Patent Publication Number: US-6659037-B2

Title: Method and apparatus for the evaluation of vacuum insulation panels

Description:
RELATED APPLICATIONS 
     This is a continuation application that claims priority on U.S. Provisional Application Ser. No. 60/136,039, filed May 26, 1999 entitled “Vacuum Insulation NPanels,” hereby incorporated by reference. In addition, this application claims priority from prior pending U.S. patent application Ser. No. 09/579,816, entitled “Method And Apparatus For The Evaluation of Vacuum Insulation Panels,” filed May 26, 2000, and hereby incorporated herein by reference, now U.S. Pat. No. 6,470,821. 
    
    
     TECHNICAL FIELD 
     The present invention relates, generally, to the evaluation of insulating materials, and more particularly, to vacuum insulation panels, as may be used for various temperature-sensitive products, that are configured to enable the evaluation of the expected performance and integrity of the vacuum insulation panels. 
     BACKGROUND OF THE INVENTION 
     With the rapid world-wide growth in the demand for the shipment and handling of temperature sensitive products, such as blood, food, pharmaceuticals, vaccines, bioengineered products and the like, the need for inexpensive and yet more thermally efficient shipping containers continues to increase dramatically. 
     In designing and manufacturing insulated shipping containers, various factors must be considered, including weight, size and durability. Since many of the products must be shipped at great distances by rail, truck or air travel, the designers of these containers must strive to keep the weight of these containers at a minimum and yet still provide sufficient protection of the goods at the desired temperature for extended periods, e.g., by providing containers with a sufficiently thick layer of insulation. 
     In addition, due to the volume of the goods to be shipped, as well as limitations in available cargo space, the size and configuration of the shipping container must be optimized to maintain the desired temperature and yet minimize the area required for storage. Further, the freight and shipping industry has established pricing regulations, known as dimensional weight regulations, that apply to shipping containers which are larger and yet lighter in shipping weight. For example, it can be generally more expensive to ship containers that have an outside dimension of 24″×24″×24″ and a weight of 40 pounds than it is to ship containers that have an outside dimension of 12″×12″×12″ and a weight of 50 or 60 pounds. Still further, although the minimization of weight and size are desirable design considerations, on the other hand, designers must strive to balance these factors with the need to provide shipping containers that are reusable or can withstand physical impacts or collisions during the shipment of the goods. 
     As a result of these factors, many of today&#39;s shipping containers utilize combinations of inexpensive paperboard boxes and more costly foam insulating materials, such as, for example, polyurethane, polystyrene or the like. Although these materials combine to provide a low-cost insulating container, because these materials typically attempt to trap gases to reduce heat transfer, these materials typically provide a low insulation value, such as R-7 per inch or lower. However, as regulatory agencies continue to enact more stringent regulations for the temperature control of perishable and other temperature-sensitive goods, such as during the transporting or storing of the goods, the need for more reliable and efficient insulating materials continues to grow. As such, the use of vacuum insulation panels (VIP&#39;s) is becoming more and more predominant in industry. 
     Vacuum insulation panels are very efficient in providing insulating protection for temperature-sensitive goods and products. Unlike the traditional insulating materials described above, vacuum insulation materials operate by evacuating or removing the gas molecules that transfer heat within the insulating material. 
     With reference to FIG. 1, a vacuum insulation panel  100  generally comprises a thin, barrier film  102  that is designed to encapsulate a filler core material  106 . Barrier film  102  generally comprises a thin material, such as, a metal foil or metalized film laminate, designed to maintain a vacuum within panel  100 . Meanwhile, core material  106  generally comprises an open-cell material designed to provide a physical structure to panel  100 , to facilitate the drawing of a vacuum from within panel  100 , including vacuum area  104 , and to inhibit the transmission of heat through panel  100 . After drawing the vacuum within panel  100 , barrier film  102  is typically sealed to maintain and hold the vacuum for a prolonged period of time. As a result, vacuum insulation panel  100  can provide approximately three times or more the insulation thermal efficiency, e.g., an R-30 per inch insulation value, than that of traditional products with the same wall thickness. 
     Although these vacuum insulation panels  100  are durable, often lasting two years or more, barrier film  102  is susceptible to deterioration, puncture, tear and other wear that can cause panel  100  to lose the vacuum within barrier film  102  and thus become thermally inefficient for critical temperature applications. Although a detailed visual inspection may lead an evaluator of the panels to a determination as to the integrity of the vacuum within panel  100 , generally only the largely visible punctures or tears may be visible. Accordingly, because various of the defects are not readily detectable, damaged vacuum insulation panels currently have the potential to be reused, and thus the potential exposure to the environment for the temperature-sensitive goods is increased. Thus a strong need exists for a vacuum insulation panel that is configured to facilitate an effective inspection and evaluation of the integrity of the vacuum insulation panel. 
     SUMMARY OF THE INVENTION 
     A vacuum insulation panel according to the present invention addresses many of the shortcomings of the prior art. In accordance with the present invention, a vacuum insulation panel comprises a barrier film and a core material and a vacuum detection indicator. The vacuum detection indicator is configured to facilitate the evaluation of the integrity of the vacuum within the vacuum insulation panel. 
     In accordance with one aspect, the vacuum detection indicator comprises a cavity in the core material which allows the barrier material to form into a depression when a vacuum is drawn within the panel. As the vacuum is reduced or lost, the depression formed in the barrier material will be similarly reduced or lost. 
