Komatsu PC200-8M0 Shop Manual page 1171

100 Air conditioner
Air conditioner unit
Expansion valve
A: When evaporator outlet temperature is high
B: When evaporator outlet temperature is low
C: From receiver drier (high-pressure refrigerant)
D: To compressor (low-pressure refrigerant)
1. Expansion valve
1a. Needle valve
1a-1. Diaphragm
1a-2. Thermoprobe
1b. Spring
2. Refrigerant gas
3. Evaporator
Outline
q The expansion valve converts high-pressure
and high-temperature liquid refrigerant from the
receiver drier to low-pressure, low-temperature
misty refrigerant through the throttle action.
q It controls the flow rate of refrigerant by changing
the level of throttling depending on the tempera-
ture in the cab.
q The temperature of the air blown out of the air
vent is adjusted depending on the volume of re-
frigerant circulating in the evaporator (3).
PC200, 200LC, 220, 220LC-8M0
Structure
q Box-type expansion valve (1) consists of needle
valve (1a), spring (1b), etc.
Refrigerant gas (2) is sealed in the diaphragm
q
chamber (hatched area) outside diaphragm
(1a-1) of needle valve (1a).
SEN06151-00
13
80-100