Rotary compressor or pump

A fluid pressurizing device comprising:

• a fixed cylindrical casing,
• a rotor in said casing, said rotor having an externally driven input shaft extending rotatably and coaxially in said casing, said rotor including a plurality of piston chambers and respective pistons in said piston chambers, said pistons being reciprocable in said chambers along axes spaced radially from an axis of rotation of said input shaft and said pistons each having a piston rod connected to a crankshaft connected to said rotor for rotation therewith,
• said casing having fluid suction and discharge ports communicating sequentially with said piston chambers during rotation of said rotor to admit fluid through said suction ports and discharge pressurized fluid from said discharge ports,
• a valve member on each said piston chamber to provide respective communication between said suction and discharge ports and the respective said piston chamber, said valve member having a cylindrically shaped end corresponding to said cylindrical casing to close said ports when said valve member is closed, and
• a drive train synchronizing rotation of said crankshafts and said input shaft, said drive train comprising a fixed annular gear secured to said casing and pinion gears on said crankshafts in mesh with said fixed annular gear,
• said pistons undergoing reciprocal movement in said piston chambers in synchronism in which the pistons have the same stroke position in said chambers.