Abstract:
Apparatus and methods for treatment of liquids by generating hydroxyl radicals through the dissolution of water molecules by hydraulic cavitation.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to apparatus and methods for effecting the dissolution of water into hydroxyl radicals for the treatment of liquids. 
       BACKGROUND OF THE INVENTION 
       [0002]    Centrifugal separation of solids carried in a liquid-solid suspension by hydrocyclonic technology involves tangentially feeding the suspension into an open-ended, circular cylinder having an inwardly tapering inner diameter and extracting from its apex heavier solids, while collecting finer solids from its larger opposite end. Individual hydrocyclone cylinders may be relatively small—on the order of about four inches in length and with an inner diameter tapering from about a half inch to about a tenth of an inch—and are generally referred to as cyclonettes. 
         [0003]    Typically, the cyclonettes are grouped in a housing, as shown in U.S. Pat. Nos. Re. 25,099; 3,261,467; 3,415,374; 3,486,618; 3,598,731; 3,959,123 and 5,388,708. As indicated by these patents, this technology dates back to at least the mid-1950&#39;s. Regardless, the essence of the technology is the same. A spiral flow of the suspension is introduced tangentially along the inwardly tapering inner wall of the cyclonette near its wider end and flows along the inner wall toward the opposite, smaller end. This generates a counter flow, which carries fines out the larger, open end. 
         [0004]    In contrast to hydrocyclonic technology, hydraulic cavitation is directed toward the dissolution of water into hydroxyl radicals for the treatment of liquids. Early work in this field was directed to the generation of hydraulic cavitation by means of sound waves. See, for example, “The Chemical Effects of Ultrasound,” by Kenneth S. Suslick,  Scientific American , February, 1989, pp. 80-86. However, hydraulic cavitation may also be induced by cavitating jets. See “Remediation and Disinfection of Water Using Jet Generated Cavitation,” by K. M. Kalumuck, et. al., Fifth International Symposium on Cavitation (CAV 2003) Osaka, Japan, Nov. 1-4, 2003. 
         [0005]    Regardless of which cavitation method is employed, the goal is to generate many fine bubbles, which upon their implosion, create intense, but highly localized temperatures and pressures. This energy release then causes a dissolution of the water molecules and the creation of free hydroxyl radicals. The potential of these powerful radicals for the beneficial treatment of the water has been well recognized for many years. 
         [0006]    For example, the patent literature discloses a multitude of methods and apparatus for this purpose. See, for example, U.S. Pat. No. 6,200,486, where fluid jet cavitation is employed for the decontamination of liquids by directing the flow along an interior chamber surface. Note also U.S. Pat. No. 6,221,260, which describes the creation of a central vortex about a longitudinal axis for inducing cavitation pockets in the vortex, and U.S. Pat. No. 6,896,819, which relies upon the formation of a liquid vortex along an inner surface of a cyclone. 
         [0007]    Thus, it will be seen that the beneficial effects of cavitation are acknowledged and an understanding of the mechanism involved has been known for decades. However, the inefficiency of the known processes, whether based on ultrasonic or jet cavitation, has restricted commercial acceptance of hydraulic cavitation. There thus remains the apparent conundrum of a highly effective method of water treatment but at an energy cost that thwarts its widespread implementation. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention obviates the inefficiency of present day cavitation processes by employing liquid jets, but in a manner contrary to existing jet cavitation technology. Thus, while conventional wisdom focuses on the formation of hollow core jets to create shear zones that in turn generate cavitation, the present invention, in one embodiment, is directed to the formation of a central axial jet and a vacuum chamber that can be sealed by the exiting jet. Thus, in accordance with the present invention, cavitation is generated by directing a high velocity jet of fluid through a volume of vapor under a vacuum created in the chamber through which the jet travels. 
         [0009]    In this embodiment, the present invention employs a high speed jet of liquid, flowing axially and concentrically through a cylindrical chamber to generate a vacuum within a confined space. The invention includes the provision of a liquid-free volume around the jet near the inlet end of the chamber to cause vapor to accumulate. The discharge opening of the chamber is designed so that it will be completely filled by the exiting jet of fluid, so as to seal the chamber and permit maintenance of a vacuum. 
