Abstract:
The present invention generally provides for an apparatus and method for heat shrinking an envelope of heat shrinkable sleeving material into circumferential and longitudinal conformity with a substrate product enclosed by the sleeving material. The present invention provides for a sleeve gripping/holding tool and sleeving table apparatus combination used during the heat shrinking method of the invention for enabling the tensioning and positioning of a heat shrinkable sleeve during the heat application process.

Description:
FIELD OF INVENTION  
       [0001]     The present invention relates generally to methods for heat-shrinking an enclosure of protective fluoropolymer shrinkable material into conformity over an ultraviolet (UV) lamp or quartz tubing for use in various applications. Furthermore, the present invention also relates to tools for holding and tensioning heat shrinkable sleeve material.  
       BACKGROUND OF THE INVENTION  
       [0002]     UV lamps are used in various applications to sterilize products and fluids, among other things. Protective sleeves are needed for the lamps to prevent contamination of the products and fluids.  
         [0003]     Heat shrinkable materials such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), perfluoromethylvinylether (MFA) co-polymer, and tetrafluoroethylene hexafluoropropylene vinylidene fluoride (THV) have gained substantial acceptance in the industry for protective sleeves for lamps, including UV lamps.  
         [0004]     Methods of covering UV lamps are shown in U.S. Pat. No. 6,741,024 B2 to Burgess, et al., U.S. Pat. No. 3,753,036 to Roche, U.S. Pat. No. 4,449,071 to Yokoyama, U.S. Pat. No. 6,043,600 to Sica and U.S. Pat. No. 6,452,325 B1 to Dupont.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     Many of the aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention.  
         [0006]      FIG. 1  is a cross-section view of a vessel employing sleeved lamps for decontamination;  
         [0007]      FIG. 2  is a side view of a conveyor system employing sleeved lamps for decontamination;  
         [0008]      FIG. 3  is a partial end cross-section view of a sleeved lamp showing coverage of lamp end components;  
         [0009]      FIG. 4  is a graph showing percent transmission of ultraviolet light through various sleeving materials used in the invention;  
         [0010]      FIG. 5  is a cross section view of a sleeved lamp showing open lamp end components;  
         [0011]      FIG. 6  is a partial central cross-section view of a sleeved lamp;  
         [0012]      FIG. 7  is an isometric view of the preferred embodiment of the invention;  
         [0013]      FIG. 8  is an isometric view of an alternate embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     The present invention provides both an apparatus and method for manufacturing of sleeved lamps.  
         [0015]     A heat shrinkable sleeve is placed as a protective barrier over the UV lamp in either application, so that it lies between the UV lamp and the fluid stream or product. The heat shrinkable sleeve significantly reduces particulate fouling. The sleeve encapsulates the lamp so that, in the event of damage or breakage of the lamp, the contents of the lamp and the pieces of the tube remain encapsulated within the sleeve.  
         [0016]     For example,  FIG. 1  depicts an illustrative side view of a decontamination vessel  1 . Vessel  1  is generally constructed in a cylindrical in shape and includes inlet  10  and outlet  15  connections. In use, liquid or gas flowing through vessel  1  are decontaminated by UV lamps  20  enclosed within vessel  1 . The UV lamps contained within vessel  1  are sleeved with a protective material utilizing the apparatus and method of the present invention.  
         [0017]     For example,  FIG. 2  depicts an illustrative side view of a decontamination process for products. The decontamination process comprises a conveyor system  22  on which a product  21  is carried. Product  21  is transported by conveyor system  22  under UV lamp  20  within a distance  23  so as to provide sufficient radiation to decontaminate product  21 . In this application, UV lamp  20  must be sleeved with a transparent or translucent sleeve.  
         [0018]     For example,  FIG. 6  shows a cross sectional view of UV lamp  20  within quartz tube  25  having heat shrinkable sleeve  75  applied. Inner wall  62  of quartz tube  25  is separated from UV lamp  20  by air space  80 . The method provides that “twists” and air pockets between the sleeve and the tube be eliminated.  
