Abstract:
There is described a fluid treatment system comprising an array of independent fluid treatment reactors. The reactors are arranged in a manner whereby a flow of fluid may be passed through the array in a substantially helical direction. The fluid treatment system is capable of treating large volumes of fluid (e.g., water) while requiring a relatively small foot print. In essence, the present fluid treatment system concentrates a relatively large number of radiation sources in a relatively small amount of space resulting in the ability to treat large volumes of fluid (e.g., water).

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present application claims the benefit under 35 U.S.C. §119(e) of provisional patent application S. No. 60/323,383, filed Sep. 20, 2001, the contents of which are hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    In one of its aspects, the present invention relates to a fluid treatment system. In another of its aspects, the present invention relates to a method of treating fluid.  
           [0004]    2 Description of the Prior Art  
           [0005]    Fluid treatment devices and systems are known. For example, U.S. Pat. Nos. 4,482,809, 4,872,980, 5,006,244 and Re. Pat. No. 36,896 (all assigned to the assignee of the present invention) all describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation to inactive microorganisms present in the fluid.  
           [0006]    The devices and systems described in the 809, 980 and 244 patents generally include several UV lamps each of which are mounted within sleeves extending between two support arms of the frames. The frames are immersed into the fluid to be treated which is then irradiated as required. The amount of radiation to which the fluid is exposed is determined by the proximity of the fluid to the lamps. One or more UV sensors may be employed to monitor the UV output of the lamps and the fluid level is typically controlled, to some extent, downstream of the treatment device by means of level gates or the like.  
           [0007]    The system described in the 896 patent is a significant advance in the art in that it obviates a number of disadvantages deriving from the devices and systems 809, 980 and 244 patents. Unfortunately, the system described in the 896 patent is ideally suited for use in an open, channel-like system and is not readily adaptable to be used in a completely closed system where the flow of fluid is fed under pressure in a pipe.  
           [0008]    Closed fluid treatment devices are known—see, for example, U.S. Pat. No. 5,504,335 (assigned to the assignee of the present invention). The 335 patent teaches a closed fluid treatment device comprising a housing for receiving a flow of fluid. The housing comprises a fluid inlet, a fluid outlet, a fluid treatment zone disposed between the fluid inlet and the fluid outlet, and at least one radiation source module disposed in the fluid treatment zone. The fluid inlet, the fluid outlet and the fluid treatment zone are in a collinear relationship with respect to one another. The at least one radiation source module comprises a radiation source sealably connected to a leg which is sealably mounted to the housing. The radiation source is disposed substantially parallel to the flow of fluid. The radiation source module is removable through an aperture provided in the housing intermediate to fluid inlet and the fluid outlet thereby obviating the need to physically remove the device for service of the radiation source.  
           [0009]    While the closed fluid treatment device taught in the 335 patent (including the prior art device referred to in that patent) has been commercially successful to some degree, there is still room for improvement in the art.  
           [0010]    Specifically, in many installations where it is desirable to treat large amounts of fluid (e.g., water), there is insufficient room to utilize a device such as that described in the 809, 980, 244 and 896 patents. Further, devices such as those taught in the 335 patent are constrained by the volume of fluid (e.g., water) which they can adequately treat (e.g., to subject the fluid to a radiation dose sufficient to perform the desired treatment).  
           [0011]    Accordingly, there remains a need in the art for a fluid treatment system which combines the capacity of fluid volume treatment of the 809, 980, 244 and 896 patents while requiring a space of “foot print” not much larger than that used in the device taught by the 335 patent.  
         SUMMARY OF THE INVENTION  
         [0012]    It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.  
           [0013]    Accordingly, in one of its aspects, the present invention provides a fluid treatment system comprising an array of independent fluid treatment reactors arranged in a manner whereby a flow of fluid may be passed through the array in a substantially helical direction.  
           [0014]    In another of its aspects, the present invention provides a method of treating fluid comprising the steps of feeding fluid to be treated through an array of independent fluid treatment reactors arranged in a substantially helical direction.  
           [0015]    Thus, the present inventors have developed a fluid treatment system which is capable of treating large volumes of fluid (e.g., water) while requiring a relatively small foot print. In essence, the present fluid treatment system concentrates a relatively large number of radiation sources in a relatively small amount of space resulting in the ability to treat large volumes of fluid (e.g., water).  
