JPS6329073B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to rotating shaft seals, and more particularly to an annular continuous but axially variable seal for providing hydrodynamic lubrication between the seal and a rotating shaft. A system is disclosed that uses differential pressure to compress and hold the seal as it wears.

The present invention can be adapted for use with devices having tubular members supported in relative rotation by bearings contained within lubricant chambers within the annular spaces between the tubular members.

Such equipment is a drilling string.
string) and the drilling fluid is circulated downwardly through the passageway formed by the tubular member and upwardly within the annulus between the apparatus and the wellbore. One such member thus comprises a housing or case suspended from the lower end of the string, the other comprising a hollow shaft rotatably supported by the housing and suspending the bit at its lower end. A motor, such as a turbine, can be placed in the annular space between the housing and the shaft to rotate the shaft and thus the bit without the need to transmit torque from the surface to the housing through thousands of feet of drilling string. many. The passage thus comprises an annular space in which the turbine is disposed and connected by a port through the shaft to the bore of the shaft leading to the bit at its lower end. Typically, in such devices, the housing is connected at its upper end to the drill string and the shaft is rotated relative to the housing by a motor therebetween, thereby causing rotation around the tubular shaft. A supported helical blade or the like causes a decrease in the pressure of the drilling fluid as it passes through and rotates the blade. As in the case of turbo drills, the motor often comprises turbine blades on the shaft and tubular member within an annular space between the shaft and the tubular member. Drilling fluid circulated through the motor is restricted from flowing away through the bit.

Due to the drop in pressure across the turbine section and bit, there is a substantial pressure differential across the sealing means of this type of drilling rig. It is well known that rotating sealing means that separate pressures in this manner are subject to considerably more wear than sealing means that simply separate fluids of the same pressure. The problem of wear due to abrasive particles in the drilling fluid intercalating between the sealing means and the surfaces of the engaged tubular members is even more severe in this environment. Other factors in seal wear are the severe axial and radial vibrations encountered when drilling boreholes through the earth's structure.

Bearings mounted in the annulus will also be damaged by abrasive particles in the drilling fluid unless protected therefrom. Since bearing replacement requires expensive raising and lowering of the drill string, the bearing is isolated from the abrasive drilling fluid by placing the bearing within a lubricating chamber formed at least in part by a pair of sealing means in the annular space. Efforts were made to do so. However, if one or both of these sealing means also functions as a pressure isolation element, it will wear quickly and allow abrasive drilling fluid to enter the lubricant chamber.

Due to the adverse environment encountered by rotating the motor components located in well drilling operations, much of the research effort in developing downhole "Matsudo" motors for use in downhole drilling operations has focused on the conventional drilling "Matsudo" motors. Bearing and sealing moving surfaces from the abrasive action of the drilling fluid called ``sealing moving surfaces''
It concerned the protection of surfaces). The following US patents are specifically concerned with this problem. U.S. Patent No. 3659662, No. 3666333, No. 3971450, No.
No. 4019591, No. 4222445, No. 4256189 and No.
No. 4260032. These patents deal with the problem of protecting bearing surfaces or the like from drilling mounds by various schemes.

US Pat. No. 3,659,662 discloses a device intended to overcome this problem by providing a system in which a labyrinth is provided in the annular space of the shaft and housing. The shaft is provided with ports so that pressure is reduced across the labyrinth and equalized across sealing means forming a lubricant chamber containing the bearing. However, if the passages through the labyrinths are small, they tend to become blocked by particles in the drilling fluid, thereby reducing the cooling effect, and if they are large enough to pass large volumes of drilling fluid. If so, the excavation efficiency of bits will decrease. Furthermore, even if the labyrinth were replaced by a non-leakage third sealing means such as that disclosed in U.S. Pat. be.

US Pat. No. 3,666,333 incorporates a number of rather complex features to solve this problem. This patent shows an upper and lower seal system located above and below the bearing and consisting of grease and oil filled chambers to prevent well fluid from entering the bearing. A labyrinth of mating annular parts is positioned above the upper sealing system to further prevent the flow of drilling fluid from entering the rotating bearing and surface of the drilling motor under the higher pressure of the drill pipe hole.

