Patent Publication Number: US-2006013062-A1

Title: Lightweight foam carburetor

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention is directed to a carburetor nozzle device and, more particularly, to a carburetor device which attaches to the end of a water supply line for mixing and agitating water and a foaming agent in order to produce a uniform foam mixture having consistent bubble size for subsequent use in the manufacture of lightweight insulating concrete.  
      2. Discussion of the Related Art  
      Lightweight concrete is used extensively in the construction of buildings, and particularly in the installation of roof decks and related roof systems. When installing a roof deck on a building structure, lightweight concrete is disbursed, in a slurry coat, to form a topping layer of insulation over underlying roofing materials. Lightweight concrete typically consists of a combination of Portland cement, one or more foaming agents, water and possibly other chemical agents. To insure proper distribution of the lightweight concrete, prior to curing, it is important to discharge the lightweight concrete mixture on the roof deck shortly after the mixing process. Presently, the process of manufacturing lightweight concrete for onsite installation involves the use of one or more compressors, a pressurized tank for holding chemicals, a separate cement mixer, a concrete pump and an elaborate series of hoses for directing water, cement, foaming agents and other chemicals to be mixed and discharged in rapid action. Typically, a carburetor is attached to the end of a water supply line for mixing water with a foaming agent which is discharged under pressure prior to introduction with the cement in the concrete pump. The carburetors presently used in the industry typically have a cylindrical body with a stainless steel cloth or other wire bundle packed within the interior. Water and a foaming agent are forced through the stainless steel cloth or other wire bundle to generate a foam mixture. This foam mixture is then introduced with the Portland cement in the concrete pump. The foam mixture is blended with the concrete and pumped through a supply line for discharge in a slurry coat, forming the topping layer of insulation over the underlying roofing materials.  
      The presently used methods of onsite manufacturing of lightweight concrete present several problems and concerns. Specifically, the carburetors presently used for mixing water and the foaming agent are not suited to produce a uniform foam mixture having consistent bubble size. This results in clusters of smaller bubbles around larger bubbles to produce thinner concrete walls between the bubble voids. These thinner concrete walls reduce the structural integrity of the lightweight concrete layer. Moreover, the bubble distribution at the top surface produces a thin surface layer that is weak in spots, creating a significant variance in uplift or pull strengths throughout the roof deck in violation of most building codes.  
      It has been discovered that the production of a foam mixture having larger and more consistent bubble size produces a lightweight concrete product with more uniform bubble (i.e. void) dispersion and thicker concrete walls between voids, thereby producing greater and more uniform uplift or pull strength throughout the roof deck structure.  
      Accordingly, there is an urgent need in the roof construction industry for a lightweight foam carburetor which produces a uniform foam mixture having consistent bubble size for advantageous disbursal throughout a lightweight concrete mixture.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to a device for use in the manufacture of lightweight concrete. The device includes a first end having a reduced diameter portion for connection to a water supply line, an opposite second discharge end, and a cylindrical body between the first and second ends. An interior chamber within the cylindrical body has mesh screens at the opposite ends. Beads are filled within the interior chamber, between the mesh screens. In a preferred embodiment, the beads are formed of a plastic composition or stainless steel and range in diameter between four and seven millimeters. Water and a foaming agent, introduced under pressure through the first end of the device, are mixed and agitated while passing through the bead packed interior chamber to produce a resultant foam mixture of consistent bubble size. The foam mixture is discharged from the open second end of the device and is mixed with Portland cement to produce lightweight insulating concrete for use in the installation of roof decks of a building structure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      For a fuller understanding of the nature of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which:  
       FIG. 1  is a side view, and partial cross-section, illustrating the carburetor device of the present invention connected to the end of a water supply line with a foam agent introducing inlet;  
       FIG. 2  is a cross-section of a lightweight concrete layer of a roof deck illustrating proper bubble size and dispersion of foam mixture throughout the concrete. 
    
    
      Like reference numerals refer to like parts throughout the several views of the drawings.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring initially to  FIG. 1 , the lightweight foam carburetor device of the present invention is shown and is generally indicated as  10 . The carburetor device  10  includes a first end portion  12  and an opposite second end  14 . The first end portion  12  includes a reduced diameter extension  16  which connects to the end of a water supply line WL and a reducer  18  which changes in diameter from approximately 4 inches to 1 or 1½ inches. The reducer  18  extends from the reduced diameter extension  16  and enlarges at the first end  22  of a main cylindrical body  20 . The cylindrical body  20  extends from the first end  22  to an opposite open end  24  at the second end  14  of the carburetor device. In a preferred embodiment, the cylindrical body  20 , reducer  18  and reduced diameter extension  16  are manufactured as three separate interconnected components. However, the combined assembly of the reduced diameter extension  16 , reducer  18  and cylindrical body  20  may be formed as a single, integral component. The wall structure of the reduced diameter extension  16 , reducer  18  and cylindrical body  20  is preferably formed of PVC or stainless steel.  
      Mesh screens are fitted transversely across the interior of the cylindrical body. More specifically, a first mesh screen  30  is installed near the first end of the cylindrical body and a second mesh screen  32  is installed near the opposite open end of the cylindrical body  20 . In a preferred embodiment, the mesh screens are manufactured of stainless steel and have a mesh size ranging between 1/16th and ⅛th of an inch.  
      Round beads  40  are packed between the screens  30 ,  32  to fill the interior chamber of the cylindrical body defined between the screens and the surrounding cylindrical wall structure. In a preferred embodiment, the round beads  40  are formed of a plastic composition or stainless steel and range in diameter between 4 millimeters and 7 millimeters. In one preferred embodiment, the beads  40  range in diameter between 5 millimeters and 6 millimeters.  
      A valve  50  is provided along the reduced diameter extension  16  and is operable between an open position to permit fluid flow therethrough and into the interior chamber of the cylindrical body, as indicated by the arrows, and a closed position to interrupt fluid flow through the carburetor device. The connecting water supply line WL includes a foaming agent introduction feed F. With the valve  50  open, water and a foaming agent are directed, under pressure, through the reduced diameter extension and into the main interior chamber of the cylindrical body. More specifically, the water and foaming agent are directed through the first mesh screen  30  and through the packed arrangement of round beads, causing the foaming agent and water to be thoroughly mixed and agitated to produce a uniform foam mixture having consistent bubble size. The resultant foam mixture is discharged from the open second end  14  of the cylindrical body for introduction into a concrete pump, wherein the foam mixture is blended and mixed with Portland cement.  
       FIG. 2  illustrates an ideal production of a lightweight concrete layer, wherein consistent voids (produced by bubbles in the foam mixture) are uniformly disbursed throughout the Portland cement.  
      While the instant invention has been generally shown and described in accordance with a preferred and practical embodiment thereof, it is recognized that departures from the instant disclosure are contemplated within the spirit and scope of the present invention.