Abstract:
A fan nozzle for cleaning a surface with an abrasive blast media is constructed of a longitudinal body having an axial pathway through which the media is passed under pressure for release from a substantially rectangular cross-sectional outlet to release the media in a substantially flat, wide path. A first transition zone provides a conversion in the axial pathway from the inlet cross-section to the substantially rectangular cross-section of the outlet opening. A second transition or convergence zone first reduces and then expands the cross-section of the axial pathway for providing a Venturii acceleration of the media as it passes through the nozzle. The transition zone and the convergence zone may be coexistent along a portion of the axial pathway.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of applications U.S. Ser. No. 12/012,419 and U.S. Ser. No. 12/711,920 for Fan Nozzle, filed on Feb. 1, 2008 and Feb. 24, 2010, respectively. These prior applications are incorporated by reference herein and priority is claimed. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The subject invention relates generally to nozzles for releasing abrasive filedia under pressure and is specifically directed to a fan nozzle for releasing the abrasive media in a wide, flat path. 
         [0004]    2. Discussion of the Prior Art 
         [0005]    Fan nozzles are relatively well known in the industry and are used to release an abrasive media under pressure in a substantially wide, flat path instead of in a circular pattern as with nozzles with round openings. Such nozzles are particularly convenient when the abrasive media is being used to clean a large surface and it is desirable to pass the nozzle over the surface in sweeping motions. 
         [0006]    Typically, such nozzles are adapted to be connected to a common source of pressurized abrasive media, which normally is a coupler on the end of a hose of circular cross-section. The circular cross-section of the inlet end of the nozzle is then in communication with a convergence zone wherein the cross-section of the nozzle is less than the cross-section of the inlet of the nozzle or the outlet of the pressure source. When the media passes through the convergence zone the velocity of the flowing media accelerates as the media is introduced into the larger cross-section of the rectangular outlet of the nozzle, caused by the Venturii effect of passing the media through the reducing and then expanding zones. 
         [0007]    Such nozzles have been around for many years. Some typical examples are shown and described in U.S. Pat. Nos. Re. 34,584; 5,704,825 and 6,626,738. Each of these patents use a Venturii-type convergence zone for reducing and then expanding the cross-sectional area of the nozzle to cause acceleration of the media as it is expelled through the nozzle outlet. 
         [0008]    While such nozzles may be useful for the intended purpose of providing a pressurized blast media in a flat path for cleaning surfaces, they all have a common drawback. Specifically, the prior art nozzles provide for an immediate transition from a generally circular inlet cross-section to a generally rectangular outlet cross-section. This creates wear points at the transition, as well as turbulence. In addition, such a configuration creates hotspots in the media flow as the media is released from the nozzle. 
         [0009]    With specific reference to U.S. Pat. No. Re. 34,854, it will be noted that the convergence section has an inlet end that is of a rectangular cross-section, such inlet end being adapted to connect directly to the coupler of circular-cross section. This provides for an immediate transition from a circular source to a rectangular nozzle pathway, creating a wear point at the transition as well as generating turbulence in the blow. The Venturii convergence zone is all of rectangular cross-section. 
         [0010]    The blast nozzle of U.S. Pat. No. 5,704,825 also shows an immediate transition from a circular inlet to a rectangular convergence zone and has the same drawbacks as the nozzle of U.S. Pat. No. Re. 34,854. 
         [0011]    The fan nozzle shown in U.S. Pat. No. 6,626,738 shows a circular cross-section Venturii in communication with the inlet end of the nozzle. Specifically, the inlet is circular and transitions into an ellipse prior to an expanding rectangular fan nozzle outlet. While an improvement over earlier designs, this still does not overcome the hot spots typically present in a fan nozzle. 
       SUMMARY OF THE INVENTION 
       [0012]    The subject invention is a fan nozzle for cleaning a surface with an abrasive blast media. The nozzle is constructed of a longitudinal body having an axial pathway through which the media is passed under pressure for release from a substantially rectangular cross-sectional outlet to release the media in a substantially flat, wide path. Within the body of the nozzle and along its axial pathway there is a transition zone providing a conversion in the axial pathway from the inlet circular cross-section to the substantially rectangular cross-section of the outlet opening. 
         [0013]    There is also a second transition zone or convergence zone within the body of the nozzle and along the axial pathway intermediately of the inlet end and the outlet end for first reducing and then expanding the cross-section of the axial pathway within the longitudinal body for providing a Venturii acceleration of the media as it passes through the nozzle. In the preferred embodiment: of the invention the transition zone and the convergence zone are coexistent along a portion of the axial pathway. 
         [0014]    The convergence zone may reduce the cross-sectional area of the axial pathway in a plane parallel to the release path. Alternatively, the convergence zone may reduce the cross-sectional area in a plane perpendicular to the release path. In addition, where desired, the convergence zone may reduce the cross-sectional area of the axial pathway in planes both parallel to the release path and perpendicular to the release path. 
