Electromagnetic induction can curing oven

Abstract

A can curing oven for curing one or more coatings applied to one or more surfaces of the sidewalls of a number of can bodies includes a heating assembly with a number of induction heating units, the number of induction heating units defining a generally enclosed space, each induction heating unit capable of generating a total effective amount of received heat necessary to cure the coating on each can body. The curing oven of the present invention further includes a transport mechanism for supporting the number of can bodies and moving them along a working path that passes through the generally enclosed space between the number of induction heating units.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 105,938, filed February 6, 2023, entitled "ELECTROMAGNETIC INDUCTION CAN CURING OVEN."

[0002] <Technical field> The disclosed concepts relate to a mechanism for curing a coating on the surface of a can body, and more particularly to a mechanism for curing a coating that uses electromagnetic induction to generate the heat used for such curing. [Background technology]

[0003] Pin ovens are well known in the art and are widely used to dry / cure coatings on the exterior of open-ended partially finished beverage cans (also referred to herein as "can bodies"). Can decorators apply coatings to the exterior of cans, including, but not limited to, inks, labeling enamels, lacquer or varnish overcoats, or both printed labels and overcoats. Such ovens contain several heaters, typically natural gas heaters, that generate a heated fluid (air). That is, natural gas is burned to heat the air. The heated air is generally maintained in a heated enclosed space within which a conveyor chain travels a generally vertical, serpentine path. As a result, pin ovens occupy a large volume and have complex moving assemblies. To accommodate the conveyor chain's path long enough to cure the cans, the enclosed space is typically approximately 75 m long. 3 This is problematic because such ovens take up a lot of space within a processing facility. Additionally, conveyors that run over serpentine paths require complex mechanical assemblies to accommodate conveyor changes of direction.

[0004] The conveyor chain supports the cans with a plurality of pins. That is, a plurality of elongated carrier pins are attached and spaced along the length of the conveyor chain. Open-ended cans are placed on the extending pins and transported through the oven over a serpentine chain path. Nozzles positioned along the chain path direct heated air at the outside of the cans as they move through the enclosed space of the oven. The heated air keeps the cans on the pins and cures the coating. Because the heated air flow is configured to hold and stabilize the cans on the pins, most pin ovens continuously direct heated air at the bottom of the cans. However, the can bottoms are not typically coated. Thus, energy is lost and wasted when heated air is directed at the can bottoms.

[0005] Pin ovens operate at a temperature of approximately 420°F and are configured to operate substantially continuously. As such, they are not configured to rapidly cool or heat up. In this configuration, operators typically continue to run the pin oven heater even when the pin oven is not in use. That is, even if the flow of cans being processed is interrupted, for example, due to a malfunction of other machinery on the can processing line or scheduled maintenance, the pin oven heater operates to prevent the pin oven from cooling down. That is, operators leave the pin oven heater running rather than shutting it down and allowing the pin oven to cool below its operating temperature. Therefore, energy is wasted by the inability to rapidly heat up the pin oven.

[0006] Pin ovens use fans to move heated air and vent exhaust. With both the natural gas heater and the exhaust fan running, pin ovens are noisy, typically operating at approximately 95 dB. This is problematic. Furthermore, energy consumption is significant, both in terms of natural gas to fuel the heater and electricity to operate the exhaust fan. Therefore, reducing energy costs is crucial. Furthermore, pin ovens such as these have reached their practical limits in terms of can drying speed and throughput. Currently, pin ovens process cans at approximately 2400 cans per minute (cpm). Other can processing equipment, such as decorators, can operate at higher speeds. Thus, pin ovens have become a bottleneck on can processing lines.

[0007] Therefore, there is a need for an improved can curing oven. Summary of the Invention

[0008] These and other needs are met by at least one embodiment of the disclosed and claimed concepts, which provides a can curing oven configured to cure a coating on a surface of a sidewall of a number of can bodies. The can curing oven includes a heating assembly including a number of induction heating units sized and configured to define a generally enclosed space, the number of induction heating units configured to generate a total effective amount of received heat necessary to cure the coating on each can body, and a transport mechanism configured to support and move the number of can bodies along a working path through the generally enclosed space.

[0009] Each induction heating unit may include a heating element and an induction coil disposed around the heating element, the induction coil being configured to be coupled to a controlled AC power source.

[0010] The heating element may comprise a single C-shaped channel.

[0011] The number of induction heating units may include a plurality of induction heating units, and at least two of the plurality of induction heating units may be disposed on opposite sides of the working path.

[0012] The number of induction heating units may include a plurality of induction heating units, and at least two of the plurality of induction heating units may be positioned on one side of the working path.