     In accordance with another aspect, the vacuum detection indicator may comprise a viewing window configured above the barrier material to permit the evaluator to readily determine whether the vacuum has been reduced or lost. 
     In accordance with another aspect, the vacuum detection indicator may comprise a spring-like device configured within the cavity. Upon a reduction in the vacuum with the panel, the spring-like device suitably uncoils to urge the barrier material towards the outer surface of the panel, i.e., the barrier material returns to its original configuration before the vacuum was drawn in the panel. 
     In accordance with yet another aspect, the vacuum detection indicator may also comprise various other features for indicating when the vacuum has been reduced or lost within the panel. In accordance with this aspect, the vacuum detection indicator may comprise of electrical contacts suitably configured to indicate that the barrier material has been returned to its original configuration, e.g., by providing a closed circuit when the barrier material interfaces with the contacts which can be readily measured or utilized. Further, the vacuum detection indicator may comprise a fluid device configured to release colored-dyes upon loss of vacuum, and which can provide a clearly visible indication of the loss of vacuum within the panel. Still further, the vacuum detection indicators may comprise small mechanical devices of even color indicators, for example, devices which in the presence of gasses either show a mechanical (e.g., a bar scale) change or a color change. 
    
    
     BRIEF DESCRIPTION OF DRAWING FIGURES 
     The present invention will be hereinafter described in conjunction with the appended drawing figures, wherein like designations denote like elements, and: 
     FIG. 1 is a cross-sectional, perspective view of a typical vacuum insulation panel; 
     FIG. 2 is a cross-sectional view of a preferred embodiment of a vacuum insulation panel in accordance with the present invention; 
     FIG. 3A is a view of an outer surface of one preferred embodiment of the vacuum insulation panel in FIG. 2; 
     FIG. 3B is a view of an outer surface of another exemplary embodiment of a vacuum insulation panel in accordance with the present invention; 
     FIG. 4 is a cross-sectional view of another exemplary embodiment of a vacuum insulation panel in accordance with the present invention; 
     FIGS. 5A and 5B are cross-sectional views of one type of a vacuum detection system of a vacuum insulation panel in accordance with another embodiment of the present invention; 
     FIGS. 6A and 6B are cross-sectional views of yet another type of a visual detection system of a vacuum insulation panel in accordance with another embodiment of the present invention; 
     FIGS. 7A and 7B are a perspective view and a side view, respectively, of another embodiment of vacuum detection system of a vacuum insulation panel in accordance with the present invention; 
     FIGS. 8A,  8 B and  8 C are a side view, a partial view and a top view, respectively, of yet another embodiment of vacuum detection system of a vacuum insulation panel in accordance with the present invention; 
     FIG. 9 is a side view of yet another embodiment of vacuum detection system of a vacuum insulation panel in accordance with the present invention; 
     FIGS. 10A and 10B are side views of further embodiments of vacuum detection system of a vacuum insulation panel in accordance with the present invention; 
     FIG. 11 is a side view of yet another embodiment of vacuum detection system of a vacuum insulation panel in accordance with the present invention; and 
     FIG. 12 is a side view of an exemplary vacuum detection device as may be utilized in the system of FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS 
     The present invention is described herein in terms of various hardware components and operational steps. It should be appreciated that such components may be realized by any number of devices configured to perform the specified functions. In its various embodiments the present invention may include various types of spring-like mechanisms, tabs, plastics, and the like, which may carry out a variety of functions. However, it should be noted that these devices may be suitably modified, adapted, replace or otherwise exchanged with various other components which can carry out the desired functions. For example, while an insulating core material may comprise foam and the like, it may also comprise any type of open-cell-like material capable of facilitating a vacuum within a vacuum insulated panel. In addition, those skilled in the art will appreciate that the present invention may be practiced in any number of packaging and shipping contexts and that the illustrative embodiment described herein is merely one exemplary application for the invention. For example, the exemplary vacuum insulation panel may be configured in various sizes and configured in various arrangements, such as, small pharmaceutical product packages, or large industrial pallet shipping containers and the like. Still further, it should be noted that the present invention may be suitably practiced within any shipping application in which vacuum insulated panels are utilized For example, the present invention may be utilized not only in the shipping industry, such as for insulated shipping containers, refrigeration trucks or reefers, marine and RV refrigeration and the like, but also for general and specialized refrigeration applications, such as conventional refrigerators and freezers, cold storage units and industrial refrigerators, and vending machines. Such general techniques that may be known to those skilled in the art are not described in detail herein. 
     As discussed above, the deterioration of the vacuum within a vacuum insulation panel leads to a reduction of the thermal efficiency, i.e., the R-value per inch, for the vacuum insulation panel. This is generally a result of the wear and continued use of the vacuum insulation panel which eventually leads to damage to the barrier film, e.g., pin holes, tears or other perforations, or the failure or leaking at the barrier seals, all of which are generally not readily detectable. Accordingly, by providing a determination of whether the vacuum is maintained within the vacuum insulation panel, the integrity and thermal efficiency of the vacuum insulation panel can be evaluated. 