         [0015]    In the preferred embodiment of the invention the nozzle comprising the longitudinal body, including the inlet end, the outlet end and the transition zone and the convergence zone may be of unitary construction. 
         [0016]    By providing the transition zone in. accordance with the subject invention the media flow is converted from a flow of circular cross-section to a flow of rectangular cross-section over a longitudinal path. This provides a smooth transition and minimizes both the turbulence and wear. In addition, by providing a smooth transition, the abrasive particles are more evenly distributed throughout the flow area cross-section whereby the hot spots in the media flow outlet are substantially reduced. 
         [0017]    The transition zone is used in combination with a convergence zone to both convert the cross-sectional pattern of the flow and accelerate the flow to provide improved fan nozzle performance with a desirable wide, flat: path with a minimum of hot spots. This permits more even flow of the media and more even cleaning or preparation of the surface being treated. 
         [0018]    In the preferred embodiment of the invention, the convergence zone and the transition zone are coexistent along the longitudinal media flow path. However, it is not necessary that the zones be coexistent. 
         [0019]    Also, the subject invention incorporates a convergence zone which can intersect the flow path in a plane parallel to the fan nozzle outlet, or a plane perpendicular to the fan nozzle outlet, or both parallel and perpendicular depending on preference. 
         [0020]    The fan nozzle of the subject: invention produces a desirable wide, flat media flow with a minimum of hotspots making it useful for a large variety of applications. The features of the invention will be made more apparent by reference to the accompanying drawings and detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of the fan nozzle of the subject invention. 
           [0022]      FIG. 2  is a diagrammatic view of the axial pathway of the nozzle, diagrammatically illustrating the relationships of the cross-sectional areas of the interior of the nozzle throughout its length. 
           [0023]      FIG. 3  is a slice view of the nozzle looking from the inlet toward the outlet. 
           [0024]      FIG. 4  is a slice view of the nozzle, looking down on the nozzle in a plane perpendicular to the plane of the fan expansion section. 
           [0025]      FIG. 5  is a sectional view taken along line  5 - 5  of the slice view of  FIG. 3 . 
           [0026]      FIG. 6  is a cross-sectional view of the nozzle taken along line  6 - 6  of  FIG. 1 . 
           [0027]      FIG. 7  is a top view of the nozzle showing in phantom the axial passageway. 
           [0028]      FIG. 8  is a top view of an alternative embodiment of the nozzle, showing in phantom a modified axial passageway. 
           [0029]      FIG. 9  is a diagram showing the flow through a nozzle in accordance with the subject: invention. 
           [0030]      FIG. 10  is a diagram contrasting the flow through a prior art nozzle configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    With specific reference to  FIG. 1 , the fan nozzle of the subject invention comprises a longitudinal body  20 . The fan nozzle is divided into three main sections, the inlet section  22 , the transition section  24  and the expansion section  26 . A cross-sectional view of the nozzle, taken along line  6 - 6  of  FIG. 1  is shown in  FIG. 6 . The inlet  28  of the nozzle is adapted to be coupled to a source of pressurized media and is typically of a generally circular cross-section, but may be modified, as at  30 , to receive a connector on the source (not shown). Inwardly of the inlet  28 , the inlet section  22  is of a rectangular cross-section, as shown in  FIGS. 2-5 , for distributing the pressurized air or other fluid and the abrasive throughout the full cross-sectional area of the nozzle. Specifically, the inlet end  28  of the nozzle provides a transition from the circular connector at  28   a  to a rectangular cross-section at  31 , with the remainder  33  of the inlet section being of rectangular cross-section. An axial pathway extends the entire length of the nozzle assembly and connects the outlet  32  with the inlet  28 . 
         [0032]    The convergence transition section  24  of the nozzle flows from the inlet section  22  into a throat  25  which is the inlet to the expansion section  26 . The convergence transition section provides a reduction in area of the rectangular cross-sectional flow, path in the inlet section. This provides a Venturii effect for accelerating the fluid/abrasive mix. The throat determines airflow consumption. As shown in  FIGS. 2-5 , the entire convergence transition section is of continuously reducing, rectangular cross-section. The expansion section  26 , also of rectangular cross-section, then “fans out” or expands in one plane and terminates in a rectangular, flat outlet  32 . This provides full divergence of the fluid/media mix across the entire cross-sectional area of the outlet  32  for dispersing the mix onto a target object. 
