Abstract:
A spraying system is provided including a spray gun and a spray nozzle. The spray gun has a discharge end. A locating pin is arranged on the discharge end of the spray gun. The spray nozzle is selectively mountable on the discharge end of the spray gun. The spray nozzle has a discharge orifice configured to produce a asymmetrically distributed fluid discharge pattern wherein the location of maximum fluid discharge is offset from the center of the fluid discharge pattern. The spray nozzle has an alignment notch extending along an outer surface of the spray nozzle. The locating pin is arranged on the spray gun and the alignment notch is arranged on the spray nozzle such that when the spray nozzle is mounted on the discharge end of the spray gun in a predetermined orientation the locating pin extends into the alignment slot.

Description:
FIELD OF THE INVENTION 
   This invention pertains to spray nozzles and more particularly to spray nozzles which produce an asymmetrical distribution of the fluid discharge. 
   BACKGROUND OF THE INVENTION 
   In order to protect substances such as food and beverages from contamination, a coating is typically applied to the inside surfaces of containers in which such substances are stored. This coating prevents the contents of the container from coming into direct contact with the bare metal or plastic interior surfaces of the container. With standard cylindrical containers or cans, this coating is generally applied to the interior of the container before the top is affixed through the use of a spray nozzle which is arranged to discharge through the open end of the container. As the coating is being discharged from the nozzle, the container is rotated about its longitudinal axis so as to ensure that all of the interior surfaces are coated. 
   The coating material used on the inside surfaces of the containers represents one of the most significant costs associated with a container manufacturing operation. To help achieve an even coating, the coating material is generally applied using spray nozzles that are configured to produce an asymmetrical distribution of the fluid discharge. In particular, the nozzles generally produce a fan-shaped discharge pattern with a maximum amount of fluid being discharged at a point offset from the center of the spray pattern and with the level or amount of discharge tapering from the location of maximum discharge to either end of the spray pattern. These nozzles are arranged at an angle relative to the longitudinal axis of the container so that the heaviest portion of the discharge is directed towards the far, closed end of the container. Thus, the asymmetrical distribution helps compensate for the greater distance the coating material must travel to reach the closed end of the container and, in turn, the greater surface area of the interior of the container that this portion of the discharge pattern must cover. 
   Because of the asymmetrical distribution of the fluid discharge, the spray nozzles must be arranged in a specific orientation relative to the containers to achieve the desired even coating of the interior of the containers. If the orientation of the spray nozzles is incorrect, the containers will not be properly coated. A container coating operation typically is highly automated. Thus, when one or more of the spray nozzles applying the coating is installed incorrectly, a significant amount of time may elapse before the problem is discovered. Because a container coating operation also runs at a very high speed, thousands of containers may be coated improperly during this time. Once the alignment problem with the spray nozzles is corrected, the defective containers then have to be collected and recoated. Obviously, this is an expensive and time consuming process. 
   Currently, the standard practice for indicating the proper alignment of the spray nozzle is to place an arrow on the body of the nozzle. However, in a container coating operation, a build-up of the container coating material can quickly form on the spray nozzles. This build-up can obscure the arrow on the nozzle body making it difficult to determine if the nozzle is installed properly. 
   BRIEF SUMMARY OF THE INVENTION 
   A spray nozzle is provided which includes a nozzle body and a spray tip. The spray tip has a discharge orifice configured to produce a asymmetrically distributed fluid discharge pattern wherein the location of maximum fluid discharge is offset from the center of the fluid discharge pattern. The nozzle body includes an alignment notch extending in a longitudinal direction of the spray nozzle along an outer surface of the nozzle body. The alignment notch is arranged in a predetermined orientation relative to the discharge orifice. 
   A spraying system is also provided including a spray gun and a spray nozzle. The spray gun has a discharge end. A locating pin is arranged on the discharge end of the spray gun. The spray nozzle is selectively mountable on the discharge end of the spray gun. The spray nozzle has a discharge orifice configured to produce a asymmetrically distributed fluid discharge pattern wherein the location of maximum fluid discharge is offset from the center of the fluid discharge pattern. The spray nozzle has an alignment notch extending along an outer surface of the spray nozzle. The locating pin is arranged on the spray gun and the alignment notch is arranged on the spray nozzle such that when the spray nozzle is mounted on the discharge end of the spray gun in a predetermined orientation the locating pin extends into the alignment slot. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic longitudinal section view of a container coating station incorporating an illustrative spray nozzle for producing an asymmetrical fluid discharge distribution pattern embodying the present invention. 
