The present application is a National Phase Entry of PCT International Application No. PCT/US2015/010919, which was filed on Jan. 9, 2015, the contents of which are hereby incorporated by reference.
The present disclosure relates generally to systems and methods for thermally treating continuous materials and, more specifically, to systems and methods for rapid, inline thermal treatment of continuous products.
A continuous product, as used herein, refers to a product, such as a sheet, strip, or wire, that is manufactured using a continuous production system. For example, during the manufacture of a continuous product, a continuous material may be provided from a cylinder (e.g., a spool or reel) and may proceed through any number of inline manufacturing steps, one directly after another, such that the output of one step serves as the input to the following step, until the continuous product is fully formed and packaged. It is not uncommon for one or more of these manufacturing steps to inadvertently or intentionally impart organics to the surface of the continuous product. These contaminates may include, for example, temporary coatings, lubricants, and other organic compounds. It may be desirable to remove these organic contaminates to avoid contamination between manufacturing steps or before the product is packaged to improve the appearance and usability of the continuous product.
One method of removing these organic contaminants from the surface of a continuous product involves using organic solvents (e.g., fluorocarbons) to dissolve and wash these contaminates from the surface of the product. However, using organic solvents to clean the surface of the product has several disadvantages. For example, these disadvantages include the amount of cleaning time required as well as the additional cost and equipment associated with managing organic solvent fumes and/or recycling the organic solvent.
Another method of removing these organic contaminants from the surface of a continuous product involves batch thermal treatment of the continuous product as an intermediate process after production and prior to packaging. For this method, the continuous product may be loaded onto a temporary holder (e.g., cylinder, bobbin, or reel) then placed within a furnace to heat the product to a sufficient temperature to remove the organic contaminates from the surface. However, this method also has several disadvantages, including the additional time, cost, and equipment associated with: loading the continuous product onto the temporary holder, transporting the product to the furnace, heating the furnace to a suitable temperature to remove the organic contaminates, allowing the product to cool, removing the product from the furnace, and then transferring the continuous product from the temporary holder to another holder (e.g., cylinder, bobbin, or reel) for packaging. Additionally, this method consumes a substantial amount of energy, in the form of electricity and/or fuel, to heat the entire interior of the furnace to a suitable temperature to remove the organic contaminates from the surface of the continuous product. Furthermore, since the continuous product is loaded onto the temporary holder before being loaded in the furnace, the outer portions of the product will not heat up at the same rate as the portions of the product disposed beneath, closer to the temporary holder. As such, this method does not allow for uniform, controlled heating of the continuous product.
The present disclosure relates generally to systems and methods for the inline thermal treatment of continuous products. More specifically, the present disclosure is directed toward systems and methods for the inline thermal treatment of conductive continuous products using resistive heating.
In an embodiment, an inline thermal treatment system for thermally treating a continuous conductive product includes a first electrode configured to contact a continuous conductive product and a second electrode configured to contact the continuous conductive product, such that a portion of the continuous conductive product is disposed between the first and second electrodes. The inline thermal treatment system includes a power source coupled to the first electrode and to the second electrode, wherein the power source is configured to apply an electrical bias between the first electrode and the second electrode to resistively heat the portion of the continuous conductive product disposed between the first and second electrodes.
In another embodiment, a method includes advancing a continuous conductive product through an inline thermal treatment system. The method includes resistively heating the continuous conductive product by applying an electrical bias between a first electrode and a second electrode electrically contacting the continuous conductive product. The method includes supplying at least one gas flow to modify an atmosphere near the continuous conductive product during and/or after resistively heating the continuous conductive product.