     In accordance with the present invention, it has been discovered that by configuring the core material and/or barrier material in a manner that a vacuum detection device is visually apparent when the vacuum is drawn within the vacuum insulation panel offers significant advantages over the prior art construction. Preferably, in accordance with one aspect of the present invention the detection device is in the form of a cavity suitably configured in the outer surface of the core material such that when a vacuum is drawn within the vacuum insulation panel, the vacuum tends to draw the barrier film into the cavity, e.g., the barrier film forms a depression within the cavity of the core material. Moreover, the depth of the depression of the drawn barrier film within the cavity can be indicative of the strength or viability of the vacuum and thus the thermal efficiency of the vacuum insulation panel. In other words, the greater the relative depth of the depression when compared to the depth of the cavity, the stronger the vacuum, and thus the stronger the insulating thermal efficiency of the vacuum insulation panel. Conversely, the lesser the relative depth of the depression when compared to the depth of the cavity, the weaker the vacuum, and thus the weaker the insulating thermal efficiency of the vacuum insulation panel. 
     In accordance with an exemplary embodiment of this aspect of the present invention, with reference to FIG. 2, a vacuum insulation panel  200  comprises a barrier material  202  and a core material  206 . Barrier material  202  preferably comprises a thin, flexible, film-like material, such as, for example, a metal foil or metalized film laminate, e.g., a metalized polymer or polymeric structure. However, barrier film can also comprise a transparent, non-metallic material, or any combination of metallic and non-metallic materials. Moreover, barrier material  202  is preferably configured to suitably encapsulate core material  206  and facilitate the maintaining of a vacuum within panel  200 . Further, barrier material  202  is readily deformable to provide a vacuum detection indicia  205  within panel  200 , e.g., by providing a depression  212  within a cavity  208  of core material  206 . 
     Preferably, core material  206  comprises an open-cell core material, such as, for example, an open-cell polystyrene or polyurethane foam and the like, suitably configured to facilitate the drawing of vacuum area  204  between barrier material  202  and core material  206 . In accordance with this aspect, core material  206  is preferably configured to provide greater than 95% open-cell, and most preferably approximating 99% or greater open-cell material. Moreover, core material  206  is preferably configured to provide cavity  208  within an outer surface of core material  206 . In accordance with this aspect, core material  206  preferably comprises a substantially rigid material. 
     Cavity  208  may be suitably configured in any location around the outer surface of core material  206 , e.g., suitably configured on the top or bottom surfaces of core material  206 , or along the sides of core material  206 . In accordance with another aspect of the present invention, cavity  208 , and thus depression  212 , can be configured at varying depths within core material  206 . For example, cavity  208  may comprise an indentation within the outer surface of core material  206 . Additionally, cavity  208  may comprise a deep opening within core material  206 , such as, for example, an opening half-way through the body of core material  206  or, an opening all the way through the body of core material  206 . Accordingly, cavity  208  can comprise any depth of an opening within core material  206 . 
     Accordingly, by drawing a vacuum within panel  200 , depression  212  may be created within cavity  208  to suitably provide an indication of whether a vacuum exists within vacuum insulation panel  200 . Stated another way, as long as the vacuum is suitably maintained within vacuum insulation panel  200 , depression  212  may be suitably formed and maintained on panel  200 ; on the other hand, once the vacuum formed within panel  200  begins to be lost, depression  212  will likewise be reduced or no longer maintained on panel  200 . 
     In accordance with one aspect of the present invention, vacuum insulation panel  200  may also comprise a plurality of cavities  208  suitably configured in various arrangements. In accordance with this aspect, vacuum insulation panel  200  may include cavities  208  suitably arranged in various fashions, such as uniformly spaced along the outer surface of core material  206 , as shown in FIG. 3A, or randomly spaced about core material  206 . As such, the plurality of cavities  208  may be suitably oriented in any pattern. 
     In accordance with another aspect of the present invention, cavity  208  may be arranged in any size, shape or orientation. For example, cavity  208  can comprise circular, rectangular or other multiple-sided shapes. Moreover, cavity  208  may be suitably configured in a shape which is representative of other known symbols. Additionally, cavity  208  may be configured as the symbol of an entity, such as a company&#39;s trademark or logo, or in the shape of letters or numbers. 
     For example, in accordance with one aspect of this embodiment and with reference now to FIG. 3B, vacuum insulation panel  200  may include a plurality of cavities  208  configured to represent a particular word, such as, for example, the word GOOD. In other words, since depression  212  will tend be created in a configuration substantially similar to cavity  208  when a satisfactory vacuum has been drawn on vacuum insulation panel  200 , by configuring the plurality of cavities  208  to represent a term whose meaning is indicative of a satisfactory evaluation, e.g., GOOD, OK, GO or the like, an individual can evaluate the thermal efficiency of vacuum insulation panel  200  by inspecting and comprehending a verbal meaning or expression of the term represented by the shapes and configuration of the plurality of cavities  208 . Accordingly, cavity  208  may be suitably configured to aid the evaluator of the condition of vacuum insulation panel  200  in determining and evaluating the thermal efficiency, i.e., the R-value per inch, of vacuum insulation panel  200 . 
