EP0045470B1 - Method and apparatus for bending a long metal object - Google Patents

Method and apparatus for bending a long metal object Download PDF

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Publication number
EP0045470B1
EP0045470B1 EP81105933A EP81105933A EP0045470B1 EP 0045470 B1 EP0045470 B1 EP 0045470B1 EP 81105933 A EP81105933 A EP 81105933A EP 81105933 A EP81105933 A EP 81105933A EP 0045470 B1 EP0045470 B1 EP 0045470B1
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EP
European Patent Office
Prior art keywords
temperature
heated zone
sensors
zone
bending
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81105933A
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German (de)
French (fr)
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EP0045470A1 (en
Inventor
Jacques Nicolas
Paul Lenglet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stein Industrie SA
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Stein Industrie SA
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Publication date
Priority claimed from FR8017297A external-priority patent/FR2488162B1/en
Priority claimed from FR8100539A external-priority patent/FR2497697A2/en
Application filed by Stein Industrie SA filed Critical Stein Industrie SA
Publication of EP0045470A1 publication Critical patent/EP0045470A1/en
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Publication of EP0045470B1 publication Critical patent/EP0045470B1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/16—Auxiliary equipment, e.g. for heating or cooling of bends
    • B21D7/162—Heating equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
    • B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
    • B21D7/025—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and pulling or pushing the ends of the work

