JP2003083288A - Corrosionproof device for rotation main shaft of underwater rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosionproof device for a rotation main shaft of an underwater rotating machine providing excellent electrolytic corrosion protecting effect by sure electric conductivity between a rotor part and stator part and having excellent maintainability. SOLUTION: Inside an annular space section 6 formed on outer periphery of the rotation main shaft 1 in a casing or a housing 5 in the rear of the rotor 2 engaged with the rotation main shaft 1, a conductive brush 8 sliding on outer peripheral face of the rotation main shaft 1 or its protective sleeve 1s is borne on an elastic current-carrying ring. The elastic current-carrying ring 7 is engaged with an inner peripheral return groove 4 of a current-carrying ring holder 3 engaged with peripheral wall surface inside the annular space section 6.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submersible electric pump,
The present invention relates to a main shaft anticorrosion device for a submersible rotating machine such as a stirring device. 2. Description of the Related Art In a submersible rotary machine such as a submersible electric pump, corrosion is particularly likely to occur near a liquid-contacting portion or a gap between a rotating body portion and a stationary body portion. It has been clarified that the cause of the corrosion is due to the action of the corrosion battery formed on the metal surface and the action of the corrosion battery due to the contact between dissimilar metals, eliminating the potential difference between the anode and the cathode of the corrosion battery. If successful, the corrosion current will stop flowing and the corrosion will stop. Therefore, it is generally practiced to attach a galvanic anode to a stationary body that is in contact with liquid of a submersible rotating machine, for example, the outer surface of a head cover, and to apply an anticorrosion current to the entire area of the stationary body that is electrically connected to protect the stationary body. Have been However, the rotating spindle of a submersible rotating machine such as a submersible electric pump or an aeration / stirring device is supported by a bearing such as a ball bearing, and the gap between the opposing surfaces of the inner and outer rings of the bearing is filled with grease for lubrication. Since the grease is non-conductive, an insulating oil film is formed on the contact portion between the inner and outer rings and the ball when the rotating main shaft rotates, and the bearing inner ring and the rotating body portion connected thereto and the bearing outer ring and the stationary body portion connected thereto Is completely insulated from the rotating body part, and the anticorrosion current from the galvanic anode cannot flow into the rotating body part, and it is inevitable that corrosion occurs on the rotating main shaft due to a potential difference from the stationary body part. A large axial-flow or diagonal-flow pump in which an electric motor is installed on land and a part of the rotating spindle is exposed to the air,
As shown in FIG. 3, by bringing the sliding brush 108 into direct sliding contact with the air exposed portion of the rotating spindle 101, it is possible to secure electrical connection and prevent corrosion of the rotating spindle 101. However, in a submersible rotating machine such as a submersible electric pump, the electric motor part is completely submerged, so that the sliding brush is mounted inside the electric motor. Specifically, as shown in FIG. 4, the tip of the sliding brush 208 having the base fixed to the back surface of the head cover 211 is in sliding contact with the non-load-side lead-out portion of the rotating spindle 201. In such a conventional structure, the wear powder of the sliding brush 208 is generated by the rotor 21 of the electric motor.
2 and the stator 213 and into the non-load-side bearing 214, causing an obstacle to the motor. At the time of maintenance, the inside of the motor will be opened and implemented, and advanced technology is required, so repair and maintenance by bringing it to a maintenance shop is necessary. Absent. SUMMARY OF THE INVENTION An object of the present invention is to provide a reliable electrical conductivity between a rotating body portion and a stationary body portion to obtain an excellent effect of preventing electrolytic corrosion, and to improve maintenance. An object of the present invention is to provide an excellent anti-corrosion device for rotating spindles of underwater rotating machines. According to the present invention, there is provided an apparatus for protecting a rotating spindle of a submersible rotating machine according to the present invention, wherein a ring formed on the outer periphery of the rotating spindle in a casing or housing located behind a rotating body fitted to the rotating spindle. In the space, an energizing brush which is in sliding contact with the outer peripheral surface of the rotary spindle or its protective sleeve is supported by the elastic energizing ring, and the elastic energizing ring is returned to the inner circumference of the energizing ring holder fitted to the peripheral wall surface in the annular space. It was fitted in the groove. An embodiment will be described below with reference to FIGS. 1 and 2. FIG. Reference numeral 1 denotes a rotating main shaft made of an iron material such as stainless steel, and a rotating body 2 such as an impeller is mounted on a load-side lead end thereof. Reference numeral 3 denotes an energizing ring holder having an annular groove 4 on the inner peripheral surface. The energizing ring holder 3 is made of a material that is not easily corroded by seawater, such as stainless steel or carbon, and is electrically conductive. Specifically, in the casing or the housing 5 behind the boss 2b of the rotating body 2, it is fitted to the peripheral wall surface in the annular space 6 formed on the outer peripheral surface of the rotating main shaft 1 or its protective sleeve 1s. Numeral 7 denotes an elastic energizing ring which is bent into a partially circular shape and has a contraction elasticity in the inner diameter direction. The elastic energizing ring is made of an elastic material which is not easily corroded by seawater, such as stainless steel, and has an electric conductivity. 1 and the outer circumference of the protective sleeve 1s are fitted in the annular groove 4 of the energizing ring holder 3. Numeral 8 denotes an energizing brush, which is made of a material such as carbon which is hardly corroded by seawater, and which is excellent in energizing and sliding properties. Or, it comes into sliding contact with the outer peripheral surface of the protective sleeve 1s. A current carrying anode (not shown) made of a metal having a low potential such as an aluminum alloy is attached to a liquid contacting stationary body of the underwater rotating machine, for example, a head cover. By electrically connecting the rotary main shaft 1 and the casing or housing 5 in the manner described above,
During the operation of the underwater rotating machine, the potential difference between the rotating main shaft 1 and the rotating body portion connected thereto and the casing or housing 5 and the stationary body portion connected thereto is reduced, so that the corrosion current stops flowing and the elution of the galvanic anode occurs. The flow of the anticorrosion current is formed to cause the anticorrosion action. According to the apparatus of the present invention, a reliable electric conductivity is provided between the rotating body portion and the stationary body portion of a submersible rotating machine such as a submersible electric pump, and the excellent electric power of the rotating main shaft is provided. There is an advantage that an anti-corrosion effect can be obtained, and that maintenance can be easily performed at the pump usage site without having to open the inside of the motor during maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional side view of a main part of a submersible rotating machine provided with an anticorrosion device of the present invention. FIG. 2 is a plan view of an elastic conduction ring in the anticorrosion device of the present invention. FIG. 3 is an outer side view of a large-sized mixed flow pump in which a sliding brush is slidably brought into direct contact with an air exposed portion of a rotary spindle. FIG. 4 is a vertical sectional side view of a main part of an underwater rotary machine in which the tip end of a sliding brush fixed on the back surface of a head cover is brought into sliding contact with a non-load side of a rotary spindle. [Description of Signs] 1 rotating main shaft 1s protective sleeve 2 rotating body such as impeller 3 conducting ring holder 4 return groove 5 casing or housing 6 annular space 7 elastic conducting ring 8 conducting brush

Claims (1)

Claims: 1. An annular space formed around the outer periphery of a rotating main shaft in a casing or a housing located behind a rotating body fitted to the rotating main shaft. The energizing brush which is in sliding contact with the outer peripheral surface is supported by the elastic energizing ring, and the elastic energizing ring is inserted into the inner peripheral annular groove of the energizing ring holder fitted to the peripheral wall surface in the annular space. A rotating spindle anticorrosion device for a submersible rotating machine, which is fitted.