Abstract:
A fluid treatment apparatus comprises a fluid inlet  12  and outlet  13,  a granular filter media  15  arranged to filter fluid flowing from the inlet  12  to the outlet  13  and a device  14  arranged to vibrate or agitate the media as fluid flows through the media between the inlet  12  and outlet  13.  Vibrating or agitating the granulated media in this way produces a grinding effect which serves to kill any micro-organisms caught in the filter by rupturing their cell walls.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to fluid treatment and more particularly but not solely to the treatment of potable water to remove parasites and harmful protozoa, such as Cryptosporidium and Giardia.  
           [0002]    It is generally accepted that most raw water sources around the world contain harmful protozoa, such as Cryptosporidium and Giardia. These parasites are extremely resistant to conventional methods of disinfection and now constitute a severe health hazard to the public overall.  
           [0003]    It was thought that conventional sand filtration would provide an adequate barrier to guard against these parasites. This has been proved not to be the case, by the many outbreaks, recorded around the world in recent years.  
           [0004]    Technologies such as chlorine and biocides are ineffective against these micro-organisms. Ozone and micro-filtration have proved to be very expensive, with the latter producing a bio-hazardous waste. UV light has proved effective in some applications but its efficiency is badly affected by particulate in the water to be treated.  
         SUMMARY OF THE INVENTION  
         [0005]    An object of this invention is to provide a fluid treatment device which is highly efficient at killing parasites, such as Cryptosporidium and Giardia, which does not produce a bio-hazardous waste, and which is economic, energy efficient, substantially self-cleaning and unaffected by particulate in the water.  
           [0006]    In accordance with this invention there is provided a fluid treatment apparatus, comprising a fluid inlet and outlet, a granular filter media arranged to filter fluid flowing from the inlet to the outlet and means for vibrating or agitating the media as fluid flows through the media between the inlet and outlet.  
           [0007]    It has been found that when a granulated media is vibrated or agitated, and in particular with ultra sonic vibration it produces a multi-collision grinding effect on a micro scale, which is extremely efficient at killing micro-organisms. Thus, if a liquid containing parasites such as cryptosporidium or giardia passes through the vibrating media the parasites are killed due to the media colliding with the parasites, crushing them and rupturing of their cell walls. The process is highly efficient and repeatable.  
           [0008]    Also, in accordance with this invention, there is provided a method of treating fluid comprising passing the fluid through a granular filter media and vibrating or agitating the media while fluid continues to flow through the filter media.  
           [0009]    These and other objects, features and advantages of the present invention will be clearly understood through consideration of the following detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Embodiments of this invention will now be described by way of examples only and with reference to the accompanying drawings, in which:  
         [0011]    [0011]FIG. 1 is a sectional view through an embodiment of fluid treatment apparatus in accordance with this invention;  
         [0012]    [0012]FIG. 2 is a sectional view through a second embodiment of fluid treatment apparatus in accordance with this invention;  
         [0013]    [0013]FIG. 3 is a sectional view through a third embodiment of fluid treatment apparatus in accordance with this invention; and  
         [0014]    [0014]FIG. 4 is a sectional view through a fourth embodiment of fluid treatment apparatus in accordance with this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    Referring to FIG. 1 of the drawings, there is shown a fluid treatment apparatus comprising a watertight chamber  11  sealed at both ends and having an inlet port  12  and an outlet port  13 . The chamber can be split in two for maintenance via flanges  17  and water tight seal  19 . Positioned on and around the base of the chamber is a layer of granulated media  15 . Outside the chamber and attached to the base of the chamber, which is formed to act like a diaphragm, is a vibrator  14 .  
         [0016]    Preferably, the vibrator is an ultrasonic vibrator, which when activated vigorously vibrates the layer of granulated media. Placed in front of the outlet port is a mesh  16 , which retains the media inside the chamber.  
         [0017]    Referring to FIG. 1 of the drawings, assuming that the ultra sonic vibrator  14  is ‘on’ and the layer of granulated media  15  is vibrating. The liquid to be treated flows into the chamber via inlet port  12  through the vibrating media  15 , through the retaining mesh  16  and out of the chamber  11  via the outlet port  13 . Any parasites such as cryptosporidium and giardia are killed when passing through the vibrating media due to mechanical abrasion, collisions and the micro-grinding effect.  
         [0018]    The continuous vibration keeps the media clean and free from debris build up with particulate either being ground up and passed through the system or if hard granulated, adding to the media. The continuous vibration also keeps the pressure drop across the system at a minimum by maintaining the media loose packed.  
         [0019]    In drinking water chlorine does not affect the system therefor the chlorine residual can be maintained in the water ready to protect the mains.  
         [0020]    The system is modular in construction with several units able to be manifolded in parallel to increase the system throughput.  
