Abstract:
A diffuser for use in a pressurized feed system. The diffuser introduces a carbonic acid solution into water to be treated. The carbonic acid solution within the diffuser is maintained at an elevated pressure. As the carbonic acid solution passes to the exterior of the diffuser, the pressure drop causes an effective mixing of the carbonic acid solution and the water. The carbonic acid solution mixes with the water and the pH of the water is reduced.

Description:
RELATED APPLICATION 
     This application is a divisional of U.S. Ser. No. 09/848,626, filed May 3, 2001 entitled “DIFFUSER FOR USE IN A CARBONIC ACID CONTROL SYSTEM” now U.S. Pat. No. 6,568,661 which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to pressurized feed systems to treat water and, more particularly, relates to introducing CO 2  into the water to reduce the pH. 
     BACKGROUND OF THE INVENTION 
     Raw water may be treated by any number of ways to obtain a final treated water product. However, the final treated water product may have a pH level unsuitable for commercial or consumer requirements. Typically, a final treated water product requires a pH level of less than 9. One method for lowering the pH level in water is to inject CO 2  into the water by a direct gas feed system. The CO 2  is passed through a diffusion system in a recarbonated basin. This diffusion system is commonly referred to as a bubbler. Another method for injecting carbon dioxide into water is to aspirate the carbon dioxide with a venturi. An apparatus using a venturi is sometimes also referred to as a diffuser. 
     In either method of introducing CO 2  into water, the CO 2  is introduced into a carrier solution to form a carbonic acid solution. To keep the CO 2  in solution and prevent the formation of gas bubbles in the system, the carbonic acid solution is maintained at an elevated pressure. Diffusers are engineered to maintain the system pressure and to distribute the carbonic acid solution into the water being treated. As the pressurized carbonic acid solution is introduced into the water being treated, the CO 2  expands and is released and mixed into the stream of water. 
     An example of a known diffuser is disclosed in my U.S. Pat. No. 5,487,835, the entire disclosure of which is incorporated herein by reference. In my &#39;835 patent, the diffuser  71  has three rectangular sides defining a triangular prismatic structure. The diffuser  71  is inserted normal to the direction of flow of the water stream. The carbonic acid solution is passed through one end of the diffuser  71 . While the carbonic acid solution is within the diffuser  71 , the diffuser  71  maintains the elevated pressure of the carrier solution forcing the formation of carbonic acid and excess CO 2 , if any, to remain in the carbonic acid solution. 
     The diffuser  71  has a plurality of outlet holes on two of the rectangular sides. The plurality of holes face upstream while the third rectangular side faces down stream. The passing of the carbonic acid solution through the plurality of holes forces the CO 2 , if any, to be released into the stream of water to reduce the pH. The downstream positioning of the third side without the holes creates a vortex in the stream of water which creates additional mixing. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus for adjusting the pH of water using a carbonic acid solution. The diffuser of the present invention maintains the system back pressure when processing the carbonic acid solution and dispenses the CO 2 , if any, to adjust the pH of the water being treated. 
     In one embodiment of the present invention, the diffuser includes an injector for injecting the carbonic acid solution into a receiver tank. Centrally located within the interior of the receiver tank is a driven impeller. The injector directs the carbonic acid solution towards the impeller. The rotation of the impeller causes the carbonic acid solution and the water within the receiver tank to commingle. 
     According to another embodiment of the invention, a diffuser of the present invention includes an annular cylinder with a hollow formed therein. A solution inlet permits carbonic acid solution into the annular cylinder. The annular cylinder defines an interior path leading from the inlet, through the hollow, and back to the inlet. A plurality of outlet holes are formed in an upper side of the annular cylinder. The outlet holes permit the carbonic acid solution to flow from the hollow to the exterior of the annular cylinder. 
     In still another embodiment of the present invention, a diffuser of the present invention includes an elongated body having a hollow therethrough. One end of the elongated body includes an end plate over the hollow. The end plate defines an obround outlet for permitting carbonic acid solution to pass into the water to be treated. The obround outlet is shaped to direct the solution in a particular manner. 
     In yet another embodiment of the present invention, a diffuser of the present invention includes a pair of laterally displaced nozzles. The pair of nozzles extend into a mixing cylinder and are fixed in a stationary position. The nozzles are oppositely-oriented relative to one another to direct carbonic acid solution passing through each of the nozzles in opposite directions which causes the water and the solution to circulate in the mixing cylinder. 
     The foregoing has broadly outlined some of the more pertinent aspects and features of the present invention. These should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Other beneficial results can be obtained by applying the disclosed information in a different manner or by modifying the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding of the invention may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings, in addition to the scope of the invention defined by the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a front view of one embodiment of a diffuser assembly of the present invention having an injector for directing solution at an impeller. 
