Abstract:
Health considerations mandate continuous and thorough cleaning of modular conveyor belts used in the food processing industry. A modular belt cleaning system is provided having a sleeve bearing slidable over a supply pipe, and having apertures for engaging nozzles in the supply pipe. A sprocket is mountable over the sleeve bearing. Depressible retainers are disclosed to permit installation and removal of a sprocket over the sleeve bearing.

Description:
CROSS-REFERENCE TO RELATED ART  
       [0001]     This application claims priority to U.S. Provisional Application Ser. No. 60/727,149. 
     
    
     TECHNICAL FIELD OF THE INVENTION  
       [0002]     The invention relates generally to a conveyor system cleaning apparatus and, more particularly, to a cleaning system for a meat transporting conveyor system.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the meat and meat packing industries, conveyor belts and conveyor systems are commonly utilized to transport meat in processing plants.  
         [0004]     The most frequently employed conveyor systems comprise a number of interlocking conveyor modules linked together to form a continuous conveyor belt, which is driven by a sprocket. Some examples of these types of conveyor systems are U.S. Pat. Nos. 4,925,016, 6,423,279, 3,602,364, 4,072,062, 4,080,842, 4,213,527, and 4,556,142. Some systems both drive the belt and track the belt with the sprockets.  
         [0005]     In the meat and meat packing industries, cleanliness is paramount to the entire operation. Meat and meat byproducts, by their very nature, carry bacteria. These bacteria can be harmful to humans and/or animals that eventually consume the meat or meat products. It is very difficult to eliminate all of the bacteria during processing, so measures are taken to control bacterial populations within the meat and meat products.  
         [0006]     One method of controlling bacterial growth is frequent cleaning of the machines and apparatuses in contact with meat. By frequently cleaning the machines and apparatuses, the size and development of bacterial colonies can be reduced and managed.  
         [0007]     In meat processing operations, the conveyor belts are constantly in contact with meat and meat byproducts. Because of the regularity of use, it is essential to frequently clean the conveyor belts. Conventional conveyor belt systems in the meat industry are not uniform elastic belts with continuous contact surface. Instead, the belts are commonly formed of interlocking modules that are propelled and tracked by sprockets.  
         [0008]     Referring to  FIG. 1  of the drawings, the reference numeral  10  generally designates a conventional conveyor system. Conveyor system  10  comprises a conveyor belt  20  and a sprocket  30 . Conveyor belt  20  is comprised of a plurality of interlocking modules  40 . Because conveyor belt  20  lacks a continuous surface, it is very easy for meat and meat byproducts to become wedged between interlocked modules  40  and decay. In addition, meat and meat byproducts can become wedged between sprocket  30  and the undersides of conveyor modules  40 . Absent continuous cleaning efforts, hazardous biological colonies would grow unabated and present an unacceptable health risk.  
         [0009]     To effectively provide continuous cleaning, an automated cleaning system must be incorporated into conveyor system  10 . Specifically, an apparatus is required that can spray a cleaning/disinfecting solution on belt  20  to wash away or kill bacteria caused by meat particles lodged between modules  40  and between modules  40  and sprocket  30  of conveyor system  10 .  
         [0010]     To clean conveyor system  10 , it is known to place a cleaning system underneath belt  20  and utilize spray nozzles to clean the system. Examples of such cleaning systems are U.S. Pat. Nos. 6,740,172 and 3,016,235. There are a number of positions underneath belt  20  whereby a cleaning system can be positioned. However, it is more likely to have the greatest effect where the interlocking modules  40  pivot apart from each other. Pivoting of the interlocking modules  40  occurs at the locations where belt  20  is propelled by and/or tracked by sprocket  30 .  
         [0011]     One problem associated with positioning a cleaning system beneath or at the center of a rotating sprocket is that the sprocket will wear against the cleaning system and they are not easily repaired. Another problem is that frictional rotation of Polyvinyl Chloride (PVC) materials against stainless steel results in a leaching action that stains the surface of the stainless steel and causes the build-up of a black tarry substance. Therefore, there is a need for a method and/or apparatus for cleaning a conveyor system that is wear resistant, resists leaching and is easily repaired.  
