Patent Publication Number: US-7721531-B2

Title: Atomizing-nozzle orifice insert and method for manufacture thereof

Description:
TECHNICAL FIELD OF THE INVENTION 
   The present invention relates generally to mist heads, which atomize pressurized fluid. Specifically, the present invention relates to atomizing nozzles that are configured to consistently produce a uniform fine mist. 
   BACKGROUND OF THE INVENTION 
   Atomizing nozzles, also called mist heads, are used in connection with misting systems to produce a fog or fine mist. A fluid, typically water, is forced under pressure through the atomizing nozzles to produce the mist. Desirably, the mist is sufficiently fine so that it rapidly evaporates. As the mist evaporates, the general area around the atomizing nozzles becomes cooler. Rapid evaporation prevents people and property located in the mist from getting wet and enhances the cooling effect. Accordingly, misting systems are often used for cooling and for increasing humidity. 
     FIG. 1  shows a cross-sectional front view of a prior-art atomizing nozzle  20 . Prior-art atomizing nozzle  20  is made up of a nozzle body  22  conventionally formed of metal or plastic. Nozzle body  22  conventionally includes a metallic orifice insert  24 . Orifice insert  24  has a small orifice  26  through which the fluid passes under pressure to produce the desired fog or mist. In addition, an impeller  28 , also called a plunger or poppet, is positioned within a fluid chamber  30  that connects to orifice  26 . The action of impeller  28  within fluid chamber  30  fractures the fluid and produces a finer fog or mist. 
   Orifice  26  is typically formed of a hard metal, such as stainless steel, to minimize the effects of erosion. Those skilled in the art will appreciate that, in some embodiments, orifice  26  may be produced directly in nozzle body  22 , i.e., nozzle body  22  and orifice insert  24  may be formed as one piece. It will be appreciated, however, that having orifice  26  directly in nozzle body  22  increases the cost and difficulty of machining nozzle body  22 . 
   Conventionally, orifice  26  resides in orifice insert  24 . Since orifice insert  24  is small, typically less than 0.2 inch in diameter, machining is expensive and time-consuming. 
   Orifice insert  24  is typically pressed into place in nozzle body  22  with great force to produce a fluid-tight seal even when the fluid is under high pressure. This requires that orifice insert  24  be of sufficient strength to resist deformation during the pressing process. This, too, increases cost. 
   Since orifice insert  24  is pressed into the nozzle body with great force, it cannot thereafter be removed for subsequent cleaning of orifice  26  to remove any deposited mineral materials. In time, these deposited mineral materials will eventually completely block orifice  26  and inhibit passage of the fluid. Atomizing nozzle  20  will then no longer be able to produce the desired fog or mist. 
   Accordingly, conventional atomizing nozzles  20  are expensive to manufacture and become clogged during use. Such clogged atomizing nozzles  20  cannot readily be unclogged, necessitating the purchase and installation of replacement atomizing nozzles  20 . 
   Prior-art atomizing nozzle  20  conventionally has cup-shaped orifice insert  24 . That is, orifice insert  24  has a cylindrical shape with an inside wall  32  substantially parallel to a centerline  34 . The cup shape provides strength so as to avoid warpage of orifice insert  24  while being pressed into nozzle body  22 . 
   The cup shape of orifice insert  24 , while providing strength, adds significantly to fabrication costs. The small size of orifice insert  24  greatly increases the difficulty and care with which orifice insert  24  must be machined and handled. 
   Additionally, since conventional orifice inserts  24  are cup-shaped for increased strength, nozzle bodies  22  have a considerable length  36  to contain the cup. Such a “deep” body contains a considerable amount of material that serves no function but to accommodate a cup-shaped orifice insert  24 . This excess material undesirably increases the mass of nozzle body  22 . This increased mass equates to excesses in both the costs of raw materials to produce nozzle bodies  22  and the costs of shipping the finished atomizing nozzles  20 . 
   A need exists, therefore to configure and manufacture an atomizing nozzle at less expense than has been achieved conventionally. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an advantage of the present invention that an improved atomizing nozzle and method for manufacture thereof are provided. 
   Another advantage of the present invention is that an atomizing nozzle is provided that has a nozzle body constructed of a first metal and an orifice insert fabricated of a second metal. 
