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In the mobile hydraulic industry there are a wide range of safety and conformity regulations that should be adhered to for both safety and product performance and reliability.
The E Mark is an ECE mark to designate approved vehicles and vehicle components sold in the EU.
The E11 Mark is the British specific Mark that covers equipment/vehicles supplied to the automotive industry. This includes commercial vehicles, construction machinery and general vehicle use and basically means the unit has been approved by ECU compliance and quality control regulations.
The E Mark number differs dependent on which country the product inspection had taken place in. So, Germany for example uses the E1 Mark while Turkey uses the E37 Mark.
When businesses buy new products they expect that product to live up to expectations and do what it is claimed to do. When dealing with DC hydraulic power packs this is crucial as the safety implications of such a unit failing when in use could be catastrophic and cost a business dearly.
To achieve the E11 status in the UK, a DC hydraulic power pack product must meet EMC standards. To certify this is the case an approved test house must be engaged to carry out and verify compliance. As well as this a COP must be in place, this is essentially a quality control plan to ensure all future manufacturing is done to the same standard. This is externally verified periodically.
The E Mark system was implemented in the 2004/104/EC directive for the regulated movement of electronic goods used for motor vehicles around Europe.
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 .
Although there has recently been a change to the political standing of the UK with regards to its membership of the European Union, it’s likely that all regulations will stay in place for the foreseeable future.
What is ATEX?
ATEX is an acronym for the French term ‘ATmosphers EXplosives’. It covers the certification of equipment that is used in a hazardous area. The EU directive 94/9/EC requires that any electronic or electrical equipment is used within a hazardous area, it is compulsory that it has an ATEX certificate.
When there is a potentially explosive combination of flammable gasses, dust or air in an area, then this is classified as a hazardous area. This is something that also addressed outside of the EU area by the IECEX certification system. In North America the UL system is used and equipment that are suited to use in hazardous atmospheres are required to be labelled as such.
Considering hazardous areas and the likelihood of the presence of a potentially explosive atmospheres, the European, IECEX and the North American method all use a classification system for areas with gases and dusts.
in accordance with the ATEX directive
For use in underground mines
For use in all other places
Equipment that is intended for use in areas where an explosive atmosphere is present continuously, for long periods or frequently
Equipment that is intended for use in areas where an explosive atmosphere is likely to occur in normal operation and must ensure a high level of protection.
Equipment that is intended for use in areas where an explosive atmosphere is unlikely to occur in normal operation and must ensure a normal level of protection.
Gas / Dust
Equipment certified for use in flammable gases
Equipment certified for use where dust is present in the atmosphere
Type of Protection*
Surface above ground industries
Gas Sub Group
Less easily ignited gases e.g. propane
Easily ignited gases e.g ethylene
Most easily ignited e.g. hydrogen or acetylene
Hazardous area apparatus is classified according to the maximum surface temperature produced under fault conditions at an ambient temperature of 40°C, or as otherwise specified. The standard classifications are as shown
* There are 8 methods of protection, for simplicity we have listed the 3 most commonly used.
An ATEX approved electrical product is marked with the following code:
II 2G Eexd IIB T4
From the breakdown of the code below it can be seen that the product is flameproof, suitable for use in zone 1 surface applications where gas group B gases may be present and the surface temperature of the product under fault conditions will not exceed 135 ºC.
Explosion proof in accordance with ATEX
Equipment group: II surface industries.
Category: 2 equipment (suitable for use in Zone 1)
Gas / Dust: Suitable for atmospheres containing gas
European certificate in accordance with harmonised standards
Explosion-proof electrical equipment
Type of protection is ‘Flameproof enclosure’
Gas Group II – surface industries
Gas sub group = B
Temperature class T4
Please note: This information is provided as current at time of publishing. We are not responsible for any use of it. Seek expert guidance prior to servicing, using or classifying any equipment that might be used in a potentially explosive atmosphere.
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.
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