     FIG. 2 is a close-up view of the injector of FIG.  1 . 
     FIG. 3 illustrates a top view of another embodiment of the present invention having an annular cylinder with a plurality of outlet holes formed in an upper side of the annular cylinder. 
     FIG. 4 is a side view of the diffuser shown in FIG.  3 . 
     FIG. 5 is a front view of another embodiment of a diffuser of the present invention having an elongated hollow body, with an obround outlet at one end, positioned within a T-shaped pipe section. 
     FIG. 6 illustrates a cross-sectional view taken along the line A—A of FIG.  5 . 
     FIG. 7 illustrates a side view of another embodiment of a diffuser of the present invention having a pair of laterally displaced nozzles adapted to be positioned in a fixed manner in a mixing cylinder. 
     FIG. 8 illustrates a bottom view of the diffuser of FIG.  7 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings in which like numerals indicate like elements throughout the several views, the drawings illustrate exemplary embodiments of the present invention. 
     In FIG. 1, a diffuser assembly  10  includes an injector  12  for use with a receiver tank  16 . The receiver tank is also commonly referred to as a mixing tank  16 . Within the receiver tank  16  is a motor driven impeller  14 . The injector  12  and impeller  14  are preferably made of type  304  stainless steel. Preferably, a pair of injectors  12  are used with a pair of receiver tanks  16  in a single operation. The injectors  12  in the receiver tanks  16  are assembled alongside one another and operate in a toggling manner. One injector  12  in one receiver tank  16  processes water while the second injector  12  in the second receiver tank  16  is temporarily isolated. 
     As shown in FIG. 2, the injector  12  includes an elongated member  20  having a solution inlet end  22  and a solution outlet end  24 . The outlet end  24  includes a pair of aligned concentric reducers  26  and  28 . The inner diameter of the narrower reducer  28  is preferably approximately {fraction (33/64)} inches, but may be varied according the specifications of the impeller  14  and the receiver tank  16 . Preferably, the pressure drop through the injector  12  is approximately 44 to 55 psi. An additional reducer, such as concentric reducer  30  may also be used as part of the injector  12 . The bores of each of the reducers  26 ,  28  and  30  are aligned with one another to permit each reducer to cooperate with one another to direct the flow of solution through the injector  12  into a stream generally directed at the impeller  14 . 
     The injector  12  further includes an outwardly extending flange member  32  spaced between the inlet and outlet ends  22 ,  24  which is used to connect the injector  12  to the receiver tank  16  as explained below. The diffuser assembly  10  also includes an injector support  34  having an concentric collar  36  configured to surround a mid-portion of the injector  12  and a second outwardly extending flange member  38  mounted to the collar  36 . The injector  12  is adapted to be received in an opening in the side wall of the receiver tank  16  to permit the solution to pass from the exterior to the interior of the receiver tank  16 . The flange member  32  of the injector  12  and the flange member  36  of the injector support  34  abut against one another to retain the injector  12  in the receiver tank  16 . Preferably, the injector  12  is tapped into the side wall of the receiver tank  16 . 
     The impeller  14  is multi-vaned and is centrally supported within the receiver tank  16  on a distal end  40  of a drive shaft  42 . The drive shaft  42  is coupled to an electric motor which drives the impeller  14 . The vanes of the impeller are oriented to rotate generally about the centerline of the receiver tank  16 . The radial-length of each of the vanes is preferably substantially smaller than the radius of the receiver tank  16 . A proximal end  44  of the drive shaft  42  is supported through the top of the receiver tank  16  by inlet assembly  46 . The injector  12  is positioned in the side wall such that the longitudinal center line of the injector  12  is approximately aligned with the distal end  40  of the drive shaft  42 . 
     During operation of the diffuser assembly  10 , the water is received into the receiver tank  16  through inlet assembly  46 . Concurrently, the injector  12  injects the carbonic acid solution into the receiver tank  16 . As the water accumulates in the receiver tank  16 , the carbonic acid solution from the injector  12  is aimed at the rotating impeller  14 . The rotation of the impeller  14  causes the solution and the water to be commingled. As the solution and the water is commingled, the carbonic acid with excess CO 2 , if any, mixes with the water, thus reducing the pH of the water in the receiver tank  16 . 
