Patent Publication Number: US-7220457-B2

Title: Air atomizing assembly and method and system of applying an air atomized material

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 10/164,738 filed Jun. 6, 2002 now U.S. Pat. No. 6,951,310. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a spray head air atomizing assembly and more specifically to an air atomizing assembly to control the flow of atomizing air in a fluid spray or other delivery device such as an air sprayer for spraying paints, adhesives, coatings, and other semi-liquid materials. The invention also relates to a method and system of spraying or applying such materials by using the atomizing air or air stream as a vehicle for delivering catalyst, an agent, moisture or other component to the application fluid and of conditioning the application fluid. 
     2. Description of the Prior Art 
     Two common types of spray or delivery devices exist for spraying or delivering a fluid to a substrate. One such device is a so-called airless type sprayer or delivery device in which an application fluid is forced through one or more nozzle openings at high pressure. With this type of device, the fluid is atomized or disbursed into tiny droplets as a result of the pressurized fluid passing through the nozzle opening. 
     A second such device is an air or air atomized spray gun or delivery device in which the application fluid passes through a nozzle orifice, at pressures usually much lower than the pressures employed with airless spraying, in combination with atomizing air flowing through a plurality of air orifices surrounding the nozzle opening. The atomizing air functions to atomize or disperse the application fluid after its exit from the nozzle opening. 
     While many of the air atomizing assemblies of the prior art are generally acceptable when being used to atomize relatively low viscosity materials such as paint which , because of their physical characteristics, are broken up and atomized easily, the performance of such assemblies is limited and less than satisfactory when used to atomize high viscosity materials (in excess of about 3,000 centipoises) and materials which have a high surface tension such as epoxies, urethanes, polyureas and other adhesives. These high viscosity and high surface tension materials are difficult to atomize and thus tend to “string” a lot as the application material travels from the spray nozzle to the substrate. 
     Further, in prior art air atomizing sprayers or application systems, the atomizing air has been used primarily as a means to atomize or disperse the application fluid, with the introduction of secondary reaction components or other agents, catalysts and components being accomplished via other conventional means. 
     Accordingly, there is a need in the art for an improved air atomizing assembly, and more particularly a need for an air atomizing nozzle assembly which provides improved atomization of both conventional low viscosity materials such as paints as well as materials which have a relatively high viscosity and/or a high surface tension such as adhesives and the like. There is also need in the art for improved methods and systems of conditioning the application fluid and introducing and mixing secondary reaction components, agents and catalysts with the application fluid. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved spray head and air atomizing assembly which overcomes many of the limitations of the prior art. This atomizing assembly is applicable to conventional low viscosity materials such as paint, but is particularly applicable to atomizing materials which have a relatively high viscosity and a high surface tension such as adhesives. 
     In general, the air atomizing assembly in accordance with the present invention may be used with a conventional air sprayer or other application device having a nozzle opening. Such air sprayer or application device may be provided with an application fluid supply tube or conduit for a single component material or with an elongated mixing tube for a two component material. In one embodiment, the air atomizing assembly of the present invention includes an air atomizing tip which has a generally outer conical or frustoconical surface that converges in the direction of the nozzle opening and a corresponding atomizing assembly cap which includes an inner conical or frustoconical surface that mates with a portion of the exterior conical or frustoconical surface of the atomizing tip. One of these conical or frustoconical surfaces is provided with a plurality of atomizing air flow paths or grooves which spiral along such surface as it converges. When the atomizing tip and cap are assembled so that their respective conical or frustoconical surfaces mate with one another, a plurality of air passages defined by the grooves are formed between the respective conical or frustoconical surfaces. The cross-sectional configuration of these air passages as they exit from the atomizing assembly have a generally flattened configuration and most preferably, a configuration in which the circumferential dimension of the passages is at least about twice the depth or radial dimension of such passages. Because of the generally flat shape of the air passages at the exit end of the assembly, the airflow has a shear effect on the exiting application fluid. This shear effect tends to break up and shear portions of the application fluid from adjacent portions and results in significantly improved atomization of the application fluid. This is particularly true for materials having a high viscosity and/or high surface tension. 
     In a further embodiment, the nozzle assembly includes means in combination with the above atomizing assembly or other atomizing assemblies for breaking up the stream of applied material prior to atomization to provide for more thorough atomization and to facilitate higher flow rates. In the preferred embodiment, this means includes providing a diverter orifice or other structure within the application fluid flow stream and/or providing a portion of the atomizing air within the application fluid flow stream itself. 
     In a still further embodiment, the atomizing tip and atomizing cap have exterior and interior mating surfaces, respectively, which are provided with surfaces of other than conical or frustoconical configurations to shape or control the spray pattern of the application fluid. One such other shaped surface comprises, in cross section, an elliptical configuration or a generally flattened configuration with radiused ends to provide a wider spray pattern. 