[0013] The can curing oven may further include a housing that generally encloses the heating assembly.

[0014] The can curing oven may be configured to cure coatings on can bodies of a first configuration and can bodies of a second configuration, the can bodies of the first configuration being different from the can bodies of the second configuration, and the housing assembly may include an adjustable mount assembly configured to position each induction heating unit at a first position configured to provide a proportionally effective amount of heat reception to the can bodies of the first configuration and at a second position configured to provide a proportionally effective amount of heat reception to the can bodies of the second configuration.

[0015] Each induction heating unit may be a modular induction heating unit.

[0016] Each induction coil may be configured to be selectively powered by a controlled AC power source when the exterior surface of the can body is within effective distance.

[0017] The transport mechanism may include a plurality of support elements, and each support element of the plurality of support elements may be coupled to a can body and configured to support the can body.

[0018] At least one induction heating unit of the number of induction heating units may be positioned between two different portions of the working path, or between one portion of the working path and another portion of the working path along which the conveying mechanism and / or another conveying mechanism is configured to move can bodies of the number of can bodies.

[0019] Some heating units may be configured to process can bodies at maximum can decorator speed.

[0020] The transport mechanism may be configured to support and move a number of can bodies along a linear working path through a generally enclosed space.

[0021] The transport mechanism may be configured to support and move a number of can bodies along a non-linear working path through a generally enclosed space.

[0022] Another embodiment of the disclosed and claimed concepts provides a method for curing a coating on a surface of a sidewall of each of a number of can bodies, the method including providing a number of can bodies adjacent a number of induction heating units and energizing the number of induction heating units to produce a total effective amount of received heat necessary to cure the coating on the exterior surface of the sidewall of each of the number of can bodies.

[0023] Each induction heating unit may include a heating element and an induction coil disposed around the heating element, and powering several induction heating units may include selectively supplying AC power to the induction coil.

[0024] Powering the number of induction heating units to generate a total effective amount of heat reception may include powering the number of induction heating units from an unpowered state when an outer surface of one of the number of can bodies is within an effective distance from one of the number of induction heating units.

[0025] Providing a number of can bodies adjacent to a number of induction heating units may include providing a number of can bodies adjacent to the number of induction heating units via a transfer mechanism.

[0026] Powering the number of induction heating units to generate a total effective amount of received heat may include powering the number of induction heating units from an unpowered state when an outer surface of one of the number of can bodies is within the effective distance from one of the number of induction heating units, and returning the number of induction heating units to an unpowered state when an outer surface of another of the number of can bodies is out of the effective distance from one of the number of induction heating units.

[0027] Providing the number of can bodies adjacent to the number of induction heating units may include providing the number of can bodies along a linear work path adjacent to the number of induction heating units.

[0028] These and other objects, features, and properties of the disclosed concepts, as well as the method of operation and function of the associated elements of construction, and the combination of parts and economies of manufacture, will become more apparent from a consideration of the following description and appended claims, taken in conjunction with the accompanying drawings, all of which form a part of this specification, and in which like reference numerals indicate corresponding parts in the various views, it being expressly understood, however, that the drawings are provided for purposes of illustration and description only and are not intended as a definition of the limits of the concepts. [Brief explanation of the drawings]

[0029] The invention can be best understood from the following description of the preferred embodiment when read in conjunction with the accompanying drawings.

[0030] [Figure 1] FIG. 1 is a partially schematic perspective view of a decorator system according to an exemplary embodiment of the disclosed concepts.

[0031] [Figure 2] FIG. 2 is a partially schematic cross-sectional view of a can body according to an exemplary embodiment of the disclosed concepts.

[0032] [Figure 3] 3 is a cross-sectional view, partially schematic, of the heating mechanism of the can curing oven of the decorator system of FIG. 1 taken along line 3-3 of FIG. 1. FIG.

[0033] [Figure 4] FIG. 4 is a partially schematic perspective view of an induction heating unit of a heating mechanism according to an exemplary embodiment of the disclosed concepts.

[0034] [Figure 5] FIG. 5 is a partially schematic cross-sectional view similar to FIG. 3 of a heating mechanism of a can curing oven in a first configuration according to another exemplary embodiment of the disclosed concepts.

[0035] [Figure 6] FIG. 6 is a partially schematic cross-sectional view of the heating mechanism of FIG. 5 in a second configuration. DETAILED DESCRIPTION OF THE INVENTION

[0036] It is understood that the specific elements illustrated in the drawings and described in the following description are merely exemplary embodiments of the disclosed concepts and are offered as non-limiting examples for purposes of illustration only. As such, specific dimensions, orientations, assembly, number of components used, configurations of embodiments, and other physical characteristics of the embodiments disclosed herein should not be considered limitations on the scope of the disclosed concepts.