Definitions

  • the present invention relates to a method of bending an elongated metal element of constant cross section by heating a narrow zone around the periphery of this element using a heating collar surrounding this zone, pushed on one end of the element and maintenance of its other end by a pivoting arm, in which the temperature of the zone heated by the periphery of the element is kept substantially constant by detecting the temperature of the latter, and by increasing or decreasing the heat input at one or other of the points of said periphery of the element depending on whether the temperature there is lower or higher, to a set value corresponding to a uniform temperature around the heated zone. It applies in particular to the bending of large diameter tubes, but also to that of bars, profiles, etc. It also extends to a device for the implementation of this process.
  • the invention aims to remedy this drawback, and to provide a method and a device for bending an elongated metal element which ensures a constant temperature of the heated zone over its entire periphery as well as over time.
  • the method of the invention is characterized in that the temperature of the heated zone is detected at at least two points around the periphery of the element, one of which is on the side of the center of curvature, and the other opposite in the first, using sensors, which are made to describe a back and forth movement parallel to the axis of the element not yet bent and sweeping the width of the heated area.
  • the temperature of the heated area is detected by aiming it, on the one hand using a first set of sensors arranged upstream of the heated area and whose axis makes an acute angle with l axis of the element not yet bent, on the other hand using a second set of sensors spaced longitudinally from the first and of orientation such that it allows them to observe the part of the heated zone which can be obscured vis-à-vis the first set of sensors by the heating collar during part of the bending operation.
  • the thermal input in the detection zones is increased or decreased by providing a heating collar with constant power corresponding to the minimum temperature of deformation of the heated zone of the elongated element, and by bringing it closer or away, or modifying it the power supplied to additional heating elements arranged opposite the detection zones.
  • the invention also extends to a bending device for implementing the method defined above, comprising a heating collar surrounding the area to be heated to allow bending, means for pushing said element, and a pivoting arm for holding the other end of the element, detectors for the temperature of the heated zone, and means for increasing or decreasing the heat input at one or other of the points of the metallic element depending on whether the temperature there is higher or lower than a set value corresponding to a uniform temperature around the heated area, characterized in that the temperature sensors of the heated area are arranged at at least two points around the edge of the element, one of which is on the side of the center of the curvature, and the other on the opposite side, and in that it comprises means for alternating longitudinal displacement of the detectors enabling them to scan the width of the heated zone.
  • It includes temperature detectors connected via a multiplexing device, on the one hand to separate temperature recorders, on the other hand to a peak storage detector and to a temperature display device. maximum, as well as preferably a successive display of temperatures on the same recorder.
  • the detection means are connected to servomotors, on the one hand for the overall displacement of the heating collar, and on the other hand for deformation thereof.
  • the heating collar consists of an internal collar providing constant power corresponding to the minimum deformation temperature of the heated zone, and of additional heating elements arranged opposite the detection zones, and it furthermore comprises means for bringing together or move them away from the elongated metal element, or to modify the power supplied to them.
  • the bending tube 1 is subjected at one end by a mechanical device to a thrust represented by the arrow 2, while a movable arm 3, rotating around an axis 4, maintains the other end of the tube by a collar 5.
  • a movable arm 3 rotating around an axis 4, maintains the other end of the tube by a collar 5.
  • the heating of the zone where the deformation must occur, of an appropriate width, is ensured by an inductor collar 6, this being followed by a cooling device 7 to the air or water.
  • Figure 2 shows a section through the axis of the tube to be bent. Its wall is represented at 10.
  • the zone to be heated 11 is surrounded by the inductor 6.
  • An infrared radiation sensor 12 is arranged upstream of the heated zone relative to the inductor and inclined so as to be able to target the entire heated area without interference from the inductor.
  • a sensor is driven, by means not shown, with a back-and-forth movement represented by the double arrow 12A, so as to be able to record the temperature of the entire width of the heated zone, and in particular the maximum temperature .
  • sensors are arranged at other points around the periphery of the tube, for example three other sensors at 90 ° from one another.
  • FIG. 3 represents a temperature analysis chain using four sensors such as that of FIG. 2.
  • Each of the sensors 12, 13, 14, 15 is connected by an optical fiber 16, 17, 18, 19, to an optical amplifier 20, 21, 22, 23.
  • the four amplifiers are connected to a multiplexer 24, at terminals a, b, c, d, the multiplexing being controlled by a movable contact.
  • the multiplexer is followed by an amplifier 26, followed by a peak detector-memorizer 27.
  • the latter is connected by a linearization device 28 and an emissivity coefficient adjustment device 29, on the one hand to a digital display, on the other hand to a temperature recorder.
  • the digital maximum temperature display panel 30 is connected to a member for displaying the maximum and minimum setpoints 31, itself connected to alarm indicators 32, 33.
  • the recorder 34 successively records the four temperature readings on the same graph.
  • a comparator 40 receives the indications, on the one hand from the temperature read by a sensor (arrow 41 on the other hand from the reference temperature (arrow 42), and delivers a signal giving in amplitude and in sign the value of their difference. This signal is transmitted to an amplifier 43, then to a servomotor control 44.
  • the servomotor 45 exerts pressure or traction on an inductor with variable geometry 46. If the temperature read is lower than the temperature as a reference, it brings the inductor closer to the surface of the tube and, if it is higher, moves it away.
  • the heated area of the tube 1 is surrounded by an inductor collar 6 of shape corresponding to the theoretical shape of the tube (circular). It is surrounded by four additional inductors 61, 62, 63, 64, 90 ° apart, and with the same axes as the temperature sensors.
  • Inductor 6 is coaxial with the tube and supplied with a power such that each sensor reads the minimum deformation temperature. The temperature observed for each sensor is compared to the set temperature and the value of the difference commands an injection of electrical power into the corresponding additional inductor, or a displacement of the latter to vary its air gap.
  • the device of Figure 6 aims to remedy a difficulty resulting from the fact that, in the implementation of the method, it is necessary to move the heating collar back during the course of the operation, the heated area tending to move forward due to the progression of the metal element, the heating of which is not instantaneous.
  • the temperature of the heated zone is detected by means of temperature sensors arranged so as to form an angle relative to the axis sufficiently acute to target the heated zone under the heating collar, it has been found to be following tests that the sensors could have in their field at the end of the operation only part of the heated area, the other part being obscured by the heating collar.
  • the method corresponding to the device shown in this figure aims to remedy this drawback and to allow constant observation of the maximum temperature of the heated area around its entire periphery, and consequently an appropriate correction of the thermal inputs around the periphery of the element to be bent, and maximum reduction of defects in the shape of the bent metal element.
  • the tube 71 is pushed in the direction of the arrow.
  • the heating collar 72 is placed in the initial preheating period in position 72A, then it is moved back during the bending operation in position 72B.
  • the water spray cooling toroid initially in position 73A, is moved back with the heating collar to position 73B.
  • the infrared temperature detectors are carried by arms 74, fixed to a movable support 75.
  • the arm 74 carries two gripping grippers for the detectors, the gripper 76 carrying the detector 77, with an aiming axis making an acute angle with the axis of advancement of the tube, and the detector 79, with an aiming axis perpendicular to this same line of advancement.
  • the mobile support and the arm are moved back and forth with amplitude A L.
  • the arm 76 and the detector 77 therefore advance to positions 76A and 77A, then return to their initial positions.
  • the arm 78 and the detector 79 advance to positions 78A and 79A, then return to their initial positions.
  • the scanning field by the detectors is shown in gray in the figure (80).
  • the detector 77 scans substantially the entire heated area. When the heating collar has been moved back to position 72B, the heated area is partly obscured by the detector 77, but the rest of this area is in the field scanned by the detector 79.
  • the asymmetry of thermal contribution to the heated zone could be detected by measuring other physical properties than infrared radiation.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Radiation Pyrometers (AREA)