     The method aspect of the present invention includes utilizing the atomizing air in a conventional air atomizing sprayer or application device, or in an air atomizing sprayer or application device as described above, to provide a curing agent such as moisture, a catalyst or a secondary reaction component to the application material or to condition the application fluid. Such a method is particularly applicable to one part or two part materials which are moisture cured or which require other curing catalysts or agents. In such an application, the present invention involves introducing such moisture or other catalyst or agent as part of the atomizing air stream. Preferably, a quantity of such moisture, catalyst or agent is provided to sufficiently cure the application fluid. 
     A further aspect of the method in accordance with the present invention is to condition the application fluid by heating or cooling the atomizing air stream for the purpose of controlling the viscosity and/or the cure rate of the application fluid. 
     Details of the above and other embodiments of the apparatus and method in accordance with the present invention will become apparent with reference to the drawings, the description of the preferred embodiment and method and the appended claims. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded isometric view of a mixer assembly incorporating the spray head and atomizing assembly of the present invention. 
         FIG. 2  is a view, partially in section, of the mixer assembly of  FIG. 1  as viewed along the longitudinal axis. 
         FIG. 3  is an enlarged elevational end view of the forward or nozzle end of the mixer assembly. 
         FIG. 4  is an elevational side view of the mixer tip of the air atomizer assembly of the present invention. 
         FIG. 5  is an elevational front end view of the mixer tip shown in  FIG. 4 . 
         FIG. 6  is an enlarged view of one of the airflow grooves in the mixer tip. 
         FIG. 7  is an elevational side view of the air atomizing cap of the air atomizer assembly of the present invention. 
         FIG. 8  is an elevational front end view of the air atomizing cap of  FIG. 7 . 
         FIG. 9  is an elevational side view of the air nozzle body. 
         FIG. 10  is an elevational front end view of the air nozzle body shown in  FIG. 9 . 
         FIG. 11  is a view, partially in section, of the air atomizing cap retaining nut. 
         FIG. 12  is a view showing a variety of cross-sectional configurations of the spiral airflow grooves in the mixer tip of the present invention. 
         FIG. 13  is an isometric, fragmentary view of a further embodiment of a fluid application assembly of the present invention. 
         FIG. 14  is a view, partially in section, of the fluid application assembly of  FIG. 13 . 
         FIG. 15  is an elevational end view of a further embodiment of an air atomizing assembly in accordance with the present invention. 
         FIG. 16  is a view, partially in section, as viewed along the section line  16 — 16  of  FIG. 15 . 
         FIG. 17  is a view, partially in section, showing a further embodiment of an air atomizing assembly in accordance with the present invention. 
         FIG. 18  is an elevational end view of a further embodiment of an air atomizing assembly in accordance with the present invention. 
         FIG. 19  is a view, partially in section, as viewed along the section line  19 — 19  of  FIG. 18 . 
         FIG. 20  is a view, partially in section, as viewed along the section line  20 — 20  of  FIG. 18 . 
         FIG. 21  is an elevational end view of a further embodiment of an air atomizing assembly in accordance with the present invention. 
         FIG. 22  is a view, partially in section, as viewed along the section line  22 — 22  of  FIG. 21 . 
         FIG. 23  is an elevational end view of a further embodiment of an air atomizing assembly in accordance with the present invention. 
         FIG. 24  is a view, partially in section, as viewed along the section line  24 — 24  of  FIG. 23 . 
         FIG. 25  is a schematic diagram showing an apparatus and system for providing pressurized application fluid and pressurized atomizing air to a nozzle assembly in accordance with the present invention. 
         FIG. 26  is a view, similar to  FIG. 12 , showing various alternate cross-sectional configurations of airflow grooves. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     One aspect of the present invention relates generally to a spray head and an air atomizing assembly incorporated therein. As will be described in greater detail below, the spray head of the present invention may be used with an application fluid mixing assembly which in turn is designed for use with an application fluid spray or delivery device such as an air atomized paint sprayer or an air atomized spray or application device. Such sprayers or other application devices are used to deliver application fluids such as paints, adhesives, sealants, semi-liquids and the like, to a substrate. In describing this aspect of the present invention, the preferred embodiment will be described with respect to an air atomized paint or other application fluid sprayer. 
     A further aspect of the present invention relates to a method of spraying and more specifically to a method of spraying which utilizes the atomizing air or air stream as a vehicle for providing the application fluid with a curing agent, a curing catalyst, a reaction component or other secondary material or to condition the application fluid such as by heating or cooling the atomizing air to better control the viscosity, cure rates and/or other characteristics of the application fluid. The method aspect of the present invention is usable with the specific air atomizing assembly of the present invention as well as conventional air atomizing spraying and application assemblies of the prior and future art. 
     A further aspect of the present invention relates to a means for breaking up the stream of applied material prior to being atomized. This aspect of the invention is also used with the specific preferred atomizing assembly of the invention as well as conventional atomizing assemblies. 