In another embodiment, a continuous production system for manufacturing a continuous conductive product includes an inline production system configured to receive a continuous material and to output a continuous conductive product, and includes an inline thermal treatment system configured to receive the continuous conductive product from the inline production system and to output a thermally treated continuous conductive product. The inline thermal treatment system includes a first electrode and a second electrode configured to contact the continuous conductive product, a gas supply system configured to supply a gas flow near the continuous conductive product, and a power source configured to apply an electrical bias between the first and the second electrode to resistively heat a portion of the continuous conductive product disposed between the first and second electrodes. The continuous production system includes a controller comprising a memory and a processor, wherein the controller is configured to control the inline production system and the inline thermal treatment system based on instructions stored in the memory.
These and other features, aspects, and advantages of the present technique will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present disclosure will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
Present embodiments are directed toward systems and methods for inline thermal treatment of continuous products. Continuous products, as discussed herein, include any continuously produced structure, such as a sheet or plate, a strip, a solid wire, or a tubular wire made from a conductive material (e.g., steel, iron or low-alloy ferrous material, high-alloy ferrous material, cobalt-based alloy, nickel-based alloy, or copper-based alloy) or a non-conductive material (e.g., carbon-based products, carbon-fiber products, semiconductor products, or ceramic products). As used herein, a conductive continuous product generally has a resistivity less than or equal to approximately 10 Ohm·meters, and a non-conductive continuous product generally has a resistivity greater than or equal to approximately 1×1014 Ohm·meters. Thermal treatment, as used herein, refers to subjecting the continuous product to at least one thermal cycle, wherein the continuous product is first rapidly heated and then subsequently cooled. It should be understood that continuous products may be generally described as having a direction of motion that coincides with the length (e.g., longest dimension) of the continuous product. As such, it may be noted that the terms upstream and downstream are used herein to describe the relative positions of two elements of a continuous production system or thermal treatment system relative to the motion of the continuous product through the continuous production system. Certain elements of the thermal treatment systems may be described as having longitudinal positions relative to the continuous product, which are positions along the path that the continuous product traverses through the thermal treatment system. Further, certain elements of the thermal treatment system may be described as having radial positions relative to a continuous product (e.g., a continuous wire product having a circular cross-section), which are radial positions about the axis that coincides with the length and/or motion of the continuous product as it traverses the thermal treatment system (e.g., the axis extending through the center and along the length of a continuous wire product).
The disclosed thermal treatment systems may be positioned inline with the production and/or packaging equipment of the continuous production system, which provides substantial advantages over batch thermal treatment in terms of time and operational cost. As set forth above, the surfaces of continuous products may include organic contaminants (e.g., lubricants and/or coatings) from various processing steps, and these organic contaminates may be removed (e.g., degraded and/or vaporized) via the disclosed inline thermal treatment systems. Additionally, the disclosed thermal treatment systems may be used to produce a physical transformation, such as a phase change or a chemical reaction, inside or on the surface of certain types of continuous products. As such, in addition to cleaning the surfaces of the continuous product, certain disclosed thermal treatment systems may be used to thoroughly dry a continuous product of solvent or moisture, to alter the microstructure of a continuous product via sintering, and/or to form a glassy surface layer on a continuous product. Furthermore, in certain embodiments, the disclosed thermal treatment systems may utilize resistive heating, plasma heating, or laser heating to thermally treat a variety of conductive or non-conductive continuous products. It may be appreciated that each of these heating methods enables direct, rapid heating of a portion of the continuous product.
One specific example of a continuous production system 10 presently contemplated is a continuous production system 10 for the manufacture of tubular welding wires. It will be appreciated that, while the present example relates to the production of tubular welding wires, other continuously produced products, such as other wires, strips, sheet, or plates that are made of metals, ceramics, or semiconductors may utilize the inline thermal treatment techniques described herein. For this example, the continuous raw or intermediate material 18 may be a continuous metal strip that may be fed into the processing system 12 from a spool or cylinder. It should be appreciated that, in certain embodiments, when a first spool of the metal strip is depleted, a second spool of the of the metal strip may be loaded, and the end portion of the metal strip from the first spool may be butt welded to the beginning portion of the metal strip of the second spool to provide a substantially continuous supply of the metal strip to the continuous production system 10.
