Abstract:
Panels for building construction are formed of industrial or agricultural wastes or environmental materials supplied in layers together with mesh layers in stacked steel molds. Male molds are received in the first molds, each having an inflatable cover about a rigid tube. By pressurizing the volume between the tube and cover the cover is expanded to pressurize the filler material within the mold. Heated liquid is utilized to facilitate hardening of the materials within the mold. Vibration is also applied to the liquid and the molds are rotated about a horizontal axis. The molds are opened and the male molds removed and wall panels with insulated interior passages are provided.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to wall panels and methods and apparatus for fabricating wall panels for use in buildings and particularly relates to wall panels and methods and apparatus for forming building wall panels from waste or recycled materials.  
         [0002]     Current building materials are typically fabricated from raw materials, e.g. wood, minerals or chemicals. These materials require substantial engineering efforts and expense to not only process the materials when building new construction but also to break down or dispose of those materials when the building is of no longer any use and requires demolition. Thus, those building materials burden the environment when the building is renovated and/or demolished. While there has been an increasing trend toward use of environmentally friendly building materials, waste material from even those environmentally friendly materials during construction, renovation or demolition are oftentimes not reused. Accordingly, there has developed a need for the fabrication of principal components of a building, e.g. wall panels which may utilize as constituent elements almost any waste material available in the geographic location of the production facility.  
         [0003]     In accordance with a preferred embodiment of the present invention, waste materials, e.g., as found in nature and not residual demolished construction material, such as rice shells, tuff, sunflower peduncle, cotton pod peduncle, forest refuse, straw, and other locally available materials may be used in the fabrication of wall panels in conjunction with a suitable binder. Thus these materials may be shredded, i.e., reduced in size for use in the fabrication methods and apparatus hereof for the formation of wall panels that are durable, enduring, inexpensive, have requisite strength characteristics and insulation properties and can be readily and easily applied in construction during hot and cold extreme weather conditions. For example interior wall panels may be formed having wall thicknesses ranging from 10-15 centimeters to 20 centimeters, a width of about 120 centimeters and a length that may vary from 280 centimeters to 300 centimeters. It will be appreciated that the materials forming the wall panels may be cut to fit the required sizes. For exterior walls, similar materials may be utilized with an external layer highly resistant to external environmental elements, such as heat, humidity, temperature variation and which has high heat insulation properties. Likewise floor and ceiling panels may be manufactured to the appropriate size, thickness and strength to carry vertical loads.  
         [0004]     In a preferred embodiment of the present invention, there is provided a method of fabricating panels for use in a building comprising the steps of:  
         [0005]     (a) providing a first mold having a bottom wall and side walls;  
         [0006]     (b) disposing a first layer of a first material within the first mold;  
         [0007]     (c) disposing a first layer of mesh material overlying the first layer of material;  
         [0008]     (d) disposing a first layer of filler material overlying the first layer of mesh material;  
         [0009]     (e) locating a plurality of male molds at spaced locations from one another within the first mold and overlying the first layer of filler material.  
         [0010]     (f) disposing a second layer of a filler material within the first mold about said male molds and overlying the first layer of filler material;  
         [0011]     (g) disposing a second layer of mesh material overlying the second layer of filler material;  
         [0012]     (h) disposing a second layer of a second material within the first mold and overlying the second layer of mesh material;  
         [0013]     (i) closing the first mold;  
         [0014]     (j) expanding the male molds within the closed first mold to pressurize the first, second and filler materials;  
         [0015]     (k) removing the male molds from the first mold; and  
         [0016]     (l) removing the panels from the first mold; and  
         [0017]     (m) curing the first, second and filler materials.  
         [0018]     In another preferred embodiment of the present invention, there is provided a method of fabricating panels for use in a building comprising the steps of:  
         [0019]     (a) providing a plurality of molds, each having a bottom wall and side walls;  
         [0020]     (b) disposing a first layer of a first material within each mold;  
         [0021]     (c) disposing a first layer of mesh material overlying the first layer of material in each mold;  
         [0022]     (d) disposing a first layer of filler material overlying the first layer of mesh material in each mold;  
         [0023]     (e) locating a plurality of male molds at spaced locations from one another within each mold and overlying the first layer of filler material;  
         [0024]     (f) disposing a second layer of a filler material within each mold about said male molds and overlying the first layer of filler material;  
         [0025]     (g) disposing a second layer of mesh material overlying the second layer of filler material in each mold;  
         [0026]     (h) disposing a second layer of a second material within each mold and overlying the second layer of mesh material;  
         [0027]     (i) closing each mold;  
         [0028]     (j) stacking the plurality of molds one on top of another;  
         [0029]     (k) expanding the male molds within the stacked molds to pressurize the first, second and filler materials in each mold to form the panels in the molds;  
         [0030]     (l) removing the male molds from each mold;  
         [0031]     (m) removing the panels from each mold; and  
         [0032]     (n) curing the first, second and filler materials within each mold.  
