Humidity relative
The relative humidity of a gas (or air) vapor mixture as a ratio of the partial pressure of vapor to
vapor saturation pressure at the dry bulb temperature of the mixture
Inlet pressure
Total pressure (static plus velocity) at the inlet flange of the compressor
Inlet temperature
Temperature at the inlet flange of the compressor
Leak air
A crack or hole that accidentally admits a gas or lets it escape
Maximum operating pressure
Highest operating pressure system or component designed to withstand
Mayonnaise
An oily condensate discharged by lubricated air compressors. The term derived from the
appearance of condensate under normal conditions oily condensate should just be cloudy, like a
small amount of milk in a bucket of water. When a lubricated compressor begins to fail, then the
condensate becomes thick and sticky, in fact almost identical in appearance to term it has been
given
Membrane dryer
Reduce dew point by passing compressed air through a bundle of hollow membrane fibers; water
vapor and a portion of the compressed air then permeate the membrane walls and vent to
atmosphere
Micron
Micrometer or one millionth of a meter; micron is sometimes represented in filtration by the Greek
letter µ (mu) A micron is 0 000039" Contaminate particles are measured by micron size and
count
Micron rating
A measurement applied to filters or filter media to indicate removal of particle size at which
suspended solids above that size
Micro Logic Timer
An electronic timer and coil assembly designed to cycle SFD air dyers
Molecular sieves
A solid adsorbent used for drying compressed air
Molecular theory
All matter consists of molecules that are in constant motion and held together by molecular forces.
In a solid, the molecules are closely packed and arranged in such a pattern that the influence of the
molecular forces is very strong. This gives the solid its consistency and form. Molecular motion
consists largely of oscillations around points of equilibrium. In a liquid, the molecules are about
as close as in a solid, but not arranged in a lattice and the cohesive forces are weaker. The
molecules are more mobile in relation to each other, whereby the characteristic liquid phase
develops; the liquid accommodated itself to the walls of the containing vessel, and its free surface
aligns itself horizontally in response to the force of gravity. In a gas, however, the molecules are
farther apart, and they move freely about each other since the molecular forces are not as strong.
A gas therefore expands through space and mixes with other gasses present. The total volume of
the molecules in a gas is very small in relation to the volume of the gas. A gas, therefore may be
compressed into a small part of its original volume.
55
