A TELEMETRY TOOL JOINT

Abstract

A telemetry tool joint may comprise a tool joint body adapted for connection to a downhole tubular as part of a tool string. The tubular may be a drill pipe or a downhole tool such as a drill bit or component of a bottom hole assembly. The tool joint body may comprise an axial bore comprising a bore wall having an interior wall surface and a tapered outer wall surface. The tapered outer bore wall surface may comprise a first continuous thread form having multiple turns comprising a first thread start and a first thread end and a second continuous thread form having multiple turns comprising a second thread start and a second thread end. The respective thread forms may be separated by a gap along the tapered outer bore wall surface. The gap may comprise one or more annular recesses adapted for housing a radially oriented inductive coupler.

Claims

1. A telemetry tool joint, comprising: a tool joint body adapted for connection to a downhole tubular; the tool joint body comprising an axial bore comprising a bore wall; the bore wall comprising an inner bore wall surface and an outer bore wall surface; at least a portion of the outer bore wall surface comprising a conical surface; the outer bore wall conical surface further comprising a first continuous thread form having multiple turns comprising a first thread start and a first thread end and a second continuous thread form having multiple turns comprising a second thread start and a second thread end; the first continuous thread form being separated from the second continuous thread form by a gap along the outer bore wall conical surface, wherein the gap comprises an annular recess formed in the outer bore wall conical surface adapted for housing a radially oriented transmission device.

2. The telemetry tool joint of claim 1, wherein the tool joint body comprises a pin end or a box end tool joint.

3. The telemetry tool joint of claim 1, wherein the downhole tubular comprises an upset drill pipe.

4. The telemetry tool joint of claim 1, wherein the downhole tubular comprises a downhole tool adapted for use in a bottom hole assembly.

5. The telemetry tool joint of claim 1, wherein the tool joint body comprises a drill bit.

6. The telemetry tool joint of claim 1, wherein the tool joint body further comprises a weld surface comprising a shoulder weld surface joining a conical weld surface adapted for connection to the downhole tubular.

7. The telemetry tool joint of claim 1, wherein the first and second thread forms comprise a helical thread form.

8. The telemetry tool joint of claim 1, wherein the first and second thread forms comprise a straight thread form.

9. The telemetry tool joint of claim 1, wherein the first thread form varies from the second thread form.

10. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises a flexible ring.

11. The telemetry tool joint of claim 1, wherein the annular recess comprises one or more bumper seats.

12. The telemetry tool joint of claim 1, wherein the annular recess comprises an annular bumper seat.

13. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises a mesh housing.

14. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises a mesh housing comprising one or more bumpers.

15. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises a mesh housing comprising an annular bumper.

16. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises an MCEI core comprising at least one embedded electrical conductor within the core.

17. The telemetry tool joint of claim 1, wherein the radially oriented transmission device comprises MCEI core segments strung onto an electrical conductor.

18. The telemetry tool joint of claim 1, wherein the gap comprises a hardened outer bore wall annular surface intermediate the first and second thread forms.

19. The telemetry tool joint of claim 1, wherein the annular recess comprises hardened bottom and side surfaces.

20. The telemetry tool joint of claim 1, wherein the gap comprises two or more annular recesses.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a diagram of a side view section of a tool joint assembly of the present invention.

[0033] FIG. 2 is a side view diagram of a pin end tool joint of the present invention.

[0034] FIG. 3 is a diagram of a side section of a box end tool joint of the present invention.

[0035] FIG. 4 is a perspective diagram of a cross-section of a transmission device of the present invention.

[0036] (PRIOR ART) FIG. 5 is a cross-sectional diagram of an embodiment of a downhole tool string.

[0037] (PRIOR ART) FIG. 6 is a perspective diagram of an embodiment of an inductive resistivity tool.

[0038] (PRIOR ART) FIG. 7 is a cross-sectional diagram of an embodiment of a transceiver in an inductive resistivity tool.