     As shown in FIGS. 3 and 4, another diffuser  50  of the present invention is shown. The diffuser  50  is for use within a mixing chamber  54  and includes an annular cylinder  52  having a hollow therethrough. A carbonic acid solution inlet  56  is attached to a portion of the exterior circumference of the annular cylinder  52 . The cylinder  52  and solution inlet  56  are preferably made of type  304  stainless steel. The cylinder  52  defines an interior path from the solution inlet  56 , through the hollow, and back to the solution inlet  56 . 
     The cylinder  52  is oriented in the bottom of the mixing chamber  54  to permit the flow of excess CO 2  upward to the top of the mixing chamber  54 . Preferably, the CO 2  flows upward along substantially the entire height of the mixing chamber  54 . Elongated mounting members  58  act as legs to support the cylinder  52  and extend from an underside  68  of the cylinder  52 . Preferably, the elongated mounting members  58  are spaced equidistant apart from one another as best shown in FIG.  3 . At distal ends  60  of the elongated members  58  are mounting plates  62  for mounting the diffuser  50  with fasteners (not shown) to a surface within the mixing chamber  54 . The mounting plates  62  are also best shown in FIG.  3 . The elongated members  58  and mounting plates  62  are also preferably made of type  304  stainless steel. 
     An upperside  64  of the cylinder  52  includes a plurality of outlet holes  66 . The outlet holes  66  are preferably spaced equidistant apart and allow the carbonic acid solution to pass from the hollow of the cylinder  52  to the exterior of the cylinder  52  in an even manner. 
     In operation, the carbonic acid solution is pumped under pressure into the cylinder  52  through the solution inlet  56 . The carbonic acid solution circulates under pressure through the entire length of the path through the hollow. As the carbonic acid solution circulates, portions of the carbonic acid solution pass through the outlet holes  66  in the upperside  64  of the cylinder  52 . As the carbonic acid solution passes through the outlet holes  66 , the pressure of the carbonic acid solution drops causing excess CO 2 , if any, to be forced from the carbonic acid solution. Preferably, the pressure drop is approximately 45 to 55 psi. The carbonic acid solution mixes with the water being treated in the mixing chamber  54 . 
     FIGS. 5 and 6 illustrate another diffuser  70  of the present invention intended for use with the dirtiest water. The diffuser  70  is preferably used in combination with a T-shaped pipe section  72 . The diffuser  70  also defines a hollow and includes an elongated body  74  having first and second ends  76  and  78 , respectively. An end plate  80  is fastened with fasteners (not shown) or welded to the second end  78  of the elongated body  74 . A front view of the end plate  80  is shown in FIG.  6  and is described in greater detail below. The elongated body  74  and the end plate  80  are preferably made of type 304 stainless steel. 
     The T-shaped pipe section  72  includes a cross-through portion  82  and a leg portion  84 . The cross-through portion  82  is also typically referred to as the top horizontal portion of a traditionally oriented letter “T”. The leg portion  84  is then the vertically oriented portion of the letter “T”. However, as shown in FIG. 5, the T-shaped pipe section  72  is set on its side and the leg portion  84  is then horizontally oriented. 
     In FIG. 5, the water being treated is represented by the arrow adjacent the reference letter W. This arrow indicates that the water W is passing through the cross-through portion  82  from a first end  86  to a second end  88  of the T-shaped pipe section  72 . The diffuser  70  is secured at least partially within the hollow portion, on the center line, in the leg portion  84  of the T-shaped pipe section  72  such that the second end  78  of the elongated body  74  of the diffuser  70  is oriented toward the cross-through portion  82 . In FIG. 5, a pair of mounting flanges  90  on the leg portion  84  abut a pair of mounting flanges  92  surrounding the diffuser  70 . Fasteners (not shown) are used to secure the two sets of mounting flanges  90 ,  92  together. 
     As best shown in FIG. 5, the second end  78  of the elongated body  74  of the diffuser  70  is truncated. The second end  78  is truncated to orient the solution passing through the end plate  80  generally counter to the direction of flow through the cross-through portion  82  of the water being treated. However, in some cases, the end plate  80  may be oriented to direct the carbonic acid solution in the same direction as water W. For example, in FIG. 5, there is approximately a 30 degree angle between a vertical line (not shown) passing through the forward tip of the second end  78  and the end plate  80 . This angle may be anywhere in the range of approximately 20 to 45 degrees. The second end  78  should not be parallel to a circle defined by a plane  94  intersecting the hollow in the leg portion  84  of the T-shaped pipe section  72 . Three reference arrows are shown in FIG. 5 to indicate the general direction of the flow of solution from the end plate  80  of the diffuser  70 . 
