What is Hydraulic Fluid and How is it Used in Construction Equipment?
What is Hydraulic Fluid and How is it Used in Construction Equipment?
Reading time: 5 min 30 sec
Introduction to Hydraulic Fluid
Hydraulic fluid is one of the many important fluids essential to modern heavy equipment. Almost all construction vehicles and equipment use hydraulic fluid to carry out their core functions.
A hydraulic system runs on the principle of fluid power, where a pressurized fluid transmits force throughout a closed system, in turn providing power to various components. Such a system enhances machine performance by providing incredible power-to-size ratios with a high degree of precision.
Therefore, the role of hydraulic fluid in construction equipment cannot be overstated. In this overview, we’ll provide you with an introduction to hydraulic fluid, helping you understand the key role it plays in your equipment.
Understanding Hydraulic Fluid vs Hydraulic Oil
Typically, hydraulic fluid is a mineral-based liquid used to transmit power in hydraulic equipment. However, it doesn’t just transmit power; hydraulic fluid serves several functions, including heat transfer, sealing and lubrication, all constitutive to the smooth running of machinery.
The terms hydraulic fluid and hydraulic oil are occasionally used interchangeably, causing some confusion. While all hydraulic oils are hydraulic fluid, not all hydraulic fluids are hydraulic oil. Hydraulic fluids include a range of other mediums like water, water-oil emulsions and synthetic fluids, in addition to oil.
Hydraulic oil is a type of hydraulic fluid but they differ in several ways. The main differences are in viscosity, thermal stability and other physical attributes. Hydraulic oil usually contains a base oil and additives. Its viscosity needs to be high enough to maintain a lubricating film yet thin enough to flow at low temperatures.
Thermal stability is another attribute where it resists changes in viscosity even with temperature fluctuations. Synthetic hydraulic fluids, on the other hand, are designed to overcome limitations of mineral oils, exhibiting superior fire-resistance or ability to operate under extreme temperatures.
The addition of compounds to both fluid and oils helps combat specific problems such as wear, rust and foaming. Anti-wear additives serve to minimize wear in high-speed, high-pressure pumps; rust and oxidation inhibitors prevent rusting of components and the buildup of sludge; foam inhibitors suppress the formation of foam, which can cause erratic operation and loss of system efficiency.
Hydraulic Fluid vs Other Lubricants
Some common lubricants in construction equipment include transmission fluid for transmission systems, gear oil for gearboxes and engine oil for internal combustion engines. While these fluids share some similarities with hydraulic fluid, they have distinctive differences, making them fundamentally different.
Hydraulic fluid, for instance, is designed to provide power transmission throughout the hydraulic system. On the other hand, transmission fluids are specifically designed to lubricate, cool and clean transmission components and also enable gear shifts.
Similarly, gear oil is primarily designed for lubrication and protection of gearboxes, differentials and transfer boxes. Engine oil lubricates, cools and cleans an engine's internal components. It also helps seal the engine's parts.
While all these lubricants serve the common goal of reducing friction, what differentiates hydraulic fluid is its primary role is to transmit power as a medium of hydrodynamic pressure.
It is important to use the correct fluid type in heavy machinery since using an incorrect fluid can lead to breakdowns and malfunctions. Each fluid has a unique formulation suited to its application, making them non-interchangeable without the risk of machine damage or poor performance.
Maintenance Guidelines and Best Practices for Hydraulic Fluid
Ensuring hydraulic fluid is constantly topped off is a key aspect of hydraulic system maintenance. A system operating on inadequate hydraulic fluid can lead to erratic operation or cause serious damage to the hydraulic system.
Neglecting hydraulic fluid maintenance can lead to expensive repairs or total equipment failure. Pumps, cylinders and valves, some of the costliest components of a hydraulic system, can be damaged due to poor fluid condition, leading to downtime and increased repair costs.
An insufficient level of hydraulic fluid can often be identified by warning signs such as strange noises, frothing of the fluid, overheating, reduced power output or even the fluid appearing dark or having an off smell.
As a protective measure, hydraulic fluid should be topped off regularly, typically recommended every 1000 hours of use. However, the frequency could vary depending upon the system's utilization and environmental conditions, so it's vital to check the manufacturer's guidelines.
Finally, the storage and handling of hydraulic fluid is of particular importance. Hydraulic fluids must be stored in a clean, dry and cool environment away from heat sources or high humidity. Containers should be tightly sealed, and drums should be stored horizontally to prevent water settling on the drum bung.
Impact of Contaminants in Hydraulic Fluid
Hydraulic fluid contamination is one of the most detrimental maintenance issues for hydraulic systems. The most common contaminants include dirt, water and metal particles, but other substances can also compromise system performance.
Sources of contamination can be both internal and external. Internally, wear and tear of components are a fundamental source, producing metal shavings or rubber particles. Hydraulic hoses and seals may degrade over time, releasing minute particles into the fluid.
Externally, contaminants from the surrounding environment, like dirt and dust, can enter the system via the reservoir or cylinder rod seals.
Preventing hydraulic fluid contamination is vital. Regular fluid analyses and changing at the intervals recommended by the manufacturer are key steps toward maintaining a clean hydraulic system. The use of appropriate filtration systems can reduce the ingress of external contaminants, while periodic inspection and replacement of worn-out components can limit internal contamination.
Types of Construction Equipment Using Hydraulic Fluid
Key construction equipment that use hydraulic systems include, but are not limited to, excavators, bulldozers, loaders, cranes, backhoes and dump trucks.
An excavator, for instance, uses hydraulic fluid to drive the boom, arm and bucket movements, enabling the machine to dig, swing and carry dirt. Similarly, hydraulic systems in bulldozers power the movement of the blade for pushing materials and the ripper for breaking hard surfaces.
Loaders use hydraulics for the lifting and dumping of materials, while cranes employ hydraulics to elevate and lower heavy loads. In backhoes, hydraulics aid in the digging and lifting action of the extended arm.
Final Thoughts
In conclusion, the potential of hydraulic systems can only be fully realized with diligent maintenance and monitoring of hydraulic fluid. Regular checks on fluid levels, routine replacements in line with manufacturers' guidelines and preventive measures to curtail contamination ensure optimal equipment performance and longevity.
The EquipmentShare Shop offers a range of OEM and aftermarket parts tailored to heavy equipment hydraulic systems. Browse our growing catalog of heavy equipment parts to ensure your fleet stays in working condition. Don’t see exactly what your machines need? Reach out to our dedicated parts experts and get personalized assistance.
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