Systems and methods for coating removal

Abstract

A system (100) for removing a coating from a substrate (108) includes at least one induction head (102) electrically connected to a power source (103), where the power source (103) and the induction head (102) are configured to deliver energy to the coating (106) at an energy density level equal to or greater than the incineration threshold of the coating. The system also includes a vacuum system (110) configured to extract at least a portion of the coating (106), including incineration products generated by delivering energy to the coating. The system may further include a laser system (116) configured to pyrolytically ablate or burn a residual layer (118) of the coating on the substrate (108), and a second vacuum system (120) configured to extract products (122) generated by the laser treatment. Also claimed is a method (500) for coating removal that includes an induction heating step (504), a first vacuum stage (510), a laser ablation step (512), and a second vacuum stage (514).

Description

[Technical Field]

[0001] REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 545,177, filed October 21, 2023, and to U.S. Provisional Application No. 63 / 560,966, filed March 4, 2024, both of which are incorporated by reference in their entireties.

[0002] The present disclosure relates generally to systems and methods for removing coatings from metals, including situations where the coating contains one or more hazardous substances. The disclosed systems may use thermal induction and / or pulsed laser ablation in combination with waste removal techniques to provide a coating removal solution that eliminates consumable media such as those used with abrasive blast cleaning. [Background technology]

[0003] Removing coatings from metal structures can be a difficult task. Current methods include compressed air blast cleaning, which involves blowing small particles of abrasive material (such as sand, steel grit, or glass beads) mixed with air onto a surface to remove the coating. Abrasive blast cleaning produces high noise levels and produces large amounts of dust and waste consisting of used abrasive blast media mixed with the removed coating material. Additionally, compressed air equipment can easily consume hundreds of gallons of fuel each day.

[0004] Other methods for removing coatings include vacuum blast cleaning, wet abrasive blast cleaning, chemical cleaning, hand scraping, and heat gun coating removal. Like abrasive blast cleaning, each of these processes can release harmful airborne particulate matter, requiring complex containment equipment. In addition to the need for dust containment, abrasive blast cleaning generates a significant waste stream. For example, removing 15 mils of existing paint typically requires at least 5 pounds of abrasive media per square foot. Thus, even a small maintenance project with a surface area of ​​approximately 1,000 square feet may require 5,000 pounds (or more) of blast media to remove 15 mils of coating from that surface area. Furthermore, if the removed coating contains hazardous components such as lead, all 5,000 pounds of used media is considered hazardous mixed waste, which must be collected and disposed of in accordance with hazardous waste disposal regulations at significant cost. In a typical operation, abrasive blast waste is disposed of in drums weighing approximately 500 pounds each. In the small maintenance project example mentioned above, 5,000 pounds of mixed hazardous waste would require at least 10 drums, which could result in significant disposal and handling costs. On large bridge projects where coatings will be removed from thousands of square feet of surface area, abrasive blast waste disposal can be a significant project cost as well as an environmental hazard.

[0005] Alternative solutions to blast cleaning may include the use of thermal induction techniques to aid in the removal of paint, powder, or varnish coatings from metal substrates. These techniques rely on heating the substrate through the application of electrical energy to generate eddy currents within the substrate. While these techniques have been useful in helping loosen thick coating materials (greater than 0.5 mm) on metal substrates, traditional induction systems require additional surface pretreatment to address residual material, rust, and contaminants left on the substrate after the induction process. Furthermore, hazardous coatings loosened by traditional induction techniques may require many of the expensive airborne vapor and residue containment systems described above to properly and safely collect and dispose of the hazardous coating material once it is scraped or otherwise removed from the substrate.

[0006] Pulsed laser ablation is another alternative to abrasive blast cleaning for removing thin coatings such as rust, grease, and oil. This method ablates the coating through energy transfer from a laser. Despite its effectiveness, laser ablation can be time-consuming and not cost-effective for removing thick coating layers (greater than 0.5 mm). However, laser ablation is highly effective at removing residual coating material as well as rust and other contaminants that cannot be removed by traditional induction techniques alone.

[0007] Furthermore, as previously mentioned, the coating removal process becomes even more complicated when the coating to be removed contains hazardous materials, such as lead, chromium, and cadmium-based pigments, which are often found in paints used to paint metal structures such as bridges. Removing such coatings can involve complex operations that pose safety, health, sanitation, and environmental risks. Currently, removing hazardous coatings requires complex and expensive hazardous material containment processes. For example, the current process for removing lead-based coatings from bridges requires an SSPC Guide 6 Class 2A containment system (high level of emission control). Similarly, the current process for removing zinc-based primers / coatings from bridges requires an SSPC Class 3A containment system (moderate level of emission control). Installing containment systems is an expensive and complex operation that often results in deferred or piecemeal bridge maintenance. Even when zone or spot repainting of bridge elements is available as an alternative to repainting the entire structure, installing containment systems to manage waste associated with abrasive blast cleaning (which is also required for zone or spot treatment) often makes such partial maintenance projects cost-prohibitive. As a result, maintenance is often deferred, whereby the cost of containment can be included in the cost of recoating the entire bridge.

[0008] Handling hazardous coatings requires additional infrastructure beyond containment systems, such as a decontamination trailer with two separate rooms with clean and dirty floors to comply with health, safety, and hygiene regulations, as well as extensive and expensive personal protective equipment (PPE).

