WO1988001096A1 - Rotary signal coupler - Google Patents
Rotary signal coupler Download PDFInfo
- Publication number
- WO1988001096A1 WO1988001096A1 PCT/GB1987/000554 GB8700554W WO8801096A1 WO 1988001096 A1 WO1988001096 A1 WO 1988001096A1 GB 8700554 W GB8700554 W GB 8700554W WO 8801096 A1 WO8801096 A1 WO 8801096A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- primary
- winding
- rotary coupling
- primary winding
- secondary winding
- Prior art date
Links
- 238000004804 winding Methods 0.000 claims description 31
- 230000008878 coupling Effects 0.000 claims description 21
- 238000010168 coupling process Methods 0.000 claims description 21
- 238000005859 coupling reaction Methods 0.000 claims description 21
- 239000010410 layer Substances 0.000 claims description 4
- 230000001939 inductive effect Effects 0.000 claims description 3
- 239000002356 single layer Substances 0.000 claims description 3
- 229910000859 α-Fe Inorganic materials 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 2
- 239000000523 sample Substances 0.000 description 10
- 238000007689 inspection Methods 0.000 description 6
- 230000004907 flux Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
- E21B47/13—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/18—Rotary transformers
Definitions
- This invention relates to a coupling for transmitting electrical signals between first and second members which undergo relative rotation.
- the invention is particularly, but not exclusively, of relevance to the inspection of long hollow cylindrical objects, such as drill collars for oil boreholes.
- a drill collar typically has a length of 10 m and an internal bore of about 78 mm; this makes i ⁇ .ternal inspection for cracks and the like difficult-
- an electro.— magnetic inspection apparatus using a probe with twin windings This apparatus is suitable for detecting defects of interest in drill collars and the like, but it is necessary to scan the probe over the internal surface. One way of doing this would be to draw through the bore on which the probe is rotatably mounted, so that spiral scan is performed. However, it is necessary to couple the signals from the rotating probe to a non-rotating instrument including a bridge circuit.
- the parameter of interest is a small out-of-balance quantity, it is very easy for this to be swamped by noise in the coupling. It has also been found that the signal of interest can be swamped by spurious signals arising from non-uniformity of rotational and translational movement.
- an object of the present invention is to provide a coupling of the kind stated and which provides low noise and a high immunity to non-uniform movemen .
- the invention provides a rotary coupling for transferring an electrical signal between first and second members arranged to undergo relative rotation, comprising a primary winding on the first member, and a secondary winding on the second member adjacent the primary winding for inductive coupling therewith, the primary winding having a given linear extent and the secondary winding being positioned within a minor part of and spaced from the ends of said linear extent.
- the first member is a shaft and the second member a surrounding sleeve.
- the primary winding is a'single-layer coil of length A on the shaft surface, and the secondary a multi- ⁇ 0 layer coil of length B on the sleeve adjacent the centre of the primary.
- the face of the primary winding away from the secondary winding is covered with a ferrite material.
- Fig 1 is a perspective view of an inspection apparatus incorporating the invention
- Fig 2 is a diagrammatic cross-section of a coupling embodying the invention for use in the apparatus of Fig 1; 20 Fi 3 is a similar view of an alternative embodiment of the coupling; and
- Fig 4 is a side view, partly in cross-section, of a further embodiment.
- the inspection apparatus shown in Fig 1 comprises a cylindrical 25 body 10 dimensioned to be pulled through the bore of a tubular member by a cable 12.
- the body 10 has spring-biased wheels 14 for engagement with the bore.
- a probe 16 suitably of the type described in EP-A-0033802, is mounted in a holder 18 which is rotatable with respect to the body 10, to produce a helical scanning pattern.
- the probe and holder are attached to a shaft 20 rotatable within a sleeve 22.
- the two windings of the probe 16 are connected each to a respective primary winding 24a, 24b, which are single-layer windings formed over ferrite layers 26a, 26b in circumferential grooves in the outer surface of the 35 shaft 20.
- Each primary winding 24a, 24b is inductively coupled with a respective secondary winding 28a, 28b, these being multi-layer windings formed in narrow slots in the sleeve 22.
- the linear extent A of the primary windings 24 is considerably larger than the linear extent B of the secondary windings.
- the purpose is to position the secondary winding in an area of uniform flux from its primary, and to avoid coupling in the end zone of the primary where flux concentration occurs.
- Fig 3 operates in a similar manner and like parts are denoted by like references.
- the primary windings 24 are disc-shaped in a transversely extending flange 30 and are coupled with secondary windings 28 in an annular housing 32.
- Bearings.34 journal the shaft 20 for rotation in the housing 32.
- Fig 4 illustrates the invention applied to the inspection of a narrow-bore tube 40 having a bore too small to accept the rotary coupling.
