AIR CONDITIONING AND HEATING SYSTEM CONTINUED
The orifice tube assembly (Figure 2, Item 1) contains a plastic body, two screens (Figure 2, Item 4), and a small
brass tube. The small brass tube is referred to as an orifice tube (Figure 2, Item 2), and it is located in the center of
the body. The O-ring seals (Figure 2, Item 3) are positioned on the body of the orifice tube to seal against leakage
around the orifice tube.
The orifice tube assembly is contained within the in-line dryer.
The orifice tube (Figure 2, Item 2) restricts the flow of refrigerant. This restriction creates a pressure drop across
the orifice tube. This changes the refrigerant from a high temperature high pressure liquid into a liquid vapor
mixture that is low temperature and low pressure. The flow rate is controlled by the pressure difference across the
Figure 2. Orifice Tube.
Low temperature and low pressure refrigerant leaves the evaporator coil and passes into the accumulator
(Figure 3, Item 1) through the inlet (Figure 3, Item 2). Liquid refrigerant that was not evaporated in the evaporator is
stored in the bottom of the accumulator. Vapor refrigerant passes through the standpipe (Figure 3, Item 3) before
exiting through the outlet (Figure 3, Item 5). The oil goes to the compressor through a filter for the oil drain
(Figure 3, Item 4).
The accumulator stores some refrigerant in order to compensate for the changing system demands. These system
demands can result from changing speeds in the compressor, varying heat loads, or small losses of refrigerant.
Figure 3. Accumulator.