Description

La présente invention concerne un procédé de cintrage d'un élément métallique allongé de section droite constante par chauffage d'une zone étroite du pourtour de cet élément à l'aide d'un collier chauffant entourant cette zone, poussée sur une extrémité de l'élément et maintien de son autre extrémité par un bras pivotant, dans lequel l'on maintient sensiblement constante la température de la zone chauffée par le pourtour de l'élément en détectant la température de cette dernière, et en augmentant ou diminuant l'apport thermique en l'un ou l'autre des points dudit pourtour de l'élément suivant que la température y est inférieure ou supérieure, à une valeur de consigne correspondant à une température uniform du pourtour de la zone chauffée. Elle s'applique notamment au cintrage de tubes de gros diamètre, mais également à celui de barres, de profilés, etc.. Elle s'étend en outre à un dispositif pour la mise en oeuvre de ce procédé.The present invention relates to a method of bending an elongated metal element of constant cross section by heating a narrow zone around the periphery of this element using a heating collar surrounding this zone, pushed on one end of the element and maintenance of its other end by a pivoting arm, in which the temperature of the zone heated by the periphery of the element is kept substantially constant by detecting the temperature of the latter, and by increasing or decreasing the heat input at one or other of the points of said periphery of the element depending on whether the temperature there is lower or higher, to a set value corresponding to a uniform temperature around the heated zone. It applies in particular to the bending of large diameter tubes, but also to that of bars, profiles, etc. It also extends to a device for the implementation of this process.

Dans un procédé de ce genre, tel que proposé par le document US-A-3 902 344, il est difficile d'assurer une température uniforme dans la zone chauffée, et la température que l'on détecte en visant celle-ci peut être différente de la température maximale, ce que amène à des corrections de l'apport thermique différentes de celles qui seraient nécessaires, ce qui entraîne des variations de cette température, tant sur le pourtour de l'élément que dans le temps.In a process of this kind, as proposed by document US-A-3,902,344, it is difficult to ensure a uniform temperature in the heated zone, and the temperature which is detected by targeting it can be different from the maximum temperature, which leads to corrections of the thermal input different from those which would be necessary, which leads to variations of this temperature, both around the element and over time.

L'invention a pour but remédier à cet inconvénient, et de procurer un procédé et un dispositif de cintrage d'un élément métallique allongé qui assure une tempéature de la zone chauffée constante sur tout son pourtour ainsi que dans le temps.The invention aims to remedy this drawback, and to provide a method and a device for bending an elongated metal element which ensures a constant temperature of the heated zone over its entire periphery as well as over time.

Le procédé de l'invention est caractérisé en ce que l'on détecte la température de la zone chauffée en au moins deux points du pourtour de l'élément, dont l'un est du côté du centre de courbure, et l'autre opposé au premier, à l'aide de capteurs, à qui l'on fait décrire un mouvement de va-et-vient parallèle à l'axe de l'élément non encore cintré et balayant la largeur de la zone chauffée.The method of the invention is characterized in that the temperature of the heated zone is detected at at least two points around the periphery of the element, one of which is on the side of the center of curvature, and the other opposite in the first, using sensors, which are made to describe a back and forth movement parallel to the axis of the element not yet bent and sweeping the width of the heated area.

Il répond en outre de préférence à au moins l'une des caractéristiques suivantes:

  • L'on mesure la température de la zone chauffée en quatre points à 90° l'un de l'autre.
It also preferably meets at least one of the following characteristics:
  • The temperature of the heated area is measured at four points 90 ° apart.

L'on détecte la température de la zone chauffée par visée de celle-ci, d'une part à l'aide d'un premier jeu de capteurs disposés en amont de la zone chauffée et dont l'axe fait un angle aigu avec l'axe de l'élément non encore cintré, d'autre part à l'aide d'un second jeu de capteurs espacés longitudinalement des premiers et d'orientation telle qu'elle leur permet d'observer la partie de la zone chauffée qui peut être occultée vis-à-vis du premier jeu de capteurs par le collier chauffant pendant une partie de l'opération de cintrage.The temperature of the heated area is detected by aiming it, on the one hand using a first set of sensors arranged upstream of the heated area and whose axis makes an acute angle with l axis of the element not yet bent, on the other hand using a second set of sensors spaced longitudinally from the first and of orientation such that it allows them to observe the part of the heated zone which can be obscured vis-à-vis the first set of sensors by the heating collar during part of the bending operation.

L'on augmente ou diminue l'apport thermique dans les zones de détection en fournissant à un collier chauffant une puissance constante correspondant à la température minimale de déformation de la zone chauffée de l'élément allongé, et en rapprochant ou éloignant, ou du modifiant la puissance fournie à des éléments chauffants additionnels disposés en face des zones de détection.The thermal input in the detection zones is increased or decreased by providing a heating collar with constant power corresponding to the minimum temperature of deformation of the heated zone of the elongated element, and by bringing it closer or away, or modifying it the power supplied to additional heating elements arranged opposite the detection zones.