   Another advantage of the present invention is that an atomizing nozzle is provided that has an orifice insert formed from a metallic sheet material. 
   The above and other advantages of the present invention are carried out in one form by an atomizing nozzle for use in a misting system. The atomizing nozzle is made up of a nozzle body having a nozzle inlet end, having a nozzle outlet end, and encompassing a fluid chamber between the inlet and outlet ends, an orifice insert stamped from a metallic sheet material and affixed to the nozzle body proximate the outlet end, and an impeller configured to reside within the fluid chamber between the orifice insert and the inlet end. 
   The above and other advantages of the present invention are carried out in another form by a method of manufacturing an atomizing nozzle for use in a misting system. The method includes constructing a nozzle body encompassing a chamber, fabricating an orifice insert of a sheet material, producing an impeller, inserting the impeller into the chamber, and affixing the orifice insert into the nozzle body. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the Figures, wherein like reference numbers refer to similar items throughout the Figures, and: 
       FIG. 1  shows a cross-sectional front view of a prior-art atomizing nozzle. 
       FIG. 2  shows a front view of an atomizing nozzle in accordance with a preferred embodiment of the present invention; 
       FIG. 3  shows a top view of the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 4  shows a cross-sectional front view of an atomizing nozzle in accordance with a preferred embodiment of the present invention; 
       FIG. 5  shows a flowchart of a process to manufacture the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 6  shows a cross-sectional exploded front view taken at line  4 - 4  of  FIG. 3  demonstrating the components of the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 7  shows a flowchart of a subprocess to construct a nozzle body for the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 8  shows a flowchart of a subprocess to fabricate an orifice insert for the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 9  shows a top view of an orifice insert for the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 10  shows a cross-sectional front view taken at line  10 - 10  of  FIG. 9  of a sheet material during a first portion of the subprocess of  FIG. 8  in accordance with a preferred embodiment of the present invention; 
       FIG. 11  shows a cross-sectional front view taken at line  10 - 10  of  FIG. 9  of a sheet material during a second portion of the subprocess of  FIG. 8  in accordance with a preferred embodiment of the present invention; 
       FIG. 12  shows a cross-sectional front view taken at line  10 - 10  of  FIG. 9  of a sheet material during a third portion of the subprocess of  FIG. 8  in accordance with a preferred embodiment of the present invention; 
       FIG. 13  shows a cross-sectional front view of the orifice insert of  FIG. 9  taken at line  10 - 10  of  FIG. 9  in accordance with a preferred embodiment of the present invention; 
       FIG. 14  shows a flowchart of a subprocess to produce an impeller for the atomizing nozzle of  FIG. 2  in accordance with a preferred embodiment of the present invention; 
       FIG. 15  shows a top view of an impeller in accordance with a preferred embodiment of the present invention; 
       FIG. 16  shows a front view of an impeller in accordance with a preferred embodiment of the present invention; 
       FIG. 17  shows a cross-sectional front view taken at line  17 - 17  of  FIG. 4  of the atomizing nozzle of  FIG. 2  during insertion of the orifice insert into the nozzle body in accordance with a preferred embodiment of the present invention; 
       FIG. 18  shows a cross-sectional front view taken at line  17 - 17  of  FIG. 4  of the atomizing nozzle of  FIG. 2  after insertion of the orifice insert into the nozzle body in accordance with a preferred embodiment of the present invention; and 
       FIG. 19  shows a cross-sectional front view taken at line  4 - 4  of  FIG. 3  of the atomizing nozzle of  FIG. 2  during operation in accordance with a preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2  shows a front view and  FIG. 3  shows a top view of an atomizing nozzle  100  in accordance with a preferred embodiment of the present invention.  FIG. 4  shows a cross-sectional front view, taken at line  4 - 4  of  FIG. 3 , depicting atomizing nozzle  100  with an O-ring  102  removed for clarity. The following discussion refers to  FIGS. 2 ,  3 , and  4 . 
   Atomizing nozzle  100  is configured for attachment to a pipe (not shown) in a misting system (not shown), thereby providing a fine mist or fog for cooling and/or hydration. Atomizing nozzle  100  is made up of a nozzle body  104 , an orifice insert  106 , an impeller  108  (also known as a plunger or poppet), and O-ring  102 . Nozzle body  104  has an inlet end  110  and an outlet end  112 . Nozzle body  104  also encompasses a fluid chamber  114  between inlet end  110  and outlet end  112 . Orifice insert  106  is affixed to nozzle body  104  proximate outlet end  112 . Impeller  108  resides within fluid chamber  114  of nozzle body  104 . 
