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The Basics of Hydraulic Fluids

The Basics of Hydraulic Fluids

Hydraulic systems are widely used in various industries for their ability to transmit power efficiently. Hydraulic fluids are the lifeblood of hydraulic systems, playing a crucial role in the operation of a wide range of machinery. From construction equipment to industrial manufacturing, hydraulic fluids work under pressure to transmit power, lubricate, seal, and transfer heat. In this blog post, we’ll explore the basics of hydraulic fluid, the different types available, and their varied applications.

What is Hydraulic Fluid?

Hydraulic fluid, also known as hydraulic oil, is a non-compressible liquid that is the medium by which power is transferred in hydraulic machinery. The basic idea behind any hydraulic system is very simple: Force that is applied at one point is transmitted to another point using an incompressible fluid. This allows for highly efficient, reliable, and constant applications of force.

Hydraulic fluid plays a vital role in lubricating moving parts, preventing corrosion, and dissipating heat within the system. Hydraulic fluids are designed to withstand high pressures and temperatures while maintaining their properties.

Hydraulic fluid serves several important functions in hydraulic systems:

Power Transmission: It transfers power from one part of the system to another. This is the primary role of hydraulic fluid, and it is accomplished by the fluid flowing under pressure through the system.

Lubrication: It lubricates the components of the hydraulic system, reducing friction and wear, and helping to extend the life of the system.

Heat Transfer: Hydraulic fluid helps to remove heat from the system components. As the fluid circulates, it carries heat away, which is then dissipated in the cooler parts of the system or via a heat exchanger.

Sealing: It provides a seal in various parts of the hydraulic machinery, improving efficiency and preventing leaks by maintaining a tight fit between components.

Contaminant Removal: The fluid carries away contaminants and debris from critical areas of the system, which are then filtered out.

Types of Hydraulic Fluids

There are several types of hydraulic fluids available, each with its own unique characteristics and applications. Different types of hydraulic fluids have varying characteristics that affect their performance and allow them to meet the specific requirements of each application. Some of these variable qualities include:

  • Viscosity/Grade
  • Temperature resistance
  • Anti-wear characteristics
  • Biodegradability
  • Corrosion prevention
  • Fire resistance
  • Cost

And more.

Most hydraulic systems are able to operate using many different types of fluids, so it is recommended to adhere to OEM specifications for best results. Some common types of hydraulic fluids:

Mineral Oil-Based

Mineral oil-based hydraulic fluids are the most common type used in hydraulic systems. They offer good lubrication properties and are cost-effective. However, they are not suitable for high-temperature applications.

Water-Based

Water-based hydraulic fluids consist of a water and glycol mixture and are more expensive than mineral-oil based oils, but cheaper than synthetic. As these fluids contain a high percentage of water, they are ideal for applications with a high-risk of fire, but do not offer the same wear protection as oil-based or synthetic hydraulic fluids. 

Synthetic

Synthetic hydraulic fluids are formulated using synthetic base oils and additives. They offer better performance at extreme temperatures and provide enhanced protection against wear and corrosion. Synthetic fluids are ideal for high-performance hydraulic systems but will come at an increased cost.

Biodegradable

Biodegradable hydraulic fluids are environmentally friendly options that are biodegradable and non-toxic. They are commonly used in applications where spills could harm the environment, such as in agriculture or marine operations.

Applications of Hydraulic Fluids

Hydraulic fluids are used in pumps, motors, (read about the difference here) cylinders, and more in order to accomplish tasks in a variety of industries. The wide range of applications for hydraulic systems include:

Construction: Excavators, bulldozers, and loaders rely on hydraulic systems (particularly hydraulic cylinders) for their digging, lifting, and pushing.

Trucking: Many trucks such as dump trucks, wreckers, haulers, and more trucks utilize hydraulic systems in the form of gear pumps, wet line kits and power take-off (PTO) systems.

Forklift & Lift Equipment: Forklifts utilize hydraulics to raise and lower their forks while aerial work platforms and telehandlers can extend their platforms and booms using hydraulic systems.

Automotive: Hydraulic fluids are used in automotive applications for power steering systems, brake systems, and suspension systems.

Industrial Machinery: Factory machines including hydraulic presses and conveyor systems utilize hydraulic fluids to control their movement. 

Agricultural Equipment: Farm equipment such as tractors and harvesters use hydraulic systems to operate attachments such as plows and combines. 

Understanding the basics of hydraulic fluids and choosing the right type for your application is essential for the efficient operation of hydraulic systems. A well-maintained hydraulic system can result in great increases in productivity, and it all starts with the fluid inside.

Hydraulic Parts at Iron Wing

Looking for replacement parts for your hydraulic system? We've got you covered! We carry a large range of parts for heavy-duty truckheavy equipment, industrial, forklift & lift equipment, and more. Our hydraulic inventory includes pumpsmotors, cylinders, hoses, filters, and more! Search our store by part #, description, or manufacturer and easily filter your results!