[0009] The present disclosure describes solutions that aim to alleviate or overcome one or more of the aforementioned problems. Summary of the Invention

[0010] In one embodiment, a system for coating removal is disclosed. The system may include at least one induction head. The at least one induction head may be electrically connected to a power source, where the power source and the at least one induction head are configured to deliver energy to the coating at an energy density level above an incineration threshold of the coating. The system may also include a vacuum system configured to extract at least a portion of the coating, including incineration products produced by the delivery of energy to the coating.

[0011] In another embodiment, a system for coating removal is disclosed. The system may include at least one induction head. The at least one induction head may be electrically connected to a power source, where the power source and the at least one induction head are configured to deliver energy to the coating at an energy density level equal to or greater than the incineration threshold of the coating. The system may also include a vacuum system configured to extract at least a portion of the coating, including incineration products generated by the delivery of energy to the coating. The system may also include a laser system configured to pyrolytically ablate or burn a residual layer of the substrate, and a vacuum system configured to extract products generated by the ablation or pyrolysis of the residual layer of the coating.

[0012] In another embodiment, a method for coating removal is disclosed. The method may include using an induction system configured to deliver energy to a coating at an energy density level at or above a combustion threshold of the coating, performing a vacuum stage to extract at least a portion of the coating including burn products produced by the delivery of energy to the coating, using a laser system configured to pyrolytically ablate or burn a residual layer of the substrate, and performing a vacuum stage to extract products produced by the ablation or pyrolysis of the residual layer of the coating.

[0013] The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the scope of the claims. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an illustrative block diagram of a system for removing a coating from a substrate, in accordance with an exemplary disclosed embodiment. [Figure 2A] 1 provides a schematic diagram of a system for removing a coating from a substrate, according to an exemplary disclosed embodiment; [Figure 2B] 1 provides a schematic diagram of a system for removing a coating from a substrate, according to an exemplary disclosed embodiment; [Figure 2C] 1 provides a schematic diagram of a system for removing a coating from a substrate, according to an exemplary disclosed embodiment; [Figure 2D] 1 provides a schematic diagram of a system for removing a coating from a substrate, according to an exemplary disclosed embodiment; [Figure 3] 1 provides an exemplary flow diagram of a method for removing a coating from a substrate, according to an exemplary disclosed embodiment. [Figure 4A] 1 illustrates a vacuum nozzle according to an exemplary disclosed embodiment. [Figure 4B] 1 illustrates a vacuum nozzle according to an exemplary disclosed embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several exemplary embodiments are described herein, modifications, adaptations, and other implementations are possible. For example, substitutions, additions, or modifications may be made to the components illustrated in the drawings, and the exemplary methods described herein may be modified by substituting, rearranging, deleting, or adding steps to the disclosed methods. Therefore, the following detailed description is not limited to the disclosed embodiments and examples. Instead, the appropriate scope is defined by the appended claims.

[0016] Embodiments consistent with the present disclosure provide systems and methods for removing coatings from metal substrates. For example, the disclosed systems and techniques provide a media-free alternative to abrasive blast cleaning that uses the application of energy and laser light to remove coatings from surfaces. Advantageously, these systems and processes may provide a solution for removing coatings containing harmful components without the need for dust containment, media collection, and disposal. As a result, the disclosed systems and processes may avoid the generation of large amounts of hazardous mixed waste, such as used abrasive blasting media combined with lead and other heavy metals, that often results from abrasive blasting techniques. Instead, the disclosed systems and processes seek to limit the generated waste to vaporized coating residues that can be more easily collected and disposed of without the need for expensive containment systems. Furthermore, the disclosed systems can operate at reduced noise levels compared to conventional solutions. Furthermore, the disclosed systems can significantly reduce carbon emissions by consuming a portion of the fuel required by current technologies.

[0017] 1 is a block diagram illustrating a system for removing a coating from a substrate consistent with disclosed embodiments. System 100 may include various components depending on the requirements of a particular implementation. In some embodiments, system 100 may include a guidance system 1001, a laser system 116, and a waste removal system 1002.

[0018] These components, namely, guidance system 1001, laser system 116, and waste removal system 1002, are designed to address long-standing needs in the coating removal industry, as previously described. For example, guidance system 1001 features a combination of power supply 103 and induction head 102 that work together to deliver sufficient energy to the coating to burn off some or all of the coating material. The burned-off coating is more easily removed (e.g., compared to loose coating material) compared to conventional coating removal techniques, leaves less residual material on the metal substrate (allowing for a subsequent cleaning process (e.g., laser cleaning, etc.) to remove the residual material more quickly and more efficiently), and waste handling and removal (e.g., by waste extraction system 1002) can be significantly simplified. As described in more detail in the following sections, the disclosed systems can avoid the need for expensive hazardous material containment systems, significantly reduce the amount of hazardous material requiring handling, and avoid expensive hazardous material transportation and disposal methods.

[0019] The induction system 1001 may include various combinations of components configured to deliver sufficient energy to the coating on the metal substrate to incinerate at least a portion of the coating material. For purposes of this disclosure, it should be noted that energy delivery to the coating may refer to the overall process of converting electrical energy from a power source, such as power source 103, into heat sufficient to cause incineration of some or all of the coating material on the metal substrate. In the induction process associated with the induction system 1001, electrical energy from the power source 103 is converted into magnetic energy using the induction head 102. Through induction, this magnetic energy results in the generation of surface eddy currents in the substrate, which can result in rapid heating of the substrate. This thermal energy is transferred to the coating material on the substrate at an energy density level sufficient to cause incineration of some or all of the coating material. References to induction, thermal induction, induction heating, and the like are used interchangeably in this disclosure to refer to processes for heating conductive materials by electromagnetic induction.

