Abstract:
A carrier fluid and an added input fluid are mixed together in a static mixer to create an emulsified output fluid mixture. The static mixer comprises a plurality of mixing chambers whose cross-sectional size expand considerably relative to an inlet, a series of bent and curved baffle plates which divert, rotate, divide, reverse and otherwise create turbulence in the combined flow, and inlet chamber in which the added input fluid is dispensed upstream into the carrier fluid, and a number of other structural mixing elements which, through turbulence, abrupt pressure drops and velocity changes, subdivide the added input mixture into very small volumetric quantities evenly dispersed within the carrier fluid to create a homogeneous output fluid mixture.

Description:
[0001]    This invention relates to static mixing, and more particularly to a new and improved static mixer and method for continuously mixing, dispersing or emulsifying two or more different input fluid substances which are usually not soluble or chemically combinable with one another, to create a single highly-homogeneous output fluid mixture of the multiple fluid substances. 
       BACKGROUND OF THE INVENTION 
       [0002]    A static mixer is a device which does not require an external motor and mixing paddles or stirrers to mix or combine different substances. In most cases, the static mixer has no moving parts. Instead, the static mixer uses one or more stationary structural mixing elements which cause the fluid passing through the static mixer to experience abrupt variations in velocity and pressure. The variations in velocity and pressure create turbulence in the fluid. The turbulent fluid creates shear forces which disperse and distribute volumetric quantities of one of the input fluid substances, referred to herein as the added input fluid substance or added input fluid, within another one of the input fluid substances, referred to herein as the carrier fluid substance or the carrier fluid. The turbulence results principally from pressurized and energized interaction of the fluid with the structural mixing elements as the fluid is forced through the static mixer. 
         [0003]    With sufficient induced turbulence, the added input fluid is dispersed evenly within the carrier fluid. The effectiveness of the mixing is therefore directly related to the ability of the structural mixing elements to induce sufficient turbulence to disperse the added fluid within the carrier fluid. 
         [0004]    In addition to thoroughly dispersing the added input fluid within the carrier fluid, it is also desirable to subdivide and separate the added input fluid into very small volumetric quantities. The added input fluid may be powdered grains of solid material, a gas or a liquid. In the case of powdered grains of solid material as the added input fluid, the individual grains may adhere together in clumps, even when surrounded in the carrier fluid and subjected to turbulence. In the case of a gaseous added fluid, large bubbles of the added fluid may remain in the carrier fluid even when subjected to turbulence. In the case of a liquid added input fluid, the surface tension of that liquid may create large drops of the added input fluid, and those large drops may remain distributed in the carrier fluid even under the influence of turbulence. 
         [0005]    Even though the clumps of powdered grains, or the large bubbles, or the large drops, may be uniformly mixed with the carrier fluid, the output mixture may still lack the desired level of homogeneity, because the clumps, bubbles and drops have not been subdivided into smaller parts. Under such circumstances, the static mixer lacks the capability to completely subdivide the added input fluid, although the larger clumps, bubbles and drops may be uniformly distributed within the output fluid. 
         [0006]    An effective static mixer must therefore achieve not only an effective distribution of the added input fluid with the carrier fluid, but it must also effectively subdivide added input fluid into very small volumetric quantities, to achieve a highly homogeneous output fluid mixture. 
         [0007]    Subdividing the added input fluid into very small volumetric quantities is particularly important when the added input fluid must be distributed over a large surface after it has been mixed with the carrier fluid. For example, in the case where the added input fluid is a particular chemical which is used to coat an object for some beneficial purpose, if the added input chemical has not been subdivided into very small volumetric quantities, the coating of the object will not be uniform because the clumps, large drops or large bubbles will create a non-uniform distribution when they interact with the object. Under such circumstances, a greater amount of the added input chemical will usually be required to coat the object adequately, due to the non-uniformity of the volumetric quantities of the added input fluid in the carrier fluid. This situation usually results in a higher cost of application, because more of the added input chemical is required than would otherwise be the case with a more thorough distribution of uniformly and finely subdivided volumetric quantities of the added input fluid in the carrier fluid. The effectiveness of the static mixer therefore directly affects the cost of use. 
         [0008]    A typical use application of the static mixer is to pressurize the flow of carrier fluid with a pump before the carrier fluid is delivered to the static mixer, and thereafter use the pressurized output flow from the static mixer after the added input fluid has been mixed within the static mixer. Under such circumstances, there is usually a minimum pressure requirement in the output flow from the static mixer to accomplish the desired application. Because the static mixer consumes energy from the pressurized carrier fluid to obtain the energy for mixing the added fluid with the carrier fluid, pressure and energy is lost within the static mixer to achieve the mixing effect. It is desirable to minimize the amount of energy loss within the static mixer, without sacrificing the creation of sufficient turbulence to achieve thorough dispersal and subdivision of the added input fluid within the carrier fluid. Minimizing this energy loss reduces the cost of operation, by reducing the amount of energy consumed by the motors driving the pumps which supply the carrier fluid to the static mixer. 