       SUMMARY OF THE INVENTION  
       [0012]     In accordance with a preferred embodiment of the present invention, a conveyor belt cleaning system is provided. Within the cleaning system is a supply pipe for carrying a cleaning and/or disinfecting solution, such as water or a solvent. A plurality of removable spray nozzles are secured to the supply pipe. A removable sleeve bearing is located on the supply pipe. One or more apertures are located on the sleeve bearing for engaging a spray nozzle to prevent rotation of the sleeve bearing. A sprocket is rotatably mounted on the sleeve bearing.  
         [0013]     In another preferred embodiment, the sleeve bearing is located between two spray nozzles. In another preferred embodiment, the supply pipe is comprised of stainless steel. In another preferred embodiment, the sleeve bearing is comprised of plastic. In a still more preferred embodiment, the sleeve bearing is comprised of Polyvinyl Chloride (PVC).  
         [0014]     In another preferred embodiment, the apertures in the sleeve bearing are substantially semi-circular and located on the ends of the sleeve bearing. In another preferred embodiment, the removable spray nozzles are comprised of stainless steel. In another preferred embodiment, each removable spray nozzle has a substantially linear spray pattern. In a more preferred embodiment, a flow straightener is attached to each nozzle.  
         [0015]     In another preferred embodiment, retainers are provided on the sleeve bearing, having sloped risers and a relief partially inscribing the perimeter of the retainer. In this embodiment, depression of the retainer permits installation and removal of the sprocket, and the retainer then limits lateral movement of the installed sprocket.  
         [0016]     In  FIGS. 10 and 11 , another preferred embodiment is illustrated in which system  100  includes centering ribs. In this embodiment, the ribs center the sleeve bearing on the supply pipe. In another preferred embodiment, the ribs can be located so as to optionally prevent or allow depression of the retainer when installed on the supply pipe.  
         [0017]     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.  
         [0018]     It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements.  
         [0020]     The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.  
         [0021]      FIG. 1  is an isometric view of a conventional conveyor belt system.  
         [0022]      FIG. 2  is an isometric side view of the cleaning system in accordance with a preferred embodiment of the present invention.  
         [0023]      FIG. 3  is an isometric top view of the cleaning system of  FIG. 2 .  
         [0024]      FIG. 4  is a front view of the nozzle in accordance with a preferred embodiment of the present invention.  
         [0025]      FIG. 5  is a side view of the nozzle of  FIG. 4 .  
         [0026]      FIG. 6  is a bottom view of the nozzle of  FIG. 4 .  
         [0027]      FIG. 7  is a top view of the nozzle of  FIG. 4 .  
         [0028]      FIG. 8  is an isometric side view of another preferred embodiment of the cleaning system, having a retainer located on the sleeve bearing.  
         [0029]      FIG. 9  is an isometric top view of the cleaning system of  FIG. 8 .  
         [0030]      FIG. 10  is an end view of another preferred embodiment of the cleaning system, having retainers and centering ribs located on the supply pipe.  
         [0031]      FIG. 11  is a cross-sectional view of the sleeve bearing embodiment illustrated in  FIG. 10 .  
         [0032]      FIG. 12  is an end view of another preferred embodiment of the cleaning system, having retainers and centering ribs located on the supply pipe, with the centering ribs located aligned with the retainers.  
         [0033]      FIG. 13  is a cross-sectional view of the sleeve bearing embodiment illustrated in  FIG. 12 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]     In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail.  
         [0035]     The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.  
         [0036]     Referring to  FIGS. 2 and 3  of the drawings, the reference numeral  100  generally designates the cleaning system. Cleaning system  100  has a supply pipe  102 . Nozzles  104  are removably connected to supply pipe  102 . In the preferred embodiment, nozzles  104  are connected to supply pipe  102  by threaded pipe connection. A removable sleeve bearing  106  is slidably located over supply pipe  102 . An aperture  108  is located on sleeve bearing  106 . In another preferred embodiment, aperture  108  is located on an end of sleeve bearing  106 . In this embodiment, as illustrated, aperture  108  is preferably semicircular.  
