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Stuffing box assembly and sealing assembly for use thereinRelated Patent Categories: Wells, Above Ground Apparatus, Inner Member Anchor Or Seal With Lateral PortStuffing box assembly and sealing assembly for use therein description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070175627, Stuffing box assembly and sealing assembly for use therein. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE OF RELATED APPLICATION [0001] This Application Claims Priority from Provisional Application No. 60/736,891 filed Oct. 15, 2005 for Packing Assembly For Rotary Drilling Swivels, the disclosure of which is incorporated herein by reference for all purposes BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a stuffing box and a sealing assembly for use in effecting fluid sealing between a fixed body and a rotating body and, in particular around the wash pipe of a rotary drilling swivel. [0004] 2. Description of Prior Art [0005] In the drilling of oil and gas wells, a drill bit is rotated in a borehole by means of a string of drill pipe. The drill pipe is rotated on the surface mechanically by a rotating table mounted on a drilling platform or by a hydraulic motor, commonly referred to as a top drive. As is common in such oil and gas well drilling, drilling fluid or mud is circulated through the drill pipe and the drill bit to cool the drill bit and remove the cuttings, the mud being recirculated to the surface and the cuttings removed from the drilling fluid/mud so it can be reused. [0006] The rotary drilling swivel commonly used in the drilling of oil and gas wells provides rotating support for the drill string suspended from it and a sealed passageway for circulating drilling fluids into the drill string. The drill pipe is in open-flow communication with a wash pipe, through which the drilling fluid flows, the wash pipe usually being stationary. A packing assembly forming part of the swivel rotates with the drill pipe, and is in sealing engagement with the wash pipe to prevent loss of drilling fluid out of the swivel assembly. [0007] Depending on the depth of the well and/or well conditions, drilling fluid pressures can reach several thousand psi, and at these high pressures, conventional, prior art packing assemblies used to seal between the wash pipe and the rotary head to which the drill pipe is secured have reduced life, resulting in leaking. [0008] In particular, as deeper wells are drilled at higher mud pressures, e.g., 6,000 psi, turning rates of 220 rpm and high flow rates of drilling mud, the wearing problem on the seals between the wash pipe and the rotary head to which the drill pipe is secured is exacerbated. For example, the wash pipe for a 3'' bore wash pipe may have a 3.65'' OD and rotate at 120 rpm at a maximum pressure of 3,500 psi. This calculates to PV of 398,565 psi-fpm. In contrast, when a 4'' bore wash pipe (OD=4,875''), typically used in deep, high-speed drilling, is employed at pressures of 6,000 psi and a turning rate of 220 rpm, a PV of 1,684,575 psi-fpm is reached. This PV value is typically more than four times more severe than that usually encountered in conventional drilling operations. Presently, packing materials used to seal between the wash pipe and the rotary head, under the severe conditions noted, have an expected life of from 20 hours to a maximum of several hundred hours. As is well known to those skilled in the art, once the packing fails, it is necessary to stop the drilling and replace the packing, an operation that in and of itself can take eight to ten hours. Furthermore, this is not the total downtime before drilling can be resumed. It will be appreciated that on a deepwater drill ship or rig, this amount of downtime translates to thousands of dollars and penalties. [0009] Typical prior packings now used in rotary drilling swivels are usually made from molded rubber and fabric composites and in this regard, a number of combinations of various fabrics and elastomers can be employed depending upon the operating conditions. For example, a common elastomer is Buna-n rubber and a common fabric is cotton. To these composites can be added lubricating materials such as graphite, molybdemum disulfide, PTFE resins, etc. [0010] It is becoming increasingly apparent that these typical prior art packings made from the materials described above do not have sufficient lifetime when operating under severe conditions of high mud pressures, high turning rates and high flow rates. [0011] Presently, there are materials that can be used to make packings or seals for these systems that can withstand these higher PV's, as well as the high heat loads generated at the interface of the packing or seal lip and the wash pipe surface. Thus, while more sophisticated materials such as PTFE, PTFE alloys, high temperature plastics and rigid elastomers/rubber composites can withstand these harsh operating conditions, they have disadvantages which affect their sealing ability. These materials, while they perform well initially, lose their sealing ability once the drilling is stopped and/or the mud pressure is reduced, e.g., when it is necessary to add a new joint of drill string or for some other reason encountered in the drilling operation. The reason that seals of these more sophisticated materials fail to seal under these conditions, i.e., moving from high PV's to low PV's, is because of their material make-up. Typically these materials are generally hard or rigid elastomers, plastics, etc., and generally yield under the initial stress and accordingly, lose their interference engagement with the wash pipe, such that when mud pressure is brought back up to operating conditions leakage occurs. As noted above, conventional packing materials of softer elastomers/rubber composites have sufficient elasticity to maintain a sealing force under high or low PV's, but they have poor wear characteristics. SUMMARY OF THE INVENTION [0012] In one embodiment the present invention