         [0009]    Another consideration relates to the physical size of the static mixer. Many applications for static mixers do not permit relatively large physical size devices to be used because of space constraints. Large static mixers can generally achieve more thorough mixing by adding more structural mixing elements, thereby increasing the overall physical size of the static mixer, and increasing the amount of energy consumed in achieving the level of mixing. The increased size and the number of structural mixing elements adds to the cost of the mixer, and may require the larger pumps and motors to supply more energy to the carrier fluid in order to achieve thorough mixing. 
         [0010]    Inefficient static mixers which consume additional energy by creating high pressure drops cost more money to operate because the pumps which supply the carrier fluid must be larger and must use more energy to create sufficient pressure in the output fluid flow to achieve the purposes to which that output fluid flow is to be put. The pumps and related hardware must be constructed to withstand higher pressures and higher capacities, which add to the cost of the entire mixing system. 
         [0011]    The effectiveness or efficiency of the static mixer is dependent upon the effectiveness of the structural mixing elements which create the abrupt variations in velocity and pressure to induce the turbulence. A greater degree of turbulence generally translates into a more thorough dispersal of the added input fluid in the carrier fluid, as well as more effective subdivision of the volumetric quantities of the added input fluid dispersed within the carrier fluid. 
         [0012]    A variety of different configurations and types of structural mixing elements have been devised and employed in static mixers. Some types of structural mixing elements are better suited than other types of such elements for mixing different types and viscosities of added input fluids and carrier fluids. Some types of structural mixing elements are more effective in achieving different types and intensities of turbulence. Under such circumstances, a single type of static mixer may not achieve a universal and desired level of effectiveness in mixing a variety of different added input fluids and carrier fluids. 
         [0013]    Furthermore, some configurations and types of structural mixing elements are more effective in creating a high level of turbulence without consuming an excessive amount of energy from the pressurized flow of the carrier fluid. Stated differently, the degree to which the fluids are uniformly mixed by the static mixer may not directly correlate to the amount of pressure drop or energy consumed by the mixer. 
       SUMMARY OF THE INVENTION 
       [0014]    The static mixer of this invention uses structural mixing elements which achieve both a uniform dispersal of the added input fluid within the carrier fluid, as well as an effective subdivision of the added input fluid into very small volumetric quantities which are uniformly dispersed within the carrier fluid, to achieve a very homogeneous output fluid mixture. The mixing is effective on a variety of different added input and carrier fluids, making the static mixer applicable to a larger variety of mixing applications. The static mixer achieves effective mixing by consuming a reduced amount of energy from the input carrier fluid, thereby creating a relatively lower pressure drop compared to other known types of static mixers which achieve a similar degree of homogeneity in the output fluid mixture. The type, organization and arrangement of the structural mixing elements results in a relatively compact sized static mixer which can be used in a variety of applications and which can be conveniently retrofitted into existing applications. The higher efficiency in mixing and the more homogeneous output fluid reduces use costs, because less energy is consumed in achieving the mixing and less of the typically-expensive added input fluid is required. The size and efficiency of the static mixer also reduces its cost of use because less equipment, such as pumps, are needed in conjunction with the static mixer. These same advantages and improvements are also achieved in the context of the methodology of this invention. 
         [0015]    These benefits and improvements are achieved by a static mixing apparatus which mixes a carrier fluid and an added input fluid to create an output fluid mixture. An inlet portion of the static mixing apparatus comprises an inlet chamber which receives and combines together the carrier fluid and the added input fluid as a combined fluid. A main mixing portion of the static mixing apparatus is connected to the inlet portion to receive the combined fluid from the inlet chamber. The main mixing portion comprises a housing which defines an elongated cavity and a plurality of structural mixing elements positioned throughout the elongated cavity. The plurality of structural mixing elements disburse and subdivide volumetric quantities of the added input fluid within the carrier fluid due to interactive movement of the combined fluid with the structural mixing elements. An output portion of the static mixing apparatus is connected to the main mixing portion to receive the combined fluid from the terminal end of the elongated cavity after interacting with the structural mixing elements and to deliver the combined fluid as the output fluid mixture. 
         [0016]    The structural mixing elements within the elongated cavity of the main mixing portion comprise first and second mixing chambers, each of which has an inlet passageway through which the combined fluid is received. The cross-sectional size of the inlet passageway to each mixing chamber is substantially smaller than the cross-sectional size of the mixing chamber having that inlet passageway. The substantially larger cross-sectional size of each mixing chamber has the effect of abruptly decreasing pressure and flow rate of the combined fluid entering the mixing chamber through the inlet passageway to induce turbulence in the combined fluid within the mixing chamber. 
         [0017]    The structural mixing elements also comprise a plurality of baffle plates sequentially positioned within the elongated cavity. Each baffle plate includes a plurality of openings to pass the combined fluid through the baffle plates and a plurality of curved portions to deflect the combined fluid to induce turbulence. At least two of the baffle plates occupy relative rotationally offset relationships within the elongated cavity in which the openings and the curved portions cause the combined fluid to rotate within the elongated cavity when flowing downstream between the two baffle plates. 
         [0018]    Additional features of the structural mixing elements and the static mixing apparatus include some or all of the following characteristics. 