     Both the method and apparatus aspects of the present invention have applicability to the deliverance of both single component materials as well as two or multiple component materials to a substrate. Two or multiple component materials are commonly applied through a mixing tube or the like to thoroughly mix the components prior to application. In contrast, thorough mixing is generally not required for single component materials which are commonly cured with moisture, light or other means. Thus no mixing tube is required for single component materials, although such materials can be applied through a mixing tube, if desired. The preferred embodiment for the embodiment of  FIGS. 1–14  will be described with respect to a two or multiple component material in which a mixing tube or the like is preferred. The invention, however, should not be construed as being limited to a two or multiple component system. 
     In the description of the present invention, terms such as forward end or rearward end may be used to describe surfaces or ends of particular elements of the invention. Accordingly, unless otherwise stated, the forward end of an element as used herein shall be considered as the end facing or closest to the nozzle outlet end of the mixer assembly, while the rearward end of an element will be considered as the end or portion of an element which faces or is closest to the pressurized fluid inlet end of the mixer assembly. 
     With reference first to  FIGS. 1 and 2 , the spray head of the present invention is part of a mixer assembly  10 . The mixer assembly  10  includes an elongated application fluid mixer body  11 , an application fluid mixer tube  12  and an air atomizer assembly comprising the air nozzle body  15 , the mixer tip  16 , the air atomizing cap  18  and the retaining nut  19 . The mixer body  11  is an elongated, generally tubular element having a generally cylindrical center opening  20  which extends from the forward end  21  rearwardly to an internally threaded application fluid inlet end  22 . As shown best in  FIG. 2 , a frustoconically shaped surface portion  24  extends between the rearward end of the cylindrical opening  20  and the internally threaded portion  22 . The forward end of the body  11  is provided with exterior threads  25 . The exterior surface of the mixer body  11  is provided with a pair of flats  26  near the rearward end  22  to rotationally restrain the mixer body  11  during connection of elements to the threaded surfaces  22  and  25  at the rearward and forward ends of the body. 
     The mixer tube  12  is an elongated tubular member having an exterior cylindrical surface  28  with dimensions approximating those of the inner cylindrical opening  20 . The mixer tube  12  also includes a rearwardly positioned annular surface portion  29  and a frustoconically configured exterior surface portion  27 . The forward end of the tube  12  includes a narrowed, nozzle end  31  and an application fluid nozzle opening or orifice  30 . 
     The interior of the tube  12  is generally hollow, except for internal baffle means  32  which causes the application fluid to flow in a turbulent circuitous path from its rearward end to the forward end of the nozzle opening  30 . The mixer tube  12  is designed to be positioned within the mixer body so that the outer cylindrical surface  28  engages the inner cylindrical surface of the opening  20  and so that the outer frustoconical surface  27  seats against the inner frustoconical surface  24 . Mixing tubes of the type illustrated in  FIGS. 1 and 2  are well known to those skilled in the art and are commercially available. 
     Although these elements can be constructed from conventional materials such as stainless steel, brass and other metals, they may also be constructed via injection molding or the like from various plastics such as nylon, polyethylene, polypropylene or various ultra high molecular weight (UHMW) materials. This is particularly true for elements of the atomizing assembly such as the tip  16  and the cap  18 . 
     The air atomizer assembly which is comprised of the air nozzle body  15 , the mixer or atomizing tip  16 , the air atomizing cap  18  and the retaining nut  19  is illustrated in exploded or combined form in  FIGS. 1 and 2 , with individual components being illustrated in  FIGS. 4–10 . 
     With specific reference to  FIGS. 4 and 5 , the mixer tip or air nozzle tip  16  is shown as a generally conical or frustoconical element having a forward end  34 , a rearward end  35  and a generally frustoconical surface portion  36  extending between the forward and rearward ends  34  and  35 . As shown, the surface  36  converges as it extends from the rearward end  35  toward the forward end  34 . The frustoconical surface includes an axis of revolution  13  which is concentric with the longitudinal axis  13  of the mixer assembly  10 . Both the rearward end  35  and the forward end  34  include generally planar annular portions which are oriented at right angles relative to the axis  13 . With reference to  FIG. 4 , the frustoconical angle “A” which the surface portion  36  forms relative to the axis  13  is at least about 5 degrees, more preferably is at least about 10 degrees and most preferably is about 15 to 25 degrees. 
     The interior of the mixer tip  16  as shown by the broken lines in  FIG. 4  includes a generally cylindrical opening  38  which extends rearwardly from the forward end  34  toward the rearward end  35  and a rearwardly positioned frustoconical surface portion  39  which extends from the rearward end of the cylindrical opening  38  to the rearward end  35 . The interior surfaces  38  and  39  of the tip  16  are designed to mate with the exterior surface of the nozzle end  31  at the forward end of the mixer tube  12 . Preferably, these dimensions are such as to provide a relatively tight interference fit between the surfaces of elements  31  and  38 . In the preferred embodiment, the angle “C” which the frustoconical surface forms with the axis  13  matches the angle “A”. 