     FIG. 5  shows a flowchart of a process  300  to manufacture atomizing nozzle  100  in accordance with a preferred embodiment of the present invention.  FIG. 6  shows a cross-sectional exploded front view, taken at line  4 - 4  of  FIG. 3 , demonstrating the assembly of atomizing nozzle  100  in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIGS. 2 ,  3 ,  4 ,  5 , and  6 . 
   Atomizing nozzle  100  may be manufactured and assembled as delineated in process  300 . The components of atomizing nozzle  100  are created and integrated by subprocesses within process  300 . These subprocesses are discusses hereinafter and delineated in  FIGS. 7 ,  8 , and  14 . 
   As shown in  FIG. 5 , nozzle body  104  is constructed during a subprocess  310  of process  300 .  FIG. 7  shows a flowchart of subprocess  310  in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIGS. 2 ,  3 ,  4 ,  5 ,  6 , and  7 . 
   Nozzle body  104  is constructed by subprocess  310  of process  300 . Subprocess  310  contains tasks  311 ,  312 ,  313 ,  314 ,  315 , and  316  to form various features of nozzle body  104 . 
   In task  311 , subprocess  310  forms an insert recess  116  in nozzle body  104  proximate inlet end  110 . In the preferred embodiment, insert recess  116  is formed as substantially a right-cylindrical opening extending into nozzle body  104  from outlet end  110 . Insert recess  116  has a recess diameter  118  and a recess depth  120 . Insert recess  116  is configured to contain orifice insert  106 . 
   In task  312 , subprocess  310  forms a body chamber  122 . Body chamber  122  is formed as substantially a right-cylindrical opening extending into nozzle body  104  from insert recess  116 . Body chamber  122  has a body-chamber diameter  124  and a body-chamber length  126 . It will be appreciated that other shapes may be used for body chamber  122 . The use of another shape does not depart from the spirit of the present invention. 
   In task  313 , subprocess  310  forms a fluid inlet channel  128 . Inlet channel  128  is formed substantially as a right-cylindrical opening extending through nozzle body  104  from body chamber  122  to inlet end  110 . Inlet channel  128  has an inlet-channel diameter  130  and an inlet-channel length  132 . It will be appreciated that other shapes may be used for fluid inlet channel  128 . The use of another shape does not depart from the spirit of the present invention. 
   In task  314 , subprocess  310  forms a knurl  134  ( FIGS. 2 and 3 ) around an outside of nozzle body  104 . Knurl  134  serves to allow atomization nozzle  100  to be attached to and detached from a pipe (not shown) by hand. It will be appreciated that other methods of attachment and detachment may be possible or desirable. In this case, task  314  may form any desired shape or texture (e.g., a hexagonal shape). 
   In task  315 , subprocess  310  forms a seat  136  for O-ring  102 . O-ring seat  136  is depicted in  FIG. 4 , from which Figure O-ring  102  has been removed for clarity. O-ring  102  is depicted in  FIG. 2 , and is depicted seated in O-ring seat  136  in  FIG. 19  (discussed hereinafter). 
   And in task  316 , subprocess  310  forms threads  138 . Threads  138  serve to attach atomizing nozzle  100  to a pipe (not shown) of a misting system (not shown). It will be appreciated that other methods of attachment may be possible or desirable. In this case, task  314  may form the desired attachment means (e.g., a crimp fitting) without departing from the spirit of the present invention. 
   In the preferred embodiment, the misting system (not shown) is a high-pressure water-based misting system. Nozzle body  104  is therefore desirably constructed of a stable metal, such as brass, suitable for use with such a misting system. Those skilled in the art will appreciate that, depending upon the use for which the misting system is intended, other materials may be desirable. 
   Depending upon the material of which nozzle body  104  is to be constructed, subprocess  310  may involve molding, machining, or otherwise producing the features formed by tasks  311 ,  312 ,  313 ,  314 ,  315 , and  316  using established techniques. It will also be appreciated that the order of tasks  311 ,  312 ,  313 ,  314 ,  315 , and  316  within subprocess  310  is irrelevant to this discussion. For example, tasks  311 ,  312 ,  313 ,  314 ,  315 , and  316  may be performed substantially simultaneously if subprocess  310  constructs nozzle body  104  by molding. 