L'invention s'étend d'autre part à un dispositif de cintrage pour la mise en oeuvre du procédé défini ci-dessus, comprenant un collier chauffant entourant la zone à chauffer pour permettre le cintrage, des moyens pour pousser ledit élément, et un bras pivotant de maintien de l'autre extrémité de l'élément, des détecteurs de la température de la zone chauffée, et des moyens pour augmenter ou diminuer l'apport thermique en l'un ou l'autre des points de l'élément métallique suivant que la température y est supérieure ou inférieure à une valeur de consigne correspondant à une température uniforme du pourtour de la zone chauffée, caractérisé en ce que les détecteurs de la température de la zone chauffée sont disposés en au moins deux points du pourtour de l'élément, dont l'un est du côté du centre du courbure, et l'autre du côté opposé, et en ce qu'il comprend des moyens de déplacement longitudinal alternatif des détecteurs leur permettant de balayer la largeur de la zone chauffée.The invention also extends to a bending device for implementing the method defined above, comprising a heating collar surrounding the area to be heated to allow bending, means for pushing said element, and a pivoting arm for holding the other end of the element, detectors for the temperature of the heated zone, and means for increasing or decreasing the heat input at one or other of the points of the metallic element depending on whether the temperature there is higher or lower than a set value corresponding to a uniform temperature around the heated area, characterized in that the temperature sensors of the heated area are arranged at at least two points around the edge of the element, one of which is on the side of the center of the curvature, and the other on the opposite side, and in that it comprises means for alternating longitudinal displacement of the detectors enabling them to scan the width of the heated zone.

Ce dispositif répond de préférence à au moins l'une des caractéristiques suivantes:

  • Il comprend quatre détecteurs de température à infra-rouge à 90° l'un de l'autre.
This device preferably meets at least one of the following characteristics:
  • It includes four infrared temperature detectors at 90 ° to each other.

Il comprend des détecteurs de température reliés par l'intermédiaire d'un dispositif de multiplexage, d'une part à des enregistreurs de température distincts, d'autre part à un détecteur de mémorisation de crête et à un dispositif d'affichage de la température maximale, ainsi que de préférence à un dispositif d'affichage successif des températures sur le même enregistreur.It includes temperature detectors connected via a multiplexing device, on the one hand to separate temperature recorders, on the other hand to a peak storage detector and to a temperature display device. maximum, as well as preferably a successive display of temperatures on the same recorder.

Les moyens de détections sont reliés à des servomoteurs, d'une part de déplacement global du collier chauffant, d'autre part de déformation de celui-ci.The detection means are connected to servomotors, on the one hand for the overall displacement of the heating collar, and on the other hand for deformation thereof.

Le collier chauffant se compose d'un collier interne fournissant une puissance constante correspondant à la température minimale de déformation de la zone chauffée, et d'éléments chauffants additionnels disposés en face des zones de détection, et il comporte en outre des moyens pour rapprocher ou éloigner ceux-ci de l'élément métallique allongé, ou pour modifier la puissance qui leur est fournie.The heating collar consists of an internal collar providing constant power corresponding to the minimum deformation temperature of the heated zone, and of additional heating elements arranged opposite the detection zones, and it furthermore comprises means for bringing together or move them away from the elongated metal element, or to modify the power supplied to them.

Il est décrit ci-après, à titre d'exemples et en référence aux figures du dessin annexé, des dispositifs capteurs de la température de la zone chauffée d'un tube en cours de cintrage, et de réglage du chauffage de façon à maintenir cette température sensiblement constante sur tout le pourtour.

  • La figure 1 représente schématiquement un dispositif selon l'invention de cintrage de tube de grand diamètre.
  • La figure 2 représente la position et le déplacement d'un capteur de mesure de la température.
  • La figure 3 représente une chaîne d'analyse des températures en quatre points à 90° du pourtour d'un tube employée dans le dispositif selon la figure 1.
  • La figure 4 représente schématiquement un dispositif de réglage de l'inducteur en fonction de la température lue par un capteur.
  • La figure 5 représente la disposition d'un inducteur à collier interne et à inducteurs additionnels mobiles ou à puissance réglable.
  • La figure 6 représente un dispositif de cintrage à deux jeux de capteurs espacés longitudinalement l'un de l'autre.
It is described below, by way of examples and with reference to the figures of the appended drawing, devices for sensing the temperature of the heated area of a tube during bending, and for adjusting the heating so as to maintain this temperature substantially constant all around.
  • FIG. 1 schematically represents a device according to the invention for bending a large diameter tube.
  • FIG. 2 represents the position and the displacement of a temperature measurement sensor.
  • Figure 3 represents a chain of analysis of temperatures at four points at 90 ° from the periphery of a tube used in the device according to FIG. 1.
  • FIG. 4 schematically represents a device for adjusting the inductor as a function of the temperature read by a sensor.
  • FIG. 5 represents the arrangement of an inductor with an internal collar and additional inductors which are mobile or with adjustable power.
  • FIG. 6 represents a bending device with two sets of sensors spaced longitudinally from one another.

