US3662576A - Control for roll gap of a rolling mill - Google Patents

Control for roll gap of a rolling mill Download PDF

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Publication number
US3662576A
US3662576A US28351A US3662576DA US3662576A US 3662576 A US3662576 A US 3662576A US 28351 A US28351 A US 28351A US 3662576D A US3662576D A US 3662576DA US 3662576 A US3662576 A US 3662576A
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inductance
inductances
gap
control
carrier
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Expired - Lifetime
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US28351A
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Siegfried Girlatschek
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Fried Krupp AG
Vereinigte Flugtechnische Werke Fokker GmbH
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Vereinigte Flugtechnische Werke Fokker GmbH
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Assigned to FRIED, KRUPP GMBH, 4300 ESSEN, FED. REP. OF GERMANY reassignment FRIED, KRUPP GMBH, 4300 ESSEN, FED. REP. OF GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MESSERSCHMITT-BOELKOW-BLOHM GMBH
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/58—Roll-force control; Roll-gap control
    • B21B37/62—Roll-force control; Roll-gap control by control of a hydraulic adjusting device
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
    • B21B38/10—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring roll-gap, e.g. pass indicators

Definitions

  • ABSTRACT A feedback control system for a gap between rolls in a mill includes a variable inductance with a core on one roll and an ar mature on the other roll. This inductance, as well as a reference inductance and two auxiliary inductances, are interconnected to establish AC biased bridge. The relative phase of the bridge diagonal voltage is used to control the gap width. The pick up inductance and one of the auxiliary inductance are mounted in physical proximity to each other.
  • the present invention relates to an arrangement and apparatus for controlling the gap or clearance of and between the rolls of a pair of rolls in a rolling mill, to operate by means of automatic control equipment and using particularly inductance means for measuring the width of the gap.
  • the inductance means is to include a core and an armature, and the effective inductivity of that inductance is variable through variation of the air gap between core and armature.
  • the rolled stock has accurate thickness only within a fairly large range of tolerances. In order to narrow the tolerances it is necessary to provide direct control which includes rather exact measuring of the roll gap. Such a requirement for obtaining sufiiciently accurate control is best carried out by means of electronic control and regulating equipment.
  • Another known method for measuring the roll gap is ascertained by contactless gauging.
  • This method utilizes a stationary magnetic field for measuring the roll gap.
  • the strength of the magnetic field is approximately inversely proportional to the roll gap operating as an air gap within the magnetic field path.
  • the dimensions of this air gap are measured by placing Hall generators or indium antimony probes (field plates) into the magnetic field path.
  • the electrical output derivable from these pick up and field sensing element includes indeed representation of the roll gap as an electrical signal.
  • the gap width be represented by variation of an air gap between a core of a pick up inductance and an armature thereof.
  • Armature and core are disposed in two separate carriers which respectively receive journals. of the rolls, so that the distance between core and armature represents the roll gap as air gap in the inductance.
  • the core of this pick up inductance as well as an auxiliary inductance are mounted together in one of the two carriers.
  • These two inductances are included in a bridge as two serial branches connected across a bridgebiasing source.
  • the bridge includes additionally an adjustable inductance to provide a desired or reference value, and another auxiliary inductance completes the bridge.
  • a control signal is derived from one of the diagonals of the bridge. In case the actual value of the roll gap deviates from the desired value, that control signal is used to operate upon a controller for adjusting the roll gap and completing a feedback loop.
  • the inventive arrangement is characterized particularly by a rather simple construction, by insensitivity against mechanical disturbances, and particularly by ready adaption to large and small gaps. Moreover, the resolution of the roll gap measuring method and accuracy thereof are particularly high. Installation of the equipment does not pose difficulties particularly because a reference value of zero for the gap width to be measured can be established simply by moving the armature into engagement with the core corresponding to a gap width zero, and the resulting inductivity defines the base line or zero reference for gap measurement.