         [0010]    The present invention recognizes that although hydrocyclone technology is completely alien to hydraulic cavitation, conventional hydrocyclone apparatus may be modified and thus adapted for implementation of the present invention. For example, a conventional cyclonette may be employed to provide a central axial jet with its conventional, tangential feed opening blocked. Additionally, a multiplicity of cyclonettes may be mounted in a housing, essentially as shown in U.S. Pat. No. 5,388,708, but with the cyclonettes fed from the annular, outer chamber and discharging into the inner or central cylindrical chamber. 
         [0011]    Alternatively, the tangentially directed inlet port in the cyclonettes of the &#39;708 patent may be employed to inject a second stream of liquid into the cyclonette along its inside wall in a spiral flow path. Vapor within the cyclonette will tend to be dragged axially toward the discharge end by the linear jet and in a spiral path by the second liquid. When the two high-velocity liquid streams approach one another, the shear created due to the differences in velocity will tend to create a turbulent mixing zone that will disrupt the vapor film between the two liquids and generate bubbles. Increasing the fluid velocities will increase shear and reduce the size of the bubbles. It will also result in increased vacuum within the chamber and the generation of more vapor. 
         [0012]    With this design cavitation initiates at very low inlet fluid pressure—on the order of 10 psi or less, with water at 30° C. and atmospheric pressure discharge. Also, the high shear generated helps reduce bubble size, which in turn, increases bubble surface to volume ratio and improves chemical reaction rates. As long as the velocity head of the fluid exiting the chamber exceeds the static pressure in the discharge zone, a vacuum will be generated within the chamber. Once pressure within the chamber drops to the vapor pressure of the liquid, vapor fills the cavity and cavitation occurs. Thus, the amount of vapor entrained is almost independent of pressure in the discharge zone. 
         [0013]    As a modification of this embodiment, the main inlet jet may pass through a vortex finder of conventional design, except that, in addition to the flow being directed into the cyclonette from the vortex finder (instead of out of the cyclonette through the vortex finder), the vortex finder is modified to impart a spin to the incoming jet in a direction opposite to the direction of the tangential inlet flow. The result is that the collision of the two streams flowing in opposite directions creates a shear on the vapor trapped between the two streams that tears the vapor film into tiny bubbles, leading to increased cavitation efficiency. 
         [0014]    In still a further modification of the basic embodiment of the invention, the enhancement of fine bubble generation may be attained by the interposition in the flow path into the cyclonette of a washer-shaped orifice plate. The abrupt decrease in diameter of the flow path through a modified vortex finder, not only accelerates flow and decreases pressure, but generates an intense shear zone that forms a virtual fog of tiny bubbles, the collapse of which, generates localized extreme temperatures and pressures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is an elevational view, partly in section, displaying an array of cyclonettes modified in accordance with the present invention, to generate hydraulic cavitation; 
           [0016]      FIG. 2  is an elevational view of the extreme lower end of the device of  FIG. 1  and with the cooperating inlet and outlet flow manifolds; 
           [0017]      FIG. 3  is a cross-sectional view of a portion of  FIG. 1  showing in greater detail the positioning of a modified cyclonette; 
           [0018]      FIG. 4  is a horizontal view in cross-section taken along line  4 - 4  of  FIG. 1 ; 
           [0019]      FIG. 5  is a view similar to  FIG. 4 , but with portions removed to show more clearly the physical relationships of modified cyclonettes within an array with respect to each other; 
           [0020]      FIG. 6  is an enlarged cross-sectional view of a cyclonette and vortex finder; 
           [0021]      FIG. 7  is a view similar to  FIG. 6 , but showing a modified cyclonette and a modified vortex finder, together with an orifice plate; 
           [0022]      FIG. 8  is a view similar to  FIG. 7 , but showing the flow of the liquid through the modified cyclonette, vortex finder and orifice plate; 