Dans le dispositif de la figure 1, le tube à cintrer 1 est soumis à une extrémité par un dispositif mécanique à une poussée représentée par le flèche 2, cependant qu'un bras mobile 3, rotatif autour d'un axe 4, maintient l'autre extrémité du tube par un collier 5. Le chauffage de la zone où doit se produire la déformation, d'une largeur appropriée, est assuré par un collier inducteur 6, celui-ci étant suivi d'un dispositif de refroidissement 7 à l'air ou à l'eau.In the device of FIG. 1, the bending tube 1 is subjected at one end by a mechanical device to a thrust represented by the arrow 2, while a movable arm 3, rotating around an axis 4, maintains the other end of the tube by a collar 5. The heating of the zone where the deformation must occur, of an appropriate width, is ensured by an inductor collar 6, this being followed by a cooling device 7 to the air or water.

La figure 2 représente une coupe par l'axe du tube à cintrer. Sa paroi est représentée en 10. La zone à chauffer 11 est entourée par l'inducteur 6. Un capteur à rayonnement infra-rouge 12 est disposé en amont de la zone chauffée par rapport à l'inducteur et incliné de façon à pouvoir viser la totalité de la zone chauffée sans interférence de l'inducteur. Un capteur est animé, par des moyens non représentés, d'un mouvement de va-et-vient représenté par la double flèche 12A, de façon à pouvoir enregistrer la température de toute la largeur de la zone chauffée, et en particulier la température maximale.Figure 2 shows a section through the axis of the tube to be bent. Its wall is represented at 10. The zone to be heated 11 is surrounded by the inductor 6. An infrared radiation sensor 12 is arranged upstream of the heated zone relative to the inductor and inclined so as to be able to target the entire heated area without interference from the inductor. A sensor is driven, by means not shown, with a back-and-forth movement represented by the double arrow 12A, so as to be able to record the temperature of the entire width of the heated zone, and in particular the maximum temperature .

Bien entendu, d'autres capteurs sont disposés en d'autres points du pourtour du tube, par exemple trois autres capteurs à 90° l'un de l'autre.Of course, other sensors are arranged at other points around the periphery of the tube, for example three other sensors at 90 ° from one another.

La figure 3 représente une chaîne d'analyse des températures à l'aide de quatre capteurs tels que celui de la figure 2. Chacun des capteurs 12, 13, 14, 15 est relié par une fibre optique 16, 17, 18, 19, à un amplificateur optique 20, 21, 22, 23. Les quatre amplificateurs sont reliés à un multi- plexeur 24, à bornes a, b, c, d, le multiplexage étant commandé par un contact mobile. Le multi- plexeur est suivi d'un amplificateur 26, suivi d'un détecteur-mémorisateur de crête 27. Ce dernier est relié par un organe de linéarisation 28 et un organe de réglage du coefficient d'émissivité 29, d'une part à un affichage digital, d'autre part à un enregistreur des températures.FIG. 3 represents a temperature analysis chain using four sensors such as that of FIG. 2. Each of the sensors 12, 13, 14, 15 is connected by an optical fiber 16, 17, 18, 19, to an optical amplifier 20, 21, 22, 23. The four amplifiers are connected to a multiplexer 24, at terminals a, b, c, d, the multiplexing being controlled by a movable contact. The multiplexer is followed by an amplifier 26, followed by a peak detector-memorizer 27. The latter is connected by a linearization device 28 and an emissivity coefficient adjustment device 29, on the one hand to a digital display, on the other hand to a temperature recorder.

Le tableau d'affichage digital de la température maximale 30 est relié à un organe d'affichage des valeurs de consigne maximale et minimale 31, lui-même connecté à des voyants d'alarme 32, 33. L'enregistreur 34 enregistre successivement les quatre lectures de température sur le même graphique.The digital maximum temperature display panel 30 is connected to a member for displaying the maximum and minimum setpoints 31, itself connected to alarm indicators 32, 33. The recorder 34 successively records the four temperature readings on the same graph.

Par ailleurs, des enregistreurs distincts 35, 36, 37, 38, reliés au contact mobile 25, affichent les variations de la température observée par chacun des capteurs.Furthermore, separate recorders 35, 36, 37, 38, connected to the movable contact 25, display the variations in temperature observed by each of the sensors.