  • the combination of pick up inductance and of one of the auxiliary inductances of the bridge provides a pick up device from which, within certain limits, influences of temperature have been eliminated, because both inductances as well as their loss resistances are subjected to the same thermal conditions.
  • Another advantage results from a rather simple layout of the entire electronic circuitry, because voltage and current stabilization is no longer required. Moreover, it is no longer necessary to provide particular linearization as far as relationship of desired and actual value for the gap is concerned. Furthermore, the dynamics of the control loop is independent from the adjusted air gap of the pick up inductance.
  • the arrangement in accordance with the invention is also useful in rolling mills used for rolling ferromagnetic material because the low AC induction in the gap area is insufficient to attract any shavings or cuttings. Finally, the inductive phenomena utilized is not sensitive to engagement with a coolant.
  • FIG. 1 illustrates somewhat schematically the basic arrangement of a roll gap control apparatus improved in accordance with the present invention
  • FIG. 2 illustrates the measuring and pick-up instrumentality employed in the arrangement of FIG. 1;
  • FIG. 3 illustrates somewhat schematically a circuit diagram of the entire roll gap control loop.
  • FIG. 1 illustrates, as stated, somewhat schematically the basic arrangement for roll gap control.
  • a journal 11 extends axially from a lower roll 10 and carries a support ring 13 for a pick-up means carrier 12.
  • the rolling mill includes an upper roll 14, and the material 16 to be rolled, i.e., the stock is disposed in the gap 19 between rolls l0 and 14.
  • the upper roll 14 has likewise a journal 15 carrying a ring 18 upon which is placed a second carrier 17 constituting measuring plate.
  • the measuring instrumentation and pick-up means are included in carrier 12 as will be described more fully below. Suffice it to say presently that an output cable means 12a provides electrical signal which represents the width of roll gap 19.
  • a control circuit 20 receives in addition a reference signal representing the desired value for the gap and being developed by an appropriate signal source 21.
  • the control circuit 20, includes amplifier means and provides an output used to control an electrohydraulical servo valve 22. Valve 22 governs an hydraulic actuation 23 which detennines and adjusts the pressure exerted upon rolls l and 14 for adjustment of the roll gap.
  • the pick-up device 12 is shown in greater details in FIG. 2 and particularly its cooperation with the measuring plate 17 is shown with particularity.
  • the pick-up means 12 includes a pair of coils 30 connected in series and being wound upon the two legs'33 of a U-shaped core 32 to establish a pick-up inductance.
  • the two legs 33 respectively have front faces that are oriented coplanar to each other and transverse to the plane of the U of core 32, whereby particularly these two front faces of legs 33 define a datum plane 34.
  • the second carrier 17 of the pick-up system is positioned adjacent to the datum plane 34 and defines particularly a second measuring plane 36 that is parallel to plane 34.
  • Carrier 17 is provided particularly for the support and positioning of an armature 35 extending lengthwise to plane 36, and the one side of armature 35 facing the legs 33 of core 32 is in that plane 36.
  • Plane 36 may also define the lower surface of measuring plate 17 as a whole.
  • the two planes 34 and 36 are spaced apart by a gap 37. The entire equipment is adjusted so that distance between planes 34 and 36 corresponds to the distance or gap width of the rolls across gap 19. Therefore, the roll gap is represented by the distance between the core 32 and armature 35, establishing a variable air gap for the pick up inductance.
  • the pick-up means includes further an auxiliary inductance 31 which includes a pair of coils connected in series and wound upon the legs of a U-shaped core 38.
  • the auxiliary inductance includes likewise an armature 39, and the two legs of core 38 have front faces facing armature 39. There is an air gap between core and armature which is adjusted to obtain a fixed spatial relationship.
  • the auxiliary inductance 31 is completely embedded in shielding 40 made of material of a high magnetic permeability.
  • core 32 is embedded in a shield 42 of similar material but being open in plane 34.
  • Armature 35 is lined by shielding 41 of material of high magnetic permeability but the shield is open in plane 36.
  • the air gap between armature 35 and core 32 is not lined with shielding.
  • the inductance as established by two serially interconnected coils 30 on legs 33 is connected in series with the auxiliary inductance 31'.
  • the common junction provides and is connected to a measuring outlet line 26.
  • the respective two other ends of inductances 30 and 31 lead to two additional connecting lines 25 and 27, provided for applying voltage across the two serially connected inductance systems. Accordingly, there are three connecting lines for this particular pick-up arrangement.
