Abstract:
There is disclosed a fluid treatment device comprising a housing for receiving a flow of fluid. The housing comprises a fluid inlet, a fluid outlet, a closed fluid treatment zone disposed between the fluid inlet and the fluid outlet. Disposed in the housing is at least one elongate radiation source assembly having a longitudinal axis disposed in the fluid treatment zone substantially parallel to a direction of the flow of fluid through the housing. The radiation source assembly comprises an elongate radiation source disposed in a protective sleeve to define a substantially annular passageway. The protective sleeve has opposed open ends configured to permit heat to exit the passageway and the housing through at least one of the opposed open ends of the sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application claims the benefit under 35 U.S.C. § 19(e) of provisional patent application Ser. No. 60/786,358, filed Mar. 28, 2006, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a fluid treatment device. More particularly, in its preferred embodiment, the present invention relates to an ultraviolet radiation water treatment device.  
         [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 5,590,390 (all assigned to the assignee of the present invention) all describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation to inactivate microorganisms present in the fluid.  
         [0006]     The devices and systems described in the &#39;809, &#39;980 and &#39;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. Since, at higher flow rates, accurate fluid level control is difficult to achieve in gravity fed systems, fluctuations in fluid level are inevitable. Such fluctuations could lead to non-uniform irradiation in the treated fluid.  
         [0007]     So-called 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 &#39;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. A disadvantage with this kind of closed fluid treatment device is that the seal between the radiation source module and the housing must be broken each time the former is to be serviced. This confers additional cost and complexity to the servicing needs of the device.  
         [0008]     U.S. Pat. No. 6,500,346 (assigned to the assignee of the present invention) teaches a fluid treatment device, particularly useful for ultraviolet radiation treatment of fluids such as water. The device comprises a housing for receiving a flow of fluid. The housing has 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 having a longitudinal axis disposed in the fluid treatment zone substantially transverse to a direction of the flow of fluid through the housing. The fluid inlet, the fluid outlet and the fluid treatment zone are arranged substantially collinearly with respect to one another. The fluid inlet has a first opening having: (i) a cross-sectional area less than a cross-sectional area of the fluid treatment zone, and (ii) a largest diameter substantially parallel to the longitudinal axis of the at least one radiation source assembly.  
         [0009]     Many of the above mentioned fluid treatment systems have achieved significant commercial success in the treatment of municipal waste water and/or municipal drinking water.  
         [0010]     In certain cases, it would be desirable to have a fluid treatment system for use in treating relatively low volumes of water—e.g., for domestic use, for use in an office environment, etc.  
         [0011]     In this regard, reference may be made to: 
        U.S. Pat. No. 4,179,616,     U.S. Pat. No. 5,471,063 (assigned to the assignee of the present invention),     U.S. Pat. NO. 6,139,726,     U.S. Pat. No. 6,679,068, and     U.S. Pat. No. 6,832,844.        
 
         [0017]     The &#39;063 patent teaches fluid disinfection unit comprising a fluid treatment housing, an electrical supply module and electrical connection means connecting the fluid treatment housing and the electrical supply module. The fluid treatment housing comprises a fluid inlet and a fluid outlet in communication with a reaction chamber, an ultraviolet radiation lamp disposed in the reaction chamber and having a first electrical connector at a first end thereof and a second end thereof being closed. The second end of the ultraviolet radiation lamp is received and held in place by tapered, helical spring. The electrical supply module comprises ballast and which may be removably connected to the ultraviolet radiation lamp and the electrical supply module.  
         [0018]     The device taught by the &#39;063 patent has been commercially available from Trojan Technologies Inc. under the tradename Trojan UVMax™ and has achieved commercially success. Notwithstanding this, there is room for improvement.  
         [0019]     One of the problems with devices such as those taught by the &#39;063 patent is fluctuation in the environment surrounding the radiation source. This occurs primarily due to the fact that the temperature of the fluid (typically water) surrounding lamp is variable. The variability in temperature can occur to variability of the temperature of the fluid entering the fluid treatment system. Further, the variability of the temperature can occur due to fluid resting in the system when the system is in a non-flowing condition. Since the radiation source is constantly powered, fluid resting in the system will become relatively warmer (i.e., as compared to when fluid is passing through the system) thereby increasing the temperature of the environment around the radiation source.  
