Fusible bung for liquid tanks

Abstract

A fusible bung for sealing an opening in a threaded flange on a liquid container. The bung is formed as a unitary body of polymeric material that includes cylindrical, concentric interior and exterior walls separated by a vent passage and interconnected by a unitary venting fuse. The exterior wall is threaded for mounting of the bung and includes an annular shoulder and separate sealing ring for providing a gas-tight seal to the container flange. The interior wall is supported by the exterior wall via the venting fuse, which is formed during molding of the bung as a thin-walled section of the polymeric material which melts and ruptures at elevated temperatures. The central region within the interior wall can include either a unitary cover member or can have a threaded bore to receive a separate relief valve.

1 . A fusible bung, comprising: 
 a first wall having at least one fastening feature by which said bung can be mounted at an opening in a supporting structure;    a second wall spaced inwardly from said first wall with a vent passage being located between said first and second walls; and    a fusible link interconnecting said first and second walls and closing off said vent passage, wherein said second wall is supported by said fusible link.    
     
     
         2 . A fusible bung as defined in  claim 1 , wherein said fusible link and said walls together comprise a unitary body of polymeric material.  
     
     
         3 . A fusible bung as defined in  claim 2 , wherein said polymeric material comprises HDPE.  
     
     
         4 . A fusible bung as defined in  claim 1 , wherein said fusible link comprises a thin walled section of polymeric material having a thickness of less than or equal to 0.04 inches.  
     
     
         5 . A fusible bung as defined in  claim 4 , wherein said fusible link has a width of less than or equal to 0.312 inches.  
     
     
         6 . A fusible bung as defined in  claim 4 , wherein said first and second walls have a dimension in the thickness direction of said fusible link of at least fifteen times the thickness of said fusible link.  
     
     
         7 . A fusible bung as defined in  claim 1 , wherein said first wall is a cylindrical wall and said fastening feature comprises threads located on said first wall.  
     
     
         8 . A fusible bung as defined in  claim 7 , further comprising at least one safety vent formed as a radial opening extending through said threads in said first wall.  
     
     
         9 . A fusible bung as defined in  claim 1 , further comprising a cover member located within a central region of said second wall, wherein said first and second walls, said fusible link, and said cover member each comprise unitary portions of a single body.  
     
     
         10 . A fusible bung as defined in  claim 1 , further comprising an opening located inwardly within said second wall for receiving a relief valve.  
     
     
         11 . A fusible bung as defined in  claim 10 , wherein said first and second walls comprise concentric cylindrical walls said second wall includes a threaded bore for receiving the relief valve.  
     
     
         12 . A fusible bung, comprising: 
 a first wall;    a second wall spaced inwardly from said first wall with a vent passage being located between said first and second walls; and    a fusible link interconnecting said first and second walls and closing off said vent passage, wherein, at lower temperatures said fusible link prevents the escape of gases through said vent passage and, at higher temperatures said fusible link melts, thereby permitting the gases to escape through said vent passage.    
     
     
         13 . A fusible bung as defined in  claim 12 , wherein said first wall includes a threaded cylindrical portion for mounting of said fusible bung, and wherein said second wall is supported by said fusible link.  
     
     
         14 . A fusible bung as defined in  claim 12 , wherein said fusible link and said walls together comprise a unitary body of polymeric material.  
     
     
         15 . A fusible bung as defined in  claim 14 , wherein said polymeric material comprises HDPE.  
     
     
         16 . A fusible bung as defined in  claim 12 , wherein said fusible link comprises a thin walled section of polymeric material having a thickness of less than or equal to 0.04 inches.  
     
     
         17 . A fusible bung as defined in  claim 16 , wherein said fusible link has a width of less than or equal to 0.312 inches.  
     
     
         18 . A fusible bung as defined in  claim 16 , wherein said first and second walls have a dimension in the thickness direction of said fusible link of at least fifteen times the thickness of said fusible link.  
     
     
         19 . A fusible bung as defined in  claim 12 , wherein said first wall is a cylindrical wall and includes an annular shoulder, and wherein said bung further comprises a sealing ring attached to said first wall at said shoulder.  
     
     
         20 . A fusible bung as defined in  claim 19 , wherein said shoulder includes an annular rib that engages said sealing ring during tightening of said bung.  
     
     
         21 . A fusible bung as defined in  claim 12 , further comprising a plurality of tool engaging surfaces located at said first wall for tightening and loosening of said bung using a tool.  
     