   As shown in  FIG. 5 , orifice insert  106  is fabricated during a subprocess  320  of process  300 .  FIG. 8  shows a flowchart of subprocess  320  in accordance with a preferred embodiment of the present invention.  FIG. 9  shows a top view of orifice insert  106  for atomizing nozzle  100 ,  FIGS. 10 ,  11 , and  12  show cross-sectional front views, taken at line  10 - 10  of  FIG. 9 , of a sheet material  140  during first, second, and third portions of the fabrication of orifice insert  106 , and  FIG. 13  shows a cross-sectional front view, taken at line  10 - 10  of  FIG. 9 , of orifice insert  106  in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIGS. 5 ,  6 ,  8 ,  9 ,  10 ,  11 ,  12 , and  13 . 
   Orifice insert  106  is fabricated by subprocess  320  of process  300  from sheet material  140  having a first surface  142 , a second surface  144 , and a material thickness  146 . In the preferred embodiment, sheet material  140  is desirably stainless steel and material thickness  146  is no greater than 0.055 inch. Ideally, material thickness  146  is 0.020 inch±0.0025 inch. 
   Subprocess  320  contains tasks  321 ,  322 ,  323 , and  324  to form various features of orifice insert  106 . In task  321  ( FIGS. 8 ,  9 , and  10 ), subprocess  320  begins the formation of an insert chamber  148  by forming a first substantially conical bevel  150  into first surface  142  of sheet material  140  about an arbitrary insert centerline  152  substantially perpendicular to first and second surfaces  142  and  144 . First bevel  150  is desirably formed by chamfering. 
   First bevel  150  is formed at a first-bevel angle  154 . First bevel  150  intersects first surface  142  in a substantially circular demarcation  156  having a first-bevel diameter  158 . 
   In task  322  ( FIGS. 8 ,  9 , and  11 ), subprocess  320  completes the formation of insert chamber  148  by forming a second substantially conical bevel  160  from first bevel  150  towards second surface  144  of sheet material  140  about centerline  152  and to a depth where remaining material of sheet material  140  at centerline  152  has a remaining thickness  162 . In the preferred embodiment, remaining thickness  162  is 0.001±0.001 inch, desirably ±0.00025 inch. Second bevel  160  is desirably formed by chamfering. 
   Second bevel  160  is formed at a second-bevel angle  164  less than first-bevel angle  154 . Second bevel  160  intersects first bevel  150  in a substantially circular demarcation  166  having a second-bevel diameter  168   
   In task  323 , subprocess  320  forms a fluid outlet channel  170  from second bevel  160  through to second surface  144  of sheet material  140  about centerline  152 . Desirably, outlet channel  170  is formed by boring. An outside end of outlet channel  170  (i.e., the end coincident with second surface  144 ) forms an orifice  176 . 
   Outlet channel  170  has an outlet-channel diameter  172  and an outlet-channel length  174 . Since orifice  176  is the outlet end of outlet channel  170 , outlet-channel diameter  172  is also the diameter of orifice  176 . In the preferred embodiment of the Figures, outlet-channel diameter  172  is 0.0157 inch±0.005 inch, desirably ±0.0002 inch. This is not a requirement of the present invention, however, and those skilled in the art will appreciate that outlet-channel diameter  172  may assume other values as required by specific applications. For example, nominal outlet-channel channel diameters  172  of 0.006, 0.008, 0.012, 0.015, 0.020, 0.025, and 0.030 inch have all been used for specific applications. The use of another value for outlet-channel diameter  172  does not depart from the spirit of the present invention. 
   In task  324 , subprocess  320  forms orifice insert  106  by stamping or punching a substantially cylindrical orifice insert  178  from sheet material  140  about centerline  152 . Orifice insert  178  has an insert diameter  180  substantially equal to recess diameter  118 . In the preferred embodiment, insert diameter  180  is 0.153 inch +0.100 −0.050 inch, desirably ±0.005 inch. Orifice insert  178  has an insert length  182  substantially equal to material thickness  146  and less than recess depth  120 . 