         [0020]     In recent years, improvements in radiation source (e.g., lamp) technology have developed to the point that radiation sources are designed to operate at an optimum temperature—e.g., for achieving specified disinfection levels and the like. It is important to optimally control the temperature surrounding the radiation source to maintain optimium operation of the radiation source.  
         [0021]     Further, over the years, the art has transitioned toward the use of protective sleeves for radiation lamps, wherein the protective sleeves an open end and a closed end thereby facilitating sealing of the radiation lamp—this is particularly important in water submersible systems.  
         [0022]     Accordingly, it would be highly desirable to have a fluid treatment system in which the temperature of the environment surrounding the radiation source is relatively constant. More particularly, it would be highly desirable to have a fluid treatment system in which the occurrence of resting fluid described above and fluid temperature fluctuations had little or no effect on the operating temperature of the radiation source.  
       SUMMARY OF THE INVENTION  
       [0023]     It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.  
         [0024]     It is another object of the present invention to provide a novel fluid treatment system.  
         [0025]     Accordingly, in one of its aspects, the present invention provides a fluid treatment device comprising a housing for receiving a flow of fluid, the housing comprising a fluid inlet, a fluid outlet, a closed fluid treatment zone disposed between the fluid inlet and the fluid outlet, and at least one elongate radiation source assembly having a longitudinal axis disposed in the fluid treatment zone substantially parallel to a direction of the flow of fluid through the housing; 
        wherein the radiation source assembly comprises an elongate radiation source disposed in a protective sleeve to define a substantially annular passageway, the protective sleeve having opposed open ends configured to permit heat to exit the passageway and the housing through at least one of the opposed open ends of the sleeve.        
 
         [0027]     Thus, the present inventors have discovered a fluid treatment system in which performance of the radiation source and temperature of the fluid being treated are not dependent on one another. This is achieved by having a gap, preferably an annular gap between the radiation source and a protective sleeve that is open at both ends. The open nature of the protective sleeve allows for heat build-up in the gap to be dissipated or otherwise vent thereby allowing the radiation source to operate in an optimal manner. Put another way, the gap between the radiation source and the protective sleeve serves as an insulative barrier between the radiation source and the fluid being treated thereby decoupling performance of the radiation source and the temperature of the fluid being treated.  
         [0028]     Dissipation of the heat build up from the gap can occur by natural forces of convection and/or by use of auxiliary means such as a fan and the like facilitate dissipation of the heat build up. Preferably, the radiation source comprises an electrical connection at a proximal portion thereof and the combination of the radiation source and protective sleeve are configured so that dissipation of at least a portion of the heat build up from the annular gap occurs in a direction toward the distal portion of the radiation source (i.e., opposite to the end of the radiation source that comprises the electrical connection). Such distal portion cooling of the radiation source is particular advantageous if a metal-amalgam (preferably mercury-amalgam) composition is disposed in the distal portion of the radiation source.  
         [0029]     Preferably, the fluid treatment system is in the form of a water treatment system. Preferably, the radiation source in is an ultraviolet radiation lamp, more preferably a metal-amalgam containing ultraviolet radiation lamp. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]     Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:  
         [0031]      FIG. 1  illustrates a perspective view of a preferred embodiment of the present fluid treatment system;  
         [0032]      FIG. 2  illustrates an enlarged sectional view of an upper portion of fluid treatment system illustrated in  FIG. 1 ;  
         [0033]      FIG. 3  illustrates an enlarged section view of a lower portion of fluid treatment system illustrated in  FIG. 1 ;  
         [0034]      FIG. 4  illustrates the upper portion of fluid treatment system shown in  FIG. 1  with the parts disassembled for clarity;  
         [0035]      FIGS. 5-9  illustrate the keyed fit between the radiation source and the sleeve bolt in the fluid treatment system illustrated in  FIGS. 1-4 ;  
         [0036]      FIG. 10  illustrates an enlarged perspective view of an end of a conventional metal-amalgam (e.g., mercury-amalgam) radiation lamp;  
         [0037]      FIG. 11  illustrates an enlarged perspective view of a proximal end of the radiation lamp used in the fluid treatment system illustrated in  FIGS. 1-4 ;  
         [0038]      FIGS. 12-18  illustrate an enlarged perspective views of the distal end of the radiation lamp used in the fluid treatment system illustrated in  FIGS. 1-4 ;  
         [0039]      FIGS. 19-23  each illustrate an enlarged perspective view of a preferred locator element that may be used in the distal portion of the radiation lamp used in the fluid treatment system illustrated in  FIGS. 1-4 ;  
         [0040]      FIG. 24  illustrates a perspective view of a first embodiment of an arrangement for varying the size of the window of the locator element used at the distal portion of the radiation lamp;  
         [0041]      FIGS. 25-28  illustrate various views of a second embodiment of an arrangement for varying the size of the window of the locator element used at the distal portion of the radiation lamp; and  
         [0042]      FIGS. 29-31  illustrate various embodiments of alternative arrangements to vary the size of the window positioned adjacent to the metal-amalgam (e.g., mercury amalgam) composition in the radiation lamp used in the fluid treatment system illustrated in  FIGS. 1-4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]     With reference to  FIG. 1 , there is illustrated a fluid treatment system  100  comprising a pair of threaded ports  105 ,  110 . One of ports  105 ,  110  acts as fluid inlet while the other acts as a fluid outlet.  