         [0019]    A flow reducer is positioned between the first and second mixing chambers to converge the combined fluid from the first mixing chamber into a tube having a substantially smaller cross-sectional size than the cross-sectional size of the first mixing chamber. The tube comprises the inlet passageway into the second mixing chamber, and the tube projects into the second mixing chamber to deliver the combined flow into the second mixing chamber at a position downstream of a location where the second mixing chamber commences, thereby inducing more turbulence in the combined fluid in the second mixing chamber. The second mixing chamber may be located upstream within the elongated cavity relative to the plurality of baffle plates. 
         [0020]    Each of the plurality of baffle plates includes curved portions. The curved portions may be bent wing portions, with adjacent wing portions bent in opposite directions relative to one another to define the openings through the baffle plates and to divert the flow of combined fluid passing through the openings. The baffle plates may occupy relative rotationally offset relationships within the elongated cavity to rotate and divide the combined flow within the elongated cavity. 
         [0021]    A support plate is positioned between and connected to a preceding upstream baffle plate and a subsequent downstream baffle plate. The support plate has at least one internal opening for conducting the combined fluid through the support plate. A seal extends between the support plate and the surface of the housing which defines the cavity to divert any combined fluid flowing along the surface of the housing through each internal opening of the support plate. 
         [0022]    A first support structure extends between the preceding upstream baffle plate and the support plate and the flow reducer to establish the positions of the first mixing chamber, the flow reducer, the second mixing chamber, the preceding upstream baffle plate and the support plate, within the elongated cavity. A second support structure extends between each baffle plate and support plate to connect and orient the baffle plates and support plate within the cavity. The first and second support structures, the flow reducer, the plurality of baffle plates and the support plate comprise a unitary main mixing assembly. The main mixing assembly is insertable into and removable from the cavity as a unit. A ring is connected adjacent to the terminal end of the cavity to retain the main mixing assembly within the cavity. 
         [0023]    The curved portions of the baffle plates may be formed as helical spirals. The helically spiraled baffle plates are connected together in a sequence in which each subsequent baffle plate is reversed in rotational direction compared to the rotational direction of the helical spiral of the preceding baffle plate. In addition, a leading edge of the subsequent helically spiraled baffle plate is oriented perpendicular to a trailing edge of the preceding helically spiraled baffle plate. 
         [0024]    The inlet passageway to the first mixing chamber is an orifice extending from the inlet chamber into the first mixing chamber. Extending into the orifice is at least one vane which angles relative to an axis through the orifice to rotate the flow of combined fluid when passing through the orifice. 
         [0025]    An injector within the inlet chamber injects the added input fluid in an upstream direction relative to the carrier fluid received in the inlet chamber. The inlet chamber has a cross-sectional size which is substantially larger than the cross-sectional size of an inlet conduit supplying the carrier fluid into the inlet chamber, to abruptly decrease the pressure and flow rate and thereby induce turbulence in the combined fluid within the inlet chamber. Alternatively the inlet portion comprises a body which defines a venturi through which the carrier fluid flows. The venturi creates a relative low pressure area within which the added fluid is delivered. 
         [0026]    The invention also involves a method of mixing a carrier fluid and an added input fluid to create an emulsified output fluid mixture. The method involves conducting the carrier fluid and the added input fluid through a static mixing apparatus of the type previously described to create the emulsified output fluid mixture. 
         [0027]    A more complete appreciation of the present invention and its scope may be obtained from the accompanying drawings, which are briefly summarized below, from the following detailed descriptions of presently preferred embodiments of the invention, and from the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a perspective view of a static mixer which embodies the present invention. 
           [0029]      FIG. 2  is a longitudinal cross-sectional view of the static mixer shown in  FIG. 1 . 
           [0030]      FIG. 3  is a perspective view of a main mixing assembly  30  of the static mixer shown in  FIGS. 1 and 2 , with a portion of a flow reducer broken out. 
           [0031]      FIG. 4  is a partial perspective and cross-sectional view of an input portion of the static mixer shown in  FIGS. 1 and 2 . 
           [0032]      FIG. 5  is a partial elevational view of an orifice between the input portion and a main mixing portion of the static mixer shown in  FIG. 2 , taken substantially in the plane of line  5 - 5  in  FIG. 2 . 
           [0033]      FIG. 6  is a perspective view of a winged baffle plate of the main mixing portion of the static mixer shown in  FIGS. 2 and 3 . 
           [0034]      FIG. 7  is a perspective and longitudinal cross-sectional view of an alternative to an input portion of the static mixer shown in  FIGS. 2 and 4 . 
           [0035]      FIG. 8  is a perspective and longitudinal cross-sectional view of another alternative to the input portions shown in  FIGS. 2 ,  4  and  7 . 
           [0036]      FIG. 9  is a perspective view of three series-connected half-flight spiral helix baffle plates which may be linked in a similar manner form an alternative to the series of winged baffle plates and support plates of the main mixing assembly shown in  FIGS. 2 and 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    A static mixer  10  which embodies the present invention is shown in  FIGS. 1 and 2 . The static mixer  10  mixes an input carrier fluid  12  with a relatively smaller amount of an added input fluid  14  to achieve an output fluid mixture  16  which is a substantially homogeneous dispersal of very finely subdivided volumetric quantities (powder grains, drops or bubbles) of the added input fluid  14  dispersed throughout the carrier fluid  12 . The static mixer  10  is a continuous flow type mixer in which the carrier fluid  12  and the added input fluid  14  are continuously supplied to static mixer  10  to create the output fluid mixture  16 . Typically, the carrier fluid  12  will have a much higher volumetric flow rate than the added input fluid  14 , although the static mixer  10  will also accommodate comparable volumetric flows of the carrier fluid  12  and the added input fluid  14 . The carrier fluid  12  and the added input fluid  14  are pressurized by pumps (not shown) before delivery into the static mixer  10 . In many cases, the output fluid mixture  16  is delivered with enough pressure for particular applications, such as spraying or coating. 