[0020] As shown in FIG. 1 , the induction system 1001 may include at least one induction head 102 and a power supply 103 electrically connected to the at least one induction head 102. The power supply 103 may be used to variably select the amount of energy available for delivery to the substrate. For example, a user may select a power output level between 0 and 110 W to deliver alternating current to the induction head 102. If the user knows the thickness of the coating, a predetermined power setting may be used. For example, for a 15 mil coating, a 12.5 kW output may be selected. If the user does not know the thickness of the coating, the power output level may be iteratively selected. For example, starting with a power output of several kW, the user may gradually increase the power output until the energy density reaches a sufficient level to burn off some or all of the coating. Additionally or alternatively, the user may select the power output as a percentage of the induction system's maximum power output, increasing the power output in increments of, for example, 1%, 5%, or 10%.

[0021] The induction head 102 may include various configurations depending on the requirements of a particular application. In the disclosed embodiment, the induction head 102 includes an induction coil. When power is supplied to the induction head 102 (e.g., via electrical energy generated by the power supply 103), an alternating current circulates through the coil of the induction head 102, thereby generating a rapidly changing magnetic field around the coil. When the induction head 102 is activated and positioned in proximity to a metal substrate, the rapidly changing magnetic field induces eddy currents in the metal substrate, which causes the substrate to heat. With sufficient energy transfer from the induction head 102 to the metal substrate, the resulting heat can be used to burn off all or a portion of the coating material present on the substrate.

[0022] More specifically, AC current from a power source is fed to a rectifier voltage regulator. The rectifier voltage regulator maintains a constant DC voltage output. An inverter converts the DC current to a desired AC current having a desired frequency for burning off the coating material. The generated desired AC current passes through an oscillation capacitor and a high-frequency transformer. The high-frequency transformer excites an induction coil located within an induction head. The induction head is placed against the iron or other compatible material of the base substrate. The induction coil generates energy by creating an inductive coupling between the induction coil and the base material of the target coated component.

[0023] The die-hardening induction head of the induction head assembly is held by the induction head hand grip and placed against the exposed surface of the outer coating of the target coated member. The induction between the induction head assembly and the target substrate member material transfers energy to generate heat, thereby burning off the coating material and removing it from the substrate. The induction between the induction head assembly and the target substrate member material generates heat that can at least partially separate and / or burn off the coating from the substrate surface. After a dwell time for the induction coating removal process, the induction head assembly is moved in a direction to expose the intact coating material. The translation distance may be selected to be smaller than the dimensions of the induction head of the induction head assembly. In some cases, the induction head assembly may be moved continuously at a speed slow enough to allow for the desired level of burning off and removal of the coating material from the substrate.

[0024] According to some exemplary embodiments, the coil of the induction head 102 may be flat (e.g., arranged so that the coil elements are aligned on or parallel to the plane of the coil). The coil may be helical in shape. In such embodiments, the magnetic field may be generated perpendicular to the plane of the coil, making this type of coil suitable for transferring energy to flat surfaces. The coil may be cylindrical in shape, thereby generating a magnetic field along the axis of the coil. Such coils may be used for cylindrical or tubular substrates. According to some other embodiments, the coil may include a U-shaped coil. In such embodiments, the magnetic field may be generated between the legs of the coil and move horizontally from one leg to the other. Such coils may be used for localized regions or edges of components. Coils of any other suitable shape may be used to remove coatings from flat surfaces, rounded, contoured surfaces, inside corners, outside corners, both sides of a substrate, rounded rivets, bolts, or any other type of surface.

[0025] In addition to the coil associated with the induction head 102, the shape or envelope associated with the induction head 102 may be configured in any shape suitable for a particular application. In some cases, the induction head 102 includes a rectangular shape, where the length of the head is greater than the width. The induction head 102 may be made from a variety of materials. In some embodiments, the induction head 102 may include copper or aluminum, or other materials with sufficient conductivity to allow efficient energy transfer from the induction head 102 to the substrate. The induction head 102 may include other materials and configurations. For example, in some embodiments, the induction head 102 may include ceramic material(s) or other insulating material with conductive material disposed within or on the surface of the material.

[0026] The surface of the induction head that contacts the coating (referred to as the "contact surface") may be flat or textured. For example, a textured induction head surface may facilitate the removal of coating material from the surface. Once heat is generated by the induction assembly head and at least a portion of the coating is burned or detached from the substrate, moving the textured induction head in a direction that exposes the intact coating material may induce friction between the induction head and the burned and / or detached coating. This friction may then aid in removing the burned and / or detached coating from the substrate. The texture on the contact surface may take a variety of forms. The texture may consist of a regular pattern specifically designed to maximize friction when the induction head assembly moves in a particular direction. Examples include micrometer- or millimeter-scale patterns organized into a periodic lattice. Alternatively, the texture may include randomly arranged micrometer- or millimeter-scale patterns. These patterns may be uniform in size and shape, or may vary randomly in size and shape. The overall size, shape, and placement of these patterns contribute to a desired level of friction between the induction head assembly and the burned and / or separated coating while allowing the displacement of the induction head assembly to remain comfortable.

[0027] According to some exemplary embodiments, the substrate may be preheated prior to utilizing the induction system. Preheating the substrate creates a thermal expansion differential between the substrate and the coating, which weakens the bond between the substrate and the coating, making the coating easier to remove. Preheating the substrate may also reduce the risk of thermal shock within the substrate, which may cause damage to the substrate. The preheating system may be operated, for example, by an infrared heater, a hot plate, a heat gun, or a torch.

