Canned pump

Abstract

In a magnet pump in which a cylinder 4 A integrated with a drive shaft 3 A and provided with a drive magnet M 1 on the inner circumferential side thereof is disposed outside a cylindrical can 2 A having a bottom and secured to a pump casing 1 A, and a rotor 6 A concentrically fitted over an impeller shaft 5 A and provided with a driven magnet M 2 on the outer circumferential side thereof is disposed inside the can 2 A, and the rotor 6 A rotates integrally with an impeller 7 A around the impeller shaft 5 A as the drive shaft 3 A rotates, by virtue of a magnetic attraction force generated between the drive magnet M 1 and the driven magnet M 2 , wherein the sliding contact members of the pump, a bushing 81 , a sleeve 82 and a thrust ring 83 interposed in each of the bearing sections 8 f A and 8 r A for the impeller shaft 5 A, are made of ceramic or cemented carbide and have a diamond-like carbon film.

1 . A canned pump in which drive magnetic force generating means disposed outside a can having a bottom, the can being hermetically sealed from an outside and an inside of the can being communicated with an inside of the pump, whereas a rotor concentrically fitted over an impeller shaft is disposed inside the can, and the rotor is rotated integrally with an impeller around the impeller shaft by virtue of magnetic action generated between the drive magnetic force generating means and the rotor, characterized in that a sliding contact member made of ceramic or cemented carbide and having a diamond-like carbon film on a sliding contact face thereof is interposed in a bearing section for the impeller shaft.  
   
   
       2 . A canned pump in accordance with  claim 1 , wherein the sliding contact member having the diamond-like carbon film is at least one selected from a bushing fitted into a bearing hole section, a sleeve fitted over the impeller shaft, and a thrust ring making contact with an end face of the bushing and/or the sleeve.  
   
   
       3 . A canned pump in accordance with  claim 1 , wherein liquid-flowing grooves are formed on the sliding contact face of the sliding contact member.  
   
   
       4 . A canned pump in accordance with  claim 1 , wherein the sliding contact member having the diamond-like carbon film is made of silicon carbide or tungsten carbide.  
   
   
       5 . A canned pump in accordance with  claim 1 , wherein a thickness of the diamond-like carbon film is in the range of about 0.1 to about 10 μm.  
   
   
       6 . A canned pump in accordance with  claim 1 , wherein a Vickers hardness of the sliding contact face having the diamond-like carbon film is in the range of about 900 to about 2500 Hv.  
   
   
       7 . A canned pump in accordance with  claim 1 , wherein the diamond-like carbon film is formed using a plasma ion implantation method.  
   
   
       8 . A canned pump in accordance with  claim 7 , wherein the plasma ion implantation method conforms to a radio-frequency high-voltage pulse superimposition system wherein a pulse radio-frequency power supply for pulse plasma generation and a negative high-voltage pulse power supply for ion implantation are superimposed to generate a plasma around a base material and to induce ions inside the plasma into the base material using high-voltage pulses.  
   
   
       9 . A canned pump in accordance with  claim 1 , wherein the drive magnetic force generating means is a cylinder integrated with a drive shaft and provided with a drive magnet on an inner circumferential side thereof, and a driven magnet is provided on an outer circumferential side of the rotor.  
   
   
       10 . A canned pump in accordance with  claim 1 , wherein the canned pump is a canned motor pump, the drive magnetic force generating means of which is a stator of a motor.