System for sealing a packaging wrapper

Abstract

A system for sealing a packaging wrapper around an object directs a flow of heated air to end flaps of the wrapper to move the end flaps into sealing contact with a body section of the wrapper to substantially enclose the object. The system includes an oven, a conveyor, a source of heated air and a means for deflecting the flow of heated air to the conveyor to seal end flaps of the wrapper with a body section of the wrapper. In use, an object surrounded by the wrapper body section is moved through the oven on a conveying surface of the conveyor, and heated air is moved through the oven bypassing the conveying surface to a region below the conveying surface. The heated air flow then encounters the means for deflecting the heated air flow, which directs the air flow upward and through the conveying surface to impact and move the end flaps into sealing contact with the wrapper body section.

1 . In a system for sealing a wrapper around an object within an oven, the system including a conveyor having a conveying surface for transporting the object through the oven and a heat source for causing the wrapper surrounding the object to form a sealed wrapper substantially enclosing the object, the conveying surface configured to allow the flow of air therethrough, and the wrapper having a body section surrounding the object and opposing end flaps extending from the body section, the improvement comprising: 
 the heat source comprising a heated air movement source for moving a volume of air through the oven to a region below the conveying surface; and    means, positioned within the oven, for deflecting the heated air flow entering the region below the conveying surface upward and through the conveying surface to impact the opposing end flaps and move the flaps upward into sealing contact with the wrapper body section.    
     
     
         2 . The system of  claim 1 , wherein the conveying surface of the conveyor has opposing lateral side edges, and wherein the heated air movement source comprises: 
 one or more heating elements;    one or more fans moving air over the one or more heating elements; and    a set of dampers positioned adjacent to the lateral side edges of the conveying surface to guide the heated air flow around the conveyor surface to the region below the conveying surface.    
     
     
         3 . The system of  claim 1 , wherein the means for deflecting the heated air flow comprises an end seal deflector having a mounting member and a deflecting member extending at an angle from the mounting member.  
     
     
         4 . The system of  claim 3 , wherein the mounting member comprises a first plate having one or more holes to facilitate a fastener being extended therethrough for securing the mounting member to a structure within the oven, and the deflecting member comprises a second plate extending from the first plate at an angle of between about 30 to 60 degrees.  
     
     
         5 . The system of  claim 3 , wherein the mounting member has an impacting surface, and wherein the end seal deflector is mounted such that an angle α formed by the intersection of a plane of the impacting surface and a plane of the conveying surface is about 30 to 60 degrees measured counterclockwise from the plane of the conveying surface.  
     
     
         6 . The system of  claim 1 , wherein the conveying surface comprises a conveyor chain.  
     
     
         7 . The system of  claim 1 , wherein the object is a bundle of roofing shingles having opposing end regions, and wherein the flaps in sealing contact with the wrapper body section substantially cover exposed areas of the bundle end regions.  
     
     
         8 . An end seal deflector for guiding a flow of heated air in an oven upward through a porous conveying surface of a conveyor upon which a partially wrapped object is positioned, comprising: 
 a mounting member for mounting the deflector within the oven; and    a deflecting member extending at an angle from the mounting member;    whereby a flow of heated air encountering the deflecting member is directed through the conveying surface to impact end flaps of a wrapper surrounding the object and move the end flaps into sealing contact with a body section of the wrapper to form a sealed wrapper substantially enclosing the object.    
     
     
         9 . The deflector of  claim 8 , wherein the mounting member comprises a first plate having one or more holes to facilitate a fastener being extended therethrough for securing the mounting member to a structure within the oven, and the deflecting member comprises a second plate extending from the first plate at an angle of between about 30 to 60 degrees.  
     
     
         10 . The deflector of  claim 8 , wherein the deflector is generally V-shaped.  
     
     
         11 . The deflector of  claim 8 , wherein the deflector is formed of sheet metal.  
     
     
         12 . A system for improving the end seal of a wrapped object, the object having a wrapper body surrounding the object with opposing end flaps extending from the body, the system comprising: 
 an oven;    a conveyor positioned in the oven and having a conveying surface operative to convey an object through the oven, the conveying surface configured to allow air flow therethrough;    a source of heated air for moving a volume of air through the oven bypassing the conveying surface to a region below the conveying surface; and    means, positioned within the oven, for deflecting the heated air flow entering the region below the conveying surface upward and through the conveying surface to impact the opposing end flaps and move the flaps upward into sealing contact with the wrapper body.    
     
     
         13 . The system of  claim 12 , wherein the conveying surface of the conveyor has opposing lateral side edges, and wherein the source of heated air comprises: 
 one or more heating elements;    one or more fans moving air over the one or more heating elements; and    a set of dampers positioned adjacent to the lateral side edges of the conveying surface to guide the heated air flow around the conveyor surface to the region below the conveying surface.    
     
     
         14 . The system of  claim 12 , wherein the means for deflecting the heated air flow comprises an end seal deflector having a mounting member and a deflecting member extending at an angle from the mounting member.  
     
     
         15 . The system of  claim 14 , wherein the mounting member comprises a first plate having one or more holes to facilitate a fastener being extended therethrough for securing the mounting member to a structure within the oven, and the deflecting member comprises a second plate extending from the first plate at an angle of between about 30 to 60 degrees.  
     
     
         16 . The system of  claim 14 , wherein the mounting member has an impacting surface, and wherein the end seal deflector is mounted such that an angle α formed by the intersection of a plane of the impacting surface and a plane of the conveying surface is about 30 to 60 degrees measured counterclockwise from the plane of the conveying surface.  
     
     
         17 . A process for packaging an object with a plastic wrapper in an oven, the wrapper having a body section and opposed end flaps extending therefrom to form a sealed wrapper substantially enclosing the object, the process comprising the steps of: 
 conveying the object through an oven on a conveying surface, the object having a body portion and opposed end regions, the plastic wrapper body section surrounding the body portion such that the opposed end flaps extend generally away from a lower region of the opposed end regions of the object;    generating and moving heated air through the oven bypassing the conveying surface to a region below the conveying surface;    deflecting the heated air reaching the region below the conveying surface upwards and through the conveying surface to impact and move the opposed end flaps upward into contact with the wrapper body section substantially over the opposed end regions of the object; and    sealing the opposed end flaps with the wrapper body section.    
     
     
         18 . The process of  claim 17 , wherein sealing the opposed end flaps comprises maintaining the deflected flow of heated air on the end flaps at a mass flow rate and for a time sufficient to cause the end flaps to bond with the wrapper body section.  
     
     
         19 . The process of  claim 17 , wherein the object is a bundle of roofing shingles.  
     
     
         20 . The process of  claim 17 , wherein the conveying surface has opposing lateral side edges, and wherein the heated air moved through the oven bypasses the conveying surface by encountering a set of dampers positioned adjacent to the lateral side edges of the conveying surface to guide the heated air flow around the conveyor surface to the region below the conveyor surface.  
     
     
         21 . The process of  claim 17 , wherein the heated air reaching the region below the conveying surface is deflected by an end seal deflector having a mounting member and a deflecting member extending at an angle from the mounting member.  
     
     
         22 . The process of  claim 21 , wherein the mounting member comprises a first plate having one or more holes to facilitate a fastener being extended therethrough for securing the mounting member to a structure within the oven, and the deflecting member comprises a second plate extending from the first plate at an angle of between about 30 to 60 degrees.  
     
     
         23 . The process of  claim 17 , wherein the conveying surface comprises a conveyor chain.