  • FIG. 3 illustrates a circuit in which the several coils appear asinductances 30 and 31 and wherein particularly inductance 30 represents the principal source for measuring input signal.
  • the series circuit connection of inductances 30 and 31 is likewise depicted in FIG. 3, and it can be seen that the two inductances form two branches of a bridge circuit.
  • Two inductances 50 and 51 are connected in series to each other,
  • Inductance 50 is variable to provide and to establish reference signal in representation of a desired value for the roll gap.
  • Inductance 51 is the second auxiliary induction in the system.
  • inductance 50 may include a core with an armature, and the armature is adjustably positioned to vary the air gap in that inductance. For example, the air gap is adjusted by means of a micrometer screw to assume the same value that is desired for the roll gap.
  • Inductances 31 and 51 may also be similar. This similarity is appropriate to obtain complete electric symmetry in the bridge circuit.
  • Inductances 50 and 51 can be regarded as representing the reference means, summarily denoted by numeral 21 in FIG. 1.
  • the reference inductance 50 and the auxiliary inductance 51 are particularly connected to inductances 30 and 31 in that the one end of auxiliary inductance 51 connects to one end of auxiliary inductance 31 to form a bridge terminal or junction A.
  • the one end of inductance 50 connects to one end of inductance 30 to form another bridge terminal or junction B.
  • the two terminal A and B are connected to a biasing source, AC generator 55.
  • the voltage drop across inductance 30 can be regarded as signal representing the actual value for the gap, while the voltage drop across inductance 50 constitutesthe reference signal.
  • inductances 50 and 51 constitutes a third bridge terminal D and is grounded.
  • the bridge output signal can, therefor, be taken from the fourth bridge terminal C, with reference to ground.
  • Terminal C is, of course, the connecting junction of inductances 30 and 31.
  • Resistances RCU are included in the bridge circuit, merely to represent ohmic losses of the respective inductances. However, during operation the bridge is presumed to remain balanced as to ohmic losses. Trimming resistors may be included in the circuit if necessary to obtain balance between ohmic losses and inductance drops.
  • a phase detector or phase sensitive rectifier 56 has one input of a first pair of AC input terminal connected to ground (i.e. to bridge terminal D), while the second AC input of the first pair is connected to bridge terminal C which is actually line 26 as leading from the junction of inductances 30 and 31.
  • the phase dependent rectifier 56 has a second pair of AC input terminal connected to generator 55.
  • the output of rectifier 56 represents the phase difference between the bridge bias voltage and the bridge voltage as derived from across diagonal C-D, and this phase difference, in turn, is a representation of the differences in efiective inductance of the inductances 30 and 50.
  • phase dependent rectifier 56 is passed through a filter 57 to eliminate AC components and is fed to a control amplifier 59.
  • Amplifier 59 controls the servo valve 22 which, in turn, and as was outlined above, controls hydraulic means 23 for adjusting pressure upon the lower roll 10.
  • the gap between rolls l0 and 14 is changed which, in turn, reflects upon the inductance 30 for closing the control loop.
  • the dashed line between elements 22 and 30 shows the actuation path of the feedback loop.
  • Control amplifier 59 is additionally connected to'a potentiometer 58 having its tap connected to the micrometer spindle by means of which inductance 50 is adjusted.
  • the adjustable resistor 58 is included in the amplifier circuit to determine the gain of the amplifier. Thus, the amplifier gain is made dependent upon the adjusted reference value forthe gap.
  • All four inductances of the system in the bridge circuit are rated, and are particularly constructed, so that they have. similar inductivity for similar air gaps.
  • the measuring inductance 30 and the auxiliary inductance 31 are combined to form a measuring pick-up means, and the reference inductance 50 may be disposed in relation to auxiliary inductance 51 to form a structurally combined reference means. Due to physical association of inductances that connect serially across the supply source 55, the bridge is rendered independent from temperature variations that affect serially connected inductances similarily. Temperature variations afiect particularly loss resistances R in the respective inductances.
  • the measuring equipment is employed, for example, in a hot rolling mill, temperature variations that the equipment may have to experience can be expected to be quite large. Severe thermal imbalance can be compensated by embedding resistors with negative temperature coefficients in the coils of the several inductances. As these resistors are also included in the bridge circuit, temperature compensation is obtained, that is effective particularly for large scale temperature variations, requiring very little additional equipment. As the bridge circuit is symmetrically constructed and connected even significant temperature variations hardly affect accuracy of measurement.