         [0019]      FIG. 3  illustrates a preferred technique for mounting a sleeved protective quartz tube  25  in vessel  1 . End fitting  40  covers the end of vessel  1  and has overlapping flange  35  which provides a fluid tight seal. End fitting  40  is typically bolted to vessel  1 . End fitting  40  is preferably made from aluminum, steel or similar material. At the proper location for each UV lamp  20 , quartz tube  25  extends through fitting  40 . UV lamp  20  is contained within quartz tube  25 . Jam nut  45  is threaded into end fitting  40 . O-rings  50   a  and  50   b  are used to seal around quartz tube  25  and may include additional washers and sealing devices (not shown) as appropriate. Quartz tube  25  and lamp end  55 , encased by heat shrinkable sleeve  75 , extends into jam nut  45 . Electrical connecting pins  60   a  and  60   b  extend from lamp end  55  of UV lamp  20  and are used to connect a power source to UV lamp  20 .  
         [0020]     In another embodiment,  FIG. 5  depicts a cross-sectional view of heat shrinkable sleeve  75  covering UV lamp  20 . In this embodiment, heat shrinkable sleeve  75  is applied directly to UV lamp  20  as opposed to the quartz tube. Also, the sleeve does not extend over lamp end  55 .  
         [0021]     In a preferred form, heat shrinkable sleeve  75  is made in a hollow flexible cylinder supplied in different lengths with circumferential dimensions close to those of UV lamp  20  or quartz tube  25 .  
         [0022]     The dimensions of heat shrinkable sleeve  75  chosen in the preferred embodiment depend on the UV lamp to be covered. In each instance, the inside diameter of the sleeve before shrinking should be at least 2% larger than the outside diameter of the lamp to be covered. The linear dimension of the shrinkable sleeve before shrinking should be approximately 20% longer than the UV lamp to be covered. In a preferred embodiment, the linear dimension of the sleeve is approximately 4 inches longer than the UV lamp to be covered.  
         [0023]     Thicknesses of the material used for the sleeve can range from about 0.01 inches to about 0.1 inches with a preferred range of between 0.02 inches and 0.06 inches. Tolerances of plus or minus 20% are acceptable.  
         [0024]     The recovered diameter of heat shrinkable sleeve  75  after heat shrinking should be less than outer diameter of UV lamp  20 , quartz tube  25  or other object to be covered to allow for a secure fit. In the preferred embodiment, the recovered diameter should be no less than 2% smaller than the object to be covered.  
         [0025]     In another preferred embodiment, heat shrinkable sleeve  75 , while hollow and cylindrical is supplied flat on a roll. The roll is generally disk shaped and is supported on a spool and spindle attached to the table (not shown). In this embodiment, a length of heat shrinkable sleeve  75  is dispensed according to the required dimensions of the tube. In the preferred embodiment, the length of the sleeve should be between 2 inches and 20 inches longer than the tube to be covered.  
         [0026]     Heat shrinkable sleeve  75  in the preferred embodiment is chosen from a range of materials such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), perfluoromethylvinylether (MFA) co-polymer, and tetrafluoroethylene hexafluoropropylene vinylidene fluoride (THV). Transparent or translucent materials with high UV transmission percentages are preferred. A known approximate transmission percentage of ultraviolet light through various thicknesses of various materials which can be used in the invention are set out in  FIG. 4  for reference.  
         [0027]     Other transparent or translucent materials with high UV transmission rates are acceptable, and therefore are preferable in many circumstances.  
         [0028]      FIG. 7  shows a sleeving table  90  according to the present invention. Work surface top  105  of sleeving table  90  is mounted to work surface frame  180  and has a width of about 12½ inches, a height above the floor surface of about 36 inches, and a length of about 98 inches. Top  105  is preferably made from a light yet rigid material such as a metallic material. Work surface frame  180  is made of aluminum channel. Of course, other materials will suffice if they provide sufficient rigidity. Top  105  is supported in a generally horizontal position by vertical support legs  110   a,    110   b,  and  110   c.  In the preferred embodiment, the legs have a height of about 36 inches. Vertical support legs  110   a,    110   b,  and  110   c  can be folded underneath work surface frame  180  into a transport/storage position for transport or storage by locking hinges, thereby permitting easy movement to and from different locations.  
