Magnet pump with rear thrust bearing member

Claim 1

A magnet pump, comprising: a front casing defining an inner pump chamber and having an axially extending suction port and a circumferentially extending discharge port; an impeller rotatably mounted in the pump chamber, the impeller having a front side portion and a rear side portion opposite to the front side portion, said front side portion facing the suction port; a cylindrical rear casing cooperating with the front casing to enclose the inner pump chamber fluid tight; a drive rotor mounted outside the rear casing and having a drive magnet; a driven rotor having a front side portion on which the impeller is mounted, and a driven magnet facing and forming a magnetic coupling with the drive magnet and rotatable in unison with the impeller; a spindle secured to the rear casing, said spindle having an extended end portion axially projecting toward the suction port and supporting the driven rotor and the impeller rotatably thereon and movable in the axial direction thereof; and a rear thrust bearing member for supporting a rearward thrust which acts on the driven rotor and the impeller in a direction opposite to the direction facing the suction port, wherein said spindle having an axial end face at the extended end portion, and said rear thrust bearing member being disposed to be in frictional contact with said axial end face of the spindle in the event of at least one of an idling operation of the pump and an abnormal operation thereof.