GB2232250A - Ultrasonic testing of mineral insulated cable during manufacture - Google Patents
Ultrasonic testing of mineral insulated cable during manufacture Download PDFInfo
- Publication number
- GB2232250A GB2232250A GB9007644A GB9007644A GB2232250A GB 2232250 A GB2232250 A GB 2232250A GB 9007644 A GB9007644 A GB 9007644A GB 9007644 A GB9007644 A GB 9007644A GB 2232250 A GB2232250 A GB 2232250A
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- United Kingdom
- Prior art keywords
- advancing
- tube
- continuously
- cable
- mineral insulated
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
- G01N29/27—Arrangements for orientation or scanning by relative movement of the head and the sensor by moving the material relative to a stationary sensor
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
In a method of manufacturing mineral insulated cable in which the metal tube from which the sheath is to be formed is formed from an advancing metal strip (T) which is folded into tubular form and whose edges are continuously welded together (25), any defects in the weld are identified and located by continuously introducing ultrasonic vibrations into the welded region. These vibrations either interact with a defect in the welded region to produce an echo or undergo a change in signal strength arising from transmission past a defect. The advancing tube is continuously monitored to detect any echo or change in signal strength caused by such a defect or a fault in the insulation and, in response to any such identification, the advancing tube is automatically marked to indicate the location of the defect. <IMAGE>
Description
MINERAL INSULATED CABLE MANUFACTURE
This invention relates to a method of, and apparatus for, manufacturing mineral insulated electric cables, that is to say cables of the kind comprising at least one elongate conductor insulated from a surrounding sheath of metal or metal alloy, and where there is more than one elongate conductor from the other conductor or conductors, by compacted mineral insulating powder, usually but not necessarily magnesium oxide.
In one method of manufacturing mineral insulated electric cable currently employed, a metal tube is continuously formed from an advancing ductile metal strip which is transversely folded into tubular form and whose edges are continuously welded together while mineral insulating powder and a conductor rod or conductor rods are simultaneously introduced into the tube so formed, the powder is densely packed in the tube and around the conductor rod or rods, and the filled tube is then caused to travel through a die or dies or other means to reduce it to the required cross-sectional size. For convenience, this known method of manufacturing mineral insulated electric cable will hereinafter be referred to as "the method of manufacturing mineral insulated electric cable as hereinbefore defined".
As the method of manufacturing mineral insulated electric cable as hereinbefore defined is a continuous process, it is desirable that any defects in the continuously formed weld of the advancing metal tube can be readily identified and located and that important parameters of the cable under manufacture can be continuously monitored to ensure that these parameters do not stray outside acceptable limits.
It is an object of the present invention to provide, in the method of manufacturing mineral insulated electric cable as hereinbefore defined, an improved method of continuously identifying and locating any defects in the continuously formed weld of the metal tube.
According to the invention, in the method of manufacturing mineral insulated electric cable as hereinbefore defined, ultrasonic vibrations are continuously introduced into the welded region of the advancing metal tube, which vibrations either will interact with a defect in the welded region to produce an echo or will undergo a change in signal strength arising from transmission past a defect; the advancing metal tube is continuously monitored to detect any echo or change in signal strength caused by a defect thereby identifying the existence of a defect in the weld region; and, in response to any such identification, the advancing metal tube is automatically marked to indicate the location of said defect.
Preferably, ultrasonic vibrations are continuously introduced into the welded region of the advancing metal tube upstream of the die or dies or other reducing means but, alternatively or additionally, ultrasonic vibrations may be continuously introduced into the welded region of the sheath of the continuously advancing mineral insulated electric cable downstream of the die or dies or other reducing means and/or, where two or more dies or other reducing means are employed, into the welded region of the sheath of the partly formed mineral insulated electric cable at a position between two dies or other reducing means.
Defects that can be identified and located using the technique of ultrasound include any position of discontinuity in the weld, any position along the weld where there is an undesirable lack of weld penetration, any position along the weld where the thickness of the weld is either too thin or too thick, and any position in the weld where there is a bubble or other fault which might prove troublesome either when the metal tube is reduced in cross-sectional size or when the mineral insulated electric cable is in use.