   In the preferred embodiment, orifice insert  106  is a metallic orifice insert. That is, orifice insert  106  is fabricated of metal. Desirably, orifice insert  106  is fabricated of a metal or an alloy of metals that is substantially non-reactive to air or water (or other fluid to be atomized by atomizing nozzle  100 ). By being substantially non-reactive, corrosion is kept to a minimum, and the useful lifetime of atomizing nozzle  100  is maximized. Desirably, orifice insert  106  is fabricated of a metal having a hardness at least as great as the hardness of the metal of which nozzle body  104  is constructed. In the preferred embodiment, nozzle body  104  is constructed of brass and orifice insert  106  is fabricated of stainless steel. Those skilled in the art will appreciate that orifice insert  106  may be fabricated of other materials, e.g., alloys of aluminum, titanium, and magnesium, without departing from the spirit of the present invention. 
   Those skilled in the art will appreciate that subprocess  320  may involve machining or otherwise producing the features formed by tasks  321 ,  322 , and  323  using established techniques. Subprocess  320  involves stamping for task  324 . It will also be appreciated that the order of tasks  321 ,  322 ,  323  within subprocess  320  is irrelevant to this discussion. It will be appreciated that task  324  of the preferred embodiment of subprocess  320  involves stamping to produce orifice insert  106 , and is therefore normally the last task of subprocess  320 , though this is not a requirement of the present invention. Stamping is desirable for task  324  because it allows the extraction of orifice insert  106  from sheet material  140  at a minimum cost and effort. This effects significant savings in the per-nozzle costs of atomizing nozzles  100 . 
   Referring to  FIGS. 9 and 13 , it may be seen that orifice insert  106  has the shape of a disk with a depressed center. That is, first and second bevels  150  and  160  produce “interior walls” positioned obliquely relative to centerline  152 . This is in marked contrast to the cup-shaped prior art orifice insert  24  of  FIG. 1 , where inside walls  32  are substantially parallel to centerline  34 . The absence of the cup shape allows orifice insert  106  to be significantly thinner than prior-art orifice insert  24 . This in turn allows a length  232  of nozzle body  104  ( FIG. 4 ) to be significantly shorter than the length  36  of prior-art nozzle body  22 , with corresponding savings in material and mass. 
   Within orifice insert  106 , second-bevel demarcation  166  divides insert chamber  148  into a first-bevel portion  184  and a second-bevel portion  186 . First-bevel portion  184 , i.e., that portion of insert chamber  148  bounded by first bevel  150  between first-bevel demarcation  156  and second-bevel demarcation  166 , is contiguously joined with body chamber  122  ( FIG. 6 ) to form fluid chamber  114 . This is discussed in more detail hereinafter. 
   Second-bevel portion  186  is that portion of insert chamber between second-bevel demarcation  166  and outlet channel  170 . Second-bevel portion  186  serves as a chamber between impeller  108  and orifice  176  in which the water or other fluid may gather prior to final atomization. This chamber serves to produce a finer mist. 
   Second-bevel angle  164  is less than first-bevel angle  154  to increase the size of second bevel portion  186  to further improve atomization. Those skilled in the art will appreciate that, in some embodiments, second-bevel angle  164  may substantially equal first-bevel angle  154 . That is, second bevel  160  may be omitted, and the chamber between impeller  108  and orifice  176  may be produced by an extension of first bevel  150  to outlet channel  170 . Such an embodiment may be produced by omitting task  322  of subprocess  320  ( FIG. 8 ). The omission of task  322  does not depart from the spirit of the present invention. 
   As shown in  FIG. 5 , impeller  108  is produced during a subprocess  330  of process  300 .  FIG. 14  shows a flowchart of subprocess  330  in accordance with a preferred embodiment of the present invention.  FIG. 15  shows a top view of impeller  108  depicting an impeller outlet end  188 , and  FIG. 16  shows a front view of impeller  108  in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIGS. 4 ,  5 ,  6 ,  14 ,  15 , and  16 . 
   Subprocess  330  includes tasks  331 ,  332 ,  333 ,  334 , and  335 . Impeller  108  is a cylindroid having a length  189  and a diameter  190 . Impeller  108  has outlet end  188 , an inlet end  192 , and a cylindrical body  194  between outlet and inlet ends  188  and  192 . 