Continuing through the example, the processing system 12 receives the continuous raw or intermediate material 18 (e.g., the metal strip), and performs one or more manipulations of the metal strip to form the continuous product 20 (e.g., a welding wire). These manipulations may involve, for example, tensioning, shaping, bending, rolling, extruding, compressing, and/or texturing the metal strip. Additionally, these manipulations may include adding a granular core material to the partially shaped metal strip, compressing the metal strip around the granular core material, or any other suitable manipulation to form the metal strip into a welding wire. It may be appreciated that lubricants added to the surfaces of the metal strip may facilitate these manipulations.
Next, continuing through the example, the thermal treatment system 14 receives the continuous product 20 (e.g., the tubular welding wire), and applies one or more heating and cooling cycles to thermally treat the welding wire. In certain embodiments, the primary purpose of the thermal treatment may be to remove any organic lubricants or coatings from the surface of the welding wire. However, in certain embodiments, the thermal treatment may also be effective at removing residual moisture or organic solvents from the welding wire (e.g., from the metal strip or from the granular core of the welding wire), which may improve the performance and shelf-life of certain welding wires. Additionally, in certain embodiments, the thermal treatment may be used to sinter the granular core of a welding wire. As such, it may be appreciated that, in addition to removing undesired organics from the surface of welding wires, the thermal treatment provided by the thermal treatment system 14 may, in certain embodiments, be useful to intentionally alter the physical and/or chemical nature of the welding wire as a part of the continuous production system 10.
Next, continuing through the example, the packaging system 16 receives the thermally treated continuous product 26 (e.g., the thermally treated welding wire) from the thermal treatment system 14. For example, the packaging system 16 may, in certain embodiments, cut the welding wire to particular lengths that are loaded onto spools for distribution and/or retail. In certain embodiments, the packaging system 16 may alternatively package the welding wire into coils, boxes, drums, or other suitable packages or dispensing mechanisms.
Accordingly, the presently disclosed inline thermal treatment system 14 may be useful to the manufacture of a continuous product. As set forth below, the disclosed thermal treatment system 14 may be implemented using one of three different heating methods, each with utility for certain types of continuous products. The heating methods disclosed include: resistive heating (for conductive continuous products), plasma heating (for conductive and non-conductive continuous products), and laser heating (for conductive and non-conductive continuous products). Each of these embodiments is discussed in detail below.
Resistive Heating
In certain embodiments of the present approach, the inline thermal treatment system 14 may use resistive heating to thermally treat electrically conductive continuous products. Resistive heating (also known as Joule heating or ohmic heating) refers to the heat released as a result of current flowing through a conductive material. For embodiments of the thermal treatment system 14 that use resistive heating, electrodes are generally placed along the surface of the continuous product so that, when a suitable electrical bias (e.g., voltage) is applied to the electrodes, current traverses and resistively heats the portion of the continuous product disposed between the electrodes.
The thermal treatment system 42 also includes a first electrode 50 and a second electrode 52 disposed within the housing 44. In particular, the first and second electrodes 50 and 52 illustrated in
The electrodes 50 and 52 are generally made of a highly conductive material. For example, in certain embodiments, the electrodes 50 and 52 include silver, copper, aluminum, tungsten, or alloys thereof. More specifically, in certain embodiments, the electrodes 50 and 52 may be made from sintered compounds based on copper or silver, or from precipitation-enhanced alloys such as copper-beryllium. Additionally, in certain embodiments, the electrodes 50 and 52 may include an abrasion resistant material such as tungsten carbide to improve the longevity of the electrodes. Furthermore, the electrodes 50 and 52 generally are mounted on insulating blocks or insulating bearings 54 such that the electrodes 50 and 52 are electrically isolated from other portions of the thermal treatment system 42 to prevent interference with the operation of other portions of the continuous production system 40. It may also be noted that the radius 53 of the illustrated electrodes 50 and 52 may be tuned to adjust the amount of contact between the electrodes 50 and 52 and the continuous product 20, the resistance of the electrodes 50 and 52, or to achieve a desired rate of rotation for the electrodes 50 and 52. Furthermore, in certain embodiments, the distance 55 between the electrodes 50 and 52 may be fixed, may be manually varied (e.g., by an operator between manufacturing runs) or may be mechanically varied in an automated manner (e.g., by actuators under the direction of a controller, as discussed below).
