• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Induction welding device of tubes with variable diameter comprising three inductors (2), with a configuration in the form of a cam, located in symmetry with respect to the axial axis of the tube (1) to be welded, an oscillator (3) connected to each inductor (2), a mechanical system connected to each inductor (2), intended to force the contact of each inductor (2) with the tube (1) by the corresponding measurement depending on the diameter of the tube (1) in each position, so that the position of the inductors (2) with respect to the tube (1) varies radially as the diameter of the section to be welded of the tube (1) varies. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2646991A1
    申请号:ES201630825
    申请日:2016-06-17
    公开日:2017-12-18
    发明作者:Pedro MORATALLA MARTINEZ；Juan Carlos Rodriguez Lara；Cesar CASES SANCHIS；Manuel DURAN SANCHEZ；Jose Miguel MAGRANER CACERES
    申请人:GH Electrotermia SA；
    IPC主号:
    专利说明:

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    PIPE INDUCTION WELDING PROCESS WITH VARIABLE DIAMETER
    AND DEVICE TO CARRY IT OUT
    DESCRIPTION
    OBJECT OF THE INVENTION
    The present invention relates to a process for carrying out induction welding of tubes with variable diameter. The invention also relates to the device for carrying out said process. The tube to be welded can have a section not only circular but of any other geometry. In addition, the tube can be manufactured in a wide variety of materials such as, for example, brass, copper, steel or stainless steel among others, with the sole requirement of being an electrically conductive material.
    Find special application in the field of induction tube welding industry.
    TECHNICAL PROBLEM TO BE RESOLVED AND BACKGROUND OF THE INVENTION
    In the current state of the art, induction tube welding is performed by applying a coil, which acts as an inductor, wound by the outer surface of the tube and coupled as close as possible to the surface of the element to weld Normally, the coil is wound on a structure that has the configuration of the outer surface of the tube. An electric current is circulated through the coil that generates induced currents in the tube that, essentially, materialize in two types of currents. One of them is a current that circulates inside the tube body radially. The other current circulates circumferentially through the tube body and through the mechanical seal that is intended to be welded, known as the welding V. To generate the weld along the tube, the structure with the coil moves along the tube as the weld is created.
    Of these two currents generated in the tube, only the one that circulates through the welding V is useful for welding the tube, the radial current being considered, directly, as a loss of energy. In this way, the higher this current, the lower the efficiency of the system.
    Thus, it is known in the sector, which is a priority when it comes to welding induction tubes, that this induced current is reduced to a minimum. This leads to
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    This procedure proceeds to increase the impedance of the tube which, normally, is done by incorporating a field concentrator block, commonly known as "impeder", inside the tube.
    Document ES-0479528_A1 discloses an invention which has as its object an induction welding installation for the manufacture of tubes. The invention applies mainly to stainless steel tubes, but tubes of other metals can also be advantageously welded in the installation according to the invention. The induction welding installation for the manufacture of tubes comprises an induction coil that surrounds an elementary piece of tube whose edges determine a groove that narrows downstream, forging rollers located downstream of the induction coil, which they apply against each other the heated edges of the piece or elementary tube in the place of a welding point located in the vicinity of a plane that joins the axes of the forging rollers, and an internal concentrator, arranged inside the piece or elementary tube, with a stack of magnetizable plates oriented parallel to the diameter of the tube that passes through the groove of the elementary piece and longer than the distance between the upstream end of the induction coil and the axes of the rollers of forging.
    However, the induction welding technique is applicable when the coupling between the inductor and the tube is optimal, that is, when the distance between the two elements is very small, the current induced in the tube being maximum. As the distance between the inductor and the tube increases, the efficiency decreases exponentially, reaching a point where the current induced in the tube is reduced to a level where no welding occurs.
    Due to this effect, the use of this method for welding variable diameter tubes presents a series of problems whose magnitude makes it not a practice used. The reason is that, in the areas of the tube with a larger diameter, the welding is optimal but, as the inductor moves along the tube towards areas of smaller diameter, the coupling is reduced, increasing the distance between the inductor and the tube and decreasing the value of the induced current or, what is the same, the efficiency of the welding, until reaching a point where the value of the induced current has been reduced so much, that welding does not occur .