         [0044]     Ports  105 ,  110  are connected to a fluid treatment chamber  115 . Fluid treatment chamber  115  may be constructed from stainless steel or any other suitable material. Disposed in fluid treatment chamber  115  is a threaded port  120  for receiving an optical radiation sensor (not shown).  
         [0045]     With reference to  FIGS. 1-2 , disposed within chamber  115  is a radiation source assembly  125 . Radiation source assembly  125  comprises a radiation lamp  130  disposed within a radiation transparent, protective sleeve  135 . Protective sleeve  135  is open at both ends. A sleeve bolt  140  is used to secure radiation source assembly  125  in housing  115  and to position radiation source assembly  125  for connection to an electrical connection harness  145 .  
         [0046]     As illustrated, the wire conduit emanating from electrical connection harness points away from threaded port  120 . This avoids a situation where such wire conduit might interfere with servicing and/or replacement of the optical radiation sensor.  
         [0047]     With further reference to  FIG. 2 , a proximal portion of radiation source assembly  125  comprises a first locator element  150  that is secured to radiation source  130 . The manner by which first locator element  150  is secured to radiation lamp  130  is not particularly restricted. This can be achieved by gluing or by mechanical means within the purview of a person skilled in the art.  
         [0048]     First locator element  150  comprises a trio of positioning elements  151 ,  152 ,  153 . As can be seen, for example, in  FIGS. 4-9 , positioning elements  151  and  152  have a similar wedge-shaped cross-section whereas positioning element  153  has a substantially rectangular-shaped cross-section. Also disposed on locator element  150  is a pair of apertures  154 ,  155  which receive electrical pin connectors (not shown) from radiation lamp  130 . Disposed between apertures  154 ,  155  is a barrier element  156  which serves as a dielectric barrier to obviate or mitigate electrical arcing between the connectors that emanate from apertures  154 ,  155 .  
         [0049]     As further illustrated, sleeve bolt  140  comprises a trio of notches  141 ,  142 ,  143  which are designed to receive positioning elements  151 ,  152 ,  153 , respectively of sleeve bolt  140 . Thus, it will be understood that, given the unique shape of positioning element  153  (compared to positioning elements  151 ,  152 ), locator element  150  can only be secured to sleeve bolt  140  in a unique manner. Put another way, locator element  150  is keyed with respect to sleeve bolt  140 .  
         [0050]     As further illustrated, sleeve bolt  140  comprises a pair of grooved portions  144  which serve to secure sleeve bolt  140  to housing  115 .  
         [0051]     When sleeve bolt  140  is secured to housing  115 , an O-ring  146  is compressed to provide a substantially fluid tight seal between sleeve bolt  140 , housing  115  and protective sleeve  135 —see, for example,  FIG. 2 .  
         [0052]     Once it is desired to install radiation lamp  130  in sleeve bolt  140 , positioning elements  151 ,  152 ,  153  are aligned with notches  141 ,  142 ,  143 , respectively—see  FIGS. 6 and 7 . Next, radiation lamp  130  is rotated in a clockwise direction so that barrier element  156  is substantially aligned with an aperture  157  for receiving a grounding pin from electrical connection harness  145 —see  FIGS. 8 and 9 .  