   In task  331 , subprocess  330  forms body  194  of impeller  108 . Impeller body  194  has a diameter  196  substantially equal to impeller diameter  190 . Impeller body  194  also has a length  198  that is less than impeller length  189 . 
   In task  332 , subprocess  330  forms a knurl  200  around an outside surface  202  of impeller body  194 . Impeller knurl  200  serves to fracture the water or other fluid during operation. Those skilled in the art will appreciate that knurl  200  is not a requirement of the present invention. The omission of task  332 , and of knurl  200 , does not depart from the spirit of the present invention. 
   In task  333 , subprocess  330  forms a raised substantially circular planar surface  204  at impeller outlet end  188 . Planar surface  204  has a diameter  206  less than that of impeller diameter  190 . 
   In task  334 , subprocess  330  forms grooves  208  at impeller outlet end  188 . Grooves  208  have an outer edge  210 , which is substantially tangential to a circumference  212  of planar surface  204 . Grooves  208  serve to further fracture the water or other fluid during operation. 
   And in task  335 , subprocess  330  forms a chamfer  214  at impeller inlet end  192 . Chamfer  214  aids in the insertion of impeller  108  into nozzle body  104 . Those skilled in the art will appreciate that chamfer  214  is not a requirement of the present invention. The omission of task  335 , and of chamfer  214 , does not depart from the spirit of the present invention. 
   In the preferred embodiment of the Figures, impeller  108  is depicted as a waisted impeller. In practice, impeller  108  may be cylindrical, waisted, frusto-conical, or any other form known to those skilled in the art. The form of impeller  108  is irrelevant to the present invention and other forms may be used without departing from the spirit of the present invention. 
   Those skilled in the art will appreciate that, depending upon the material of which impeller  108  is produced, subprocess  330  may involve molding, machining, or otherwise producing the features formed by tasks  331 ,  332 ,  333 ,  334 , and  335  using established techniques. It will also be appreciated that the order of tasks  331 ,  332 ,  333 ,  334 , and  335  within subprocess  330  is irrelevant to this discussion. For example, tasks  331 ,  332 ,  333 ,  334 , and  335  may be performed substantially simultaneously if subprocess  330  produces impeller  108  by molding. 
   Those skilled in the art will appreciate that the order in which subprocesses  310 ,  320 , and  330  are performed, i.e., the order in which nozzle body  104 , orifice insert  106 , and impeller  108  are produced, is irrelevant. Changing the order from that exemplified in this discussion does not depart from the spirit of the present invention. 
   The following discussion refers to  FIG. 4 . 
   Fluid chamber  114  is formed of insert chamber  148  and body chamber  122 . Impeller  108  is configured to reside within fluid chamber  114 . In order to fulfill its function, impeller  108  should be able to spin, vibrate, and otherwise move within fluid chamber  114 . Therefore, fluid chamber  114  should have a diameter greater than impeller diameter  190  and a length greater than impeller length  189 . 
   Fluid chamber  114  is formed by concatenating body chamber  122  and first-bevel portion  184  of insert chamber  148 . First-bevel portion  184  of insert chamber  148  has a first-bevel-portion length  216 . Body chamber  122  has body chamber length  126 . Therefore, fluid chamber  114  has a length  218  that is the sum of first-bevel-portion length  216  and body chamber length  126 . 
   Impeller  108  should be free to move inside fluid chamber  114 . Therefore, impeller diameter  190  is less than body-chamber diameter  124 . Similarly, impeller length  189  is less than fluid-chamber length  218 . 
   Fluid chamber  114  is bound on one end by inlet channel  128  and on the other end by second-bevel portion  186  of insert chamber  148 . Since it is desirable that impeller  108  be retained within fluid chamber  114 , impeller diameter  190  is greater than either diameter  130  of inlet channel  128  or diameter  168  of second-bevel demarcation  166 . 
     FIG. 6  also shows a cross-sectional front view of atomizing nozzle  100  prior to assembly and  FIGS. 17 and 18  show a magnified portion of atomizing nozzle  100  encompassed by line  17 - 17  of  FIG. 4  during ( FIG. 17 ) and after ( FIG. 18 ) insertion of orifice insert  106  into nozzle body  104  in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIGS. 2 ,  3 ,  4 ,  5 ,  6 ,  17 , and  18 . 