         [0037]     In a preferred embodiment, each end of sleeve bearing  106  has an aperture  108 . Apertures  108  engage nozzles  104  to prevent rotation of sleeve bearing  106  relative to supply pipe  102 . In the preferred embodiment, a sprocket  30  is rotatably mounted on sleeve bearing  106 . As illustrated in  FIG. 3 , sprocket  30  is located between nozzles  104 . In this preferred embodiment, engagement of apertures  108  with nozzles  104  prevents rotation of sleeve bearing  106 .  
         [0038]     In the preferred embodiment, supply pipe  102  is comprised of stainless steel. Also in the preferred embodiment, sleeve bearing  106  is comprised of plastic, and preferably Polyvinyl Chloride (PVC).  
         [0039]     In  FIGS. 4-7 , nozzles  104  are shown in greater detail. In the preferred embodiment, nozzle  104  has a spray head  202 . A tool grip  204  is located beneath spray head  202 . A threaded section  206  is located beneath tool grip  204 . Threaded section  206  is adapted to thread connect with a threaded aperture in supply pipe  102 . Spray head  202 , tool grip  204  and threaded section  206  are substantially hollow to provide a fluid channel for receiving fluid carried by supply pipe  102 . Fluid flowing through supply pipe  102  exits an exit port  210  in spray head  202 .  
         [0040]     In a more preferred embodiment, a flow straightener  208  is located within the interior of nozzle  104 . In the preferred embodiment, spray nozzle  104  is comprised of stainless steel. Spray nozzles  104  of the type illustrated are commercially available, such as model MEG ¼ NPT from Spraying Systems Co., P.O. Box 7900, Wheaton, Ill. 60189-7900 USA.  
         [0041]     In  FIGS. 8-13 , a more preferred embodiment is illustrated in which system  100  includes retainers  110  located on sleeve bearing  106 . In this embodiment, engagement of sprocket  30  with retainers  110  limits lateral movement of sprocket  30  on sleeve bearing  106 . In the preferred embodiment, retainers  110  are sloped, and have a substantially vertical riser  114  at its end. Risers  114  extend beyond the exterior surface of sleeve bearing  106 . Interference with risers  114  limits lateral movement of sprocket  30  to a predetermined and acceptable amount.  
         [0042]     In the preferred embodiments illustrated in  FIGS. 11 and 13 , opposing retainers  110  are provided on opposite sides of sprocket  30 . In an optional embodiment, multiple retainers  110  are located at a lateral position on sleeve bearing  106 , for engagement with one side of sprocket  30 . In this embodiment, retainers  110  are preferably located in angularly spaced relationship, such as seen in  FIGS. 8, 10 , and  11 .  
         [0043]     Also in the preferred embodiment, reliefs  112  in sleeve bearing  106  partially inscribe the perimeter of retainers  110 . In this embodiment, depression of retainers  110  through reliefs  112  lowers risers  114  substantially even with the exterior surface of sleeve bearing  106  to permit installation and removal of sprocket  30  on sleeve bearing  106 .  
         [0044]     In  FIGS. 10 and 11 , another preferred embodiment is illustrated in which system  100  includes centering ribs  120  located on the interior surface of sleeve bearing  106 . In the embodiment illustrated in  FIGS. 10 and 11 , a plurality of centering ribs  120  are positioned laterally and axially so as not to interfere with the operation of retainers  110 . In this embodiment, three or four centering ribs are preferred, although more or less can be used.  
         [0045]     In  FIGS. 12 and 13 , another preferred embodiment is illustrated in which system  100  includes centering ribs  120  located on the interior surface of sleeve bearing  106 . In the embodiment illustrated in  FIGS. 12 and 13 , a plurality of centering ribs  120  are positioned laterally and axially so as to interfere with the operation of retainers  110  when sleeve bearing  106  is installed on supply pipe  102 . Also in this embodiment, three or four centering ribs are preferred, although more or less can be used.  
