5 Things to Consider When Selecting a Desiccant Breather

Desiccant breathers play a crucial role in maintaining the efficiency of machines by preventing contamination and moisture from entering the circulating oil. However, not all desiccant breathers are created equal, and selecting the right one involves careful consideration of several key factors. In this guide, we’ll explore the essential criteria for desiccant breather selection to ensure optimal performance in everything from gearboxes to off-road construction equipment.  


The first factor to consider is the operating environment. The level of contamination in the surroundings significantly influences the choice of desiccant breather. Environments with water spray, excessive dirt, or other severe conditions necessitate the use of breathers designed to withstand higher amounts of ambient contamination. In these cases, breathers with check valves and washdown caps can be particularly beneficial as they add an extra layer of protection, preventing the intrusion of contaminants and extending the breather's operational life.


The type of equipment and the nature of the work being performed are critical considerations when selecting a desiccant breather. Different applications require different breather models. Here are some common application categories:

Disposable stationary applications: Suitable for gearboxes, fluid reservoirs, transformers, pumps, and storage tanks.

Limited space applications: Designed for gearboxes, drums, totes, and small oil containers where space is a constraint.

High humidity/dust applications: Ideal for environments such as paper mills, wash-down areas, steam cleaning rooms, cement plants, steel making plants and mine quarries.

High vibration applications: Tailored for equipment like cranes, railroad maintenance vehicles, shaker screens, construction vehicles, and off-road trucks subjected to vibration and mechanized shock.

Extreme environment applications: Customized for exposed equipment like windmills, wind power turbines, mining equipment, on/offshore platforms, etc.

Understanding the specific application requirements ensures that the selected breather is best suited to the intended purpose.

Airflow Rate

Airflow rate is a critical parameter in desiccant breather selection. The breather's size is determined by the required cubic feet per minute (CFM) of airflow. It is essential to choose a breather with a higher CFM capacity than the actual requirements of the tank or reservoir. Insufficient airflow can lead to excessive pressure or cause a vacuum that may damage the equipment.

Additionally, it is equally crucial to ensure the breather does not impede the flow of lubricants within the system. Inadequate CFM capacity can restrict airflow to the point where it interferes with lubricant flow, potentially leading to friction, overheating, and accelerated wear and tear.

Reservoir Capacity

The reservoir capacity directly impacts how quickly the desiccant may become saturated with moisture, especially in systems with larger amounts of oil, which could mean higher humidity, but would certainly mean that the breather has to work more exhaustively than a smaller reservoir. Additionally, the size of the reservoir affects headspace fluctuation, influencing the volume of air passing through the breather.

Each desiccant breather model has specific reservoir capacity requirements, and it is imperative to check the breather model number for precise information on the relationship between desiccant capacity and reservoir size before making a purchase.

Flow Characteristics

Desiccant breathers are rated for either continuous or intermittent flow. This distinction becomes crucial in determining whether the breather incorporates check valves to enhance its lifespan. Continuous flow applications may benefit from breathers with check valves to prevent backflow and maintain optimal performance over an extended period.

Benefits of Continuous Flow

Consistent Protection: Continuous flow breathers ensure a constant exchange of air, maintaining a protective barrier against contaminants throughout the machinery's operational life.

Preventing Backflow: In applications where the risk of backflow is heightened, continuous flow breathers often incorporate check valves. These valves act as one-way gates, preventing contaminants from re-entering the system during rest periods.

Benefits of Intermittent Flow

Conserving Desiccant Life: In intermittent applications, desiccant breathers often incorporate features to minimize desiccant exposure during inactive periods, conserving desiccant life and optimizing its moisture-absorbing capacity when needed.

Energy Efficiency: By adapting to the machinery's operational rhythm, intermittent flow breathers contribute to energy efficiency. They activate precisely when required, preventing unnecessary air exchange during dormant phases.

Adaptable Performance: Intermittent flow breathers are engineered to handle the dynamic nature of start-stop cycles, ensuring reliable protection while accommodating the intermittent demands of the machinery.

Bottom Line

Selecting the right desiccant breather involves a thorough evaluation of the operating environment, application requirements, airflow rate, reservoir capacity, and flow characteristics. By considering these factors meticulously, one can ensure the longevity and effectiveness of the chosen desiccant breather, contributing to the overall reliability of the machinery and systems it protects. Take the guesswork out of breather selection, check out OilSafe’s breather selection tool.

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