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    The present invention solves this problem, which is not solved in the present state of the art, by using a multiple inductor system capable of creating an induced current in the constant value tube even though the tube has a variable section
    DESCRIPTION OF THE INVENTION
    The present invention describes a tube induction welding device with variable diameter. The device comprises at least two inductors, although preferably there are three, an oscillator connected to each inductor and a mechanical system connected to each inductor.
    It is important that the inductors are located in symmetry with respect to the axial axis of the tube to be welded, that is, radially.
    To ensure the contact of the inductors with the tube, one of the features available to the device is the geometric configuration of the inductors. In this way, a cross-section of an inductor comprises a zone with a smaller diameter, a zone with a larger diameter and an intermediate zone, like a cam.
    Another feature of the device to ensure the inductors contact with the tube is the incorporation of a mechanical system connected to each of the inductors formed, for example, by springs or tensioners, by means of which a voltage in the inductors is achieved that force the contact with the tube through the corresponding area depending on the diameter of the tube in each position.
    A requirement that inductors are requested is that they be connected to the same electric generator, so that the currents they generate are in phase.
    The invention also describes the process for carrying out welding. In this way, the welding process carried out by means of the device of the invention comprises the phases described below, considering that, initially, each of the inductors is connected to an oscillator and a mechanical system and that all Inductors are connected to the same electricity generator:
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    a) Position each of the inductors radially distributed in symmetry around a section of a tube to be welded.
    b) Activate the mechanical system, forcing the inductors to keep in continuous contact with the tube.
    c) Connect the electric generator to supply current to the inductors.
    d) Move the tube to form the weld.
    In addition to this process, the fact of positioning an impeder inside the tube before phase c) can be considered, and also that the impeder is positioned in proximity to the area of the tube to be welded.
    BRIEF DESCRIPTION OF THE FIGURES
    To complete the invention that is being described and in order to help a better understanding of the features of the invention, according to a preferred embodiment of the invention, a set of drawings is attached where, for illustrative purposes and not limiting, the following figures have been represented:
    - Figure 1 represents a perspective view of a tube in the process of induction welding according to the traditional method.
    - Figure 2 represents a front view of a tube in the process of induction welding according to the present invention in the area of the tube with larger diameter.
    - Figure 3 represents a front view of a tube in the process of induction welding according to the present invention in an area of the tube with an intermediate diameter.
    - Figure 4 represents a front view of a tube in induction welding process according to the present invention in the area of the tube with smaller diameter.
    - Figure 5 represents a view of Figure 3 including only one inductor.
    The following is a list of the references used in the figures:
    1. Tube
    2. Inductor.
    3. Oscillator.
    4. Impeder.
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    DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
    As mentioned, the main problem of induction welding of tubes (1) arises when the section of the tubes (1) to be welded is variable, causing the reduction in diameter a decrease in the coupling between the inductor and the tube ( 1) that causes the induced current to reduce exponentially until a time comes when it is not capable of producing welding.
    To avoid this effect, the present invention describes a device comprising a plurality of inductors (2) connected to a single generator, so that the phases of the inductors (2) are synchronized.
    An example of configuration of a tube (1) to be welded by induction according to prior art procedures is shown in Figure 1. Plates arrive to the system, for the configuration of the tubes (1), which are shaped by a series of forming drums that are responsible for giving the tube (1) the definitive circular configuration. The impeller (4) is located between the forming drums, so that the tube (1) remains inside as it is configured. In this system, all the elements remain static in one position, the tube being the one that moves as the welding is carried out. Thus, the impeder (4) can be positioned according to the needs by having a free zone by which it can be held by the end zone of the tube (1).
    In the present invention the configuration system can be similar, taking into account that, on the one hand, the diameter of the tube (1) to be welded is not constant, so that the forming drums must have a way of varying the position to provide a variable section and that, on the other hand, the system of the invention is applicable to tubes of any section, being able to be polygonal sections. In any case, the configuration system of the tube (1) is not part of the object of the invention, so it is not necessary to go into greater detail.
    In a preferred embodiment, a system with three inductors (2) has been represented, considered as the configuration that makes the system more efficient in terms of number of inductors (2). The system can also incorporate only two inductors (2), although the efficiency of the system is reduced. On the contrary, a number of inductors (2)
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    greater than three creates problems in terms of interference between components and efficiency does not increase significantly.
    As shown in Figures 2 to 4 and, more clearly in Figure 5, where only one of the inductors (2) has been represented in order to provide more clarity to the mode of operation of the invention, the inductors (2 ) are configured with a cam-shaped geometry that incorporates two zones with two different diameters joined by a transition curve. These two diameters correspond to the minimum and maximum diameters of the tube (1) to be welded, which are preferably increased with a safety margin that is usually between 5 and 15 mm.
    Each of the inductors (2) is associated with a heating station, which has the function of adapting the load so that the inductor (2) is able to deliver all the power to the tube (1). The heating station may have different configurations depending on the frequency and power required to deliver. It can incorporate an output transformer, it can be a series, parallel oscillating circuit, etc.
    In a preferred embodiment, the heating station is an oscillator (3) capable of operating in a wide range of frequencies. In any case, typical values for acceptable weld quality range between 100 and 400 kHz.
    Each of the inductor (2) and oscillator (3) assemblies has a mechanical system associated with the ability to move and position the inductor (2) with respect to the tube (1) depending on the diameter of the tube (1) in each determined position , so that the coupling between the tube (1) and the inductor (2) is optimal at all times. This mechanical system has not been shown in the figures and can be any of those known in the state of the art, such as a spring system that pulls the inductors radially (2) with the intention of forcing the contact of the surface of the inductor (2) depending on the diameter of the tube (1) in each of the determined positions.
    In Figures 2, 3 and 4 you can see the inductors (2) adapted, respectively, to the area of greater diameter of a tube (1), to an area of intermediate diameter and to the area of smaller diameter, being reflected as the inductors (2) are adapted to the measurement of the section of the tube (1) as the welding progresses through the tube (1) and, therefore,
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    the tube (1) is modifying the section that is going to be welded in each moment. In these figures the impeder (4) has not been represented as it is considered an element that does not provide information to the system configuration. However, the impeder (4) has been represented in Figure 5, where only one of the inductors (2) appears, considering that the simplification in the figure does allow it to be introduced without removing clarity.
    In a preferred embodiment, all inductors (2) are connected to the same generator, so that they are in phase. In case of being connected to independent generators, the currents generated by the inductors (2) would not be in phase, so that the drop in performance would be considerable.
    With respect to the impeder (4), it should be positioned as close as possible to the weld, so that the radial leakage currents through the tube (1) are minimized. In the case of linear welding of a tube (1), the position of the impeder (4) should not vary, but there are situations in which the welding is not linear, as is the case, for example, of tube configuration (1) by helical welding.
    The invention has the following advantages over other systems known in the state of the art:
    1. Welding occurs without physical contact between the tube (1) and the inductor (2). There are welding systems with physical contact, which have the disadvantage of suffering very fast wear and, in addition, of needing a high complexity during their adjustment. Being the transmission by contact, the mechanics must be very precise to guarantee contact at all times. With the non-contact system, the position of the tube (1) with respect to the inductor (2) can vary slightly without the generation of induced current and without, therefore, compromising the quality of the weld.
    2. The durability of the inductors (2) is very high compared to the contact welding process that also requires a cleaning and wear control of the inductors.
    3. Variable diameter tubes can be welded by induction, which is not possible with the traditional induction tube welding process.
    Finally, it should be considered that the present invention should not be limited to the embodiment described herein. Other configurations can be made by those skilled in the art in view of the present description. Accordingly, the scope of the invention is defined by the following claims.
