulic technology, use fluid to push an arm a set distance forwards and backwards (or up and down). One example is the mechanical arms of a digger or other ground-working machinery. A hydraulic pump is perfect for this use, as the machinery works using the set distances between the components of the arms.
A hydraulic gear motor uses fluid to power movement for a much longer distance (or to put it another way, for an unspecified length of time). The motor works by running fluid through a chamber containing two cogs. One is linked to the drive shaft and transfers the power to the component that needs to move, and the other is idle, existing only to complete the mechanism. The same fluid is pumped through the motor chamber for as long as the power is needed, and it works in a similar fashion to an electric motor, but is much smaller and can be used in places where electricity is not safe or viable to use. It is a natural development of the waterwheel that was commonplace in the UK during the Industrial Revolution, powering cotton mills, woodworking and even bellows for blacksmiths forges.
A hydraulic gear motor is more appropriate than a pump for any piece of machinery that needs continuous power in a simple mechanism; a series of hydraulic pumps, arms and cogs can be used to create continuous power, but the resulting apparatus is bulky and made up of several components, which increases the likelihood of mechanical failure. A hydraulic motor, by comparison, can be very small and portable, meaning it is ideal for any application that is a long distance from traditional power sources and remote areas of the planet where other forms of energy are not viable. They are also reasonably simple in construction, so parts and maintenance are not an issue.
Hydraulic motors are ideal for use underwater and in dangerous places like mines and gas works, where the spark from an electric or petrol motor poses a serious fire risk. They are also good for any task where the motor is operated remotely, as the fluid can be pumped a long distance to the motor using comparatively little power and the only connection needed is piping, compared to more expensive electrical cable for running a remote electric motor. What is the most ingenious application of a hydraulic motor you have ever seen? Let us know in the comments below.
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