         [0053]     At this point, radiation lamp  130  is properly positioned for connection to electrical connection harness  145  having a ground pin  144  as shown in  FIGS. 1 and 4 . This connection may be achieved in a conventional manner. One of the advantages of this approach is that the ground pin is connected to aperature  157  prior to electrical connection between electrical connection harness  145  and radiation lamp  130 .  
         [0054]     With reference to  FIG. 3 , the lower portion of fluid treatment system  100  is illustrated. As shown, the distal portion of radiation lamp  130  has secured thereto a second locator element  160  which comprises a trio of positioning elements  161 ,  162 ,  163 . Again, second positioning element  160  may be secured to radiation lamp  130  in a conventional manner.  
         [0055]     A distal end of lamp  130  is shown in  FIG. 10 . As illustrated, the end of lamp  130  comprises a pinch portion  131  having an electrical pin  132  emanating there from. An electrical connector  133  is secured to pin  132  and is returned to the proximal region of lamp  134  connection to a pin (not shown) which emanate from one of apertures  154 ,  155  emanating from first locator element  150 .  
         [0056]     In the embodiment illustrated in  FIG. 12 , second positioning element  160  is effectively functioning as a cap to receive pinch portion  131  (not shown) of the distal end of lamp  130 .  
         [0057]     With further reference to  FIG. 3 , a distal portion of radiation lamp  130  comprises a reservoir  165  for receiving a metal-amalgam (preferably mercury-amalgam) composition. As is known in the art, optimum operation of lamp  130  is achieved by controlling operating temperature of the lamp, particularly the temperature of the metal-amalgam composition contained in reservoir  165 . Of course, those of skill in the art will recognize that reservoir  165  may be replaced with a so-called metal-amalgam spot disposed in an end region of radiation lamp  130  below the filament.  
         [0058]     As further illustrated in the combination of  FIGS. 2 and 3 , the positioning elements on locator elements  150  and  160  act in combination to align radiation lamp  130  concentrically within protective sleeve  135 . Further, since protective sleeve  135  is open at both ends, any heat build-up in the space between radiation lamp  130  and protective sleeve  135  will be removed by the forces of convection typically in the direction of arrow A ( FIG. 2 ) and/or, in some case, in the direction of arrow B ( FIG. 3 ). The provision of an open passage from the annular gap between radiation lamp  130  and protective sleeve  135  facilitates dissipation of heat build up in this space which would otherwise have a deleterious effect on operation of the lamp by virtue of the fact that the metal-amalgam composition in reservoir  165  would be subjected to the influence of the variable heat.  
         [0059]     The dissipation of heat may be facilitated further by the provision of a cooling system  200  as shown in  FIG. 4 . Cooling system  200  comprises a cooling block  205  having a series of cooling fins  210 . A fan  215  is positioned adjaced to cooling block  205  and serves to draw heat away from cooling block  205  through a series of openings  218  in a cover  220 .  
         [0060]     With reference to  FIGS. 13-18 , there are illustrated various alternate embodiments of second locater element  160 , namely locator elements  160   a - 160   f , respectively.  
         [0061]     Thus,  FIG. 13  illustrates second protector element  160   a  in which the end portion thereof is open to facilitate dissipation of heat build-up around pinch portion  131  of radiation lamp  130 .  
         [0062]     In  FIG. 14 , second locater element  160   b  has a portion of the body in thereof cut away to further improve heat dissipation from pinch portion  131  and from the area of radiation lamp  130  in which is disposed the metal-amalgam composition referred to above.  
         [0063]     In  FIG. 15 , second locater element  160   c  is closed at the end thereof but has a portion of the body thereof cut away to facilitate heat dissipation. As will be further seen, the positioning elements  161 ,  162  on locater element  160   c  are disposed proximally of the distal end of second locater element  160   c.    
         [0064]     In  FIG. 16 , second locater element  160   d  is similar to second locater element  160   c  illustrated in  FIG. 15  with the exception that the end thereof is open as shown in  FIG. 13 .  
         [0065]     In  FIG. 17 , second locater element  160   e  is in the form of a ring which is placed proximally of pinch portion  131  of radiation lamp  130 .  