Dans la figure 4, un comparateur 40 reçoit les indications, d'une part de la température lue par un capteur (flèche 41 d'autre part de la température de référence (flèche 42), et délivre un signal donnant en amplitude et en signe la valeur de leur différence. Ce signal est transmis à un amplificateur 43, puis à une commande 44 de servomoteur 45. Le servomoteur 45 exerce une pression ou une traction sur un inducteur à géométrie variable 46. Si la température lue est inférieure à la température de référence, il rapproche l'inducteur de la surface du tube. Si elle lui est supérieure, il l'en écarte.In FIG. 4, a comparator 40 receives the indications, on the one hand from the temperature read by a sensor (arrow 41 on the other hand from the reference temperature (arrow 42), and delivers a signal giving in amplitude and in sign the value of their difference. This signal is transmitted to an amplifier 43, then to a servomotor control 44. The servomotor 45 exerts pressure or traction on an inductor with variable geometry 46. If the temperature read is lower than the temperature as a reference, it brings the inductor closer to the surface of the tube and, if it is higher, moves it away.

Dans la figure 5, la zone chauffée du tube 1 est entourée d'un collier inducteur 6 de forme correspondant à la forme théorique du tube (circulaire). Il est entouré de quatre inducteurs additionnels 61, 62, 63, 64, à 90° l'un de l'autre, et de mêmes axes que les capteurs de température. L'inducteur 6 est coaxial au tube et alimenté sous une puissance telle que chaque capteur lise la température minimale de déformation. La température observée pour chaque capteur est comparée à la température de consigne et la valeur de la différence commande une injection de puissance électrique dans l'inducteur additionnel correspondant, ou un déplacement de celui-ci pour faire varier son entrefer.In Figure 5, the heated area of the tube 1 is surrounded by an inductor collar 6 of shape corresponding to the theoretical shape of the tube (circular). It is surrounded by four additional inductors 61, 62, 63, 64, 90 ° apart, and with the same axes as the temperature sensors. Inductor 6 is coaxial with the tube and supplied with a power such that each sensor reads the minimum deformation temperature. The temperature observed for each sensor is compared to the set temperature and the value of the difference commands an injection of electrical power into the corresponding additional inductor, or a displacement of the latter to vary its air gap.

Le dispositif de la figure 6 vise à remédier à une difficulté résultant du fait que, dans la mise en oeuvre du procédé, l'on est amené à reculer le collier chauffant pendant le cours de l'opération, la zone chauffée tendant à se déplacer vers l'avant en raison de la progression de l'élément métallique dont l'échauffement n'est pas instantané. Lorsque l'on détecte la température de la zone chauffée à l'aide de capteurs de température disposés de façon à former un angle par rapport à l'axe suffisamment aigu pour viser la zone chauffée sous le collier chauffant, il s'est avéré à la suite d'essais que les capteurs pouvaient ne plus avoir dans leur champ en fin d'opération qu'une partie de la zone chauffée, l'autre partie étant occultée par le collier chauffant.The device of Figure 6 aims to remedy a difficulty resulting from the fact that, in the implementation of the method, it is necessary to move the heating collar back during the course of the operation, the heated area tending to move forward due to the progression of the metal element, the heating of which is not instantaneous. When the temperature of the heated zone is detected by means of temperature sensors arranged so as to form an angle relative to the axis sufficiently acute to target the heated zone under the heating collar, it has been found to be following tests that the sensors could have in their field at the end of the operation only part of the heated area, the other part being obscured by the heating collar.

Le procédé correspondant au dispositif représenté dans cette figure a pour but de remédier à cet inconvénient et de permettre une observation constante de la température maximale de la zone chauffée sur tout son pourtour, et par suite une correction appropriée des apports thermiques sur le pourtour de l'élément à cintrer, et une réduction maximale des défauts dans la forme de l'élément métallique cintré.The method corresponding to the device shown in this figure aims to remedy this drawback and to allow constant observation of the maximum temperature of the heated area around its entire periphery, and consequently an appropriate correction of the thermal inputs around the periphery of the element to be bent, and maximum reduction of defects in the shape of the bent metal element.

Dans le dispositif de la figure 6, le tube 71 est poussé dans le sens de la flèche. Le collier chauffant 72 est disposé dans la période initiale du préchauffage en position 72A, puis il est reculé pendant l'opération de cintrage dans la position 72B. Le tore de refroidissement par pulvérisation d'eau, initialement en position 73A, est reculé avec le collier chauffant dans la position 73B.In the device of Figure 6, the tube 71 is pushed in the direction of the arrow. The heating collar 72 is placed in the initial preheating period in position 72A, then it is moved back during the bending operation in position 72B. The water spray cooling toroid, initially in position 73A, is moved back with the heating collar to position 73B.

