US 2907611 A
Description (OCR text may contain errors)
Oct. 6, 1959 Y w, P, ROB|N5ON 2,907,611
SEAL PROTECTOR Filed Feb. 28, 1958 United States Patent 2,907,611 i SEAL PROTECTOR William r. Robinson, Compton, Calif., assignmto H. c. Smith Oil Tool Co., Compton, Calif., a corporation of California [Application `February zs, 195s, serial No. 718,266
4 claims. (ci. 30s-187.1)
This invention relates to a proteotingmeans for protecting seals and packings for bearings between vertically disposed rotary shafts and surrounding sleeves in abrasive environments. i
Explanatory of the present invention, it has. heretofore been proposed to drill water, oil, andtgas wells by an apparatus wherein the drill pipe is held stationaryv or against rotation in the well. Near the bottom of the drill pipe there is a hydraulically operable ,motor or turbine which is motivated or propelled by the circulation fluid that is pumped down the drill pipe. This motor or turbine in turn rotates a vertically disposed shaft within `the, bottom of the drill pipe and this shaft, in turn, drives or rotates the bit used to drill the well. There` are a number of advantagestto be derived from such an apparatus, an important `one of which is the ability to rotate the bit at comparatively high speeds.
` AIt is necessary to Aprovide some form of bearing between the rotating shaft and thesurrounding lower end of =thestationary drill pipe, and such a bearing should not only be well lubricated Iwith a lubricant maintained at a pressure of the circulation liuid in :the vicinity of the bearing, but the bear-ing` should be also protected agalinst ingress of abrasive particlescarriedby the circulation fluid. If packing seals are 'provided at the 4top and bottom `ofi the bearingto confine the..lubricant and prevent ingressof abrasive particles to-the bearing, these packingseals in` turn` are subject to` the abrasive particles car- Lied :by the circulation uid and consequently quickly becomeworn to such an extentas to leak and allo'w the abrasive particles to enter the bearing.
It is a primary object of the present invention to provide a means for protecting these packing seals from the abrasive particles in the circulation iluid and in this manner if the packing seals can be protected from abrasion the seals will function properly to prevent ingress of abrasive particles to the bearing and thus keep the lubricant fed to the bearing in a clean condition. In this manner, the life of the bearing may be materially prolonged.
With the foregoing and other objects in View, which will-bc made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:
Figure 1 is a vertical section through a vertically rotating shaft and through its surrounding sleeve or drill pipe illustrating a bearing between the shaft and sleeve as being protected and lubricated in accordance with the present invention; and
Fig. 2 is a partial view in vertical section showing a portion of Fig. l on an enlarged scale.
Referring to the accompanying drawing wherein similar reference characters designate similar parts throughout, indicates the lower end of a stationary or non-rotating drill pipe within which there is a vertically disposed shaft 11 which is rotated about its vertical axis by any suitable source of motive power, such as a hydraulically the bearing is hollow as indicated at with ports 16 d lCC` A 2 t driven turbine that is driven bythe circulation llud that is pumped down the drill pipe. Between the shaft 11 and the drill pipe 10 there is an -antif iction bearing illustrated as consisting of a ball thrust bearing 12 above and below -Which there are radial roller bearings 13 and 14.
f The `details of construction of the particular anti-friction bearing are unimportant insofar as the present invention is concerned and the nature of the anti-friction bearing may vary as to design to awide extent.
'.That portion of the shaft 11 which extends through arranged near its top so that the circulation fluid, after passing through the turbine may pass downwardly through the hollow shaft and be `discharged through the bit. 1T indicates a sub drill collar or it may comprise the top of the bit body itself. It is mounted on the `lower endV of the `shaft 11 so as to be forcibly rotated thereby.
As above explained, the problemy isto keep the bearing supplied with clean lubricant preferably at a pressure of the circulation luid in the vicinity of the bearing and to prevent ingress of abrasive particles from the circulation lluid into ythe bearing. To this end, an inner sleeve 18 is disposed between the hollow portion of the shaft 11 and the surrounding sleeve orcylinder provided by the stationary or non-rotatable drill pipe 10. This sleeve defines two cylindrical chambers' one-of which is indicated at 19 and the other of which is indicatedat 20. The latter chamber constitutes a reservoir for lubricant. A packing seal 21 is arranged between the hollow portion of the shaft 11 and the sleeve 18. This paclning seal is tightened such asby a nut 22 to form` a close wiping contact between the exterior of the rotating shaft 11 and the interior of the inner sleeve 18 which A second inner sleeve 23 yis threaded or otherwise se-` lower packing seal 24 provides a good rwipng Contact between the exterior of the rotary shaft 11 and `the interior of-:the sleeve 23 which is rigid with the stationary drill pipe. i The sub drill collar or bit body 17 extends upwardly around the lower end off the inner sleeve 23 to dieJ fine a chamber 26 open against the bottom of the lower seal. Both of the chambers 19 and 26 may be regarded as open-topped chambers which have downwardly extending lips 27 and 28 near their tops. Both chambers are partially filled with a heavy dense liquid that is emissible with the circulation fluid. An excellent liquid for this purpose is mercury, the mercury being indicated at 29 and 30 in the t'wo chambers.