[0028] In the disclosed embodiment, the power supply 103 and at least one induction head 102 are configured to deliver energy to the coating at an energy density level above the coating's burn threshold. The energy density delivered by the induction system may depend on the properties of both the coating and the substrate, including the coating thickness. Coating materials may include various types of materials, such as epoxies, urethanes, lead-based paints, flame retardants, organic materials, adhesive rubbers, vulcanized rubbers, and chlorinated rubbers. Often, coatings may also contain harmful ingredients, such as lead-based pigments, chromium-based pigments, or cadmium-based pigments, which are found in some types of paints.

[0029] The disclosed induction system may operate on various types of substrate materials. In some cases, the substrate may include a metallic material (e.g., a ferrous metal). Various parameters of the induction system may be adjusted to achieve an energy density above the burn threshold of the coating material(s). At least some of these parameters include voltage, current, current frequency, induction head-to-substrate distance, contact duration, and induction head movement speed.

[0030] The voltage (V) and current (I) supplied by the power supply determine the energy output (P) of the induction system according to the formula P=V×I. The frequency of the alternating current affects the penetration depth of the magnetic field generated by the induction coil. Lower frequencies penetrate deeper into the substrate, making these frequencies suitable for thicker coatings, while higher frequencies result in shallower heating that is ideal for thin coatings or surface treatments. In some exemplary embodiments, the induction system operates at an output frequency of 10-25 KHz. The distance (d) between the induction head and the substrate determines this relationship.

number

[0031] This influences the strength of the magnetic field (B) applied to the substrate. The closer the induction head is to the substrate, the stronger the magnetic field. Furthermore, the contact duration and movement speed of the induction head control the energy transferred to the substrate, with longer contact resulting in more energy transfer and higher substrate temperature.

[0032] Additionally, the number of coils included in the induction head may be selected to facilitate a desired level of energy transfer to the substrate / coating. For example, increasing the number of coils can increase the strength of the resulting magnetic field generated by the induction head, thereby facilitating increased transfer of electrical energy to the substrate via induction. The coils of the induction head may be arranged concentrically. In some cases, the induction head 102 includes 10 or more coils. In other cases, the induction head 102 may include at least 100 coils or at least 1000 coils.

[0033] The energy density of the induction system may be selected or controlled by the user and may be adjusted until it reaches the burnout threshold of a particular coating. Any of the aforementioned parameters of the induction system may be adjusted, alone or in combination, to reach the burnout of the coating.

[0034] According to some exemplary embodiments, the energy density of the induction system may be adjusted to favor detachment of the coating over incineration of the coating. For indoor applications where fumes may be harmful, the system parameters may be configured to ensure that the coating is detached from the substrate without being incinerated.

[0035] According to some exemplary embodiments, the energy density delivered by the induction system may be preset by a user who knows the nature and thickness of the coating and the nature of the substrate. The contact duration may be controlled by a timing system, while the remaining parameters of the induction system may be known theoretically or empirically for the corresponding coating and substrate.

[0036] The parameters of the induction system may also be automatically selected and adjusted based on data received by the induction system. The induction system may include, for example, a substrate temperature measurement device (e.g., a pyrometer or laser thermometer). The energy density delivered by the induction system may be varied, for example, according to the measured temperature of the substrate (e.g., in a feedback loop), and the induction system may stop delivering energy to the substrate when a substrate temperature corresponding to the coating burn-off threshold is reached. The substrate temperature measurement device may also include a temperature control security system. For example, if the substrate temperature reaches a predetermined threshold, the induction system may shut off and interrupt the thermal induction process. This predetermined threshold may be set, for example, to a fraction of the temperature required to change the material properties or structure of the substrate. In some cases, the threshold temperature may be approximately 800°F for some metals. Other threshold temperature values ​​may be used (e.g., set by a user) depending on the requirements of a particular application. The data received by the induction system may include data generated by laser scanning or machine vision of the surface to be treated.

[0037] The induction system 1001 may also include other components, such as various types of cooling units. In some cases, the induction system 1001 includes a water chiller or air cooler. Such cooling systems may be integrated with the induction system 1001 or may be used separately. A water chiller or other type of cooler may be used to maintain the induction coating removal unit at a suitable operating temperature during the induction coating removal process.

[0038] In some embodiments, the guidance system 1001 may include one or more automated components designed to provide controlled, automated movement of the guidance system relative to the substrate being coated. For example, the guidance system 1001 may include a motor for controlling the movement of the guidance system via one or more drive wheels. Additionally, one or more tracks may be used to enable the guidance system to move along a predetermined path relative to the substrate. For example, the track(s) may be attached to the substrate (e.g., via one or more magnetic mounts), and a motor in the guidance system may cause movement of the guidance system along the track(s) (e.g., via drive wheels, screw drive mechanisms, etc.). Such a system may help provide uniform energy delivery to the substrate / coating (e.g., via precise control of the induction head-to-substrate distance and / or the relative velocity between the induction head and the substrate).

[0039] In automated embodiments, two or more operating parts of the system may be integrated together into a single unit supported by a frame. The frame may be movable on wheels or rollers or may be moved via a screw drive mechanism (or any other suitable drive system). The frame may move along a track to control the direction of movement during surface preparation. The track may be an attached part of the coating removal system. In other cases, the coating removal system may utilize existing infrastructure, such as using I-beam flanges as rails to facilitate movement of the coating removal system. In still other cases, the coating removal system may be mounted on a robotic crawler system designed to navigate coated infrastructure (e.g., bridges, ships, buildings, etc.). In some cases, one or more components of the coating removal system (e.g., a guidance system, a laser ablation system, and / or a waste management system, etc.) may be removably attached to a frame or housing so that any of those components can be removed from the integrated system and used independently (e.g., for detailing and processing of difficult-to-access areas).

