Abstract:
A filter system includes a distribution valve operable to direct a received fluid stream to first and second outlets during respective first and second cycles. A filtering system filters at least some fluid output from the first outlet of the distribution valve during the first cycle with a first filter while back-flushing a second filter and filters at least some fluid output from the second outlet of the distribution valve during the second cycle with the second filter while back-flushing the first filter.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates in general to fluid filtering techniques, and in particular to filtering systems with integral filter back-flushing. 
       BACKGROUND OF INVENTION 
       [0002]    Fluid filtering technologies have been in existence for a very long time. Nevertheless, even the most sophisticated of these technologies are still subject to significant problems, including those related to the clogging and cleaning of the filters themselves. These problems are compounded when hazardous or toxic materials are involved, which make filter cleaning a difficult, and often hazardous, task. 
         [0003]    Consider for example a system for recovering water from a typical septic system used in residences, small business enterprises, and the like. In this case, waste water received from a sewer line is first received in a trash tank where solid organic waste materials settle-out. The remaining effluent is then moved to an aerobic tank, using either pumping or gravity flow, where air is pumped into the effluent to help breakdown the remaining organic matter. The effluent is then moved, using either Dumping or gravity flow, to a holding tank, where it is held and then periodically pumped out through a filter system to a leaching area. This leaching area can be, for example, a small plot of soil suitable for growing plants and can be serviced a drip irrigation system or similar means of water distribution coupled to the filter system. 
         [0004]    As with many types of fluid filtering systems, the filter between the holding tank and the leaching area can become clogged and therefore require cleaning. In a septic system, cleaning the filter can not only be a difficult task, but also a hazardous one, given the organic nature of the waste being handled. 
         [0005]    The need for more efficient fluid filtering systems suitable for a wide range of applications is generally desirable. Filtering techniques, which improve the efficiency and safety of systems handling potentially hazardous fluids, such septic system effluent, are particularly desirable. 
       SUMMARY OF INVENTION 
       [0006]    The principles of the present invention are embodied in filtering systems that perform automatic back-flushing without human intervention. According to one representative embodiment, a filter system is disclosed that includes a distribution valve operable to direct a received fluid stream to first and second outlets during respective first and second cycles. A filtering system filters at least some fluid output from the first outlet of the distribution valve during the first cycle with a first filter while back-flushing a second filter and filters at least some fluid output from the second outlet of the distribution valve during the second cycle with the second filter while back-flushing the first filter. 
         [0007]    Advantageously, the principles of the present invention provide for the design and construction of filtering systems that are subject to minimal clogging and/or that require minimal human intervention to maintain peak performance. Furthermore, when such filter systems are used in systems treating potentially hazardous materials, for example the effluent in septic systems, human exposure to such potentially hazardous materials is also minimized. Moreover, filter systems according to the inventive principles do not require electricity or a like power source to switch between operating cycles. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0009]      FIG. 1A  is a block diagram of a typical septic/waste water recovery system suitable for describing one application of the principles of the present invention; 
           [0010]      FIG. 1B  is a diagram illustrating another typical septic/waste water recovery system suitable for describing the inventive principles; 
           [0011]      FIGS. 2A-2C  are diagrams respectively showing top, side, and front-end views of a filtering system embodying the principles of the present invention and suitable for use in the systems shown in  FIGS. 1A and 1B ; 
           [0012]      FIGS. 3A and 3B  are more detailed diagrams of flush valves shown in  FIGS. 2A-2C ; and 
           [0013]      FIGS. 4A and 4B  are conceptual flow charts illustrating the operations of the filter system shown in  FIGS. 2A-2C . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The principles of the present invention and their advantages are best understood by referring to the illustrated embodiment depicted in  FIGS. 1-4  of the drawings, in which like numbers designate like parts. 
         [0015]      FIG. 1A  is a diagram of an exemplary septic/waste water recovery system  100  suitable for describing one particular application of the principles of the present invention, although these principles can be applied to a wide range of other fluid filtering systems. 
         [0016]    As shown in  FIG. 1A , system  100  includes an effluent input line  101 , which receives effluent from the drains of a house or small commercial concern. This effluent enters a trash tank  102  through trash tank inlet  103 . Generally, the effluent remains in trash tank  102  while organic solids settle-out. After settling, the remaining liquid effluent in trash tank  102  is transferred through outlet  104  and inlet  107 , using either pumping or gravity flow, into aerobic tank  105 , where a pump  106  pumps air into the effluent to help break down any remaining organic matter. 
