Hydraulic oil, also known as hydraulic fluid can be either synthetic based or mineral based. Hydraulic oil is a non-compressible fluid that is used to transfer power within hydraulic machinery and hydraulic equipment. More commonly used in the process of transferring power within hydraulic equipment, hydraulic oil can also be used as a sealant, coolant and also as a lubricator in hydraulic equipment.
The main differences between synthetic hydraulic oil and a mineral based hydraulic oil are that mineral hydraulic oils are derived from crude oil whereas synthetic hydraulic oil is manufactured in a lab.
Hydraulic fluid is the medium by which energy is transferred to all hydraulic systems. However, the tasks performed by hydraulic fluid go much further than the transfer of power. Although it is the core purpose of hydraulic fluid, it is also valuable in four secondary functions: transferring heat, removing contaminants, sealing and lubrication.
Transferring Heat
Hydraulic machines produce a huge amount of additional heat during regular operations, often caused by the components themselves, such as pumps and motors. Without a way to carry heat away from these components, they could easily overheat which could result in damage to seals and internal components. As engine oil makes its way back to the reservoir, it often travels through a cooler to help maintain optimum temperature ranges before it is pumped back out to the system. Equally, hydraulic fluid can carry heat into a system during cold starts, when needed.
Removing Contaminants
If hydraulic systems with closed-loops didn’t bleed off fluid at a precise rate, contamination would quickly build to critical and harmful levels. Due to the damage heat can cause, it can be considered a form of contamination, but as well as transferring heat, hydraulic fluid also carries particles and water away from sensitive components through filters or other conditioning devices. This can then be cleaned up and returned to the circuit. Oil without a driving force would remain within sensitive components, allowing essentially trapped contamination to slowly destroy its surroundings.
Sealing
Although most would consider hydraulic oil as being a fluid that the pieces of hardware seal against, hydraulic fluid (especially oil) actually provides sealing within areas such as pumps, valves, and motors. For example, a spool valve has a seal at each end that stops oil from escaping the valve, but each notch on the spool is sealed from the adjacent cavities by only the tight metal-to-metal tolerances and the oil’s surface tension and resistance to shearing.
Lubrication
Lubrication is needed in the majority of hydraulic components to protect internal parts from wearing or damage as a result of metal-to-metal friction. Oil provides full-film lubrication between moving parts, such as the slippers and lens plate of a piston pump. Without the lubricating properties of the oil, hydraulic systems would be incredibly inefficient and unreliable.
Hydraulic oil is made with other important properties, but these tend to be common regardless of brand, viscosity or application. Hydraulic oil has a package of chemical additives for helping the performance of both the oil and the components of the hydraulic system. These additives can improve a number of functions including the foaming resistance of the oil, corrosion/rust resistance, and the water-retention properties. The additive package separates low and high-quality fluids, and additives will also improve the viscous properties of the oil.
Hydraulic fluid is the life-blood of many mobile and stationary machines. It is difficult to overemphasize the care that should be taken to maintain this precious medium. It is equally important to remember that while a quality fluid has been engineered and designed to perform challenging tasks, it cannot compensate for a system with an undersized reservoir or a motor with an excessive shaft load. If the hydraulic components are properly specified and the overall system is well designed, a good quality hydraulic fluid will serve the critical function that ties the pump and the actuator together, along with all components in between.
Enfields Oil supplies the latest high-performance hydraulic oil. This general purpose hydraulic is oil designed for use in a broad range of applications including vane and piston pumps. This high-quality hydraulic oil is manufactured from solvent refined, high viscosity index base oils, incorporating modern additive technology. To find out more, contact Enfields Oil today!