     With continuing reference to  FIGS. 4 and 5 , the exterior frustoconical surface portion  36  is provided with a plurality of grooves or flow channels  40  which extend from the rearward end  35  to the forward end  34 . As shown, these grooves or channels  40  extend from the rearward end  35  toward the forward end  34  in a generally spiral or helical pattern. The spiral angle, or the angle which each of the grooves  40  forms with a plane extending through the axis  13 , is less than 30 degrees, more preferably between about 5 degrees and 25 degrees and most preferably between about 10 degrees and 20 degrees. As shown best in  FIG. 5 , these grooves  40  extend from the rearward end  35  to the forward end  34  and form a recess  41  in the rearward end  35  and a recess  42  in the forward end  34 . The recess  42  in the forward end is shown in the enlarged view of  FIG. 6 . As shown, the recess  42 , and thus the groove  40 , includes a radial dimension “rd” and a circumferential distance “cd”. The radial dimension “rd” is measured in the radial direction relative to the axis  13 , while the circumferential dimension “cd” is measured in the circumferential direction relative to the axis  13 . 
     A feature of the preferred embodiment of the present invention is that the cross-sectional configuration of the recess  42  or the groove  40  as measured at the forward end  34  has a generally flat configuration in which the circumferential dimension “cd” is greater than the radial dimension “rd”. More preferably, the circumferential dimension “cd” is at least twice the radial dimension “rd” and most preferably the circumferential dimension “cd” is at least three times the radial dimension “rd”. In the embodiment shown in  FIGS. 4–6 , the cross-sectional configuration of the recess  42  formed by the groove  40  is a generally two-sided configuration having a radial edge portion  44  and a circumferential edge portion  45 . As shown in  FIG. 6 , the ends of the portions  44  and  45  intersect with one another and also with the frustoconical surface  36 . 
     In addition to the cross-sectional configuration of the recess  42  shown in  FIG. 6 , such configuration can take a number of other forms as shown in  FIG. 11 . Specifically, the recess  42  is shown along with two other possible configurations  46  and  48 . The recess  46  is shown as having two generally equal radial edges  49 , 49  in combination with a circumferential edge  50 , while the recess  48  is shown as having two radial edges  51 , 51  of unequal length in combination with a circumferential edge  52 . In all of these configurations, it is preferable for the recesses  42 , 46  and  48  to have a generally flat configuration with the circumferential dimensions being greater than the radial dimensions, more preferably at least about twice the radial dimensions, and most preferably at least about three times the radial dimensions. 
     The air atomizing cap  18  is shown best in  FIGS. 7 and 8 . The cap has a forward end or edge  54 , a rearward end  55  and an interior surface extending from the forward end  54  to the rearward end  55 . This interior surface includes a first frustoconical surface portion  56 , a second frustoconical surface portion  58  and a rearward, generally cylindrical surface portion  59 . As shown, the first frustoconical surface portion  56  extends from the forward end  54  rearwardly to a point  57  where it joins with the forward end of the second frustoconical surface portion  58 . The surface portion  59  extends forwardly from the rearward end  55  and joins with the rearward end of the surface portion  58 . 
     As shown best in  FIG. 7 , the angle “B” which the frustoconical surface portion  56  forms with the axis  13  is less than that of the frustoconical surface  58 . Preferably, the surface portion  56  has a frustoconical angle “B” matching that of the exterior frustoconical surface  36  of the mixer tip  16 . Accordingly, it is preferably at least about 5 degrees, more preferably at least about 10 degrees and most preferably about 15 to 25 degrees. 
     When the air atomizing cap  18  is assembled in operational position with the mixer tip  16  as shown in  FIGS. 2 and 3 , the interior frustoconical surface portion  56  engages and mates with a portion of the exterior frustoconical surface  36  to form a plurality of passageways  43  ( FIG. 3 ) defined by the grooves  40 . Preferably the length of the passageways  43  is no less than about 3/16 of an inch and preferably no less than the diametrical dimension of the surface portion  56  at the forward end  54 . Most preferably, the axial length of the surface portion  56  from the forward end  54  to the point  57 , relative to the cross-sectional configuration and size of the passageways  43  should be sufficient to create laminar flow within such passageways  43 . 
     Because the angle which the frustoconical surface portion  58  forms with the axis  13  is significantly larger than the angle “B”, the surface portion  58  and surface  59  are spaced outwardly from the corresponding area of the surface portion  36  of the tip  16  ( FIG. 4 ), thereby creating a flow area to provide atomizing fluid to the passageways  43 . 