[0040] When the temperature of the substrate reaches the incineration threshold of the coating, the induction system may partially or completely incinerate the coating, leaving fumes and incinerated waste near the substrate. A waste removal system 1002 handles the exhaust of at least a portion of the coating, including incineration products generated by the delivery of energy to the coating. In some embodiments, data received by the induction system to control system automation may also include waste detection (particulate flow, presence of carbon, etc.) in the waste removal system 1002.

[0041] The waste removal system 1002 may include various components and configurations to facilitate removal of incineration products generated by inductive heating of the substrate / coating. In some exemplary embodiments, the waste removal system 1002 may include at least one vacuum system 110. The waste removal system 1002 may include a scraper blade 114 associated with the at least one vacuum system, the scraper blade 114 configured to remove at least a portion of the incineration products generated by delivering energy to the coating. As previously described, operation of the vacuum system 110 may be automated based on various observed conditions, such as a temperature threshold associated with the substrate or coating, detection of one or more changes associated with the coating as a result of combustion (e.g., color change, blistering, etc.), detection of incineration products (e.g., airborne particulates, fumes, smoke, etc.), among other sensed conditions.

[0042] The waste removal system 1002 may also include one or more filter components. For example, in some cases, the waste removal system 1002 may include a filter unit that includes a carbon filter and / or a HEPA filter.

[0043] In some cases, waste removal system 1002 may include only a single vacuum system 110. In such cases, vacuum system 110 may be used to remove incineration products produced by operation of guidance system 1001 and may be used to remove ablation products produced by operation of laser system 116 (described further below). In other cases, waste removal system 1002 may include separate vacuum systems 110 for each of guidance system 1001 and laser system 116.

[0044] The combined effect of the guidance system 1001 and waste removal system 1002 most often results in a surface that is well prepared for the laser system 116. In some cases, processing of the coating with the guidance system 1001 and waste removal system 1002 provides a clean substrate surface that is free of even a residual coating layer. In such cases, subsequent processing of the substrate surface using the laser system 116 can help remove any small amounts of coating residue (e.g., a coating layer not readily observable with the naked eye) to result in a bare substrate. In other cases, processing with the guidance system 1001 may leave a thin layer of residual coating that is removed using the laser system 116.

[0045] The residual layer of coating may be defined as the portion of the coating that is not removed after use of the induction system, the vacuum system 110, or optionally the scraper blade 114, where the induction system includes at least one induction head 102 and a power source electrically connected to the at least one induction head. In such an embodiment, the laser system 116 may be configured to pyrolytically ablate or burn the residual layer of coating on the substrate. The residual layer of coating may include at least one of an organic coating, surface rust, hydrocarbon residue, or contaminants from the original coating.

[0046] The laser system 116 may include at least one of a pulsed laser, a roller-backed pulsed laser, or a continuous wave laser. In some embodiments, the power of the pulsed laser may be set at any suitable value between 300 W and 2 kW. In other embodiments, the power of the continuous laser may be set at any suitable value between 100 W and 2 kW. The pulsed laser may include, for example, a CO2-TEA laser or a Nd:YAG laser. In some cases, the pulsed laser uses a high-power (500 W) pulsed Nd:YAG laser (1064 nm wavelength) to remove contaminants from base metals, including organic coatings, surface rust, hydrocarbon residues, and low-level solid radiation contamination. In yet another aspect, the pulsed laser process uses a high-power (600 W) pulsed Nd:YAG laser (1064 nm wavelength), a high-power (2 kW) pulsed Nd:YAG laser (1064 nm wavelength), or a medium-power (300 W) pulsed Nd:YAG laser (1064 nm wavelength).

[0047] In some embodiments, the nature of the laser (pulsed or continuous), the power of the laser, the frequency of the laser, the pulse duration, the pulse frequency, and the duration of exposure of the coating to the laser may be selected depending on at least one of the nature of the coating, the thickness of the coating, the nature of the substrate, or eye safety regulations. For example, a lower pulse frequency may be used to remove a thicker layer of the coating, and a higher pulse frequency may be used to remove a thinner layer of the coating. In some cases, a continuous wave laser ablation system may provide variable output power capabilities, for example, from 200 W to 2 kW.

[0048] For example, for organic coatings, a UV or visible laser with a low power setting and short pulse duration (in the nanosecond to picosecond range) may be selected. For organic coatings or surface rust, an infrared laser with a higher power setting and longer pulse duration in the nanosecond to millisecond range may be selected, with the power level associated with the surface rust residual layer being lower than the power level associated with the organic coating residual layer.

[0049] Various types of laser emitters may be used in laser ablation systems. In some cases, a roller-supported pulsed laser emitter may emit multiple laser beams simultaneously. One or more of the emitted laser beams may be scanned relative to a work surface containing residual coating material. In some cases, the scanning laser beam(s) may be arranged in a linear, evenly spaced array. The laser(s) may be scanned using various scanning patterns, such as a linear pattern, a circular pattern, a rectangular pattern, or any other desired pattern. The roller-supported pulsed laser emitter may include two or more pulsed laser support wheels for supporting the roller-supported pulsed laser emitter at a fixed distance from the surface of the substrate.