The top of the lubricant reservoir is closed by a confining ring 31 through which there are ports 32 which conduct the pressure of the circulation fluid to the top of an annular piston 33 which is vertically movable in the reservoir 20. This annular piston may be equipped 'with suitable packing rings or the equivalent.
The pressure of the circulation fluid between the shaft 11 and the interior of drill pipe 10 is transmitted through the ports 32 to the top of the piston 33 and is transmitted by the piston to the lubricant in the reservoir 20. The lubricant is forced from the reservoir 20 into the bearing through ports 34 so that the pressure of the lubricant inthe bearing is always maintained at substantially outside pressure. Thecirculation fluid that is descending through the drill pipe 10 afterhaving passed through the turbine flows downwardly through the hollow portion 15 of the shaft after entering through the ports 16. The circulation fluid, however, is also effective on the tops of the two mercury columns 29 and 30 as the chambers which is rigid with the stationary or non-rotatable drill pipe contain thesesmercurycolumns have open tops.' The dcscendingcirculation fluid can of course enter thetop of chamber 19 and the discharged circulation uid rising on the outside of the drill pipe can enter the top of chamber 26z Any abrasive particles carried by1the.;circulation lluidtendingto settle in the-two. chambers-19l .and .26 f encounter. the tops of-jthe mercury. columns and sequentlvmaterially prolonged as. they arefkeptquite clean.- As'l the seals in turn prevent. ingress of abrasive particlestto the hearingzand/confine the lubricanrforced into.; the bearingfrom thereservoirZtl,` the. life of the bearing,3 ismaterially prolonged.
The downwardly directed lips 27 and; 28'f serve to con-fine themercury in the` chambers19fandl26 and depending:V upon the volume of'mercury inthechambers, these; lips may serve to keep lthe mercury in the chambers eventhouglithe entire structure illustrated is positioned horizontally in the course vof transporting the structure'v to and from the Well site.- i
From theyabove-described construction itfwillfbe appreciatedwhat where a bearingV isdisposed betweenV a rotatingshaftand a'surroundiugy stationary sleeve` such asffthe; stationary drill pipe 10 and thereis an abrasive' enviroment, that it is possible to protect the bearing from :wear due to abrasive particles by arranging packing sleeves above and `below the bearing which,..in turn, are protected against abrasion by mercury seals above the uppermost packingl seal and against the `bottom= of thev lowermost packing seal. f
Inthev foregoing description= the 'shaft 11' and' its associated structure has been described as-beingfverticallyv disposed dueto the fact thatthis is the normal positionl assumed by these parts in the course of ordinary well drilling;- yFrequently contracts-require theV drillingz off an oilwell to be maintained within 3 of vertical. There. are, however, numerous situations wherein slant-:hole drillingisy performed wherein theaxis of the well bore may depart from the vertical as high as 70. The presentlnvention issusceptible of being used in slant-holev drilling-'aswell asin -vertical drilling, it being merely necessary to lengthen the chambers 19 and 26 sutlciently to keep the mercury confined therein even though the axis of the device may.
beg-steeply slanted with respect to thevvertical` Various changes may be made in the details of construction withoutdeparting fromy the spirit-andscope of the invention `as defined by the appended claims.
1. In combination, a shaft rotatable within a surrounding sleeve, a bearing between the shaft and sleeve, seals above and below the bearing-means defining a chamber on top of the upper seal, means defining a chamber against the bottomofthe lowerfseal, both of said chambers having open tops and. having, mercury disposed therein againsttheseals.. i
2'. In combination, a shaft rotatable withinpasurrounding sleeve, a bearing between the shaft and sleeve, seals above' andbelow the-bearing,l means vdefining aV chamber on top of the, upper seal, means defining a chamber against the bottom of the lower seal, bothof said chambers having open tops and having mercury disposed therein against the seals, there being downwardly directedlipsiadjacentthe open tops ofiy the chambers.
3.: In combination, ashaft rotatable Within arsurrounding sleeve, vabearingbetween the shaftand sleeve, seals above and below the bearing, means defining a' chamber onttopof the-upper' seal, means dening` a` chamber against therbottornV of the lower seal, both-of said'chambers having. open. tops. and? having mercury disposed therein against the seals, a. lubricant reservoir adjacent the bearingand'in communication therewith, and meansfor transmittingl pressure externally of the reservoir to' the lubricant therein. l
4.: In combination, fashaft rotatable within a surround'- ingsleeve, a bearing between the shaft andlsleeve, seals above and below the bearing, mnsl defining a chamber on top of the upper seal, means dening a .chamber against the-bottom of the lower seal, bothv of said chambers having open tops and having mercury disposedthe'rein against .the seals, a lubricant reservoir vadjacent the bearing yand in communicationtherewith, and a balancing piston reciprocable in the reservoir for transmitting pressure to the lubricant therein.A
References Citedin the file ofthis patent UNITED STATES PATENTS SmartV July '16, v1957V