         [0033]     In still another preferred embodiment of the present invention, there is provided a mold apparatus for forming building panels comprising a first mold having a bottom, sides and a removable top cover defining a mold volume; and a plurality of elongated male molds for disposition within the mold volume and spaced one from the other; each male mold including an elongated rigid tube and an overlying flexible cover, the tube including a fluid inlet for flowing fluid into and within the tube and at least one aperture in communication with a second volume between the cover and tube for flowing fluid from within the tube through the aperture, the tube including an outlet in communication with the second volume for flowing fluid therefrom through the outlet.  
         [0034]     It will be appreciated that a wide variety of waste materials may be utilized in the formation of the wall panels in accordance with the preferred embodiment of the present invention. These range from agricultural wastes to industrial wastes, as well as recycled waste material. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]      FIGS. 1A and 1B  are perspective views of panels constructed in accordance with the preferred embodiments of the present invention;  
         [0036]      FIG. 2  is an exploded perspective view illustrating the various components of a panel between top and bottom molding plates;  
         [0037]      FIG. 3  is an enlarged cross-sectional view through the mold illustrating the male mold within the first mold;  
         [0038]      FIG. 4  is a diagrammatic illustration of the process for forming the wall panels;  
         [0039]      FIG. 5  is a perspective view with parts exploded and broken out for ease of illustration showing the male mold within the panel within the first mold; and  
         [0040]      FIGS. 6A-6H  are diagrammatic illustrations of the method of forming the wall panel. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]     Referring to the drawing figures particularly to  FIG. 1 , there is illustrated a wall panel constructed in accordance with the preferred embodiment of the present invention. The panel  10  may comprise a wall panel, a ceiling panel or a floor panel. The panel may be fabricated to various sizes. For example a typical interior wall panel may have a wall thickness from 10-20 centimeters, a width of 120 centimeters and a length that may vary from 280 to 300 centimeters. Panels used as exterior walls in building construction must be highly resistant to environmental elements such as heat, humidity, rain and temperature changes with high insulation properties. Thus, as illustrated in  FIG. 1A , a plurality of openings  12  extend the length of the panel in a single layer thereof and are provided during fabrication of the panel as set forth below. Alternatively, multiple layers of openings may be provided in a single panel. For example, as illustrated in  FIG. 1B , three layers of openings  12  are provided in a single panel with one layer of openings  12  extending 90° relative to one or more adjacent layers of openings. The openings provide for insulation. Where the panels form floor or ceiling units, the size and thickness of the panels can be varied to carry the vertical loads.  
         [0042]     The panels may be fabricated from a wide variety of materials varying from waste materials such as agricultural and industrial wastes to naturally-occurring materials such as volcanic tuff. The fabrication of the wall panels preferably occurs near the geographic location of the waste or natural materials to minimize loading and transportation costs from the fabrication site to the building site. Examples of such materials are volcanic tuff mixed with a bonding material such as gypsum, sunflower peduncle mixed with formaldehyde, cotton pod peduncle mixed with a cement, and other filler materials, such as rice shells, straw, forest refuse mixed with a suitable bonding material. It will also be appreciated that difference surface materials may be provided depending upon whether the end use of the panel is an external wall, an internal wall or a floor or ceiling component of the building. For example for an external wall, layers of material may comprise an external surface material, reinforcing mesh, a filling material, a mesh and an inner surface material. For internal wall panels, the materials may comprise an internal surface material, a mesh, a filling material, a mesh and an internal surface material. For floor or ceiling panels, the panel may comprise a flooring or ceiling material, a mesh, a filling material, a mesh and an inner surface material.  
         [0043]     Referring to  FIG. 2 , there is schematically illustrated a mold having top or cover and bottom mold plates  14  and  16  respectively. The molds are preferably formed of steel with appropriate thickness and having side walls  18  ( FIGS. 6A-6H ). Preferably the interior surfaces of the steel molds are coated with a non-sticking material, e.g., Teflon® to facilitate removal of the panel from the mold. The panels are also preferably formed with one or more layers of a mesh material as illustrated at  20  in  FIG. 2 . The reinforcing mesh material may comprise a fiber mesh, a wire mesh or glass fiber mesh or any other type of mesh material which affords appropriate strength and resistance to external loadings.  
         [0044]     As will be appreciated, different materials are utilized for the external and internal surfaces of each panel depending on the nature of its use. Thus these different materials are placed inside the mold in sequence as explained below. For example, for an exterior panel having both an interior and external surface, a fine grain material and a filling grain material such as volcanic tuff but utilizing particles of different sizes may be utilized. For example, for volcanic tuff fine grains between 5-1.5 millimeters may be used as a first layer forming an interior surface. For forming the exterior surface, volcanic tuff particles crush to 5-6 millimeters particle size may be utilized each, of course, being mixed with a bonding agent such as cement. Thus as illustrated in  FIG. 2  an interior surface material of fine particle size is designated  22  and an exterior panel surface of more coarse particle size is designated  24 . Intermediate the exterior and interior surface materials is a filler material  26  which may comprise a similar material of the same or different particle size as the exterior or interior surface materials or may comprise a different material entirely.  
