Patent Publication Number: US-2020286407-A1

Title: Selectively Visible Product Marking System

Description:
FIELD OF THE INVENTION 
     This invention is directed to a system for displaying desired and/or required product markings without diminishing or detracting from the appearance of the product. 
     BACKGROUND OF THE INVENTION 
     Sometimes, it is necessary to mark products with informational or certification markings. As one non-limiting example, Underwriters Laboratories has very specific marking requirements for various products which, first, must meet UL&#39;s strict standards. In many instances, however, the required markings can detract significantly from the appearance of the marked products. 
     Accordingly, there is a need for a marking system which complies with various requirements for marking products without making the products themselves unnecessarily unsightly. 
     SUMMARY OF THE INVENTION 
     The instant invention provides a system with which one may mark products to indicate compliance with the requirements of various agencies and organizations such as UL. According to the invention, markings are applied to products with indicia that is selectively visible. One example is indicia formed with an ink that is visible only outside of the visible light spectrum. Various agencies and certifying bodies, for example, can discern the markings at any time by rendering the markings visible. Visibility can be achieved, for example, by exposing the marking to ultraviolet light so that one may perceive the marking. When the light is extinguished, the markings are no longer perceptible. Thus, the system affords an agency or certifying body the ability to confirm that products are properly marked and, once this has been confirmed, the UV light, in this example, is extinguished and one who encounters the marked product will not perceive the markings on the marked product. 
     Accordingly, it is an object of the invention to provide a product marking system in which products are marked with indicia which is selectively visible. For example, an ink that is not visible to the human eye under the standard visible light spectrum, can be made visible for inspection and product approval purposes by employing plug-in or portable lighting sources that renders the product labeling perceptible. 
     It is another object of the invention to provide a product marking system that allows persons, such as for example, building inspectors to selectively render visible markings on components of an HVAC system, for example, to confirm that the product markings comply with an agency&#39;s requirements for component approvals and markings so that one who views those components, when they are not being inspected, does not perceive the markings. 
     It is a still further object of the invention to provide a marking system which meets various requirements for labeling and marking products yet does so in a way that the appearance of the product when in use is pleasing and uncluttered with information that is not needed by those who are not involved in inspecting or certifying the products. 
     These and other objects of the invention will be apparent from the following description of non-limiting examples of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  is a perspective view of a section of an HVAC duct with a seam covered by a selectively visible product marking system. 
         FIG. 2  is a perspective view of the HVAC duct section shown in  FIG. 1  where markings on the selectively visible product marking system have been selectively rendered visible. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     A section of an HVAC duct, indicated generally at  10  in  FIGS. 1 and 2 , has a longitudinal seam  11  that is covered by a flexible and selectively visible product marking system (hereafter “marking system”)  12 . In HVAC parlance, the marking system  12  constitutes an HVAC duct closure and it is subject to marking/labelling requirements. Underwriters Laboratories has promulgated marking requirements for duct closures. The UL requirements provide that HVAC duct closures, such as tape or laminates used to seal ducts, must include a visible certification marking on every six square inches of the surface. Inspectors look for these markings and they must be visible in order to pass or approve a system after it&#39;s installed. However, such markings can be unsightly, and they only need to be seen by inspectors. 
     According to the marking system of the invention, certification marks, for example, are printed on and/or applied to the duct closure component of an HVAC installation. This is typically done before the components are assembled. The UL marking requirements are stringent. For example, UL181A governs the markings that must be applied to HVAC duct closure tape on Class 1 ductwork. UL181A requires that closure tape have a separate certification mark on every six square inches of exposed area. According to the invention, the certification mark and/or other required indicia is applied to the duct closure with an ink that is selectively visible and not discernable except outside of the visible spectrum of light. Examples of such inks include ultra-violet ink and infrared ink. Suitable inks may be those containing silver nitrate because they are selectively visible, and they do not suffer from sensitivity to heat. When exposed to a suitable light source such as an ultra-violet light source, inks containing silver nitrate are visible, and they are not discernable when the ultra-violet light source is removed. 
     In  FIG. 1 , the marking system  12  includes a base material  13  and indicia  20  formed on the base material  13 . In the illustrated embodiment, the base material  13  is formed from HVAC compatible duct closure components, such as the non-limiting example of an adhesive backed, woven fabric, to provide strength. The threads or fill yarn of the fabric may be cotton, polyester, nylon, rayon or fiberglass. The fabric is a very thin gauze called “scrim” which is laminated to a backing of low-density polyethylene. However, in other embodiments, the base material  13  can be formed from other suitable materials. A visible top surface  22  of the base material  13  is printed with a selectively visible indicia  20 . In  FIG. 1 , the selectively visible indicia  20  is not visible under the visible light spectrum. A light source  14  in  FIG. 2  is shining on the marking system  12  with the result that the indicia  20  on the marking system, shown in  FIG. 2 , is visible. 
     Foils that can be applied to duct closures are well suited for the marking system of the invention. These materials must be marked with a suitable ink that is at least selectively visible. Inks, such as those described above, are selectively visible so that they serve the required marking function and do not degrade the aesthetics of the marked product. If desired, a poly coating may be overlaid on the printed foil to provide better performance and to prevent the ink from being disturbed. 
     While the marking system illustrated in  FIGS. 1 and 2  is described above in the context of a duct closure component, it should be appreciated that the marking system can be used in other circumstances requiring selective viewing of markings. Non-limiting examples of other suitable uses of the marking system include emergency applications, medical applications, industrial machinery applications and the like. 
     It will be appreciated that the foregoing description of an example of the invention is provided only to enable one skilled in the art to practice and carry out the invention and should in no way be considered to be limiting so far as the scope of the invention is concerned.