       FIG. 2  is an enlarged perspective view of the illustrative asymmetric distribution spray nozzle of  FIG. 1  showing the alignment notch. 
       FIG. 3  is an exploded perspective view of the illustrative asymmetric distribution spray nozzle and an end of an illustrative spray gun having a complementary locating pin. 
       FIG. 4  is a perspective view of the illustrative asymmetric distribution spray nozzle arranged on the end of the spray gun of  FIG. 3 . 
       FIG. 5  is a perspective view of the illustrative asymmetric distribution spray nozzle secured on the end of the spray gun by a retaining nut. 
       FIG. 6  is a front view of the illustrative asymmetric distribution spray nozzle secured on the end of the spray gun by the retaining nut. 
       FIG. 7  is a schematic drawing showing an exemplary asymmetric fluid discharge pattern for the illustrative spray nozzle for a container coating operation. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now more particularly to  FIG. 1 , there is schematically shown, a portion of an exemplary container coating station that includes a spray nozzle  10  embodying the present invention which discharges, in this case, a coating material fluid in an asymmetrically distributed pattern. With the illustrated container coating station, open-ended containers  12  are indexed one-by-one to the coating station where the stationary spray nozzle  10  applies a coating material onto the interior surfaces of the container  12  through the open end  14 . The spray nozzle is attached to a spray gun  15  (not shown in  FIG. 1 ) that, in turn, is connected to a supply of the coating material. The coating material may comprise vinyl, epoxy, acrylic or other suitable materials. As the coating material is being applied, the container  12  is rotated about its longitudinal axis  16  relative to the spray nozzle  10  at a relatively high speed (e.g., 500–3000 rpm) so that the coating material is applied to the entire interior of the container. As will be understood by those skilled in the art, while the spray nozzle of the present invention is described in connection with a container coating application, it may be employed in other applications and systems where an asymmetrical fluid discharge pattern is desired. 
   To facilitate application of the coating material, the spray nozzle  10  is disposed on the longitudinal axis  16  of the container  12  a short distance from the open end  14  of the container as shown in  FIG. 1 . Additionally, the spray nozzle  10  is canted such that the centerline  18  of the nozzle is disposed at an angle θ relative to the longitudinal axis  16  of the container, which, in this case, is oriented substantially horizontal. To compensate for the greater distance the coating material must travel to reach the closed end of the container  12 , the spray nozzle  10  is arranged so that the portion of the spray pattern with the heaviest discharge is directed generally towards the intersection of the bottom wall and cylindrical sidewall of the container. As will be appreciated by those skilled in the art, the angle θ of the spray nozzle  10  relative to the longitudinal axis  16  of the container can vary depending on the configuration of the container  12  being coated. In most instances, however, the spray nozzle  10  is preferably arranged at an angle θ of approximately 5° to 20° relative to the longitudinal axis  16  of the container. 
   In the illustrated embodiment, the spray nozzle  10  includes a nozzle body  20  and a spray tip  22  having a dome shaped end wall  24  with a discharge orifice  26  formed therein, as best shown in  FIGS. 2 and 6 . The discharge orifice  26  has an irregular shape that is configured to produce a spray pattern having the desired asymmetrical distribution of the fluid discharge. In this case, the discharge orifice  26  of the spray nozzle  10  is configured so as to produce a flat fan shaped pattern in which the heaviest discharge is shifted from the center towards one end of the fan pattern. One preferred distribution pattern for the spray nozzle  10  is schematically shown in  FIG. 7 . In  FIG. 7 , the amount of flow at different points in the spray pattern or fan is illustrated by the shaded areas in the troughs a–l. With this distribution pattern, the maximum amount of fluid is discharged at a point (trough i in the illustrated embodiment) approximately midway from the center and one end of the fan. From the point of maximum discharge, the amount of fluid discharged tapers in a non-linear manner to minimum discharge points at either end of the spray fan (trough a and trough l in  FIG. 7 ). Additional details regarding how the discharge orifice can be configured to produce an improved fluid discharge pattern for container coating applications are provided in commonly owned U.S. Pat. No. 6,592,058 and U.S. patent application Ser. No. 09/967,417 the disclosures of which are incorporated herein by reference. 