In addition to identifying and locating any defect in the continuously formed weld of the advancing metal tube, preferably ultrasonic vibrations are also continuously introduced into the advancing metal tube at at least one position circumferentially spaced with respect to the welded region to identify and locate by the improved method hereinbefore described any defect in the tube itself.
Preferably, downstream of the die or dies or other reducing means, ultrasonic vibrations are continuously introduced into the continuously advancing mineral insulated electric cable, which vibrations will interact with the compacted powder, with the tube and with the or each conductor embedded therein to produce a substantially continuous echo or other signal, the advancing cable is continuously monitored to detect any significant change in the continuous echo or other signal produced by said ultrasonic vibrations thereby identifying a change within the cable and, in response to any such change, the advancing cable is automatically marked to indicate the location of said change. where there are two or more dies or other reducing means, such ultrasonic vibrations may be continuously introduced into the continuously advancing partially formed mineral insulated electric cable at a position between two dies or other reducing means.
In this way, continuous introduction of ultrasonic vibrations into the advancing mineral insulated electric cable and detection of any significant change in the continuous echo produced by said ultrasonic vibrations can be employed to monitor continuously for a change in the degree of compaction and continuity of the powder filling of the cable sheath, for a change in the continuity of the or each conductor since a break in a conductor will result in a localised reduction in the density of the powder filling, and for a change in the position of the or each conductor with respect to the cable sheath and, where there is more than one conductor, with respect to the other conductor or conductors.
In all cases, echoes or other signals caused by a defect in the continuously formed weld of the advancing metal tube or in the tube itself, and in some instances by a change in a parameter of the mineral insulated electric cable, may be used to adjust automatically apparatus or other equipment employed in the manufacture of the mineral insulated electric cable.
To reduce substantially undesirable errors in the received echoes or other received signals arising from any transverse movement of the advancing metal tube or the advancing mineral insulated electric cable, preferably in each case ultrasonic vibrations are continuously introduced into the metal tube or electric cable and are continuously monitored at substantially diametrically opposed positions so that any variations in the received echoes or other signals will to all intents and purposes be cancelled out.
In each case, preferably, the continuously welded metal tube, and when desired the mineral insulated electric cable, is caused to travel continuously through a magnetic field in which at least one coil is located between the advancing tube or electric cable and one of two magnetic pole pieces establishing the field and an
R.F. current is passed through the coil. Preferably, two coils are so located1 one acting as a transmitter and the other acting as a receiver, and an R.F. current is passed through the transmitting coil. The R.F.
current introduces eddy currents in the surface of the advancing tube or electric cable which, in turn, interact with the magnetic field and produce in the surface of the tube or cable an oscillating force which generates ultrasonic vibrations that pass through the thickness of the tube or cable. These ultrasonic waves interact with any defect in the weld or in the tube itself, or any change in a parameter of the mineral insulated electric cable, to produce echoes or other signals which are picked up either by the coil acting as a receiver or by the separate receiving coil.
Where two coils are employed, preferably they are longitudinally spaced in the direction of travel of the advancing tube or electric cable and may be located transversely of the longitudinal axis of the advancing tube or cable; if desired, one coil may be circumferentially spaced with respect to the other coil.
Alternatively, the two longitudinally spaced coils may be so disposed that the advancing tube or electric cable passes through the turns of each coil. The disposition of the coils will depend on whether the tube or electric cable is being continuously monitored and the form of defect in the weld or tube, or of a parameter of the cable being detected and located.
The invention also includes improved apparatus for continuously monitoring for any defects in the weld being continuously formed in the metal tube during manufacture of mineral insulated electric cable by the method hereinbefore defined.
The invention further includes improved apparatus for continuously monitoring for any defects in a mineral insulated electric cable manufactured by the method of manufacturing mineral insulated electric cable by the method hereinbefore defined.