   With the completion of subprocesses  310 ,  320  and  330 , the principal components of atomizing nozzle  100  are ready for assembly. In a task  340  of process  300  ( FIG. 4 ), inlet end  192  of impeller  108  is inserted into body chamber  122  through insert recess  116 . Chamfer  214  guides impeller  108  into body chamber  122 . Since impeller diameter  190  is greater than inlet-channel diameter  130 , impeller  108  is inhibited from entering inlet channel  128  and remains in body chamber  122 . 
   In a task  350  of process  300 , orifice insert  106  is affixed to nozzle body  104 . In the preferred embodiment, nozzle body  104  is constructed of brass and orifice insert  106  is fabricated of stainless steel. It will be appreciated, however, that these precise materials are not a requirement of the present invention and other materials may be used. 
   Orifice insert  106  is inserted into insert recess  116  or nozzle body  104 . Desirably, orifice insert  106  and insert recess  116  are dimensioned so that insert diameter  180  is substantially equal to recess diameter  118 . This allows orifice insert  106  to be press-fitted into insert recess  116  in a manner well known to those skilled in the art. Desirably, insert length  182  is less than recess depth  120 , thereby allowing orifice insert  106  to be pressed to the bottom of insert recess  116  leaving a mounting recess  220 . A crimping or riveting tool  222  ( FIG. 17 ) may then be used to distort an edge  224  of insert recess  116 . Distorted edge  226  ( FIG. 18 ) then entraps orifice insert  106  inside of insert recess  116 . 
   Those skilled in the art will appreciate that other methods of affixing orifice insert  106  to or into nozzle body  104  may be used without departing from the spirit of the present invention. 
   In a final task  360 , O-ring  102  is added to atomizing nozzle  100 . O-ring  102 , in conjunction with O-ring seat  136 , allows atomizing nozzle  100  to make a watertight connection with a pipe (not shown) of the misting system (not shown). 
   Those skilled in the art will appreciate that the method of assembling atomizing nozzle  100  described hereinbefore is exemplary only, and that a plurality of other equivalent methods may be used. The use of another method of assembly does not depart from the spirit of the present invention. 
     FIG. 19  shows a cross-sectional front view taken at line  4 - 4  of  FIG. 3  of atomizing nozzle  100  during operation in accordance with a preferred embodiment of the present invention. The following discussion refers to  FIG. 19 . 
   When atomizing nozzle  100  is connected to a pipe (not shown) of a misting system (not shown) and pressure is applied, water  228  (or other fluid) is forced into fluid inlet channel  128 . From fluid inlet channel  128 , water  228  enters fluid chamber  114 . In fluid chamber  114 , water  228  flows around impeller  108 , imparting spinning, vibrating, and other motions to impeller  108 . The motions of impeller  108  cause water  228  to fracture, i.e., produces cavitation of water  228 . Fractured water  228  flows from fluid chamber  114  into outlet channel  170 . Water  228  then exits outlet channel  170  via orifice  176  as a fine mist or fog  230 . 
   The following discussion refers to  FIGS. 1 ,  4 ,  1 ,  11 ,  12 , and  13 . 
   One distinct advantage of atomizing nozzle  100  over prior-art atomizing nozzle  20  is that orifice insert  106  was fabricated from sheet material  140  and has an insert length  182  no greater than 0.055 inch. This allows nozzle body  104  to have a length  232  considerably less than the length  36  of prior-art nozzle body  22 . Nozzle body  104  therefore realizes significant savings in material over prior-art nozzle body  22 . These savings in material produce a decrease in the mass of nozzle body  104  over prior-art nozzle body  22 . This decease in mass equates to reductions in both the costs of raw materials to produce nozzle bodies  104  and the costs of shipping the finished atomizing nozzles  100 . 
   In summary, the present invention teaches an improved atomizing nozzle  100  and a process  300  for the manufacture of atomizing nozzle  100 . Atomizing nozzle  100  has a nozzle body constructed of a first metal, an orifice insert  106  fabricated of a sheet material  140  of a second metal, and an impeller  108 . Atomizing nozzle  100  is manufactured of materials to resist the rapid build-up of residual mineral materials contained in the water  228  or other fluid. 
   Although the preferred embodiments of the invention have been illustrated and described in detail, it will be readily apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.