Many devices, such as the device shown in U.S. Pat. No. 3,971,450, are subject to extrusion and deformation due to the heat and pressure generated within the well when unconfined in their assembly in well equipment. Use seals with irregular shapes. These seals deteriorate and become ineffective in protecting moving parts from the well environment.

US Pat. No. 4,222,445 uses buffer fluid to protect the lubricant chamber. However, if other important issues such as seal wear are not considered,
This system's ability to protect bearings has a short lifespan.

Many approaches to this problem simply attempt to use unreasonable forces, ie, large seal areas under high compression as shown in the bottom seal of US Pat. No. 4,019,591. This approach provides an initial seal, but due to high friction and subsequent charring of the seal, the seal surface wears and begins to leak lubricant.

U.S. Patent Nos. 3,449,021, 2,867,462 and
No. 3,831,954 deals with sloped sealing surfaces between tubular members. US Pat. No. 3,449,021 exemplifies such a seal for use between relatively rotating surfaces. However, the sealing contact surface for the rotating element, in the illustrated configuration, is along a rather narrow band that is not suitable for adaptation to the well drilling rig environment. Additionally, the harsh and inaccessible environment of wells makes it important to provide an effective sealing surface that can compensate for wear and avoid the need for early and frequent replacement. All of the above patents directed to sloped sealing surfaces use irregularly shaped or nonconfined sealing members that will deform under the conditions under which the invention is practiced. Furthermore, the seals are not compensated for wear to provide a relatively long sealing life.

The lubrication properties of hydrodynamic seals have been studied by the inventor and reported in several papers. Kalsi MSand GAFazekas, “Feasibility
Study of a Slanted “O-ring” as a High
Pressure Rotary Seal，“ASME Paper No.72
―WA/DE―14 (1972); Kalsi, MS,
“Elastohydrodynamic Lubrication of Offset
O-Ring Rotary Seal,”ASME Paper No.80
-C2/Lub-7 (1980) and University in 1975
A paper with the same title submitted to of Houston.

The art has long sought new and improved rotating shaft seals that overcome the difficulties and problems described above and provide a simple but effective seal in an abrasive fluid environment.
The present invention overcomes these difficulties and provides a desirable sealing system by introducing a continuous axially variable hydrodynamic sealing surface between the shaft and housing of a downhole motor. Such sealing systems operate effectively by pressure differential across the seal and at high temperatures. Additionally, such systems provide a means for compensating for wear on the seal so as to maintain a high integrity seal.

The present invention is directed to a rotating shaft seal that uses sealing members arranged in an annularly continuous but axially variable path between relatively rotating parts. Preferably, the seal is a slanted O-ring or multiple convolutions configuration.
The upper and lower seal contact members have surfaces that matingly engage the surfaces of the sealing members, preferably sloped surface(s) having multiple convolutions. The upper and lower seal contact members are arranged for relative movement therebetween to compress the sealing member.

The differential pressure is generated by an arrangement of tool elements that moves at least one of the seal contact members toward the other.

In this preferred embodiment, differential pressure forces act to compress the seal contacting member and cause the seal to fill the groove supporting the seal therein as the seal wears. The unsupported area is used to create a differential pressure by multiplication of ). Furthermore, a spring biasing member (spring biasing member)
member) forces the seal contact member to compress the seal during low differential pressure conditions that occur during motor startup and shutdown. This additional biasing action minimizes or prevents significant leakage of lubricant from the bearing and sealing sub during these times that would otherwise occur.

The arrangement of parts that causes the seal support groove to compress the seal under controlled pressure provides a system that is independent of the original shape of the seal being retained. Whatever its original shape, the seal is compressed within the confines of the seal contacting member and thus assumes the shape provided by such member.

Another feature of the invention is that a high pressure differential is communicated to the lubricant, the lubricant acting against one of the seal contact members to move the seal contact member toward the other contact member, thereby It involves the use of a lubricant contained within a chamber above the sealing member to compress the seal.