[0039] (PRIOR ART) FIG. 8 is a perspective diagram of an embodiment of a coil disposed in an embodiment of a flexible ring.

[0040] (PRIOR ART) FIG. 9 is a diagram of power verses frequency in a bare wire and in a ferrite shielded wire.

[0041] (PRIOR ART) FIG. 10 is a perspective diagram of another embodiment of a coil disposed in another embodiment of a flexible ring.

[0042] (PRIOR ART) FIG. 11 is a cross-sectional diagram an embodiment of a coil disposed in an embodiment of an annular recess.

[0043] (PRIOR ART) FIG. 12 is a cross-sectional diagram another embodiment of a coil disposed in an embodiment of an annular recess.

[0044] (PRIOR ART) FIG. 13 is a cross-sectional diagram another embodiment of a coil disposed in an embodiment of an annular recess.

[0045] (PRIOR ART) FIG. 14 is a cross-sectional diagram another embodiment of a coil disposed in an embodiment of an annular recess.

[0046] (PRIOR ART) FIG. 15 is a cross-sectional diagram another embodiment of a coil disposed in an embodiment of an annular recess.

[0047] (PRIOR ART) FIG. 16 is a cross-sectional diagram another embodiment of a coil disposed in an embodiment of an annular recess.

[0048] (PRIOR ART) FIG. 17 is a perspective diagram of an embodiment of a flexible ring.

[0049] (PRIOR ART) FIG. 18 is a perspective diagram of another embodiment of a flexible ring.

[0050] (PRIOR ART) FIG. 19 is a perspective diagram of another embodiment of a flexible ring.

[0051] (PRIOR ART) FIG. 20 is a perspective diagram of another embodiment of a flexible ring.

[0052] (Prior Art) FIG. 21 is diagram of a mesh housing of the present invention.

[0053] (Prior Art) FIG. 22 is a cross-section diagram of a transmission device of the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

[0054] Referring to FIGS. 1-4, this application presents an alteration and modification of U.S. Pat. No. 7,265,649, to Hall et al., entitled Flexible Inductive Resistivity Device, issued Sep. 4, 2007, incorporated herein by this reference. Also, U.S. patent application Ser. No. 17/893,575, to Fox, entitled A Downhole Electromagnetic Core Assembly, filed Aug. 23, 2022, is incorporated herein by this reference. The teachings of said references are applicable to the present disclosure in so far as they are not modified by the present disclosure. Prior Art FIGS. 21, 22 are taken from FIGS. 3, 4 of the '575 reference.

[0055] The present disclosure presents a telemetry tool joint 600 that may comprise a threaded portion and a weld surface. The tool joint 600 may comprise a tool joint body 720 of a pin end or a box end that may be adapted for connection by means of welding to a downhole tubular such as a drill pipe, heavy weight drill pipe, drill collar, drill bit, or other downhole tool found in the bottom hole assembly of a downhole tool string. The tool joint body 720 may comprise a pin end 610 or a box end 605 tool joint having an axial bore 615 comprising a bore wall 650 for the pin end and 655 for the box end. The axial bore 615 may comprise an inner bore wall surface 660 and an outer bore wall surface 680/685 for the pin and box ends, respectively. At least a portion of the outer bore wall surface 680/685 may comprise a conical weld surface 730 and a shoulder weld surface 735. The respective weld surfaces may be attached to matching surfaces on the upset ends of a downhole tool such as a drill pipe or the thickened ends of any other downhole tool.

[0056] The outer bore wall 680/685 may further comprise a first continuous thread form 645A for the pin end and 635A for the box end adapted for connection in a tool sting. The respective thread forms may have multiple thread turns comprising a first thread start 690A for the pin end and 695A for the box end and a first thread end 690B/695B for the pin and box ends, respectively. A second continuous thread form 645B for the pin end and 635B for the box end having multiple turns may comprise a second thread start 690C for the pin end and 695C for the box end respectively and a second thread ends 690D/695D.

