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type of strain the lubricant may be subjected
to while in service. Typically, lubricant
stressors in compressors include moisture,
extreme heat, compressed gas and air, metal
particles, gas solubility, and hot discharge
surfaces. Keep in mind that when gas is
compressed, it can have adverse effects on the
lubricant and result in a noticeable decline in
viscosity along with evaporation, oxidation,
carbon depositing and condensation from
moisture accumulation.
Once you are aware of the key concerns
that may be introduced to the lubricant, you
can use this information to narrow your
selection for an ideal compressor lubricant.
Characteristics of a strong candidate lubri-
cant would include good oxidation stability,
anti-wear and corrosion inhibitor additives,
and demulsibility properties. Synthetic base
stocks may also perform better in wider
temperature ranges.
Lubricant Selection
Ensuring you have the proper lubricant will
be critical in the health of the compressor. e
first step is to reference the recommendations
from the original equipment manufacturer
(OEM). Compressor lubricant viscosities and
the internal components being lubricated can
vary greatly based on the type of compressor.
e manufacturer's suggestions can provide a
good starting point.
Next, consider the gas being compressed,
as it can significantly affect the lubricant. Air
compression may lead to issues with elevated
lubricant temperatures. Hydrocarbon gases
tend to dissolve lubricants and, in turn, grad-
ually lower the viscosity. Chemically inert
gases such as carbon dioxide and ammonia
may react with the lubricant and decrease the
viscosity as well as create soaps in the system.
Chemically active gases like oxygen, chlorine,
sulfur dioxide and hydrogen sulfide can form
tacky deposits or become extremely corrosive
when too much moisture is in the lubricant.
You should also take into account the
environment to which the compressor
lubricant is subjected. is may include the
ambient temperature, operating temperature,
surrounding airborne contaminants, whether
the compressor is inside and covered or outside
and exposed to inclement weather, as well as
the industry in which it is employed.
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