         [0021]    In a second embodiment shown in FIG. 2, a cylindrical watertight chamber  11  sealed at both ends have an inlet port  12  and an outlet port  13 . The chamber can be split in two for maintenance via flanges  111  and water tight seal  112 . Passing through one end of the chamber  11  via seal  18  is a shaft  15 , which runs through the chamber, parallel to the walls of the chamber. Fixed to the shaft  15  is a plurality of perforated disks  16 , each disk having flexible seal  17 , attached to their periphery. Part or all of the space between each perforated disk is filled with a layer of granulated media  19  which is maintained in place by the disk  16 , flexible seal  17  and the wall of the chamber  11 . On the outside of the chamber, fixed to the shaft  15 , is a vibrator  110 .  
         [0022]    Preferably the vibrator is an ultrasonic vibrator, which when activated vigorously vibrates the layers of granulated media between the disks  16  via shaft  15 .  
         [0023]    The invention will now be described in detail with the aid of FIG. 2. Assuming that the ultra sonic vibrator  14  is ‘on’; the shaft  15  vibrates causing the layers of granulated media  19  to vibrate. The liquid to be treated flows into the chamber via inlet port  12 , through each of the perforated disks of vibrating media  16 , and out of the chamber  11  via the outlet port  13 . The flexible seals  17  make a watertight seal to the wall of the chamber so the liquid cannot bypass the media  19 .  
         [0024]    Any parasites, such as Cryptosporidium and Giardia are killed when passing through the disks of vibrating media due to mechanical abrasion, collisions and the micro grinding effect previously described in embodiment 1.  
         [0025]    In a third embodiment shown in FIG. 3, a cylindrical watertight chamber  11  sealed at both ends has an inlet port  12  and an outlet port  13 . The chamber can be split in two for maintenance via flanges  19  and water tight seal  110 . The chamber is supported at both ends by rubber mounts  17 , which allows the cylindrical chamber some movement. Partially filling the chamber is a column of granulated media  15 , on top of which is placed a layer of large particle size media  18 . Outside the chamber and attached to the wall of the chamber is a vibrator  14 .  
         [0026]    Preferably the vibrator is an ultrasonic vibrator, which when activated vigorously vibrates the column of granulated media in the direction across the diameter of the chamber. Placed in front of the outlet and inlet ports are meshes  16  &amp;  111 , which together with the large size media  18  retains the granulated media inside the chamber.  
         [0027]    The invention will now be described in detail with the aid of FIG. 3. Assuming that the ultra sonic vibrator  14  is ‘on’ and the column of granulated media  15  is vibrating. The liquid to be treated flows into the chamber via inlet port  12 , through mesh  111 , through the column of vibrating media  15 , through the retaining mesh  16  and out of the chamber  11  via the outlet port  13 . Any parasites, such as Cryptosporidium and Giardia, are killed when passing through the vibrating media due to mechanical abrasion, collisions and the micro grinding effect previously described in embodiment 1.  
         [0028]    In some circumstances it is desirable to have a disposable cartridge type system. For instance, a system suitable for domestic applications would need this facility.  
         [0029]    In a fourth embodiment shown in FIG. 4, a cylindrical watertight disposable cartridge  11  has an inlet port  12  and an outlet port  13 . The cartridge  11  fixes onto the ‘L’ shaped mounting plate  16  via mounting  114  and the spring-loaded connector  19  and support block  115 . The plate  16  is resiliently mounted in a stationary position via resilient mounts  113 . The cartridge is sealed to the inlet and outlet ports  12  &amp;  13  in a watertight manner by ‘O’ ring seals  17  &amp;  110 . Partially filling the cartridge and supported by mesh  111  &amp;  112 , is a column of granulated media  15 . Attached to the “L” shaped plate  16  is a vibrator  14 .  
         [0030]    Preferably the vibrator is an ultrasonic vibrator, which when activated vigorously vibrates the plate and hence the column of granulated media, in the direction across the diameter of the cartridge. The outlet port mesh  111  retains the granulated media inside the cartridge.  
         [0031]    This embodiment will now be described in detail with the aid of FIG. 4. Assuming that the ultrasonic vibrator  14  is ‘on’ and the cartridge  11  of granulated media  15  is vibrating via the vibrating ‘L’ shaped plate  16 . The liquid to be treated flows into the cartridge  11  via inlet port  12 , through the retaining mesh  111 , through the column of vibrating media  15 , through the retaining mesh  112  and out of the chamber  11  via the outlet port  13 .  
         [0032]    Any parasites, such as Cryptosporidium and Giardia are killed when passing through the vibrating media due to mechanical abrasion, collisions and the micro-grinding effect previously described in the first embodiment.  
         [0033]    In alternative embodiments, the vibratory devices  14 , 110  may be replaced by agitators.  
         [0034]    While the preferred embodiment of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims.