Abstract:
The present invention provides a method and system of anticipating salt depletion in a brine tank of a water softener system, the system including a controller having a user interface and display, the method comprising the steps of tracking salt usage; determining the amount of salt remaining in the brine tank; calculating the number of days before salt is required in the brine tank based on salt usage and the amount of salt remaining in the brine tank; and providing an indication of the number of days to empty, whereby a user is able to anticipate the need to replenish the salt supply and plan accordingly to assure continuous satisfactory operation of the water softener system.

Description:
FIELD OF THE INVENTION 
     The invention relates, generally, to water softeners and, more particularly, to a system and method for anticipating salt depletion. 
     BACKGROUND OF THE INVENTION 
     Domestic water softeners remove hardness from raw water by passing it through a tank containing a liquid treatment medium bed, typically formed of resin beads. A salt solution, that is brine, is passed through the resin bed to restore its softening capacity. The brine is formed in a container which is connected by a liquid flow passage to the tank containing the resin beads. The flow of liquid through the liquid flow passage is regulated by a control valve which is actuated by an electronic regeneration control circuit. 
     Salt, typically in the form of chunks or pellets, is placed in the container. Under the control of the electronic regeneration control circuit, the control valve allows a predetermined amount of water to enter the container. Provided enough salt is present, the water and salt form a saturated salt solution, or brine, which is the regenerant for the resin bed. Again, under the control of the electronic regeneration control circuit, the control valve is actuated to cause the brine to be withdrawn from the container and circulated through, and thereby regenerate, the resin in the tank. 
     The amount of salt remaining in the container is reduced each time a portion of the salt is dissolved to form a regenerant. The supply of salt will become exhausted after a number of regeneration cycles, unless additional salt is placed in the container. Such that the salt supply will not become exhausted, it is desirable to provide some type of alarm to indicate that the salt supply is close to being exhausted. Such an alarm may be formed as a part of the electronic regeneration control circuit. 
     U.S. Pat. No. 5,363,087 is assigned to the instant assignee and discloses an example of an apparatus which detects a low level of salt and generates a corresponding low salt level alarm and is incorporated herein by reference. U.S. Pat. No. 5,363,087 discloses an apparatus for providing a regeneration solution to a regenerable liquid treatment medium bed including an electronic regeneration control circuit for controlling the regeneration of a liquid treatment medium bed with regenerant solution formed in a container by dissolving a quantity of solid material in a liquid. The container in which the regenerant solution is formed is provided with indicia spaced apart in a vertical direction. The indicia are observable with respect to the top surface of the quantity of solid material received in the container. An electronic control circuit includes a manual input means for entering the amount of solid material available in the container in terms of the observed indicia most closely corresponding to the top surface of the solid material. The electronic control circuit includes means for electronically reducing, each time a quantity of regenerant solution is used to regenerate the liquid treatment medium, the electronically stored indication of the amount of solid material remaining in the container. The apparatus includes an alarm means which is actuated to provide an alarm when the electronically stored indication of the amount of solid material remaining in the container is less than a predetermined minimum amount. 
     U.S. Pat. No. 5,544,072, incorporated herein by reference, is assigned to the instant assignee and discloses a method for regeneration of a water softener including a method to determine when a regeneration should occur. 
     The prior art systems indicate or warn when a water softener unit is low or out of salt. A user must be ready to immediately replenish the salt supply, lest there be an interruption of service. A user must provide an overstock of salt in order to avoid such an interruption of service. An interruption of service maybe an inconvenience, but also carries a greater significance if the softener has been used to remediate any health effects such as the removal of barium or radium that may be in the water being treated. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a water softener with the ability to more accurately provide the status of the amount of remaining salt and avoid interrupted service. 
     It is a further object of the invention to provide a water softener which anticipates when salt should be added. 
     It is still a further object of the invention to provide a water softener which provides a user with an indication, in advance, when salt will be required. 
     Accordingly, the present invention provides a method of anticipating salt depletion in a brine tank of a water softener system, the system including a controller having a user interface and display, the method comprising the steps of (a) tracking salt usage; (b) determining the amount of salt remaining in the brine tank; (c) calculating the number of days before salt is required in the brine tank based on salt usage and the amount of salt remaining in the brine tank; and (d) providing an indication of the number of days to empty, whereby a user is able to anticipate the need to replenish the salt supply and plan accordingly to assure continuous satisfactory operation of the water softener system. 
     In one embodiment, the method of tracking salt usage includes tracking the average salt per regeneration, the average number of days between regeneration and the number of days since the last regeneration. The salt level value of step (a) is received via a user entering the value into the system via a user interface. The step of determining or recalculating the number of days before salt is required in the brine tank is based on the salt level value is done using the formula, A/B*C−D, wherein: 
     A=the salt level value; 
     B=the average salt per regeneration; 
     C=the average days between regenerations; and 
     D=the number of days since the last regeneration. 
     The present invention also provides a system for anticipating salt depletion in a brine tank of a water softener, the system having means for tracking salt usage; means for determining the amount of salt remaining in the brine tank; means for calculating the number of days before salt is required in the brine tank based on salt usage and the amount of salt remaining in the brine tank; and means for providing an indication of the number of days to empty, whereby a user is able to anticipate the need to replenish the salt supply and plan accordingly to assure continuous satisfactory operation of the water softener system. In one embodiment, the system includes means for recalculating the number of days before salt is required in the brine tank, in the event salt has been added to the brine tank, a regeneration has occurred, or another day has passed since the last regeneration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a water softener and system for monitoring the status of the water softener, in accordance with the present invention. 