         [0017]    Next, the effluent in aerobic tank  105  is transferred using either pumping or gravity flow through outlet  108  and an optional chlorinator  109  and into holding tank  110 . An irrigation pump  111 , controlled by a float  112 , pumps fluid from holding tank  110  through a line  113  to filter system  114 . Filter system  114 , which embodies the principles of the present invention, will be described in further detail below. In the preferred embodiment, float  112  enables the operation of irrigation pump  111  when sufficient fluid resides at the bottom of holding tank  110 . In addition, irrigation pump  111  includes a timer, such that when irrigation pump  111  is enabled by float  112 , irrigation pump  111  periodically pumps fluid through filter system  114  for a predetermined amount of time. 
         [0018]    In system  100 , the filtered water pumped through filter system  114  passes through a line or pipe  115  to drip irrigation field lines  116  (i.e. the disposal field in this example). In the illustrated embodiment, a back-flush valve/vacuum break  117  is provided between line  115  and drip irrigation field lines  116 . Return water flows through line or pipe  118  back through filter system  114  and line  119  into holding tank  110 . An additional line,  120 , allows water, which is used in the filter back-flushing operations described below and which potentially contains organic contaminates, to be returned to trash tank  102 . 
         [0019]      FIG. 1B  illustrates an alternate embodiment of septic system  100 , which uses an alternate configuration of filter system  114 . The two embodiments of system  100  shown in  FIGS. 1A and 1B  operate essentially the same way. 
         [0020]    A preferred embodiment of Filter  114  shown in  FIGS. 1A and 1B  is shown in particular detail in  FIGS. 2A-2C . Generally, filter system  114  includes at least two filtering subsystems, which provide fluid to the disposal area on alternate pump cycles. During at least a portion of each pump cycle, the filtering subsystem which is not being used to provide fluid to the disposal area is back-flushed to prevent clogging. 
         [0021]    The embodiment of filter system  114  shown in  FIGS. 2A-2C  is based upon an automatic distribution valve  201 . Automatic distribution value  201  is preferably a commercially available product, such at those available from K-Rain of West Palm Beach, Fla. 
         [0022]    Automatic distribution valve  201  includes Ports A and B, which are alternately coupled to the associated fluid pump (not shown). In particular, Port A is coupled to a first filtering subsystem, the primary components of which are a standard effluent filter  202   a , a check valve  203   a , a flush valve  204   a , and a check valve  205   a . A second filter subsystem, coupled to Port B of automatic distribution valve  201 , includes an effluent filter  202   b , a check valve  203   b , a flush valve  204   b , and a check valve  205   b . Advantageously, automatic distribution valve automatically  201  switches between Port A and Ports B on alternating pump cycles without the use of any electrical switching components. (It should be recognized that in alternate embodiments, automatic distribution valve  201  may have more than two (2) ports operating in multiple pump cycles to support a corresponding number of filter subsystems.) 
         [0023]    Each subsystem A and B includes interconnection components including sections of pipe or tube  206 , elbows  207 ,  21   1 , and  219 , unions  208 , flexible sections of tube or pipe  209 , T&#39;s  210 , reducing tees  212 , couplings  213 , reducing bushing spigots  214 , a 90 degree elbow  215 , a cross  216 , female adaptors  217 , and a reducing elbow spigot  218 . In the illustrated embodiment, each of these components is preferably made of PVC or similar material, although in alternate embodiments other materials, such as metal, may be used. System  100  also includes a 0-90 PSI pressure gauge  220 . 
         [0024]      FIG. 3A  is a more detailed diagram of a selected one of flush valves  204   a  and  204   b  of  FIGS. 2A-2C .  FIG. 3B  is a partial view taken along Line  3 B- 3 B of  FIG. 3A . 
         [0025]    The embodiment shown in  FIG. 3A  includes a tee  301  which couples to the corresponding conduit (pipe or tube)  211  shown in  FIG. 2B  through a bushing  311 . One arm of tee  301  couples through a bushing  302  to a conduit (tube or pipe)  308 , which is enclosed in a housing including a bushing  302 , a conduit (pipe or tube)  303 , couplings  304 , and a bushing  306 . Two buoyant plastic balls  305  are disposed within conduit  308 . 
         [0026]    The opposite side of conduit  308  is coupled through a tee  301  and a bull tee  314  to a hose adapter  315 . Hose adapter  315  in turn connects through a pressure controlled drain valve  316  and line  119  back to holding tank  110  of  FIGS. 1A and 1B . Bull tee  314  further couples through a barbed fitting  318  to a tube  319 , which in turn connects to cross-feed  228  of  FIG. 2A . In the illustrated embodiment, pressure controlled drain valve  316  opens when the pressure applied to bull tee  314  goes below 7 PSI. 
