Fluid compressor with vertical longitudinal axis

摘要

A fluid compressor includes a piston which has a vertical longitudinal axis. A plurality of working chambers are provided between a cylinder and the piston, and are constituted by upper working chambers and lower working chambers which separated from each other by a center portion of the piston. Fluid is sucked in the lowermost one of the upper working chambers and the uppermost one of the lower working chambers, respectively, and is compressed while being conveyed. The diameter phi D3 of a lower shaft portion of the piston and the diameter phi D4 of an upper shaft portion of the piston have a relationship phi D3 < phi D4 in order to apply an upward thrust force to the piston.