           [0016]    While the present invention relates to fluid treatment devices generally, the most preferred application of the system is in treating liquids such as water (e.g., municipal waste water, drinking water, contaminated ground water, industrial waste water and the like). However, those with skill in the art will recognize that the present fluid treatment system will also find utility in treating other types of fluids such as gases and the like.  
           [0017]    The currently preferred embodiment of the present fluid treatment system comprises helical arrangement of interconnected fluid treatment subsystems or “reactors”. While the number of reactors is not specifically restricted, in a preferred embodiment, there are nine reactors arranged in rows of the three reactors with three such rows in a stacked arrangement. With this preferred arrangement, is it possible to implement an overall treatment system which comprises, for example from about 250 to about 650 amalgam radiation lamps in a footprint of about 250 square feet, inclusive of all hardware (including virtually all hardware for the system such as reactors, ballasts and the like). The number of reactors in each row of the helical pattern is not particularly restricted. Preferably, each row in the helical pattern comprises at least  3  reactors, preferably from 3 to 6 reactors, per row of the helical pattern. Further the number of rows of reactors in the helical pattern is not particularly restricted. Preferably, the helical pattern comprises at least 2, preferably from 2 to 10, rows of interconnected reactors. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:  
         [0019]    [0019]FIG. 1 illustrates a perspective view of a preferred embodiment of the present fluid treatments system;  
         [0020]    [0020]FIG. 2 illustrates a top view of the system illustrated in FIG. 1;  
         [0021]    [0021]FIG. 3 illustrates a first side elevation of the system illustrated in FIG. 1;  
         [0022]    [0022]FIG. 4 illustrates a second side elevation of the system illustrated in FIG. 1; and  
         [0023]    [0023]FIG. 5 illustrates a section of one reactor used in the system illustrated in FIGS.  1 - 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    Thus, with reference to FIGS.  1 - 4 , there is illustrated a fluid treatment system  100 . Fluid treatment system  100  comprises a fluid treatment system reactor array  105  and a master control panel  110  which is remote from fluid treatment reactor array  105 .  
         [0025]    Fluid treatment reactor array  105  comprises an inlet  115  and an outlet  120 . Fluid treatment reactor array  105  further comprises a skid  125 . Fluid treatment reactor array  105  further comprises a trio of power control panels  130 , 135 , 140 .  
         [0026]    Skid  125  comprises a grid-like series of vertical supports  145  which are interconnected to a series of horizontal supports  150 .  
         [0027]    The network of vertical supports  145  and horizontal supports  150  provides a support system for nine radiation reactors  155 . The design of each reactor  155  is the same and will be described in more detail below.  
         [0028]    As shown in FIGS.  1 - 4 , the radiation reactors are stacked in rows of three on top of one another. This arrangement is facilitated through the use of elbows  160  as needed.  
         [0029]    With reference to FIG. 5, radiation reactor  155  comprises a reactor inlet  165  and a reactor outlet  170 . Reactor inlet  165  and reactor outlet  170  are interconnected by a substantially tubular housing  175 . Tubular housing  175  has disposed therein a series of elongate tubes  180 . Tubes  180  are made from a radiation transparent material such as, for example, quartz.  
         [0030]    As illustrated, one end of each tube  180  is closed while the other end is sealingly engaged to a plate  185 . The manner of achieving engagements between tubes  180  and plate  185  is conventional and within the purview of a person skilled in the art. Disposed within each tube  180  is a radiation source (not shown for clarity). Preferably, the radiation source is an ultraviolet radiation source. The nature of the ultraviolet radiation source is not particularly restricted. In one embodiment, the ultraviolet radiation source may be low-pressure ultraviolet radiation lamp. In another embodiment, the ultraviolet radiation source may be a medium pressure lamp. In yet another embodiment, the ultraviolet radiation source may be a low-pressure amalgam lamp. In yet another embodiment, the ultraviolet radiation source may be a low-pressure, high-output (LPHO) lamp. Such lamps are commercially available and are known in the art. As is known in the art, the radiation source typically comprises electrical leads (again not shown for clarity) which, in this case, would emanate from the open end of tubes  180  to a supplementary housing  190  defined by an end cap  195  attached to a flange  200  of tubular housing  175 .  
         [0031]    Disposed within tubular housing  175  is a support plate  205  which serves to support each elongate tube  180  near the closed end thereof.  