     Continuing with this aspect of the present invention, vacuum insulation panel  200  may also comprise a plurality of cavities  208  configured at various depths and sizes within core material  206 . Accordingly, vacuum insulation panel  200  may comprise at least one cavity  208  with a minimal depth and at least one cavity  208  with a larger depth and/or size. For example, with reference to FIG. 4, vacuum insulation panel  200  may be suitably configured to include a plurality of cavities  208  configured at different depths such that a depression  402 ,  404  and  406  are suitably formed within cavities  208 . Accordingly, the varying depths of depressions  402 ,  404 , and  406  can provide an indication of the extent of the vacuum being maintained within vacuum insulation panel  200 . For example, if each depression  402 ,  404 , and  406  are suitably visible to an evaluator of vacuum insulation panels  200 , the evaluator can conclude that the thermal efficiency of panel  200  will be satisfactory, i.e., panel  200  will efficiently perform as intended to insulate the temperature-sensitive goods. Further, in the event that one of the depressions  402 ,  404  or  406  is not visible, for example, a depression having a minimal depth, the evaluator can conclude that the thermal efficiency of panel  200  has deteriorated from its maximum thermal efficiency. Additionally, as more and more depressions  402 ,  404  or  406  become less visible, or not visible at all, the evaluator can conclude that the thermal efficiency and integrity of panel  200  has further deteriorated. Accordingly, the greater the number of depressions  402 ,  404  or  406  that are not visible, the more likely that the deterioration of vacuum insulation panel  200  has increased. 
     Although the above embodiments are configured to facilitate the evaluation of the insulating thermal efficiency of a vacuum insulation panel, it has been discovered that while these arrangements are suitable for many applications, upon deterioration or loss of the vacuum within panel  200 , a readily visible indication of the integrity of the vacuum may not be available. For example, often as a result of the material comprising barrier film  202 , e.g., metal foil or metalized laminate, any deformation developed as a result of the vacuum being drawn within panel  200  may still be partially present even after the vacuum has been reduced or lost, i.e., depression  212  may not return to the original configuration of the respective area of barrier film  202  above cavity  208 , but may instead have a memory of the deformed characteristics. Stated another way, although the deformation of depression  212  will tend to be reduced as the vacuum in panel  200  begins to deteriorate, depression  212  may still retain a portion of the deformation which may lead an evaluator of the integrity of panel  200  to believe or conclude that some of the vacuum in panel  200  is still in effect or being maintained in vacuum area  204 . 
     To better enable vacuum detection indicator  205  to be readily visibly detectable once the vacuum has been reduced or lost, panel  200  may be suitably configured to provide an enhanced vacuum detection indicator upon loss of vacuum. In accordance with this aspect of the present invention, enhanced vacuum detection indicator may comprise any device formed in core material and/or barrier film that enables evaluation of vacuum integrity. In accordance with one aspect of this embodiment, panel  200  may be configured to include a spring-like actuation within cavity  208  such that upon loss of vacuum within panel  200 , the spring-like actuation suitably eliminates any deformation of depression  212  by acting upon depression  212  to substantially return barrier film  202  to its original configuration. 
     In accordance with one aspect, the spring-like actuation may be included within core material  206 . For example, core material  206  may comprise a substantially rigid, open-cell material having spring-like characteristics suitably configured such that cavity  208  will be formed from an inward pressure applied to the outer surface of core material  206 , but will return to a normal configuration, i.e., the original shape of core material  206 , once the pressure is no longer applied. Accordingly, once an inward pressure is applied to the outer surface of core material  206  to create cavity  208 , and a vacuum is drawn on panel  200 , barrier film  202  can facilitate the maintaining of cavity  208  within panel  200  by forming depression  212 . Moreover, once panel  200  loses the vacuum between barrier film  202  and core material  206 , the spring-like characteristics of core material  206  will facilitate the elimination of cavity  208 , and thus deformation  210  of depression  212 . 
     In accordance with another aspect, the spring-like actuation may be included within an additional spring-like device within cavity  208  to substantially return barrier film  202  to its original configuration upon loss of vacuum. Accordingly, the spring-like device may comprise a spring member. Preferably, the spring member is suitably configured to be coiled by barrier film  202  upon the creation of the vacuum within panel  200 , i.e., as the vacuum is created and barrier film  202  is drawn into cavity  208 , the spring member may become coiled into a wound or compressed configuration as a pressure is applied by barrier film  202  onto the spring member. Further, as the vacuum within panel  200  becomes reduced or lost, and the pressure applied by barrier film  202  onto the spring member is correspondingly reduced or eliminated, the spring member may become uncoiled from its wound configuration. As the spring member becomes suitably uncoiled, the uncoiling of the spring member may facilitate the reduction or elimination of deformation  210  of depression  212  by pressing against deformation  210  and towards the outer surface of panel  200 . Accordingly, by the elimination or reduction of deformation  210 , and thus depression  212 , the evaluator can readily determine that the vacuum of panel  200  has been reduced or lost. 
     It should be noted that the above example is merely one exemplary embodiment for carrying out the present invention. However, the present invention is not limited to the above embodiment. Instead, any arrangement, device or feature may be utilized which facilitates the reduction or elimination of deformation  210  of depression  212  by pressing against deformation  210  and urging deformation  210  towards the outer surface of panel  200  to permit an evaluator to readily determine that the vacuum of panel  200  has been reduced or lost. 
     For example, with reference now to FIG. 5, an exemplary vacuum insulation panel  500  may include a barrier film  502 , a core material  506  and a vacuum detection indicator  501  which comprises a spring-like device  512 . Preferably, core material  506  comprises a cavity  504  suitably configured such that barrier material  502  may form a depression  508  within cavity  504  when a vacuum is drawn between within panel  500 . Further, cavity  504  is preferably configured to contain spring-like device  512  such that device  512  can reduce or eliminate depression  508  upon loss of the vacuum in panel  500 . 
