Shaft for viscous sealant systems

Abstract

A sealing system for sealing between an aperture of a machine housing and a rotating machine-shaft protruding through the aperture, said sealing system comprising: (i) a stuffing box for encasing the aperture of the machine housing and a segment of said shaft and, (ii) a viscous fluid type sealant within said stuffing box, wherein the shaft is concentric about its axis of rotation and said segment has at least one variation in its effective external diameter thereby increasing the surface area thereof, in contact with the liquid sealant.

1 . A sealing system for sealing between an aperture of a machine housing and a rotating machine-shaft protruding through the aperture, said sealing system comprising: (i) a stuffing box for encasing the aperture of the machine housing and a segment of said shaft and, (ii) a viscous fluid type sealant within said stuffing box, wherein the shaft is concentric about its axis of rotation and said segment has at least one variation in its effective external diameter thereby increasing the surface area thereof, in contact with the viscous sealant. 
   
   
       2 . The sealing system of  claim 1 , wherein at least one of the following limitations applies:
 a) said segment has at least two variations in its external diameter;   b) the effective external diameter of the shaft varies stepwise along at least a section of the segment;   c) the effective external diameter of the shaft varies continuously along at least a section of the segment.   
   
   
       3 . The sealing system of  claim 1 , wherein the segment of the shaft has a cross-section along said axis having a profile selected from the group comprising crenellated, sinusoidal, dog-tooth, and jagged profiles. 
   
   
       4 . The sealing system of  claim 3 , wherein at least one of the following limitations applies:
 a) at least one change in direction along the profile is smoothed by beveling or curving;   b) the profile is formed on the segment of the shaft by turning the shaft on a lathe;   c) the profile is fixed to the shaft.   
   
   
       5 . The sealing system of  claim 4 , wherein c) the profile is fixed by means selected from the group comprising gluing and press-fitting. 
   
   
       6 . The sealing system of  claim 1 , wherein the shaft is cylindrical and the segment further comprises a sheath affixed around the shaft to rotate therewith, the sheath having at least one variation in external diameter along the segment thereby increasing the surface area thereof in contact with the high viscosity liquid sealant. 
   
   
       7 . The sealing system of  claim 6 , wherein at least one of the following limitations applies:
 a) the sheath being sealed to the drive shaft to prevent leakage along the sheath-shaft interface;   b) the effective external diameter of the sheath varies stepwise along at least a section of the segment;   c) the effective external diameter of the sheath varies continuously along at least a section of the segment;   d) the segment of the sheath has a cross section along said axis having a profile selected from the group comprising crenellated, sinusoidal, dog-tooth, and jagged profiles;   
   
   
       8 . The sealing system of  claim 1 , further comprising a conduit for a cooling fluid for cooling the sealant. 
   
   
       9 . The sealing system of  claim 8 , wherein at least one of the following limitations applies:
 a) the conduit passes through the sealant within the stuffing box;   b) the conduit passes around the inside of the stuffing box;   c) the sealing system further comprises an inner sleeve for lining at least part of the stuffing box.   
   
   
       10 . The sealing system of  claim 9 , wherein c) the conduit is defined by an inner surface of the stuffing box and an outer surface of the sleeve. 
   
   
       11 . The sealing system of  claim 10 , wherein the conduit is further defined by spacer ribs between the inner surface of said stuffing box and the outer surface of the sleeve. 
   
   
       12 . The sealing system of  claim 1 , for retrofitting into an existing stuffing box. 
   
   
       13 . The improved sealing system of  claim 1 , further comprising a pressurizable sealant injector in fluid contact with the stuffing box for injecting sealant at a desired pressure thereinto. 
   
   
       14 . The improved sealing system of  claim 13 , wherein the sealant injector comprises a barrel and is configured to be loadable by a replacement sealant cartridge that may be inserted into the barrel. 
   
   
       15 . The improved sealing system of  claim 14 , wherein the replacement sealant cartridge comprises a tube filled with the sealant. 
   
   
       16 . The improved sealing system of  claim 13 , wherein the sealant injector is coupled to the stuffing box by a sealant injection conduit whose outlet is asymmetrical to the stuffing box. 
   
   
       17 . The sealing system of  claim 1  further comprising sealing rings at each end of the stuffing box. 
   
   
       18 . The sealing system of  claim 1 , further comprising a lip extending radially from a proximal end of the segment of the shaft towards the stuffing box, to serve as a support for a proximal sealing ring. 
   
   
       19 . The sealing system of  claim 6 , further comprising a lip around the shaft extending from a proximal end of the sheath towards the stuffing box, to serve as a base for a sealing ring. 
   
   
       20 . The sealing system of  claim 6 , further comprising a lip extending radially inwards from the stuffing box towards the shaft, the lip having a radial rim around an inner circumference thereof protruding into the stuffing box, the rim for surrounding the shaft towards a proximal end of the sheath therearound.