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Problem

Dirt particles as small as 5 microns can easily damage bearings and gears in equipment. Unfortunately, gearbox vents and hydraulic breather caps only prevent particles larger than 25-45 microns from being ingested into machinery from the surrounding air.   As a result, those large particles are broken down into much smaller particles resulting in premature equipment damage. For example, one teaspoon of dirt in a 55 gallon drum of lubricant can create one billion particles that are 4 microns or larger in diameter in that same drum. Imagine how much damage this can cause in equipment, leading to unwanted maintenance downtime.

Additionally, these vents and caps provide no protection from moisture ingress into equipment. Water is one of primary defect sources for industrial machinery.

Solution: Install good quality desiccant breathers on your equipment

A good quality desiccant breather has a 3 micron filter as part of the design to help prevent harmful particles from being introduced into equipment. As a result, premature equipment failures, loss of capacity and unneeded maintenance expenses will largely be prevented.

Additionally, desiccant breathers provide an insight into the equipment health through how the desiccant is being spent.

It is very important to have good quality desiccant breathers installed on equipment to prevent the introduction of equipment defects and help improve your return on assets.

Desiccant Breather Assessment

• If the top of the desiccant breather is pink there is an internal moisture source from the reservoir headspace.
• If the bottom of desiccant breather turns pink first then there is an external moisture source from the outside environment.
• If the desiccant breather turns amber or brown instead of pink, then it is likely an indication of oil misting.
• If the breather has turned completely pink then the desiccant is spent and the breather is at full water saturation.
• Reservoir water content: If the breather changes quickly from blue to pink when first installed, then the breather is likely working to remove water already in the system. It may take two to three breathers to dry the headspace before the breather begins operating normally.
• Sizing: If breathers continue to spend quickly, the size may not be appropriate for the application.

Things to check if your breather is not spending at all

• Dry Environment: If the environment has been abnormally dry there may not be enough ambient moisture for the silica to adsorb.
• Breather Size: The breather may be larger than what is required for the system. Check the recommended system sizing. The breather should be changed after one year, regardless of visible condition, to renew particle filtration.
• Intake Holes: Check that the proper number of plugs have been removed. Instructions on the breather packaging indicate how many holes are needed for various air flow requirements.

Note: The actual color changes above will vary depending on the supplier of the desiccant breather. All breathers will have some type of color change indicating condition. The above colors are applicable to two well-known desiccant breather manufacturers.

Desiccant Breather Air Vent Plugs

• Some combination of air vents should always be pulled depending on the air flow in the machine. This is a common mistake when installing breathers.
• If the CFM is greater than 12-16 CFM you should pull all of the air vents from the breather.
• When selecting a breather, always select a model with a CFM rating greater than the CFM requirements of the application.
• Breathers should not be selected by the size of the tank or reservoir. Breather size is always determined by the maximum fluid movement in/out of the fluid reservoir.
• Not all equipment, for example gearboxes, may specify a CFM value. If needed you can use this rule of thumb o calculate the CFM and select the correct breather for the application:
  7.5 GPM = 1 CFM.
  CFM = GPM/ 7.5.

Learn more about Lubrication Best Practices and desiccant breathers from Paul Llewellyn at our Rethink Maintenance Training Roadshows