Refrigerating Compressor; Condenser; Filter Dryer; Capillary Tube - pilotair ACT 3T User’s Maintenance & Spare Parts Manual

7.4 Refrigerating Compressor

The refrigerating compressor is the pump in the system, gas coming from the evaporator (low pressure side) is
compressed up to the condensation pressure (high pressure side). The compressors utilized are manufactured
by leading manufacturers and are designed for applications where high compression ratios and wide
temperature changes are present.
The hermetically sealed construction is perfectly gas tight, ensuring high-energy efficiency and long, useful life.
Dumping springs support the pumping unit in order to reduce the acoustic emission and the vibration diffusion.
The aspirated refrigerant gas, flowing through the coils before reaching the compression cylinders cools the
electric motor. The thermal protection protects the compressor from overheating and over currents. The
protection is automatically restored as soon as the nominal temperature conditions are reached.

7.5 Condenser

The condenser is the component in which the gas coming from the compressor is cooled down and condensed
becoming a liquid. Mechanically, a serpentine copper tubing circuit (with the gas flowing inside) is encapsulated
in an aluminum fin package.
The cooling operation occurs via a high efficiency fan, creating airflow within the dryer, moving air through the
fin package. It's mandatory that the ambient air temperature does not exceed the nominal values. It is also
important to keep the condenser unit free from dust and other impurities.
7.6

Filter dryer

Traces of humidity and slag can accumulate inside the refrigerant circuit. Long periods of use can also produce
sludge. This can limit the lubrication efficiency of the compressor and clog the expansion valve or capillary tube.
The function of the filter drier, located before the capillary tubing, is to eliminate any impurities from circulating
through the system.
7.7

Capillary tube

It consists of a piece of reduced cross section copper tubing located between the condenser and the evaporator,
acting as a metering device to reduce the pressure of the refrigerant. Reduction of pressure is a design function
to achieve optimum temperature reached within the evaporator: the smaller the capillary tube outlet pressure,
the lower the evaporation temperature.
The length and interior diameter of the capillary tubing is accurately sized to establish the performance of the
dryer; no maintenance or adjustment is necessary.
7.8

Alu-Dry module

The heat exchanger module houses the air-to-air, the air-to-refrigerant heat exchangers and the demister type
condensate separator. The counter flow of compressed air in the air-to-air heat exchanger ensures maximum
heat transfer. The generous cross section of flow channel within the heat exchanger module leads to low
velocities and reduced power requirements. The generous dimensions of the air-to-refrigerant heat exchanger
plus the counter flow gas flow allows full and complete evaporation of the refrigerant (preventing liquid return to
the compressor). The high efficiency condensate separator is located within the heat exchanger module. No
maintenance is required and the coalescing effect results in a high degree of moisture separation.
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Technical Description
7425MUM217_EN_05.0