The invention is further illustrated by a description, by way of example, of the preferred method of continuously manufacturing a mineral insulated electric cable in which the metal sheath tube is continuously formed by transversely folding an advancing ductile metal strip into tubular form and welding the edges of the advancing strip together, with reference to the accompanying drawings, in which::
Figure 1 is a diagrammatic side view of the preferred apparatus for use in the preferred method;
Figure 2 is a diagrammatic transverse cross-sectional view of the powder delivery tube of the preferred apparatus taken on the line II-II in Figure 1, drawn on an enlarged scale;
Figure 3 is a diagrammatic side view of the weld monitoring station of the preferred apparatus;
Figure 4 is a diagrammatic transverse cross-sectional view of the powder delivery tube of the preferred apparatus taken on the line IV-IV in Figure 3, drawn on an enlarged scale;
Figure 5 is a diagrammatic side view of the tube monitoring station of the preferred apparatus;;
Figure 6 is a diagrammatic transverse cross-sectional view of the powder delivery tube of the preferred apparatus taken on the line VI-VI in Figure 5, drawn on an enlarged scale, and
Figure 7 is a diagrammatic side view of the cable monitoring station of the preferred apparatus.
Referring to Figures 1 and 2, the preferred apparatus for use in the preferred method of manufacturing mineral insulated electric cable comprises a powder delivery tube 1 which over a major part of its length is disposed substantially horizontally and which, over a minor part 2 of its length at its upstream end, is smoothly curved in an upward direction. The minor end part 2 of the delivery tube 1 constitutes one branch of a bifurcated tubular fitting 3, the second branch 4 of which is in axial alignment with the major part of the length of the delivery tube 1. Positioned above and upstream of the minor end part 2 of the delivery tube 1 is a fluid-tight main chamber 7 for mineral insulating powder, which chamber is detachably connected to the minor end part of the delivery tube by a smoothly curved pipe 6.A fluid-tight supplementary powder chamber 11 for automatically re-charging the main chamber 7 is disposed above and connected via an automatically operable valve 12 to the main chamber. The main powder chamber 7 and the supplementary powder chamber 11 are also interconnected by a pipe 9 in which is fitted an automatically operable valve 10. The supplementary powder chamber 11 has at its upper end an outlet pipe 16 open to the atmosphere in which is an automatically operable valve 13. Hopper 15 mounted above the supplementary powder chamber 11 and fed with mineral insulating powder from a bulk source (not shown) is connected to the supplementary powder chamber via an automatically operable valve 14.The main powder chamber 7 incorporates a level sensor 18 for detecting a predetermined minimum level of powder in the chamber and the supplementary powder chamber 11 has a level detector 19 for detecting a predetermined maximum level of powder in the supplementary chamber. Clean dry air from a source (not shown) is continuously injected into the main powder chamber 7 through a pipe 20 via a pressure controller 21, an accumulator 22 and a valve 23, the pressure of the clean dry air being recorded by a gauge 24. Within the main powder chamber 7, the pipe 20 extends around the chamber and has in its wall a multiplicity of mutually spaced apertures through which dry clean air under the required predetermined pressure is expelled in a plurality of directions into the chamber.A rotatably driven screw (not shown) may be so disposed in the main powder chamber 7 that, when the screw is rotatably driven about its axis, mineral insulating powder is encouraged to flow towards the outlet of the chamber and down the pipe 6.
Intermediate of the ends of the powder delivery tube 1 is a welding station 25 at which the edges of an advancing ductile metal strip T, which is travelling in the direction of its length and is being transversely folded into tubular form around the powder delivery tube so that it surrounds and is radially spaced from the delivery tube, are continuously welded together to form a metal sheathed tube into which mineral insulating powder is to be fed and partially compacted around advancing conductor rods C at a required fill density.
Downstream of the welding station 25 is a weld monitoring station 70 (Figures 2, 3 & 4) at which any defects in the continuously formed weld W of the metal tube T are continuously identified and located.
Downstream of the weld monitoring station 70 is a tube monitoring station 80 at which any defects in the metal tube T itself are continuously identified and located.
Detachably connected to the downstream end of the powder delivery tube 1 is a separately formed fitting 26 which incorporates or constitutes filtered outlets port 27 through which air is expelled from the delivery tube, at least one spacer member for locating the conductor rods C positively with respect to the advancing metal tube T, a passage or passages 29 for flow of powder from the delivery tube into the metal tube and filtering means 28 disposed between the fitting and the metal tube downstream of the filtered outlet ports.
