Abstract:
A rotary spray head for atomizing and dispersing fluidized coating material within a bearing stream. The rotary spray head has a plurality of elongated contoured material dispersing portals positioned to define multiple overlapping product stream flow across a diffuser surface imparting translateral product stream homogenation and adaptive proportional edge shear for an improved coating dispersal pattern.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to material atomizers, specifically to improved spray head for dispensing coating materials used in electrostatic painting. 
     2. Description of Prior Art 
     Prior art rotating heads for atomizing and dispensing paint in the electrostatic power painting industry have relied on a variety of head and nozzle configurations. See for example U.S. Pat. Nos. 5,326,598, 5,353,995, 5,368,237, 5,632,448, 5,865,380 and 5,922,131. 
     U.S. Pat. No. 5,326,598 is directed to an electro-spray coating apparatus and process utilizing precise control of filament and misgeneration. The device applies voltage to the liquid forced to have a single continuous and substantially continuous radius or curvature around a shaping structure so as to produce a series of filaments which are spatially and temporarily fixed. The number of filaments being defined can be varied by adjustment of applied voltage with the filaments breaking into uniform mists of charged droplets and are driven towards the substrate by electric fields to produce a coating. 
     U.S. Pat. No. 5,353,995 claims a rotary ionizing head for electrostatic application of air powder mixtures on objects fused by heat. An ionizer head is rotated by a turbine having a deflector incorporated constituting a charging electrode. 
     U.S. Pat. No. 5,368,237 illustrates an improved spray nozzle for powder coating guns which has dual intersecting slot configurations so as under rotation to change the effective width of the coating being applied therethrough. 
     U.S. Pat. No. 5,632,448 shows a rotating power applicator for atomizing and dispensing powder utilizing a fluidized powered bed to entrain the powder fluidized in a bearing airstream and dispense same having a somewhat bell shaped interior. 
     U.S. Pat. No. 5,865,380 for a rotary atomizing electrostatic coating device having a plurality of discharge electrodes defining a band form pattern which extends outwardly along the rear side of the spray head&#39;s main body. A plurality of discharge electrodes rotate together with the spray head in the main body and charge current in the front side direction of the axis of rotation of the spray head is made uniform and increased by enhancing the painting efficiency. 
     Finally, in U.S. Pat. No. 5,922,131 an electrostatic power spray coating apparatus is disclosed with a rotary spray orifice of a slot configuration to impart a flat shape to an atomized material to be dispensed therethrough. 
     SUMMARY OF THE INVENTION 
     An improved rotary spray head to apply atomized fluid coating material in an electrostatic application process. The spray head has a plurality of annularly spaced dispensing openings of elongated equilateral longitudinal dimension, each defining an independent spray pattern in overlapping relation to one another imparted onto a dispersion disk surface with an improved material flow impingement area therewithin. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a section on lines  1 - 1  of  FIG. 5 . 
         FIG. 2  is a side elevational exploded assembly view of the spray head of the invention. 
         FIG. 3  is a bottom plan view of the assembly. 
         FIG. 4  is a top plan view of the assembly with portions broken away and material spray patterns depicted graphically thereon. 
         FIG. 5  is an enlarged top plan view with portions broken away of the spray head aperture dispensing configurations. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 and 2  of the drawings, a rotary spray head assembly  10  can be seen used for the application of material coating fluids in an electrostatic painting system. The spray head assembly  10  has a main support drive and distribution body member  11  with a bowl shaped deflector top surface  12  terminating at a sharp tapered edge  13  thereabout. The body member  11  has a central annular receiving opening at  14  therein with an annular recess cap flange  15  formed in its oppositely disposed surface with a plurality of threaded bores  16  positioned therewithin define mounting surface  17  thereabout to receive corresponding threaded fasteners F as will be described in greater detail hereinafter. 
     An annular material dispersing head  18 , also seen in  FIG. 4  of the drawings, has an apertured conical center portion  19  with an extending mounting hub portion  20  aligned therewith. A tapered depending annular flange wall  21  extends inwardly from a contoured perimeter edge  22 , best seen in  FIG. 1  of the drawings. 
