Abstract:
A foam drying apparatus is provided. The apparatus is configured to pass air, and in some cases heated and/or dried air, through a quantity of foam. This air passing through the foam absorbs or otherwise carries moisture out of the foam, drying it. The apparatus may utilize a pressure differential on opposite sides of the foam, causing air on the higher pressure side to pass through the foam. Typical applications may include the drying of foam assemblies which use water based adhesives to accelerate drying of the adhesive and/or removal of water from the foam assembly, and packaging of the foam assembly.

Description:
BACKGROUND 
       [0001]    In foam assembly processes, such as foam mattress assembly, water based adhesives provide a safe, effective, and non-hazardous solution for bonding foam pieces together. However, the adhesive contains a large percentage of water. Therefore if a foam assembly bonded with water-based adhesives is packaged before fully dried, mold, unpleasant odors, substrate material breakdown, and the like may develop. 
         [0002]    Further, even aside from the water of the water-based adhesives, foam can contain appreciable amounts of water, such as 1% to 2% water by weight, based solely on how it is stored. If stored in humid environments, the foam will retain a higher percentage of water weight compared to being stored in low humidity conditions. This water can also be a problem for mold and mildew growth when the mattress is packaged. This water, even on its own, can cause issues, and these issues may be compounded when water-based adhesives are present. 
         [0003]    In particular, in foam mattress assembly and other assembled foam products, a fast growing trend in industry is to compress said assemblies into a box that may be shipped directly to customers. The boxes are sized such that traditional package shipping companies can handle them. These foam mattresses are laminated, and then enclosed in an impermeable plastic bag which is vacuumed and compressed so that it fits into the mattress boxes. Vacuuming alone to compress the package does not adequately extract water from the package, so trapped moisture is a common occurrence. Currently, the primary solution for this problem is to simply let the foam assemblies rest for a certain time period. However, this slows down the manufacturing and shipping process, and requires extra storage space at the manufacturing site. 
         [0004]    Therefore, what is needed is a system that may allow for rapid drying of the assembled adhered foam elements to allow for a shorter processing time between assembly and packaging. 
       SUMMARY 
       [0005]    The subject matter of this application may involve, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of a single system or article. 
         [0006]    In one aspect, the present invention involves an apparatus configured to remove moisture from laminated foam assemblies. The present invention operates generally by drawing air through a foam product. In a particular aspect, a vacuum box is provided that provides walls and a base to support a foam assembly that can be quickly and easily moved into and out of the box for drying of the adhesive by drawing air through the foam assembly. As this air passes through the foam assembly, moisture within the foam, either from the atmosphere and/or water based adhesive is evaporated, allowing for more effective, safe, and sanitary long term packaging. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0007]      FIG. 1  provides an elevation view of one embodiment of the foam drying apparatus of the present invention. 
           [0008]      FIG. 2  provides a side view of an embodiment of the present invention. 
           [0009]      FIG. 3  provides a side view of another embodiment of the present invention. 
           [0010]      FIG. 4  provides an elevation view of yet another embodiment of the present invention. 
           [0011]      FIG. 5  provides a side view of still another embodiment of the present invention. 
           [0012]      FIG. 6  provides a side view of yet still another embodiment of the present invention. 
           [0013]      FIG. 7  provides an elevation view of another embodiment of the present invention. 
           [0014]      FIG. 8  provides an elevation view of another embodiment of the present invention. 
           [0015]      FIG. 9  provides a side view of an embodiment of an adjustable side wall of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The present invention concerns an apparatus to reduce or eliminate water from a foam assembly. The present invention involves an apparatus that is configured to draw air through laminated foam assemblies such as foam mattresses and the like. Generally, the apparatus provides a base area and sidewalls on which the foam assembly may be placed and supported. For example, the foam assembly may be placed on a rack, rollers, and the like. Below, or otherwise adjacent to the base, a vacuum attachment allows a vacuum to be drawn on, and applied to, all or nearly all of a surface area of one face of the foam assembly. The vacuum attachment applies the reduced pressure to the surface area of the foam assembly. The apparatus is configured to be operated for a period of time on a foam assembly sufficient to adequately dry the foam assembly. This time frame may vary depending on the variables particular foam assembly such as its size and the amount of adhesive used. Air on the opposite side of the foam assembly is drawn through it towards the vacuum attachment. As the air passes through the foam assembly, moisture is evaporated and carried out of the foam. 