[0057] The first continuous thread form 645A/635A may be separated from the second continuous thread form 645B/635B by a gap 640 along the outer bore wall surface of the pin 680 and box 685. The gap may be one or more threads wide as measured crest to crest of adjacent threads. The gap 640 may comprise one or more annular recesses 630A/630B formed in the outer bore wall surface 680/685. The annular recesses may be adapted for housing a radially oriented transmission device or inductive coupler 620. The orientation of the transmission device may direct an electromagnetic signal between interconnected pin and box end tool joints.

[0058] The telemetry tool may comprise first 645A/635A and second 645B/635B thread forms comprising a helical thread form. The respective first 645A/635A and second 645B/635B thread forms may comprise a straight thread form. The first thread form 645A/635A may vary from the second thread form 645B/635B. The variations may include thread diameter, pitch, coarseness, hardness, height, gage, thickness, form, or the like.

[0059] The radially oriented transmission device 620 may comprise a rigid or flexible ring comprising a magnetically conductive electrically insulating, MCEI, core 725. And an electrical conductor embedded therein. See (Prior Art) FIG. 22.

[0060] The radially oriented transmission device 620 may comprise a mesh housing 700 around its non-transmitting core surfaces. The mesh housing 700 may comprise one or more bumpers 705. The bumpers may comprise a metal on non-metal, such as a polymer suitable for use in the harsh downhole environment. Alternatively, the mesh housing 700 may comprise an annular bumper 705. The respective bumpers may be disposed along the interior or exterior of the mesh housing or along both sides of the housing. To accommodate the presence of the bumpers, the annular recess 630A/630B may comprise one or more bumper seats. Examples of such bumper seats may be depicted in (Prior Art) FIG. 22.

[0061] The radially oriented transmission device 620 may comprise an MCEI core 725 comprising at least one embedded electrical conductor 625 within the core 725. The device 620 may further comprise a top transmission surface 710 comprising a depression 715. The depression 715 may be disposed on the top surface of the core above the electrical conductor. The MCEI core 725 may be a solid ring or it may comprise ring segments. The ring segments may be strung along the electrical conductor and held in place by the mesh housing.

[0062] The gap 640 may comprise a hardened outer bore wall 680/685 annular surface intermediate the first 645A/635A and second 645B/635B thread forms. The hardened surface may be harder than the surrounding bore wall. The gap 640 may comprise hardened bottom and side surfaces. The hardened surfaces may be achieved by brinelling, shot or laser peening, plating, heat treating, or chemical treating the desired surfaces.

[0063] The remainder of the detailed description is taken from the '649 reference and is applicable to the teachings of FIGS. 1-4, except as modified by said figures.

[0064] Referring now to (PRIOR ART) FIG. 5, a downhole tool string 31 may be suspended by a derrick 32. The tool string may comprise one or more downhole components 36, linked together in a tool string 31 and in communication with surface equipment 33 through a downhole network. Having a network in the tool string 31 may enable high-speed communication between each device connected to it and facilitate the transmission and receipt of data between sensors, energy sources, and energy receivers.

[0065] The tool string 31 or surface equipment 33 may comprise an energy source or multiple energy sources. The energy source may transmit electrical current to one or more downhole components 36 on the bottom hole assembly 37 or along the tool string 31. In some embodiments of the invention, one or more downhole component 36 may comprise sensors. These sensors may sense gamma rays, radioactive energy, resistivity, torque, pressure, or other drilling dynamics measurements or combinations thereof from the formation being drilled. Any combination of downhole components 36 in a tool string 31 may be compatible with the present invention. In some embodiments of the invention the drill string 31 may comprise an energy source that is radioactive or emits subatomic particles, such as gamma ray or neutron sources. The neutron source may comprise an Americium Beryllium source or it may comprise a pulsed neutron generator which uses deuterium and/or tritium ions. Data may be transmitted up and down the tool string 31 and between different tool components 36.