[0037] Directional terms used herein, such as clockwise, counterclockwise, left, right, up, down, above, below, and derivatives thereof, relate to the orientation of the elements as shown and do not limit the claims unless expressly stated herein.

[0038] As used herein, the singular forms "a" and "the" include the plural forms unless the context clearly dictates otherwise.

[0039] As used herein, "configured to [verb]" means that the specified element or assembly has a structure that is shaped, sized, arranged, coupled, and / or configured to perform the specified verb. For example, a member "configured to move" may be operably coupled to another element and include an element that moves that member, or the member is otherwise configured to move in response to another element or assembly. Thus, as used herein, "configured to [verb]" describes structure, not function. Furthermore, as used herein, "configured to [verb]" means that the specified element or assembly is intended and designed to perform the specified verb. Thus, an element that is merely capable of performing the specified verb, but is not intended and designed to perform the specified verb, is not "configured to [verb]."

[0040] As used herein, "associated" means that elements are part of the same assembly and / or work together or interact in some way. For example, an automobile has four tires and four hubcaps. Although all elements are connected to parts of the automobile, each hubcap is understood to be "associated" with a particular tire.

[0041] As used herein, a "coupling assembly" includes two or more couplings or coupling components. The components of a coupling or coupling assembly are generally not part of the same element or other elements. Thus, the components of a "coupling assembly" may not be described simultaneously in the following description.

[0042] As used herein, a "coupling" or "coupling component" refers to one or more components of a coupling assembly. That is, a coupling assembly includes at least two components configured to be coupled to one another. The components of a coupling assembly are understood to be compatible with one another. For example, in a coupling assembly, if one coupling component is a snap socket, the other coupling component is a snap plug; if one coupling component is a bolt, the other coupling component is a nut or a screw hole. Furthermore, the passages of the elements are part of the "coupling" or "coupling component." For example, in an assembly in which two wooden boards are joined by a nut and a bolt that extend through their passages, the nut, the bolt, and the two passages are the "coupling" or "coupling component," respectively.

[0043] As used herein, the expression "coupled" between two or more parts or components means that the parts are joined or move together directly or indirectly, i.e., through one or more intermediate parts or components, to the extent that a link occurs. As used herein, "directly coupled" means that two elements are in direct contact with each other. As used herein, "fixedly coupled" or "fixed" means that two components are coupled so that they move while maintaining a constant orientation relative to each other. As used herein, "adjustably fixed" means that two components are coupled so that they move as one while maintaining a constant overall orientation or position relative to each other, and can move within a limited range or around one axis. For example, a doorknob is "adjustably fixed" relative to a door; while the doorknob can rotate, it is typically fixed in one position relative to the door. Furthermore, the cartridge (nib and ink tank) of a retractable pen is "adjustably fixed" relative to the housing; the cartridge moves between a retracted position and an extended position, but its orientation relative to the housing is generally maintained. Thus, when two elements are coupled, all parts of those elements are coupled. However, a statement that a particular portion of a first element is coupled to a second element, e.g., that a first end of an axle is coupled to a first wheel, means that the particular portion of the first element is located closer to the second element than other portions of the first element. Furthermore, an object that is held in place on another object solely by gravity is not "coupled" to the object below unless the upper object is otherwise held substantially in place. That is, for example, a book on a table is not coupled to the table, but a book glued to the table is coupled to the table.

[0044] As used herein, the phrases "removably coupled" or "temporarily coupled" mean that one component is substantially temporarily coupled to another component. That is, two components are coupled such that joining or separating the components is easy and does not damage the components. For example, two components secured together with a limited number of easily accessible fasteners, i.e., fasteners that are not difficult to access, are "removably coupled," whereas two components joined by welds or fasteners that are difficult to access are not "removably coupled." A "difficult to access fastener" is a fastener that requires the removal of one or more other components before accessing the fastener; the "other components" are not access means, such as, but not limited to, a door.

[0045] As used herein, "operably coupled" means that elements or assemblies that are movable between a first position and a second position or configuration are coupled such that the first element moves from one position / configuration to the other and the second element moves between both positions / configurations. Note that a first element may be "operably coupled" to another element, not vice versa.

[0046] As used herein, the expression that two or more parts or components "engage" each other means that the elements exert a force or bias on each other, either directly or through one or more intermediate elements or components. Furthermore, with respect to moving parts, as used herein, the moving part may "engage" another element while moving from one position to another and / or may "engage" another element once it reaches a recited position. Thus, "element A engages element B when moved to its first position" and "element A engages element B when in its first position" are equivalent expressions and are understood to mean that element A engages element B while moving to its first position and / or while in its first position.