   As will be appreciated by those skilled in the art, the present invention is not limited to spray nozzles that produce any particular fluid discharge pattern. For example, instead of the non-linear taper shown in  FIG. 7 , the discharge orifice  26  of the spray nozzle  10  could be configured to produce a discharge pattern in which the amount of discharge tapers linearly from the location of maximum discharge to either end of the spray pattern. The spray nozzle  10  could also be configured to produce a spray pattern in which the location of maximum discharge is located at or near one end of the spray pattern with the amount of discharge tapering to the other end of the discharge pattern. 
   In the illustrated embodiment, the spray nozzle  10  can be attached to the spray gun  15  using a retaining member  28 , in this case a retaining nut. More specifically, as shown in  FIG. 3 , the spray gun  15  includes a discharge end or tip  30  having a mounting surface  32  for receiving the spray nozzle  10 . As shown in  FIG. 3 , the stem  34  of the end of the spray gun  15  is threaded so that when the spray nozzle  10  is arranged in position on the discharge end  30  of the spray gun  15 , the spray nozzle  10  can be secured in place via the retaining nut  28  (see  FIGS. 4 and 5 ). In this case, the retaining nut  28  captures a flange  36  at the inlet end of the spray nozzle  10  so as to hold the spray nozzle on the spray gun  15 . 
   In order to help ensure that the spray nozzle  10  is oriented properly with respect to the objects being sprayed, in this case the containers, the spray nozzle  10  has an alignment notch  38  arranged in a predetermined position relative to the discharge orifice  26 . The alignment notch  38  provides a visual indicator that an installer can use to ensure that the spray nozzle  10  is installed in the proper orientation on the spray guns. In particular, the alignment notch  38  can be positioned such that when the spray nozzle  10  is installed properly on a spray gun, the alignment notch faces a given direction. Moreover, the predetermined position of the alignment notch  38  relative to the discharge orifice  26  can be the same for a group of spray nozzles such that when installed properly the alignment notches of the group of nozzles all face the same direction. As will be appreciated, this makes it easy for an installer to install the spray nozzles very quickly and accurately. 
   In the illustrated embodiment, the alignment notch  38  extends in a longitudinal direction along the outer surface of the side of the nozzle body  20  (see, e.g.,  FIGS. 2 and 4 ). The illustrated alignment notch  38  extends along a substantial portion of the length of the nozzle body  20 , in this case a majority (i.e., over one half) of the length, and cuts relatively deeply into the surface of the nozzle body. Thus, unlike an arrow, the alignment notch  38  provides a prominent structural feature that will not become obscured by a build-up of coating material on the spray nozzle  10 . 
   To prevent the spray nozzle  10  from being installed out of alignment, the spray gun  15  can be equipped with a locating pin  40  that is received in the alignment notch  38  when the spray nozzle  10  is properly installed on the spray gun  15 . In the illustrated embodiment, the locating pin  40  extends outward from the mounting surface  32  on the discharge end  30  of the spray gun (see, e.g.,  FIGS. 3 and 4 ). Moreover, so as to be able to receive the locating pin  40 , the alignment notch  38  extends through the retaining flange  36  at the inlet end of the spray nozzle  10 . The locating pin  40  is arranged on the spray nozzle  10  in a predetermined position, for example relative to the objects being sprayed, such that when the nozzle is positioned on the discharge end  30  of the spray gun  15  in the proper orientation, the locating pin  40  extends into the alignment notch  38  as shown in  FIGS. 4 and 6 . If the spray nozzle  10  is not oriented properly, the alignment notch  38  and the locating pin  40  will be misaligned and the installer will not be able to attach the spray nozzle  10  to the spray gun  15 . Thus, the locating pin  40  ensures that the spray nozzle  10  can only be installed in the proper orientation. 
   From the foregoing, it can be seen that the asymmetric discharge spray nozzle of the present invention allows an installer to determine quickly and easily whether the nozzle is installed in the proper orientation relative to the objects being sprayed. This helps reduce or eliminate errors in the installation of such spray nozzles that can be costly and time consuming to correct. Moreover, if the asymmetric spray nozzle of the present invention is utilized with a spray gun having a locating pin according to another aspect of the present invention, the possibility of the spray nozzle being installed in the wrong orientation can be even further reduced if not eliminated. 
   All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
   The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
   Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context