2200LZJE-HO-C6-N_2013.12.
Chapter 2 Configuration and Specifications of Compressor
Compound 2-stage Screw Compressor 2016**C
2.5
Mechanisms
2-10
2.5 Mechanisms
2.5.1 Basics of the Screw Compressor
The screw compressor is categorized as a positive displacement rotary compressor. It has features of
both reciprocating and centrifugal compressors.
As shown in Figure 2-7, the refrigerant (gas) is continuously compressed by the 3-dimensional spaces
that are formed by a pair of male and female screw rotors (with different sectional profiles) and the
casing, as the spaces change continuously.
The rotor having 4 protruding tooth profiles is called a male or M rotor, and the rotor having 6 concave
profiles is called a female or F rotor. In this manual, they are referred to as M rotor and F rotor.
The compressor is driven by the motor connected to the shaft of the M rotor.
Figure 2-7 Compressor Mechanism
2.5.2 Suction
Process
As shown in Figure 2-8, the rotors with different tooth profiles are engaged. As the rotors turn, the
volume between the M and F rotor tooth profiles and the compressor casing gradually increases
starting from the suction side.
As the rotation continues, at a certain point when the volume reaches its maximum, the rotors isolate
the gas (volume), which is enclosed by the rotors and the compressor casing, from the suction port and
then continues rotation.
Figure 2-8 Suction Process