         [0017]    As used herein, a foam assembly may be any assembly that comprises two or more foam pieces laminated together using an adhesive. It is even possible that a foam assembly may be a single foam element. Foam assemblies may be any size, shape, foam type(s), and configuration, without straying from the scope of the present invention. 
         [0018]    In one embodiment, the present invention provides a vacuum box for drying rectangular foam assemblies, for example mattresses. The box is formed of an air permeable base on which a foam assembly may rest, as well as side walls to cover the sides or part of the sides of the foam assembly held therein. A vacuum attachment, such as a pipe and a spacing underneath the base allows a low pressure zone to be applied to a foam assembly resting on the base. In some embodiments, the base may have a plurality of rollers so as to allow the foam assembly to be rolled into position for drying. 
         [0019]    In a particular embodiment, around a perimeter of the vacuum box are four side walls configured to abut the sides of the foam assembly. In some embodiments, one or more walls may have vents allowing air to pass through. For example, these vents may be located at typical core heights where two foam layers are adhered together. In one embodiment shown, vents are positioned at 4, 5, 6, 7, 8, and 9 inches from a base of the foam assembly. By allowing air flow over the sides of the foam assembly, particularly at adhesion points, the adhesive may be dried more quickly particularly at the seams. 
         [0020]    Some embodiments of the drying system may be particularly configured and sized for mattress drying (though it may be used for the drying of any foam assembly). As such, one of the side walls may be adjustable to adapt to varying widths of mattresses as shown in the various broken vertical lines of  FIG. 4  (discussed in detail below). Further, an end wall may be adjustable to adapt to varying lengths of mattresses as shown by the various broken horizontal lines of  FIG. 4 . Once the box is sized, the foam assembly may be moved or slid into position, vacuum drawn, and then moved or rolled out of the box. Sizing of the vacuum area may vary greatly and is not a limiting aspect of the present invention. 
         [0021]    A stationary side or end wall may be equipped with inflatable bag portions along all or part of the side wall. These inflatable bag portions allow a seal to be formed against both side walls by urging against the foam assembly once inflated, and in turn pushing it against the opposing side wall. By forming this seal, air is more directly forced through the foam assembly, increasing air flow through the assembly which in turn increases drying rate of the adhesive. A similar inflatable bag structure may be applied to at least one end wall as well. The bags may then either be deflated to release the foam assembly, or may remain inflated until a differently sized foam assembly is to be dried in the vacuum drying assembly. 
         [0022]    Common mattress sizes include: 
         [0023]    Twin: 38″×74.5″ 
         [0024]    Twin XL: 38″×79.5″ 
         [0025]    Full: 53″×74.5″ 
         [0026]    Full XL: 53″×79.5″ 
         [0027]    Queen: 60″×79.5″ 
         [0028]    King: 76″×79.5″ 
         [0029]    California King: 71″×83.5″ 
         [0030]    Accordingly, the adjustable side and end walls of the vacuum box may be adjustable to these sizes to be used for all common mattress sizes. In one embodiment, the adjustable walls may be adjusted to fit within close tolerances (+/−one inch) to these sizes. In another embodiment, the adjustable walls may be configurable to leave a minor spacing between the expected size and the walls, and then the inflatable bags, pads, or the like, may be used to ensure proper sizing. This embodiment may allow for movement into and out of the vacuum box without wall interference or friction. In one non-limiting example, the adjustable walls may be configured to be spaced as follows for the different mattress size operation: 
         [0031]    Twin: 39″×75″ 
         [0032]    Twin XL: 39″×81″ 
         [0033]    Full: 54″×75″ 
         [0034]    Full XL: 54″×81″ 
         [0035]    Queen: 61″×81″ 
         [0036]    King: 77″×81″ 
         [0037]    California King: 72″×85″ 
         [0038]    In some embodiments, a heat source may be present on an opposite side of the foam from the vacuum draw side. The heat source serves to heat air that is drawn towards and through the foam assembly. The heat source may be any structure capable of increasing the temperature of ambient air. For example, a convection heat source, infra-red heat source, and the like. In a particular further embodiment, a fan or other air moving structure may force air, such as heated air, towards the foam assembly to further enhance the transport of the air through the foam assembly. Heated air has a greater moisture transport capacity compared to ambient temperature air. Therefore, as heated air is urged through the foam assembly, it picks up more moisture from the foam, allowing the foam to dry faster. In varying embodiments, heated air may range from 80-275 degrees Fahrenheit, but lower and higher temperatures may also be used without straying from the scope of this invention. Typically, embodiments of foam being dried may be able to handle temperatures of up to 250 to 275 F for short periods of time without damage. 