- a probe 16 is mounted on the end of a rod 42 for rotation and translation within the tube 40.
- Bearing means indicated at 44 are provided for locating the probe 16 within the tube 40.
- the rod 42 is rotated b.y a drive assembly 46 embodying the coupling described above and located outside the tube 40. It will be understood that the rod 42 houses conductors connecting the probe 16 to the inductive coupling.
- the rod 42 is sectional, the sections being provided with mechanical screw or bayonet connectors and mating electrical contacts. This permits long tubing to be inspected with the drive assembly requiring axial movement only by the section length.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Geology (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Power Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Electromagnetism (AREA)
- Geophysics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Signals are coupled between a shaft (20) and a housing (22) which rotate relative to each other by means of a primary coil (24) inductively coupled with a secondary coil (26). The primary coil (24) has a relatively large extent (A) and the secondary coil has a much smaller extent (B) and is positioned at the centre of the primary (24). Suitably A/B 6.
Description
Rotary Signal Coupler
This invention relates to a coupling for transmitting electrical signals between first and second members which undergo relative rotation.
The invention is particularly, but not exclusively, of relevance to the inspection of long hollow cylindrical objects, such as drill collars for oil boreholes. A drill collar typically has a length of 10 m and an internal bore of about 78 mm; this makes iπ.ternal inspection for cracks and the like difficult- In our EP-A-0 033802 there is disclosed an electro.— magnetic inspection apparatus using a probe with twin windings. This apparatus is suitable for detecting defects of interest in drill collars and the like, but it is necessary to scan the probe over the internal surface. One way of doing this would be to draw through the bore on which the probe is rotatably mounted, so that spiral scan is performed. However, it is necessary to couple the signals from the rotating probe to a non-rotating instrument including a bridge circuit. Since the parameter of interest is a small out-of-balance quantity, it is very easy for this to be swamped by noise in the coupling. It has also been found that the signal of interest can be swamped by spurious signals arising from non-uniformity of rotational and translational movement.
Accordingly, an object of the present invention is to provide a coupling of the kind stated and which provides low noise and a high immunity to non-uniform movemen . The invention provides a rotary coupling for transferring an electrical signal between first and second members arranged to undergo relative rotation, comprising a primary winding on the first member, and a secondary winding on the second member adjacent the primary winding for inductive coupling therewith,
the primary winding having a given linear extent and the secondary winding being positioned within a minor part of and spaced from the ends of said linear extent.
Preferably there are two primary and two secondary windings, both pairs being as specified in the preceding paragraph, for coupling two signals.
In a preferred form, the first member is a shaft and the second member a surrounding sleeve. The primary winding is a'single-layer coil of length A on the shaft surface, and the secondary a multi- ^0 layer coil of length B on the sleeve adjacent the centre of the primary. Suitably A/B 6.
Preferably, the face of the primary winding away from the secondary winding is covered with a ferrite material.
Embodiments of the invention will now be described, by way l ~- of example, with reference to the drawings, in which:-
Fig 1 is a perspective view of an inspection apparatus incorporating the invention;
Fig 2 is a diagrammatic cross-section of a coupling embodying the invention for use in the apparatus of Fig 1; 20 Fi 3 is a similar view of an alternative embodiment of the coupling; and
Fig 4 is a side view, partly in cross-section, of a further embodiment.
The inspection apparatus shown in Fig 1 comprises a cylindrical 25 body 10 dimensioned to be pulled through the bore of a tubular member by a cable 12. The body 10 has spring-biased wheels 14 for engagement with the bore. A probe 16, suitably of the type described in EP-A-0033802, is mounted in a holder 18 which is rotatable with respect to the body 10, to produce a helical scanning pattern. 30 Referring to Fig 2, the probe and holder are attached to a shaft 20 rotatable within a sleeve 22. The two windings of the probe 16 are connected each to a respective primary winding 24a, 24b, which are single-layer windings formed over ferrite layers 26a, 26b in circumferential grooves in the outer surface of the 35 shaft 20.
Each primary winding 24a, 24b is inductively coupled with a respective secondary winding 28a, 28b, these being multi-layer
windings formed in narrow slots in the sleeve 22.
In accordance with the invention, the linear extent A of the primary windings 24 is considerably larger than the linear extent B of the secondary windings. The purpose is to position the secondary winding in an area of uniform flux from its primary, and to avoid coupling in the end zone of the primary where flux concentration occurs.
This minimises noise induced by axial movement between the shaft and the sleeve, or lack of concentricity in the rotational movement. It has been found that A/B _ 6 is suitable, and that
(while the coupling efficiency is poor) induced noise is very low.
