The Roles And Characteristics Of Hydraulic Fluid

August 11, 2022

The-Roles-And-Characteristics-Of-Hydraulic-Fluid It’s easy to ignore the significance of hydraulic fluid itself, no matter how familiar you are with hydraulic systems. To make sure that your system is capable of operating at maximum efficiency, there are a fairly large number of hydraulic fluid characteristics to take into account. Professional oil filtration experts suggest that as hydraulic systems are mechanical, they bear a lot of wear and tear throughout their journey, which leads to issues like ineffective filter oil and contamination. Effective and efficient hydraulic fluids play crucial roles in maintaining filtration systems. Also Read: Filtration Techniques For Hydraulic Systems In this blog post, we’ll examine the numerous characteristics of hydraulic fluid in your hydraulic filtration system, as well as the various aspects to take into account when selecting the best fluid for your requirements.

The Roles Of Hydraulic Fluid

First and foremost, hydraulic fluid is a means of transferring energy, enabling your gadgets to be powered by pistons, vanes, and other pumps. Because hydraulic fluid is non-compressible, unlike air, it is the best choice for applications that call for a quick response and more power than is often possible with pneumatic systems. While energy transfer is hydraulic fluid’s principal function, it also serves four additional secondary purposes, which are:

Heat Transfer

A hydraulic pump produces tremendous pressure inside of it when it is operating normally. Hydraulic fluid is forced into the gaps between system components by this pressure. Although this is a crucial aspect of how a hydraulic system functions, the friction caused by the fluid’s molecules rubbing against the equipment also generates a lot of heat.

Removing Contamination

Although a completely sealed hydraulic system would be ideal, no seal can indeed be perfect. That implies that your hydraulic fluid may occasionally be contaminated with very small amounts of water. Additionally, you may discover dirt or metal fragments in your fluid, which is often the outcome of wear over time. Filters, that capture and trap water and particles to stop them from harming your machinery, are used to eliminate these contaminants.


While O-rings and other seals do the majority of the work in sealing your hydraulic system, the ultimate seal is provided by hydraulic fluid, which fills the tiny gaps between these seals and other metal elements. This maintains pressure while preventing the entry of foreign substances into your system.


Hydraulic fluid has several crucial tasks, one of which is making sure that your gear is properly lubricated. The metal components of your equipment would rub against one another without this lubrication, quickly wearing down and delivering less power. This is why the foundation of hydraulic fluid frequently consists of mineral or synthetic oil. You may pick the appropriate degree of lubrication to keep your hydraulic system functioning well without placing additional strain on your system depending on the temperature of the job being done, the size of the machinery, the internal pressure, and other parameters.

Hydraulic Fluid Characteristics

With these different functionalities in mind, it’s time to examine the characteristics of hydraulic fluid that you should take into account when selecting the best fluid for your oil filtration system. There are several potential variations for each of these traits. But to choose the proper fluid, you must be aware of the specifications set forth for your equipment.


The viscosity of fluid indicates how difficult it is for it to flow; the higher the viscosity, the thicker or more difficult it will be to flow. Fluids become less viscous when they warm up due to the inverse relationship between viscosity and temperature. When selecting a hydraulic fluid, viscosity is crucial. Fluid must be sufficiently viscous to form seals and a lubricating coating over internal mechanical parts. But if it is too viscous, it will not flow at all.


Lubricity, which is connected to viscosity, describes how effectively a hydraulic fluid lubricates the machinery in your hydraulic equipment. Your fluid should leave a thin layer on everything within your hydraulic pump with the proper viscosity, even in the tiny gaps between closely packed parts.


While lubrication is responsible for lowering friction inside your equipment, another closely connected hydraulic fluid property you have to take into account is anti-wear. Zinc dithiophosphate (ZDP), one of the anti-wear additives, forms a coating on metal parts that reduces metal loss from close contact with other moving parts.

Corrosion Resistance

The majority of hydraulic fluids have chemicals that reduce the rate of corrosion in your system. These additives, which are referred to as R&O (rust and oxidation) inhibitors, prevent ferrous metals from rusting when they come into contact with the water that ultimately seeps into practically every hydraulic system.

Thermal Stability

Despite its significance, thermal stability is one of the most underappreciated properties of hydraulic fluids. While low-grade fluids will conduct heat, high-grade hydraulic fluids tend to withstand thermal degradation in high temperatures, making them perfect for high-pressure work.

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Harvard Filtration offers what it takes to meet your industrial filtration needs. We offer a broad range of filtration systems. Harvard filtration systems and filter carts are the most trusted and dependable portable filtration systems. Compatible with a broad assortment of petroleum-based and synthetic fluids, our filter carts can remove contaminants and water to a single micron, ensuring decreased hazardous waste disposal. Select our filters to experience your machine’s high performance. Contact us today here .

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