Why it matters that your equipment receives clean, dry air and how desiccant breathers make it happen.

Why Are Desiccant Breathers Needed?

An estimated 70% of machinery “loss of use” is due to surface degradation, with 50% attributed to mechanical wear and 20% attributed to corrosion. The most common causes of corrosion and mechanical wear are moisture and dirt originating from outside the machine.

When a fluid reservoir warms up and then cools down, or when hydraulic cylinders extend and retract, the system “breathes” air in from the outside.

• If this air is humid, moisture enters the system and condenses inside the reservoir as it cools.
• If this air contains dust and other particulates, the particles settle into the fluid and contribute to wear.

A typical fill cap or reservoir vent provides minimal or no contamination control. These components have no mechanism to prevent harmful moisture and particulates from entering the system.

In short, desiccant breathers help ensure that equipment receives the dry, clean air needed to minimize mechanical wear and corrosion.

What Is a Desiccant?

A desiccant, such as silica gel, is a hygroscopic substance, meaning it attracts and holds water molecules. Small desiccant packs are commonly found in shoe boxes, food packaging, vitamin bottles, and other products where moisture prevention is important.

What Is a Desiccant Breather?

A desiccant breather contains desiccant infused with a chemical that changes color as moisture is absorbed. This color change allows the saturation level to be visually monitored.

Applications

Desiccant breathers are not industry-specific. They should be considered for any system containing expensive, moisture-sensitive lubricants or operating in a humid or dusty environment.

• Lubricant storage tanks, totes, and drums
• Gearboxes, hydraulic systems, and circulating systems
• Transformers
• Applications that require dielectric strength to be preserved
• Fuel tanks

Best Practices

• Select the proper breather: One size does not fit all.
• Use visual monitoring: Desiccant breathers typically change color to indicate when replacement is needed.
• Use intake check valves: These valves allow airflow only when there is a pressure difference between the fluid reservoir and the atmosphere, helping extend the life of the desiccant.
• Use a vacuum gauge: A color change indicates the condition of the desiccant, but the breather may also need to be changed if the particle filter becomes plugged. A manual-indicator vacuum gauge is an effective way to identify this condition.
• Consider remote mounting: Instead of mounting the desiccant breather directly to the reservoir, add a short length of pipe between the reservoir and breather. This helps keep the breather clear of oil mist, foam, or splashing that could blind the filter.
• Train technicians: Make sure technicians understand the proper operation and maintenance of desiccant breathers.

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