Why Hydraulic Fluids Are Essential in Modern Machinery

Hydraulic systems like pumps and motors can be found in many different machines. The main components of hydraulic systems are the reservoir, pump, valves and actuator. But there is another critical component not mentioned above: the hydraulic fluid itself.

What is the role of hydraulic fluids within these systems?

The main role of hydraulic fluid is to serve as a medium for transmitting power in hydraulic systems. Hydraulic fluid also performs several other important functions, like regulating heat, preventing contamination, lubrication, and sealing the hydraulic system.

Hydraulic systems are vital to everyday life, performing important roles in cars, aircraft, industrial machines and construction equipment. In order to understand hydraulic fluid, it’s valuable to learn its role within the hydraulic system and the many duties it performs.

Transmit Energy

Hydraulic fluid’s most important role is to transfer power. Hydraulic fluid is a medium for transferring power because it is incompressible. Therefore, in a confined vessel like a pump system, when force is applied at one point to the fluid, it quickly moves and transmits that force to another point.

This transition of mechanical movement to flow power, and back to mechanical motion, is what allows hydraulic systems like pistons and rotary motors to function. Because fluid is such a strong and incompressible medium, it means hydraulic systems can perform heavy-duty tasks like elevating cars or extending a plane’s landing gear. In addition to its main role as a power transfer method, hydraulic fluid has several key secondary functions.

Regulate Heat

One important duty of hydraulic fluid is to regulate the temperature of the system. Hydraulic fluid can be cooled within the reservoir before it is pumped. As it passes through and around the moving parts of the system, the fluid cools them and carries heat back to the reservoir where it can dissipate.

Hydraulic fluid provides the opposite effect for machines operating in very cold conditions. Certain hydraulic fluids can be heated before being pumped through the system, keeping the parts warm and allowing the system to continue working even in colder environments.

Prevent Contamination

Hydraulic fluid also removes contamination from the hydraulic system. Although seals and filters block most contaminants, no system or seal is perfect. Contaminants include dirt and water from outside, and small particles of metal and chemicals that break off of hydraulic components during use.

Over time, particles will enter the fluid and create extra friction and wear on the moving parts, which damages operation and efficiency. When hydraulic fluid is pumped through the system it attaches to these particles of grime and metal and flushes them out as it circulates.

Lubrication

One important function of hydraulic fluid is lubrication. Hydraulic systems are comprised of many metal parts moving against one another and without constant lubrication, these parts would quickly begin to wear down. Hydraulic fluid is a mixture that contains lubricants like vegetable and mineral oil or synthetic lubricants. As it is pumped through the system, hydraulic fluid lubricates areas that are in constant motion like piston, vane, or gear pumps and valves which are constantly opening and closing.

Sealing

Another role of hydraulic fluid is sealing hydraulic systems. Hydraulic systems need to maintain pressure in order to function; although systems use gaskets, valves and other measures to stop leaks and maintain pressure, hydraulic fluid provides an additional seal.

By being forced through the system at pressure, the fluid works its way into the cracks between components and around seals, and provides an internal seal between parts. Small particles that may enter the machine by passing through the gaps are repelled by the miniscule barrier formed by surface tension in hydraulic fluid.

Summary

Hydraulic fluid performs critical roles within hydraulic systems from transmitting power to lubricating parts and regulating temperature. The main factors to consider when thinking about the best hydraulic fluid for a given system are viscosity, heat resistance and anti-wear. Another valuable aspect to consider is visibility. Dyed fluids are more visible and may help operators to spot a leak in the system early.

In Need of Hydraulic Repair Services?

Servo Kinetics in Ann Arbor offers the industrial hydraulic repair services your equipment needs. If you have questions about the performance of your hydraulic motor, pump or rebuild we can help. Speak with one of our engineers for some troubleshooting tips or visit us for a reliability centered maintenance check. Our hydraulic repair services are dependable and trusted due to our extensive experience and commitment to customer care.