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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.
Our hydraulic power units are used in a variety of different situations. Sometimes they are required to be operated in potentially explosive atmospheres.
At the heart of every hydraulic system is a power unit. It needs to be reliable and be capable of performing the job at hand. We design each of our power packs to be cost effective, reliable solutions. They are application-specific to complement our cylinders.
Most of our hydraulic power pack units are built from stainless steel, steel or aluminium and can hold a volume of no more than 2000 litres. Whatever the load is that you need to handle, we can provide you with the right unit.
In addition to our power packs, we can supply items such as extra oil trays that can collect to protect the environment, noise-reduction casings and canopies that are weatherproof.
Contact us and let us know of the specifications required on your power pack, and we can support you in meeting your requirements.
Depending on what your load is and where your equipment is located, we can even equip our power units with an integrated cooling system complete with water, oil or heat exchanges.
Our valve blocks are known for being extremely accurate and therefore enabling a fast precision finish even when a volume flow rate of 750 litres per minute is in use.
With every system that we supply, we provide system-specific data sheets and fully comprehensive documentation. Whether it’s an ATEX certified unit or not we can provide you with certification and inspections as required.
Whatever you are looking for in terms of a hydraulic power unit, know that our range are designed by our engineers to provide you with a smart solution to your needs. Contact us today to discuss your requirements.
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.
ATEX ratings refer to the ability of a piece of equipment, or the design and use of a particular space, to withstand the effects of an explosion. The name ATEX comes from the French words Atmospheres Explosibles. There are two EU directives governing explosive atmospheres, one for manufacturers of equipment and one for employers who are responsible for the health and safety of staff working in such an environment. The definition of an explosive atmosphere, as laid out by DSEAR (The Dangerous Substances and Explosive Atmospheres Regulations 2002) is: “a mixture of dangerous substances with air, under atmospheric conditions, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads to the entire unburned mixture”. This is really just a way of describing the conditions typically found in a mining environment, a vehicle spraying facility or even a sawmill where dust, paint particles and mist or gases are commonly found.
ATEX ratings classify these types of environment into two groups, I and II. Group I is for mining industries, and group II covers all others. Within group I there are subsets for environments where the equipment will be energized when an explosive atmosphere is presents (M1) and for when it will be de-energized (M2). Group II is divided further into three categories based on how often an explosive atmosphere will be present, and how long it will last for under normal operating conditions. Subdivisions for gases and dust are also used to denote the potentially ignition source.
Specialised hydraulically powered machinery for use in places such as mines, sawmills, vehicle spraying facilities and the like, needs to be rated for use in a potentially explosive atmosphere. These ATEX ratings will appear on a label with a hexagonal symbol containing the letters “Ex” followed by a series of letters and numbers, which denote the subsets for frequency of the explosive atmosphere and the ignition source. Some machinery may be rated for use in two types of environment, such as on the boundary between two such places.
ATEX ratings are vital to industries where there is an explosion risk due to the environment and nature of the business. Without them it would be impossible to reliably tell which equipment is safe for use in these places, so the ratings give peace of mind to those purchasing or working with the machinery. As hydraulically powered machinery is frequently used in mining industries, as well as processing and manufacturing of potentially hazardous materials, it is vital that it is all tested and certified correctly to avoid accidents. At Hydraproducts we know how important health and safety is, so you can be sure then when purchasing ATEX rated equipment from us, that you are in safe hands.
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.
Low-cost manufacturing of hydraulic systems has become far more common since China entered the marketplace. In fact, the nation has taken the top spot when it comes to their factories in this field.
The reason for this is the fact that these machines are usually big ticket items, so making a good cost saving up front will also be appealing. However, most people will be aware that although you’ll gain on the saving initially, will you still gain over the lifespan of the machine when it comes to maintenance, reliability and at what risk?
Making a saving on the initial cost isn’t always the most important part of the purchase. The cost of it over the span of its life will be what counts in the end. This means that consideration beyond now is necessary. To come to a conclusion, take the capital cost of it and add on the cost of maintaining your hydraulic system’s good health over the length of its life.
Although it’s easy to get the figure for the capital cost, the operating cost of it over its lifetime is not as easy to calculate.
Here at Hydraproducts we often promote the concept of proactive maintenance, as we know what a difference it makes to not only the reliability of a hydraulic system, but also the cost of owning it. Of course there is time and expenditure involved in maintenance, and this of course has its own related costs.
As China continues to make inroads into the hydraulic systems sales market of the West, their sales strategy is based around price and that initial expenditure will always appeal to a large number of owners. Most of us can think of somebody we know who has opted for this route vs a more traditional European manufactured hydraulic system.
Something to take note of is that the Chinese usually imitate. They are not always good at doing this either. Of course, the quality of the components that they use will make a difference with regards to how reliable their machines are. When they build their systems, it will also depend on whether the components come from a well-respected manufacturing outfit or a run of the mill ‘me too’ factory set up quickly.
Meanwhile, over in the Western world, there’s usually a balance in play between cost and reliability with all hydraulic system manufacturing. This isn’t the case in China. Those who opt to buy from the Chinese are often forced along a painful learning curve which involves witnessing the questionable quality of components and design, in addition to sometimes witnessing an early demise.
We’ve all seen products coming out of China that aren’t sophisticated. How can these go wrong when they are reliant on the simplest of designs and components? But as soon as things get complicated and there are more things that could break, things get sticky.
Potential hydraulic system owners may make their buying decision on the fact that the cost of a Chinese built hydraulic system may be less than half than the price of a Western one. It may last over half as long. In which case the economics don’t seem so bad.
But if it costs half of the price but it only lasts for a quarter of the time, then that’s not going to work out too good in the books. So how do you work out how long it will last? That’s the problem – you can’t. There are too many variables involved. If you pay 50% of the price, or even 25% of the price, you surely cannot expect it to deliver the same level of performance or to have the same lifespan as the machine that you paid Western prices for.
Although there could be some good deals out there with some happy endings, it’s critical that the buyer knows what he’s doing. There are also safety matters to consider in addition to the economic benefits when it comes to maintaining your hydraulic system over time.
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 .
Hydraulic Power Pack
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