Originally appeared in TecTorque Summer 2016
High-pressure (700 bar) hydraulic tools pack more force into a lighter and more ergonomic package for tasks such as lifting, positioning, pulling, pushing, spreading, clamping, holding, bending, straightening, forming, bolting, fabricating and maintenance. The very simplicity of such tools can, however, often lead to their abuse and it is often difficult to comprehend the tremendous forces that are generated with a minimum of input from the user.
But where the proper rules and disciples are observed, hydraulic power is also one of the safest methods of applying force – and some of the most common mistakes are the simplest to rectify, according to high-force hydraulics specialist and Blackwoods partner Enerpac.
Rule 1 – Get the basics right When working on hydraulic cylinder applications it is important to apply pressure or lift slowly, and to always regularly check the load. Anticipate possible problems and take steps to avoid them, and above all think about safety and avoid standing in the line of force.
Rule 2 – Dress for the job Always wear personal protective equipment (PPE) such as safety glasses, a hard hat, gloves, safety shoes or boots, and other protective clothing relevant to the particular site conditions. Get into the safety habit before you lay a hand on a hydraulic tool.
Rule 3 – Look first Always perform a visual inspection and identify all equipment before starting the job. Everyone needs to be aware of what tools they’re working with. This visual inspection will also allow you to determine whether there are any missing parts that will be necessary before the job begins.
Part of the visual inspection should be to check that your equipment is functional. All leaks and failures should be tagged out and it is important that a gauge is properly fitted to the system.
Rule 4 – Check your set-up Most problems encountered in a hydraulic system are the result of improper assembly or operation. Read all instructions carefully and, before you use any hydraulic equipment, be sure you know what its function is and how it works. Position the load on firm, flat ground and if possible, use a jacking base. This prevents the load from ‘kicking out’ or the reaction force punching a hole in the floor – an embarrassing and potentially expensive situation best avoided.
The two greatest enemies of hydraulics are heat and dirt. Keep oil connections clean, and use dust caps to keep dirt out. Heat above 65°C will soften packings and weaken hoses. If it is necessary to use heat, shield the cylinder with a blanket or a piece of sheet metal to deflect the heat.
Make sure you use a saddle, otherwise the plunger will mushroom. When fitting a saddle into the end of the plunger, ensure that the face of the saddle is hard up against the face of the plunger. Cylinder mounting threads should always be fitted with thread protectors, otherwise damage to the thread will weaken it and reduce its capacity to withstand the reactive force of the cylinder.
Rule 5 – Appropriate use and maintenance As well as lifting slowly and regularly checking the lift, never attempt to lift a load that exceeds the capacity of your system. Overloading damages cylinders, blows seals, and bends plungers. As a general rule of thumb, estimate the load and then double it. If 10 tons is estimated and a 10 ton cylinder is used, ‘you’ are working to generate the pressure. Instead use a 20 ton cylinder and let the ‘area’ do the work. Use a gauge to indicate safe operating loads and pressure levels. Before advancing or retracting a cylinder, make sure the area is clear.
Using products to their maximum, repeatedly, will lead to premature failure. Just as you don’t drive your car to its maximum, if you could, then build some safety into your hydraulics and follow the 80 per cent rule. Leaving 20 per cent of the plunger inside the base will give greater stability and using it at 80 per cent of rated load capacity means that pumping is not as difficult. Do not use an extension on the pump handle. The use of an extension could tip the pump forward and jam and damage your knuckles. It can also make the pump become unstable or pressurised beyond its safe limits.
Hydraulic systems are designed to use hydraulic oil only. Follow the manufacturer’s recommendations, as the incorrect oil will damage the system and make it unsafe to use. Just like a car, it needs to be changed in order to ensure the oil is in good condition.
When you are finished, release the pressure gently. Releasing the pressure in a system suddenly will cause the needle to snap back – throwing the gauge out of calibration. Use a snubber valve to prevent this happening. The snubber valve will also dampen out any pressure fluctuations thus giving a more accurate, easy to read pressure or force indication. Before storing hydraulic equipment, make sure it has been properly cleaned and lubricated where necessary. This will ensure its longevity and efficient functioning over the long term.
Rule 6 – Right tool for the right job There is no shortage of hydraulic equipment available so it is important to seek expert guidance on which products best suit the task at hand, and the safest way to operate them. For example, time-consuming, labour-intensive manual tasks such as bolt tightening can be performed with ease using a torque wrench. Torque wrenches are some of the safest and most reliable non-impact fastening technologies available – a whole generation ahead of methods such as flogging wrenches, for example.
However, like any powerful precision tool, they need to be operated properly and with respect for their capabilities to get the best out of them over the longest time. Pump selection is also important, as a lot of tools are actuated by hydraulic pumps. Selection of the correct type of pump is critical to the efficiency and safety of the powerful and portable hydraulic tools that are increasingly being relied upon for jobs that once involved backbreaking and hazardous manual labour.
Traditionally, users of hydraulic tools have been able to choose from three main pump power methods: hand, air, or electric. Each power source offers distinct advantages. Electric and air-powered pumps offer plenty of power, but they must be connected to an available power supply by cords or hoses.
Hand and battery-operated pumps offer flexibility and portability, but operator fatigue and battery life can restrict the size of job they can handle. Other factors, such as purchase price, running costs, anticipated service life, worker training, employee safety, type and frequency of chores, and tool duty cycle, must also be taken into consideration.
Rule 7 – Hose management The hose is one of the most delicate parts of a hydraulic pump, yet it is essential to its functioning. Always leave some slack in the hose. As hoses pressurise, they shorten and if there is no slack, the hose will pull out of the end fittings. Never place the hose directly below your load, and make sure it is well clear of other objects. Dropping heavy objects on it will lead to hose failure. Also avoid sharp bends in the hose as the pump, never by the hose and never hold the hose when it is under pressure. This would strain the hose and excessive strain will cause the braids to fracture or pull out of the crimp, causing leaks.
Rule 8 – Use genuine parts Quality hydraulic tools have been precisely engineered for optimum performance, safety, and efficiency. Although cheaper at first, using a part that has not been designed for the system could cause the whole thing to fail, which not only jeopardises the operator’s safety, but costs significantly more in replacement and damage.
Rule 9 – Use authorised repair agents Hydraulic tools need proper care and maintenance in order to function at optimum efficiency. Authorised repair agents have been fully trained in the technology in question and have the necessary qualifications and experience to service the tools. To ensure the tools remain safe, only these agents should be used for service, maintenance and repair of tools.
Rule 10 – Learn about safety Manufacturers – including Enerpac – run safety courses and training initiatives designed to keep industry professionals up-to-date with the latest safety practices. Take advantage of these courses and the opportunity to learn more about hydraulic safety.
Equally input from customers is fundamental to the design, development, production, and supply of standard and custom-made hydraulic solutions for the safe, precise control of movement and positioning of heavy loads. It’s a true knowledge partnership, and you have a part to play.
The selection of the correct size cylinder, the right pump to operate it, the right choice of accessory equipment, together with the careful observance of some simple safety rules, and you will add the value of safety to the power and convenience of high pressure tools.