         [0000]     Operation of the Preferred Embodiments  
         [0046]     Referring to  FIGS. 2 and 3  of the drawings, the reference numeral  100  generally designates the cleaning system. Cleaning system  100  has a supply pipe  102 . Nozzles  104  are removably connected to supply pipe  102 . In the preferred embodiment, nozzles  104  are connected to supply pipe  102  by threaded pipe connection.  
         [0047]     Cleaning system  100  operates by having pressurized water or some other pressurized solvent or disinfecting solution travel along the length of supply pipe  102 . Typically, supply pipe  102  is standard ¼-inch, schedule 40 stainless steel pipe. The direction of the flow of the water or the solvent is transverse with respect to the direction of the motion of a conveyor belt, which is driven by and/or tracked by sprocket  30 .  
         [0048]     In the present invention, sleeve bearing  106  provides a wear surface. With conventional systems, sprocket  30  is designed to rotate directly on supply pipe  102 . The continual rotation of sprocket  30  on supply pipe  102  in conventional systems generates a leaching effect between the stainless steel and the PVC sprocket  30 , generating a black tarry contaminating substance at their interface. To alleviate this problem, sleeve bearing  106  is designed to slide over supply pipe  102  and prevent relative motion between the stainless steel surface of supply pipe  102  and the PVC surface of sprocket  30 .  
         [0049]     To prevent wear between the materials, rotation of sleeve bearing  106  must be prevented. To prevent rotation of sleeve bearing  106 , sleeve bearing  106  can be internally sized for an interference fit relationship with supply pipe  102 . However, this creates a system that is very difficult to assemble and disassemble. In the preferred embodiment of the present invention, apertures  108  are provided in sleeve bearing  106 , and located in alignment with nozzles  104 . Apertures  108  engage nozzles  104  to prevent rotation of sleeve bearing  106  relative to supply pipe  102 .  
         [0050]     In another preferred embodiment, aperture  108  is located on an end of sleeve bearing  106 . In this embodiment, as illustrated, aperture  108  is preferably semicircular. In another preferred embodiment, each end of sleeve bearing  106  has an aperture  108 . Apertures  108  engage nozzles  104  to prevent rotation of sleeve bearing  106  relative to supply pipe  102 .  
         [0051]     The geometry of apertures  108 , however, can vary, so that there are a variety of other shapes that can encompass the geometry of apertures  108 . Additionally, a bevel can be added along the edge of apertures to reduce stress concentrations, add clearance for tools for installing and removing nozzles  104 , and further reduce the potential for any cracking or wear of sleeve bearing  106 .  
         [0052]     Sprocket  30  is rotatably mounted on sleeve bearing  106 . As illustrated in  FIG. 3 , sprocket  30  is located between nozzles  104 . In this preferred embodiment, engagement of sprocket  30  with nozzles  104  limits lateral movement of sprocket  30 .  
         [0053]     As the pressurized water or solvent enters supply pipe  102 , it is forced through nozzles  104 . In  FIGS. 4-7 , nozzles  104  are shown in greater detail. Each of the nozzles has a spray  202 , a grip  204 , and a threaded section  206 .  
         [0054]     In order to utilize nozzles  104 , threaded section  206  is adapted to engage a like-threaded aperture on supply pipe  102 . Thus, nozzles  104  can be secured into position by rotating nozzles  104  in the direction of the thread on threaded section  206 . Due to the preference for having a watertight seal, more than hand torquing is generally necessary. Tool grip  204  is thus shaped for use with a conventional wrench. The ability to employ a wrench allows threaded section  206  of nozzles  104  to be sufficiently torqued into place to provide a watertight seal.  