     The rearward end  55  of the atomizing cap  18  is generally annular and is perpendicular to the axis  13 . When the device of the present invention is assembled, the surface  55  seats against the forward end of the air nozzle body  15  as described below. The exterior surface of the atomizing cap  18  is provided with a retaining shoulder  60  which mates with corresponding structure of the retaining nut  19  to retain the atomizing cap  18  in an assembled position relative to the air nozzle body  15  and thus the mixture body  11 . 
     The air nozzle body  15  which is shown generally in  FIG. 1  and in greater detail in  FIGS. 9 and 10  includes a generally cylindrical main body portion  61  having an inner surface  62  defining a generally hollow interior chamber  70 . The rearward end of the main body  61  is provided with a plurality of interior threads  64  to connect with the threads  25  at the forward end of the body  11 . A nipple  63  with external threads  65  extends forwardly from the main body  61  for connection with the retaining nut  19 . An atomizing fluid inlet port  66  is provided in the side of the main body portion  61 . The port  66  communicates with the interior chamber  70  and is provided with interior threads for connection to a source of pressurized atomizing air (not shown). For application of a single component material, the mixer tube  12  can be replaced by a material supply tube. 
     The retaining nut  19  ( FIG. 11 ) includes a plurality of interior threads  68  at its rearward end and a retaining shoulder  69  near its forward end. When assembled, the interior threads  68  are received by the exterior threads  65  of the nipple portion  63  and the shoulder  69  engages the retaining shoulder  60  of the atomizing cap  18 . Accordingly, the retaining nut retains the cap  18  and thus the tip  16  to the nozzle body  15  and thus the mixer body  11 . 
     When assembled in this manner as shown best in  FIG. 2 , an atomizing fluid chamber  70  is provided within the nozzle body  15  to provide atomizing fluid to the spiral passageways  43  ( FIG. 3 ) formed by the grooves  40  in combination with the inner frustoconical surface  56  of the cap  18 . When pressurized atomizing air is provided to the chamber  70 , this air exits the passageways  43  at the forward end  34  of the tip  16  in generally flat, converging and spiraling streams. 
     As application fluid or material is discharged through the nozzle tip  30  from a pressurized source, the flat, converging and spiraling streams of atomizing fluid contact the discharged application fluid stream and dispenses or atomizes the stream into tiny droplets. Although applicant does not wish to be bound by any particular theory, it is believed that because of the generally flat shape or configuration of the atomizing air flow streams as they exit the atomizing nozzle assembly, the application fluid stream is subjected to shear forces and thus provides more thorough and complete atomization, particularly for fluids which are highly viscous and/or exhibit a high tensile strength. Preferably, the circumferential dimension “cd” of the recesses  42  (and thus passageways  43 ) at the forward end of the tip  16  is greater than the radial dimension “rd”, more preferably twice as great and most preferably about three times as great. 
     A further embodiment of a spray head and mixer assembly is shown in  FIGS. 13 and 14 . In this embodiment, the mixer body  11  of  FIG. 1  is replaced by the pair of nuts  75  and  76  and the rubber O-ring retaining grommet  78 . As shown, the mixer tube  12  includes a rearward end similar to that of  FIG. 1  with a beveled seat portion  27  and rearward annular portion  29 . The rear nut  75  is a connection nut which is slipped onto the tube  12  at its forward end and includes an inner beveled surface  79  to seat against the beveled seat portion  27 . The nut  75  includes internal threads  80  for connection to a supply of pressurized application fluid (not shown). 
     The nut  76  is a retaining nut which includes a rearward cylindrical portion  81  having a diametrical dimension approximating or slightly larger than the exterior diameter of the tube  12 . Immediately forward of the portion  81  is an interior surface designed to seat against a retaining member in the form of the O-ring grommet  78 . The forward end of the nut  76  includes internal threads for connection to the air cap assembly  77 . 
     The O-ring grommet  78  is slipped onto the mixing tube  12  after the nuts  75  and  76  have been slipped on and preferably has an internal diameter slightly smaller than that of the tube  12 . When applied to the tube  12 , the grommet  78  has sufficient stiffness and there is sufficient friction between the grommet  78  and the tube  12  to retain the nut  76  when tightened against the air cap assembly  77 . If needed or desired, a second O-ring grommet or other retaining member can be provided. The grommet  78  or other retaining member is preferably selectively removable from the tube  12  and functions to retain the nut for the purpose intended. 
     The embodiment of  FIGS. 13 and 14  is provided with an air manifold or mixer tip  16  at the forward end  85  of the tube  12 . The tip  16  is the same as the tip  16  shown and described with respect to the embodiment of  FIG. 1  and is sized to fit over the end  85  so that the forwardmost end surface of the end  85  is substantially flush with the forwardmost end surface of the tip  16 . 