    权利要求:
    Claims (7)
    [1]
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    1. - Induction welding device for tubes with variable diameter, characterized in that it comprises:
    - at least two inductors (2), located in symmetry with respect to the axial axis of the tube (1) to be welded,
    - an oscillator (3) connected to each inductor (2), and
    - a mechanical system connected to each inductor (2), where,
    - the inductors (2) have a configuration comprising a zone with a smaller diameter, a zone with a larger diameter and an intermediate zone,
    - the mechanical systems force the contact of each inductor (2) with the tube (1) by the corresponding measurement depending on the diameter of the tube (1) in each position,
    so that the position of the inductors (2) with respect to the tube (1) varies radially as the diameter of the section to be welded of the tube (1) varies.
    [2]
    2. - Induction welding device for tubes with variable diameter, according to claim 1, characterized in that it comprises three inductors.
    [3]
    3. - Induction welding device for tubes with variable diameter, according to claims 1 or 2, characterized in that the inductors (2) are connected to the same generator, so that the currents they generate are in phase.
    [4]
    4. - Induction welding device for tubes with variable diameter, according to any of claims 1 to 3, characterized in that the mechanical system comprises a spring that forces the contact of the inductor (2) corresponding to the tube (1).
    [5]
    5. - Process of induction welding of tubes with variable diameter, carried out by means of the device defined in any of the preceding claims, characterized in that, having each of the inductors (2) connected to an oscillator (3) and a Mechanical system and all inductors (2) connected to the same electricity generator, includes the following phases:
    e) Position each of the inductors (2) radially distributed in symmetry around a section of a tube (1) to be welded.
    f) Activate the mechanical system, forcing the inductors (2) to keep in continuous contact with the tube (1).
    g) Connect the electric generator to supply current to the inductors (2).
    h) Move the tube to form the weld.
    [6]
    6. Induction welding process of tubes with variable diameter, according to claim 5, characterized in that before the phase c) an impeder (4) is positioned inside the tube (1).
    [7]
    7. Induction welding process of tubes with variable diameter, according to claim 6, characterized in that the impeder (4) is positioned in proximity to the area of the tube (1) to be welded.
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    同族专利:
    公开号 | 公开日
    DE102017210017A1|2017-12-21|
    US20170361393A1|2017-12-21|
    ES2646991B1|2018-09-27|
    US10391583B2|2019-08-27|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE3913897A1|1989-04-27|1990-10-31|Kurt Dr Gruber|Prodn. of thick-walled welded steel tubes - using two coils to heat edges up to welding temp. with first coil lying in welding direction|
    JP2000003778A|1998-06-16|2000-01-07|Mitsubishi Heavy Ind Ltd|Induction coil and heating device|
    US20140339219A1|2013-05-14|2014-11-20|Thermatool Corp.|Induction Coil with Dynamically Variable Coil Geometry|
    US3414697A|1965-02-25|1968-12-03|American Mach & Foundry|Tube welding by induction heating|
    US3689725A|1970-08-14|1972-09-05|Republic Steel Corp|Apparatus for high speed welding of stainless steel tube with high velocity gas|
    US4268736A|1978-04-13|1981-05-19|American Electric Fusion Co., Inc.|Induction welding apparatus for manufacture of tubing|
    JP3788156B2|2000-01-12|2006-06-21|日立電線株式会社|Method for producing compound semiconductor single crystal and PBN container used therefor|
    US20080308550A1|2007-06-13|2008-12-18|Fluxtrol Inc.|Magnetic flux guide for continuous high frequency welding of closed profiles|
    法律状态:
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    优先权:
    申请号 | 申请日 | 专利标题
    ES201630825A|ES2646991B1|2016-06-17|2016-06-17|PIPE INDUCTION WELDING PROCESS WITH VARIABLE DIAMETER AND DEVICE FOR CARRYING OUT|ES201630825A| ES2646991B1|2016-06-17|2016-06-17|PIPE INDUCTION WELDING PROCESS WITH VARIABLE DIAMETER AND DEVICE FOR CARRYING OUT|
    DE102017210017.6A| DE102017210017A1|2016-06-17|2017-06-14|Induction welding method for variable diameter pipes including appropriate device|
    US15/625,259| US10391583B2|2016-06-17|2017-06-16|Induction welding process for variable diameter pipes and device for carrying out said process|
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