[0066] Data may be transmitted along the tool string 31 through techniques known in the art. A preferred method of downhole data transmission using inductive couplers disposed in tool joints is disclosed in the U.S. Pat. No. 6,670,880 to Hall, et al, which is herein incorporated by reference for all it discloses. An alternate data transmission path may comprise direct electrical contacts in tool joints such as in the system disclosed in U.S. Pat. No. 6,688,396 to Floerke, et al., which is herein incorporated by reference for all that it discloses. Another data transmission system that may also be adapted for use with the present invention is disclosed in U.S. Pat. No. 6,641,434 to Boyle, et al., which is also herein incorporated by reference for all that it discloses. In some embodiments, of the present invention alternative forms of telemetry may be used to communicate with the downhole components 36, such as telemetry systems that communicate through the drilling mud or through the earth. Such telemetry systems may use electromagnetic or acoustic waves. The alternative forms of telemetry may be the primary telemetry system for communication with the tool string 31 or they may be back-up systems designed to maintain some communication if the primary telemetry system fails.

[0067] A data swivel 34 or a wireless top-hole data connection may facilitate the transfer of data between components 36 of the rotatable tool string 31 and the stationary surface equipment 33.

[0068] Downhole tool string components 36 may comprise drill pipes, jars, shock absorbers, mud hammers, air hammers, mud motors, turbines, reamers, under-reamers, fishing tools, steering elements, MWD tools, LWD tools, seismic sources, seismic receivers, pumps, perforators, packers, other tools with an explosive charge, mud-pulse sirens. Downhole LWD Tools may be in the bottom hole assembly 37 or along the length of the downhole tool string 31. The tools may be inductive resistivity tools 35, sensors, drill bits, motors, hammers, steering elements, links, jars, seismic sources, seismic receivers, sensors, and other tools that aid in the operations of the downhole tool string 31. Different sensors are useful downhole such as pressure sensors, temperature sensors, inclinometers, thermocouplers, accelerometers, and imaging devices.

[0069] Preferably the downhole tool string 31 is a drill string. In other embodiments the downhole tool string 31 is part of a production well. In the present embodiment, an embodiment of a resistivity tool 35 in accordance with the present invention is shown producing a magnetic field 30 and projecting the magnetic field 30 through the formation 40. In addition to a resistivity tool 35, the tool string 31 may comprise an acoustic sensor system, hydrophone system, an annular pressure sensor system, formation pressure sensor system, a gamma ray sensor system, density neutron sensor system, a geophone array system, or an accelerometer system, directional drilling system, an inclination sensor system that may include a gyroscopic device, a drilling dynamics system, another system that may be used to evaluate formation properties, an active sensor, a passive sensor, or combinations thereof.

[0070] Control equipment may be in communication with the downhole tool string components 36 through an electrically conductive medium. For example, a coaxial cable, wire, twisted pair of wires or combinations thereof may travel from the surface to at least one downhole tool string component. The medium may be in inductive or electrical communication with each other through couplers positioned to allow signal transmission across the connection of the downhole component and the tool string. The couplers may be disposed within recesses in either a primary or secondary shoulder of the connection or they may be disposed within inserts positioned within the bores of the drill bit assembly and the downhole tool string component. As the control equipment receives information indicating specific formation qualities, the control equipment may then change drilling parameters according to the data received to optimize drilling efficiency. Operation of the drill string 31 may include the ability to steer the direction of drilling based on the data.

[0071] Referring now to (PRIOR ART) FIG. 6 an embodiment of an inductive resistivity tool 201 is shown as part of a downhole drill string 31. The resistivity tool 201 is shown intermediate first and second tool joints 202, 203. A magnetic field 30 is shown being produced by two transmitting transceivers 204 and being received by three receiving transceivers 205. The magnetic field 30 is induced into the formation, which then in turn induces the receivers 205. By projecting the magnetic field through the formation and comparing the strength of the received signal to that of the transmitted signal, the resistivity of the formation may be determined. Because high resistivity is believed to have a direct correlation with a high concentration of hydrocarbon and/or petroleum products in the formation, resistivity measurements may be used to determine the petroleum potential of a formation during the drilling process. A sleeve 206 may be disposed around the components of the resistivity tool 201 to protect them from mud and/or debris. Although specific numbers of receiving and transmitting transceivers 205, 204 have been shown in the present embodiment, any combination of any number of receiving and transmitting transceivers 205, 204 may be consistent with the present invention.