[0047] As used herein, "operably engage" means "engage and move." That is, when used with respect to a first component configured to move a second, movable or rotatable component, "operably engage" means that the first component applies a force sufficient to move the second component. For example, a screwdriver can be placed in contact with a screw. When no force is applied to the screwdriver, the screwdriver is merely "temporarily coupled" to the screw. When an axial force is applied to the screwdriver, the screwdriver presses against the screw and "engages" the screw. However, when a rotational force is applied to the screwdriver, the screwdriver "operably engages" the screw and turns it. Furthermore, in the context of electronic components, "operably engage" means that one component controls another component via a control signal or current.

[0048] As used herein, "corresponding" indicates that two structural components have a similar size and shape to one another and can be joined with a minimal amount of friction. Thus, an opening that "corresponds" to a member has a size slightly larger than the member so that the member can pass through the opening with a minimal amount of friction. This definition is modified when two components are a "tight" fit. In such a situation, the difference in dimensions between the components is further reduced, increasing the amount of friction. If the elements defining the opening and / or the components inserted into the opening are made from a deformable or compressible material, the opening may be slightly smaller than the components inserted into the opening. With respect to surfaces, shapes, and lines, two or more "corresponding" surfaces, shapes, or lines have approximately the same size, shape, and contour.

[0049] As used herein, a "path of travel" or "path," when used in reference to a moving element, includes the space through which the element travels during movement. Thus, a moving element inherently has a "path of travel" or "path." Furthermore, a "path of travel" or "path" relates to the overall movement of one identifiable structure relative to another object. For example, assuming a perfectly smooth road, the rotating wheels of a car (an identifiable structure) move very little relative to the body of the car (another object). That is, the wheel as a whole does not change position relative to, for example, an adjacent fender. Thus, the rotating wheel does not have a "path of travel" or "path" relative to the body of the car. Conversely, the air intake valve (an identifiable structure) of that wheel does have a "path of travel" or "path" relative to the body of the car. That is, while the wheel rotates and moves, the entire intake valve moves relative to the body of the car.

[0050] As used herein, the term "unitary" refers to a component that is made as a single piece or unit. That is, a component that includes multiple pieces that are made separately and then joined together as a unit is not a "unitary" component or structure.

[0051] As used herein, the term "some" means one or more integers (i.e., a plurality). Thus, for example, the phrase "some elements" means one element or more than one element. Note specifically that "some [x]" includes a single [x].

[0052] As used herein, in the phrases "[x] moves between a first position and a second position" or "[y] is configured to move [x] between a first position and a second position," "[x]" is the name of an element or assembly. Furthermore, when [x] is an element or assembly that moves between multiple positions, the pronoun "the" refers to "[x]," i.e., the element or assembly referred to after the pronoun "the."

[0053] As used herein, a "radial side / surface" of a circular or cylindrical body is a side / surface that extends around or surrounds its center or a height line passing through its center. As used herein, an "axial side / surface" of a circular or cylindrical body is a surface that extends in a plane that extends approximately perpendicular to a height line passing through the center of the cylinder. That is, generally, in the case of a cylindrical soup can, the "radial side / surface" is the approximately circular sidewall, and the "axial side / surface" is the top and bottom of the soup can. Furthermore, as used herein, "extending radially" means extending in a radial direction or extending along a radial line. That is, for example, a "radially extending" line extends from the center of the circle or cylinder toward the radial side / surface. Furthermore, as used herein, "extending axially" means extending in an axial direction or extending along an axial line. That is, for example, an "axially extending" line extends from the bottom of the cylinder to the top of the cylinder, generally parallel to the central longitudinal axis of the cylinder.

[0054] As used herein, "substantially curvilinear" refers to an element having multiple curved portions, a combination of curved and flat portions, or multiple flat portions or segments that are angled relative to one another to form a curve.

[0055] As used herein, a "plate" or "plate-like member" is a generally thin element that includes opposed, broad, generally parallel surfaces, i.e., the plane of the plate, and narrower end faces extending between the broad, parallel surfaces. That is, as used herein, it is essential that a "plate-like" element has two opposed planar surfaces. The periphery, and thus the end faces, may include generally straight portions, as in the case of a rectangular plate-like member, or may be curved, as in the case of a disk, or may have any other shape.

[0056] As used herein, "upwardly depending" means an element that extends generally perpendicularly upward from another element.