     
         22 . A fusible bung as defined in  claim 21 , wherein said tool engaging surfaces comprise notches located about the periphery of said first wall.  
     
     
         23 . A fusible bung for sealing an opening in a liquid container, comprising: 
 a circular body;    a sealing ring attached to said body, wherein said body includes at least one fastening feature such that said body can be attached over said opening with said sealing ring providing a gas-tight seal of said bung to said opening; and    a venting fuse unitary with said body and being located radially inwardly of said sealing ring.    
     
     
         24 . A fusible bung as defined in  claim 23 , wherein said body includes cylindrical first and second concentric walls interconnected by said venting fuse.  
     
     
         25 . A fusible bung as defined in  claim 24 , wherein said first wall includes an annular shoulder with said sealing ring being seated on said shoulder.  
     
     
         26 . A fusible bung as defined in  claim 25 , wherein said shoulder includes an annular rib adjacent said sealing ring.  
     
     
         27 . A fusible bung as defined in  claim 23 , wherein said venting fuse comprises a thin walled section of polymeric material having a thickness of less than or equal to 0.04 inches.  
     
     
         28 . A fusible bung as defined in  claim 27 , wherein said venting fuse has a width of less than or equal to 0.312 inches.  
     
     
         29 . A fusible bung as defined in  claim 27 , wherein said body includes cylindrical first and second concentric walls interconnected by said venting fuse and wherein said first and second walls have a dimension in the thickness direction of said venting fuse of at least fifteen times the thickness of said venting fuse.  
     
     
         30 . A fusible bung comprising a unitary body having a thin walled section of fusible material bounded on opposite sides by thicker wall sections of said material, said thin walled section of fusible material comprising a fuse having a thickness and having a width that is greater than said thickness.  
     
     
         31 . A fusible bung as defined in  claim 30 , wherein said fuse comprises a thin walled section of polymeric material having a thickness of less than or equal to 0.04 inches.  
     
     
         32 . A fusible bung as defined in  claim 31 , wherein said fuse has a width of less than or equal to 0.312 inches.  
     
     
         33 . A fusible bung as defined in  claim 30 , wherein said thicker wall sections each have a dimension in the thickness direction of said fuse of at least fifteen times the thickness of said fuse.  
     
     
         34 . A fusible bung as defined in  claim 30 , wherein said fusible material comprises HDPE.  
     
     
         35 . A fusible bung for sealing an opening in a threaded flange on a liquid container, comprising: 
 a cylindrical exterior wall extending axially and having a threaded portion located near an axial end of said exterior wall;    a cylindrical interior wall spaced radially inwardly from said exterior wall;    a cylindrical vent passage located between said interior and exterior walls;    a venting fuse forming a third wall extending across said vent passage and interconnecting said first and second walls; and    at least one safety vent comprising a radial opening in said threaded portion of said exterior wall.    
     
     
         36 . A fusible bung as defined in  claim 35 , wherein said venting fuse and said walls together comprise a unitary body of polymeric material.  
     
     
         37 . A fusible bung as defined in  claim 36 , wherein said polymeric material comprises HDPE.  
     
     
         38 . A fusible bung as defined in  claim 35 , wherein said venting fuse has a width and has a thickness that is less than its width, and wherein said interior and exterior walls have a dimension in the thickness direction of said venting fuse of at least fifteen times the thickness of said venting fuse.  
     
     
         39 . A fusible bung for sealing an opening in a threaded flange on a liquid container, comprising: 
 a cylindrical exterior wall extending axially and having a threaded portion located near an axial end of said exterior wall;    a cylindrical interior wall spaced radially inwardly from said exterior wall and extending axially for a shorter distance than said exterior wall;    a shoulder extending from said exterior wall;    a sealing ring located at said shoulder;    a vent passage interposed between said interior and exterior walls;    an annular venting fuse comprising a thin walled section of polymeric material which interconnects and is unitary with said interior and exterior walls; and    at least one safety vent comprising a radial opening in said threaded portion of said exterior wall.    
     
     
         40 . A fusible bung as defined in  claim 39 , wherein said polymeric material comprises HDPE and said venting fuse has a thickness of less than or equal to 0.04 inches.  
     
     
         41 . A fusible bung as defined in  claim 39 , further comprising a cover member located within a central region of said interior wall, wherein said interior and exterior walls, said venting fuse, and said cover member each comprise unitary portions of a single body.  
     
     
         42 . A fusible bung as defined in  claim 39 , wherein said interior wall includes a threaded bore for receiving a relief valve.