[0050] During operation, the pulsed laser emitter emits a scanning pulsed laser beam that is directed toward and focused on the target surface. The pulsed laser emission beam generates a plasma that ablates or pyrolytically burns any residual material remaining after the induction process, thereby converting the residual material into vaporized residue. The vaporized residue is collected by a vaporized residue collection vacuum created by a fume extractor. The fume extractor can be incorporated into the pulsed laser emitter / laser ablation system, or the fume extractor can be provided as a separate device. The power of the pulsed laser emission beam and the distance between the laser emitter and the workpiece surface can be adjusted based on the composition of the residual material and / or the thickness of the residual material remaining on the substrate surface.

[0051] Vaporized residue from the ablated coated component base layer is collected using a fume extractor. The fume extractor may be separate from the pulsed laser, or the fume extractor may be integrated into the pulsed laser system. The ablation process in combination with a fume extractor (waste management system) may eliminate the need for the use and installation of expensive material containment equipment.

[0052] The process continues with an optional decision step to determine whether there is any heavy corrosion (such as layered rust) remaining after the laser ablation that needs to be removed. If there is corrosion not removed by the laser, such as layered rust, that needs to be removed, the process can use a needle scaler or power chisel to remove such corrosion from the substrate surface. Other corrosion removal techniques may include the use of manual or powered wire brushes or other mechanical means. The laser ablation process may be repeated until the desired level of surface cleanliness is achieved. Once the substrate is cleaned, it may be inspected to identify whether repair is required. If necessary, repairs are completed using an appropriate repair process, such as welding, brazing, metal stitching, hammering, or any other suitable metal repair process. Once the substrate is deemed structurally sound, any finishing work is completed. Finishing may include machining, grinding, sanding, polishing, etc. If a final clean is required before applying a new coating, the surface can be further prepped. Once the surface is properly prepped according to the project specifications, a new basecoat can be applied to the prepped bare target substrate member surface. An outer coating or protective coating may be applied to the new base coat.

[0053] Power to the coating removal system may be provided via a fixed power grid or a portable power source, such as a generator. Primary equipment, including the induction coating removal unit and pulsed laser ablation system, may be powered directly from the generator or via an optional power distribution panel. Similarly, support equipment, such as water chillers and fume extractors, may be powered directly from the generator or via an optional power distribution panel.

[0054] In some cases, the disclosed waste extraction system may include a vacuum nozzle attached to the pulsed laser end effector to extract ablation material from the workpiece and transport it by vacuum through a fume extractor with multi-stage filtration. The vacuum nozzle may be fabricated and adapted to the size and / or shape of the induction head, for example. An example of a vacuum nozzle can be seen in FIGS. 4A-4B, where a vacuum nozzle 110 is attached to induction head 102. The vacuum nozzle may be designed, for example, with computer-aided design (CAD) software and manufactured with a 3D printer or a computer numerical control (CNC) machine. The configurable nature of the vacuum nozzle allows for adaptation to virtually any induction head or laser system. The distance between the nozzle and the substrate may be adapted to the nature of the coating, the shape of the substrate, or the type of vacuum system. Additionally, the material used for the vacuum nozzle may be selected to withstand, for example, the high temperatures surrounding the induction head or the environmental conditions in which the system is used. The filter unit may include one or more self-cleaning particle filters, activated carbon filters, and / or high-efficiency HEPA filters to collect particles and gases resulting from the laser ablation process.

[0055] In some embodiments, the coating removal process can be fully automated, incorporating all operating components of the guidance system 1001, laser system 116, and waste removal system 1002 into a single unit. This automated system can autonomously move from one zone of the substrate to another once a predetermined portion of the coating has been removed. Movement can be facilitated by wheels, rollers, tracks, or magnetically attached robotic crawlers.

[0056] In some embodiments, the assessment of whether the predetermined portion of the coating has been removed can be performed using at least one of image analysis, surface profilometry, colorimetry, reflectance measurement, adhesion testing, or visual inspection with a camera combined with thickness measurement. The predetermined portion of the coating to be removed before the system moves to a new zone can be adjusted based on the properties of the surface. For example, the predetermined portion of the coating to be removed may be set to 100% for a flat surface, but less than 100% for a non-flat surface.

[0057] In some embodiments, the operating parts of the system may be used independently and detached for areas where not all coating has been removed or where an automated unit cannot fit or move. It should be understood that different components of the system may be used in a variety of different configurations without departing from the scope of the disclosed embodiments. In some embodiments, all components of the system may be used independently. In other embodiments, various combinations of at least two components of the system may be used.

[0058] 2A-2D include schematic diagrams of example coating removal systems consistent with certain embodiments of the present disclosure. Referring to FIG. 2A, a schematic diagram of an example coating removal system 200 consistent with certain embodiments of the present disclosure is provided. The coating removal system 200 may include an induction system and a vacuum system 110. According to some embodiments, the induction system may include an induction head 102 and a power source (not shown in FIG. 2A ), where the power source and induction head 102 are configured to deliver energy to the coating 106 via the magnetic field 104 at an energy density level above the combustion threshold of the coating. Additionally, the vacuum system 110 may be configured to extract at least a portion of the coating 106, including combustion products generated by the delivery of energy to the coating 106.

[0059] 2A, the vacuum system 110 and the induction head 102 may be used separately as two different systems, with the vacuum system 110 following the induction head 104. However, in some exemplary embodiments, the vacuum system 110 may be incorporated into the induction head 102 (e.g., within a common housing).