[0057] As used herein, the terms "can" and "container" are used substantially interchangeably to refer to any known or suitable container configured to contain contents (e.g., without limitation, liquid, food, or other suitable substance), and expressly include, without limitation, beverage cans such as beer and soda cans, as well as food cans.

[0058] As used herein, a "can body" has a base and a depending or upwardly depending sidewall. The "can body" is one piece. In this configuration, the "can body" defines a generally closed space. Thus, the "can body," i.e., the bottom and sidewall, also includes the outer and inner surfaces. Thus, for example, the "can body" includes the inner sidewall surface and the outer sidewall surface.

[0059] As used herein, "centered" in phrases such as "disposed about [element, point, or axis]," or "extends about [element, point, or axis]," or "[X] degrees centered about [element, point, or axis]," means surrounding, extending, or measured about. When used in connection with a measurement or in similar contexts, "about" means "approximately," i.e., an approximate range for the measurement as would be understood by one of ordinary skill in the art.

[0060] As used herein, an "elongate" element essentially comprises a longitudinal axis and / or a longitudinal line extending in the direction of extension.

[0061] As used herein, "generally" means "in a typical manner" in relation to the term it modifies, as would be understood by a person of ordinary skill in the art.

[0062] As used herein, "substantially" means "mostly" in relation to the term it modifies, as understood by one of ordinary skill in the art.

[0063] As used herein, "at" means at and near the location in relation to the modified term, as understood by one of skill in the art.

[0064] A partial schematic diagram of a decorator system 10 according to one exemplary embodiment of the disclosed concepts is shown in FIG. 1. The decorator system 10 is configured to apply a coating to a can body 1 and subsequently cure the coating. In the exemplary embodiment shown in FIG. 2, the can body 1 is generally cylindrical and includes a base 2, a sidewall 3, and an upper opening 4 opposite the base 2 and defined by an upper portion (not numbered) of the sidewall 3. As described above, the can body 1 has an inner surface and an outer surface; thus, the sidewall 3 of each can body 1 has an outer surface 5 and an inner surface 6. Furthermore, the generally cylindrical can body 1 has a longitudinal axis 7 extending through the center of the base 2 and the upper opening 4, around which the sidewall 3 is disposed. The aforementioned coating (not shown) is typically applied to the outer surface 5 of the sidewall 3 of the can body 1, but may also be applied to the inner surface 6 depending on the particular application.

[0065] Referring again to FIG. 1 , the decorator system 10 generally includes a decorator assembly 12 (shown diagrammatically) and a can curing oven 20. As is known, the decorator assembly 12 is configured to apply one or more coatings to one or more regions of the can body 1. Furthermore, as is known, the decorator assembly 12 is configured to process in excess of 2400 cans per minute (hereinafter "cpm"). The decorator assembly speed (cpm) is herein referred to as the "can decorator speed." Thus, as used herein, a "maximum can decorator speed" is a speed greater than 2400 cpm. As is known, applied coatings include, but are not limited to, inks, paints, varnishes, and lacquers. The decorator system 10 further includes a transfer assembly 14 (also shown diagrammatically), which may be provided separately from or as part of the decorator assembly 12. The transfer assembly 14 is configured to move the coated, but not yet cured, can bodies 1 one at a time from the decorator assembly 12 to a can curing oven 20 .

[0066] The can curing oven 20 includes a transport mechanism 30 and a heating assembly 40. A housing assembly (not shown) may enclose substantially all or selected portions of the can curing oven 20 and / or the decorator system 10. The transport mechanism 30 may be any device suitable for supporting and moving several can bodies 1 through a space 32 generally defined / enclosed by portions of the heating assembly 40, as described below. In the embodiment shown in FIG. 1 , the transport mechanism 30 is shown schematically as a conveyor mechanism that moves a plurality of can bodies 1 along a linear working path (partially shown schematically by the row of can bodies 1 extending into the space 32 from the end adjacent the transfer mechanism 14). In the exemplary embodiment, the transport mechanism 30 includes a chain with can body support pins similar to those used in a typical pin oven. This example is provided for illustrative purposes only, and it should be understood that the structure of the transport mechanism 30 and its components may be modified without altering the scope of the disclosed concepts. It should also be understood that the conveying mechanism 30 may be configured to move the can body 1 along a non-linear (e.g., but not limited to, curved, serpentine, etc.) working path without departing from the scope of the disclosed concepts.