         [0038]    The static mixer  10  includes an input portion  17  in which the carrier fluid  12  and the added input fluid  14  are received and in which some mixing occurs. An inlet conduit  18  receives the carrier fluid  12  and supplies the carrier fluid  12  to an injector body  20 . The injector body  20  receives the added input fluid  14  supplied to the mixer  10 . The added input fluid  14  is initially dispersed within the carrier fluid  12  within the injector body  20  and the combined fluid is then conducted into the other portions of the static mixer  10 . 
         [0039]    The static mixer  10  also includes a main mixing portion  19  which receives the combined fluid from the input portion  17  and in which the majority of the mixing between the carrier fluid  12  in the added input fluid  14  is achieved. The main mixing portion  19  includes a cylindrical housing  22  which defines a cylindrical interior cavity  24  within which a main mixing assembly  30  ( FIGS. 2 and 3 ) creates and achieves the majority of the mixing within the mixer  10 . The main mixing assembly  30  includes and defines a plurality of structural mixing elements which interact with the flow of combined fluid to mix the carrier and added input fluids  12  and  14  as they pass through the cavity  24 . The main mixing effect is achieved by a combination of abrupt pressure and flow rate changes and flow deflection and division, all of which creates turbulence. 
         [0040]    The static mixer  10  also includes an output portion  31  which receives the combined fluid from the main mixing portion  19  and which delivers the output fluid mixture  16  from the static mixer after a slight amount of additional mixing occurs within the output portion  31 . An outlet conduit  32  of the output portion  31  conducts the mixed output fluid  16  from the static mixer  10 . 
         [0041]    The injector body  20  of the input portion  17  is connected between a flange  34  which extends radially outward from a downstream end of the inlet conduit  18  and a flange  36  which extends radially outward from an upstream end of the housing  22 . The flanges  34  and  36  are integrally and sealingly connected to the inlet conduit  18  and the housing  22 , respectively, such as by welding. The injector body  20  is held between the flanges  34  and  36  by nuts  38  screwed onto studs  40  which extend forward from the flange  36  of the housing  22 . Conventional spiral wound pipe flange gaskets (not shown) are positioned between both sides of the injector body  20  and the flanges  34  and  36  to seal the injector body  20  to the flanges  34  and  36  when the nuts  38  are tightened. 
         [0042]    The injector body  20  defines an internal inlet chamber  44  in which at least one injection nozzle  46  is located, as shown in  FIGS. 2 and 4 . The injection nozzle  46  is attached to an end of a pipe  48  which extends through the injector body  20  and into the inlet chamber  44 . The injection nozzle  46  may be formed by one or more very small diameter holes formed in a closed end of the pipe  48 , or by a conventional injection nozzle head (not shown) connected to an open end of the pipe  48 . The added input fluid  14  is supplied through the closed pipe  48 , and the injection nozzle  46  sprays the added input fluid  14  upstream into the carrier fluid  12  within the inlet chamber  44 . The upstream spray of the added input fluid  14  into the carrier fluid  12  assists in initially distributing the added input fluid into the carrier fluid, as compared to injecting the added input fluid downstream which would tend to cause a mostly non-distributed flow stream of added input fluid surrounded by the larger flow of carrier fluid. 
         [0043]    The added input fluid  14  is introduced into the inlet chamber  44  at a higher pressure than the pressure of the carrier fluid  12  within the inlet chamber  44 , to prevent the carrier fluid  12  from flowing into the injection nozzle  46 . More than one injection nozzle  46  could be used, to deliver more of the added input fluid into the carrier fluid  14  within the inlet chamber  44 , and/or to inject multiple added input fluids into the carrier fluid. 
         [0044]    The relative proportion of carrier fluid  12  and the added input fluid  14  in the output fluid  16  is achieved by varying the pressure at which the carrier fluid  12  is supplied to the inlet chamber  44  relative to the pressure at which the carrier fluid is delivered through the input conduit  18 . Of course, the size of the input conduit  18  and the size and number of injection nozzles  46  can also be adjusted to vary the relative proportion of carrier fluid  12  to added input fluid  14  in the output fluid mixture  16 . 
         [0045]    The inlet chamber  44  in the injector body  20  is larger in diameter and volumetric size than the inside diameter and volumetric size of the inlet conduit  18 . As a result, the transition from the smaller inlet conduit  18  to the larger inlet chamber  44  causes an abrupt pressure drop and decrease in flow rate of the carrier fluid  12  within the inlet chamber  44 , both of which induce turbulence in the combined fluid in the inlet chamber  44 . The turbulence of the carrier fluid  12  in the inlet chamber  44  further assists in dispersing the upstream-injected added input fluid  14  into the carrier fluid  12  within the inlet chamber  44 . 