     In accordance with this embodiment, spring-like device  512  preferably includes a spring member  514  and a base member  515 . Spring member  514  preferably comprises a spring device that may be coiled or compressed into a retracted position by the force of barrier film  502  upon the creation of the vacuum within panel  500 . Spring member  514  may comprise plastic, rubber, metal or any other material suitable for providing a spring-like actuation. Further, spring member  514  may comprise a single component spring, or may comprise a spring device integrated or otherwise implemented within a compressible tube or other like container device. Base member  515  is suitably attached to spring member  514  and preferably configured to interface with a portion of barrier film  502  when a vacuum is drawn within panel  500 . Base member  515  can be configured in a variety of shapes, thicknesses and sizes. Accordingly, as shown in FIG. 5A, when the vacuum is created within panel  500 , the pressure created by barrier film  502  upon base member  515  can facilitate the compression of spring member  514  into a coiled or compressed configuration, as base member  515  is positioned within cavity  504 . Moreover, with reference to FIG. 5B, in the event the vacuum is subsequently reduced or lost, and spring member  514  becomes uncoiled or decompressed, base member  515  suitably interfaces with barrier film  502  to facilitate a corresponding reduction or elimination of depression  508 , e.g., by pushing barrier film  502  outwards from cavity  504 . Accordingly, by determining the extent of deformation in depression  508 , the evaluator can readily determine that the vacuum of panel  200  has been reduced or lost. 
     Although the above embodiment provides for base member  515  to be positioned within cavity  504 , other variations can be utilized. For example, with reference to FIG. 7, a vacuum insulation panel  700  may include a vacuum detection indicator  701  having a base member  715  configured with a surface area larger than the opening to a cavity  704 , and attached to a spring member  714 . For example, the surface area of base member  715  may comprise a member of one inch to three inches or more in circumference or width. Accordingly, when the vacuum is created within panel  700 , the pressure created by barrier film  702  upon base member  715  can facilitate the compression of spring member  714  into a coiled or compressed configuration, as base member  715  is compressed against the opening of cavity  704 . Accordingly, in the event the vacuum is subsequently reduced or lost, and spring member  714  becomes uncoiled or decompressed, base member  715  suitably interfaces with barrier film  702  to facilitate a corresponding protruding configuration of barrier film  702 , i.e., a protruding portion of barrier film  702  above the normal plane incident to the outer surface of barrier film  702 , that will be readily detectable by an evaluator of the vacuum integrity of the panel. 
     In accordance with another aspect of this embodiment of the present invention, it has been discovered that by configuring a vacuum insulation panel with a viewing window, the evaluator can more readily determine the extent of deformation in a depression of the vacuum insulation panel. In accordance with this embodiment, the viewing window suitably comprises a transparent substrate, such as, for example, plastic, glass or other like materials capable of providing transparent characteristics. Preferably, the viewing window is configured to be placed on or within the outer surface of the vacuum insulation panel to substantially cover the deformation of the depression in the panel. Viewing window may be suitably attached directly to the barrier film surrounding the vacuum insulation panel by any known method for attaching like materials to the barrier film, such as, for example, by adhesion bonding, gluing, welding or fastening and the like. However, the vacuum insulation panel may also be suitably configured such that no part of the viewing window is directly attached to barrier film. Alternatively, the barrier film itself may comprise a transparent and/or non-metallic material. In this manner, a separate viewing window is not necessary, as the film itself would be see-through. 
     In accordance with one aspect of this embodiment, the viewing window is configured such that the portion of the barrier film comprising a depression is not attached to the viewing window to thus permit the depression to deform within the cavity. Accordingly, as the depression is reduced or eliminated as a result of a loss of the vacuum in the panel, the barrier film will suitably interface the viewing window to indicate that the depression has been substantially eliminated. 
     For example, as may be used with vacuum insulation panel  200 , the viewing window may be configured to cover barrier film  202 , preferably covering at least depression  212 . However, viewing window may also suitably cover any other portion of barrier film  202 , possibly even the entire barrier film surrounding core material  206 . Accordingly, the evaluator can more readily determine the extent of deformation  210  in depression  212  of vacuum insulation panel  200 . 
     In cases where a viewing window is provided, conventional gas monitors may be placed in proximity to the viewing window for visible inspection. Such gas monitors may comprise small gauge-like mechanical detectors, paper strip detectors, or the like. As is known, in the presence of certain gasses such detectors change to evidence the gas presence, for example, by changing location of a pointer or a calibrated bar scale or changing color of the strip. In the case where the detector, for example, comprises an oxygen detection strip, it may, for example, be placed inside barrier film  202  in proximity to the viewing window so that if oxygen is permitted to enter panel  200 , the strip will change color and be detected through the viewing window. 