[0072] Referring now to (PRIOR ART) FIG. 7, a cross sectional view of an embodiment of a portion of a resistivity tool 201 is shown without a sleeve 206. A central bore 301 is disclosed through which drilling mud may be transferred. The central bore 301 is formed within a tubular wall comprising an inner diameter 302 and an outer diameter 303. An annular radial recess 304 is shown formed in the outer diameter 303. A coil 305 is placed within the radial recess 304 and may act as a transceiver to project induction signals outward from the resistivity tool 201.

[0073] Referring now to (PRIOR ART) FIG. 8, an enlarged embodiment of a coil 305 is shown disposed in a radial recess 304. Although in the present embodiment of the invention five turns of coil 305 are shown, any number of turns of coil 305 may be compatible with the invention. An embodiment of a flexible ring of magnetically conducting material 401 is shown disposed intermediate the coil 305 and a surface 408 of the radial recess 304. As electrical current is passed through the coil 305 a magnetic field or induction signal may be generated. The placement around the coil 305 of magnetically conducting material, or in other words, material with a high magnetic permeability, is believed to filter the range of frequencies of the induction signal. Ferrite is a compound known to have a high magnetic permeability. Unfortunately, ferrite is also known to be quite brittle and susceptible to cracking and breaking. This may be especially true in the extreme temperature and pressure conditions that exist in downhole environments. Cracks in the magnetically conducting material that are normal to the direction of travel of the magnetic field of coil are believed to be most disruptive to the projection of an inductive signal.

[0074] In order to take advantage of the high magnetic permeability of ferrite while reducing the risk of cracking the brittle material, a flexible assembly of ferrite segments is formed in the shape of a ring. Flexible rings 401 may be advantageous for ease of production and assembly of the resistivity toot In the present embodiment of the invention, the flexible ring 401 comprises a plurality of ferrite segments 402 that are flexibly joined together with a flexible adhesive backing 407. Although in this embodiment a flexible adhesive backing 407 is shown, other embodiments of flexible backing are encompassed within the claims of this application. Additionally, adjacent ferrite segments 402 may be connected by an adhesive, moldings, form, brace, hinge, tie, string, tape, or combinations thereof.

[0075] In the present embodiment a flexible ring 401 is shown comprising a generally circular trough. The circular trough comprises a bottom end 403, two sides 404 and an open end defined by a plane 405 comprising a distal end of each of the sides. In some embodiments of the invention the plane 405 of the open end may be generally parallel to a longitudinal surface 406 of the inner diameter 302 of the tubular wall, see (PRIOR ART) FIG. 7. In other embodiments the plane 405 of the open end forms an angle of between 1 and 89 degrees with a longitudinal surface of the inner diameter of the tubular wall. In some embodiments of the invention the radial recess 304 may comprise at least two flexible rings tilted at different angles. Although in the present embodiment a generally circular trough is shown, embodiments of the invention may comprise a flexible ring with a generally circular trough geometry, a generally cylindrical geometry, a dual trough geometry, or combinations thereof. The flexible ring may comprise a material selected from the group consisting of soft iron, ferrite, a nickel alloy, a silicon iron alloy, a cobalt iron alloy, a mu-metal, a laminated mu-metal, barium, strontium, carbonate, samarium, cobalt, neodymium, boron, a metal oxide, ceramics, cermets, ceramic composites, rare earth metals, an aerogel composite, polymers, organic materials, thermoset polymers, vinyl, a synthetic binder, thermoplastic polymers, an epoxy, natural rubber, fiberglass, carbon fiber composite, polyurethane, silicon, a fluorinated polymer, grease, epoxy, polytetrafluoroethylene, a perfluoroalkoxy compound, resin, potting material, and combinations thereof. The magnetically conductive material may comprise a relative magnetic permeability range of between 100 and 20000. In some embodiments of the invention the magnetically conductive material may comprise ferrite in the form of fibers, strips, shavings, powder, crystals, or combinations thereof.