           [0023]      FIG. 8A  is a somewhat diagrammatic view of the liquid flow at point  8 A in  FIG. 8  and showing individual bubbles generated as the liquid flows through the inlet plate; 
           [0024]      FIG. 8B  is a view similar to  FIG. 8A , but depicting the flow and bubbles at point  8 B in  FIG. 8  of the drawings; 
           [0025]      FIG. 8C  is a view similar to  FIGS. 8A and 8B , but showing the individual bubbles somewhat dispersed at point  8 C in  FIG. 8  downstream of points  8 A and  8 B in  FIG. 8 ; 
           [0026]      FIG. 9  is a view similar to  FIG. 6 , but showing a modified flow path through the body of a cyclonette; 
           [0027]      FIG. 10  is a view similar to  FIG. 9 , but with the extension of the vortex finder removed; and 
           [0028]      FIG. 11  is a view similar to  FIG. 7 , but showing the orifice plate positioned downstream from the position shown in  FIG. 7 , closer to the throat area of the modified cyclonette. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Turning initially to  FIG. 6  of the drawings, a more or less conventional cyclonette  10  is shown with a vortex finder  12  installed in the left hand end of the cyclonette as it appears in  FIG. 6  of the drawings. For a purpose to be presently described, the left-hand end of the cyclonette may be provided with an annular groove  14  into which an O-ring  16  may be seated. To the right of the O-ring  16 , as seen in  FIG. 6  of the drawings, a second annular groove  18  may be formed to receive a second O-ring  20  of more or less rectangular cross-sectional configuration. Interiorly of the cyclonette  10 , a flow path is provided comprising a throat portion  22 , an inwardly tapering flow channel  24 , and a terminal flow channel  26  of narrower constant diameter. At its left-hand end, as seen in  FIG. 6 , the cyclonette  10  may be provided with an internally threaded socket  28  receiving the complementary external threads  30  of the vortex finder  12 . The vortex finder has a uniformly inwardly tapering wall  32  and an extension  34  projecting into the throat portion  22  of the cyclonette. Lastly, the cyclonette may be provided with a passageway  36  extending through a wall of the cyclonette  10  into the throat section  22 . 
         [0030]    With reference now to  FIG. 1  of the drawings, a housing  40  is shown comprising cylinders  42 , each having outwardly projecting annular flanges  44  to permit two or more cylinders  42  to be clamped together by bolts  46  to form a continuous, outer, annular chamber  68 . While three cylinders  42  are shown in  FIG. 1  of the drawings, it will be apparent that more or less cylinders may be employed, depending on the desired length of the annular outer chamber. At its upper end, the annular outer chamber is capped by a closure plate  50  having a lifting ring  52 . The closure plate  50  is clamped to the upper end of the uppermost cylinder  42  in a manner similar to the clamping between adjacent cylinders by means of bolts  46 . 
         [0031]    With reference now to  FIGS. 1 and 2  of the drawings, it will be seen that the lowermost cylinder  42  is attached at its lower end by means of bolts  46  to a manifold system  54 . At its upper end, the manifold system  54  has an outwardly projecting annular flange  56  to which the lower most cylinder  42  is clamped by the bolts  46  as shown in  FIG. 2  of the drawings. The manifold system  54  comprises three concentric flow channels, namely, an outer feed channel  58 , a central, outwardly-flowing channel  60 , and an intermediate channel  62 , which may or may not be used during the practice of the present invention, as will be described in more detail. 
         [0032]    As seen in  FIG. 1  of the drawings, positioned concentrically within the outer cylinders  42  are intermediate cylinders  64  and inner cylinders  66 , which are each superimposed upon each other and clamped by the clamping action between the outer cylinders, the top plate  50  and the lower annular rim  56  of the manifold system  54 . It will thus be apparent with reference to  FIGS. 1 and 2  of the drawings that the outer and intermediate cylinders form the annular outer chamber  68  communicating with the outer feed manifold  58 , an inner or central chamber  70 , communicating with the manifold  60 , and an intermediate chamber  72  communicating with the manifold  62 . 