     With reference to FIG. 5A, in accordance with another aspect of this embodiment of the present invention, vacuum detection indicator  501  may further comprise a viewing window  510  suitably configured to cover barrier film  502 , preferably covering depression  508 . In accordance with this embodiment, viewing window  510  suitably comprises a transparent substrate, such as, for example, plastic, glass or other like materials capable of providing transparent characteristics. Preferably, viewing window  510  is suitably attached directly to barrier film  502  by any known method for attaching like materials to barrier film  502 , such as, for example, by adhesion bonding, gluing, welding or fastening and the like. In addition, viewing window  510  is preferably configured such that the portion of barrier film  502  comprising depression  508  is not attached to viewing window to permit depression  508  to deform within cavity  504 , as shown in FIG.  5 A. However, panel  500  may also be suitably configured such that no part of viewing window  510  is directly attached to barrier film  502 . Accordingly, with reference to FIG. 5B, once the vacuum in panel  500  is subsequently reduced or lost, and spring member  514  becomes uncoiled or decompressed, base member  515  suitably interfaces with depression  508  to force a corresponding portion of barrier film  502  towards viewing window  510 . Accordingly, by determining the extent of the deformation in depression  508  through viewing window  510 , the evaluator can determine whether the vacuum of vacuum insulation panel  200  has been reduced or lost. 
     Although the above embodiments are configured to facilitate the visual indication and evaluation of the insulating thermal efficiency of an vacuum insulation panel, in accordance with other exemplary embodiments of the present invention, further features of the present invention for evaluating insulating materials can readily assist the evaluator of the panels. As noted, the above embodiments suitably provide the evaluator with a visual method for determining the extent of the vacuum present in a vacuum insulation panel, by providing for a visual inspection of the amount of deformation of any depressions in the vacuum insulation panel. However, other devices may be employed to indicate that any provided depressions have been reduced, and/or that the vacuum in the panel has been reduced or lost within the various embodiments of the present invention. 
     For example, in accordance with another exemplary embodiment, the vacuum insulation panel comprises a viewing window having at least one pair of electrical contacts suitably arranged within the underside of the viewing window to interface with a portion of the barrier film providing the depression in the panel. Preferably, the electrical contacts are isolated from each other, i.e., there is no electrical continuity between the electrical contacts. Moreover, in accordance with this embodiment, the barrier film includes a contact portion suitably arranged with any such depressions and configured to interface with the electrical contacts of the viewing window once a depression has been substantially reduced or eliminated, i.e., once the vacuum within a vacuum insulation panel has been substantially reduced or lost. Preferably, the contact portion will come into direct contact with the electrical contacts in a manner to provide electrical continuity between the electrical contacts. Accordingly, by providing the evaluator with a device suitable for determining the electrical continuity between the electrical contacts, such as, for example, an ohmmeter, the evaluator can more readily determine that the vacuum within a vacuum insulation panel has been substantially reduced or lost. 
     With reference to FIG. 6A, in accordance with one embodiment, a vacuum insulation panel  600  preferably includes a barrier film  602 , a core material  606 , and a vacuum detection indicator  601  preferably comprising a spring-like device  612  and a viewing window  610 . Preferably, viewing window  610  includes at least one pair of electrical contacts  614  suitably arranged above a portion of barrier film  602  covering a cavity  604 . Further, barrier film  602  preferably includes a contact portion  616  configured to interface, and thus provide electrical continuity between, electrical contacts  614 . 
     Electrical contacts  614  can comprise any conductive alloys suitably configured to provide electrical conductivity, such as, for example, copper, aluminum, tin or the like. Moreover, electrical contacts  614  can be configured in virtually any shape, such as, for example, circular, rectangular or any other known shape, to facilitate the interfacing with a measuring device, such as, for example, an ohmmeter, suitable for determining the electrical continuity between electrical contacts  614 . In accordance with this aspect, electrical contacts  614  preferably provide access to the measuring device by providing an outer surface suitable for interfacing with the measuring device, and may be configured to protrude above viewing window  610 . Preferably, electrical contacts  614  are configured within viewing window  610  such that electrical contacts  614  may come into direct contact with contact portion  616 . In accordance with this aspect, electrical contacts  614  preferably protrude from beneath viewing window  610 . Although viewing window  610  preferably includes at least one pair of electrical contacts  614 , viewing window may also include three, four or even more additional electrical contacts  614  suitably arranged above barrier film  602  approximate cavity  604 , i.e., around the portion of barrier film  602  configured to provide a depression once a vacuum is drawn in between barrier film  602  and core material  606 . 
     In accordance with another aspect, and with reference now to FIG. 6B, viewing window  610  may also comprise electrical conductive strips  618  suitably connected to electrical contacts  614  to provide a greater surface area to interface with the measuring device for determining the electrical continuity between electrical contacts  614 . In accordance with this aspect, conductive strips  618  may comprise any conductive alloy suitably configured to provide electrical conductivity. Moreover, conductive strips  618  can be configured in any shape suitable for interfacing with the measuring device. Although conductive strips  618  are preferably configured onto an outer surface of viewing window  610 , conductive strips  618  may also be configured within an interior as well as the outer surface of viewing window  610 . Further, conductive strips  618  may be suitably configured to permit electrical contacts  614  to not be exposed directly to the outer surface of viewing window  610 , and thus to the measuring device, but rather allow the electrical continuity between electrical contacts  614  to be determined solely by measuring electrical continuity between conductive strips  618 . 
     Contact portion  616  preferably comprises any conductive alloy suitably configured to provide electrical conductivity, such as, for example, copper, aluminum, tin or the like. Moreover, contact portion  616  can be configured in virtually any shape, such as, for example, circular, rectangular or any other known shape, suitable for interfacing with, and providing electrical continuity between, electrical contacts  614 . In accordance with this aspect, contact portion  616  is preferably configured above a portion of barrier film  602  capable of being deformed within cavity  604 , i.e., a depression  605  of barrier film  602 . 
