Abstract: A rotary machine, such as a horizontally oriented scroll type refrigerant compressor is disclosed. The compressor includes a compressor housing, an inner block fixedly disposed within the compressor housing, a drive shaft extending substantially in the horizontal direction, and a driven mechanism, such as a compression mechanism operatively connected to one end of the drive shaft. The drive shaft is rotatably supported by the inner block and the compressor housing. A shielding element, such as an annular cylindrical member is fixedly held between the inner block and the compressor housing to prevent the drive shaft from passing through an oil sump of the housing. An internal lubrication oil pump is formed by the elements which are associated with the drive shaft, and is operated by virtue of the rotational motion of the drive shaft in order to supply the lubrication oil from the oil sump to the frictional surfaces of the internal component parts of the compressor.