The powder delivery tube 1 has, extending from immediately upstream of the fitting 26 to a position downstream of the bifurcated fitting 3, four circumferentially spaced radially outwardly extending longitudinally continuous ribs 53 which bear against and space the advancing metal tube T from the delivery tube and which define independent longitudinally extending passages 54, 55, 56 and 57. The downstream ends of the passages 56 and 57 are closed by deflectors 58. The upstream ends of passages 54 and 55 may be open to the atmosphere via a filter bag (not shown) or may be connected to a re-claim or re-cycling plant. Upstream of their closed downstream ends, passages 56 and 57 may be interconnected.
Downstream of the separately formed fitting 26 are rolls 90 for reducing the cross-sectional size of the powder filled tube T and downstream of the rolls is a cable monitoring station 95 at which any change in a parameter of the mineral insulated electric cable can be identified and located.
Referring to Figures 3 and 4, the weld monitoring station 70 comprises two magnetic pole pieces (not shown) establishing a magnetic field through which the metal tube T is caused to pass and a transmitter coil 71 and a receiver coil 75 which are longitudinally spaced in the direction of travel of the advancing metal tube and are positioned on diametrically opposite sides of the tube. A signal generator 73 is operatively coupled to the transmitter coil 71 via an amplifier 72; the receiver coil 75 is operatively coupled to a signal processor 77 via an amplifier 76. An R.F. current is passed through the transmitter coil 71 which introduces eddy currents in the surface of the advancing metal tube which, in turn, interact with the magnetic field and produce in the surface of the tube an oscillating force which generates ultrasonic vibrations that pass through the thickness of the tube.These ultrasonic waves interact with any defect in the weld W to produce echos or other signals which are picked up by the receiver coil 75. The signal processor 77 generates an output proportional to the amplitude of the echos or other signals picked up by the receiver coil 75 and the output signal is employed to actuate means (not shown) which automatically marks the advancing metal tube T to indicate the location of the defect.
The tube monitoring station 80 shown in Figures 5 and 6 comprises two magnetic pole pieces (not shown) which establish a magnetic field through which the advancing metal tube T passes and a transmitter coil 81 and a receiver coil 85 longitudinally spaced in the direction of travel of the advancing tube and circumferentially spaced around the periphery of the tube by a circumferential distance substantially less than one quarter of the circumference of the tube. A signal generator 83 is operatively coupled to the transmitter coil 81 via an amplifier 82; the receiver coil 85 is operatively coupled to a signal processor 87 via an amplifier 86.An R.F. current passed through the transmitter coil 81 introduces eddy currents in the surface of the advancing metal tube which, in turn, interact with the magnetic field and produce in the surface of the tube an oscillating force which generates ultrasonic vibrations that pass through the thickness of the tube. These ultrasonic waves interact with any defect in the tube to produce echos or other signals which are picked up by the receiver coil 85. The transmitter and receiver coils 81 and 85 are so located as to create a spiral of signal in the wall of the advancing metal tube T which extends for a circumferential distance greater than 3600 to ensure that any defect in the wall of the tube is identified at least once.Care is taken to so locate the transmitter coil 81 and receiver coil 85 relative to the position of the weld W that the spiral of signal in the wall of the tube passes through the weld only once, thereby avoiding duplicate identification of any defect in the weld. If desired, the tube monitoring station may serve the dual purpose of monitoring for defects in the weld W and for defects in the wall of the tube T.
The cable monitoring station 95 shown in Figure 7 is positioned downsteam of the reducing rolls 90 and comprises two magnetic pole pieces (not shown) which establish a magnetic field through which the advancing metal tube passes, a transmitter coil 96 through which the advancing metal tube T passes and to which a signal generator (not shown) is operatively coupled via an amplifier and, upstream of the transmitter coil, a receiver coil 99 through which the advancing metal tube passes and which is operatively coupled via an amplifier to a signal processor (not shown). Substantially continuous ultrasonic signals are introduced into the advancing mineral insulated electric cable by means of the transmitter coil 96 and travel along all parts of the mineral insulated electric cable simultaneously to the receiver coil 99.During this transit from transmitter coil 96 to receiver coil 99, the ultrasonic signals interact with the compacted powder, with the tube and with the or each conductor embedded in the powder. The receiver coil 99 continuously monitors the advancing cable to detect any significant change in the continuous signals thereby identifying a change in a parameter of the cable. In response to any such change, an output signal from the signal processor (not shown) automatically causes means (not shown) to mark the location of said change in a parameter of the advancing cable.