     Accordingly, as a vacuum in panel  600  becomes subsequently reduced or lost, and spring-like device  612  becomes uncoiled or decompressed, spring-like device  612  suitably interfaces with depression  605  to force a corresponding portion of barrier film  502 , and thus contact portion  616 , towards electrical contacts  614 . Once the vacuum in panel  600  has been substantially reduced, contact portion  616  preferably interfaces with, and provides electrical continuity between, electrical contacts  614 . Accordingly, by providing the evaluator with a device suitable for determining the electrical continuity between the electrical contacts, such as, for example, an ohmmeter, the evaluator can more readily determine that the vacuum within vacuum insulation panel  600  has been substantially reduced or lost. 
     While the above embodiment illustrated in vacuum insulation panel  600  is configured to provide another positive indicator that the vacuum within an insulation panel has been substantially reduced or lost, various other embodiments may be configured for providing an evaluator with the ability to readily determine the integrity of the vacuum within a vacuum insulation panel. For example, the vacuum detection indicator may also comprise a fluid device, such as a membrane or a plunger-like component, containing colored dyes and configured beneath a viewing window such that upon loss of vacuum, the fluid device may be configured to deliver the colored dyes unto the underside of the viewing window. Further, the actuation of the fluid device may be enabled by a spring-like member as discussed above, or may be a result of the barrier film returning to its original configuration upon loss of the vacuum. Thus an evaluator can determine whether a vacuum has been lost by observing the viewing window to determine whether the colored dyes have been released by the fluid device. 
     With reference to FIG. 8A, an exemplary vacuum insulation panel  800  suitably includes a barrier film  802 , a core material  806 , and a vacuum detection indicator  801  having a spring member  814  and base member  815 , as described above. However, in addition to the above elements, vacuum insulation panel  800  also includes a fluid device  830  configured to contain a colored dye that may be delivered, dispensed or otherwise ejected from fluid device  830  to indicate the loss of the vacuum within panel  800 . Fluid device  830  suitably comprises a membrane, a bag or other like component capable of containing colored dyes within in the absence of pressure exerted onto the outer surface, and to deliver, dispense or otherwise eject the colored dyes upon the exertion of a compression force onto the outer surface of the membrane or bag. 
     Although fluid device  830  can comprise a membrane, bag or other like component capable of containing colored dyes, the present embodiment is not limited to such a component. For example, fluid device  830  may also be configured as a plunger-like device, for example, a plunger and syringe device, such that pressure exerted by the plunger may force colored dyes within the syringe device to be forced through an orifice and into cavity  804 , and thus be readily detected. Accordingly, fluid device  830  may comprise any component configured for containing colored dyes and dispensing the same upon application of a compression force. 
     In addition, fluid device  830  is preferably configured between base member  814  and a transparent portion of barrier film  802 , e.g., a viewing window, such as is illustrated in FIG.  8 B. The viewing window may comprise a transparent plastic or other similar component suitably attached to barrier film in various known manners, such as by adhesive bonding, gluing or any other available means for attaching a component to a barrier film. Further, the viewing window may comprise a flexible material that may be readily deformed, or may comprise more rigid material compositions. Moreover, the viewing window is suitably configured such that fluid device  830  is readily visible by the evaluator of the panels, as illustrated, for example, in FIG.  8 C. 
     In addition to the above elements, a protective cover  810  may also be configured around a portion of panel  800 , for example, to substantially cover vacuum detection indicator  801 , or at least cover a portion of the viewing window of barrier film  802 . Further, cover  810  suitably comprises a transparent material, or at least includes a transparent portion, configured adjacent the viewing window such that fluid device  830 , or any delivered, dispensed or otherwise ejected colored dye is readily visible by the evaluator of the panels. 
     Accordingly, upon the initial maintenance of a vacuum within panel  800 , barrier film,  802  will be drawn into a cavity  804 , thus compressing fluid device  830  and spring member  814 . However, in the event the vacuum within panel  800  is reduced, the pressure exerted by spring member  814  will force fluid device  830  outwards from cavity  804  and against the viewing window and cover  810 . Once the vacuum is lost, spring member  814  is suitably configured to provide a compression force against fluid device  830  such that any colored dyes contained within fluid device  830  can be suitably dispensed or ejected, such as through finite orifices within fluid device  830 , or through rupture of fluid device  830 , and within cavity  804 . Accordingly, through the viewing window and cover  810 , any such dispensed dyes may be readily detected by the evaluator to indicate a loss of vacuum within panel  800 . 
     While the above exemplary application illustrates a fluid device  830  configured between a base member  815  and a barrier film  802 , the present invention is not limited to such a structure and may be configured in various other manners and arrangements that are adapted to provide a readily detectable indication that the vacuum has been substantially reduced or eliminated within the vacuum insulation panel. For example, fluid device  830  may be configured between barrier film  802  and cover  810 . In addition, with reference to FIGS. 10A and 10B, fluid device  830  may also be configured within a raised portion  812  of cover  810 , and attached or otherwise connected to the underside of raised portion  812 . Raised portion  812  suitably comprises a housing configured to contain fluid device  830 , and configured to permit base member  815  to enter into raised portion  812  and thus come into contact with fluid device  830 . Further, raised portion  812  preferably includes a substantially transparent feature to permit an evaluator to visibly detect or observe the presence of fluid device  830 , as described above. Moreover, in that fluid device  830  is suitably positioned adjacent cover  810 , a viewing window may not be provided within barrier film  802 . Accordingly, when a vacuum is being maintained within panel  800 , barrier film  802  compresses spring member  814 . However, once the vacuum is lost, the decompression of spring member  814  forces base member  814  and thus barrier film  802  against fluid device  830  to thereby dispense or otherwise eject the colored dyes within panel  800 , such that an evaluator may readily detect the presence of colored dyes through the transparent features of raised portion  812 . 
