Abstract:
An electropolishing or electroplating system and method for metal conveyor belts is described. As opposed to conventional polishing processes in which the product is guided around rollers which direct the product into and out of an electrolyte bath, embodiments of the present invention pass the product through a housing supplied with a continuous directional flow of electrolyte. Thus, the electroplating or electropolishing can be targeted to specific areas of the product, such as the edges and/or the center of a conveyor belt, and straight products can pass through the housing without deformation.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    Embodiments of the claimed invention relate to electropolishing and electroplating, and in particular, systems and methods for electropolishing or electroplating localized areas of continuous assemblies of interconnected components, such as conveyor belts. 
         [0003]    2. Description of Related Art 
         [0004]    Conveyor belt systems are used in various industrial fields for material handling and processing purposes. For instance, conveyor systems are used within food processing systems in which food items are placed on the support surface of a conveyor belt and processed, while being conveyed from one location to another. Various types of conveyor belts exist, including modular conveyor belts, which are especially popular in food processing systems. Moreover, conveyor systems are often used in a helical accumulator such as that disclose in U.S. Pat. No. 5,070,999 to Layne et al. which allows storage of a large number of items in the conveyor system. 
         [0005]    In the food processing industry, it is of the utmost importance that conveyors belts are sanitary. To accomplish this, conveyor belts are conventionally wiped down, washed, and/or steamed on a regular basis. However, conveyor belts are often very long, extending hundreds or even thousands of feet. In these cases, the belts can be difficult to clean and may become less durable over time due to the thorough process needed to maintain their sanitation. 
         [0006]    Electropolishing and electroplating has been previously used in a number of applications. U.S. Pat. No. 4,895,633 to Seto et al. discloses a conventional molten salt electroplating apparatus for forming plating on steel strips, sheets, and wires. A steel strip is continuously unwound from a pay-off reel, passed through a looper, and sent to a pretreatment apparatus. Next, the surface of the steel strip is plated as it passes between electrodes immersed in electroplating solution. The steel strip is then washed and dried, passed through a looper and a shearing machine, then wound onto a tension reel. 
         [0007]    U.S. Pat. No. 7,407,051 B1 to Farris et al. discloses a stainless steel sprocket support shaft for a nozzleless conveyor belt and sprocket cleaning apparatus. The stainless steel sprocket may be surface finished by electropolishing. U.S. Pat. No. 5,491,036 to Carey, II et al. generally discloses an electrolysis process for applying a tin coating of carbon steel. 
       SUMMARY OF THE INVENTION 
       [0008]    The above described patents propose a variety of methods for electropolishing or electroplating various materials. However, there still exists a need for a system and method for electropolishing and electroplating metal conveyor belts that improves sanitation and product release characteristics, particularly with respect to conveyor belts used in food processing. There also exists a need for a system and method for electropolishing and electroplating metal conveyor belts that reduces wear and friction on the conveyor belts. There further exists a need for a system and method for electropolishing and electroplating localized areas of metal conveyor belts. 
         [0009]    In view of the foregoing, one aspect of the present invention provides a continuous electropolishing and/or electroplating process for localized areas of metal conveyor belts. This process provides benefits such as improved sanitation, improved product release characteristics, brighter cosmetic appearance, removal of weld discoloration, and reduced wear and friction, which are particularly important for conveyor belts used in food processing. 
         [0010]    As opposed to conventional polishing processes in which the product is guided around rollers which direct the product into and out of an electrolyte bath, embodiments of the present invention pass the product through a housing supplied with a continuous directional flow of electrolyte. Thus, the electroplating or electropolishing can be targeted to specific areas of the product, such as the edges of a conveyor belt, and straight products can pass through the housing without deformation (i.e., because guiding by rollers into and out of a bath is not required). This reduces the amount of electrolyte required in the system; reduces human exposure to the electrolyte during operation; reduces evaporation and environmental contamination of the electrolyte; reduces set-up time because the electrolyte can be quickly removed from the polishing area; and optimizes current and fluid flow to improve efficiency compared to conventional processes. In addition, fresh electrolyte can be concentrated at the polishing site, without solution in a bath of used electrolyte, for more effective electropolishing or electroplating. 