         [0029]     Clamps  95   a  and  95   b  are provided to grip the sleeving material. The clamps are made of metallic materials such as steel or aluminum for durability, resiliency, and strength. The clamps exert a grip strength sufficient to hold heat shrinkable sleeve  75  when a tension force is applied to tensioning cable  115 .  
         [0030]     Clamp  95   a  is mounted to tensioning cable  115  in the preferred embodiment via a standard U-bolt cable clamp (not shown). Clamp  95   a  in the preferred embodiment is comprised of two hinged jaws  96  and  97 . Hinged jaws  96  and  97  each are provided with a gripping surface  98  and  99 . Each gripping surface can be serrated or made from a material with a high coefficient of friction such as rubber or sandpaper. The jaws are maintained in a closed position by tension spring  107 . Tension spring  107  provides adequate tension to hold heat shrinkable sleeve  75  when a tension force is applied to tensioning cable  115 . In another embodiment, clamp  95   a  can be attached to tensioning cable  115  through a coupling (not shown) capable of rotation about the axis of the cable.  
         [0031]     Clamp  95   b  is mounted to sleeving table end  150   a  on work surface top  105 . In one preferred embodiment, clamp  95   b  is rigidly attached to work surface top  105  by a process such as welding. Other means of rigid attachment such as bolting the clamp to the table is also possible and acceptable. Clamp  95   b  is constructed from resilient plates  101  and  102 . The resilient plates of the preferred embodiment are fabricated from aluminum channel stock. Of course, other stiff resilient materials will work as well. The plates are provided with rubber surfaces (not shown) on each inside surface which contact the sleeve during use. The plates are attached through hinge  103  and cooperating pressure nut  105  and screw  104 . In operation, pressure nut  105  and screw  104  are advanced, creating pressure between plates  101  and  102  to hold the sleeve.  
         [0032]      FIG. 8  shows a second preferred embodiment of clamp  95   b.  In this preferred embodiment, clamp  801  is connected to table  810  through the cooperation of shaft  815 , retaining nut  805  and plate  820 . Plate  820  is provided with hole  825  of sufficient diameter to allow the passage and rotation of shaft  815 . Retaining nut  805  is fixed to shaft  815  and is provided with a diameter larger than hole  825 . During use, this embodiment allows the rotation of clamp  801  about the axis of shaft  815  as shown by arrow  830 . The clamp and plate in the preferred embodiment are dimensioned to allow complete rotation of the clamp.  
         [0033]     Clamp  801  is constructed from resilient plates  836  and  837 . The resilient plates of the preferred embodiment are fabricated from aluminum channel stock. Of course, other resilient materials will work as well. The plates are provided with rubber jaws (not shown) on each inside surface which contact the sleeve during use. The plates are attached through hinge  840  and cooperating pressure nut and screw  835 . In operation, pressure nut and screw  835  are advanced, creating pressure between plates  836  and  837  to hold the sleeve. In the preferred embodiment, shaft  815  is rigidly connected to either plate  836  or  837 .  
         [0034]     Returning to  FIG. 7 , winch  121  is rigidly mounted to the bottom of the sleeving table with supports  122  and  123 . The supports are rigid and provide adequate support to prevent movement of the winch during operation. Tensioning cable  115  is connected to the spool (not shown) of winch  121 . Handle  160  is used to operate the winch to apply tension to tensioning cable  115 . Winch  121  is fitted with a ratchet and pawl assembly having a release (not shown). The release has two positions. In the first position, tension can be maintained on tensioning cable  115  without a force being applied to handle  160 . In the second position, a continual force must be applied to handle  160  to maintain tension, but the tension can be varied.  
         [0035]     Tensioning cable  115  in an alternative embodiment can be a flat rubber belt or belt of other material which expands little under tension loads. In another preferred embodiment, the belt can be notched or marked in order to index the distance that the belt moves and/or the linear expansion of the sleeve.  
