Motor Grounding Seal

Abstract

A shaft seal assembly is disclosed having a stator including a main body and axial and radial projections therefrom. The rotor is radially extended and encompasses the axial and radial projections from said stator. A passageway formed between the radial projection of stator and rotor results in an axial passageway having its opening facing rearwardly from the rotor and away from the source of impinging coolant and/or contaminant. A concentric circumferential receptor groove in the stator facing the housing allows insertion of conductive means for transmission of electrostatic charge away from the shaft through the shaft seal assembly to the housing and ground. The receptor groove is opposite the axial passageway and provides for both a substantially lower contaminant environment and improved engagement with conductive means.

1 . A labyrinth type seal for sealing a rotatable shaft entering a grounded housing comprising:
 a) a housing;   b) a stator surrounding a shaft and affixed to the housing, said stator having a main body and projections extending both axially and radially beyond said main body, said radial projections being greater than said axial projection;   c) a rotor surrounding said shaft and rotatively connected to said shaft; said rotor having a main body and projections extending both radially and axially;   d) a circular circumferential receptor groove placed within the rotor and facing said shaft;   e) a circumferential conductive means, said conductive means placed within said receptor groove and engaged with said shaft to conduct electrical currents away from said shaft to said grounded housing; and   f) said rotor and said stator abutted and intermeshed with each other on said shaft, said rotor radial projections extending radially outwardly farther than any radial projections of said stator.   
     
     
         2 . A seal accordance to  claim 1  wherein the radial space between said radial rotor projections and said radial stator projections forms a first axial passage. 
     
     
         3 . A seal in accordance with  claim 2 , wherein said first passageway includes a first axial passage opening to a space in said stator and facing the body of the stator between said housing and the radial extensions of the rotor and stator. 
     
     
         4 . A seal in accordance with  claim 3 , wherein said dimension of said axial passage is constant. 
     
     
         5 . A seal in accordance with  claim 4 , wherein the dimension of said axial passage is predetermined. 
     
     
         6 . A seal in accordance with  claim 3 , wherein said opening of said axial passage faces away from injected coolant, said rotor projection and towards said housing. 
     
     
         7 . A seal accordance with  claim 2 , wherein said main body of said stator surrounds a portion of said rotor. 
     
     
         8 . A seal in accordance with  claim 2 , wherein the radius of the radial internal surface of the rotor radial projection encompassing said stator is greater than the radius of the exterior surface of said radial projection of said stator. 
     
     
         9 . A seal in accordance with  claim 1 , wherein there is at least one labyrinth formed between the main body of said stator and the main body of said rotor. 
     
     
         10 . A seal in accordance with  claim 1 , wherein said rotor and said stator are restrained from relative axial movement between each other. 
     
     
         11 . A seal in accordance with  claim 1 , wherein a groove is formed in said main body of said stator, said groove augmenting the radial extension of said radial projection from said stator. 
     
     
         12 . A shaft seal assembly as described in  claim 1  wherein the conductive means promotes conduction of shaft voltage and is selected from the group consisting of fibrous conductive brushes, a metallic insert with solid conductor ring, an electrically conductive insert ring having a metallic base and a solid conductive ring and combinations thereof. 
     
     
         13 . A labyrinth type seal for sealing a rotatable shaft entering a grounded housing comprising:
 a. a grounded housing;   b. a stator surrounding a shaft and affixed to the housing, said stator having a main body and projections extending both axially and radially beyond said main body, said radial projections being greater than said axial projection;   c. a rotor surrounding said shaft and rotatively connected to said shaft; said rotor having a main body and projections extending both radially and axially;   d. a circular circumferential receptor groove placed within the rotor and facing said shaft;   e. a circumferential brush ring having an annular frame, said frame including:
 i. first and second frame members defining an annular channel; 
 ii. a plurality of electrically conductive filament brushes electrically connected to said annular frame, said filament brushes being sufficiently small to induce ionization in the presence of an electrical field, said filament brushes being retained between said first and second frame members and having distal end portions disposed in said channel; 
   f. wherein said electrical charges produced through ionization are collected for conduction through said filament brushes to and through said annular frame, to and through said stator and to said grounded housing, away from said shaft; and   g. said rotor and said stator are abutted and intermeshed with each other on said shaft, said rotor radial projections extending radially outwardly farther than any radial projections of said stator.   
     
     
         14 . A seal in accordance with  claim 13  wherein the radial space between said radial rotor projections and said radial stator projections forms a first axial passage. 
     
     
         15 . A seal in accordance with  claim 14 , wherein said first passageway includes a first axial passage opening to a space in said stator and facing the body of the stator between said housing and the radial extensions of said rotor and said stator. 
     
     
         16 . A seal in accordance with  claim 15 , wherein said dimension of said axial passage is constant. 
     
     
         17 . A seal in accordance with  claim 16 , wherein the dimension of said axial passage is predetermined. 
     
     
         18 . A seal in accordance with  claim 15 , wherein said opening of said axial passage faces away from injected coolant, said rotor projection and towards said housing. 
     
     
         19 . A seal accordance with  claim 14 , wherein said main body of said stator surrounds a portion of said rotor. 
     
     
         20 . A seal in accordance with  claim 14 , wherein the radius of the radial internal surface of the rotor radial projection encompassing said stator is greater than the radius of the exterior surface of said radial projection of said stator. 
     
     
         21 . A seal in accordance with  claim 13 , wherein there is at least one labyrinth formed between the main body of said stator and the main body of said rotor. 
     
     
         22 . A method of sealing a shaft exiting a grounded housing and conducting electrostatic charge away from said shaft to the grounded housing, the method comprising:
 a. fixing a stator having a main body and a projection extending both radially and axially beyond the main body of said stator concentrically about the shaft wherein the radial projections are greater than the axial projection;   b. mounting a rotor sealed on the shaft in close relation to the housing for rotation with the shaft and providing the rotor with radial projections extending radially outwardly farther than any radial projections of said stator and said rotor encompassing the radial extremity of the radial projection of the stator and having overlapping radially spaced surfaces forming an axial passage between the surfaces of the rotor and the stator projections, wherein said opening of said axial passage faces away from said rotor and toward the body of said stator;   c. mounting a conductive means within said rotor to engage said shaft and promote transmission of shaft voltage bearing currents; and   d. transmitting said shaft voltage from said shaft through said conductive means, said rotor and said grounded housing.