         [0032]    Also disposed within tubular housing  175  are a pair of cleaning yokes  210 . Cleaning yokes  210  are attached to a screw drive  215 . Screw drive  215  is attached to a drive motor  220  which is disposed in supplementary housing  190 . Preferably, cleaning yokes  210  comprise mechanical scrapers. For example, it is possible for cleaning yokes  210  to comprise a cleaning ring per elongate sleeve. Preferably, the cleaning ring comprises an O-ring which surrounds elongate tubes  180 . The O-ring would scrape fouling materials from the exterior of elongate tubes  180  as cleaning yokes  210  are moved along the tubes by screw drive  215 . Of course, other cleaning systems may be attached to screw drive  215  such as chemical-mechanical cleaning systems (e.g., similar in design and operation to that described in the 896 patent referred to above).  
         [0033]    The number of elongate tubes  180  disposed within tubular housing  190  is not particularly restricted. For example, the number of tubes (and thus the number of radiation sources or lamps) disposed within each reactor  155  may be from 3 to 72.  
         [0034]    The operation of fluid treatment system  100  will now be described.  
         [0035]    Water which is in need of disinfection enters fluid treatment system  100  at inlet  115 . Inlet  115  is connected to reactor inlet  165  of one reactor  155 . Water then enters that specific reactor  155  and is treated by radiation emanating from elongate tubes  180 . The treated water then exits that reactor  155  via the outlet  170  and enters the next reactor  155 . This sequence of events repeats itself until the fluid had been passed through all nine reactors after which it exits fluid treatment system  100  via outlet  120 . As will be appreciated by those of skill in the art, in the illustrated embodiment, the fluid travels in a generally helical fashion through fluid treatment reactor array  105 . As will be further appreciated by those of skill in the art, reactor  155  is simply a repeating unit which can be used in fluid treatment reactor array  105  with minimal additional pieces (e.g., elbows  160  and straight sections which interconnect the system inlet/outlet to the nearest reactor  155 .  
         [0036]    A distinct advantage of the present fluid treatment system is that a large volume of fluid can be treated since the fluid is passing through a series of 9 reactors. Further advantage of course is that this can be achieved using a very small footprint for the fluid treatment reactor array.  
         [0037]    It will be apparent to those of skill in the art that variations to the specific design shown in FIGS.  1 - 5  can be made without departing from the spirit and scope of the present invention. For example, it is possible to modify, replace or supplement elbows  160  with one or more T-shaped sections, each T-shaped section comprising suitable valving or the like, which allow for diversion (e.g., by means of supplementary piping, hoses or the like) of fluid flow from a portion of fluid treatment reactor array  105  while leaving the remaining portion of array  105  operational. This can be advantageous to do maintenance on a portion of the array without having to shut down the entire system or to conserve energy if the transmittance of the water being treated increases. Further, it is possible to modify the illustrated embodiment to increase the number of rows of reactors in the fluid treatment reactor array and/or to increase the number of reactors in each row in the array. Still further, while the illustrated embodiment shows a control panel (typically containing a programmable logic controller) remote from fluid treatment reactor array  105 , it is, of course, possible to modify the illustrated embodiment to incorporate the function of control panel  110  in one or more of power control panels  130 , 135 , 140 .  
         [0038]    The diameter of tubular housing  175  is not particularly restricted. Preferred diameters are within the range from about 6 inches to about 40 inches (particularly preferred diameters are 8 inches, 12 inches, 16 inches, 20 inches, 24 inches, 30 inches and 40 inches).  
         [0039]    In the illustrated embodiment, the inlet to each reactor  155  is oriented such that the direction of fluid flow is substantially parallel to elongate tubes  180  whereas the orientation of reactor outlet  170  is such that the flow of fluid there through is substantially transverse perpendicular to the longitudinal axis of elongate tubes  180 . While this is a highly preferred orientation of reactor inlet  165  and reactor outlet  170  in relation to the direction of fluid flow and longitudinal axis of elongate tubes  180 , it is possible to modify these specific features of reactor  155 .  
         [0040]    A further distinct advantage of the present fluid treatment system is that the rows of reactors used in fluid treatment reactor array can be modularized. This facilitates shipping and construction of the system and also facilitates expansion or reduction of system capacity in the future. For example, with respect to the illustrated embodiment, it will be seen that vertical supports  145  comprise flange plate elements surrounding each row of reactors  155 . This allows for modulization of rows of reactors  155  and the advantages associated therewith.  
         [0041]    While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.  
         [0042]    All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each, individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.