The output signal of the signal processor 77, 87 and 99 can also be displayed to an operator, can be analysed and recorded as part of a quality control procedure, and can be used to trigger an alarm if any output signal is such as to indicate the identification of a major defect or if the number of defects identified and located has exceeded an acceptable value.
when using the apparatus illustrated in Figures 1 to 7 in the manufacture of mineral insulated electric cable in which the metal sheathed tube is continuously formed by transversely folding an advancing ductile metal strip in tubular form and welding the edges of the advancing strip together, conductor rods C are continuously fed through the second branch 4 of the bifurcated fitting 3 into the powder delivery tube 1 and the metal tube T is continuously formed by transversely folding the advancing ductile metal strip around the powder delivery tube and continuously welding its edges together as they travel past the welding station 25.
With valve 23 open and valves 10, 12, 13 and 14 closed, clean dry air at a predetermined pressure is injected via the pipe 20 and accumulator 22 into the main powder chamber 7 and mineral insulating powder under the pressure of the clean dry air is continuously fed via the pipe 6 and the minor end part 2 of the powder delivery tube 1 into the powder delivery tube. Clean dry air also at a predetermined pressure is injected into the bifurcated fitting 3 through the inlet port 39 to prevent build up of mineral insulating powder at the intersection of the branches of the fitting.
When the level of mineral insulating powder in the main powder chamber 7 falls to a predetermined level, this low level of powder is detected by the level sensor 18 which automatically initiates a command sequence.
Valve 10 opens to balance the pressures in the main chamber 7 and supplementary chamber 11 and, after a short time delay, valve 12 opens to allow a charge of powder to fall from the supplementary chamber into the main chamber. After a suitable time delay, valve 12 closes, valve 10 closes and then valve 13 opens to relieve the pressure in the supplementary chamber 11.
After a further short time delay, valve 14 opens to allow powder from the hopper 15 to flow into the supplementary chamber 11. When the level of powder in the supplementary chamber 11 has risen to a predetermined level, this high level is detected by the level sensor 19 which automatically causes valves 13 and 14 to close. Normal operation of the apparatus then continues until the level of powder in the main chamber 7 again falls to said predetermined low level when the aforesaid cycle is repeated.
Mineral insulating powder under the pressure of the dry clean air is injected from the powder delivery tube 1 through the bore of the fitting 26 into the advancing metal tube T so that mineral insulating powder fills the space around the conductor rods C and is partially compacted under the pressure of the dry clean air. Dry clean air is expelled through the filtered outlet ports 27, flows back between the powder delivery tube 1 and the advancing metal tube T and is deflected by the deflectors 58 to flow along passages 54 and 55 and convey heat emitted by the advancing metal tube.
Filtering means 28 prevents mineral insulating powder from the metal tube T from flowing back between the metal tube and the fitting. From the passages 54 and 55, the dry clean air may be expelled to the atmosphere via a filter bag (not shown) to catch any stray powder expelled with the air or it may be fed to a re-claim or re-cycling plant.
During passage of the metal tube T through the weld monitoring station 70 downstream of the welding station 25 and through the tube monitoring station 80 downstream of the weld monitoring station 70, the weld W and the metal tube T itself are continuously monitored to identify any defect in the continuously formed weld or in the wall of the metal tube and, when any defect in either the weld or the tube is identified, the advancing metal tube is automatically marked to indicate the position of the defect.
Downstream of the reducing rolls 90, the mineral insulated electric cable passes the cable monitoring station 95 which continuously monitors the advancing cable to identify any change in a parameter of the cable which is automatically marked to indicate the position of any identified change.
The improved method of continuously monitoring for defects in the weld of the metal tube and for continuously monitoring for defects in the mineral insulated cable has the important advantages that no physical contact with the metal tube or mineral insulated cable is necessary, that the fact that the weld of the metal tube is at a high temperature is irrelevant and that the method is applicable to high speed, in-line operation on existing production lines.
