April 20, 2021

Hydraulic Fluid Contamination

Hydraulic Fluid Contamination

Today’s hydraulic equipment is designed to run at higher pressures and with finer tolerances than ever before. This makes it all the more important to monitor the purity of your hydraulic fluid. Hydraulic fluid contamination can impact your equipment’s performance, produce clogs, and damage vital components.

Controlling contamination can help you get the most out of your equipment by reducing wear-and-tear as well as the frequency of fluid replacement. And because hydraulic fluid disposal is regulated by federal and local standards, you can also expect to reduce the cost of hydraulic fluid disposal.

In this post, we provide an overview of hydraulic fluid contamination. What is it? Where does it come from? And what kinds of damage can it cause to hydraulic equipment?

What is Hydraulic Fluid Contamination?

hydraulic system leak

Hydraulic fluid is necessary to keep the moving parts of your equipment running smoothly. It lubricates components to eliminate friction and maintain the proper functioning of the machine.

Hydraulic fluid contamination refers to anything that prevents your hydraulic fluid from doing its job. This includes not only the introduction of contaminating particulates but anything that reduces the lubricating properties of your hydraulic fluid.

What some equipment owners may not realize is that hydraulic fluid contamination isn’t always visible to the naked eye. The human eye can see particles as small as 40 microns in diameter, but the particles that damage your machinery can be as small as 5 microns.

Newer machines run at higher pressures and with finer clearances, making them especially sensitive to hydraulic fluid contamination. Often, these machines will operate with a clearance of only 5-10 microns. That means your machinery can become damaged by contaminants that are completely invisible to the naked eye.

What Are Some Examples of Hydraulic Fluid Contamination?

Hydraulic fluid contamination can come in many forms, including ingressed particulate, built-in, generated, air, chemical, and water contamination.

Ingressed Particulate Contamination

An ingressed particulate is any solid matter that enters the hydraulic fluid from outside. This may include some of the following:

  • Dirt
  • Dust
  • Sand
  • Grit
  • Paint particles
  • Degraded seals
  • Metal particles
  • Cloth fibers
  • Rust

Don’t forget, these particles are often smaller than can be seen with the naked eye. Just because your hydraulic fluid looks clean doesn’t mean that you aren’t experiencing contamination.

Built-In Contamination

Even when your equipment is new, it’s possible to have contamination leftover from the manufacturing process. This can include contaminants like slivers of metal, tiny globs of excess grease, or sand left over from sand casting. New owners can avoid hydraulic fluid contamination by flushing their hydraulic system before use, as well as installing filters.

Generated contamination

Generated contamination happens through your equipment’s general wear-and-tear. As your equipment runs, the mechanical components can chip, and rubber seals can wear away. This often triggers a bit of a snowball effect: once contamination starts, it increases the wear on your equipment, which introduces more contaminants, which increases the wear even further.

This may sound frustrating, but it’s an unavoidable part of normal equipment operation. Owners can minimize damage by replacing their fluid regularly and by installing filters.

Air Contamination

fluid cleanliness

Even the atmosphere can be a source of hydraulic fluid contamination. At the purely mechanical level, air trapped in your hydraulic fluid can limit its compressibility. But at the chemical level, air exposure can oxidize the chemical components of your hydraulic fluid, significantly reducing its lubricating properties. If you notice that your fluid starts to have a white, foamy quality, you may be experiencing air contamination.

Owners should avoid allowing their hydraulic system to be exposed to air, and should keep their hydraulic fluid containers tightly sealed.

Chemical Contamination

Chemical contamination may occur simply from the natural breakdown of your hydraulic fluid. Excessive heat can accelerate this process, breaking your hydraulic fluid into individual chemical components that can cause harm to your equipment.

Chemicals introduced from outside the system can react with the hydraulic fluid. At best, this chemical contamination may reduce the lubricating properties of your hydraulic fluid. At worst, these chemicals may react with your hydraulic fluids and form indissoluble precipitates — solid particles that can cause clogs and other physical damage to your system.

The primary source of chemical contamination is the mixing of two different hydraulic fluids in the same machine. The additives in each fluid may not be compatible, resulting in the kinds of damage described above. Owners should be sure to use only one type of fluid per machine. Check with the manufacturer to ensure you’re using the hydraulic fluid that’s right for your equipment.