[0067] In one exemplary embodiment of the disclosed concepts, the can curing oven 20, and more specifically, its transport mechanism 30, is configured to have an operating speed corresponding to the maximum can decorator speed (described above). As used herein, "operating speed" refers to the speed (in cpm) of the assembly while it is in operation, not the speed that can be achieved when the assembly is not in operation. That is, for example, the transport mechanism 30 has a maximum operating speed when it moves can bodies 1 as the coating is cured. However, the transport mechanism 30 may move faster when the can bodies 1 are not obstructing it. Such non-"operating speeds" are not relevant to this application. In the exemplary embodiment, the transport mechanism 30 moves can bodies 1 at a speed equal to the maximum can decorator speed. As will be seen further below, embodiments of the disclosed concepts adjust (e.g., lengthen) the overall length of the work path within the can curing oven 20 to accommodate faster decorator speeds.

[0068] Continuing with the cross-sectional views of FIGS. 1 and 3 , the heating assembly 40 includes several induction heating units 42 sized and configured to generally define / enclose the space 32 through which the multiple can bodies 1 move via the conveying mechanism 30. As used herein, an "induction heating unit" is a device that generates heat from an element disposed within an alternating magnetic field. In the example shown in FIGS. 1 and 3 , the multiple induction heating units 42 are positioned / distributed on both sides of the working path along which the conveying mechanism 30 moves the multiple can bodies 1. In such a configuration, the induction heating units 42 on each side of the working path are arranged end-to-end to provide a sufficient length of the working path to allow sufficient residence time for curing the coating applied to the can bodies 1 passing therethrough. As noted above, the heating units 42 may have one or more different (e.g., non-linear) shapes, thus defining a non-linear path and / or a multi-tiered arrangement to meet the spatial requirements of a particular application.

[0069] Referring to FIG. 4 in addition to FIG. 3, each induction heating unit 42 of the heating assembly 40 includes a heating element 44 that is selectively activated, i.e., radiates heat, by selectively applying an AC magnetic field. In the example shown schematically in FIGS. 3 and 4, the heating element 44 is an elongated C-channel member formed from steel or other suitable material. Preferably, the heating element 44 is provided as a commercially available item (e.g., a C-channel, an angle, an I-beam, a flat bar, etc.) or is formed from a bent / folded sheet of material. In either case, the heating element 44 is formed from an iron-based (or other suitable) material, and when placed in an AC magnetic field, eddy currents are generated, thereby appropriately heating the heating element 44, as described in more detail below. In the example shown in FIGS. 3 and 4, the AC magnetic field is applied to each heating element 44 by an induction coil 46 disposed around the heating element 44 and selectively powered by an AC power source 48. As is well known, placing a conductive material, i.e., the heating element 44, in such an alternating magnetic field results in two heating effects in the material: hysteresis loss, which only occurs in magnetic materials such as iron, nickel, and cobalt; this occurs because friction occurs between molecules when the material is continuously magnetized in different directions; the higher the frequency of the magnetic field oscillation, the faster the particles move, increasing friction and, consequently, heat generation; and eddy current loss, which occurs as a Joule heating effect in any conductive material due to electrical currents induced by the fluctuating magnetic field. The induction coil 46 is formed from one or more conductors 50 wound around the heating element 44 without being electrically connected to it.

[0070] The number of induction heating units 42 is configured to generate a total effective amount of received heat. As used herein, "total effective amount of received heat" (or "total effective amount of received radiant heat") refers to heat (or radiant heat) received at or by the can body 1 that is sufficient to cure the coating on the can body 1, but does not substantially exceed the minimum amount necessary to cure the coating on the can body 1. Thus, after each of the number of can bodies 1 passes through the heating assembly 40 of the can curing oven 20, the coating thereon is cured, and each can body 1 is ready for further processing. As used herein, "received heat" (or "received radiant heat") refers to energy (i.e., radiant energy) received at or by the can body 1. It is understood that "heat reception" is dependent upon several variables, including, but not limited to, the energy output of the heating assembly 40, the distance between each induction heating unit 42 of the multiple induction heating units 42 and the can body 1 as the can body 1 passes through it, and the duration or amount of time the can body 1 is exposed to the heat and / or heating unit 42. It is understood that one skilled in the art would readily understand / know how to adjust such variables to determine the desired configuration of the can curing oven 20.

[0071] As described below, in one exemplary embodiment, the can curing oven 20 is optimized for speed (measured in cpm). Additionally, in other embodiments, the can curing oven 20 is optimized for size, energy efficiency, and / or economic efficiency. Each configuration requires optimization of multiple variables. Furthermore, a single induction heating unit 42 is configured to generate a "proportionally effective amount of received heat." As used herein, "proportionally effective amount of received heat" refers to a portion of the "total effective amount of received heat" generated by a single induction heating unit 42 of the heating assembly 40. Several induction heating units 42 are configured to generate a total effective amount of radiant heat. That is, the radiant heat generated by several induction heating units 42 is sufficient to cure the coating on the can body 1.