         [0027]    Tee  301  further couples through a conduit (tube or pipe)  313 , union  309 , elbow  310 , and bushing  311 , to a conduit (pipe or tube)  312 . Conduit  312  in turn connects through line  120  back to trash tank  102  of  FIGS. 1A and 1B . 
         [0028]    The operation of the preferred embodiment of filter system  114  shown in  FIGS. 2A-2C  and  FIGS. 3A-3B  is illustrated in  FIGS. 4A and 4B , which generally depict fluid flow for two alternating pump cycles. In particular,  FIG. 4A  shows a typical cycle (Pump Cycle  1 ) in which fluid is being output from Port A of automatic distribution valve  201 , subsystem A is providing fluid to the disposal area, and subsystem B is being back-flushed.  FIG. 4B  illustrates a typical cycle (Pump Cycle  2 ) in which fluid is being output from Port B of automatic distribution value  201 , subsystem B is providing fluid to the disposal area, and subsystem A is being back-flushed. In  FIGS. 4A and 4B , dashed lines indicate the movement of water, while solid lines indicate those portions of the system which are static (i.e. in which no fluid is flowing). 
         [0029]    As shown in  FIG. 4A , a portion of the fluid output from Port A of automatic distribution valve  201  flows through check valve  203   a  and through filter  202   a  in the forward direction. A portion of the fluid traveling through filter  202   a  goes on to the to the disposal area, while some of this fluid goes through filter  202   b  in the reverse direction, thereby back-flushing filter  202   b.    
         [0030]    Another portion of the fluid output from Port A of automatic distribution valve  201  flows through check valve  205   a . This fluid flow causes buoyant balls  305  of flush valve  204   a  to rise and close flush valve  204   a . At the same time, fluid through open check valve  205   a  begins to flow through tube  319  of bull tee  314  of flush valve  204   a  and cross-feed conduit  228 . (During Pump Cycle  1 , since no fluid is flowing through Port B of automatic distribution valve  201 , check valve  205   b  is closed.) 
         [0031]    The fluid flowing through cross-feed conduit  228  begins to force buoyant plastic balls  305  within flush valve  204   b  to rise. By controlling the diameter of cross-feed to tube  228 , the rate at which buoyant plastic balls  305  rise can be controlled, and hence the time during which flush valve  204   b  remains open. 
         [0032]    During the period in which buoyant balls  305  within flush valve  204   b  are rising, back-flushing fluid flowing through filter  202   b  is allowed to pass through flush valve  204   b  and back to trash tank  102  of  FIGS. 1A and 1B . Advantageously, any hazardous contaminates which have accumulated within filter  202   b  are flushed back into trash tank  102  without either leaving the system or coming in to human contact. 
         [0033]    Once buoyant plastic balls  305  of flush valve  204   b  reach the corresponding tee  301 , flush valve  204   b  turns off, and back-flushing of filter  202   b  stops. Fluid continues to be pumped through filter  202   a  and on to the disposal area during Pump Cycle  1 . 
         [0034]    At the end of Pump Cycle  1 , fluid flow through open check valve  205   a  stops, and hence no pressure is applied to pressure controlled drain valve  316  of flush valve  204   a . Additionally, the fluid flow through cross-feed tube  228  to flush valve  204   b  also stops. Consequently, without pressure being applied, pressure controlled drain valves  316  of both flush valves  204   a  and  204   b  open, and the fluid within the respective conduits  308  drains back into holding tank  110 . The corresponding buoyant plastic balls  305  fall and flush valves  204   a  and  204   b  are ready for Pump Cycle  2 . 
         [0035]    Pump cycle  2 , as shown in  FIG. 4B , proceeds similar to Pump Cycle  1  shown in  FIG. 4A . In this case, filter  202   b  is providing fluid to the disposal area, while filter  202   a  is being back-flushed under the control of flush valve  204   a.    
         [0036]    In an alternate embodiment, a ball valve or similar valve can be disposed within the fluid path of cross-feed  228  of  FIG. 2A  to control the back-flushing duration. This optional valve  401  is shown in broken lines in  FIGS. 4A and 4B . In particular, to decrease the rate of back-flushing, valve  401  is opened to increase the rate of flow into the given flush valve  204 , with the shortest back-flushing period resulting when valve  401  is fully open. On the other hand, to increase the rate of back-flushing valve  401  is closed to decrease the flow into the given flush valve  204 . 
         [0037]    Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
         [0038]    It is therefore contemplated that the claims will cover any such modifications or embodiments that fall within the true scope of the invention.