System and method for electropolishing or electroplating conveyor belts

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.

BACKGROUND

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.

2. Description of Related Art

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

DETAILED DESCRIPTION

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.

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,FIG. 1is 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 belt105. As illustrated inFIG. 1, two housings115A and115B are positioned at the edges of conveyor belt105in order to electropolish or electroplate edge links120A and edge links120B, respectively. In some embodiments, however, only a single housing115A or115B can be positioned on an edge of conveyor belt105to electropolish or electroplate only one of edge links120A or edge links120B, respectively. It is understood that housing115B is cutaway inFIG. 1for purposes of explanation only, and that in practice, the exterior of housing115B resembles housing115A. Further, it is understood that the interior of housing115A resembles that shown with respect to housing115B. Although not shown inFIG. 1, it is contemplated that other features of the conveyor belt may be electropolished or electroplated with or instead of edge links120A and edge links120B, such as edge guards or lane dividers.

Electrical contacts110A and110B placed on conveyor belt105cause the conveyor belt105to become an anode (in the case of electropolishing) or cathode (in the case of electroplating). Force may be placed on electrical contact110A and/or electrical contact110B to ensure consistent contact with conveyor belt105and 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 contact110A and/or electrical contact110B are movable or floating to accommodate variations in the dimensions of conveyor belt105.

In this embodiment, an electrical conductor125B is placed in housing115B 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 housing115A to serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating). In this embodiment, electrical conductor115B is placed proximate to the edge of edge links120B in order to target polishing or plating at the weld135B of conveyor belt105. However, it is contemplated that electrical conductor115B can be placed in any position proximate to any particular area to be electropolished or electroplated.

In one embodiment, housing115A and housing115B 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 housing115A or housing115B. Housing115A, housing115B and the electrical conductors (i.e., the electrical conductor internal to housing115A and electrical conductor125B) can be sized and positioned such that the surface of the electrical conductors are equidistant from all surfaces of edge links120A and edge links120B for even polishing. Nonconductive wear surfaces may be placed in housing115A and housing115B in any practical configuration, such as a bushing or perforated liner, to prevent contact between conveyor belt105and the electrical conductors, to prevent contact between conveyor belt105and the electrical conductors while allowing current to flow between the electrical conductors and conveyor belt105.

Although shown as rectangular and elongated in shape, it is contemplated that housing115A and housing115B can be of any shape or size suitable to achieve electropolishing or electroplating as described herein. Further, housing115A and housing115B can be constructed as a single body, or can be made of separable components, such as a body and removable lid.

Electrolyte may be introduced at any point along the length of housings115A and115B. In this embodiment, electrolyte is introduced into housing115A via inlet130A. It is understood that electrolyte is introduced into housing115B via a similar inlet (not shown). Electrolyte may flow in either direction through housings115A and115B, i.e., in the direction of travel of conveyor belt105through housings115A and115B, or counter to the direction of travel of conveyor belt105through housings115A and115B.

In one embodiment, housings115A and115B are open at the ends to allow electrolyte to flow out and to allow conveyor belt105to 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 housings115A and115B are provided with seals140A and140B, respectively, so that the housings115A and115B are flooded to a level that provides effective electropolishing or electroplating. Seals140A and140B 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.

FIG. 2is 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 belt205having a plurality of center links220to be electropolished or electroplated. Center links220are any links positioned between the edges of conveyor belt205, and do not necessarily need to be centered between the edges of conveyor belt205. Center links220are positioned laterally to create a desired turn radius and to control expansion and collapse of the edge links of conveyor belt205. A single housing215is positioned along the width of the conveyor belt205in order to electropolish or electroplate center links220. It is understood that housing215is cutaway inFIG. 2for purposes of explanation only, and that housing215is rectangular in shape in use. Although not shown inFIG. 2, it is contemplated that other features of the conveyor belt may be electropolished or electroplated with or instead of center links220, such as edge guards or lane dividers. Further, although shown and described with respect to a single housing215and a single column of center links220, it is contemplated that multiple columns of center links220may be present, or multiple other features to be electropolished or electroplated, as well as their accompanying housings.

