Miscellaneous Mechanical Components
The rotary compressor is adaptable to direct drive by induction motors or multicylinder gasoline
or diesel engines. The units are compact, relatively inexpensive, and require a minimum of
operating attention and maintenance. They occupy a fraction of the space and weight of a
reciprocating machine of equivalent capacity. Rotary compressor units are classified into three
general groups, slide vane-type, lobe-type, and liquid seal ring-type.
The rotary slide vane-type, as illustrated in Figure 3, has longitudinal vanes, sliding radially in
a slotted rotor mounted eccentrically in a cylinder. The centrifugal force carries the sliding
vanes against the cylindrical case with the vanes forming a number of individual longitudinal
cells in the eccentric annulus between the case and rotor. The suction port is located where the
longitudinal cells are largest. The size of each cell is reduced by the eccentricity of the rotor
as the vanes approach the discharge port, thus compressing the air.
Figure 3 Rotary Slide Vane Air Compressor