Refrigeration System; Compressor - wsm STW37 Workshop Manual

STW34, STW37, STW40, WSM

2. REFRIGERATION SYSTEM

[1] COMPRESSOR

Compressor Oil
The compressor oil dissolves in the refrigerant, circulates through the air-conditioning cycle, and functions to
lubricate the compressor. But the conventional compressor oil for R12 does not dissolve in R134a, so it does not
circulate through the cycle, and the lifespan of the compressor is considerably shortened.
It is still essential to ensure that the correct refrigerant oil is used. R12 systems were lubricated with mineral oil,
which is totally unsuitable for R134a systems. The letter require PAG oil, which mixes very well with the refrigerant
and provides ideal lubrication throughout the system.
Quantity (Total)
110 to 120 cc
0.116 to 0.126 U.S.qts
0.0968 to 0.105 Imp.qts
*PAG: Polyalkyleneglycol (Synthetic oil)
Brand Name
ND-OIL 8 <PAG* oil>
10-M3
The vane type compressor installed on this cabin
consists of a cylinder (1) with an oval cross section and
a rotor (2) with five vanes (3). The vane type compressor
is provided with two suction ports and two discharge
ports respectively.
The five vanes (3) mounted on the rotor (2), rotating
along the inner wall of the cylinder (1), keeps
air-tightness using the centrifugal force of the rotor (2)
and the back pressure of the vanes (3) that grow in
proportion to the rotating speed of the rotor (2).
As a result, the volumes of the five cylinder
chambers separated with the cylinder (1) and the five
vanes (3) change.
For each rotation of the rotor (2), each of the cylinder
chambers performs two
compression, and discharge.
(1) Cylinder
(2) Rotor
Operation
In proportion to the rotation of the rotor (3), a volume
of a cylinder chamber separated with the cylinder (1) and
the vanes (4) increases. The cylinder chamber inhales
refrigerant gas from the suction port (2).
As the rotor (3) rotates further, a volume of the
cylinder chamber separated with the cylinder (1) and the
vanes (4) decreases, and the refrigerant gas is
compressed. As the rotor (3) rotates even further, the
refrigerant gas is highly compressed and then presses
the discharge valve to open. The refrigerant gas is
discharged from the discharge port (5).
(1) Cylinder
(2) Suction Port
(3) Rotor
(4) Vane
(5) Discharge Port
CABIN
cycles of inhalation,
(3) Vane
9Y1211109CAM0002US0
(A) Compression Process
(B) Discharge Process
(C) Suction Process
9Y1211109CAM0003US0
9Y1211109CAM0004US0
KiSC issued 11, 2014 A