     The hub portion  20  defines a center mount shaft receiving opening  23  therewithin having a tapered interior surface at  23 A. The receiving opening  21  is in axial alignment with the aperture at  19 A in the conical center portion  19  which is of a proportionally increased diameter and is internally threaded at  19 B as will be well understood by those skilled in the art. 
     A plurality of radially spaced elongated material ejection dispersal openings  24  are formed within the depending annular flange wall  21 . Each of the ejection dispersal openings  24 , as best seen in  FIGS. 4 and 5  of the drawings, is of an elongated slot-like configuration with oppositely opposing angularly disposed sidewalls  24 A and  24 B. The angular inclination of the respective sidewalls  24 A and  24 B indicated by the broken extension lines  25  in  FIG. 6  of the drawings provide in combination with the proportional length to the height ratio of approximately two and a half to one are critical to the dispersion pattern DP imparted during operation in which the spray head is spun at relatively high revolutions per minute to afford the significant centrifugal force required to propel the material out through the respective ejection dispersal openings  24  as graphically illustrated in  FIGS. 4 and 5  of the drawings. The material dispersal head  18  can be seen as assembled within the annular opening  14  of the body member  11  with a portion cut-away illustrated therefore graphically the radial pattern of the static dispersal spray pattern at DP shown in broken lines radiating outward from each of the spaced adjacent ejection dispersal openings  24 . 
       FIG. 6  of the drawings is an enlarged portion of the spray head  18  broken away to illustrate the angular orientation of the walls  24 A and  24 B, of each apertured spray opening  24  and their respective contoured end wall curvilinear surfaces also seen in  FIGS. 1 and 2  of the drawings. 
     The deflector top surface  12  has an annular groove  26  therewithin, spaced approximately one-quarter the distance inwardly of the surface  12  at from the tapered edge  13 . The groove  26  is positioned so as to blend the respective multiple cross spray patterns DP of material as they emanate outwardly across the top surface  12  as hereinbefore described. Once the ejected material impinges the groove  26 , a continuous even sheeting action is achieved on the remainder of the surface  12  thereafter and is then released from the tapered edge  13  of the surface disk by a “sheer treatment” at  27  consisting of an annularly ribbed surface well known and used within the art. 
     It will be evident that given the rotation of the spray head assembly  10 , the actual material pattern DP as depicted are implicitly curved during operation as they are produced (not shown). 
     Referring back to  FIGS. 1 and 2  of the drawings, an assembly disk cap  28  can be seen having a central opening at  28 A with a collar flange  28 B thereabout. A corresponding annularly recessed area  29  extends therefrom as best seen in  FIG. 4  of the drawings. A continuous gasket receiving channel  30  is formed inwardly from the perimeter edge thereof defining a mounting surface engagement at  31  with a plurality of annularly spaced fastener receiving apertures  32  therewithin that align with the hereinafter described threaded bores  16 . 
     As to the assembly of the spray head  10  as illustrated in exploded assembly view in  FIG. 2  of the drawings, the dispersal head  18  as hereinbefore described is thermally press fitted within the body member  11 &#39;s receiving opening so that the corresponding ejection dispersal openings  24  are exposed against the top deflector surface  12 . The assembled cap disk  28  is fitted within the mounting cap recess against the cap mounting surface  31  as hereinbefore described. The assembled cap disk  28  so fitted defines a material receiving chamber  32  about the corresponding hub into which coating material M is supplied during functional rotation of the spray head assembly  10  and is forced out through the ejection dispersal openings  24  by centrifugal force, as noted. 
     It will be seen that applicant&#39;s rotary spray head assembly  10  where the application of material coating fluid in an electrostatic painting system provides the unique combination of enhanced material dispersal patterns DP which provide selective interference therebetween onto the dispersal disk surface  12  having the unique impingement groove  26  therein so as to provide a homogenous sheeting pattern of coating material enhancing the effectiveness thereof and imparting additional benefit by reduced product material M usage afforded by improved product material cleaning proficiency within the head. 
     It will thus be seen that a unique and novel rotary spray head assembly has been illustrated and described and it will be evident to those skilled in the art that various changes and modifications may be made thereto without departing from the spirit of the invention.