[0072] In exemplary embodiments of the disclosed concepts, the induction heating units 42 may be modular heating units. In other words, induction heating units 42 may be added, removed, or rearranged manually or via suitable automated or semi-automated configurations to adjust from a first configuration for hardening can bodies 1 to a second configuration for hardening a particular can body 1'. For example, as shown in the exemplary configuration of FIG. 3, one or more actuators 52 or adjustable mounting assemblies may be provided to selectively adjust the spacing between the induction heating units 42 to accommodate can bodies 1 with different diameters d. Meanwhile, FIGS. 5 and 6 illustrate an exemplary embodiment of a heating assembly 40' that operates similarly to the induction heating unit 42 but employs induction heating units 42' and 42'' to accommodate can bodies 1, 1' with different heights h, h' (and / or different diameters). For example, to move from the first configuration of FIG. 5 to the possible second configuration of FIG. 6, the pair of upper induction heating units 42' shown would be moved vertically upward (relative to the arrangement shown in the figure) and an additional induction heating unit 42" would be positioned vertically between the pair of upper and lower induction heating units 42' to arrive at the arrangement shown in FIG. 6. Furthermore, such an arrangement of induction heating units 42' and 42" can be adjusted similarly to FIG. 3 to accommodate can bodies with different diameters d. It should be understood that such positioning / repositioning of the induction heating units may be accomplished either manually or via any suitable actuator 52 or other suitable arrangement without departing from the scope of the disclosed concepts.

[0073] It should be appreciated that because the heating elements 44 of each heating unit 42 radiate heat all around it, not just from the sides, in some exemplary embodiments, several heating units 42 may be used to heat can bodies 1 passing by one or more of their sides (e.g., can bodies 1 move along multiple parallel working paths with heating units 42 or rows thereof positioned between them). In embodiments where such substantially omnidirectional radiant heat is undesirable, a coating or shield may be used to limit heat from the heating elements 44 in undesired directions.

[0074] In one embodiment, the induction heating unit 42 is configured to fully start up within minutes. As used herein, "fully start up" means that the unit becomes hot enough to cure the coating on the can body. This means that the induction heating unit 42, located in close proximity to the can body 1, can begin heating the can body 1 much more quickly, unlike a hot air convection oven, which must heat a larger enclosed space inside. This solves the problems discussed above. Furthermore, the induction heating unit 42 is less noisy than a hot air convection oven. In an exemplary embodiment, the fanless can curing oven 20 generates noise levels between approximately 10 dB and 20 dB, or approximately 15 dB. As used herein, a noise level between approximately 10 dB and 20 dB is a "reduced noise level." As used herein, a noise level of approximately 15 dB is a "specified reduced noise level." The can curing oven 20 generates a reduced noise level, or a specified reduced noise level, thereby solving the problems discussed above. Furthermore, as noted above, if the can curing oven 20 uses a fan, the curing oven 20 generates between about 70 dB and 80 dB, or about 75 dB, which is still less noise than prior art curing ovens and solves the problems described above.

[0075] In one embodiment, the can curing oven 20 is optimized for speed. That is, as noted above, it is desirable for the curing oven's intake rate to be equal to the decorator assembly 12 discharge rate. In an exemplary embodiment, the decorator assembly 12 intake rate, and therefore the can curing oven 20 intake rate, is approximately 2400 cpm. Furthermore, as noted above, other variables that affect the curing of the coating on the can body 1 include, but are not limited to, the energy output of the heating assembly 40, the distance between the induction heating unit 42 and the can body 1, and the time the can body 1 is exposed to the heat and / or induction heating unit 42. Furthermore, the size of the enclosed space 32 is also dependent on these variables. It is further understood that, of these variables, only the output of the heating assembly 40 is limiting. That is, temperatures above approximately 220°C (428°F) are detrimental to the can body 1. Accordingly, in certain embodiments, the heating assembly 40 also includes an air blower assembly 60 configured to remove heated air from the enclosed space 32 and / or the housing mechanism surrounding the heating mechanism 30. The air blower assembly 60 is configured to reduce the amount of heat within the enclosed space 32 and / or said housing mechanism.

[0076] While specific embodiments of the disclosed concepts have been described in detail, those skilled in the art will recognize that various modifications and substitutions to those details may be made in light of the overall teachings of the present disclosure. Accordingly, the particular configurations disclosed are intended to be illustrative only and not limiting on the scope of the invention, which is given the full scope of the appended claims and any and all equivalents thereof.

