The only moving parts in a stationary blade rotary compressor are a steel ring, an eccentric or cam, and a sliding barrier (see Fig. 9-71). Figure 9-72 shows how the rotation of the off-center cam compresses the gas refrigerant in the cylinder of the rotary compressor. The cam is rotated by an electric motor. As the cam spins it carries the ring with it. The ring rolls on its outer rim around the wall of the cylinder.
To be brought into the chamber, the gas must have a pathway. Note that in Fig. 9-73 the vapor comes in from the freezer and goes out to the condenser through holes that have been drilled in the compressor frame. Note that an offset rotating ring compresses the gas. Figure 9-74 shows how the refrigerant vapor in the compressor is brought from the freezer. Then, the exit port is opening. When the compressor starts to draw in the vapor from the freezer the barrier is held against the ring by a spring.
This barrier separates the intake and exhaust ports. As the ring rolls around the cylinder it compresses the gas and passes it on to the condenser (see Fig. 9-75). The finish of the compression portion of the stroke or operation is shown in Fig. 9-76. The ring rotates around the cylinder wall. The spring tension of the barrier’s spring and the pressure of the
cam being driven by the electric motor hold it in place. This type of compressor is not used as much as the reciprocating hermetic type of compressor.