Claims (15)
1. A method of manufacturing mineral insulated electric cable in which a metal tube is continuously formed from an advancing ductile metal strip which is transversely folded into tubular form and whose edges are continuously welded together while mineral insulating powder and a conductor rod or conductor rods are simultaneously introduced into the tube so formed, the powder is densely packed in the tube and around the conductor rod or rods, and the filled tube is then caused to travel through a die or dies or other means to reduce it to the required cross-sectional size, wherein ultrasonic vibrations are continuously introduced into the welded region of the advancing metal tube, which vibrations either will interact with a defect in the welded region to produce an echo or will undergo a change in signal strength arising from transmission past a defect; the advancing metal tube is continuously monitored to detect any echo or change in signal caused by a defect thereby identifying the existence of a defect in the welded region; and, in response to any such identification, the advancing metal tube is automatically marked to indicate the location of said defect.
2. A method as claimed in Claim 1, wherein ultrasonic vibrations are continuously introduced into the welded region of the advancing metal tube upstream of the die or dies or other reducing means.
3. A method as claimed in Claim or 2, wherein ultrasonic vibrations are also continuously introduced into the advancing metal tube at at least one position circumferentially spaced with respect to the welded region to identify and locate any defect in the tube itself.
4. A method as claimed in any one of the preceding
Claims, wherein, downstream of the die or dies or other reducing means, ultrasonic vibrations are continuously introduced into the continuously advancing mineral insulated electric cable, which vibrations will interact with the compacted powder, with the tube and with the or each conductor embedded therein to produce a substantially continuous echo or other signal, the advancing cable is continuously monitored to detect any significant change in the continuous echo or other signal produced by said ultrasonic vibrations thereby identifying a change within the cable and, in response to any such change, the advancing cable is automatically marked to indicate the location of said change.
5. A method as claimed in Claim 4 in which the mineral insulated electric cable is caused to travel through two or more dies or other reducing means, wherein said ultrasonic vibrations are continuously introduced into the advancing cable at a position between two dies or other reducing means.
6. A method as claimed in any one of the preceding
Claims, wherein echos or other signals caused by a defect in the continuously formed weld of the advancing metal tube or in the tube itself, and in some instances by a change in a parameter of the advancing mineral insulated electric cable, are caused to adjust automatically apparatus or other equipment employed in the manufacture of the mineral insulated electric cable.
7. A method as claimed in any one of the preceding
Claims, wherein said ultrasonic vibrations are continuously introduced into the advancing metal tube or mineral insulated electric cable and are continuously monitored at substantially diametrically opposed positions.
8. A method as claimed in any one of the preceding
Claims, wherein the continuously welded metal tube, and when desired the mineral insulated electric cable, is caused to travel continuously through a magnetic field in which at least one coil is located between the advancing tube or cable and one of two magnetic pole pieces establishing said field and an R.F. current is passed through the coil.
9. A method as claimed in any one of Claims 1 to 7, wherein the continuously welded metal tube, and when desired the mineral insulated electric, is caused to pass continuously through a magnetic field in which two coils are located between the advancing tube or cable and one of two magnetic pole pieces establishing said field, one coil acting as a transmitter and the other coil acting as a receiver, and an RF current is passed through the transmitter coil.
10. A method as claimed in Claim 9, wherein the two coils are longitudinally spaced in the direction of travel of the advancing tube or cable and are located transversely of the longitudinal axis of the tube or cable.
11. A method as claimed in Claim 10, wherein one coil is circumferentially spaced with respect to the other coil.
12. A method as claimed in Claim 10, wherein the two longitudinally spaced coils are so disposed that the advancing tube or cable passes through the turns of each coil.
13. Apparatus for continuously monitoring for any defects in the weld being continuously formed in the metal tube during manufacture of mineral insulated electric cable by the method claimed in any one of the preceding Claims.
14. Apparatus for continuously monitoring for any defects in the mineral insulated electric cable manufactured by the method claimed in any one of Claims 4 to 12.