Still other features of the invention are positioned below the lower seal contact member and permitting the pressure of the environmental fluid to impinge on the lower seal contact member and preventing the environmental fluid from entering the sealing system. It includes a lower chamber filled with a highly viscous substance, such as grease, to impede the flow.

While the invention will be described in terms of preferred embodiments, it should be understood that the invention is not intended to be limited to those embodiments. On the contrary, it is intended to cover all changes, modifications and equivalents which may be included within the spirit of the invention as defined in the claims.

Referring to FIG. 1 of the accompanying drawings, a bearing and sealing sub-section 11 suitable for incorporation into a drill string is illustrated.
In a typical drill string assembly, the bit sub is connected at 12 to the lower end of sealing sub 11. Sub 11 is connected under the housing 13 of a motor sub, preferably a deep well motor as described and illustrated in US Pat. No. 3,966,369. Motor sub 13 may include a turbine motor, positive displacement motor or the like having an output shaft (not shown) connected to a shaft 14 rotatably positioned within housing 16 of sub 11. Usually included.

Housing 16 is shown having an annular upper sleeve 17 assembled within the housing bore and connected at its lower end to spacing sleeve 18. Bearing collar 19 is space sleeve 1
Connected to the bottom of 8. Alternating depending vertical arrays of spacing sleeves 18, 18a, 18b and 18c and bearing collars 19, 19a and 19b are positioned within the bore of housing 16 and include the main portion of sub-11. Shown to support elements.

These elements include a movable piston 21 slidably positioned on the outer surface of the shaft 14 between a spacing sleeve 18 and a wear sleeve 22. A spring 23 is arranged between the top end of the piston 21 and an annular inwardly facing shoulder 24 formed on the upper end sleeve 17. An annular recess in the inner wall of piston 21 supports an annular spring 26 for compressing an annular packing assembly 27 positioned in the annular recess of piston 21. An O-ring (not shown) on the outer wall of piston 21 sealingly engages within the bore of spacing sleeve 18.

A series of interconnected chambers and annular spaces 28 formed between housing 16 and shaft 14 are filled with lubricating oil to provide an oil bath for the bearings contained within sub 11. A radial bearing assembly 29 is shown between the wear sleeve 22 and the spacing sleeve 18 to provide concentric mounting of the shaft 14 within the housing 18 and to provide for concentric mounting of the shaft 14 within the housing 18 and to prevent the sub from the sub as caused by the hole bias acting on the sub. Adjust the lateral force acting on 11. The lower end of the wear sleeve 22 has an upwardly projecting portion 33 of the bearing collar 19.
It has an outwardly projecting annular shoulder portion 31 arranged to hold a thrust bearing 32 against it. bearing collar 19
is arranged such that its downwardly projecting portion 34 forms the top of a circumferential chamber for housing an incompressible thrust ring 36. The lower and inner wall portions of the circumferential chamber are provided by an "L" shaped annular ring member 37 which rides on top of the thrust bearing 32a. The bottom of the thrust bearing 32a is supported by the rotor shaft collar 38,
A rotor shaft collar 38 is clamped around the shaft 14 and extends into the annular space between the shaft 14 and the housing 16 so that the sub-11
The bearing 32a has a shoulder that holds the bearing 32a in its vertical position in the bearing and seal assembly.

Thrust bearings 32b and 32c are arranged in a manner similar to the arrangement described above for positioning bearing 32a in the assembly.
A lower radial bearing assembly 29a is shown between shaft 14 and housing 16. In the bearing arrangement described above, the top thrust bearing 32 is arranged to support thrust forces acting downwardly on the shaft 14 with respect to the housing 16. This will occur when the drill string is positioned over the bottom of the hole. When the drill bit rests on the bottom and the weight is on the drill string, thrust bearings 32a, 32b and 32
c supports the upward load on the shaft 14. The bearing and seal arrangement described above is shown in more detail in U.S. Pat. No. 4,086,788.

