Expansion Block/Orifice Tube: Description and Operation
TUBE-A/C ORIFICEDESCRIPTION
The fixed A/C orifice tube is installed in the A/C liquid line and provides a restriction in the liquid refrigerant line between the A/C condenser and the A/C evaporator. This restriction established the pressure differential between the high and low-pressure sides of the A/C system.
The A/C orifice tube includes a diffuser screen (1), O-ring seals (2) to seal it to the inner wall of the A/C liquid line, an inlet filter screen (3) and the fixed orifice (4).
OPERATION
The fixed A/C orifice tube is used to meter the flow of liquid refrigerant into the A/C evaporator. The high-pressure liquid refrigerant from the A/C condenser expands into a low-pressure liquid as it passes through the metering orifice and diffuser screen of the A/C orifice tube.
The A/C orifice tube is not serviceable and cannot be repaired and, if faulty or plugged, the A/C liquid line must be replaced.