15. A method of manufacturing mineral insulated electric cable substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898907613A GB8907613D0 (en) | 1989-04-05 | 1989-04-05 | Mineral insulated cable manufacture |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9007644D0 GB9007644D0 (en) | 1990-05-30 |
| GB2232250A true GB2232250A (en) | 1990-12-05 |
| GB2232250B GB2232250B (en) | 1993-01-06 |
Family
ID=10654466
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB898907613A Pending GB8907613D0 (en) | 1989-04-05 | 1989-04-05 | Mineral insulated cable manufacture |
| GB9007644A Expired - Fee Related GB2232250B (en) | 1989-04-05 | 1990-04-04 | Mineral insulated cable manufacture |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB898907613A Pending GB8907613D0 (en) | 1989-04-05 | 1989-04-05 | Mineral insulated cable manufacture |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2013787C (en) |
| GB (2) | GB8907613D0 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2378027A (en) * | 2001-05-25 | 2003-01-29 | Tiss Ltd | Cargo vehicle alarm activated by breaking conductor loop |
| DE10236495A1 (en) * | 2002-08-09 | 2004-02-26 | Steffen Fleisch | Acoustic production monitoring method for noisy production processes, e.g. welding, whereby the sound of the process is recorded and compared with pre-recorded reference noises to detect a faulty process or error |
| DE102011051166A1 (en) * | 2011-06-17 | 2012-12-20 | Rwth Aachen | Method for detecting detachments in inner boundary surface of cable material during manufacture, involves measuring reflection ultrasonic signal coupled at inner boundary surface of material of cable, as measuring signals |
| EP3967971A1 (en) | 2020-09-10 | 2022-03-16 | Nexans | Non-destructive testing apparatus and method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1584050A (en) * | 1976-09-28 | 1981-02-04 | Hoesch Werke Ag | Ultrasonic testing of material |
| EP0052698A2 (en) * | 1980-11-26 | 1982-06-02 | WIENER KABEL- UND METALLWERKE Gesellschaft m.b.H. | Device for monitoring the production process of cables |
| EP0196144A1 (en) * | 1985-03-26 | 1986-10-01 | Wavin B.V. | A device for measuring the wall thickness of an extruded tubular section during extrusion, extrusion apparatus with such a device and extruded tubular section obtained by using said device |
| EP0206296A1 (en) * | 1985-06-26 | 1986-12-30 | Siemens Aktiengesellschaft | Appliance for the process-integrated testing of moving cylindrical stock |
-
1989
- 1989-04-05 GB GB898907613A patent/GB8907613D0/en active Pending
-
1990
- 1990-04-04 CA CA 2013787 patent/CA2013787C/en not_active Expired - Lifetime
- 1990-04-04 GB GB9007644A patent/GB2232250B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1584050A (en) * | 1976-09-28 | 1981-02-04 | Hoesch Werke Ag | Ultrasonic testing of material |
| EP0052698A2 (en) * | 1980-11-26 | 1982-06-02 | WIENER KABEL- UND METALLWERKE Gesellschaft m.b.H. | Device for monitoring the production process of cables |
| EP0196144A1 (en) * | 1985-03-26 | 1986-10-01 | Wavin B.V. | A device for measuring the wall thickness of an extruded tubular section during extrusion, extrusion apparatus with such a device and extruded tubular section obtained by using said device |
| EP0206296A1 (en) * | 1985-06-26 | 1986-12-30 | Siemens Aktiengesellschaft | Appliance for the process-integrated testing of moving cylindrical stock |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2378027A (en) * | 2001-05-25 | 2003-01-29 | Tiss Ltd | Cargo vehicle alarm activated by breaking conductor loop |
| DE10236495A1 (en) * | 2002-08-09 | 2004-02-26 | Steffen Fleisch | Acoustic production monitoring method for noisy production processes, e.g. welding, whereby the sound of the process is recorded and compared with pre-recorded reference noises to detect a faulty process or error |
| DE102011051166A1 (en) * | 2011-06-17 | 2012-12-20 | Rwth Aachen | Method for detecting detachments in inner boundary surface of cable material during manufacture, involves measuring reflection ultrasonic signal coupled at inner boundary surface of material of cable, as measuring signals |
| EP3967971A1 (en) | 2020-09-10 | 2022-03-16 | Nexans | Non-destructive testing apparatus and method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8907613D0 (en) | 1989-05-17 |
| GB9007644D0 (en) | 1990-05-30 |
| CA2013787A1 (en) | 1990-10-05 |
| GB2232250B (en) | 1993-01-06 |
| CA2013787C (en) | 1994-12-27 |
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| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
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Effective date: 20010404 |