[0077] In the claims, reference signs placed in parentheses shall not be construed as limiting the claim. The word "comprises" or "includes" does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word "a" or "an" preceding an element does not exclude the presence of several such elements. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in different dependent claims does not indicate that these elements cannot be used in combination.

Claims

1. a can curing oven 20 configured to cure a coating on the sidewall surface of each can body 1 of several can bodies; a heating assembly (40) including several induction heating units (42) sized and configured to define a substantially enclosed space (32), the several induction heating units configured to generate a total effective amount of received heat necessary to cure the coating on each can body; a conveying mechanism 30 configured to support the several can bodies 1 and move them along a working path through the substantially enclosed space; A can curing oven is provided.

2. Each induction heating unit 42 is a heating element 44; and an induction coil 46 disposed around the heating element, the induction coil configured to be coupled to a controlled AC power source 48; 10. The can curing oven of claim 1, comprising:

3. 3. The can curing oven of claim 2, wherein the heating element comprises a single C-shaped channel.

4. the number of induction heating units includes a plurality of induction heating units; The can curing oven of claim 1 , wherein at least two of the plurality of induction heating units are disposed on opposite sides of the working path.

5. the number of induction heating units includes a plurality of induction heating units; The can curing oven of claim 1 , wherein at least two of the plurality of induction heating units are disposed on one side of the work path.

6. The can curing oven of claim 1 further comprising a housing generally enclosing said heating assembly.

7. the can curing oven is configured to cure coatings on can bodies of a first configuration and can bodies of a second configuration, the can bodies of the first configuration being different from the can bodies of the second configuration; the housing assembly includes an adjustable mount assembly; The adjustable mount assembly mounts each induction heating unit to: a first position, wherein each induction heating unit is configured to produce a proportionally effective amount of heat reception to the can body in the first configuration; a second position, wherein each induction heating unit is configured to provide a proportionally effective amount of heat reception to the can body in the second configuration; 10. The can curing oven of claim 1, configured to be placed in a

8. 10. The can curing oven of claim 1, wherein each induction heating unit is a modular induction heating unit.

9. 3. The can curing oven of claim 2, wherein each induction coil is configured to be selectively powered by a controlled AC power source when the outer surface of the can body is within effective distance.

10. the transport mechanism includes a plurality of support elements; 2. The can curing oven of claim 1, wherein each of the plurality of support elements is configured to be coupled to and support one of the several can bodies.

11. 2. The can curing oven according to claim 1, wherein at least one induction heating unit of the number of induction heating units is arranged between two different portions of the working path or between a portion of the working path and a portion of another working path along which the conveying mechanism and / or another conveying mechanism is configured to move can bodies of the number of can bodies.

12. 10. The can curing oven of claim 1, wherein the several heating units are configured to process can bodies at a maximum can decorator speed.

13. 2. The can curing oven of claim 1, wherein the transport mechanism is configured to support and move the number of can bodies along a linear working path through the substantially enclosed space.

14. 2. The can curing oven of claim 1, wherein the transport mechanism is configured to support and move the number of can bodies along a non-linear working path through the generally enclosed space.

15. 1. A method for curing a coating on an exterior surface of a sidewall of each of several can bodies, comprising: providing a number of said can bodies adjacent to a number of induction heating units; energizing the number of induction heating units to produce a total effective amount of received heat necessary to cure the coating on the exterior surface of the sidewall of each of the number of can bodies; A method comprising:

16. Each induction heating unit is A heating element; an induction coil disposed around the heating element; It is equipped with 16. The method of claim 15, wherein powering the several induction heating units comprises selectively supplying AC power to an induction coil of each induction heating unit.

17. The method wherein powering the number of induction heating units to generate the total effective amount of heat received includes powering the number of induction heating units from an unpowered state when an outer surface of one of the number of can bodies is within an effective distance from one of the number of induction heating units.

18. 16. The method of claim 15, wherein providing the number of can bodies adjacent to the number of induction heating units comprises providing a plurality of can bodies adjacent to the number of induction heating units via a transfer mechanism.

19. Powering the several induction heating units to produce the total effective amount of heat received comprises: When an outer surface of one of the can bodies is within an effective distance from one of the induction heating units, supplying power to the induction heating units from an unpowered state; When an outer surface of another of the plurality of can bodies is out of an effective distance from one of the plurality of induction heating units, returning the plurality of induction heating units to the non-powered state; 20. The method of claim 18, comprising:

20. 16. The method of claim 15, wherein providing the number of can bodies adjacent the number of induction heating units includes providing the number of can bodies along a linear work path adjacent the number of induction heating units.

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