         [0066]     In  FIG. 18 , second locater element  160   f  comprises a basket portion  164  which serves to protect pinch portion  131  of radiation lamp  130 .  
         [0067]     In  FIGS. 19-22 , there are illustrated enlarged perspective views of various embodiments of the second locater element illustrated in  FIGS. 13-18 .  
         [0068]     In  FIG. 23 , there is illustrated an enlarged perspective view of a further alternate embodiment of the second locater element, namely, second locater element  160   g  which comprises a series of apertures  166  to facilitate dissipation of heat in the area of the radiation lamp (not shown) in which is disposed the metal-amalgam composition described above.  
         [0069]     With reference to  FIG. 24 , there is shown yet a further alternate embodiment of the second locater element, namely, second locater element  160   h . For clarity, the positioning elements are not shown in  FIG. 24 . Second positioning element  106   h  comprises an inner cylindrical element  170  and an outer cylindrical element  171  that are interconnected via a spring element  172 . Inner cylindrical element  170  comprises a trio of rectangular shaped windows  173 . Outer cylindrical element  171  comprises a trio of rectangular windows  174 .  
         [0070]     As will be appreciated by those of skill in the art, when windows  173  and  174  are substantially aligned, the so-called venting capacity of second positioning element  160   h  is maximized. At the other extreme, where there is no overlap between windows  173  and  174 , the so-called venting capacity of second positioning element  160   h  is minimized. Between these two extremes, there are a infinite number of intermediate positions in which there is partial overlap between windows  173  and  174  allowing for tuning or variability in the venting capacity of second positioning element  160   h . Such tuning can be achieved by the selection of spring element  172 . In some cases, spring element  172  can be made from a heat sensitive material (e.g., nitonal) such that spring element  172  will bias in a manner that increases or decreases the venting capacity of second locating element  160   h  depending on the temperature of the environment surrounding spring element  172 .  
         [0071]     With reference to  FIGS. 25-28 , there is shown a further alternate embodiment of the second locater element, namely, second locater element  160   i . Again, the positioning elements are not shown for clarity. For ease of understanding, an asterisk (*) has been used as a suffix to denote elements in FIGS.  25  which correspond substantively to those appearing in  FIG. 24 .  
         [0072]     The principal difference in  FIG. 25  is the use of a cogwheel  175  in  FIG. 25  (in place of spring element  172  in  FIG. 24 ) in combination with a lock element  176  to achieve relative movement between cylindrical element  170 * and cylindrical element  171 *.  
         [0073]     Further, a series of indicia  177  is provided on the cylindrical element  170 * and a single marker  178  is provided on cylindrical element  171 *. The adjustment of the venting capacity of second positioning element  160   i  is achieved by positioning the appropriate indicium  177  in alignment with marker  178 . This can be done, for example, knowing the length of the radiation lamp, the position of the metal-containing amalgam composition with respect to windows  173 * and  174 *, the diameter of protective sleeve  135 , the ambient air temperature, the type of radiation lamp  130  and other factors. The venting capacity of second locater element  160   i  can be adjusted during assembly of the fluid treatment system, replacement of the radiation lamp, etc.  
         [0074]     With reference to  FIGS. 29-31 , there are illustrated various alternate embodiments to cylindrical element  170 ,  171 ,  170 * and  171 * referred to above. The principal change is to the shape of the windows in the cylindrical elements.  
         [0075]     In  FIG. 29 , the V-shaped window of each cylindrical element provides for non-linear tuning of the venting capacity of the second locater element. By this it is meant that the degree of the overlap between the windows of the cylindrical elements various non-linearly with relative movement of the cylindrical elements.  FIG. 31  illustrates circular windows in which a similar non-linear relationship can be seen.  
         [0076]     In  FIG. 30 , the relationship is linear as was the case with the embodiments discussed above with reference to  FIGS. 24-28 .  
         [0077]     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. For example, it is possible to modify the illustrated embodiments to utilize a fan or the like (with or without cooling system  200 ) to assist the natural convection of heat build-up in the gap between radiation lamp  130  and protective sleeve  135 . Further, it is possible to substitute metal-amalgam with metal only (e.g., pure mercury). Still further, in certain cases, it is possible to omit second locator element  160  from radiation source assembly  125 . It is therefore contemplated that the appended claims will cover any such modifications or embodiments.  
         [0078]     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.