     The air cap assembly  77  includes inner conical surfaces  86  and  88  similar to the conical surfaces  56  and  58  of  FIG. 7 . Like the surfaces  56  and  58  of  FIG. 7 , the surfaces  86  and  88  cooperate with the outer surface of the mixer tip  16  to provide a plurality of atomizing air flow passages. The rearward end of the assembly  77  includes external threads  89  for connection to the retaining nut  76  as shown. An externally threaded top  90  is threadedly received by a port in the body of the assembly  77  to connect an air supply fitting  91 . The fitting  91  is designed for connection to a supply of atomizing air (not shown). 
     When connected with the mixer tube  12 , the nut  76  and the assembly  77  define an atomizing air chamber  92  to provide atomizing air to the passages between the tip  16  and the conical surfaces  86  and  88 . This embodiment provides a spray head construction in which the body  11  can be eliminated and in which the atomizing assembly comprised of the nut  76 , the assembly  77  and the tip  16  can be easily changed for cleaning or for replacement or the like. Further, all of the air atomizing components of the embodiment of  FIGS. 13 and 14  can be constructed of plastic and injection molded. The components can also be made of other materials such as light weight metals. 
     In addition to the air atomizing assembly of the preferred embodiment and related equipment illustrated in  FIGS. 1–14 , various other air atomizing embodiments and systems in accordance with the present invention are illustrated in  FIGS. 15–24 . In  FIGS. 15–24 , only the atomizing assembly (or a portion thereof in the form of the tip  16  and the cap  18 ) is illustrated, it being understood that such atomizing assemblies can be used with a mixer tube and assembly such as that illustrated in  FIGS. 1–14  above or with an application fluid supply tube or any other means currently known in the art or hereinafter known in the art for supplying pressurized application fluid to the atomizing assembly. 
     In the embodiment of  FIGS. 1–14 , the atomizing assembly included an inner atomizing tip with an outer generally frustoconical surface and an outer atomizing cap with a complimentary inner generally frustoconical surface. In such embodiment, a plurality of grooves were shown as being formed on the outer frustoconical surface of the atomizing tip which, when assembled with the cap, formed a plurality of atomizing fluid passageways or flow channels with a specific configuration, namely, passageways or channels which spiral and which have a flattened configuration with a circumferential dimension at least twice the radial dimension. 
     The present invention contemplates, however, that such grooves could be formed either in the outer frustoconical surface of the atomizing tip or the inner frustoconical surface of the atomizing cap and that the surfaces in which the grooves are formed could comprise configurations other than conical or frustoconical and that the grooves could be straight, spiraled or curved and could be of a variety of configurations. For example, the grooves that define the atomizing air channel could be straight, non-spiraled grooves and could be formed in surfaces that are not conical or frustoconical. Further, unlike the embodiment of  FIGS. 1–14  in which the grooves have a cross-sectional configuration such as those shown in  FIG. 12 , a variety of other cross-sectional configurations may be used as well. Specifically,  FIG. 26 , a figure similar to  FIG. 12 , shows a variety of such other configurations. These include a generally circular or semi-circular configuration  118 , a square configuration  119 , a triangular configuration  120 , or any other cross-sectional configuration that will result in atomizing the application fluid. 
       FIGS. 15 and 16  show an embodiment in which the plurality of grooves  95  are formed on the inner frustoconical surface of the cap  18 . Thus, when the cap  18  of  FIGS. 15 and 16  is assembled with the atomizing tip  16 , a plurality of passageways or flow channels  96  are formed by the grooves  95  in combination with the outer frustoconical surface of the tip  16 . 
     Further, although the preferred embodiment shows the outer and inner surfaces of the tip and cap as frustoconical, there is no requirement that such surfaces be limited to that shape. As described below with respect to  FIGS. 18–20 , such surfaces can form various shapes as long as the channels formed therein function to atomize the application fluid as desired. 
     Thus, a feature of the present invention can be characterized as comprising a first atomizing member having an outer surface portion and a second atomizing member having an inner surface portion of a size and configuration substantially matching that of the outer surface portion, with one of the inner and outer surface portions having a plurality of grooves extending from its rearward end toward its forward end to define passageways or flow channels when such surfaces are assembled into engagement with one another. 
     The embodiment of  FIG. 17  is similar to the embodiment of  FIGS. 15 and 16  in that the grooves  95  which form the flow channels  96  are formed in the inner surface portion of the cap  18 . Such embodiment, however, differs from the embodiments of  FIGS. 15 and 16  as well as the embodiments of  FIGS. 1–14  in that the atomizing tip or first atomizing member  98  is formed as an integral portion of the end of the mixing or fluid supply tube  12 . Thus, when the structure of the atomizing assembly in accordance with the present invention is described as having an inner or first atomizing member with an outer surface, such member can be a separate and distinct element such as the atomizing tip  16  shown in the embodiments of  FIGS. 1–16  or can be an element  98  which is integrally formed with the mixing tube  12  such as shown in  FIGS. 17  or integrally formed with a supply tube or other means for supplying pressurized application fluid to an outlet nozzle. If desired, the cap  18  of  FIG. 17  can be a snap-on cap which is injection molded and which is retained relative to the member  98  by an “O” ring or other retaining means. 
