Seal arrangement for mill roll

In combination, a housing having a substantially horizontally oriented opening extending inwardly from an end face thereof, a rotatable stub shaft projecting coaxially into said opening, a bearing assembly disposed adjacent the inner end of said opening and rotatably supporting said stub shaft with respect to said housing, and an isolator assembly disposed adjacent the outer end of said opening and coacting between said stub shaft and said housing for isolating said bearing assembly from the external environment disposed adjacent the end face of the housing, the improvement comprising:

• said isolator assembly including a first isolator ring substantially concentric with and nonrotatably mounted on said stub shaft, said first isolator ring being disposed within said opening but axially outwardly from said bearing assembly, said first isolator ring having a main sleeve part which closely surrounds and is sealingly engaged with said stub shaft;
• said isolator assembly including a second isolator ring disposed concentric with said opening and fixed to said housing, said second isolator ring including a sleevelike hub coaxially disposed within and nonrotatably and sealingly coupled to said housing, said hub substantially concentrically surrounding the sleeve part of said first ring, said hub having a stepped bore formed coaxially therein in which is positioned said first ring, said stepped bore including a first bore extending coaxially inwardly from the outer end thereof and a second bore projecting coaxially inwardly from the inner end of said first bore, said first bore being of larger diameter than said second bore and a substantially radially-extending annular endwall extending between the adjacent ends of said first and second bores, said second ring having an interior annular wall as defined by said second bore which concentrically surrounds an exterior annular wall defined on said main sleeve part so as to define a first annular clearance space therebetween;
• said isolator assembly including a third isolator ring which surrounds said stub shaft but is fixed to said housing in concentric relationship with said opening, said third ring including an annular flange which projects radially outwardly so as to overlap said end surface of said housing, and fasteners for securing said third ring to said housing, said second and third rings being fixedly joined together;
• said third ring having a sleevelike portion which is fixed to said flange and projects axially therefrom toward the main sleeve part of said first ring, said sleevelike portion having an end surface thereon which is disposed adjacent but spaced from an opposed end surface formed on said main sleeve part, said sleevelike portion having an inner annular wall which closely and substantially concentrically surrounds said stub shaft to define a second annular clearance space therebetween which is of narrow radial but substantial axial extent, said second clearance space at the axially outer end thereof communicating with the surrounding environment and at the axial inner end thereof communicating with a radial clearance space between the sleevelike portion and sleeve part, said sleevelike portion being concentrically disposed within and having an outer annular surface which is of substantially smaller diameter than said first bore so as to define therebetween an annular chamber of substantial radial and axial extent, the axially outer end of said chamber being closed by the flange of said third ring;
• said first ring having a sleevelike flange part which projects axially outwardly from said main sleeve part so as to project into said annular chamber, the free end of said flange part being spaced from the outer axial end wall of said chamber, said flange part having an inner annular wall which closely and concentrically surrounds the outer annular wall on the sleevelike portion to define a third annular clearance space of small radial but substantial axial extent, said flange part having an outer annular surface which is concentrically spaced inwardly a substantial radial extent from the wall of the first bore so as to define an annular collection chamber therebetween of substantial axial and radial extent;
• one of said rings defining drain opening means communicating with the lower portion of said collection chamber for permitting external drainage of fluid therefrom;
• and
• said first ring having an annular damlike wall which projects radially outwardly and is disposed adjacent and defines the axially inner end of said collection chamber, said damlike wall having an outer peripheral wall which is spaced a slight distance from the wall of said first bore whereby said annular damlike wall projects radially outwardly a substantial extent beyond the diameter of said second bore, and the damlike wall having a radial wall on the inner axial side thereof which is disposed closely adjacent and directly opposite the radial end wall on said second ring, whereby these opposed and closely adjacent radial walls define a narrow clearance passage therebetween which at the radially inner edge thereof communicates with the outer axial end of said first clearance space.