The lower shaft seal assembly, designated generally by the reference numeral 41 and which is the subject of the present invention, is illustrated and described in more detail with respect to FIGS. 2 and 3 of the accompanying drawings. Referring to FIG. 2 of the accompanying drawings, a lower shaft seal assembly 41 is shown between the shaft 14 and the housing below the radial bearing 29a. annular chamber 28 containing oil for lubricating the bearing assembly;
one is shown extending below bearing 29a and in fluid communication with the upper end of lower seal assembly 41. An annular space 35 for mounting a lower seal assembly is formed between shaft 14 and housing 16 and terminates at its upper end in an inwardly projecting shoulder 42 on housing 16. An annular abutment ring 43 is threadably received at the lower end of the housing 16 to define the lower end of the annular space 35 for enclosing the seal assembly 41 .

The lower seal support member 44 comprises an annular sleeve having an upwardly extending support portion 43;
Support member 44 is sized to be received at the lower end of annular space 35 . The lower end of the support member 44 rests on top of the abutment ring 43. A pair of annular felt seal rings 47 are vertically spaced apart on the inwardly facing wall of the support member 44 to provide a barrier to the ingress of drilling fluid to the lower end of the seal assembly 41. It is shown. The felt seal, along with a viscous material such as grease positioned thereon, prevents the ingress of such fluids from the well annulus to the annular space 3.
5 is not sufficient to prevent the transmission of pressure to the lower end. A port 48 is provided through the wall of the housing 16 to accommodate the insertion of grease into the annular space 35 and is arranged with fittings to seal the port closed when no grease is being injected. Grease is communicated to the interior of the support member 44 by ports 51 in the upwardly extending wall of the support portion 46. O-ring seal 30 is positioned within a groove on the outer wall of support member 44 between member 44 and the inner bore of housing 16. The upper surface 53 of the support portion 46 is contoured to matingly conform to the lower surface of the lower seal member 52. The sealing member 52 and the matched contour surface 53 are characterized by axial variations and are preferably sloped or multiply convoluted.
convoluted).

Referring to the upper end of the seal assembly 41, an annular spring array 57 such as a Beleville spring is shown.
springs) is the annular space 3 immediately below the shoulder 42.
It is located within 5. The bottom of spring array 57 acts downwardly against top surface 58 of upper annular support member 59 . The support member 59 has a downwardly extending annular portion 62 extending around the inner wall of the annular space and beyond the seal 52, the lower end of the annular portion 62 being unsupported thereunder and It is in communication with the fluid pressure within the annular space below or outside the housing 16 . Annular O-ring seal 63
is positioned in a groove around the outer wall of upper support member 59 to seal the lower end of section 62 from the higher differential pressure of oil in chamber 28 . A lower surface 64 is formed on the bottom side of a shoulder formed on the inner wall of upper support member 59 . Surface 64 is arranged to matingly mate with the upper surface of upper seal member 66 . Seal member 66 and surface 64 are characterized by axial variations and are preferably beveled or multi-convoluted. Thus, in this preferred embodiment, surfaces 64 and 53 are parallel and provide an annular sloped groove that accommodates lower annular seal 52 and upper annular seal 66. In the embodiment shown in FIG. 2, upper seal 66 is shown as an O-ring and lower seal 52 is illustrated as a braided layer packing. Because of the compressive effect of the seal assembly described above, the sealing material is compressed to fill the grooves defined by the upper and lower surfaces 64 and 53, respectively, and the outer wall of shaft 14 and the vertical inner wall of section 62. Thus, regardless of the particular shape of the packing or seal used in the assembly, the seal will be deformed into the shape of the groove. Additionally, the seal is constructed such that a radius 67 is formed by the inner edges of the vertical sealing surfaces of seal members 52 and 66 facing shaft 14.