         [0046]    A perforated plate  52  extends across a rear portion of the inlet chamber  44 , as shown in  FIGS. 2 and 4 . Holes  54  in the perforated plate  52  introduce a slight amount of flow disturbance or turbulence, caused by abrupt pressure and velocity changes as the fluid passes through the holes  54 . The resulting induced turbulence achieves some mixing within the inlet chamber  44  both in front of the holes  54  in the perforated plate  52  and after the fluid flows out of the holes  54  in the perforated plate  52 . 
         [0047]    The fluid from the inlet chamber  44  enters the main mixing portion  19  through an orifice  56  formed in the flange  36 , as shown in  FIGS. 2 and 5 . The orifice  56  has a diameter, or cross-section size which is less than the diameter or size of the inlet chamber  44  and the cumulative size of the holes  54  in the perforated plate. The reduced diameter of the orifice  56  causes an abrupt increase in pressure and flow rate of the combined fluid entering the orifice  56 . 
         [0048]    The orifice  56  has a plurality of radially extending and axially angled vanes  58  which extend inward into the flow through the orifice  56 , as shown in  FIGS. 2 and 5 . The angled orientation of the vanes  58  relative to an axis through the orifice  56  create mechanical rotation of the fluid passing through the orifice  56 . The mechanical rotation of the fluid passing through the orifice  56  creates flow disturbances which further aid mixing. Furthermore, the orifice  56  is preferably tapered to expand radially outward in the downstream direction, as shown in  FIG. 2 . A radial expansion causes the flow rate of the combined fluid to decrease slightly as it passes through the orifice  56 . The decreased flow rate and the mechanical rotation induced by the vanes  58  combine to create turbulence through the orifice  56  to further contribute to mixing. 
         [0049]    The fluid exiting the orifice  56  enters a relatively large mixing chamber  60  defined by the substantially larger diameter of the cavity  24  of the housing  22 . The transition from the orifice  56  to the mixing chamber  60  is abrupt and substantial, which creates an abrupt and substantial pressure drop and an abrupt and substantial reduction in the flow rate, both of which induce turbulence and shear within the fluid in the mixing chamber  60 . The turbulence substantially contributes to further mixing. Even though the orifice  56  is slightly tapered, the transition between the orifice  56  and the radially extending downstream wall  61  of the flange  36  has the effect of creating slight vortices or eddy currents that expand outward from the outer edges of the orifice  56  within the fluid in the mixing chamber  60 . These vortices create turbulence and shear within the fluid in the mixing chamber  60  to contribute to mixing. 
         [0050]    The downstream end of the mixing chamber  60  is closed by a flow reducer  62  from which a small tube  64  extends downstream, as shown in  FIGS. 2 and 3 . A pair of rods  66  are attached to the flow reducer  62  at diametrically opposite edge positions at the outer periphery of the flow reducer  62 . The rods  66  extend along an inner surface of the housing  22  within the cavity  24  in an upstream direction within the mixing chamber  60 . The upstream end of the rods  66  contact the wall  61  of the flange  36  within the mixing chamber  60 . The rods  66  space the reducer  62  from the flange  36  and thereby establish the longitudinal dimension of the mixing chamber  60  between the flow reducer  62  and the downstream wall  61  of the flange  36 . 
         [0051]    An upstream surface  67  of the flow reducer  62  is generally funnel or frustoconical shaped. The frustoconically shaped surface  67  tapers or converges inward in the downstream direction to force the fluid in the relatively larger diameter mixing chamber  60  into the relatively smaller diameter tube  64 . As the fluid flows along the frustoconically shaped surface  67 , its pressure increases and its flow rate increases, thereby creating turbulence and shear effects which further contribute to mixing. The transition from the frustoconically shaped surface  67  into the tube  64  also creates turbulent flow which further contributes to mixing. 
         [0052]    The tube  64  projects downstream into a second mixing chamber  68 , relative to a downstream radially extending wall  69  of the flow reducer  62 . The mixing chamber  68  is defined by the substantially larger diameter of cavity  24  of the housing  22 . The transition from the tube  64  to the mixing chamber  60  is abrupt and substantial, which creates an abrupt and substantial pressure drop and an abrupt and substantial reduction in the flow rate, both of which induce considerable turbulence and shear in the fluid within the mixing chamber  68 . The turbulence and shear substantially contributes to further mixing. 
         [0053]    In addition, the extension of the tube  64  into a downstream position into the mixing chamber  68  creates vortices and eddy currents which expand radially outward and possibly even upstream from the downstream end of the tube  64  within the mixing chamber  68 . These vortices and eddy currents create substantial turbulence and shear effects within the fluid in the mixing chamber  68 , and they contribute significantly to the amount of mixing achieved. These vortices and eddy currents exist principally because of the substantial difference in flow rate of the fluid exiting the tube  64  and the considerably slower moving volume of the fluid elsewhere within the mixing chamber  68 . 
         [0054]    A first upstream baffle plate  70   a  interacts with the turbulent flow of the combined fluid leaving the mixing chamber  68 . The baffle plate  70   a,  as shown in  FIG. 6 , as formed by a solid disk  71  which has been cut diametrically on opposite sides almost to its center, to form two half sectors  73 . Diametrically opposite end portions  72  of each half sector  73  are bent in respectively opposite directions. Furthermore, the end portions  72  of the adjoining half sector  73  are bent in respectively opposite directions. The bent portions  72  function as flow deflectors and are referred to as wing portions. 