         [0039]    In another embodiment, desiccated, dehumidified, or otherwise dry air may be used for passage through the foam. By passing dry air, as opposed to moist ambient air, through the foam assembly, moisture absorption may be more rapid and efficient. The term “dry air” is used herein to refer not only to fully dry air, but also air that has a lower moisture content than surrounding ambient air. The dry air may be used in addition to the heat source (providing hot, dry air), or as an alternative to it. This dry air embodiment may be particularly useful in non-air conditioned assembly facilities that may have higher than normal humidity levels. 
         [0040]    The present invention has, in initial tests, provided drastically enhanced performance compared to the prior art method of simply letting the foam assemblies rest at ambient conditions. For example, substantial and sufficient drying and adhesion (foam tear) has been achieved in only five minutes of drying using this drying apparatus. Equivalent drying and adhesion of the foam assembly at ambient conditions may take up to six hours or more. Depending on permeability and moisture content of the foam assembly, more or less time on the drying apparatus may be required, however this applies even more so when drying at ambient temperatures. For example, if ten to fifteen minutes on the drying apparatus of the present invention is required, the drying time at ambient temperature may be ten to twelve hours. As such, even if additional time is required on the drying machine, it is on the order of minutes, as opposed to hours using prior art techniques. 
         [0041]    In one embodiment of drying a foam mattress, a top foam layer may be coated with adhesive, and then placed on a core foam layer. In such an embodiment, either the top layer or core may be closest to the vacuum source that draws the vacuum, however typically the core layer will be facing the vacuum attachment. Further, by drawing air through the foam, there is a compression of the layers together, which may aid in final adhesion. 
         [0042]    Any type of foam assembly may be dried using the present invention. As such, the apparatus, rack, funnel, body providing structure for the apparatus, and the like may be any shape and size to receive a particularly sized foam assembly for drying. Further, in some embodiments, an adapter may be installable to allow for varied sizing, while maintaining a snug fitting around the foam assembly so that air does not simply go around the foam assembly instead of through it. Similarly, the present invention may be operated in any orientation, whether that be drawing air downward, to a side, or upwards, without straying from the scope of the present invention. 
         [0043]    In one exemplary embodiment of operation, a laminated foam assembly product may be either transferred from its assembly position onto a support rack of the drying assembly, or may be assembled in place on the drying assembly. Once the foam elements are assembled and laminated together by water-based adhesive, the system may be activated. Activation involves drawing a low pressure area so that the foam assembly is between the low pressure area and the atmosphere, which in turn draws air through the foam assembly. In some embodiments, as noted, this air may be heated by a heating device adjacent to the foam assembly on the opposite side of the assembled foam from the vacuum attachment. In a particular embodiment, air being drawn through the foam assembly by the drying apparatus may be initially heated for part of processing time, and then may be ambient temperature or otherwise cooler than the heated air for part of the processing time. In this embodiment, the foam assembly may be cooled so as not to be excessively hot during packaging. For example, in a five minute drying process, an initial three minutes may be using heated air, while a last two minutes may be using cooler air than the heated air. 