  • Generator 55 supplies the bridge with AC having a frequency selected so that WL/RCU for any of the individual inductances is quite large.
  • the frequency should not be so high that eddy current losses in the cores of the several inductances or changes in capacity of the connecting lines exert any significant influence upon the accuracy of measurement.
  • control amplifier 59 receives information from the bridge circuit via phase dependent phase rectifier or phase detector 56 as so-called zero information, i.e., in case the reference value for the roll gap agrees with the actual value thereof.
  • additional off-set means may be included in the input circuit for amplifier 59.
  • Amplifier 59 receives zero input.
  • This mode of developing control signals for the regulation eliminates the requirement for the usual constant current or constant voltage sources which, if needed in the present case, would require considerable expenditure due to requirement of high signal-to-noise ratio.
  • the high permeability shields of the several inductances eliminate external stay field and improve the signal-to-noise ratio further.
  • the control circuit includes amplifying circuitry 59 that is operated in accordance with the principles of operational amplifiers, in which the desired response is obtained through adjustment by means of an external network. Additional input signals for control and regulator amplifier circuit 59 may be combined with the output from filter 57, for example, in accordance with the principle of error feed forward operation.
  • potentiometer 58 is ganged with the micrometer spindle for adjusting the reference value in inductance 50, and this potentiometer 58 is included in the amplifier circuit. This way the loop gain of the control and regulating loop is maintained constant and, therefore, optimizes transient response behavior of the system to be independent from the adjusted reference value for the roll gap. This compensation of loop gain is necessary as the measuring in ductance varies hyperbolically with width of gap 37, and the voltage gradient across the bridge decreases with increasing in the air gap.
  • the carrier 12 for the pick-up means is by itself constructed of ferromagnetic material to provide magnetic shielding directly.
  • the measuring plate 17 can be constructed from ferromagnetic material obviating in this case the particular shield 41.
  • Apparatus for control of the gap between a pair of rolls in a mill, the rolls of the pair having journals comprising:
  • first means defining a pick-up inductance m the first carrier ductance of the first means corresponding to the gap width between the rolls;
  • third means including first and second reference inductance means, at least one thereof being adjustable, bothof them being connected to the inductance of the first and second means to define a bridge circuit;
  • fourth means including a source of AC potential connected to electrically energizing the bridge circuit;
  • control means connected to be operated in response to the control signal to adjust the gap of the rolls so as to complete a control loop.
  • the inductances of the first, second and third means each having an air gap, the air gap of the auxiliary inductance and of the first and second reference inductance means being selected and adjusted to remain constant, the air gap of at least one of the reference inductance means adjustable to obtain reference value adjustment, there being means for adjusting the air gap of the one reference inductance means, the inductances having equal inductivity for similarly adjusted air gaps.
  • the AC voltage having frequency so that the inductivity vs ohmic loss ratio of either inductance is relatively larger at still low eddy current losses in the respective cores and relatively low capacitive losses.
  • the fifths means including a phase sensitive rectifier connected to receive the AC voltage as provided by the fourth means and further connected to receive a bridge voltage as derived from the junctions to provide the control voltage, the control voltage being zero when the roll gap agrees with the reference gap, the fifths means including a filter to eliminate the a.c. component from the control voltage.
  • control means including an operational amplifier, the one reference inductance having adjusting means coupled to the operational amplifier to vary the gain thereof to maintain the loop gain of the control loop.
  • the operational amplifier having means to adjust its response.
  • the first and second carriers made of non-magnetic material, the inductances in the first carrier and the armature in the second carrier being shielded by means of material having high magnetic permeability.
  • the first and second carriers made of ferromagnetic material to serve as magnetic shields.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Control Of Metal Rolling (AREA)
US28351A 1969-06-21 1970-04-13 Control for roll gap of a rolling mill Expired - Lifetime US3662576A (en)

