Mechanical seals with setting block for use with slurry pumps

Abstract

A mechanical seal assembly, especially for use in a slurry pump in which the seal rings are resiliently urged into sealing relation by at least one elastomeric assembly loaded in shear. The preferred embodiment is constructed as a carriage for installation and removal as a unit but it may also be constructed for installation in situ.

What is claimed is: 
     
       1. A mechanical seal assembly .[.especially.]. adapted for use with pumps .[.whose pump product is abrasive and which is operatively associated with.]. .Iadd.which includes .Iaddend.a pump housing .Iadd.having an attachment region .Iaddend.and a .[.motor-drive.]. shaft .Iadd.for .Iaddend.driving a pump impeller, said seal .Iadd.assembly .Iaddend.comprising: a rotatable seal ring operatively connected to and driven with said shaft;   a stationary seal ring operatively connected to said housing, each of said seal rings having a face opposing the face of the other seal ring and adapted to cooperate in sealing relation therewith.[.;.]. .Iadd.for retarding the flow of pump product from a high pressure region to a low pressure region extending along the shaft; and .Iaddend.   an elastomeric assembly supporting .Iadd.one of .Iaddend.said .[.rotatable.]. seal .[.ring.]. .Iadd.rings, .Iaddend.said elastomeric assembly including an annular member formed of elastomeric material, .[.and.]. a pair of concentric bands bonded thereto, .Iadd.at least one of said bands having an axially extending annular surface free of elastomeric material, .Iaddend.said bands being axially and radially spaced from each other, .Iadd.and means for detachably securing said free band surface and thus said elastomeric assembly to the attachment region within the pump in a manner whereby a static seal capable of withstanding high pressure is maintained between .Iaddend.said elastomeric assembly .[.,.]. .Iadd.and said region to prevent secondary leakage therebetween and such that .Iaddend.when .[.placed.]. .Iadd.arranged .Iaddend.in an operative position .[.on said drive shaft, urging said rotatable.]. .Iadd.the elastomeric assembly urges said one .Iaddend.seal ring toward .[.said stationary.]. .Iadd.the other of said .Iaddend.seal .[.ring.]. .Iadd.rings .Iaddend.and .[.being.]. .Iadd.is .Iaddend.loaded in shear in the zone between said bands.   
     
     
       2. A seal assembly as defined in claim 1 including a second elastomeric assembly supporting said .[.stationary.]. .Iadd.other .Iaddend.seal ring, both said first and second elastomeric assemblies including an outer band and an inner band bonded to a core of elastomeric material. 
     
     
       3. A seal assembly as defined in claim 1 wherein .Iadd.at least one of .Iaddend.said seal rings .[.are.]. .Iadd.is .Iaddend.covered, in part, by a shield of elastomeric material to protect said .[.rings.]. .Iadd.ring .Iaddend.from an abrasive pump product. 
     
     
       4. A seal assembly as defined in claim 1 wherein each .[.said.]. seal ring is constructed of a ceramic material. 
     
     
       5. A seal assembly as defined in claim 1 wherein said elastomeric assembly is provided with drive lugs cooperating with corresponding driving grooves associated with .Iadd.one of .Iaddend.said seal .[.ring.]. .Iadd.rings.Iaddend.. 
     
     
       6. A seal assembly as defined in claim 5 wherein said seal ring is provided with an elastomeric shield over a portion of its surface and said driving grooves are formed in said shield. 
     
     
       7. A cartridge-type mechanical seal comprising: a shaft sleeve adapted to be carried on the O.D. of a pump impeller shaft; a first rotatable seal ring mounted on said sleeve;   a second, stationary seal ring supportable by said sleeve during installation and adjustment thereof, said second seal ring being carried by an annular flange which is adapted to engage a stationary element; and   a setting block attached to said annular flange and having a surface engageable with said stationary element to clamp said element between said flange and said setting block.   
     
     
       8. A seal as defined in claim 7 wherein said setting block is rotatable to three positions: (1) an insertion position in which the setting block engages only said shaft sleeve; (2) an adjustment position in which the setting block engages both said shaft sleeve and said stationary element; and (3) a running position in which the setting block engages only said stationary element. 
     
     
       9. A seal as defined in claim 7 wherein said shaft sleeve is attached to the motor shaft by means of a wedge element extending through an opening in said shaft sleeve. 
     
     
       10. A seal as defined in claim 7 wherein said first seal ring is biased by means of an elastomeric assembly .[.adapted to be.]. loaded in shear. 
     
     
       11. A seal assembly as defined in claim 10 wherein said first seal ring is protected by a shield of elastomeric material over a portion of its surface. .Iadd.12. A seal assembly as defined in claim 1 wherein said one seal ring is the stationary seal ring. .Iaddend. .Iadd.13. A seal assembly as defined in claim 1 wherein the means for detachably securing the elastomeric assembly comprises a flanged extension provided on one of said bands and which is releasably secured, in a sealant manner, to said pump housing. .Iaddend.