         [0044]    Turning specifically to the figures, multiple embodiments of the present invention are provided. A simple embodiment of the drying system of the present invention is shown in  FIGS. 1 and 2 . In these figures, the invention is formed as a body having side walls  10  and end walls  11 . A rack  21  serves as an air permeable base on which a foam assembly may rest. An air outlet  13  below the rack  21  is configured to have a vacuum pump (not shown) attached thereto in order to draw a low pressure below the rack  21 , causing exterior air to pass through the rack  21  (and any foam assembly thereon). A funnel  22  may provide an effective structure of the vacuum attachment to draw the low pressure zone over an entire area of the rack  21 , though it should be understood that any structure may be used. 
         [0045]      FIG. 3  provides a side view of an embodiment of the drying system having a foam assembly  12  resting on rack  21 . The foam assembly  12 , in this embodiment, is formed of a top foam layer  12 A, and a bottom foam layer  12 B, bonded together by an adhesive  12 C. A heat source  31  heats air  32  as it passes towards the foam assembly  12  because of the low pressure zone applied by the vacuum source (not shown) through the air outlet  13  and funnel  22 . Such an embodiment utilizes the ability of heated air to carry more moisture than cool air, which allows more effective removal of water from the foam assembly by the heated air  32  passing through. This air collects moisture and becomes moist air  33  after passing through foam assembly  12 . Moist air  33  moves through the funnel  22  and outlet  13  in direction A as directed by the outlet  13 . 
         [0046]      FIGS. 4-6  provide various views of embodiments of a drying system with an adjustable base to allow for drying of various sized foam assemblies. The device has a stationary side wall  40 , an adjustable side wall  42 , an adjustable end wall  43 , and an end wall  41 . In some embodiments, sidewall  40  and end wall  41  may have a padding or inflatable bag portion  55  to provide pressure against a foam assembly to control air entry at the foam-wall interface. A similar padding or inflatable bag portion  52  may be provided on side wall  40 . As seen in  FIG. 4 , the adjustable end wall  43  and side wall  42  may be adjusted to a number of lengths L 1 , L 2 , and L 3 , and a number of widths W 1 , W 2 , W 3 , W 4 , and W 5 , for example. In a particular embodiment, the foam drying system may be integrated into a conveyor system. As such, a foam assembly may enter into the drying system area, be dried for a time period, and then conveyed out of the area using the conveyor rollers  54 . In such an embodiment, the foam may travel in direction D, for example. In a particular embodiment, end walls  41  and  43  may be able to be swung open to allow the foam assembly into and out of the drying base area. In the embodiment shown, hinges  51  allow this motion. Vents  53  are positioned on side wall  40 . These vents  53  allow air to enter the sides of the foam assembly. 
         [0047]      FIGS. 7 through 9  show various embodiments of another embodiment of the adjustable-area system. In this view, adjustment of the area of the drying device is achieved by adjustable walls  72  and  73 , which are connected to air impermeable sheets  74  and  75  respectively. Typically air impermeable sheets  74 ,  75  are a rubberized or plastic material, but may also be a heavy fabric, or other membrane. The sheets can be connected to a rolling structure, for example as shown in  FIG. 9 , rolled area  91  and spool  92 , to allow the sheet to be retracted by rolling and extended by unrolling. In varying embodiments, only an adjustable end wall or an adjustable side wall may be used, or both may be employed. The adjustable walls  72 ,  73 , may be slideable or otherwise movable to the desired position, and fixable in this position during drying operation. This allows for rapid adjustment of the device for variously sized foam assemblies with minimal downtime. The sheets  74 ,  75  may be guided by tracks on their ends. Further, each sheet  74 ,  75  may have an upwardly extending side wall  73  which provides a face to abut a foam assembly edge. The side wall  73  may be supported in any manner, for example at its ends, at its base, on tracks, and the like. In some embodiments, a force-applying device such as a piston or spring may be utilized to urge the side wall against a foam assembly therein. This structure may function to provide a more air-tight seal between the side wall and edge of the foam assembly to prevent air from leaking between the two. 
         [0048]    While several variations of the present invention have been illustrated by way of example in preferred or particular embodiments, it is apparent that further embodiments could be developed within the spirit and scope of the present invention, or the inventive concept thereof. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.