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How do I operate this piece of machinery correctly and safely? A question often asked by new team members or workers unfamiliar with new equipment.
This blog focuses on the safety aspects of working with open top tipping bodies and the importance of operators following set rules to ensure that correct safety protocols are followed.
Accidents and injuries related to tipping applications are all too common and can start from a simple operator mistake to operating guidelines not being followed correctly, ending in injury to the driver or others.
It is essential that operators of tipping applications are briefed on and trained on how to use the equipment correctly and know the necessary steps to take should a malfunction with the tipper hydraulics or other system related problem occur, as well as how to avoid potential accidents.
The most common occurrences of accidents are the vehicle rolling over sideways or striking an obstruction. The effects of these could be very serious and potentially fatal.
Below, we examine the steps from the initial loading of materials onto the tipper to unloading at the destination and guide you through the correct procedures to be followed to avoid any incidents and accidents.
Correct Loading procedure
Following the correct loading procedure for materials is imperative to avoid any pitfalls further down the line. Firstly, the load should be evenly distributed in the trailer to keep the balance equal should any secondary factors come into play such as flat tyres, sloping ground etc. which could promote tippage.
Incorrect and uneven distribution of load could also put stress on vehicle systems, such as suspension or lead to axle overload. It could also cause issues when the tipper is unloading at its destination, potentially making the vehicle unstable.
During the journey
Once you are happy that the load is sitting correctly on the tipper and have begun your journey, there are a number of key rules to follow to ensure your load is transported safely. A major safety concern is the type of terrain you will be travelling on. If possible try to avoid overly soft ground and steep gradients, as well as areas of road that have been previously excavated or poorly repaired.
It is also important, depending on where you are travelling, to follow the local compliance and legislative laws, as well as any weight limits that are imposed on your tipper or the route you are travelling.
At the destination
On approaching your delivery destination you should first identify a suitable area which will be used for unloading your goods. Bear in mind safety aspects such as overhanging electrical cables, which may hamper the unloading process or uneven ground that could prove to be a safety hazard.
Another useful safety measure you can take is to fit a rear facing camera to the back of the vehicle which gives a clear indication as to what is immediately behind you when you begin the unloading process.
Make sure nobody is standing adjacent to the vehicle when unloading is taking place, as a number of potential accidents could happen including the swinging of the tailboard and a load that releases quickly and catches an unsuspecting person off guard.
Finally, maintaining the right rate of discharge is key when unloading your materials and the person manning the vehicle should monitor this at all times, as different materials will require different discharge rates.
Vehicle check after unloading
Once you have successfully unloaded your goods and before you leave the site the vehicle should be checked for damage and general cleanliness, to ensure that there are no blockages from stray debris etc. and no damage has been done to the hydraulic mechanism or system components related to the unloading process.
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 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.
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.
In our latest blog we take a look at desiccant breathers and explain why they are used and how they work to maximise the efficiency of a hydraulic units breathing system.
The desiccant breathers main role is to protect a power units breathing system and filter out moisture and contaminants drawn in from the working environment, thus helping to prolong the life and efficiency of the power unit.
How does it work? – The desiccant breather unit contains silicone based gel which helps prevent particulate entering the system during operation. They also work to soak up any moisture that is in the system while it is in shut down or during a service period.
In environments where there are high ambient levels of humidity, such as offshore oil rigs, optional breathers with check valves are available which come in the necessary fitments for most power units.
Where is it fitted? – The desiccant breather replaces the unit’s standard OEM breather cap, coming in a screw-on fitment and in a number of different sizes depending on your type of hydraulic system.
How do I make sure I choose the right filter? – Many leading suppliers of desiccant breathers have product configurators on their site so you can choose from a number of crucial variables that are tailored to your system:
Airflow - which typically varies from 0-27CFM, giving a good pointer as to the amount of air that typically passes through the breather system during operation
Unit dimensions – Including height and diameter measurements to ensure the breather fits the unit without coming into contact with other parts or compromising unit space
Amount of silica gel needed – This is largely dependent on the size of the system and working environment as to how much silica gel is needed to stop particulate contamination and excess moisture accumulation
Absorption capacity – typically measured in fluid ounces, this capacity can change due to the nature of the application and the environment it is situated in
Operating temp – The filters are built to withstand large temperature fluctuations, so it is common to see operating temperatures range from around -40°C to 149°C which covers a wide range of operational and environmental conditions
Filter efficiency – An average sized desiccate breather is able to achieve in the region of 0.3µ absolute (β₀.₃≥200) efficiency under normal operating conditions.
Build quality – As technology is constantly evolving, filters are being built to withstand obstacles such as unit vibration and impact protection, and constant development is enabling filters to withstand harsher environments and temperature changes (as detailed above) with stringent product testing taking place.
With bespoke hydraulic units that use these breathers on applications such as offshore oil rigs, where humidity and other factors can potentially hamper a unit’s performance, it is imperative that the breather unit can tackle these obstacles in an effective manner.
Connections – Desiccant breather filters typically use a UN female thread to connect to a power unit with various sizes of this connection being available dependent on application.
At Hydraproducts we frequently rely on the efficiency and reliability of desiccate breather filters for our bespoke offshore power units. So feel free to contact us to learn more.
If you’ve been acquainted with us for some time, you’ll know already be aware that we design and manufacture hydraulic systems however, we are mostly focused on the mobile hydraulic power packs. We have the facilities to test our products to ensure that they are tweaked to deliver the best possible performance under a wide range of circumstances. Although having the right facilities does help us with the development of new products, the greatest power that we have is the minds of our engineers.
What makes a great engineer? Is it their brilliance at technical matters?
Their determination to make things work? Well add both of these talents to passion and you’ll be on the right track. The minds of our engineers are able to create new answers to our hydraulic system questions – and they’ve got a whole truck load of wit to go along with their deliveries. Our engineers work hard to develop products that they know solve power challenges for our customers. They are resourceful when it comes to blending engineering tricks with the need to keep to the regulations of our industry and safety considerations.
It’s not just anybody who can thrive in this type of role. We suspect that our engineers were playing with Lego at the age of two in their quest to build (and knowing 2 year old, destroy) and they no doubt evolved into using Fischer Technic and Meccano to build their dream designs.
Now that our hydraulic engineers are operating on real work projects and applying lessons learned from the deep knowledge they’ve acquired around hydraulic system design, they are really flourishing in their development.
Taking valves and pipe mounts to create products that will last longer and be more dependable takes a lot of thinking. When working with clients who are in unfamiliar territory, it can be challenging for any engineer. Oftentimes, the customer won’t have a mathematical or design mind, and specification setting can be an area that is not easy.
However, if you’re looking to solve issues and you want to get it right, you may want to take the time to work with a hydraulic power pack manufacturer such as us.
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