         [0011]    Belts can be separated into smaller sections, typically 50 to 100 feet long, for ease of handling and shipping. These sections may be connected sequentially, such that the leading end of a new roll of belt is connected to the trailing end of the previous roll of belt, to maintain a continuous process. These sections can be disconnected and placed on separate take-up rolls after processing. Leader chains may also be used to guide the ends of the belt into and out of the bath while maintaining tension. Materials used in the process, such as the plate material and electrolyte material, may be of any suitable type such as are currently used or may be developed for electropolishing and electroplating. 
         [0012]    According to one embodiment, a system for electropolishing or electroplating a conveyor belt is described. The system comprises a housing comprising an electrical conductor and an opening configured to receive a portion of the conveyor belt in the opening; a seal provided in the opening; an inlet configured to supply electrolytic solution to the housing; and an electrical contact configured to apply current to the conveyor belt. 
         [0013]    According to another embodiment, a method for electropolishing or electroplating a conveyor belt is described. The method comprises guiding a portion of the conveyor belt through a housing comprising an electrical conductor and a seal; applying current to the conveyor belt with an electrical contact; and supplying an electrolytic solution to the housing through an inlet, thereby electroplating or electropolishing the portion of the conveyor belt. 
         [0014]    Still other aspects, features and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention also is capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only. 
           [0016]      FIG. 1  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with an embodiment. 
           [0017]      FIG. 2  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with an embodiment. 
           [0018]      FIG. 3  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    A system and method for electropolishing or electroplating a continuous assembly of interconnected components is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. It is apparent to one skilled in the art, however, that the present invention can be practiced without these specific details or with an equivalent arrangement. 
         [0020]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with an embodiment. In this embodiment, the continuous assembly of interconnected components is a conveyor belt  105 . As illustrated in  FIG. 1 , two housings  115 A and  115 B are positioned at the edges of conveyor belt  105  in order to electropolish or electroplate edge links  120 A and edge links  120 B, respectively. In some embodiments, however, only a single housing  115 A or  115 B can be positioned on an edge of conveyor belt  105  to electropolish or electroplate only one of edge links  120 A or edge links  120 B, respectively. It is understood that housing  115 B is cutaway in  FIG. 1  for purposes of explanation only, and that in practice, the exterior of housing  115 B resembles housing  115 A. Further, it is understood that the interior of housing  115 A resembles that shown with respect to housing  115 B. Although not shown in  FIG. 1 , it is contemplated that other features of the conveyor belt may be electropolished or electroplated with or instead of edge links  120 A and edge links  120 B, such as edge guards or lane dividers. 
         [0021]    Electrical contacts  110 A and  110 B placed on conveyor belt  105  cause the conveyor belt  105  to become an anode (in the case of electropolishing) or cathode (in the case of electroplating). Force may be placed on electrical contact  110 A and/or electrical contact  110 B to ensure consistent contact with conveyor belt  105  and consistent current. Such a force can be applied by a spring, a pneumatic system, a hydraulic system, gravity, and/or similar means. In one embodiment, electrical contact  110 A and/or electrical contact  110 B are movable or floating to accommodate variations in the dimensions of conveyor belt  105 . 
         [0022]    In this embodiment, an electrical conductor  125 B is placed in housing  115 B to serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating). In a similar fashion, an electrical conductor (not shown) is placed in housing  115 A to serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating). In this embodiment, electrical conductor  115 B is placed proximate to the edge of edge links  120 B in order to target polishing or plating at the weld  135 B of conveyor belt  105 . However, it is contemplated that electrical conductor  115 B can be placed in any position proximate to any particular area to be electropolished or electroplated. 
         [0023]    In one embodiment, housing  115 A and housing  115 B are made of copper or another conductive material, and can themselves serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating), with or without electrical conductors internal to housing  115 A or housing  115 B. Housing  115 A, housing  115 B and the electrical conductors (i.e., the electrical conductor internal to housing  115 A and electrical conductor  125 B) can be sized and positioned such that the surface of the electrical conductors are equidistant from all surfaces of edge links  120 A and edge links  120 B for even polishing. Nonconductive wear surfaces may be placed in housing  115 A and housing  115 B in any practical configuration, such as a bushing or perforated liner, to prevent contact between conveyor belt  105  and the electrical conductors, to prevent contact between conveyor belt  105  and the electrical conductors while allowing current to flow between the electrical conductors and conveyor belt  105 . 
