To start at the beginning: according to the Cambridge Library desiccant means: "a substance used to remove moisture from something". Thus: a desiccant breather removes humidity out of the air as it is passing through a filter. The goal is to dry the air before it enters your precious reservoir.
What about a vent cap?
A vent cap is simpler, easier to place and a cheaper solution, but.......
Equiment OEMs include breather caps on the fill port to allow expanded air to escape. However, there is one problem: while the vent caps let air out, they don't prevent small, dirty particles and moisture from entering the equipment. And there the problems start:
What If a desiccant breather would not exist?
Then following problems would arise:
..... and your fluid would look like this: ↓
condensation - rust - oxidation - particulates - sludge - corrosion ..............
The wide range of Air Sentry desiccant breathers are designed to replace the breather cap on:
The breathers adsorb water from the air before it enters your fluid system AND remove particulate contaminants as small as 2 microns.
The image on the right indicates how the desiccant breather allows outside air to enter through the 360° opening in the breather’s top cap. The top cap design overhangs the body of the breather helping protect the breather from rain, sleet, snow, as well as most equipment wash-down procedures.
This three stage filtration design ensures your equipment gets CLEAN, DRY AIR!
As the color indicating silica gel adsorbs moisture it changes from gold to dark green. When the silica gel is adsorbed to its capacity (approximately 40% of its original weight), the breather has fully turned dark green. This color change is easily seen and serves as the visual indication that it is time to remove and replace the disposable breather.
The diagram below indicates air being expelled back through the desiccant breather from the equipment the breather is mounted on.
As contaminated air travels this reverse path, expelled water vapors are adsorbed by the silica gel. During this reverse air flow process, the silica gel indicates the presence of excessive moisture inside the reservoir as the gold silica gel turns to dark green from the bottom of the breather rather than from the top of the breather.
An additional feature located in the bottom of most Air Sentry® models is a layer of carbon impregnated foam. This carbon pad absorbs small amounts of oil vapor exhaled from the tank and protects the silica gel from minor oil mist contamination.
Excessive oil mist control may be required. Adapters are available for applications with excessive oil mist problems.
As the exhausted air passes back through the self cleaning 2-micron filter, located in the top cap of the breather; any particles that were trapped as air entered the system are now back flushed from the filter.
Air Sentry Products - the gold standard in contamination control
Air Sentry products are powerful preventive maintenance tools and cover a wide range of application requirements. The line consists of Good, Better and Best options designed to meet your specific application and duration specifications.
Air Sentry D-series desiccant breathers
The models in this group satisfy most applications involving hydraulic reservoirs, lubrication and fuel storage tanks, transformers, pumps and gearboxes.
Models D-100, D-101 and D 102 are rated for airflow of 35 cfm.
Model D-108 is rated for 100 cfm.
Type of medium: 100% sillica gel.
Max. air flow/fluid flow: 20 cfm / 150 gpm.
Air Sentry Z-series desiccant breathers
These are the “Mini Breathers”.
They are designed for applications where space is limited or airflow is minimal (10 cfm or less).
They are often used for gearboxes, drums, totes and small reservoirs.
Type of medium: 100% silica gel.
Max. air flow/fluid flow: 5 cfm / 37 gpm.
Air Sentry X-series desiccant breathers
The X-Series Breather line was designed for extreme humidity. Ideal environments include paper mills, or anywhere that humid air is a problem.. The X-Series models incorporate check valves that allow air to enter through the breather only when required, thereby extending the life of the desiccant and the useful life of the breather.
Type of medium: 100% sillica gel.
Max. air flow/fluid flow: 20 cfm / 150 gpm; except X-100 is: 10 cfm/75 gpm.
Air Sentry Guardian-series desiccant breathers
The GUARDIAN takes check valve technology and cost-saving replacement measures to the next level. Air Sentry also introduces four exclusive advancements that will again raise the bar in contamination control:
This patented material is the most chemical, temperature, and impact-resistant breather on the market.
Isolation Check Valve
The isolation check valve isolates the desiccant from exhaust air to lengthen service life of the desiccant while also protecting it from volatile and splashing fluids.
Integrated Compound Vacuum / Pressure Gauge
This proprietary feature is a true-life accurate indicator of filter conditions.
Stack cartridges to extend the life of breathers even further using the Modular Stack Ring™.
For more information download the brochure:
Determine CFM requirement:
Choose the Right Series:
Determine Connection Size:
Evaluate Mounting Area:
Aluminum Extrusion, Forging & Rolling Mills
Pulp & Paper
Steel Mills & Foundries
Chemical & Petrochemical
Desiccant breathers are preventive maintenance tools.
They protect your equipment.
But contamination control cannot be reached by desiccant breathers only. You will also need:
By using these solutions together, life of machine and lubricant can be maximized and capital and operating expenses be minimized.
Enluse offers a full line of desiccant breathers.
Almost forgot the best part: ROI →
Let us help you finding the right breather for your application. The first step to extend a system's life.
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