         [0033]    As best seen in  FIG. 3  of the drawings, adjoining sets of intermediate and inner cylinders may be provided with annular grooves  74  and  76  to receive any convenient sealing means. Intermediate cylinders  64  are also provided with closely spaced openings  78  to receive cyclonettes which may be of more or less conventional design of a type shown in  FIG. 6  of the drawings or of various modified forms which will be described presently in more detail. In any case, the cyclonettes are secured in any convenient manner in the openings  78  with the opposite ends of the cyclonettes being received in openings  80  in the cylinders  66 . In  FIG. 3  of the drawings the openings  78  are shown as having internal threads, which could receive complementary external threads on the exterior of the cyclonettes. In this regard, O-rings, such as those shown at  16  and  20  in  FIG. 6  of the drawings, may be utilized to create seals with the cylinders  64  and  66 , respectively. 
         [0034]    However, the particular manner of securing the cyclonettes in the intermediate and interior cylinders  64  and  66  does not form a part of the present invention, and any convenient means may be utilized. In any case, the positioning of a cyclonette, regardless of its specific configuration, in the manner shown in  FIG. 3  permits the liquid delivered through the outer manifold  58  and into the annular outer chamber  68  to flow into an insert  82  and then into the upstream end of the cyclonette and out its downstream end where it is immersed in the liquid being treated, which is being collected in the inner or central cylindrical chamber  70  and then out through the manifold  60 . 
         [0035]    As seen in  FIGS. 1 and 4  of the drawings, it is contemplated by the present invention that hundreds, perhaps even a thousand or more of cyclonettes, will be arrayed in a single housing  40 . Preferably, each cyclonette, as depicted at  10 ′ in  FIG. 5  of the drawings, is disposed opposite another, resulting in direct impingement of the flow from one cyclonette upon the opposite flow from an opposing cyclonette. 
         [0036]    As indicated, previous, conventional utilization of a cyclonette and vortex finder insert as shown in U.S. Pat. No. 5,388,708, for example, would result in flow, with reference to  FIG. 2  of the drawings, into the intermediate manifold  62  and thence, with reference to  FIG. 1 , into the intermediate chamber  72 . From there the flow would pass into the passageway  36  as seen in  FIG. 6  of the drawings, and then spiral around the surface of the throat  22  and thereafter, around the surface of the tapered flow channel  24  to the right as seen in  FIG. 6  of the drawing. This would set up a counter flow to the left as seen in  FIG. 6  and out the vortex finder  12  of the fines fraction of the suspension while the heavier fractions of the suspension passed on out the narrower flow channel  26  of the cyclonette. 
         [0037]    In contrast, in accordance with the present invention, the feed flow in manifold  58 , as shown in  FIG. 2  of the drawings, is just the opposite of conventional operation. That is, instead of accepting the fines in an outward flow, the manifold  58  is in fact the feed manifold for the system, delivering the liquid to be treated to the upstream or left-hand end of the vortex finder, as shown in  FIG. 6  of the drawings, from whence the flow is ejected in an axial jet out the extension  34  of the vortex finder and into the tapering flow channel  24 . This action results in the generation of shear zones that create a myriad of tiny bubbles, each of which, upon implosion, create highly localized areas of extreme pressures and temperatures. 
         [0038]    This in turn results in a dissolution of the water molecules into, inter alia, aggressive hydroxyl radicals. While in its most straightforward form the passageway  36  in the upstream end of the cyclonette will not be utilized, in a modification of the basic form of the invention, a supply of the liquid being treated may be fed via the intermediate manifold  62  and the intermediate chamber  72  into the passageways  36  to provide an additional flow and hence an intensifying of the shear zone to enhance the formation of the tiny bubbles as liquid flows through the tapering flow channel  24  of the cyclonette  10 . 
         [0039]    Depending upon the desired effect, the passageway  36  may be disposed tangentially with respect to the throat  22 , radially, or even substantially axially. It should also be noted that, in addition to utilizing the passageway  36  for the supplemental flow of the liquid being treated, different fluids, gaseous or liquid, could be injected through the passageway  36  to alter the physical or chemical character of the liquid being treated. For example, a pH-adjusting fluid could be supplied through the passageway  36 . 