         [0024]    Although shown as rectangular and elongated in shape, it is contemplated that housing  115 A and housing  115 B can be of any shape or size suitable to achieve electropolishing or electroplating as described herein. Further, housing  115 A and housing  115 B can be constructed as a single body, or can be made of separable components, such as a body and removable lid. 
         [0025]    Electrolyte may be introduced at any point along the length of housings  115 A and  115 B. In this embodiment, electrolyte is introduced into housing  115 A via inlet  130 A. It is understood that electrolyte is introduced into housing  115 B via a similar inlet (not shown). Electrolyte may flow in either direction through housings  115 A and  115 B, i.e., in the direction of travel of conveyor belt  105  through housings  115 A and  115 B, or counter to the direction of travel of conveyor belt  105  through housings  115 A and  115 B. 
         [0026]    In one embodiment, housings  115 A and  115 B are open at the ends to allow electrolyte to flow out and to allow conveyor belt  105  to pass through. In another embodiment, a separate orifice is provided for the electrolyte outflow. The outflow orifice may be arranged in an upward direction to facilitate removal of gases produced during the electropolishing or electroplating process. Orifices are sized to restrict outflow, and housings  115 A and  115 B are provided with seals  140 A and  140 B, respectively, so that the housings  115 A and  115 B are flooded to a level that provides effective electropolishing or electroplating. Seals  140 A and  140 B need not stop liquid flow altogether, but rather restrict it enough to cause flooding of the housing. Exemplary seals can be made of rubber sheeting or brushes. 
         [0027]      FIG. 2  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with another embodiment. In this embodiment, the continuous assembly of interconnected components is a conveyor belt  205  having a plurality of center links  220  to be electropolished or electroplated. Center links  220  are any links positioned between the edges of conveyor belt  205 , and do not necessarily need to be centered between the edges of conveyor belt  205 . Center links  220  are positioned laterally to create a desired turn radius and to control expansion and collapse of the edge links of conveyor belt  205 . A single housing  215  is positioned along the width of the conveyor belt  205  in order to electropolish or electroplate center links  220 . It is understood that housing  215  is cutaway in  FIG. 2  for purposes of explanation only, and that housing  215  is rectangular in shape in use. Although not shown in  FIG. 2 , it is contemplated that other features of the conveyor belt may be electropolished or electroplated with or instead of center links  220 , such as edge guards or lane dividers. Further, although shown and described with respect to a single housing  215  and a single column of center links  220 , it is contemplated that multiple columns of center links  220  may be present, or multiple other features to be electropolished or electroplated, as well as their accompanying housings. 
         [0028]    Electrical contacts  210 A and  210 B are placed on conveyor belt  205  in a manner similar to that described with respect to electrical contacts  110 A and  110 B of  FIG. 1 . An electrical conductor  225  is placed in housing  215  to serve as a cathode (in the case of electropolishing) or an anode (in the case of electroplating). In this embodiment, electrical conductor  225  is placed on the bottom of housing  215 , underneath both of the welded edges  235 A and  235 B of center links  220 . However, it is contemplated that electrical conductor  225  can be placed in any position proximate to any particular area to be electropolished or electroplated. 
         [0029]    As with respect to  FIG. 1 , housing  215  can be made of copper or another conductive material, and can itself serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating), with or without electrical conductors internal to housing  215 . Housing  215  and electrical conductor  225  can be sized and positioned such that the surface of the electrical conductor  225  is equidistant from all surfaces of center links  220  for even polishing. Nonconductive wear surfaces may be placed in housing  225  in any practical configuration, such as a bushing or perforated liner, to prevent contact between conveyor belt  205  and the electrical conductors, to prevent contact between conveyor belt  205  and the electrical conductors while allowing current to flow between the electrical conductors and conveyor belt  205 . 
         [0030]    Although shown as rectangular and elongated in shape, it is contemplated that housing  215  can be of any shape or size suitable to achieve electropolishing or electroplating as described herein. Further, housing  215  can be constructed as a single body, or can be made of separable components, such as a body and removable lid. 
         [0031]    Electrolyte is introduced via inlet  230  at a central location with respect to the length and width of housing  215 , as is described with respect to  FIG. 1 . Electrolyte may flow in either direction through housing  215 , i.e., in the direction of travel of conveyor belt  205  through housing  215 , or counter to the direction of travel of conveyor belt  205  through housing  215 . 