[0060] FIG. 2B illustrates another example of a coating removal system 300 consistent with some embodiments of the present disclosure. The coating removal system 300 may include an induction system, a vacuum system 110, and a scraper blade 114 associated with the vacuum system 110. According to some embodiments, the induction system may include an induction head 102 and a power source (not shown in FIG. 2B ), where the power source and induction head 102 are configured to deliver energy 104 to the coating 106 at an energy density level above the combustion threshold of the coating. The scraper blade 114 may be configured to remove at least a portion of the incineration products generated by the delivery of energy to the coating, and the vacuum system 110 may be configured to extract at least a portion of the coating, including the incineration products generated by the delivery of energy to the coating 106. For example, if the energy delivered to the coating is insufficient to incinerate the entire coating 106, a portion of the coating 106 may still be partially attached to the substrate 108. In such cases, the scraper blade 114 may help remove the portion of the coating that has not been incinerated and guide it toward the vacuum system 110. In some cases, the scraper blade 114 may also help remove incineration products that remain attached to the substrate. Additionally, the scraper blade 114 may help guide the incineration waste products toward the vacuum system 110.

[0061] While a scraper blade is shown, it should be noted that other components may be included or used in combination with or in place of the disclosed scraper blade. For example, in some cases, the disclosed systems may include (or be used with) a needle gun, needle scaler, or power chisel. Such tools use pressurized air or electrical power to propel a chisel or bit back and forth. The chisel or bit is rapidly moved across the surface to remove layered or packed rust, scale, and debris such as concrete splatter, dirt, or other bulk residue from the workpiece as needed, before or after an induction or laser ablation process.

[0062] In particular, compared to conventional coating removal systems (e.g., media blast systems), the disclosed systems can provide clean, smooth finishes after induction and laser ablation processes. For example, in some cases, the disclosed systems can produce finishes on substrates or base materials with surface profiles that vary less than 25 nanometers (<5 microns). This compares to surface profiles that vary less than +65 / -55 nanometers (>12 microns) from grit blast coating removal processes.

[0063] 2B, the vacuum system 110 with attached scraper blade 114 may be used separately from the guide system 102 (e.g., as two independent systems). In such an embodiment, the vacuum system 110 may follow the guide system 102. However, in other cases, the vacuum system 110 (and optional scraper blade 114) may be incorporated with the guide system 102 to provide an integrated system.

[0064] Referring to FIG. 2C , a schematic diagram of another example coating removal system 400 consistent with some embodiments of the present disclosure is shown. The coating removal system 400 may include a guidance system, a first vacuum system 110, a laser system 116, and a second vacuum system 120. The guidance system and vacuum system 110 may be configured as previously described (e.g., in FIGS. 2A and 2B ), and the laser system 116 may be configured to thermally ablate or burn the substrate residual layer 118. As previously described, the residual layer of the coating 118 is defined as the portion of the coating 106 that was not removed after use of at least one of the guidance system or the waste removal system. According to some exemplary embodiments, the residual layer of the coating 118 may include at least one of an organic coating, surface rust, hydrocarbon residue, or contaminants from the original coating layer, among other residual materials. Additionally, the vacuum system 120 may be configured to extract products produced by the ablation or thermal decomposition of the residual layer of the coating. 2C, the induction system delivers energy to the coating 106 to burn off at least a portion of the coating. The burned off waste material is exhausted by the vacuum system 110, thereby leaving a residual layer of the coating 118 on the substrate 108. The laser system 116 follows, ablating the residual layer 118 and creating ablation waste material 122 (e.g., fumes, particulates, etc.), which is exhausted by the vacuum system 120.

[0065] 2C, the vacuum system 110 may be integrated into the guidance system 102, and the vacuum system may be integrated into the laser system 116. In some other embodiments, the vacuum systems 110 and 120 may be used separately from the guidance system 102 and the laser system 116. According to some exemplary embodiments, the first vacuum extraction and the second vacuum extraction are performed by the same fume extraction unit.

[0066] In yet some other embodiments, the guidance system, laser system 116, and vacuum systems 110 and 120 may all be incorporated into a fully integrated system. In some other embodiments, at least one system may be used separately from the others.

[0067] The system disclosed in Figure 2C may be further modified to include a scraper blade 114, as shown in Figure 2D. In such an embodiment, the elements of the system may be configured as described above. In some cases, the elements of the system may be incorporated into one another to form an integrated system, or at least one element of the system of Figure 2D may be used as a separate component / system.

[0068] The figure provides a flowchart depicting an exemplary method for removing a coating from a substrate. In step 502, the method 500 may include selecting an output frequency of the induction system between 20 kHz and 50 kHz depending on the coating, the coating including at least one of an epoxy, a urethane, a lead-based coating, a flame-retardant coating, an organic coating, an adhesive rubber, a vulcanized rubber, or a chlorinated rubber.

[0069] In step 504, the method 500 may include using an induction system configured to deliver energy to the coating at an energy density level at or above the burn-off threshold of the coating.

[0070] In step 506, method 500 may include determining whether incineration products generated by the delivery of energy to the coating need to be removed from the substrate. If the incineration products need to be removed, in step 508, method 500 may include using a scraper blade associated with a vacuum system, the scraper blade configured to remove at least a portion of the incineration products generated by the delivery of energy to the coating. If the incineration products do not need to be removed, or if the incineration products need to be removed and step 508 has already been performed, in step 510, method 500 may include performing a vacuum stage to extract at least a portion of the coating, including the incineration products generated by the delivery of energy to the coating.

[0071] In step 512, the method 500 may include using a laser system configured to pyrolytically ablate or burn the substrate residual layer of the coating.

