17 Nov 2023

The vital role of return line filters in hydraulic systems

In the complex world of hydraulic systems, where precision and reliability are increasingly important, every component plays a vital role in ensuring smooth operation and longevity.
Among the often-underestimated circuit components is the return line filter, a seemingly unassuming element that is, in fact, the guardian of hydraulic system efficiency.
In this month’s post, we will delve into the significance of return line filters in hydraulic circuits and explain why they deserve an important place in every hydraulic setup.

What is a Return Line Filter?

Before we dive into the importance of return line filters, let’s understand what they are.

This filtration device is installed in the return line of a hydraulic circuit.
The primary function of the return line filter is to capture and remove contaminants from the hydraulic fluid before it returns to the tank.
This seemingly simple role has a significant influence on the overall performance and longevity of the hydraulic system:

  1. Prolonging Component Life

Imagine the hydraulic system as a finely tuned orchestra, in which every component must perform harmoniously. Contaminants, such as dirt, debris and particles, act as discordant notes that can disrupt this harmony.
Without a return line filter, these contaminants can circulate freely within the hydraulic fluid, leading to the premature wear and tear of critical components like pumps, valves and actuators.
By removing contaminants, return line filters extend the lifespan of these expensive components, saving both time and money in the long run.

  1. Ensuring Smooth Operation

Smooth and reliable operation is the hallmark of an efficient hydraulic system. Contaminants in the fluid can lead to poor performance and even system failure.
Return line filters help maintain the fluid’s cleanliness, ensuring that hydraulic components function optimally.
This translates to enhanced productivity, reduced downtime and improved overall system performance.

  1. Preventing Costly Repairs

Hydraulic system repairs can be both time-consuming and costly. Contaminant-induced failure can result in extensive damage that requires system flushing and cleaning as well as component replacement.
Return line filters act as a cost-effective insurance policy, preventing the need for expensive repairs and the associated downtime.

  1. Maintaining Fluid Quality

Hydraulic fluid quality is essential for system efficiency. Contaminated fluid can lead to increased heat generation, reduced lubrication and decreased overall efficiency.
Return line filters continuously remove contaminants, helping to maintain the fluid’s integrity and ensuring that it performs optimally, even in demanding applications.

  1. Customizable Filtration

Last but not least, one of the main advantages of return line filters is their adaptability to different filtration needs.
They come in various configurations, from basic spin-on filters to premium in-tank units with high-filtration-rating fiberglass elements.
This allows hydraulic system operators to choose the level of filtration that best suits their specific requirements, whether in the context of heavy industry or a precision application.

How to Size a Return Line Filter

Return line filters must be sized considering the maximum flow rate of the return line over the entire machine cycle; in particular, in the case of differential cylinders, the return flow rate could be greater than the pump flow rate.
Return line filters can be installed either in line or on the top of the hydraulic tank and must be selected taking into account the operating pressure of this part of the system.

These filters are often provided with a bypass valve to prevent dangerous excessive back pressure in the return line resulting from the clogging of the filter element.
The filter outlet must always be located below the fluid level, under all operating conditions, to avoid foaming in the tank.

Moreover, in the case of in-tank assemblies, the return fluid is channelled directly down the tube into the reservoir, eliminating any potential fluid disturbance.

For a complete overview of UFI Filters Hydraulics’ return line filters range, please click here.

To select the best filtration solution for the return line of your hydraulic system, please try our CAF Computer Aided Filter Selector, available in the Webtool section of our website, or contact our Sales team for any specific support or requirements.