         [0055]    The bent wing portions  72  provide spaces for the flow through the baffle plate  70   a.  The bent wing portions  72  also act as vanes to induce an upstream, downstream and radial movement of the fluid passing through the spaces between the bent wing portions  72 . The upstream, downstream and radial movement of the fluid passing through the spaces between the bent wing portions  72  is complex in its flow pattern, and that complex flow pattern creates multiple instances or zones of fluid shear and turbulence which contributes substantially to further subdividing the volumetric quantities of the added input fluid within the carrier fluid, as well as substantially dispersing the small volumetric quantities of the added input fluid within the carrier fluid. 
         [0056]    The baffle plate  70   a  is substantially identical to multiple other winged baffle plates  70   b - 70   g  which are spaced in the sequence along the cavity  24  of the housing  22 , downstream of the first upstream baffle plate  70   a.  In each subsequent downstream baffle plate, the space provided between the adjacent bent wing portions  72  is rotated 90° relative to the preceding and subsequent baffle plates, as shown in  FIG. 3 . With the spaces between the bent wing portions  72  rotated in this manner, the fluid flows between the baffle plates with a reversing rotational movement while being divided. This rotational and dividing fluid movement induces further complexity into the pattern of flow diversions which contributes significantly to the dispersal of the volumetric quantities of the added input fluid  14  within the carrier fluid  12 . 
         [0057]    The rods  66  also extend downstream from the flow reducer  62  and connect to the edge of the winged baffle plate  70   a  at diametrically opposite positions, and also connect to an upstream circular support plate  74   a  at diametrically opposite positions. The rods  66 , which extend along the edges of the flow reducer  62  to the upstream baffle plate  70   a  and the upstream support plate  74   a,  hold the first baffle plate  70   a  and the circular support plate  74   a  in position relative to the flow reducer  62 , as well as in a fixed relationship within the cavity  24 . 
         [0058]    The upstream circular support plate  74   a  has substantial openings  76  formed therethrough, as shown in  FIG. 3 . The openings  76  allow the fluid to pass through the support plate  74   a.  Although the openings  76  are substantial in size, they nevertheless create a slight restriction to the flow of the fluid mixture  16 , which slightly changes the pressure and flow velocity as the fluid moves through the openings  76 , which further contributes to the complex pattern of the turbulent flow and the mixing. 
         [0059]    The upstream support plate  74   a  is substantially identical to middle and downstream circular support plates  74   b  and  74   c,  respectively. A center rod  78  connects at the axial center of the upstream winged baffle plate  70   a  and extends downstream through the center of the upstream circular support plate  74   a.  The center rod  78  continues downstream from the upstream support plate  74   a  to connect to the axial center of the winged baffle plates  70   b,    70   c  and  70   d,  and then to connect to the axial center of the middle circular support plate  74   b.  From the middle circular support plate  74   b,  the center rod  78  continues downstream to connect to the axial centers of the winged baffle plates  70   e,    70   f  and  70   g,  and then the center rod  78  terminates at a connection to the axial center of the downstream circular support plate  74   c.  The edge connection of the rods  66  to the winged baffle plate  70   a  and the circular support plate  74   a,  and the connection of the center rod  78  between the baffle plates  70   a - 70   g  and the support plates  74   a - 74   c,  hold together the entire assembly of baffle plates  70   a - 70   g,  the support plates  74   a - 74   c,  and the reducer  62 , thereby forming the main mixing assembly  30 . 
         [0060]    An O-ring  80  is located in an annular groove  81  in the outer periphery of the center support plate  74   b.  The O-ring  80  is slightly compressed between the groove  81  and the inner surface of the cavity  24  of the housing  22 . The slightly compressed O-ring  80  forms a seal and has the effect of diverting any thin stream of laminar combined fluid flowing along the inner surface of the cavity  24  through the openings  76  in the center support plate  74   b.  Any thin stream of laminar fluid flow which may attempt to move along the inner surface of the cavity  24  in the small clearance between the radially outside edges of the winged baffle plates  70   a - 70   d  and the upstream support plate  74   a  is terminated and forced into the main flow by the effect of the O-ring  80 . Preventing the laminar surface flow along the inner surface of the cavity  24  in this manner helps ensure that all of the fluid flowing through the cavity  24  is mixed by the abrupt pressure drops and velocity changes and flow deflections which induce the turbulence and shear forces that cause effective mixing. 
         [0061]    The main mixing assembly  30  is inserted into the cavity  24  at the downstream end of the housing  22 . The main mixing assembly  30  is secured within the cavity  24  by a threaded retention ring  82  which screws into internal threads of a coupling  84  which is hermetically attached to the downstream end of the housing  22 , preferably by welding. The ring  82  abuts against the downstream support plate  74   c,  forcing the the upstream end of the rods  66  to abut against the downstream wall  61  of the flange  36 . In this manner, the ring  82  fixes the position of the main mixing assembly  30  within the cavity  24  and thereby establishes the size, orientation and configuration of the turbulence-inducing components of the main mixing assembly  30 . As an alternative to the threaded retention ring  82 , a snap ring may be expanded into an internal groove (neither shown) to hold the main mixing assembly  30  in the cavity  24 . 
