How Air Sentry Breathers Work

Air Sentry® Breathers replace existing breather caps or air vents on fluid holding storage tanks, hydraulics reservoirs and gearboxes. Most older style air venting methods provide minimal if any contamination control. Air Sentry® Breathers provide the first line of defense in contamination control methodology utilizing patented designs and featuring color indicating silica gel and self cleaning 2-micron filtration. ⬇️ Download a comprehensive spec sheet here.

Diagram 1: Clean Dry Air

Air enters the breather through a 360-degree opening in the top cap, which is designed to withstand rain and wash-down.

• Stage 1: A self-cleaning filter removes particles larger than 2 microns, protecting equipment from wear.
• Stage 2: Silica gel adsorbs up to 95% of moisture from the incoming air. The silica gel changes color from gold to dark green as it absorbs moisture.
• Stage 3: A second 2-micron filter captures any remaining particles before the air reaches the equipment.

This three-stage filtration process ensures that the equipment receives clean, dry air. The color change of the silica gel visually indicates when the breather needs to be replaced.

Diagram 2: Exhaust Air

When air is expelled from the equipment back through the breather, water vapor is adsorbed by the silica gel. If the silica gel turns green from the bottom, it indicates excessive moisture inside the reservoir.

Most Air Sentry® models include a layer of carbon-impregnated foam in the bottom. This foam absorbs small amounts of oil vapor, protecting the silica gel from contamination. Adapters are available for applications with excessive oil mist.

As the air exits the breather, it passes back through the self-cleaning 2-micron filter. This "backflushes" the filter, removing any particles trapped during air intake.

Desiccant Breather Selection Guide

Want to make sure you are selecting the right breather for you? Check out our guide:

Guardian Series | The Gold standard for Contamination Control 🏆

The only series made for usage with Diesel Fuel. Ideal for most applications. Features check valves, Tritan construction, replaceable cartridges, stackable cartridges, optional gauge, and optional isolation check valve. Shop now >

L-Series | For In-Line Low Airflow Applications 💨

For use with air exhaust lines, vacuum lines, low pressure compressed air lines, marine vehicles and other in-line airflow applications where clean, dry air is required. Shop now >

M-Series | For Heavy Duty Applications 💥

For use with heavy duty off-road equipment, heavy mobile equipment, high temperatures, and corrosive chemicals. M-Series breathers are capable of handling the requirements of the most severe environments. Shop now >

R-Series | For High Vibration Applications 🚜

For use with high vibration, mobile applications like cranes, railroads, farm or construction vehicles, and off-road trucks. R-Series breathers are easily mounted via rugged steel pipe threads and a reusable metal base. Shop now >

X-Series | For High Humidity, High Dust Applications 💦

For use in high humidity, high dust environments such as paper mills, wash down areas, steam cleaning rooms, mine quarries. The check valves provide a closed system until airflow is required, extending the life of the desiccant. Shop now >

XR-Series | For Extreme Environments ⚠️

For use with windmills, mining equipment, mobile equipment, or in any extreme environment where protection from dust, moisture and vibration are critical. The base is designed to handle the rigors of high vibration applications. Shop now >

Z-Series | For Limited Space Applications 🛢️

For limited space applications, storage tanks, drums, totes, small oil containers, and Oilsafe Storage Systems, where space is limited or air flow requirements are below 5 cfm.The Z-series is typically used on gearboxes and low fluid volume applications where mounting space is limited. Shop now >

D-Series | For Stationary Applications (Disposable) 🔄

For stationary applications such as storage tanks, fluid reservoirs, transformers, pumps and gearboxes. D-Series breathers feature numerous models in a variety of sizes, designed to satisfy the requirements of most stationary fluid management applications. Shop now >

Breather Adapters | Connectors for Tanks, Reservoirs and more ⚙️

These act as connectors for storage tanks, gearboxes, hydraulic reservoirs and more. We offer various types of adapters including splash, bayonet, domed flange, gearbox, and hydraulic reservoir. Shop now >