The alternative embodiment shown in Fig 3 operates in a similar manner and like parts are denoted by like references. In this case, however, the primary windings 24 are disc-shaped in a transversely extending flange 30 and are coupled with secondary windings 28 in an annular housing 32. Bearings.34 journal the shaft 20 for rotation in the housing 32.
Fig 4 illustrates the invention applied to the inspection of a narrow-bore tube 40 having a bore too small to accept the rotary coupling. A probe 16 is mounted on the end of a rod 42 for rotation and translation within the tube 40. Bearing means indicated at 44 are provided for locating the probe 16 within the tube 40. The rod 42 is rotated b.y a drive assembly 46 embodying the coupling described above and located outside the tube 40. It will be understood that the rod 42 houses conductors connecting the probe 16 to the inductive coupling.
Preferably, the rod 42 is sectional, the sections being provided with mechanical screw or bayonet connectors and mating electrical contacts. This permits long tubing to be inspected with the drive assembly requiring axial movement only by the section length.
Claims
1. A rotary coupling for transferring an electrical signal between first and second members arranged to undergo relative rotation, comprising a primary winding on the first member, and a secondary winding on the second member adjacent the primary winding for inductive coupling therewith, the primary winding having a given linear extent and the secondary winding being positioned within a minor part of and spaced from the ends of said linear extent..
2. A rotary coupling having two primary and twerrseeαπda-ry windings, arranged in pairs of a primary and a secondary winding, each pair being in accordance with claim ~.r. for coupling two signals.
3. A rotary coupling according to claim 1, in which the first member is a shaft and the second member is a sleeve.
4. A rotary coupling according to claim 3, in which the primary winding is a single—layer coil of length A on the shaft surface, and the secondary a multi-layer coil of length B on the sleeve adjacent the centre of the primary.
5. A rotary coupling according to claim 4, in which A:B is equal to or greater than 6.
6. A rotary coupling according to claim 1, in which the face of the primary winding away from the secondary winding is covered with a ferrite material.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8619316 | 1986-08-07 | ||
GB868619316A GB8619316D0 (en) | 1986-08-07 | 1986-08-07 | Rotary signal coupler |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1988001096A1 true WO1988001096A1 (en) | 1988-02-11 |
Family
ID=10602391
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1987/000554 WO1988001096A1 (en) | 1986-08-07 | 1987-08-03 | Rotary signal coupler |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0277169A1 (en) |
GB (1) | GB8619316D0 (en) |
WO (1) | WO1988001096A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0399987A1 (en) * | 1989-05-23 | 1990-11-28 | Smet-Hole, Naamloze Vennootschap | Device and method for signal transmission in drill stems |
FR2661511A1 (en) * | 1990-04-27 | 1991-10-31 | Geophysique Cie Gle | Device for acquiring a seismic signal emitted by a rotating drilling bit (tool) |
US5248857A (en) * | 1990-04-27 | 1993-09-28 | Compagnie Generale De Geophysique | Apparatus for the acquisition of a seismic signal transmitted by a rotating drill bit |
GB2280315A (en) * | 1993-07-19 | 1995-01-25 | Secr Defence | Rotatable electric transformer coupling |
WO1996000836A1 (en) * | 1994-06-30 | 1996-01-11 | Expro North Sea Limited | Downhole data transmission |
US6670880B1 (en) | 2000-07-19 | 2003-12-30 | Novatek Engineering, Inc. | Downhole data transmission system |
US6717501B2 (en) | 2000-07-19 | 2004-04-06 | Novatek Engineering, Inc. | Downhole data transmission system |
US6830467B2 (en) | 2003-01-31 | 2004-12-14 | Intelliserv, Inc. | Electrical transmission line diametrical retainer |
US7019665B2 (en) | 2003-09-02 | 2006-03-28 | Intelliserv, Inc. | Polished downhole transducer having improved signal coupling |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3519969A (en) * | 1968-11-12 | 1970-07-07 | Caterpillar Tractor Co | Rotating transformer |
DE1920890A1 (en) * | 1969-04-24 | 1970-11-12 | Guenther Vogeler | Slip-ringless inductive transmitter |
GB2058475A (en) * | 1979-08-31 | 1981-04-08 | Westinghouse Electric Corp | Inductive coupler |
JPH06120308A (en) * | 1992-10-09 | 1994-04-28 | Toshiba Corp | Test method for semiconductor wafer |
-
1986
- 1986-08-07 GB GB868619316A patent/GB8619316D0/en active Pending
-
1987
- 1987-08-03 EP EP87904924A patent/EP0277169A1/en not_active Withdrawn