         [0032]    In this embodiment, housing  215  is open at the ends to allow electrolyte to flow out and to allow conveyor belt  205  to pass through. As is described above with respect to  FIG. 1 , a separate orifice may instead be provided for the electrolyte outflow. Housing  215  is provided with a seal  240  so that the housing  215  is flooded to a level that provides effective electropolishing or electroplating, while minimizing electrolyte loss. In this embodiment, seal  240  is positioned on both sides of center links  220 . Although shown and described as separate embodiments, it is contemplated that both the edge links and the center links of a conveyor belt can be polished simultaneously, by combining the embodiment of  FIG. 1  with that of  FIG. 2 . 
         [0033]      FIG. 3  is a perspective view of a system for electropolishing or electroplating a continuous assembly of interconnected components in accordance with an embodiment. In this embodiment, the continuous assembly of interconnected components is conveyor belt  305 . To create a continuous electropolishing or electroplating process, conveyor belt  305  is unrolled from an in-feed roll  340  into cleaning station  345 , traveling in a direction A. Cleaning station  345  cleans the edge links of conveyor belt  305  and degreases them, for example. Conveyor belt  305  is then rinsed at rinse station  350 . 
         [0034]    Electroplating or electropolishing is achieved at electroplating/electropolishing stations  355 . Although illustrated with two electroplating/electropolishing stations  355 , it is contemplated that only a single electroplating/electropolishing station  355  can be provided, or multiple electroplating/electropolishing stations  355  can be provided in series. Electroplating/electropolishing stations  355  have housings  315 A to polish one edge of the conveyor belt, as well as housings opposite to housing  315 A (not shown) to polish the opposite edge of conveyor belt  355 . It is contemplated that housings  315 A, as well as the opposing housings, may be similar or identical to housings  115 A and  115 B, respectively, of  FIG. 1 . Further, although shown and described herein only with respect to housings  315 A, it is contemplated that a similar or identical process may be carried out with respect to the opposing housings. Although not shown in  FIG. 3 , it is contemplated that other features of the conveyor belt may be electropolished or electroplated with or instead of the edge links of conveyor belt  305 , such as edge guards or lane dividers. 
         [0035]    Electrical contacts placed on conveyor belt  305  cause the conveyor belt to become an anode (in the case of electropolishing) or cathode (in the case of electroplating). Electrical conductors are placed in housings  315 A to serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating). Electrolytic solution is provided via inlets  330 A to housings  315 A, immersing the edges of conveyor belt  305  within the housings  315 A in electrolytic solution. 
         [0036]    With respect to electroplating, a current is applied to the electrical conductors, oxidizing the metal atoms that comprise the electrical conductors and allowing them to dissolve into the electrolytic solution. The dissolved metal ions are moved by the electric field to conveyor belt  305 , coating conveyor belt  305  and depositing a layer of metallic material on the surface of conveyor belt  305 . 
         [0037]    With respect to electropolishing, a current is applied to conveyor belt  305 , oxidizing the metal atoms on the surface of conveyor belt  305  and allowing them to dissolve into the electrolytic solution. The dissolved metal ions in the electrolytic solution are moved by the electric field to the electrical conductors. Thus, a smoother, polished surface results on conveyor belt  305 . 
         [0038]    Once conveyor belt  305  has been electropolished or electroplated, it is moved into post-treatment station  360  (where it undergoes, e.g., a nitric acid rinse), then undergoes a final rinse at rinse station  365 . Optionally, conveyor belt  305  can be moved through a dryer (not shown). Conveyor belt  305  is moved onto take-up roll  370 . It is contemplated that conveyor belt  305  can be moved from in-feed roll  340  to take-up roll  370  by any suitable means, such as, for example, a system drive or motor. Although shown and described with respect to the electropolishing or electroplating of the edge links, it is contemplated that  FIG. 3  can be modified to instead or additionally electropolish or electroplate center links, if present. 
         [0039]    Although described herein with respect to conveyor belts, it is contemplated that the methods and systems described herein can be applied to any rollable and/or conductive materials, including chains or other continuous assemblies of interconnected components. Such electropolishing or electroplating applied in accordance with the described embodiments results in improved sanitation, reduced wear and friction on the treated parts, and improved product release characteristics, particularly with respect to food processing applications. 
         [0040]    The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations of materials and components will be suitable for practicing the present invention. 
         [0041]    Other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.