US Patent 7674099 Compressor with oil bypass

An oil lubricated compressor which includes a bypass oil line connecting respective oil paths upstream and downstream of the motor. The bypass oil path permits oil to be detoured around the motor in a tube that is external to the compressor shell and flows back into the shell near the scroll inlet. The oil bypass line returns “excess” oil directly to sump 28, rather than having it flow from sump 27 to sump 28 through an air-gap, thereby reducing both the drag on the motor and the input power.