As illustrated in
The thermal treatment system 42 illustrated in
Additionally, as illustrated in
The continuous production system 40 includes a controller 64 that is capable of controlling operation of the thermal treatment system 42 as well as the processing system 12 and/or the packaging system 16. For example, the controller 64 may be a programmable logic controller (PLC) or another suitable controller having a memory 66 capable of storing instructions and a processor 68 capable of executing the instructions in order to control the operation of the continuous production system 40 (e.g., the processing system 12, the thermal treatment system 42, and/or the packaging system 16). As such, the illustrated controller 64 is communicatively coupled to the processing system 12, the packaging system 16, as well as components of the thermal treatment system 42, as illustrated by the dotted lines in
As illustrated in
Additionally, as illustrated in
As such, the measurements collected by the sensors 70 (e.g., temperature sensors) may be used by the controller 64 to determine the heating rate and the peak temperature of the portion 58 of the continuous product 20 positioned between the electrodes 50 and 52, as well as the temperature distribution across the continuous product 20. In certain embodiments, the controller 64 may adjust one or more parameters of the continuous production system 40 in order to provide uniform heating of the continuous product. For example, in certain embodiments, uniform heating may involve the controller 64 adjusting parameters of the system 40 to ensure that the average or peak temperatures experienced by different portions of the continuous product 20 vary by less than a particular amount (e.g., less than approximately 10% or less than approximately 5%) as the continuous product 20 traverses the heating zone 22. By specific example, in certain embodiments, the controller 64 may adjust the rate of advancement of the continuous product 20 through the thermal treatment system 44 to achieve the uniform heating in the portion 58 of the continuous product 20. However, since the thermal treatment system 42 is disposed inline with the processing system 12 and the packaging system 16, the rate of advancement of the continuous product 20 throughout the continuous production system 40 would be affected by such a change.
As such, in certain embodiments, the controller 64 may specifically adjust the parameters of the thermal treatment system 42 to achieve uniform heating of the continuous product 20 so that other parameters of the continuous production system 40 (e.g., the rate of advancement of the continuous product 20) may remain unchanged. For example, for the resistive heating thermal treatment system 42 illustrated in
Plasma Heating
In certain embodiments of the present approach, the thermal treatment system 14 of
The heating zone 22 of the plasma thermal treatment system 82 includes one or more plasma torches 84 and one or more corresponding targets 86 disposed within the housing 44. In other embodiments, the plasma thermal treatment system 82 may be implemented without the housing 44. The plasma torches 84 of the thermal treatment system 82 receive electrical power from one or more power sources 56 and a gas flow supplied by the gas supply system 60. For example, in certain embodiments, the plasma torches 84 may be modified versions of welding torches used in gas-tungsten arc welding (GTAW) or plasma welding. The plasma torches 84 each include an electrode (e.g., a non-consumable tungsten electrode) that is capable of ionizing a gas flow when a suitable electrical bias is applied between the electrode of a plasma torch 84 and the corresponding target 86. The targets 86 may be water-cooled copper blocks or other suitable electrically conductive targets capable of rapidly diffusing heat. In certain embodiments, the plasma torches 84 may be water-cooled as well. As such, the plasma torches 84 are each capable of forming a plasma arc 88 that rapidly heats the portion 90 of the continuous product 20 disposed near the plasma arcs 88.