Referring to FIG. 3 of the accompanying drawings, another embodiment of the seal assembly 41 is illustrated. Housing 1
6 and the shaft 14 is arranged between the upper shoulder 42 and the lower abutment ring 43 as in FIG. Lower support member 71
It also has a felt seal 47 disposed on the inner wall of the shaft 14 to engage the outer surface thereof. O-ring 30 is located on the outer wall of lower support member 71 and seals against the hole in housing 16. Grease injection port and accessories 4
8 provides for filling of the annular space 35 at the lower end of the seal assembly with viscous material. Lower support member 71 has an enlarged annular portion 72 at its upper end dimensioned to fill the space between housing 16 and shaft 14.

The vertical hole 73 is located at the upper end portion 72 of the support member 71.
formed in a radial series around the The upper surface of enlarged portion 72 has a surface 74 that matingly engages annular sealing member 76 . These surfaces are characterized by axial variations and preferably they are oblique or polyconvoluted. Upper support member 77 is positioned above seal member 76 and has a lower surface 78 for mating contact with the top of seal member 76 . A row of springs 57 is positioned between shoulder 42 and the top of upper support 77. A radial series of vertical holes 79 are also formed in the upper support 77 and are aligned with the vertical holes 73 in the upper portion 72 of the lower support member 71. The top portion of hole 79 is enlarged to receive the head 81 of pin 82 which is sized to be received within aligned holes 79 and 73. A vertical passage 83 connects the annular space 35 in the lower portion of the seal assembly to the bottom of each hole 73. The oil is on the upper support 77
The chamber or space 28 above is filled. FIG. 4 of the accompanying drawings shows a top view of the upper support 77. Head 81 of pin 82 is illustrated in an assembled position within the radial series of vertical holes 79.

Seals 76 are connected to upper and lower support members 7, respectively.
a suitable sealing material arranged in a continuous annular shape, preferably with inclined or multi-convoluted axial variations, to fit within the grooves defined by surfaces 78 and 74 on 7 and 71; Consists of layers. Radiation 86 is formed on the top and bottom inwardly facing edges of the seal 76 to accommodate lifting of such inwardly facing edges of the seal by the hydrodynamic forces of the lubricating oil moving past the seal.

The hydrodynamic effect of the lubricant film on the seal will become more apparent with reference to FIG. 5 of the accompanying drawings.
Figure 5 shows the shaft 1 during one rotation of the shaft 14.
4 is a schematic representation of the circumferentially developed path of the seal 76 of FIG. 3 moving with respect to FIG. Because of the axial variations in the seal, such as the sloped shape of the seal 76 relative to the path of rotation of the shaft surface 14, the seal having a vertical width S moves through a path having a vertical width P during one rotation of the shaft 14. do. As the shaft rotates relative to the seal, the lubricant tends to move substantially horizontally around the shaft. The horizontal velocity applied to the oil is represented by line V _O in FIG. V _O
The velocity expressed by is divided into two vector components: V _L , which is the velocity that moves the oil laterally along the path of the seal, and V _T , which is the velocity that acts across the sidewall of the seal 76. be able to. Component V _T is the roundness 86 at the edge of the seal 76
causes the oil to lift the seal and flow under the seal, thereby seal 7
6 and the shaft 14. Additionally, because there is a pressure differential across the seal 76 due to the pressure generated across the downhole motor, there is a net downward force on the oil moving back and forth across the seal, for example as the shaft moves relative to the seal. be. The back and forth movement of the oil is due to the undulated or sinusoidal path taken by the seal relative to the shaft, which has the effect of positioning parts of the shaft alternately above and below the seal. This sealing system and the effect of the hydrodynamic flow generated on it are:
Continuously seal lubricated surfaces which tend to reduce the temperature of the seal and lubricate the rotating shaft 7
6 and the shaft 14, thus preventing the seal from schorchiping and becoming brittle. Prevention of charring and embrittlement greatly reduces wear on the seals. The net flow of oil in one direction also aids in the temperature reduction function of the system by carrying heat away from the sealing surfaces.