[0076] Referring now to (PRIOR ART) FIG. 9, an embodiment of a plot 501 of signal frequency 502 verses power 503 is shown for a ferrite shielded wire 504 compared to a non-shielded wire 505. The plot of the non-shielded wire 505 shows elevated power 503 for a broad range of frequencies 502. The plot of the ferrite shielded wire 504 shows an elevated power 503 for a narrower range of frequencies 502, and higher maximum power 503 than the bare wire. This property of electromagnetic signals in wire shielded by ferrite or by other magnetically conducting materials is believed to sacrifice frequency range for a higher power intensity, or stronger signal. Strong signals may be important for transmission and receiving signals in downhole environments.

[0077] Referring now to (PRIOR ART) FIG. 10, another embodiment of a flexible ring of magnetically conductive material 401 is shown disposed around three coil turns. The flexible ring 401 is disposed within the radial recess 304 and comprises one continuous and flexible piece of magnetically conductive material. The trough comprises magnetically conductive fibers and/or powders in conjunction with a matrix material to give flexibility to the magnetically conductive material. U.S. Pat. No. 4,278,556 to Tada, which is herein incorporated by reference for all that it contains, discloses a procedure for producing flexible magnets, including pulverizing ferrite particles for use in the production of flexible magnets. U.S. Pat. No. 6,259,030 to Tanigawa et al., U.S. Pat. No. 6,915,701 to Tarler, U.S. Pat. No. 6,849,195 to Basheer et al., U.S. Pat. No. 4,881,988 to Bonser, and US Publication No. 2006/0208383 to Aisenbrey, all of which are herein incorporated by reference for all that they contain, disclose methods of producing and/or examples of flexible magnets adaptable for use in electromagnetic applications. Magnetic particles may be compatible with the present invention, including, ferrite in the form of fibers, strips, shavings, powder, crystals, or combinations thereof. A continuous piece of flexible magnetically conductive material may be less susceptible to cracking or breakage from downhole stresses, as well as during production and assembly of the induction toot In some embodiments of the invention the flexible ring may comprise two or more flexibly attached segments. These flexibly attached segments may be adapted to allow the flexible ring to open and close. This may be especially useful during the process of assembling the resistivity tool.

[0078] (Prior Art) FIGS. 11-16 are all cross sectional diagrams of embodiments of coils 305 disposed in various arrangements within the radial recess 304. (PRIOR ART) FIG. 11 discloses two coil turns near an open end 701 of a radial recess 304. A flexible ring of magnetically conductive material 401 is disposed under the coil 305 and comprises a generally cylindrical geometry. Open space between the turns of the coil 305 and the radial recess 304 may be filled with a potting material 702. The potting material may comprise a material selected from the group consisting of polymers, organic materials, thermoset polymers, vinyl, an aerogel composite, a synthetic binder, thermoplastic polymers, an epoxy, natural rubber, fiberglass, carbon fiber composite, polyurethane, silicon, a fluorinated polymer, grease, polytetrafluoroethylene, a perfluororoalkoxy compound, resin, soft iron, ferrite, a nickel alloy, a silicon iron alloy, a cobalt iron alloy, a mu-metal, a laminated mu-metal, barium, strontium, carbonate, samarium, cobalt, neodymium, boron, a metal oxide, ceramics, cermets, ceramic composites, rare earth metals, and combinations thereof.