     FIG. 6 illustrates a view of the end plate  80  taken along line A—A in FIG.  5 . The outer circumference of the end plate  80  is configured to conform to the second end  78  of the elongated body  74 . The end plate  86  itself defines an obround outlet  98  therethrough. As used herein, the term “obround” means having at least two generally parallel or curved sides  100  and generally semicircular ends  102 , quarter rounded ends, or curved corners. In other words, obround means having periphery segments with rounded intersections. The periphery segments on adjacent sides have unequal lengths, but the periphery segments which oppose one another are generally parallel and are of equal length. The term is thus intended to encompass closed figures having generally opposite sides with rounded corners, generally elliptical closed figures, and generally rectangular closed figures having rounded corners, for example quarter rounded corners. Accordingly, the term obround is meant to be interpreted broadly to cover shapes having cross sections that are generally rectangular, generally elliptical, or generally obround, but have rounded corners to facilitate fluid flow therethrough as described herein. 
     The obround outlet  98  is larger than the size of an outlet  66 , described above, because the diffuser  70  is intended for use with dirtier water. As explained above, the obround outlet  98  directs the carbonic acid solution passing therethrough into a direction different from the path the solution had taken upon entering the diffuser  70 . In particular, the solution upon passing through the obround outlet  98  is directed counter to the direction of the water W passing through the cross-through portion  82  of the T-shaped pipe section  72 . As before, the carbonic acid solution enters the diffuser  70  under pressure, maintaining the CO 2  in the carbonic acid solution. As the carbonic acid solution emerges from the obround outlet  98 , the resulting pressure differential effectively mixes the carbonic acid solution with the main water stream. Preferably, the pressure drop is approximately 45 to 55 psi. The excess CO 2  is released in generally a direction counter to the direction of the water W. The pH of the water passing through the cross-through portion  82  is reduced as a result of the introduction of the carbonic acid solution. 
     FIGS. 7 and 8 illustrate yet another diffuser  110  of the present invention. The diffuser  110  includes a pair of nozzles  112  laterally displaced from one another. The pair of nozzles  112  extend into the interior of a mixing cylinder (not shown) which is used for receiving the carbonic acid solution from the diffuser  110  and the water to be treated. An elongated body  114 , having first and second ends  116  and  118 , extends the pair of nozzles  112  into the mixing cylinder. The elongated body  114  includes a hollow therethrough for carrying the carbonic acid solution to the pair of nozzles  112 . The nozzles  112  extend from the second end  118  in substantially a perpendicular manner and remain fixed in a stationary position within the cylinder. The pair of nozzles  112  do not rotate about a central axis of the elongated body  114 . Distal ends  120  of the nozzles are substantially oppositely-oriented relative to one another to direct the solution passing through the nozzles  112  in opposite directions. 
     As best shown in FIG. 8, each nozzle of the pair of nozzles  112  is defined by elbow portions  122  and concentric reducers  124 . In particular, each nozzle includes a pair of elbow portions  122  defining a semicircular portion. At an end of each semicircular portion is a pair of concentric reducers  124  aligned with one another to direct the solution. 
     In the preferred embodiment, the diffuser  110  further includes at least one support member  130  for additional structural support within the mixing cylinder and to prevent torque created by the pair of nozzles  112  from twisting the elongated body  114  from the top of the mixing cylinder. In FIG. 7, a pair of support members  130  extend downward from the pair of nozzles  112  and the second end  118  of the elongated body  114 . A mounting flange  132  is then used to secure the support members  130  to the bottom of the mixing cylinder. 
     In operation, the carbonic acid solution coming from the pair of nozzles  112  causes the water and the carbonic acid solution to circulate in the mixing cylinder. Moreover, the carbonic acid solution enters the diffuser  110  under pressure and, as the solution passes through the pair of nozzles  112 , the pressure differential causes excess CO 2  in the carbonic acid solution to burst forth. Preferably, the pressure drop is approximately 45 to 55 psi. The circulating of the carbonic acid solution with the water caused by the pair of nozzles  112 , as well as the excess bubbles of CO 2  bursting forth, if any, results in the commingling of the carbonic acid solution and the water. The commingling of the carbonic acid solution, excess CO 2  and the water reduces the pH in the mixing cylinder. 
     In any embodiment of the present invention, the amount of CO 2  which can be mixed with the stream of water or a container of water to be treated at various temperatures and pressures is dependent on the performance characteristics of the CO 2  supply, the carbonic acid solution supply, and in particular, the performance characteristics of each of the diffusion systems as described above. 
     The present invention has been illustrated in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will recognize that the present invention is capable of many modifications and variations without departing from the scope of the invention. Accordingly, the scope of the present invention is described by the claims appended hereto and supported by the foregoing.