Electrical contacts210A and210B are placed on conveyor belt205in a manner similar to that described with respect to electrical contacts110A and110B ofFIG. 1. An electrical conductor225is placed in housing215to serve as a cathode (in the case of electropolishing) or an anode (in the case of electroplating). In this embodiment, electrical conductor225is placed on the bottom of housing215, underneath both of the welded edges235A and235B of center links220. However, it is contemplated that electrical conductor225can be placed in any position proximate to any particular area to be electropolished or electroplated.

As with respect toFIG. 1, housing215can 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 housing215. Housing215and electrical conductor225can be sized and positioned such that the surface of the electrical conductor225is equidistant from all surfaces of center links220for even polishing. Nonconductive wear surfaces may be placed in housing225in any practical configuration, such as a bushing or perforated liner, to prevent contact between conveyor belt205and the electrical conductors, to prevent contact between conveyor belt205and the electrical conductors while allowing current to flow between the electrical conductors and conveyor belt205.

Although shown as rectangular and elongated in shape, it is contemplated that housing215can be of any shape or size suitable to achieve electropolishing or electroplating as described herein. Further, housing215can be constructed as a single body, or can be made of separable components, such as a body and removable lid.

Electrolyte is introduced via inlet230at a central location with respect to the length and width of housing215, as is described with respect toFIG. 1. Electrolyte may flow in either direction through housing215, i.e., in the direction of travel of conveyor belt205through housing215, or counter to the direction of travel of conveyor belt205through housing215.

In this embodiment, housing215is open at the ends to allow electrolyte to flow out and to allow conveyor belt205to pass through. As is described above with respect toFIG. 1, a separate orifice may instead be provided for the electrolyte outflow. Housing215is provided with a seal240so that the housing215is flooded to a level that provides effective electropolishing or electroplating, while minimizing electrolyte loss. In this embodiment, seal240is positioned on both sides of center links220. 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 ofFIG. 1with that ofFIG. 2.

FIG. 3is 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 belt305. To create a continuous electropolishing or electroplating process, conveyor belt305is unrolled from an in-feed roll340into cleaning station345, traveling in a direction A. Cleaning station345cleans the edge links of conveyor belt305and degreases them, for example. Conveyor belt305is then rinsed at rinse station350.

Electroplating or electropolishing is achieved at electroplating/electropolishing stations355. Although illustrated with two electroplating/electropolishing stations355, it is contemplated that only a single electroplating/electropolishing station355can be provided, or multiple electroplating/electropolishing stations355can be provided in series. Electroplating/electropolishing stations355have housings315A to polish one edge of the conveyor belt, as well as housings opposite to housing315A (not shown) to polish the opposite edge of conveyor belt355. It is contemplated that housings315A, as well as the opposing housings, may be similar or identical to housings115A and115B, respectively, ofFIG. 1. Further, although shown and described herein only with respect to housings315A, it is contemplated that a similar or identical process may be carried out with respect to the opposing housings. Although not shown inFIG. 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 belt305, such as edge guards or lane dividers.

Electrical contacts placed on conveyor belt305cause the conveyor belt to become an anode (in the case of electropolishing) or cathode (in the case of electroplating). Electrical conductors are placed in housings315A to serve as a cathode (in the case of electropolishing) or anode (in the case of electroplating). Electrolytic solution is provided via inlets330A to housings315A, immersing the edges of conveyor belt305within the housings315A in electrolytic solution.

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 belt305, coating conveyor belt305and depositing a layer of metallic material on the surface of conveyor belt305.

With respect to electropolishing, a current is applied to conveyor belt305, oxidizing the metal atoms on the surface of conveyor belt305and 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 belt305.

Once conveyor belt305has been electropolished or electroplated, it is moved into post-treatment station360(where it undergoes, e.g., a nitric acid rinse), then undergoes a final rinse at rinse station365. Optionally, conveyor belt305can be moved through a dryer (not shown). Conveyor belt305is moved onto take-up roll370. It is contemplated that conveyor belt305can be moved from in-feed roll340to take-up roll370by 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 thatFIG. 3can be modified to instead or additionally electropolish or electroplate center links, if present.

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.

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.