Can You Remove Water from Hydraulic Fluid?

Hydraulic fluid is a vital component in many industrial and mechanical systems. However, it can become contaminated with water, which can lead to efficiency losses and potential system failures. Removing water from hydraulic fluid is a common practice in various industries, including marine operations and aviation maintenance. This article will explore how to effectively remove water from hydraulic fluid and the methods used in the process.

Understanding the Problem

When we talk about removing water from hydraulic fluid, we often refer to two scenarios: the chemical transformation of hydraulic fluid into water and the removal of entrapped water in the fluid. While the first scenario is not practical, the second is a standard practice that is carried out frequently.

Methods of Removing Water from Hydraulic Fluid

The most common methods for removing water from hydraulic fluid are industrial dehydration processes, decanting, and using specialized equipment such as centrifuges and vacuum evaporators.

Industrial Dehydration

For large-scale industrial dehydration, low-vacuum dehydration units are often used. These units are highly effective and can provide a quick return on investment (ROI). However, if quick results are not necessary, the water-hydraulic fluid mixture can be sold as scrap.

An alternative option is the use of cellulose media for moisture removal, which is suitable for smaller percentage removal of mixed oil.

Decanting

A practical and basic method for removing settled water and oil is through decanting. This involves leaving the hydraulic fluid to settle and then manually transferring the clearer hydraulic fluid to a new container while the settled water remains in the original container.

Centrifugation

A more efficient method is the use of a centrifuge. A centrifuge will apply a high force to the mixture, which separates the water and oil due to their density differences. The water, being denser, will be pushed towards the outside of the centrifuge, while the oil remains in the center. This process can significantly improve the separation of water from hydraulic fluid.

Vacuum Evaporator

In situations where the water content is diffuse, a vacuum evaporator is a suitable solution. By applying a vacuum, the water is evaporated while the oil is retained. This method is particularly useful when the oil contains a small percentage of water.

Another Approach

For a simpler approach, you can set up an apparatus similar to a bucket. Pour the hydraulic fluid and water mixture into the bucket and wait for the water to settle at the bottom. Since water is more dense than oil, you can scoop the hydraulic fluid off the top or have a spigot to drain the water from the bottom. This method, though less precise, can be effective for smaller volumes.

Additional Techniques

To enhance the water removal process, you can heat the mixture and ventilate the headspace of the reservoir with very dry air. Bubbling dry air below the free surface in the tank can also help in better mixing. Ensure that the entire system is well grounded to prevent electrical hazards and spark generation.

Conclusion

Removing water from hydraulic fluid is an essential maintenance practice to ensure the optimal performance of hydraulic systems. Whether through industrial dehydration, decanting, centrifugation, or vacuum evaporation, there are several methods available to achieve this goal. Understanding the appropriate method for your specific situation will help maintain the efficiency and longevity of your hydraulic systems.

Keywords: hydraulic fluid, water removal, dehydration, centrifuge, vacuum evaporator