provides a sealing assembly for use in sealing between a relatively rotatable housing and a member extending through the housing. The sealing assembly includes an annular seal ring carrier; an annular seal ring carried by the carrier, the seal ring having an annular, radially outer portion and an annular, radially inner portion; an annular seal ring spreader operatively engaged with the seal ring; an elastic biasing member operatively engaged with the seal ring spreader; and an annular follower. The spreader exerts a greater force on one of the radially inner or outer portions than the other of the radially inner or outer portions when the spreader is biased toward the seal ring. [0013] In another embodiment, the present invention provides a stuffing box or packing assembly for use in sealing between a fixed housing and a rotatable member extending into the fixed housing, the stuffing box assembly including a housing having a bore for receipt of a rotatable shaft, the housing forming a sealing assembly chamber, and a sealing assembly as described above received in the sealing assembly chamber in the housing. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is an elevational view, partly in section, showing a prior art stuffing box/sealing assembly used in a rotary drilling swivel; and [0015] FIG. 2 is a view similar to FIG. 1 showing one embodiment of the stuffing box/sealing assembly according to the present invention. [0016] FIG. 3 is a view similar to FIG. 1 showing another embodiment of the stuffing box/sealing assembly according to the present invention. DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS [0017] Referring first to FIG. 1, there is shown a wash pipe/stuffing box or packing gland assembly used in a conventional rotary drilling swivel, the stuffing box assembly including a conventional prior art sealing or packing assembly, all of which are well known to those skilled in the art. Referring then to FIG. 1, a wash pipe 6 extends through a stuffing box assembly shown generally as 8 comprising a packing gland or stuffing box housing 10 forming an annular chamber 12 in surrounding relationship to wash pipe 6. Housing 10 has a first end wall 14 having a bore 14A therethrough and a second end (partially shown) which is threaded as at 16 to receive a threaded follower 18. As seen, there is a second stuffing box assembly 8A which is substantially a mirror image of assembly 8. Positioned in the annulus in chamber 12 surrounding wash pipe 6 is an annular seal ring carrier 2 which is sealed against follower 18 by means of an O-ring 1. An annular lip type seal ring 3 carried by carrier 2 and partially nested in seal ring carrier 4 is of a type commonly referred to as a V-ring or Chevron ring and has an annular, radially inwardly extending seal lip 3A which sealingly engages wash pipe 6. Annular seal ring carrier 4 carries an second identical seal ring 3 which is also partially nested in a lantern ring or adapter 5 through which lubricant can be injected through a port 20 in the well known manner. A third, identical seal ring 3 is also carried by lantern ring 5 and is nested in an annular, axially facing groove 13 in end wall 14 of housing 10. [0018] Referring now to FIG. 2, there is shown one embodiment of the packing stuffing box/gland assembly of the present invention. The stuffing box assembly of FIG. 2, shown generally as 22, includes a housing 24 having a cylindrical side wall 25, an end wall 28 and is threaded opposite end wall 28 as at 30 to receive a threaded follower 32. Housing 24 forms a chamber 26 through which extends a wash pipe 34, an annulus being formed between the OD of wash pipe 34 and the inner cylindrical surface 36 of sidewall 25 of housing 24. Disposed in the annulus is an O-ring 38 that provides sealing between a seal ring carrier 40 and threaded retainer 32. Seal ring carrier 40 has an annular, axially and radially facing notch 42 in which is received a V-type or Chevron seal ring 44 having an annular, radially inwardly extending sealing lip 46 and an annular, radially outer portion 47 that also forms a sealing lip. Seal ring 44 is also nested in an annular adapter 45. As seen, seal ring 44 is engaged by an annular seal ring spreader 48 which is spaced radially inwardly from seal ring carrier 40. An annular wave spring 50 abuts one end of seal ring spreader 48. A second, annular wave spring 52 is separated from wave spring 50 by an annular spacer 54, wave spring 52 being engaged by a second annular spacer 56. A keeper ring 57, which can be an O-ring, holds spacer 56 in position. [0019] Adapter 45 engages a second annular, spacer 60 which in turn engages a wave spring 62 which is spaced from another wave spring 64 by annular spacer 66. Wave spring 64 in turn engages a second, annular seal ring spreader 66. A second O-ring keeper 65 holds spacer 60 in place. A second seal ring 68 is carried in an annular notch 70 of a second seal ring carrier 72, seal ring 68 having an annular, radially inwardly extending sealing lip 74 which is engaged by spreader 67 and an annular, radially outer portion 69 that also forms a sealing lip. The seal ring 68 is nested in a second annular adapter 76 which in turn is nested in end wall 28 of packing gland 24. Continue reading about Stuffing box assembly and sealing assembly for use therein... Full patent description for Stuffing box assembly and sealing assembly for use therein Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Stuffing box assembly and sealing assembly for use therein patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Stuffing box assembly and sealing assembly for use therein or other areas of interest. ### Previous Patent Application: Wellhead blowout preventer with extended ram for sealing central bore Next Patent Application: Post wellhead collar Industry Class: Wells ### FreshPatents.com Support Thank you for viewing the Stuffing box assembly and sealing assembly for use therein patent info. 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