PUMP AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a pump having excellent corrosion resistance and wear resistance and high reliability even when treating water having high dissolved oxygen concentration and water containing large amount of solid suspended matter and to provide its manufacturing method. SOLUTION: A hard Cr plated membrane 8 is formed on sliding faces or fitting faces of a rotary shaft 3 constituting the pump, a sleeve 10 attached to a shaft sealing part of the shaft, and a plurality of impellers 4 attached to the shaft to form a flow passage, and resin or oxide is impregnated in the membrane. A WC-NiCr thermal spraying membrane or a Cr3C2-NiCr thermal spraying membrane may be formed instead of the hard Cr plated membrane 8 for covering. Furthermore, it is more effective when a Ni plated membrane or Ni alloy membrane covers a lower layer of the hard Cr plated membrane 8 or the WC-NiCr thermal spraying membrane or the Cr3C2-NiCr thermal spraying membrane. SiO2 or CrO2 can be used instead of resin. COPYRIGHT: (C)2007,JPO&INPIT