The plasma torches 84 of
It may also be appreciated that, unlike the resistive heating technique discussed above, the plasma arcs 88 may be capable of directly, chemically reacting with organic contaminates that may remain on the surface of the continuous product 20. Indeed, for continuous products in which an oxide layer (e.g., a glassy oxide coating) is desirable, such a layer may be formed when the atmosphere within the housing 44 (or within the gas flow received by the torches 84) is sufficiently reactive (e.g., contains sufficient oxygen). For other continuous products 20, however, an inert atmosphere may be maintained near the continuous product 20 (e.g., within at least a portion of the housing 44) to limit or prevent oxidation of the continuous product 20 during thermal treatment.
In certain embodiments, the gas flow provided to the plasma torches 84 (referred to herein as the plasma gas flow) may consist of argon, helium, or nitrogen, or combinations thereof, which are ionized to form the plasma arcs 88. Additionally, in certain embodiments, the gas flow provided to the one or more gas nozzles 62 of the plasma thermal treatment system 80 may have the same composition as the plasma gas flow while serving a different role as an inert gas or inert gas mixture. In other embodiments, the gas flows may have different compositions. For example, in certain embodiments, the gas flow provided to the one or more gas nozzles 62 may include a reactive gas (e.g., oxygen) directed toward one or more surfaces of the continuous product during and/or after plasma heating to facilitate particular reactions at the surface of the continuous product 20.
For the thermal treatment system 82, a number of parameters may be tuned by the controller 64 to achieve the desired heating (e.g., uniform heating rate, uniform peak temperature, and/or uniform temperature distribution) when thermally treating the continuous product 20. For example, the controller 64 may monitor and control the flow rate of the gas flow supplied to the plasma torches 84 by the gas supply system 60 and the electrical bias applied by the power sources 56 between the electrodes of the plasma torches 84 and the targets 84, which affects the power and the shape of each plasma arc 88. Additionally, the sensors 70 may include direct or indirect temperature sensing devices that are capable of measuring temperatures of the continuous product 20, the plasma arcs 88, or both. For example, the sensors 70 pyrometers that measure the temperature of portions of the continuous product 20 and/or the temperature of the plasma arcs 88. In certain embodiments, the sensors 70 may include cameras that measure the shape and the position of each plasma arc 88 relative to the continuous product 20.
In certain embodiments, the desired heating may be achieved by controlling the positions of the plasma torches 84 and the corresponding targets 86. For example, in certain embodiments, the positions of the plasma torches 84 and the targets 86 may be fixed, manually adjustable, or mechanically adjustable in an automated manner using actuators controlled by the controller 64. For example, the distance between a plasma torch 84 and the corresponding target 86 may be adjusted to control the temperature and the stability of the plasma arc 88. Additionally, the distance between the plasma torch 84 and the continuous product 20 as well as the radial and/or longitudinal position of the torch 84 may be adjusted to achieve the desired heating of the continuous product 20. It may be also noted that, in certain embodiments, the controller 64 may not signal the power sources 56 to apply the electrical bias between the torches 84 and the corresponding targets 86 until the rate of advancement of the continuous product 20 is above a threshold value, until the oxygen and/or moisture content of the atmosphere within the housing 44 is below a threshold value, or a combination thereof. In other embodiments, the controller 64 may signal the power sources 56 to gradually increase applied electrical bias to gradually increase the heat output of the torches 84 proportionally with the gradual increase in the rate of advancement of the continuous product 20.
With the foregoing in mind,
In other embodiments, the plasma arcs 88 may have a transverse orientation with respect to the length and the motion of the continuous product 20.