Les détecteurs de température à infra-rouge sont portés par des bras 74, fixés à un support mobile 75. In seul bras 74 a été représenté sur la figure pour plus de clarté, mais on comprendra qu'il y en a en réalité plusieurs répartis sur le pourtour du tube, par exemple quatre à 90° l'un de l'autre. Le bras 74 porte deux pinces de préhension des détecteurs, la pince 76 portant le détecteur 77, d'axe de visée faisant un angle aigu avec l'axe d'avancement du tube, et le détecteur 79, d'axe de visée perpendiculaire à ce même axe d'avancement. Le support mobile et le bras sont animés d'un mouvement de va-et-vient d'amplitude A L.The infrared temperature detectors are carried by arms 74, fixed to a movable support 75. In only one arm 74 has been shown in the figure for clarity, but it will be understood that there are in reality several distributed around the tube, for example four at 90 ° one the other. The arm 74 carries two gripping grippers for the detectors, the gripper 76 carrying the detector 77, with an aiming axis making an acute angle with the axis of advancement of the tube, and the detector 79, with an aiming axis perpendicular to this same line of advancement. The mobile support and the arm are moved back and forth with amplitude A L.

Pendant une période de ce va-et-vient, le bras 76 et le détecteur 77 avancent donc jusqu'aux positions 76A et 77A, puis reviennent à leurs positions initiales. De même, le bras 78 et le détecteur 79 avancent jusqu'aux positions 78A et 79A, puis reviennent à leurs positions initiales. Pendant la phase initiale de préchauffage, le champ de balayage par les détecteurs est représenté en grisé sur la figure (80). Le détecteur 77 balaie sensiblement toute la zone chauffée. Lorsque le collier chauffant a été reculé jusqu'à la position 72B, la zone chauffée est en partie occultée au détecteur 77, mais la reste de cette zone est dans le champ balayé par le détecteur 79. On peut ainsi, à l'aide d'une chaîne de multiplexage à détection de crêtes de température respectives pour les détecteurs 77 et 79, puis comparaison des valeurs maximales avec sélection de la plus élevée, obtenir à tout instant la température maximale sur les différentes génératrices du pourtour de la zone chauffée, et effectuer la correction appropriée de l'apport thermique sur chacune des secteurs correspondants de celui-ci.During a period of this back-and-forth, the arm 76 and the detector 77 therefore advance to positions 76A and 77A, then return to their initial positions. Likewise, the arm 78 and the detector 79 advance to positions 78A and 79A, then return to their initial positions. During the initial preheating phase, the scanning field by the detectors is shown in gray in the figure (80). The detector 77 scans substantially the entire heated area. When the heating collar has been moved back to position 72B, the heated area is partly obscured by the detector 77, but the rest of this area is in the field scanned by the detector 79. It is thus possible, using '' a multiplexing chain with detection of respective temperature peaks for detectors 77 and 79, then comparison of the maximum values with selection of the highest, obtaining at all times the maximum temperature on the various generators around the heated zone, and perform the appropriate correction of the heat input on each of the corresponding sectors thereof.

Dans le cadre de l'invention, la dissymétrie d'apport thermique à la zone chauffée pourrait être détectée par la mesure d'autres propriétés physiques que le rayonnement infra-rouge.In the context of the invention, the asymmetry of thermal contribution to the heated zone could be detected by measuring other physical properties than infrared radiation.

Claims (15)