         [0055]     Additionally, each of the spray  202 , grip  204 , and threaded section  206  is substantially hollow to provide a fluid channel for the pressurized water or other pressurized solvent carried by supply pipe  102  to exit. However, because the flow of the water or solvent is substantially orthogonal to the exit direction of the water or solvent, it is not uncommon to have turbulent flow within the nozzles  104 . Turbulent flow within the nozzles  104  can cause a variety of problems, for example cavitation and uneven flow across an exit port  210 . These problems can result in reduced cleaning performance and increased likelihood that meat or meat byproduct could remain on portions of conveyor belt  20 .  
         [0056]     One way to improve flow quality is to employ flow straightener  208 . Flow straightener  208  is located within the cavity located within threaded section  206 . In particular, flow straightener  208  is shaped as a figure eight; however, a variety of other geometries can also be employed, such as a plurality of straight pipes. By utilizing flow straightener  208 , turbulence and pressure loss through each of nozzles  104  can be substantially reduced.  
         [0057]     In addition to employing flow straightener  208 , the geometry of exit port  210  can also be important to cleaning performance. In the preferred embodiment, nozzles  104  employ a linear exit port; however, there are a variety of other geometries that can be employed, such as circular apertures. The combination of exit port  210  and flow straightener  208  allows for providing a reliable cleaning performance through nozzles  104 .  
         [0058]     In  FIGS. 8-13 , a more preferred embodiment is illustrated in which system  100  includes retainers  110  located on sleeve bearing  106 . In this embodiment, engagement of sprocket  30  with retainers  110 , rather than with nozzles  104 , limits lateral movement of sprocket  30  on sleeve bearing  106 . In the preferred embodiment, each sloped retainer  110  has a substantially vertical riser  114  formed on its end. Risers  114  extend beyond the exterior surface of sleeve bearing  106  and engage sprocket  30  to limit lateral movement of sprocket  30 .  
         [0059]     Reliefs  112  in sleeve bearing  106  partially inscribe the perimeter of retainers  110 , sufficient as to allow depression of retainers  110 . Depression of retainers  110  through reliefs  112  lowers risers  114  to a point approximately even with the exterior surface of sleeve bearing  106  to permit installation and removal of sprocket  30  on sleeve bearing  106 . The sloped portion of retainers  110  permits easy installation of sprocket  30  on sleeve bearing  106 . In the preferred embodiment, the inside diameter of sprocket  30  can be used to depress retainers  110  and permit sprocket  30  to slide over retainers  110 . Once past retainers  110 , retainers  110  expand to limit lateral movement of sprocket  30 .  
         [0060]     In the embodiment disclosed in  FIGS. 10 and 11 , centering ribs  120  located on the interior surface of sleeve bearing  106  are positioned laterally and axially so as to avoid interference with the operation of retainers  110  when sleeve bearing  106  is located on supply pipe  102 . In this embodiment, depression of retainers  110  can be performed with sleeve bearing  106  installed on supply pipe  102 . The advantage of this embodiment is that it permits installation and removal of sprocket  30  without removing sleeve bearing  106  from supply pipe  102 .  
         [0061]     In the embodiment disclosed in  FIGS. 12 and 13 , centering ribs  120  located on the interior surface of sleeve bearing  106  are positioned laterally and axially so as to interfere with the operation of retainers  110  when sleeve bearing  106  is located on supply pipe  102 . In this embodiment, depression of retainers  110  cannot be performed with sleeve bearing  106  installed on supply pipe  102 . The advantage of this embodiment is that it prohibits undesired removal of sprocket  30  when sleeve bearing  106  is installed on supply pipe  102 .  
         [0062]     An advantage of the present invention is that it is simple, safe, and durable. Another advantage of the present invention is that it is inexpensive to manufacture. Another advantage of the present invention is that it provides an easily installed, removed, and repaired cleaning system. Another advantage of the present invention is that it provides a cleaning system that can be installed using only the tools needed to install nozzles  104 .  
         [0063]     Another advantage of the present invention is that it provides a cleaning system that prevents buildup of leached elements between stainless steel and plastic or PVC surfaces. Other advantages of the present invention will become apparent from the above descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.  
         [0064]     It will be readily apparent to those skilled in the art that the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention.  
         [0065]     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.