Water Contamination

We all know that oil and water don’t mix, and when water droplets enter your system it can reduce the lubricating properties of your hydraulic fluid, as well as limit its compressibility. Owners can prevent their fluid from absorbing moisture by keeping their containers sealed.

The Damage and Hazards of Hydraulic Fluid Contamination

The type of damage caused by hydraulic fluid contamination varies by the type of contamination you’re dealing with. Generally, fluid contamination results in the mechanical components of your equipment becoming jammed. And as mentioned earlier, this can often introduce a “snowball” effect, where jammed equipment introduces new contaminants, and can worsen quickly.

When water or particulates get into your hydraulic system, they can form insoluble sludges and solid precipitates, which can cause clogs on system components such as pumps, nozzles, and jets.

Solid particles can become a grinding paste inside your equipment, causing further erosion and wear to sensitive parts and surfaces. Newer equipment can be especially sensitive to small particulates, but even older machines can sometimes have an oil thickness of only 5-10 microns. Contaminants larger than this will disrupt the lubricating properties of the oil, resulting in additional damage.

Any form of hydraulic fluid contamination can result in decreased performance as well as increase the possibility of future, costly repairs. In some cases, contamination can lead to catastrophic failure. While your machinery will always experience some degree of wear-and-tear, controlling hydraulic fluid contamination will keep your contamination problems from spiraling out of control, and improve the overall lifespan of your equipment.

How Does Hydraulic Fluid Contamination Occur?

It’s helpful to think of two broad types of hydraulic fluid contamination: (1) internal contamination and (2) external contamination.

Internal Contamination

hydraulic fluid sampling and analysis

Internal contamination occurs from the general operation of your equipment. Moving parts will always have some degree of friction, and rubber seals can wear away, leaving particulate matter behind.

This is unavoidable, though manageable through preventative maintenance and the use of filters. Additionally, internal contamination may be the result of the manufacturing and/or service process, so operators should always flush the hydraulic fluid of machines that have been recently purchased or serviced.

External Contamination

External contamination refers to any contamination that enters the system from the outside. Above, we covered things like air, water, and outside chemicals. Knowing how these elements get in can be key to keeping them out.

Unsealed hydraulic fluid containers can allow water, chemicals, or debris to enter from the surrounding environment. Always keep your containers sealed and stored in a location protected from extreme temperatures.

Dirty hydraulic fluid containers can introduce contaminants when they are refilled. Periodically flushing these containers can prevent these microscopic particulates from contaminating a fresh supply of hydraulic fluid.

Cheap hydraulic fluid may not have the purity rating your hydraulic equipment demands. Even if it looks clean, it may contain particulates that will cause damage to your sensitive equipment. Always check with your manufacturer to determine the quality hydraulic fluid you need for maintaining proper operation.

Mixing two different types/brands of hydraulic fluid can spell disaster, especially if their chemical additives are not compatible. Only use the hydraulic fluid recommended by your equipment’s manufacturer.

Damaged seals can allow contaminants to enter the system. If you spot a leak, you may be looking at a hydraulic fluid contamination problem. After all, if water or other fluids can get out, there’s a good chance that undesirable elements are getting in.

Always learn the tolerances of your hydraulic equipment. Older equipment is less sensitive to contamination because these machines run at lower pressure and have greater clearances. It may be tempting to expect your newer equipment to have the same sensitivity standards. Don’t. Your newer equipment operates at greater pressures and finer clearances than their older counterparts. The result is superior performance, but it comes with the demand for cleaner hydraulic fluid. Take care of your equipment, and you can expect it to last longer and perform better in the long run.

How MAC Makes the Difference

At MAC Hydraulics, we understand your concern for the overall purity and reliability of your hydraulic fluid. Controlling hydraulic fluid contamination is critical for the operation and lifespan of your equipment. Contamination also increases the frequency at which your hydraulic fluid needs to be changed, and the cost of disposing of the old fluid can be costly as well.

If your hydraulic system requires maintenance, contact us today. We can provide the expertise and care that you need to keep your equipment running and provide you with the skills you need to keep your hydraulic system clean, pure, and worry-free.

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