[0079] (PRIOR ART) FIG. 12 discloses an embodiment of a coil 305 disposed far from the open end 701 of the recess 304 close to a flexible ring of magnetically conducting material 401 in the shape of a trough, which trough is in contact with an inside surface 408 of the radial recess 304. A potting material 702 may fill the rest of the recess 304 and hold the coil 305 in place. (PRIOR ART) FIG. 14 shows an embodiment of the invention similar to that shown in (PRIOR ART) FIG. 12, except that the coil 305 is disposed nearer to the open end 701. (PRIOR ART) FIG. 13 shows an embodiment of the invention in which the flexible ring 401 comprises a flexible potting material that holds the coil 305 in place and together they fill the entirety of the radial recess 304. In such an embodiment the flexible potting material comprises a magnetically conductive material such as ferrite or iron powder or shavings.

[0080] (PRIOR ART) FIG. 15 discloses an embodiment in which the flexible ring 401 holds the coil 305 in place and both are disposed near the open end 701 of the radial recess 304. In this embodiment an insulating material 1101 separates the flexible ring 401 and the coil 305 from the surface 408 of the radial recess 304. The insulating 1101 material may be a polyetheretherkeytone, another material, or combinations thereof.

[0081] Referring now to (PRIOR ART) FIG. 16, a single radial recess 304 may comprise a plurality of flexible rings 401. Each flexible ring 401 may comprise a coil 305 with the same or a different number of turns as the coils 305 in the other flexible rings 401. The coil 305 in each ring 401 may be the same coil 305 or a different coil 305. The coil or plurality of coils 305 in the plurality of rings 401 may be energized independently. Although specific orientations and/or placements of coil 305, flexible ring 401 and radial recess 304 have been shown, this may not be construed to exclude other possible orientations, arrangements or combinations from being included within the scope of the claims of the present invention. These rings may be electrically and/or magnetically isolated from each other. This may be accomplished by spacers between them. In some embodiments, the radial recess may be formed in such a way to shield the rings from each other.

[0082] (Prior Art) FIGS. 17-20 are perspective diagrams of various embodiments of flexible rings 401 comprising ferrite segments 402 joined flexibly together. (PRIOR ART) FIG. 17 discloses adjacent ferrite segments 402 joined together by a flexible backing 407. In this embodiment of the invention the flexible backing 407 comprises a single piece around multiple segments of the ring 401. The flexible backing may comprise an adhesive, a tape, a string, or combinations thereof.

[0083] Referring now to (PRIOR ART) FIG. 18, another embodiment of a flexible backing 407 is disclosed, in which the backing connects two segments together. In this embodiment flexible backing segments 1401 are shown. Flexible backing segments 1401 may be advantageous for ease of assembly and disassembly of the ring 401. Flexible backing segments 1401 may comprise a tape, an adhesive, or other components.

[0084] Referring now to (PRIOR ART) FIG. 19, an embodiment of a flexible ring 401 is shown in which adjacent ferrite segments 402 are joined flexibly together using a string 1501. In some embodiments of the invention a hinge may connect adjacent segments 402. In other embodiments the ferrite segments may be profiled such that the ends of the ferrite segments may be angled such that they are complimentary to each other as they form a ring. In this manner gaps between the segments may be reduced. In some embodiments, the ferrite powder or other magnetically conductive material may be packed into the gaps to prevent magnetic leakage.

[0085] Referring now to (PRIOR ART) FIG. 20, an embodiment of a flexible ring 401 is shown in which segments of ferrite 402 are joined flexibly together using a frame or a brace 1601. The brace 1601 may comprise a rigid though somewhat flexible material such that each of the two sides 1602 may move laterally apart, in order that a ferrite segment 402 may be slid into place. Once the ferrite segment 402 is in place the sides 1602 of the brace 1601 may return to their original position and hold the segment 402 in place. Although a specific embodiment of a brace 1601 has been shown, this may not be construed to suggest that other embodiments of braces 1601 or other such form creating structures are not also consistent with the invention.

[0086] (Prior Art) FIGS. 21, 22 are taken from the '575 reference and depict a perspective view of a mesh housing and cross-section view of a transmission device or inductive coupler, respectively. These FIGS. are described if further detail in said reference.

[0087] Whereas the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.