     As discussed above, fluid device  830  may be configured between cover  810  and base member  815  in various manners to provide the intended functions for indicating loss of vacuum. In addition to the positional arrangements described above, fluid device  830  may be configured to dispense, deliver or otherwise eject any colored dyes contained within at the direction of any number of varying compression forces applied to an outer surface of device  830 . Meanwhile, spring member  814  may be configured with various tension settings, depending on any number of design criteria, to allow spring member  814  to suitably contract and expand. These tension design criteria can be realized in any number of ways to control the spring tension within a small variance, e.g., within a few torr of the desired tension setting, such as through the selection of various alloys, plastics and the like, or the thickness of the spring member, as well as other conventional factors for obtaining desired tension settings in spring members. 
     In addition to the above methods for controlling spring tension, additional spring members  814  may be suitably included within vacuum detection indicator  801 , for example, a series of spring members  814  stacked beneath barrier film  802  and core material  804 . Further, such additional spring members  814  may be suitably included between barrier film  802  and cover  810  to provide additional tension control. With reference to FIG. 9, for example, additional spring member  814   b  may be attached or otherwise coupled to fluid device  830  and adjacent the outer surface of barrier film  802 . Preferably, spring members  814   a  and  814   b  are configured with opposing compression forces such that the spring tension for spring member  814   a  is sufficiently greater than the spring tension of spring member  814   b . Accordingly, as a vacuum is maintained within panel, and barrier film  802  is drawn into cavity  804 , spring member  814   a  will be compressed by barrier film  802  and the opposing spring tension of spring member  814   b . However, once the vacuum has been substantially reduced or eliminated, spring member  814   a  will suitably expand to force spring member  814   b  into compression and to apply a like force onto the outer surface of fluid device  830 , thus causing the discharging or otherwise dispensing of colored dye from device  830 . 
     While spring members  814  can be effectively utilized to apply a compression force against fluid device  830  in numerous manners, such as those described above, still other variations are applicable. In accordance with another embodiment, a vacuum detection indicator may include additional elements or steps to facilitate the discharging or dispensing of colored dyes. For example, rather than have the colored dyes dispensed by fluid device  830  subsequent to a loss of pressure, the colored dyes may be discharged by fluid device  830  into a reservoir that contains the colored dye upon the initiation of a vacuum within the panel, and releases the colored dyes upon loss of the vacuum. With reference to FIGS. 11 and 12, one such exemplary embodiment is illustrated. 
     In this embodiment, a vacuum insulation panel  1100  comprises a vacuum detection indicator comprising a reservoir  1200  having at least one container seal  1206 , at least one spring member  814 , a fluid device  830 , and at least one puncture device  1202 . Container seal  1206  is configured to suitably contain colored dyes within reservoir  1200  once discharged from fluid device  830 . Meanwhile, puncture device  1202  is suitably configured to puncture fluid device  830 , such as a membrane and the like, to discharge colored dyes into reservoir  1200 . Spring member  814  is suitably configured to maintain an opening of container seals  1206  in the absence of a sufficient force applied by barrier film  802  applied to the outer surface of reservoir  1200 . 
     During operation, once a vacuum is developed within panel  1100 , the subsequent drawing of barrier film  802  into cavity  804  will provide a compression force to reservoir  1200 , and thus spring member  814 , to suitably puncture fluid device  830 , as well as close container seal  1206 . However, upon loss of vacuum, colored dyes present within reservoir  1200  can be discharged through container seals  1206  as spring member  814  exerts an expansion force against the inner walls of reservoir  1200 . Accordingly, an evaluator can readily detect the presence of colored dye through the available viewing portion of cover  810 , and thus conclude that the vacuum has been lost within panel  1100 . 
     Alternatively, as briefly noted hereinabove, reservoir  1200  may suitably comprise a gas indicator of a chemical or mechanical configuration. Upon the detection of a desired gas, for example, air, indicator may change (for example, change color), which change can be viewed through viewing window  810 . Alternatively, barrier film  802  may comprise an entirely transparent material. 
     The present invention has been described above with reference to various preferred embodiments. However, those skilled in the art will recognize that changes and modifications may be made to the various exemplary embodiments without departing from the scope of the present invention. For example, rather than providing a conductive contact portion onto the barrier film, the barrier film may be suitably configured to be a highly conductive strip that can provide electrical continuity between the electrical contacts of the viewing window. In addition, various other configurations and arrangements of the spring members, fluid devices and viewing windows, now known or hereinafter devised, can be utilized to provide a readily detectable indicator of a loss of vacuum, and such other additional configurations are not described herein. For example, the base members may be directly configured within the barrier films, or separately attached by various methods. In addition, multiple fluid devices may be utilized with a unity vacuum detection indicator, for example, beneath and/or above the barrier film. Accordingly, these and other changes or modifications are intended to be included within the scope of the present invention.