When a drilling rig having a seal assembly according to the invention described above is operated, a pressure differential is created across the rig such that higher pressure exists in the area of the rig above the drill bit than below the drill bit. . The higher pressure in this device is transmitted to the upper end of bearing and sealing sub 11 (FIG. 1) by piston 21 at the upper end of sub 11. This pressure is carried throughout sub 11 by lubricating oil in chamber 28 to the lower end of sub bodering seal assembly 41. Referring to FIG. 2, this pressure is directed to the upper end of upper support member 59 and acts downwardly across area _A1 . This downward force is directed to the top surfaces of seals 52 and 66. Bottom support member 44 is held against downward movement by abutment ring 43, thus compressing the seal between upper and lower support members 59 and 44, respectively. As the inwardly facing surfaces of seals 52 and 66 wear, the predictable forces between the support members suitably close the grooves defined by surfaces 53 and 64, continually constraining the seals as they wear. Hold and press the seal into sealing engagement with the shaft and upper support member.

The differential pressure mentioned above, which acts to force the supporting members together, is
The shape of the upper and lower seal supports and their cooperative relationship in the assembly
This is further enhanced by the unbalanced area effect resulting from the relationship. As mentioned above, the downward force on the top of the seal is represented by the higher pressure P _H in the device bore acting across area A ₁ as shown in FIG. The downward pressure is the product of A ₁ ×P _H .
The lower well annulus pressure P _L acts across area A ₂ on unsupported portion 62 depending from support member 59 . The force due to the fluid pressure acting upwardly on the upper support member 59 in this manner is P _L ×A ₂ . The third upward force acting on the support member 59 is A ₁ -
It is represented by an unknown pressure P _S acting across the seal or area A ₃ also represented by A ₂ .
A simple force diagram can be drawn using pressure and area examples to show that the pressure P _S acting across the seal is always greater than the pressure of the lubricant in the upper chamber 28. pressure across seal
P _S is calculated as P _S =(P _H ·A ₁ −P ₁ ·A ₂ )/(A ₁ −A ₂ ). The effect of this unsupported area thereby enhances the wear compensation characteristics of the system.
Not only will the seal last longer, but uncontrolled oil leakage past the seal at a rate greater than the desired leak rate is prevented.

The portion of the seal assembly below seals 66 and 52 is filled with a highly viscous material, such as grease, which cooperates with felt seal 47 to prevent drilling fluid from advancing into the seal area. The felt seal 47 is also impregnated with grease. The grease under the seal, together with the net downward flow of oil as described above, prevents drilling fluid from entering the assembly from below. however,
The system allows the pressure of the drilling fluid in the well annulus to be transferred to the grease chamber below seals 66 and 52.

When the apparatus of FIG. 1 is in place and its rotation is started or stopped, the pressure differential relied upon to compress the seal is sufficient to be operative to prevent leakage of lubricant past the seal. It's not expensive. Spring array 57 thus acts downwardly against upper support member 59 during periods of little or no rotation in addition to holding the components in the assembly.

In the embodiment shown in FIG.
multiplying effect of the pressure difference across
It operates similarly to the embodiment of FIG. 2, as described above, except that it represents an unsupported area that provides an .

The foregoing description of the invention has been directed primarily to certain preferred embodiments in accordance with the requirements of patent law for purposes of explanation and illustration. It will be apparent, however, that many modifications and changes may be made in the specifically described and illustrated apparatus and methods without departing from the scope and spirit of the invention. For example, although the system disclosure has been described primarily with respect to an angled seal member, seal members having shapes with sufficient axial variation, e.g., multiple ocnvolutions, are illustrated to produce the desired hydrodynamic lubrication. Alternatives to the angled seals of the described embodiments may be apparent from the description and illustrations herein. Additionally, various changes in size, shape and materials and details of the illustrated embodiments will be apparent to those skilled in the art without departing from the invention in its broadest aspects.
Finally, although this sealing device has been described for use in drilling equipment, it is suitable for use in any equipment that uses rotating seals. Therefore, the invention is not limited to the particular forms of construction illustrated and described, but includes all modifications that may come within the scope of the claims.

It is Applicant's intention in the appended claims to cover such modifications and variations as fall within the true spirit and scope of the invention.