         [0062]    A flow reducer  86  of the output portion  31  of the static mixer  10  is also threaded into the internal threads of the coupling  84 , as shown in  FIG. 2 . An inside surface  88  of the flow reducer  86  is frustoconically shaped or tapered to converge in the downstream direction from the inside diameter of the retention ring  82  to the inside diameter of the outlet conduit  32 . The outlet conduit  32  is preferably integrally formed as a portion of the reducer  86 , or alternatively may be formed as a separate conduit which is inserted into and fixed to the flow reducer  86 . The frustoconically shaped tapered surface  88  increases the speed of the fluid as it exits the cavity  24  of the main mixing portion  19  as the output fluid mixture  16  exits the static mixer  10  through the outlet conduit  32 . The frustoconically shaped tapered surface  67  thereby creates slight additional shear forces which assist in further mixing. 
         [0063]    A perforated plate  90  is held in position between the downstream end of the retention ring  82  (or the alternative snap ring) and the upstream end of the flow reducer  86 . The perforated plate  90  is similar in configuration to the perforated plate  52  ( FIG. 4 ). The fluid flow through holes (not shown) in the perforated plate  90  creates pressure and velocity changes in the fluid, which induces turbulence as the flow moves through the perforated plate  90  into the area defined by the frustoconically shaped surface  88 , before the flow moves into the outlet conduit  32 . 
         [0064]    Some of the specific components of the static mixer  10  described above may be replaced by alternatives to those components. The alternatives may prove beneficial for mixing different types of carrier fluids  12  with different types of added input fluids  14 . 
         [0065]    One alternative  20 ′ of the injector body  20  ( FIGS. 2 and 4 ) is shown in  FIG. 7 . The injector body  20 ′ has a high volume intellect chamber  94  that accommodates a relatively greater volumetric quantity of the carrier fluid  12 . One or more relatively larger injection nozzles  96  extend into the inlet chamber  94 . Each injection nozzle  96  is formed as a small conduit which has been bent to extend an axial portion  98  forward or upstream into the fluid flow through the chamber  94 . The axial portion  98  of the injection nozzle  96  terminates either an open end or in a spray nozzle head (not shown). A larger amount of flow of the added input fluid  14  can be accommodated, or due to the larger volume of the chamber  94 , a longer dwell time for mixing the added input fluid  14  to the carrier fluid  12  is achieved. 
         [0066]    If a single injection nozzle  96  is used, its axial portion  98  will usually be located approximately at the transverse center of the chamber  94 . If multiple injection nozzles  96  are employed, the axial portions  98  of those nozzles  96  are usually distributed at uniform relative positions within in the chamber  94  to disperse the added input fluid  14  uniformly within in the chamber  94 . Because of the larger volume of the chamber  94 , there is a greater pressure drop and velocity decrease within the chamber  94 , compared to the smaller chamber  44  of the injector body  20  ( FIGS. 2 and 4 ), thereby securing greater turbulence and shear flow within the injector body  20 ′. 
         [0067]    A second alternative  20 ″ of the injector body  20  ( FIGS. 2 and 4 ) is shown in  FIG. 8 . The injector body  20 ″ is formed as an internal venturi  102 . The inlet of the venturi  102  is the same as the inside diameter of the inlet conduit  18 , and the outlet diameter of the venturi  102  is the same diameter as the inlet diameter of the orifice  56 . The flow of fluid through the venturi  102  creates a low pressure area in a neck area of the venturi  102 . A nozzle  104  is oriented to open perpendicularly to the reduced pressure fluid flow through the neck of the venturi  102 , to take maximum advantage of the low pressure created by the increased velocity of the carrier fluid through the reduced diameter or neck portion of the venturi  102 . The low pressure in the neck of the venturi  102  helps draw the added input fluid  14  into the carrier fluid  12 . The injector body  20 ″ is useful in adding viscous input fluid  14  to the carrier fluid  12 . 
         [0068]    An alternative to the winged baffle plates  70   a - 70   g  and the support plates  74   a - 74   c  is a reversing, helically-spiraled baffle plate assembly  108 , shown in  FIG. 9 . The helically spiraled baffle plate assembly  108  is formed by a series of connected-together, helically twisted baffle plates  110  and  112 . In the in the example of the reversing, helically-spiraled baffle plate assembly  108  shown in  FIG. 9 , three helical baffle plates  110  and  112  form the assembly  108 . In actuality, many more baffle plates  110  and  112  will typically be used in forming the assembly  108 . 
         [0069]    Each baffle plate  110  and  112  has been twisted in a helically spiraled manner through one half of a complete revolution. As such, a rearward or trailing edge  114  of each helical baffle plate  110  and  112  has been rotated 180° relative to a forward or leading edge  116  of that same helical baffle plate. Each helical baffle plate  110  and  112  therefore assumes a 180° spiral helix configuration. 