         [0040]      FIG. 9  of the drawings shows a cyclonette  10 ′, similar to that of  FIG. 6 , but with the flow channels  24  and  26  replaced by flow channels  90  an  92 . The reduced diameter at point  94  results in an increase in velocity and a corresponding reduction in static pressure. The pressure within the chamber is directly related to the velocity head at this point. The outwardly tapering flow channel  92  results in a gradual decrease in fluid velocity, permitting efficient conversion of velocity head into static head as the fluid moves toward the discharge zone. 
         [0041]    As seen in  FIG. 10  of the drawings, a cyclonette  10 ′ is provided, but the vortex finder  12  of  FIGS. 6 and 9  of the drawings, is replaced by vortex finder  12 ′ in which the extension  34  protruding into the throat portion  22  is eliminated. As a result, the immediate transition from the downstream end of the modified vortex finder  12 ′ into the larger diameter throat portion  22  provides an additional shear zone for the generation of the desirable fine bubbles. 
         [0042]    In yet another modification of the hydraulic cavitation device of the present invention, as shown in  FIG. 7 , the cyclonette  10 ′ is combined with an insert  96  having a straight sided internal bore  98  and external threads  99 , which are complementary to internal threads  28 ′ in the modified cyclonette  10 ′. The insert  96  captures and holds in place within the cyclonette  10 ′ a washer-shaped orifice plate  100  having a central orifice  102 . This embodiment has shown to be most productive in the formation of multiple tiny bubbles, as the liquid being treated must first constrict from the larger diameter of the insert flow passage  98  to the restricted orifice  92  and then expand again into the throat  22  of the cyclonette  10 ′. In this embodiment, as in those of  FIGS. 9 and 10 , the passageway  36  may be used for the addition of a flow of the liquid being treated or a chemical or physical modifying substance in either a tangential, radial or substantially axial direction into the throat  22  of the cyclonette  10  or  10 ′. 
         [0043]    In some cases, it may be found desirable to eliminate the throat  22 , as shown in  FIG. 11  of the drawings, and convey the flow through the orifice  102  directly into an inwardly tapered flow channel  90 ′ and then outwardly into the radially outwardly tapering flow channel  92 . In this embodiment, as in the embodiments of  FIGS. 7 and 8 , the orifice plate  100  is held in place in the cyclonette  10 ′ by the insert  96 , which permits orifice plate  100  to be easily replaced for wear or the like. 
         [0044]    Turning now to  FIGS. 8 ,  8 A,  8 B and  8 C, it will be seen that a liquid  110  being delivered to the upstream end of a modified cyclonette  10 ′, via the outer manifold  58  and outer annular chamber  68 , passes through an insert  96  and thence through the orifice  102  of the orifice plate  100  and into the throat portion  22 . This creates an intense shear zone, resulting in a myriad of fine bubbles and droplets, some of which are dispersed at point  8 A in the flow channel  90  as depicted diagrammatically in  FIG. 8A . As the flow proceeds downstream through the ever-narrowing flow channel, the droplets move closer together and entrain pockets of vapor. Some of the kinetic energy of the liquid is utilized to accelerate and compress the pockets of vapor into bubbles until downstream flow channel  92  is reached. Beyond point  8 B, as the fluid moves to a zone of lower pressure, the bubbles tend to expand. Lastly, at point  8 C, the bubbles have assumed a size and configuration as shown in  FIG. 8C  of the drawings. 
         [0045]    Thus, it will be seen that the cavitation-generating technology of the present invention utilizes a vacuum chamber maintained within the individual cyclonettes by immersing their discharge ends in the liquid being treated and directing a high velocity jet of the liquid being treated to pass through a volume of vapor to increase bubble formation once vacuum is achieved. 
         [0046]    From the above, it will be apparent that the present invention provides an efficient method of harnessing the water molecule dissolution powers of hydraulic cavitation with the consequent release of aggressive hydroxyl radicals and highly effective liquid treatment. Additionally, the present invention utilizes conventional hydrocyclones and modifications thereof by operating them in a manner completely contrary to their intended purpose.