[Brief explanation of drawings]

FIG. 1 shows a partial vertical cross-sectional view of well equipment for use in a downhole drilling system that may incorporate a lower shaft seal in accordance with the present invention. FIG. 2 is a detailed vertical cross-sectional view of the lower shaft seal area of FIG. 1 containing a rotating shaft seal in accordance with the present invention. 3 is a vertical cross-sectional view of a portion of the lower shaft seal area of FIG. 1 including another embodiment of a rotary shaft seal according to the present invention; FIG. 4 is a partial top view of the upper support member of FIG. 3; FIG. FIG. 5 is a diagram of an offset O-ring seal with a corresponding velocity diagram. In the figure, 11... Bearing and sealing sub-area, 14... Shaft, 16... Housing of sub-11, 18, 18a, 18b, 18c... Spacing sleeve, 19, 19a, 19b... Bearing collar, 21... Movable piston, 29a... Radial bearing, 28...Annular chamber, 35...
Annular space, 41...lower shaft seal assembly, 4
2... Shoulder, 43... Annular abutment ring, 44... Lower seal support member, 47... Annular felt seal ring, 52... Lower seal member, 57... Spring row, 5
9... Upper annular support member, 62... Annular portion extending downward, 63... Annular O-ring seal, 66
...Upper seal member, 71...Lower support member, 76...
Annular sealing member 77... Upper support member.

Claims (1)

Claims: 1. A rotating shaft seal system for sealing an annular space between a rotating shaft and its housing, the system comprising: an annular sealing means having upper and lower engagement surfaces; an annular sealing means having an axially variable shape about the rotating shaft such that one sealing surface of the sealing means slidably engages the rotating shaft; and upper and lower engaging surfaces of the sealing means; first and second means for interlockingly engaging;
first and second means arranged to permit relative longitudinal movement relative to each other; and actuated by differential fluid pressure to bias the first and second engagement means toward each other. and means for substantially preventing contact of the sealing means with the fluid in the environment of the housing. 2. The rotary seal system of claim 1, wherein said means for substantially preventing contact comprises a chamber containing a lubricating fluid in which said sealing means is positioned. 3. The rotary seal system of claim 2, wherein the sealing means separates the chamber into a high pressure side and a low pressure side and a positive flow of lubricating fluid is maintained across the sealing means. 4. The sealing means is in fluid communication on the high pressure side with a first chamber containing a lubricating fluid and a second chamber containing a fluid having a greater viscosity than the lubricating fluid.
The rotary seal system of claim 1 in fluid communication with the chamber on the low pressure side and wherein a positive flow of lubricating fluid is maintained across the sealing means. 5. The rotary seal system of claim 4 further comprising means for communicating the pressure of an environment within the interior of the shaft to the fluid in one of the chambers. 6. The rotary seal system of claim 4 further comprising means for communicating environmental pressure outside the housing to the fluid in one of the chambers. 7 further comprising barrier means between the fluid in the chamber and the fluid in the environment of the housing and shaft, the barrier means being capable of providing pressure communication but preventing fluid communication in the environment to the chamber; 5. The rotary seal system according to claim 4, which is capable of substantially preventing. 8 one of the first and second engagement means is vertically movable between the housing and the shaft and adapted to matingly engage one of the top and bottom surfaces of the sealing means; an annular ring means having arranged portions, the annular ring means comprising:
forming an unsupported area and biasing the portion of the annular ring means into mating engagement with one of the top and bottom surfaces of the sealing means; A sealing system according to claim 1, having one of its top and bottom surfaces for enforcing an annular ring. 9 further comprising an oil-filled chamber adjacent to and in fluid communication with the sealing means, the annular ring being positioned between the chamber and the sealing means, and a drill string; 9. The seal system of claim 8, further comprising means for transmitting the pressure of the drilling fluid within the oil-filled chamber. 10 an annular barrier means interposed between the housing and the shaft and vertically spaced from the other of the top and bottom surfaces and the bottom of the housing; 10. The seal system of claim 9 further comprising a viscous fluid in the longitudinal space between the top and bottom surfaces. 11. The sealing system of claim 1 further comprising a radius formed on at least one edge of the flat sealing surface.