         [0036]     An electric motor and gearbox and controller can be substituted for winch  121  in a preferred embodiment. In either case, the tension force applied in tensioning cable  115  is about 5 to 50 lbs., depending on the material used for the heat shrinkable sleeve. In one preferred embodiment, a variable tension is applied to control nonlinear shrinkage or to vary the final thickness of the sleeve.  
         [0037]     A pulley (not shown) is rigidly suspended from the table near end  150   b  and serves as a block to redirect the cable vertically. A rotatable rod  130  is provided to redirect the cable back toward sleeving table end  150   a.  In the preferred embodiment, the rod has a diameter of about and inch. Rod  130  is rotatably mounted between supports  145   a  and  145   b  in bearing blocks  146   a  and  146   b  at a height of about 11 inches as measured from work surface top  105 . The pulley and rotatable rod cooperate to redirect the tension and reverse the direction of the tension force by about 180 degrees. Depending on the lamp used, the angle of redirection can be grater than 180 degrees.  
         [0038]     The winch, in combination with the cable, pulleys and a rotatable rod are utilized to exert tensioning forces on heat shrinkable sleeve  75 . The physical positions of the winch, handle, pulley, rod and clamps in relation to the table allow the process of the invention to be carried out by a single person if need be.  
         [0039]     The method of the present invention is conducted in the following manner. The material for heat shrinkable sleeve  75  is selected based on the desired percentage of transmission of UV light, the final dimensions after heating, the diameter before heating, the diameter of the UV lamp and on the extent of linear coverage desired. The diameter of the sleeve must accommodate the diameter of the UV lamp before shrinking but cannot be so large as to prevent an air tight fit after shrinking to the recovered diameter. The UV lamp is then placed in the sleeve. The sleeve should overlap the ends of the UV lamp by the proscribed amount.  
         [0040]     Clamps  95   a  and  95   b  are then affixed onto the overlapping ends of heat shrinkable sleeve  75 . Tension is applied by winch  121 . In one embodiment, the tension force is adjusted and maintained constant to provide uniform radial contraction of the sleeve and to prevent axial contraction of the sleeve. In another embodiment, a variable tension is applied by the winch to adjust for the nonlinear rate of shrinkage or expansion of the sleeve during the process.  
         [0041]     Heat is then evenly applied with a suitable heat source over the length and outer diameter of heat shrinkable sleeve  75  until heat shrinkable sleeve  75  is evenly and consistently applied to the surface of the UV lamp. In one embodiment, the heat source is a heat gun having a voltage and wattage rating of about 120 VAC and about 1200 W with a range of 100 to 150 watts, and a temperature capability from about 250 to about 1100 degrees Fahrenheit. The heat gun may be manually used to supply even heating of the sleeve or may be mounted to the table for ease of use. In another alternate embodiment, a convection oven can be used to apply the required heat. In yet another embodiment, radiant energy sources such as infrared lights can be used.  
         [0042]     In one embodiment, the UV lamp is periodically rotated during the process while simultaneously applying heat to provide uniform shrinkage and to help prevent air bubbles between heat shrinkable sleeve  75  and the lamp.  
         [0043]     Application of the combination of hot air and positional tensioning causes heat shrinkable sleeve  75  to shrink into an airtight fit with the configuration of the lamp, lamp end  55  and electrical connecting pins  60   a  and  60   b,  as desired.  
         [0044]     After sufficient cooling, the excess sleeve material is removed from the UV lamp. The process is complete when the UV lamp is firmly sealed with heat shrinkable sleeve  75 .  
         [0045]     It should be understood that the present apparatus and method disclosed herein is not limited to use with and application to UV lamps or quartz tubes. The disclosed sleeving table apparatus and method for application of such sleeving can be used for application of heat shrinkable sleeving to any substrate product desired.  
         [0046]     It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention.  
         [0047]     This invention is susceptible to considerable variation in its practice. Accordingly, this invention is not limited to the specific exemplifications set forth herein above. Rather, this invention is within the spirit and scope of the appended claims, including the equivalents thereof available as a matter of law.  
         [0048]     The patentees do not intend to dedicate any disclosed embodiments to the public, and to the extent any disclosed modifications or alterations may not literally fall within the scope of the claims, they are considered to be part of the invention under the doctrine of equivalents.