         [0070]    The direction of the helical spiral of each subsequent helical baffle plate in the assembly  108  is reversed relative to its preceding and its subsequent helical baffle plates. In the assembly  108  shown in  FIG. 9 , the direction of the helical spiral of the first and third (as shown) helical baffle plates  110  is clockwise (as shown) and reversed from the counterclockwise (as shown) direction of the helical spiral of the next sequential helical baffle plate  112 . Arranged in this manner, each sequential helical baffle plate  110  and  112  rotates the fluid flowing over it in the opposite direction compared to the rotational direction of the preceding and following helical baffle plates. 
         [0071]    The trailing edge  114  of the leading helical baffle plate is connected at  118  to the leading edge  116  of the next subsequent or downstream helical baffle plate. The connection  118  occurs at the transverse centers of the trailing and leading edges  114  and  116 , preferably by welding the helical baffle plates together at the center locations  118 . 
         [0072]    Furthermore, the connection of the adjoining helical baffles plates at the trailing and leading edges  114  and  116  establishes the trailing edge  114  of the upstream helical baffle plate in a generally perpendicular position relative to the leading edge  116  of the downstream helical baffle plate. Arranged in this manner, the fluid flow delivered from one side of the preceding helical baffle plate is divided into two parts by the subsequent helical baffle plate. One part of the divided-out fluid flow from one side of the preceding helical baffle plate is combined with one part of the fluid flow from the other side of the preceding baffle plate. Each subsequent helical baffle plate divides and combines the flow parts in this manner on a continuous basis. Such continual division and recombination achieves uniform dispersion. 
         [0073]    A complex pattern of pressure changes and velocity changes accompanies these flow rotations, flow reversals, flow divisions and flow recombinations. This complex pattern of flow deflections induces turbulence and shear effects within the fluid flow to promote thorough and homogeneous mixing as the flow moves through the connected series of helically twisted baffle plates  110  and  112  of the assembly  108 . 
         [0074]    The static mixer  10  achieves improved mixing or dispersion by use of multiple different types and configurations of structural mixing elements. The structural mixing elements achieve both a uniform dispersal of the added input fluid within the carrier fluid and also effectively subdivide the added input fluid into very small volumetric quantities which are then uniformly dispersed within the carrier fluid, to achieve a very homogeneous output fluid mixture. 
         [0075]    As an Example of the effectiveness of the static mixer, a mixer having the configuration shown in  FIGS. 1 and 2  was used to create an emulsion of approximately 1 quart of conventional 30 weight motor oil with approximately 100 gallons of water. The entire 100 gallons of water was pumped through the static mixer in approximately 2 minutes. The entire quart of motor oil was added in a single pass of the 100 gallons of water passed through the static mixer, to form a water-oil emulsion. The water and the motor oil distributed in it were delivered into a tank, and the degree of natural separation of the oil and water was observed visually over time. The quality or degree of emulsification of the water and oil was judged by the amount of time required for the oil and water to separate out of the emulsion and recombine. A minute observable separation of the oil and water occurred after about 24 hours, and after approximately 72 hours, a significant amount of oil still remained suspended in emulsion. These observations were judged to indicate a very high quality and degree of emulsification of the oil in the water. 
         [0076]    The relatively long amount of time during which the oil remained dispersed and emulsified within the water indicates a high degree of mixing and a high degree of subdivision of the volumetric quantities of oil into much smaller volumetric quantities that were evenly dispersed within the mixture. A lesser degree of dispersion and subdivision would have resulted in a considerably shorter amount of time to observe the separation. 
         [0077]    In addition to the beneficial improvement of more thorough mixing and subdivision of the added inlet fluid, the more thorough mixing and dispersion is achieved, while still preserving enough input energy to allow the output fluid mixture  16  to be used in many industrial applications without additionally pumping it, such as spraying or coating. To illustrate this aspect, in the Example of creating the emulsion of water and oil, described above, the pressure of the input water supplied to the static mixer was approximately 58 pounds per square inch, and the pressure of the output fluid mixture of the emulsified water and oil leaving the mixture was approximately 16 pounds per square inch. The 16 pound per square inch outlet pressure is sufficient to apply the output fluid mixture for many industrial applications, without additionally raising its pressure by subjecting it to further pumping. 
         [0078]    The type, organization and arrangement of the structural mixing elements results in a relatively compact sized static mixer which can be used in a variety of new and retrofit applications. In the Example described above of mixing oil with water, the mixer is approximately 28 inches long between the inlet conduit and the outlet conduit. The mixer weighs approximately 24 pounds when made from steel. The outside diameter of the housing  22  is less than 5 inches. The static mixer is compact enough to be easily portable to onsite locations at which fluids are desired to be mixed immediately prior to use of the mixed fluids. 
         [0079]    The static mixer is easily manufactured and assembled due to the modular nature of the main mixing assembly  30 , and the ability to insert and withdraw that main mixing assembly from within the cavity  24  of the housing  22  by the removable retention ring  82  and output flow reducer  86 . Consequently, it is relatively easy to assemble and replace any of the components of the main mixing assembly  30 , if necessary or desirable. The static mixer  10  is also relatively inexpensive to construct and operate compared to similar known static mixing devices. 
         [0080]    Many other advantages and improvements will become apparent upon fully appreciating the significant aspects of the present invention. Presently preferred embodiments of the present invention and its many improvements have been described with a degree of particularity. This description is of preferred examples of implementing the invention, and is not necessarily intended to limit the scope of the invention. The scope of the invention is defined by the scope of the following claims.