Farm Guide VIC : 2014-15
80 FarmSafety Hydraulic System Safety Pressure, temperature, flammability, mechanical parts and electricity are all factors to consider when working with hydraulic equipment. Pressure With hydraulic fluid under pressure, the following dangers are encountered: • Fluid escaping from a pinhole can be virtually invisible and yet cause serious injury. Avoid touching and even approaching any part of a pressurised hydraulic system. Serious emergencies arise and medical attention is needed when fluid punctures the skin, even if no pain is felt. • Leaking hydraulic fluid is hazardous and it can contaminate the environment. In fact, even a small amount of oil can pollute up to a thousand litres of water. • Hose bursting, whether due to improper selection or damage, can cause injury. If it bursts, you could be burned, cut or injected. • Coupling blow-off can occur if an assembly isn’t properly made or installed. The coupling could come off and hit or spray a person in close proximity, possibly resulting in serious injury. Temperature Most hydraulic systems operate between 65°C and 85°C, but some go as high as 148°C. Liquid at these temperatures, as well as metal parts, can cause burns. Flammability With the exception of those comprised primarily of water, all hydraulic fluids are flammable when exposed to the proper conditions. Leaking pressurised hydraulic fluids may develop a mist or fine spray that can flash or explode upon contact with a source of ignition. Precautions should be taken to eliminate ignition sources, including electrical sparks, open flames, extremely high temperatures, and hot manifolds and engine blocks. Mechanical Swinging arms, booms, rollers, presses, and anything that moves can be dangerous if a hose fails. For example, when a hose bursts, objects supported by fluid pressure may fall, and vehicles or machines may lose their brakes. Electrical Hydraulic equipment must be turned off before it is worked on. With mobile equipment, the key should be removed and/or the battery should be disconnected so that it cannot be started. Abrasion and Contaminants can Lead to Hose Failure A primary cause of hose failure on fluid power equipment is cover abrasions (pictured on the left) resulting from cuts, friction caused by other moving parts or from mechanical impacts. On equipment for example, hoses can change in length while hydraulic mechanisms are in operation, causing a buffeting action to occur and exposing the reinforcement. Exposed hose reinforcement is susceptible to rust and accelerated damage leading to failure. Abrasion-resistant hose covers have been tested and found to last up to 300 times longer than standard rubber covers. This feature increases service life, lowers maintenance and eliminates the need for costly hose protectors such as guards, sleeves and bundling. Contaminants are the natural enemy of hydraulic systems, causing more than 70 per cent of all failures. If not controlled, particles that are too small to be seen can reduce hydraulic system efficiency by as much as 20 per cent. Maintain hydraulics on farming equipment by ensuring contaminants from the environment, contaminated hydraulic fluid and system wear contamination are kept out of the hydraulic hose. Contamination affects hydraulic systems in many ways: • Corrosion of hydraulic systems from acids that form due to fluid breakdown and mixing of incompatible fluids in the system. • Increased internal leakage that lowers the efficiency of pumps, motors, and cylinders. It decreases the ability of valves to control flow and pressure accurately. It also wastes horsepower and generates excess heat. • Sticking of parts due to sludge or silting. Silting is a collection of fine particles in critical areas, which will impair proper system operation. • Seizure of parts or components caused by large amounts of contaminants getting stuck in the clearances. In addition to the factors above, hose assembly and installation are all critical to ensuring the safe operation of hydraulic systems. Quality hydraulic products will offer trouble-free and long-lasting service in the most demanding working conditions of farming machinery with hose and fittings covering a multitude of applications on combine harvesters and tractors. Article su pplied by Gates. Contact Southcott, a distributor of Gates hydraulics solutions, for f urther information or visit w w w.sou thcott.com.au.