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DE19691931654 DE1931654B2 (de) 1969-06-21 1969-06-21 Walzenspaltpositionsregelung fuer walzgerueste

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US (1) US3662576A (enrdf_load_stackoverflow)
DE (1) DE1931654B2 (enrdf_load_stackoverflow)
FR (1) FR2052831A5 (enrdf_load_stackoverflow)
GB (1) GB1288481A (enrdf_load_stackoverflow)
SE (1) SE353792B (enrdf_load_stackoverflow)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3777526A (en) * 1971-03-17 1973-12-11 Krupp Gmbh Roller gap control
US3817068A (en) * 1972-05-20 1974-06-18 F Meyer Roll gap and gap error monitoring device
US3849724A (en) * 1971-11-17 1974-11-19 Krauss Maffei Ag Method and apparatus for measuring the gap spacing and relative transverse displacement of an electromagnetic core from an armature using magnetic field sensors
US3850015A (en) * 1972-05-20 1974-11-26 Ver Flugtechnische Werke Roll gap detection
US3902114A (en) * 1967-10-20 1975-08-26 Gunther Alich Method of and apparatus for measuring the distance between cooperating rollers of a rolling mill
US4400665A (en) * 1978-12-23 1983-08-23 Norbert Nix Device for automatically measuring thickness of coatings on a substrate by comparison with an uncoated substrate
US4459550A (en) * 1980-05-22 1984-07-10 Nix Maria Non-magnetic layer thickness tester utilizing a permanent magnet
US4661774A (en) * 1983-12-12 1987-04-28 Harris Graphics Corporation Method and apparatus for monitoring film thickness between rotatable rolls
US4767987A (en) * 1983-12-12 1988-08-30 Harris Graphics Corporation Method and apparatus for monitoring film thicknesses by sensing magnetic interaction between members movable to a film thickness distance
US4814703A (en) * 1987-08-04 1989-03-21 The Boeing Company Method and apparatus for gap measurement between a graphite/epoxy structure and a metallic model
US5040272A (en) * 1989-02-16 1991-08-20 Rieter Machine Works Limited Spacing sensor arrangement and method of checking the spacing between a main carding cylinder and carding machine parts
US5089776A (en) * 1989-09-25 1992-02-18 Nkk Corporation Apparatus for detecting defects in a moving steel strip with a magnetizing yoke and a sensor placed on opposite sides of the strip
US5155444A (en) * 1991-08-22 1992-10-13 Xerox Corporation Trim bar gap verification tool and method using a flexible capacitor sensor having a magnetic metallic laminate
US5177446A (en) * 1989-07-05 1993-01-05 G. D. Societa Per Azioni Device for monitoring the depletion of material uncoiling from rolls, applicable in particular to wrapping machines
US5235275A (en) * 1990-02-22 1993-08-10 Nkk Corporation Magnetic inspection apparatus for thin steel strip having magnetizer and detection coil within a hollow roller rotated by the steel strip
US5617024A (en) * 1993-10-12 1997-04-01 The United States Of America As Represented By The United States National Aeronautics And Space Administration Flux focusing eddy current probe
EP0732599A3 (en) * 1995-03-17 1997-11-26 Radiodetection Limited Inductive transmitters for conductor location
US6366082B1 (en) * 1998-02-26 2002-04-02 Metso Paper Automation Oy Method and apparatus for determining properties of a moving web with a differential coil sensor
JP2019510643A (ja) * 2016-03-08 2019-04-18 ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． プロセスパラメータの直接測定を用いて転造中の金属ストリッププロファイルを制御するための方法および装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2228336C2 (de) * 1972-06-10 1983-04-14 Vereinigte Flugtechnische Werke Gmbh, 2800 Bremen Anordnung zur Messung des Spaltes eines Arbeitswalzenpaares
JPS563149B2 (enrdf_load_stackoverflow) * 1973-06-11 1981-01-23
DE2404763C2 (de) * 1974-02-01 1982-05-13 Vereinigte Flugtechnische Werke Gmbh, 2800 Bremen Meßvorrichtung zur Erfassung des Spaltes eines Arbeitswalzenpaares
GB1529861A (en) * 1975-01-14 1978-10-25 Loewy Robertson Eng Co Ltd Roll gap measurement
JP2626942B2 (ja) * 1992-02-21 1997-07-02 株式会社ブリヂストン カレンダー加工におけるシート厚さの制御方法および制御装置

