Packless stuffing box annular seal assembly

Abstract

An improved annular seal assembly and packless stuffing box for an oil pumping unit of the type having a polished rod reciprocatingly extending therethrough and downhole to a pump located at the lower end of a borehole. The stuffing box has a main body that terminates in a tubing adaptor at the lower end thereof by which it can be mounted to the upper end of the tubing of a wellhead. The main body houses the annular seal assembly that includes a pressure set seal pack for sealingly engaging the polished rod. The polished rod reciprocatingly extends through the seal assembly and main body. The seal assembly includes paired metal annular cones which are capable of sealing under conditions present in the stuffing box. The seal assembly withstands such conditions far longer than traditional seal assemblies, thus reducing cost and downtime of the pumping unit.

1 . An annular seal assembly and stuffing box for an oil pumping unit; said seal assembly and stuffing box comprising:
 a housing body having an upper end opposed to a lower end, adaptor means at said lower end by which said housing can be mounted respective to said pumping unit; said housing body having a closure means at said upper end of said main body that forms a cap; a longitudinal passageway extending through said housing body through which said polished rod can extend;   a seal assembly having a plurality of mated, opposing hollow, annular cones, said cones facing each other base-to-base within each pair, said cone pairs being axially aligned with said polished rod and forming part of said inner surface of said seal assembly for sealingly engaging said polished rod;   whereby, said seal assembly can seal off and accommodate movement of said polished rod.   
   
   
       2 . The stuffing box and seal assembly of  claim 1  wherein said housing comprises a cylindrical tube within which said seal assembly fits. 
   
   
       3 . The stuffing box and seal assembly of  claim 1  and further including a screw cap forming the upper end of said stuffing box. 
   
   
       4 . The stuffing box and seal assembly of  claim 1  wherein said seal assembly comprises annular cones, wherein each cone has a slot cut entirely through one wall, extending vertically therethrough, from top to base. 
   
   
       5 . The stuffing box and seal assembly of  claim 1  wherein each said annular cone further comprises a plurality of slots that extend vertically from top to base, but only extend part of the thickness of the wall of the cone from the outer wall toward but not penetrating the inner wall of said cone. 
   
   
       6 . The stuffing box and seal assembly of  claim 1  wherein each said annular cone further comprises a cut down lower edge of the cone at the base thereof. 
   
   
       7 . An improved stuffing box and annular seal assembly of the type that can be connected to a tubing, and having a shaft received therethrough in a sealed manner therewithin and forms a tubing annulus therewith, comprising:
 said box comprising a hollow cylinder, having a longitudinal passageway extending therethrough through which said shaft can be received for either of rotational and reciprocating movement; wherein,   an axial passageway extends longitudinally through said seal assembly in parallel relationship respective to said longitudinal passageway of said box; a seal pack including pairwise arrangements of hollow truncated cones mounted within said seal holder for sealingly engaging said shaft.   
   
   
       8 . The stuffing box and seal assembly of  claim 7  wherein said seal pack comprises upper and lower paired annular truncated cone seal elements having a porous oiling channels located therebetween, and passageway means connecting said porous oiling channels for lubricating said seal assembly and said shaft. 
   
   
       9 . The stuffing box and seal assembly of  claim 7  wherein said shaft is reciprocatingly connected to a pumping unit, said seal assembly is arranged for radial movement within said chamber in a manner such that said longitudinal passageway can be moved in any radial direction within a plane that lays perpendicular to said shaft to thereby accommodate misalignment between a pumping unit horsehead and a vertical axis of a borehole. 
   
   
       10 . An annular seal assembly and stuffing box for an oil pumping unit; said seal assembly and stuffing box comprising:
 a housing body having an upper end opposed to a lower end, adaptor means at said lower end by which said housing can be mounted respective to said pumping unit; said housing body having a closure means at said upper end of said main body that forms a cap; a longitudinal passageway extending through said housing body through which said polished rod can extend;   a seal assembly having a plurality of mated, opposing hollow, annular cones, said cones facing each other base-to-base within each pair, said cone pairs being axially aligned with said polished rod and forming part of said inner surface of said seal assembly for sealingly engaging said polished rod;   wherein, said cones each have a plurality of slots cut vertically into the walls thereof; and,   whereby, said seal assembly can seal off and accommodate movement of said polished rod.