Stuffing box and packing rings for use therein

Patent metadata

Field	Value
Publication number	US-9903475-B2
Application number	US-201614996767-A
Country	US
Kind code	B2
Filing date	Jan 15, 2016
Priority date	Jan 15, 2016
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A packing ring is disclosed for sealingly engaging a movable rod member within a stuffing box having an internal cavity. In an embodiment, the packing ring includes a carrier and a sealing ring mounted to the carrier. The sealing ring is configured to sealingly engage with an outer surface of the rod when the rod is disposed within the internal cavity. The carrier includes a radially outer surface that is configured to sealingly engage with an internal surface of the stuffing box. In addition, the carrier includes a radially inner surface that is proximate to an outer surface of the rod when the rod extends through the stuffing box. Further, the carrier includes a plurality of lubrication grooves each groove extending from the radially outer surface to the radially inner surface and configured to convey a lubricant flow between the radially outer surface and the radially inner surface.

First claim

What is claimed is:

1. A stuffing box for receiving a movable rod, comprising:
a body including an internal surface defining an internal cavity;
a lubrication injection device mounted to the body and including an internal flow passage in communication with the internal cavity;
a plurality of packing rings stacked within the internal cavity, wherein each of the plurality of packing rings engages at least one adjacent packing ring within the stack and includes
a carrier comprising:
a central axis;
a first end including a first frustoconical surface;
a second end opposite the first end, the second end including a second frustoconical surface that is parallel to and axially spaced from the first frustoconical surface;
a radially outer surface that extends between the first end and the second end and engages with the internal surface of the stuffing box;
a radially inner surface that extends between the first end and the second end;
an annular mounting recess extending into the radially inner surface; and
a plurality of lubrication grooves each extending from the radially outer surface to the radially inner surface and into the first frustoconical surface, wherein the lubrication grooves are angularly spaced about the central axis, and wherein each lubrication groove is configured to receive a lubricant therein to convey the lubricant between the radially outer surface and the radially inner surface;
a first annular cavity extending axially into the first frustoconical surface such that the first frustoconical surface is separated into a radially outer portion and a radially inner portion;
wherein each of the lubrication grooves extends through the first annular cavity such that each lubrication groove includes a first portion extending into the radially outer portion of the first frustoconical surface and a second portion extending into the radially inner portion of the first frustoconical surface;
wherein the first portion and the second portion of each lubrication groove is aligned along a corresponding axis that is parallel to the first frustoconical surface; and

a sealing ring mounted within the annular mounting recess of the carrier, wherein the sealing ring is configured to sealingly engage with an outer surface of the rod when the rod extends through the internal cavity;
wherein at least one of the lubrication grooves of at least one of the packing rings is in communication with the internal flow passage of the lubrication injection device.

2. The stuffing box of claim 1 , wherein each carrier further comprises a cylindrical pocket extending axially into the first frustoconical surface at a position within the annular cavity.

3. The stuffing box of claim 2 , wherein the plurality of lubrication grooves comprises at least five lubrication grooves angularly spaced about the central axis.

4. The packing ring of claim 1 , wherein the plurality of lubrication grooves comprises at least five lubrication grooves.

5. The stuffing box of claim 4 wherein the plurality of lubrication grooves are evenly angularly spaced about the central axis.

6. The stuffing box of claim 1 wherein the radially outer surface of the carrier includes a first outer frustoconical surface, a second outer frustoconical surface, and an annular junction at the intersection of the first and second outer frustoconical surfaces; and wherein the first annular cavity comprises a base surface; and wherein the lubrication grooves are formed in the first outer frustoconical surface and are axially spaced from and do not intersect the base surface of the annular cavity.

7. The stuffing box of claim 1 wherein a first packing ring and a second packing ring of the plurality are stacked within the internal cavity such that the lubrication grooves of the carrier of the first packing ring lie in different axial planes from the lubrication grooves of the carrier of the second packing ring.

8. The stuffing box of claim 1 wherein the plurality of packing rings stacked within the internal cavity comprise a top and a bottom packing ring and wherein the carrier of at least one of the top and bottom packing ring is free of lubrication grooves.

9. The stuffing box of claim 1 further comprising a plurality of lubrication injection devices mounted to the body, and wherein each of the plurality of lubrication injection devices includes an internal flow passage in communication with the internal cavity.

10. A plurality of packing rings configured to be stacked within an internal cavity of a stuffing box body for sealingly engaging a rod that is movable with respect to the stuffing box body and that passes through the internal cavity, each packing ring comprising:
a carrier comprising:
a central axis;
a first end including a first frustoconical surface;
a second end opposite the first end and including a second frustoconical surface that is parallel to and axially spaced from the first frustoconical surface;
a radially inner surface that extends between the first end and the second end and an annular mounting recess in the radially inner surface;
a radially outer surface that extends between the first end and the second end and that includes a first outer frustoconical surface, a second outer frustoconical surface, and an annular junction at the intersection of the first and second outer frustoconical surfaces;
a first annular cavity extending axially into the first frustoconical surface such that the first frustoconical surface is separated into a radially outer portion and a radially inner portion;
a first plurality of lubrication grooves in the first frustoconical surface angularly spaced about the central axis and extending through the radially outer portion from the first outer frustoconical surface to the first annular cavity;
a second plurality of lubrication grooves in the first frustoconical surface angularly spaced about the central axis and extending through the radially inner portion from the first annular cavity to the radially inner surface; and
a sealing ring mounted within the annular mounting recess of the carrier and configured to sealingly engage the outer surface of the rod;

wherein the first and second plurality of lubrication grooves are configured to communicate lubricant from the internal surface of the stuffing box into the first annular cavity, and from the first annular cavity to the outer surface of the rod.

11. The plurality of packing rings of claim 10 wherein a first and a second packing ring of the plurality are disposed in a stack such that the first plurality of lubrication grooves of the carrier of the first packing ring lie in different axial planes from the first plurality of lubrication grooves of the carrier of the second packing ring.

12. The plurality of packing rings of claim 10 wherein, in the carrier of at least one packing ring of the plurality, each lubrication groove of the first plurality is aligned with a lubrication groove of the second plurality.

13. The plurality of packing rings of claim 10 wherein the first plurality of lubrication grooves comprises at least five lubrication grooves angularly spaced about the central axis.

14. The plurality of packing rings of claim 10 wherein the first plurality of lubrication grooves are evenly angularly spaced about the central axis.

15. The plurality of packing rings of claim 10 wherein, in at least one packing ring of the plurality, the first annular cavity comprises a base surface, and wherein the lubrication grooves of the first and second plurality of lubrication grooves are axially spaced from and do not intersect the base surface of the annular

Assignees

• Nat Oilwell Varco Lp

Inventors

• Ruffin Joshua Ryan
• Rappenecker Jeremy Michael

Classifications

• F16J15/183 Primary

  using a lantern ring · CPC title

• F04B39/041

  sealing for a reciprocating rod (sealing in general F16J) · CPC title

• F16J15/181

  for plastic packings · CPC title

• F16J15/18

  with stuffing-boxes for elastic or plastic packings · CPC title

• F16J15/182 Primary

  with lubricating, cooling or draining means · CPC title