         [0045]     Referring now to  FIG. 3 , a plurality of male molds generally indicated  28  are utilized in the fabrication of the panel. Each male mold includes a preferably cylindrical tubular steel or aluminum body  30  which extends longitudinally approximately the length of the panel but terminating in a closed end  31  short of the length of the panel. At the opposite end, a pair of end plates  32  and  34  form a chamber  36 . A side wall  44  of the first or steel mold includes a plurality of openings to accommodate an extension  38  of the aluminum or steel male mold  28 . The tube  30  includes an inlet  40  for flowing a fluid into the volume  42  downstream of the chamber  36  and an outlet  37  in communication with the chamber  36 . The tube  30  has an overlying flexible and/or resilient cover preferably formed of flexible rubber  46  extending the full length of the tube  30 . Apertures  48  near the closed end of tube  30  lie in communication with the interior of the flexible cover  46 . Apertures  50  are also formed in the tube  30  communicating between chamber  36  and the interior surface of the cover. The end of the tube adjacent the mold openings forms a tight fit and a seal may be provided. A typical wall panel of average width of about 120 cm. requires about fifteen molds  28  with diameters of about 50 mm.  
         [0046]     Referring to  FIG. 4 , a plurality of superposed molds are illustrated with the fluid inlet and outlet tubes  40  and  37  for each mold. The fluid inlet tube  40  is coupled to a source of heated fluid  52  while the outlet tube  37  is coupled to a source of fluid at a colder or reduced temperature  54 . The fluid inlet line  40  is coupled to a compressed air unit  56  via line  58 . Additionally, a vibration unit  60  for vibrating the fluids applied to the male molds is illustrated.  
         [0047]     To form these panels and referring particularly to  FIGS. 6A-6H , the uncovered bottom and side molds  16  and  18  receive a first layer of first material  22 . A mesh material for example material  20  is then laid over the first layer  22  as illustrated in  FIG. 6B  In  FIG. 6C , a first layer of a filler material  26 a is applied overlying mesh material  20 . The male molds  28  are also inserted through apertures in the side wall of the mold to overlie the mesh material  20  and filler material  26   a.  In  FIG. 6D , a second layer of filler material  26   b  is disposed in overlying relation to the male molds and the first layer of filler material  26 . In  FIG. 6E , a second layer of mesh material  20  overlies the second layer of filling material  26   b.  Finally in  FIG. 6F , the final or second layer of a second material  24  is applied over the mesh material  20 . In  FIG. 6G , the cover  14  for the mold is applied and molds may be stacked one on top of the other as illustrated. Preferably the various materials, i.e., the first and second filler materials may be sprayed into the molds.  
         [0048]     Once the steel molds are sealed, pressurized and heated liquid is applied to the male molds  28 . Thus, heated liquid from source  52  is pumped into the interior of the male mold tube  30  and exits via apertures  48  into the volume between the outer surface of tube  30  and the interior surface of the flexible cover  46 . The flexible cover thus expands creating a volume between the rigid tube and the flexible cover and pressurizes the material within the mold increasing its diameter in a typical panel to about 75 mm. This effectively distributes the filling material by squeezing out any and all gaps in between the mold material and the surfaces of the steel molds. Upon reaching sufficient pressurization, the vibration unit  60  is applied to the liquid so that the combined pressure and vibration is applied to the filler materials. After attaining a prescribed temperature to cure the filler material, which temperature may vary depending upon the filling material utilized, and the desired hardness, a cold liquid from source  54  is applied to the system. Thus, the liquid from source  54  may be supplied to the extension tube  37  for flow through apertures  50  into the volume between the flexible cover and the rigid tube displacing the heated liquid through apertures  48  and through extension tube  40  for return to the fluid source. Introduction of the cold liquid facilitates the curing process. The system is then depressurized by removing the fluid from the volume between the cover and the rigid tube as well as from the male molds, thereby returning the individual molds  28  to their approximate original diameter, e.g., about 50 mm. It will be appreciated that the pressurized heating water or oil and the cooling liquid are applied to inflate the flexible cover about the rigid tube  30  and that the flexibility and adjustability of the cover maintains a specified diameter through pressurization as well as the uniform distribution of the filling material and the elimination of bubbles and gaps that may form between the layers. The flexibility and adjustability of the rubber cover also compensates for any minor errors in the amount of filling material utilized.  
         [0049]     During the pressurization, vibration and curing process, the molds are rotated horizontally to allow any air bubbles that may have been formed on the surfaces, i.e. trapped between the wall panel surfaces and the mold plates to be absorbed back into the filler materials. After the panels have been cooled down and sufficient curing has occurred, the stacked mold system may be unstacked and male molds removed. Thus, the mold holes come into contact with open air for the purpose of continuing the curing process until curing ends during storage of the fabricated panels.  
         [0050]     It will be appreciated that during the foregoing described fabrication process the pressurization, vibration, temperature and cooling phases are separate from and independent of each other. Consequently it is possible to make immediate and independent adjustments as required in any of these four phases of the production.  
         [0051]     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.