In particular,
As such, for the example illustrated in
Laser Heating
In certain embodiments of the present approach, the thermal treatment system 14 of
The heating zone 22 of the laser thermal treatment system 102 includes one or more lasers 104 disposed within the housing 44. Compared to the thermal treatment systems discussed above, the laser thermal treatment system 102 may benefit more from the housing 44 to protect the optical components of the system as well as to limit laser light leakage to the surrounding environment. The lasers 104 of the laser thermal treatment system 102 receive electrical power from one or more suitable laser power sources 106. In certain embodiments, the lasers 104 may also receive a cooling gas flow supplied by the gas supply system 60, as illustrated in
When power is supplied to the lasers 104, beams of laser light 108 are emitted that impinge on one or more surfaces of the continuous product 20, rapidly heating the portion 110 of the continuous product 20 impinged by the laser light 108. Since the frequency range of the laser light 108 may affect the heating of the continuous product 20, the frequency range of the laser 104 may be selected at a frequency readily absorbed by the surface of the continuous product 20 to promote heating. Further, in certain embodiments, the laser light 104 produced by the lasers 104 may be either pulsed or continuous.
For the laser thermal treatment system 102, a number of parameters may be tuned by the controller 64 to achieve the desired heating (e.g., uniform heating rate, uniform peak temperature, and/or uniform temperature distribution) when thermally treating the continuous product 20. For example, the controller 64 may monitor and control the average and peak power supplied by the power sources 106 to the lasers 104 and/or the average and peak intensity of the laser light 108 emitted by the lasers 104 to achieve the desired heating of the continuous product 20. For embodiments in which the lasers 104 are tunable, the sensors 70 may include spectral sensors and the controller 64 may monitor and control the frequency of the emitted laser light 108 based on measurements performed by the sensors 70. For embodiments in which the lasers 104 are pulsed lasers, the controller 64 may monitor and control the pulsing frequency of the emitted laser light 108. Further, it may be noted that, in certain embodiments, the controller 64 may not signal the power sources 106 to supply power to the lasers 104 until the rate of advancement of the continuous product 20 is above a threshold value, until the oxygen and/or moisture content of the atmosphere within the housing 44 is below a threshold value, or a combination thereof. In other embodiments, the controller 64 may signal the power sources 106 to gradually increase the power supplied to the lasers 104 proportionally with the gradual increase in the rate of advancement of the continuous product 20.
In certain embodiments, the desired heating may be achieved by controlling how the laser light 108 impinges on the surfaces of the continuous product 20. In certain embodiments, the positions of the lasers 104 and/or any number of beam control features (e.g., mirrors, deflectors, diffusers, lenses, filters, etc.) may be fixed, manually adjustable, or mechanically adjustable in an automated manner using actuators controlled by the controller 64. These beam control features may generally be capable of adjusting the direction, shape, and/or focus of the laser light 108. For example, in certain embodiments, the controller 64 may monitor and control the positions of the lasers 104 and/or one or more beam control features to provide the desired heating of the continuous product 20. By specific example, the controller 64 may adjust the respective distances between the lasers 104 and the surface of the continuous product 20. Additionally, the radial and/or longitudinal position of the lasers 104 with respect to the continuous product 20 may be also be adjusted to achieve the desired heating of the continuous product 20.
With the foregoing in mind,
The beams of laser light 108A and 108B illustrated in
For the embodiment illustrated in
The technical effects of the presently disclosed embodiments include the inline, rapid thermal treatment of continuous products. The presently disclosed thermal treatment systems afford numerous advantages over batch thermal treatment processes in terms of time and cost. For example, disclosed embodiments of the thermal treatment system are effective to clean organic materials from the surfaces of the continuous product, to dry the continuous product of moisture or solvent, and/or to produce phase changes or chemical reactions within or on the surface of the continuous product. Furthermore, in certain embodiments, the disclosed thermal treatment system may utilize resistive heating, plasma heating, or laser heating to uniformly heat a variety of different continuous products during thermal treatment. As such, the disclosed thermal treatment system embodiments enable the direct, inline thermal treatment of a variety of conductive or non-conductive continuous products in a cost effective manner.
While only certain features of the technique have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US2015/010919 | 1/9/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2016/111703 | 7/14/2016 | WO | A |
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Number | Date | Country | |
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20180010855 A1 | Jan 2018 | US |