         [0033]    As better shown in  FIG. 2 , the inlet  28  is of a cross-section adapted to fit the source of the fluid/media flow, as shown at  28   a.  This is then converted to a generally rectangular cross-sectional area as shown at  22   a,  which extends the entire length of the inlet section  22 , as indicated at  22   a  and  22   b.  The cross-sectional area is continuously reduced in the convergence transition section  24 , as indicated at  24   a,    24   b  and  25   a,  with the final cross-section  25   a  defining the nozzle throat for controlling flow. Specifically, the cross-sectional areas  22   a  and  22   b  are substantially the same for the entire length of the inlet section  22 . Cross-sectional areas  24   a,    24   b  and through to  25   a  are continuously reducing. Cross-sectional areas  26   a,    26   b  and through  26   c  in the nozzle expansion zone are continuously increasing. The diagrammatic cross-sections above the fan nozzle illustration show the cross-sectional area configuration including circular inlet  28   a,  the transition to rectangular cross-section at  22   a,  the transition section  24 , the throat  25  and the expansion section  26  terminating at the outlet  32 . The sectional area  25   a  defines the controlling throat  25 . The cross-sectional area is then expanded in the expansion section  26 , as indicated at  26   a,    26   b  and  26   c.    
         [0034]    A longitudinal slice through the nozzle  20  and looking from the inlet opening  28  toward the outlet opening  32  is shown in  FIG. 3 . This clearly shows the relationship between the various junctions of ‘the nozzle, with the circular-to-rectangular transition present at  28   a,  the rectangular cross-sectional inlet section  22 , the converging transition section  24  and throat  25  terminating in the expansion section  26 . This configuration permits a continuous, smooth flow of the media through the nozzle without any abrupt transition points, reducing turbulence and minimizing wear. It also permits the media flow to reshape itself without creating hotspots due to interruption in flow or increased resistance to flow’ in specific areas. Another slice view, looking down on the nozzle, is shown  FIG. 4 . 
         [0035]      FIG. 5  is an end view of the nozzle taken at line  5 - 5  of  FIG. 3  and looking in the direction from the inlet  28  toward the outlet  32 . This shows the relationship between the inlet  28 , the transition  22   a,  the inlet section  22 , the convergence transition section  24 , the throat  25 , the expansion section  26  and the outlet  32 . 
         [0036]    As better shown in  FIGS. 6 and 7 , the convergence transition section  24  begins with the full cross-sectional area  50  at the junction between the inlet section  22  and the convergence section  24 . The cross-sectional area is continually reduced by the tapered wall  52  of the body, as indicated in  FIGS. 1 ,  6  and  7 , terminating at the throat  25 . Then beginning at the throat outlet  54  the cross-section continually increases in a plane substantially perpendicular to the converging plane of the transition section, as indicated by the outward fanning or tapered wall  56  of the nozzle. This creates a Venturii effect acceleration of the media as it flows through the nozzle and is expelled through outlet  32 . 
         [0037]    The transition section of the embodiment of  FIGS. 1 ,  6  and  7  is in a single plane running parallel to the opening  32  in nozzle  26 . An alternative embodiment is shown in  FIG. 8 . In this configuration, the convergence section  48  is perpendicular to the plane of the nozzle  26 . However, in function it operates in the same manner as the configuration of  FIGS. 1 and 6 . Namely, the cross-section of the convergence section is the same as the inlet section at junction  60 , and reduced by the tapered wall  62  to the junction  64  between the convergence section  58  and the nozzle  26 . The cross-section then expands in the tapered fan nozzle section  26 , again creating a Venturii effect acceleration of media toward the nozzle outlet  32 . 
         [0038]    The two configurations of the convergence section may be used independently of one another, or in combination. Also, while the convergence section(s) and the transition section  24  are shown as longitudinally separated in the illustrated embodiments, it should be readily understood by those who are skilled in the arts that these two sections could be coexistent along the flow path of the nozzle. By placing them in a coexistent position, the nozzle can be of a more compact design. 
         [0039]    The flow path of a nozzle in accordance with the present invention is graphically shown in  FIG. 9 . As can be seen, once the media flow enters the nozzle  26  at the transition/nozzle junction  44 , all of flow has been smoothly converted into a rectangular cross-section and is confined in the shaded area  70 . Then, because of the Venturii effect of the convergence zone, the flow only has to expand and accelerate outwardly as indicated by arrows  72  and  74 . 
         [0040]    This is to be contrasted with the prior art designs, as graphically illustrated in  FIG. 10 . In these configurations, there is an abrupt change in shape at the junction between the inlet section  100  and the rectangular nozzle section  102 . This is true even when a Venturii accelerator is used and the cross-section is reduced as indicated at:  104 . This results in some of the flow being trapped at the end of the convergence section when the convergence section is of circular cross-section, as indicated at  106  and  108 . The media flow then must travel in a direction perpendicular to the flow outwardly into the nozzle, as indicated at  110  and  112 . This results in turbulence, a wear point in the nozzle and hotspots in the flow as more of the media volume is in the areas of the arrows  110  and  112  and less of the media volume is in the area of the outer arrows  114  and  116 . 
         [0041]    The transition section of the nozzle of the subject invention minimizes turbulence, reduces wear and provides for a more even flow. When used in combination with a convergence section, the fan nozzle of the subject invention provides a smooth, wide, flat flow of media with a minimum of hot spots. While certain features and embodiments of the invention have been described in detail herein, it should be understood that the invention includes all modifications and enhancements within the scope and spirit of the following claims.