1. A method for bending a long metal member of constant cross-section by Ically heating a narrow zone on the periphery of said member by means of a heating collar (6) which surrounds said zone, by exerting thrust on one end of the member and holding its other end by means of a pivoting arm (3), wherein the temperature of the heated zone on the periphery of the member is kept substantially constant by detecting the temperature of the latter, and the thermal supply is increased or decreased at one or the other of the points of said periphery of the member according to whether the detected temperature there is lower or higher than a nominal value which corresponds to a uniform temperature of the periphery of the heated zone, characterized in that the temperature of the heated zone is detected in at least two points of the periphery of the member, one being located on the side of the center of bending and the other opposed to the first, by means of sensors (12, fig. 2), which are made to move to-and-fro (12A) parallelly to the axis of the member which has not yet been bent, and scan the width of the heated zone.
2. A method according to claim 1, characterized in that the temperature of the heated zone is measured at four points located 90° to one another.
3. A method according to claim 1 or 2, characterised in that the temperature of the heated zone is detected by inspection of the latter, on the one hand by means of a first set of sensors (77) disposed upstream of the heated zone and the axis of which forms an acute angle with the axis of the still unbent member, and on the other hand by means of a second set of sensors (79) disposed at a longitudinal distance from the first ones and of such an orientation, that it is possible to observe the portion of the heated zone which can be screened with respect to the first set of sensors by the heating collar during a part of the bending operation.
4. A method according to claim 3, characterized in that the heated zone is observed by means of the second set of sensors (79) perpendicularly to the axis of the still unbent member, and in that it is kept at a fixed distance from the first set to allow it to observe the portion of the heated zone which is downstream from the heating collar, at least during the interval of time in which this portion is screened relatively to the first set of sensors.
5. A method according to claim 3, characterized in that the temperatures observed by the first and second set of sensors are continuously compared and only the highest values observed are taken into consideration to increase or reduce the input of heat to the corresponding sectors of the heated zone.
6. A method according to claim 1, characterized in that the input of heat is increased or reduced in the detection zones by supplying constant power to a heating collar (6, fig. 6) which power corresponds to the minimum deformation temperature of the heated zone of the long member, and by bringing additional heating elements (61, 62, 63, 64) disposed facing the detection zones closer thereto or further apart therefrom or by modifying the power supply to these additional heating elements.
7. An apparatus for bending a long metal member whose cross-section is constant, including a heating collar (6) which surrounds the zone to be heated to allow bending, means for pushing said member, a pivoting arm (3) to support the other end of the member, detectors (12) for detecting the temperature of the heated zone and means for increasing or reducing the heat supply in one or another point of the metal member according to the fact if the temperature there is lower or higher than a nominal value corresponding to a uniform temperature of the periphery of the heated zone, characterized in that the detectors for detecting the temperature of the heated zone are disposed in at least two points of the periphery of the member, one on the side of the bending member and the other on the opposite side, and in that it comprises means for moving (12A) the detectors longitudinally to and fro, thus permitting them to scan the width of the heated zone.
8. An apparatus according to claim 7, characterized in that it includes four infrared radiation temperature detectors disposed at 90° from one another.
9. An apparatus according to claim 7, characterized in that the temperature detectors are connected via a multiplexing device (24, fig. 3) on the one hand to distinct temperature recorders (34, 35, 36, 37) and on the other hand to a peak detect and hold circuit (27) and to a device for displaying the peak temperature (30).
10. An apparatus according to claim 9, characterized in that it further includes a device for displaying temperatures successively in the same recorder (34).
11. An apparatus according to claims 9 or 10, characterized in that its multiplexing device (24) is connected to a peak detector (27) for each sensor, as well as to a selector for the highest peak observed by each couple of corresponding sensors of the two sets, and to a device for displaying the maximum temperatures.
12. An apparatus according to claim 7, characterized in that the temperature detectors are connected to servomotors, on the one hand for an overall movement of the heating collar (51, 52, fig. 5) and on the other hand for deforming the latter (53).
13. An apparatus according to claim 7, characterized in that the heating collar consists of an inner collar (6, fig. 6) which supplies a constant power corresponding to the minimum deformation temperature of the heated zone, and of additional heating elements 61, 62, 63, 64) disposed facing the detection zones, and in that it further includes means for bringing the additional heating elements closer to or further from the long metal member or to modify the power which is supplied thereto.
14. An apparatus according to claim 13, characterized in that the additional heating elements are inductors.
15. An apparatus according to claim 7, characterized in that the heating collar is an induction collar.
EP81105933A 1980-08-05 1981-07-28 Method and apparatus for bending a long metal object Expired EP0045470B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR8017297 1980-08-05
FR8017297A FR2488162B1 (en) 1980-08-05 1980-08-05 METHOD AND DEVICE FOR BENDING AN ELONGATED METAL MEMBER
FR8100539A FR2497697A2 (en) 1981-01-14 1981-01-14 Elongated metallic element bending process - detects heated zone temp. or clearance between element and heater for adjustment from comparison with reference value
FR8100539 1981-01-14

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EP0045470A1 EP0045470A1 (en) 1982-02-10
EP0045470B1 true EP0045470B1 (en) 1986-01-29

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DE (1) DE3173625D1 (en)

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FR2598945B1 (en) * 1986-05-26 1988-07-22 Stein Industrie DEVICE FOR BENDING AN ELONGATED METAL MEMBER
GB0613165D0 (en) * 2006-06-28 2006-08-09 Univ Warwick Real-time infrared measurement and imaging system
EP2390018B1 (en) * 2009-01-21 2016-11-16 Nippon Steel & Sumitomo Metal Corporation Curved metallic material and process for producing same
BR112012000950B1 (en) * 2009-07-14 2020-01-07 Sumitomo Pipe & Tube Co., Ltd. METHOD AND APPARATUS FOR MAKING A CURVED MEMBER
EP2327486B1 (en) * 2009-11-26 2012-05-23 DALMINE S.p.A. Method for making lined pipe bends
DE102010013090A1 (en) * 2010-03-26 2011-11-17 Benteler Automobiltechnik Gmbh Method and device for bending hollow sections
EP3150296A4 (en) * 2014-05-27 2018-02-07 Nippon Steel & Sumitomo Metal Corporation Manufacturing method for bent member and hot-bending processing apparatus for steel material
FR3048628B1 (en) 2016-03-11 2018-07-13 Stelia Aerospace MACHINE AND METHOD FOR BENDING A LONGITUDINAL CYLINDRICAL PIPE
CN106140907B (en) * 2016-08-05 2018-12-11 北京隆盛泰科石油管科技有限公司 A kind of Hi-grade steel induction heating syphon dual temperature stewing method processed
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EP0045470A1 (en) 1982-02-10
US4414833A (en) 1983-11-15

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