     In the embodiment of  FIGS. 1–14 , the outer surface of the atomizing tip  16  and the inner surface of the atomizing cap  18  are described as being generally frustoconical surfaces. While such a surface configuration is preferred, it is contemplated that various other surface configurations could be utilized as well. For example, the outer and inner surfaces of the atomizing tip and cap, respectively, could converge inwardly toward the nozzle opening and have a generally elliptical or other elongated cross-section. For example, as shown in the embodiment of  FIGS. 18 ,  19  and  20 , the outer and inner surfaces of the tip  16  and cap  18  could extend rearwardly from a generally elongated nozzle opening  99 . In the embodiments of  FIGS. 18–20 , like the embodiments of  FIGS. 15–17 , the inner surface of the cap  18  is provided with a plurality of grooves to form the flow passages  100 , although such grooves could be formed in the outer surface of the tip  16 , if desired. Also, although  FIG. 20  shows the supply tube  12  as curving inwardly as it extends rearwardly from the opening  99 , such tube  12  could extend rearwardly in a substantially straight line. With the elongated nozzle opening  99 , the embodiment of  FIGS. 18–20  is particularly applicable for achieving relatively wide spray or application patterns. 
     The flow channels  100  of  FIGS. 18–20  are preferably flattened channels as described above. Although each of the channels  100  can lie in a plane extending through the nozzle opening  99 , the channels  100  are preferably sloped relative to such a plane. In the preferred embodiment, the set of channels  100  on one side of the nozzle opening  99  slope in one direction and the set of channels  100  on the other side of the nozzle opening slope in the opposite direction. 
     In general, the shape of the outer and inner surfaces of the first and second atomizing members in accordance with the present invention can assume a variety of shapes and configurations. Preferably, however, such inner and outer surfaces should preferably have complimentary dimensions and configurations for a length at least equal to the diameter of the nozzle opening. Further, such inner and outer surfaces should preferably have a cross-sectional configuration similar to the shape of the orifice. Specifically, if the orifice is elongated, the cross-sectional configuration of the inner and the outer surfaces should be elongated. 
       FIGS. 21 ,  22 ,  23  and  24  disclose means in combination with an air atomizing assembly, for breaking up the flow stream of the application fluid and thus assisting in the atomization of the application fluid to facilitate larger flow rates and, in some cases, to reduce the application pressure of the application fluid. 
     In certain spray application environments, the flow stream of the application fluid is relatively large due to the nature of the application fluid itself or the desire to increase the efficiency of the application process, among others. Such large flow streams, particularly flow streams of high viscosity fluids or high surface tension fluids such as epoxies, urethanes, polyureas and other adhesives, are difficult to spray or break up with atomizing air alone and often require relatively large application pressures. In many spray environments, this necessarily limits the maximum flow rate of fluid that can be satisfactorily atomized and applied and the equipment with which such fluid can be satisfactorily applied. 
     In the embodiment of  FIGS. 21 and 22 , a relatively large nozzle orifice  101  ( FIG. 22 ) is provided with a flow diverter or diverter orifice  102 . The diverter orifice  102  is essentially a wall or another obstruction in the flow nozzle, or upstream of the flow nozzle, which causes the flow stream to break up into a plurality of smaller flow streams as it leaves the nozzle opening. In  FIGS. 21 and 22 , the diverter  102  includes a plurality of smaller orifices  104 . When pressurized fluid is introduced into the flow tube  12 , the diverter  102  causes the fluid in the orifice nozzle  101  to flow through the plurality of orifices  104 . Such diverter, or other obstruction can be located at the nozzle opening as shown or can be anywhere upstream from the nozzle opening. This breaks up the single flow of material within the orifice  101  into smaller multiple streams of material through the orifices  104 . This improves the ability of the atomizing air to further break up and atomize the material in the multiple flow streams, thus enabling application of greater flow rates with the same atomizing air and, in some cases, lower application pressures. 
       FIGS. 24 and 23  show a further embodiment for breaking up a relatively large application fluid flow stream to facilitate more efficient atomization. In  FIGS. 23 and 24 , an air stream is directed to a point within the application fluid flow stream itself. This air stream may be an independent air stream or, as shown in the preferred embodiment, be part of the atomizing air. Further, the air stream may be atmospheric or any other gas such as nitrogen (N 2 ), or carbon dioxide (CO 2 ) or any other fluid which will function to break up the application fluid stream and/or reduce its viscosity as it flows through the supply tube  12 . 
     In  FIGS. 23 and 24 , the preferred air stream is a portion of the atomizing air flow which is directed from the atomizing air chamber or source into the central portion of the application fluid stream  107  via the conduit or flow tube  105 . During operation, this air stream flows through the tube  105  and into the central portion of the fluid stream  107 . This tends to break up or disperse the flow stream  107 , thereby facilitating easier and more efficient atomization with the atomizing air. This in turn improves the flow rate of the application fluid and thus increases the application efficiency with substantially the same amount of atomizing air. This also results, in some cases, in a reduction of the application fluid pressure required to apply the application fluid at a specific flow rate. 