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US2711510A (en) * 1950-06-21 1955-06-21 Rca Corp Metal detector balance controls
US2934698A (en) * 1956-12-03 1960-04-26 Honeywell Regulator Co Magnetic control apparatus
US3208251A (en) * 1961-05-03 1965-09-28 Westinghouse Canada Ltd Rolling mill control system
US3389588A (en) * 1965-03-09 1968-06-25 United States Steel Corp Apparatus for controlling the position of work rolls
US3441840A (en) * 1967-03-31 1969-04-29 Martin Marietta Corp Electronic thickness meter having direct readout of coating thickness
US3492845A (en) * 1966-12-30 1970-02-03 Shibaura Kyodo Kogyo Kk Rolling mill control system
US3516273A (en) * 1966-08-16 1970-06-23 United Eng Foundry Co Strip thickness measuring device for use in a rolling mill and like apparatus

Patent Citations (7)

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Publication number Priority date Publication date Assignee Title
US2711510A (en) * 1950-06-21 1955-06-21 Rca Corp Metal detector balance controls
US2934698A (en) * 1956-12-03 1960-04-26 Honeywell Regulator Co Magnetic control apparatus
US3208251A (en) * 1961-05-03 1965-09-28 Westinghouse Canada Ltd Rolling mill control system
US3389588A (en) * 1965-03-09 1968-06-25 United States Steel Corp Apparatus for controlling the position of work rolls
US3516273A (en) * 1966-08-16 1970-06-23 United Eng Foundry Co Strip thickness measuring device for use in a rolling mill and like apparatus
US3492845A (en) * 1966-12-30 1970-02-03 Shibaura Kyodo Kogyo Kk Rolling mill control system
US3441840A (en) * 1967-03-31 1969-04-29 Martin Marietta Corp Electronic thickness meter having direct readout of coating thickness

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902114A (en) * 1967-10-20 1975-08-26 Gunther Alich Method of and apparatus for measuring the distance between cooperating rollers of a rolling mill
US3777526A (en) * 1971-03-17 1973-12-11 Krupp Gmbh Roller gap control
US3849724A (en) * 1971-11-17 1974-11-19 Krauss Maffei Ag Method and apparatus for measuring the gap spacing and relative transverse displacement of an electromagnetic core from an armature using magnetic field sensors
US3817068A (en) * 1972-05-20 1974-06-18 F Meyer Roll gap and gap error monitoring device
US3850015A (en) * 1972-05-20 1974-11-26 Ver Flugtechnische Werke Roll gap detection
US4400665A (en) * 1978-12-23 1983-08-23 Norbert Nix Device for automatically measuring thickness of coatings on a substrate by comparison with an uncoated substrate
US4459550A (en) * 1980-05-22 1984-07-10 Nix Maria Non-magnetic layer thickness tester utilizing a permanent magnet
US4661774A (en) * 1983-12-12 1987-04-28 Harris Graphics Corporation Method and apparatus for monitoring film thickness between rotatable rolls
US4767987A (en) * 1983-12-12 1988-08-30 Harris Graphics Corporation Method and apparatus for monitoring film thicknesses by sensing magnetic interaction between members movable to a film thickness distance
US4814703A (en) * 1987-08-04 1989-03-21 The Boeing Company Method and apparatus for gap measurement between a graphite/epoxy structure and a metallic model
US5040272A (en) * 1989-02-16 1991-08-20 Rieter Machine Works Limited Spacing sensor arrangement and method of checking the spacing between a main carding cylinder and carding machine parts
US5177446A (en) * 1989-07-05 1993-01-05 G. D. Societa Per Azioni Device for monitoring the depletion of material uncoiling from rolls, applicable in particular to wrapping machines
US5089776A (en) * 1989-09-25 1992-02-18 Nkk Corporation Apparatus for detecting defects in a moving steel strip with a magnetizing yoke and a sensor placed on opposite sides of the strip
US5235275A (en) * 1990-02-22 1993-08-10 Nkk Corporation Magnetic inspection apparatus for thin steel strip having magnetizer and detection coil within a hollow roller rotated by the steel strip
US5155444A (en) * 1991-08-22 1992-10-13 Xerox Corporation Trim bar gap verification tool and method using a flexible capacitor sensor having a magnetic metallic laminate
US5617024A (en) * 1993-10-12 1997-04-01 The United States Of America As Represented By The United States National Aeronautics And Space Administration Flux focusing eddy current probe
EP0732599A3 (en) * 1995-03-17 1997-11-26 Radiodetection Limited Inductive transmitters for conductor location
US5764127A (en) * 1995-03-17 1998-06-09 Radiodetection Limited Inductive transmitters for conductor location
US6366082B1 (en) * 1998-02-26 2002-04-02 Metso Paper Automation Oy Method and apparatus for determining properties of a moving web with a differential coil sensor
JP2019510643A (ja) * 2016-03-08 2019-04-18 ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． プロセスパラメータの直接測定を用いて転造中の金属ストリッププロファイルを制御するための方法および装置
US10994317B2 (en) * 2016-03-08 2021-05-04 Novelis Inc. Method and apparatus for controlling metal strip profile during rolling with direct measurement of process parameters
US11858022B2 (en) 2016-03-08 2024-01-02 Novelis Inc. Method and apparatus for controlling metal strip profile during rolling with direct measurement of process parameters

Also Published As

Publication number Publication date
FR2052831A5 (enrdf_load_stackoverflow) 1971-04-09
SE353792B (enrdf_load_stackoverflow) 1973-02-12
GB1288481A (enrdf_load_stackoverflow) 1972-09-13
DE1931654A1 (de) 1971-05-27
DE1931654B2 (de) 1971-11-11

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