- 1987-08-03 WO PCT/GB1987/000554 patent/WO1988001096A1/en not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3519969A (en) * | 1968-11-12 | 1970-07-07 | Caterpillar Tractor Co | Rotating transformer |
DE1920890A1 (en) * | 1969-04-24 | 1970-11-12 | Guenther Vogeler | Slip-ringless inductive transmitter |
GB2058475A (en) * | 1979-08-31 | 1981-04-08 | Westinghouse Electric Corp | Inductive coupler |
JPH06120308A (en) * | 1992-10-09 | 1994-04-28 | Toshiba Corp | Test method for semiconductor wafer |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN, Vol. 10, No. 168 (E-411)(2224), 14 June 1986 see the whole document & JP, A, 6120308 (Pioneer K.K.) 29 January 1986 * |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0399987A1 (en) * | 1989-05-23 | 1990-11-28 | Smet-Hole, Naamloze Vennootschap | Device and method for signal transmission in drill stems |
WO1990014497A2 (en) * | 1989-05-23 | 1990-11-29 | Eastman Christensen Gmbh | Process and device for transmitting data signals and/or control signals in a pipe train |
WO1990014497A3 (en) * | 1989-05-23 | 1991-01-10 | Eastman Christensen Gmbh | Process and device for transmitting data signals and/or control signals in a pipe train |
FR2661511A1 (en) * | 1990-04-27 | 1991-10-31 | Geophysique Cie Gle | Device for acquiring a seismic signal emitted by a rotating drilling bit (tool) |
US5248857A (en) * | 1990-04-27 | 1993-09-28 | Compagnie Generale De Geophysique | Apparatus for the acquisition of a seismic signal transmitted by a rotating drill bit |
GB2280315A (en) * | 1993-07-19 | 1995-01-25 | Secr Defence | Rotatable electric transformer coupling |
WO1996000836A1 (en) * | 1994-06-30 | 1996-01-11 | Expro North Sea Limited | Downhole data transmission |
US6670880B1 (en) | 2000-07-19 | 2003-12-30 | Novatek Engineering, Inc. | Downhole data transmission system |
US6717501B2 (en) | 2000-07-19 | 2004-04-06 | Novatek Engineering, Inc. | Downhole data transmission system |
US6830467B2 (en) | 2003-01-31 | 2004-12-14 | Intelliserv, Inc. | Electrical transmission line diametrical retainer |
US7019665B2 (en) | 2003-09-02 | 2006-03-28 | Intelliserv, Inc. | Polished downhole transducer having improved signal coupling |
Also Published As
Publication number | Publication date |
---|---|
GB8619316D0 (en) | 1986-09-17 |
EP0277169A1 (en) | 1988-08-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0678880B1 (en) | Inductive coupler for well tools | |
JP3315987B2 (en) | Sensor system | |
CA1273998A (en) | Circumferentially compensating eddy current probe with alternately polarized transmit coils and receiver coils | |
US4856337A (en) | Apparatus and method for providing a combined ultrasonic and eddy current inspection of a tube | |
CA2245419A1 (en) | Device for inspection of water pipelines and method | |
WO1988001096A1 (en) | Rotary signal coupler | |
US4955235A (en) | Apparatus and method for providing a combined ultrasonic and eddy current inspection of a metallic body | |
US5670878A (en) | Inspecting a conductive object with a steady state magnetic field and induced eddy current | |
US20100206064A1 (en) | Casing Inspection Logging Tool | |
EP0076684B1 (en) | Detecting flaws in the threaded end of an elongate member such as a pipe | |
GB2201789A (en) | Circumferentially compensating eddy current probe | |
CN1461871A (en) | Joint for wire pipe with current loop inductive coupler | |
JP2002327889A (en) | Probe | |
US5174165A (en) | Flexible delivery system for a rotatable probe | |
US4480225A (en) | Improved multi-directional eddy current inspection test apparatus for detecting flaws in metal articles | |
US4690006A (en) | Jig for carrying out movement and alignment within a pipe | |
JPH11502938A (en) | Eddy current sensor and tube inspection device having at least one sensor | |
WO2007005517A2 (en) | Rft pipeline inspection system and method therefor | |
US5134367A (en) | Rotating eddy current roller head for inspecting and profiling tubing having two separate cross wound coils | |
US20100207711A1 (en) | Capacitive Signal Coupling Apparatus | |
US4448084A (en) | Non-contacting shaft position sensor | |
US5187435A (en) | Non-destructive test apparatus with eddy current transducer rotary head and field homogenizing conductive ring for scanning metal test materials | |
US4734642A (en) | Device for use in eddy current testing for transmission of signals between a signal processing device and a signal source | |
US6705761B1 (en) | Bearing with integral transformer | |
JP2953637B2 (en) | Flexible delivery device for rotatable probe |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LU NL SE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1987904924 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 1987904924 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1987904924 Country of ref document: EP |