04 Feb

In our latest blog we take a look at desiccant breathers and explain why they are used and how they work to maximise the efficiency of a hydraulic units breathing system.


The desiccant breathers main role is to protect a power units breathing system and filter out moisture and contaminants drawn in from the working environment, thus helping to prolong the life and efficiency of the power unit.

How does it work? 
– The desiccant breather unit contains silicone based gel which helps prevent particulate entering the system during operation. They also work to soak up any moisture that is in the system while it is in shut down or during a service period.

In environments where there are high ambient levels of humidity, such as offshore oil rigs, optional breathers with check valves are available which come in the necessary fitments for most power units.

Where is it fitted?
  – The desiccant breather replaces the unit’s standard OEM breather cap, coming in a screw-on fitment and in a number of different sizes depending on your type of hydraulic system.

How do I make sure I choose the right filter?   Many leading suppliers of desiccant breathers have product configurators on their site so you can choose from a number of crucial variables that are tailored to your system:


Airflow - which typically varies from 0-27CFM, giving a good pointer as to the amount of air that typically passes through the breather system during operation


Unit dimensions – Including height and diameter measurements to ensure the breather fits the unit without coming into contact with other parts or compromising unit space


Amount of silica gel needed – This is largely dependent on the size of the system and working environment as to how much silica gel is needed to stop particulate contamination and excess moisture accumulation


Absorption capacity – typically measured in fluid ounces, this capacity can change due to the nature of the application and the environment it is situated in


Operating temp – The filters are built to withstand large temperature fluctuations, so it is common to see operating temperatures range from around -40°C to 149°C which covers a wide range of operational and environmental conditions


Filter efficiency – An average sized desiccate breather is able to achieve in the region of 0.3µ absolute (β₀.₃≥200) efficiency under normal operating conditions.


Build quality – As technology is constantly evolving, filters are being built to withstand obstacles such as unit vibration and impact protection, and constant development is enabling filters to withstand harsher environments and temperature changes (as detailed above) with stringent product testing taking place.


With bespoke hydraulic units that use these breathers on applications such as offshore oil rigs, where humidity and other factors can potentially hamper a unit’s performance, it is imperative that the breather unit can tackle these obstacles in an effective manner.


Connections – Desiccant breather filters typically use a UN female thread to connect to a power unit with various sizes of this connection being available dependent on application.