     Thus, a further feature of the present invention includes means in the form of a flow breakup member positioned within the application flow stream and preferably at or near the orifice opening, but anywhere upstream of such opening, for breaking up the flow stream into smaller, more easily atomized flow streams. In some cases, particularly with the embodiment of  FIGS. 23 and 24 , the tube  105  can be positioned significantly upstream from the nozzle opening such as at or near the source of pressurized application fluid. Preferably the air or other fluid flow introduced through the tube  105  is introduced in the downstream direction at a point upstream from the nozzle opening. 
     In  FIGS. 21 and 22 , this break up member is the flow diverter  102  or other flow breakup structure. In  FIGS. 24 and 25 , this member comprises the flow tube  105  for introducing a flow stream of gas or other fluid upstream from the nozzle opening. This gas or fluid may be a portion of the atomizing air or may be from an independent source. 
     The method aspect of the present invention relates to a method of utilizing the atomizing air as a vehicle for introducing a curing agent, catalyst or other component into the application fluid or to otherwise condition the application fluid. 
     Many application fluids, and in particular adhesives and other high viscosity and high surface tension materials, are moisture cured. For example, most one-part silicon adhesives and most one-part urethane adhesives are moisture cured. This means that the presence of moisture in contact with the application fluid initiates the curing process. In the current art, it is common to apply the application fluid to a substrate and then apply moisture to the surface thereof to initiate the curing process. This has drawbacks, however, in that the moisture is not thoroughly mixed with the applied fluid and a skin comprised of cured application fluid tends to form on the surface of the applied fluid. However, by introducing moisture into the atomizing air, such moisture becomes thoroughly mixed with the application fluid, resulting in more complete and uniform curing. Introduction of moisture into the atomizing air also eliminates the extra step of applying the moisture to the substrate after application of the fluid. 
     Further, some resin systems require a curing catalyst or agent other than moisture to initiate the curing process. In accordance with the present invention, such curing catalysts or other agents can also be introduced via the atomizing air stream. This thoroughly mixes the catalyst or other agent with the application fluid and initiates the curing process immediately upon application. 
     Still further, for two-part application fluid systems, the atomizing air stream can be used to introduce and mix one part or component of the system with the other part or component of the system which is applied through the nozzle outlet. 
     A still further method in accordance with the present invention is to utilize the atomizing air to condition the application fluid. For example, in some application fluid systems, the viscosity of the application fluid and the cure rate of the application fluid can be controlled by controlling the temperature of the application fluid. This is commonly done by providing heating and/or cooling means in the application fluid supply line to heat the fluid to the desired temperature. In accordance with the present invention, however, the atomizing air is heated or cooled. This results in corresponding heating or cooling of the application fluid during atomization, thereby providing a means for controlling the viscosity and/or cure rate of the application fluid. 
     The system for performing the method aspect of the present invention described above is shown in  FIG. 25 . Such system includes a source of pressurized application fluid  108  for providing pressurized application fluid through the line  109  to the delivery means  110 . The delivery means  110  includes a spray and atomizing nozzle  111  which may be similar to that described above or which may comprise any conventional spray or delivery air atomizing means currently or hereinafter known in the art. The system also includes a source of pressurized atomizing air or other atomizing gas or fluid  112  which is delivered via the line  116  to the atomizing means  111 . The system also includes one or more supply vessels or other means  114  for selectively supplying secondary material to the atomizing air in the line  116  for ultimate delivery to the nozzle assembly  111  and mixing with the application fluid. As described above, such secondary component may include water or other fluid for introducing moisture into the line  116  for a moisture cured system. Such secondary component may also include other curing agents or catalysts or may also include a second component in a two-component application fluid system. Such moisture or other curing agent or catalyst is preferably introduced in a quantity sufficient to fully, or at least partially, cure the application fluid delivered through the nozzle orifice. 
     Such system also includes an inline heater/cooler means  115  for selectively heating or cooling the atomizing gas or fluid in the line  116  to a desired temperature. Thus, via the heater/cooler means  115 , the atomizing gas or fluid can be conditioned to the desired temperature to thereby control the viscosity and/or the rate of cure of the application fluid. Appropriate control means  113  may be included in the system of  FIG. 25  to control the flow of application fluid, the flow of atomizing gas or fluid, the selected flow of one or more secondary components from the supplies  114  and the selected temperature of the atomizing gas or fluid via the heater/cooling means  115 . 
     Although the description of the preferred embodiment has been quite specific, it is contemplated that various modifications could be made without deviating from the spirit of the present invention. Accordingly, it is intended that the scope of the present application be dictated by the appended claims rather than by the description of the preferred embodiment.