[0072] As previously mentioned, the nature of the laser (pulsed or continuous), the power of the laser, the frequency of the laser, the pulse duration, the pulse frequency, and the duration of exposure of the coating to the laser may be selected depending on at least one of the nature of the coating, the thickness of the coating, the nature of the substrate, or eye safety regulations.

[0073] In step 514, the method 500 may include performing a vacuum stage to extract products produced by the ablation or pyrolysis of the residual layer of the coating. In some embodiments, the first vacuum stage and the second vacuum stage are performed by the same fume extraction unit.

[0074] The foregoing description is presented for purposes of illustration. These descriptions are not exhaustive and are not limited to the precise forms or embodiments disclosed. Modifications and adaptations of the embodiments will be apparent from consideration of the specification and practice of the disclosed embodiments. While certain components have been described as being combined with each other, such components may also be integrated with each other or distributed in any suitable manner.

[0075] Furthermore, although exemplary embodiments have been described herein, the scope includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., combinations of aspects across various embodiments), adaptations, or variations based on this disclosure. Claim elements should be interpreted broadly based on the language used in the claims and not limited to the examples described herein or during prosecution of the application; those examples should be interpreted as non-exclusive. Furthermore, the steps of the disclosed methods may be modified in any manner, including rearranging steps or inserting or deleting steps.

Claims

1. 1. An induction system for removing a coating from a substrate, comprising: at least one induction head; a power supply electrically connected to the at least one induction head, the power supply and the at least one induction head configured to deliver energy to the coating at an energy density level that is equal to or greater than a burn-off threshold for the coating; a vacuum system configured to extract at least a portion of the coating including incineration products produced by the delivery of energy to the coating; A guidance system comprising:

2. and a scraper blade associated with the vacuum system, the scraper blade configured to remove at least a portion of the incineration products generated by delivering the energy to the coating. The system of claim 1 .

3. The system of claim 1 , wherein the induction head has a width that is less than its length.

4. The system of claim 1 , wherein the substrate comprises a metallic material.

5. The system of claim 1 , wherein the substrate comprises an iron-based metal.

6. The system of claim 1 , wherein the coating comprises at least one of an epoxy, a urethane, a lead-based coating, a flame-retardant coating, an organic coating, an adhesive rubber, a vulcanized rubber, or a chlorinated rubber.

7. The system of claim 1 , wherein the coating comprises at least one of a lead-based pigment, a chromium-based pigment, or a cadmium-based pigment.

8. 10. The system of claim 1, wherein the output frequency is between 20 kHz and 50 kHz.

9. The system of claim 1 , wherein the induction process uses an alternating current and an induction coil.

10. 1. A system for removing a coating from a substrate, comprising: at least one induction head; a power supply electrically connected to the at least one induction head, the power supply and the at least one induction head configured to deliver energy to the coating at an energy density level that is equal to or greater than a burn-off threshold for the coating; a vacuum system configured to extract at least a portion of the coating including incineration products produced by the delivery of energy to the coating; a laser system configured to pyrolytically ablate or burn the substrate residual layer; a vacuum system configured to extract products produced by ablation or pyrolysis of the residual layer of the coating; A system comprising:

11. The system of claim 10 , wherein the laser system comprises at least one of a pulsed laser, a roller-backed pulsed laser, or a continuous wave laser.

12. 11. The system of claim 10, further comprising a scraper blade associated with the vacuum system, the scraper blade configured to remove at least a portion of the incineration products generated by delivering the energy to the coating.

13. The system of claim 10 , wherein the induction head has a width that is less than its length.

14. The system of claim 10 , wherein the substrate comprises a metallic material.

15. The system of claim 10 , wherein the substrate comprises an iron-based metal.

16. The system of claim 10 , wherein the coating comprises at least one of an epoxy, a urethane, a lead-based coating, a flame-retardant coating, an organic coating, an adhesive rubber, a vulcanized rubber, and a chlorinated rubber.

17. The system of claim 10 , wherein the coating comprises at least one of a lead-based pigment, a chromium-based pigment, or a cadmium-based pigment.

18. The system of claim 10, wherein the output frequency of the induction system is between 20 kHz and 50 kHz.

19. The system of claim 10 , wherein the induction system uses an alternating current and an induction coil.

20. The system of claim 10 , wherein the residual layer of coating comprises at least one of an organic coating, surface rust, hydrocarbon residue, or contaminants from a base layer.

21. The system of claim 10 , wherein the first vacuum extraction and the second vacuum extraction are performed by the same fume extraction unit.

22. 1. A method for removing a coated substrate, comprising: using an induction system configured to deliver energy to the coating at an energy density level at or above a burn-off threshold of the coating; performing a vacuum step to extract at least a portion of the coating, including combustion products produced by the delivery of energy to the coating; using a laser system configured to pyrolytically ablate or burn the substrate residual layer of the coating; performing a vacuum step to extract products produced by ablation or pyrolysis of the residual layer of the coating; Includes.

23. 23. The method of claim 22, further comprising selecting an output frequency of the induction system between 20 kHz and 50 kHz in response to the coating, wherein the coating comprises at least one of an epoxy, a urethane, a lead-based coating, a flame-retardant coating, an organic coating, an adhesive rubber, a vulcanized rubber, or a chlorinated rubber.

24. 23. The method of claim 22, further comprising using a scraper blade associated with the vacuum system, the scraper blade configured to remove at least a portion of the incineration products produced by delivering the energy to the coating.

25. 23. The method of claim 22, wherein the first vacuum stage and the second vacuum stage are performed by the same fume extraction unit.

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