     FIG. 2 is a block diagram of the water softener and system of FIG.  1 . 
     FIG. 3 is a perspective of the display panel of the water softener of FIG.  1 . 
     FIG. 4 is a partial view of the display panel with the salt level option selected. 
     FIG. 5 is a block diagram of a portion of a control circuit in accordance with a preferred embodiment of this invention. 
     FIG. 6 is a flowchart of the days to empty feature of the present invention. 
     FIG. 7 is a flowchart of the alarm indication feature of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, this invention will be described as embodied in a water softener wherein the water softening system includes a salt container or tank  10  and a resin tank  12 . The salt storage container is provided with a cover  14 . The resin tank  12  is provided with a cover  16  which supports a housing  18  enclosing an electronic regeneration control circuit. The front face of the electronic control circuit housing  18  is provided with display and control panel  20 . The cover  14  includes a removable lid  22  which is provided primarily for the purpose of permitting salt to be placed in the salt storage container. The salt storage container and the electronic control circuit are appropriately connected by a tube and electrical conductors to the resin tank and an electronically operated control valve respectively. 
     A brine well  24  is placed within the salt storage container  10 . Placed within the brine well  24  is a conduit (not shown) which extends to near the bottom of the salt storage container  10 . A tube  26  connects the conduit to the appropriate connection on the control valve. Openings  28  are provided at the bottom of the brine well  24  such that water may flow out of the brine well  24  and brine into the brine well  24 . However, the opening  28  are sized such that solid particles, particularly salt, are prevented from entering the brine tank. 
     Under the control of the electronic control circuit, the control valve permits a predetermined amount of water to flow through the tube  26 , conduit, and openings  28  in the brine well  24  into the brine tank. The flow of water into the brine well  24  may also be terminated by a float valve associated with the conduit and located in the brine well. As demanded by the electronic control circuit, the control valve is actuated to withdraw brine from the brine tank through the openings  28  in the brine well  24 , the conduit and the tube  26  by a venturi pumping action. 
     In accordance with the embodiment of this invention shown in FIG. 1, indicia  30  are provided in association with the brine tank or container in such a manner as to be readily observable with respect to the top surface of the salt in the tank by removing the lid  22 . As shown in FIG. 1, the indicia  30  are integrally formed on the inside surface of the container  10 . However, the indicia  30  could be formed on the sidewall of the resin tank  12 , if the tank  12  were located within the salt storage container  10 , in such a position for the indicia  30  to be readily visible when the lid  22  is removed. The indicia  30  could, of course, be provided on the sidewall of the salt tank  10  in other ways, such as by providing a separately formed measurement strip similar to a ruler or yardstick, having the indicia  30  formed thereon, which strip being secured to the sidewall of the salt tank  10 . While the indicia  30  may be provided in many different ways, they should, of course, be provided in a form which is not attacked by the corrosive atmosphere resulting from the brine contained within the tank. In the preferred embodiment of this invention, the indicia  30  are spaced apart in a vertical direction such that the space between adjacent indicia  1  through  9  represents one-tenth of the total salt capacity of the tank. 
     The water softener may include a remote unit  32  having a display panel  34 . The status information of the present invention, as described in detail below, may be provided to a remote location via the remote user. U.S. Pat. No. 5,774,529 discloses an example of such remote operation, and is incorporated herein by reference. 
     With reference to FIG. 2, water softener preferably includes a source pipe  36 , connected to a source  38  of hard water, a destination pipe  40 , connected to a destination  42  intended to use the softened water, and a drain pipe  44  connected to a drain  46 . Pipes  36 ,  40 ,  44  are also connected to a control valve  48 . A resin bed  50 , preferably comprising particles of ion exchange resin, is disposed in a resin tank  52 . A pipe  54  and a pipe  56  connect resin tank  52  to control valve  48 . A brine tank  58  holds a quantity of a regenerant salt  60 , typically NaCl or KCl, and is connected to an aspirator valve  62  by a pipe  64 . Pipe  64  includes a brine valve  66 . Alternatively, and preferably, the brine valve is located in the brine tank  60 . Pipes  68 , 70  connect aspirator valve  62  to control valve  48 . Control valve  48  may be configured to interconnect pipes  36 ,  40 ,  44 ,  54 ,  56 ,  68 ,  70  in a number of different ways hereinafter described. 
     The water softener preferably includes a micro computer controller  72  and a user interface  74  having the display and control panel  20 . A timer  76  is provided to enable controller  72  to measure time durations. A water meter  77  is placed in either pipe  36 , or preferably pipe  40 , to enable controller  72  to measure the amount of water flowing through resin tank  52 . Controller  72  sets the configuration of control valve  48 . 
     When in service, hard water from source  38  passes through supply pipe  36  to control valve  48 , which is configured so that the hard water then flows through pipe  54  to resin tank  52 . In resin tank  52  the hard water passes through resin bed  50 , where it is softened by an ion exchange process. The soft water flows out from resin tank  52  through pipe  56  to control valve  48 . Control valve  48  is configured to direct the soft water from pipe  56  to pipe  40 , where it is directed to its destination  42 . 
     When the resin bed  50  loses its capacity to effectively soften the water passing through it, regeneration is necessary. The regeneration cycle preferably includes the following steps: (1) fill; (2) brine draw; (3) slow rinse; (4) backwash; and (5) fast rinse. During the fill step, a quantity of water flows into brine tank  58  to dissolve a quantity of the salt therein in order to make the amount of brine necessary for regeneration. Specifically, control valve  48  is configured so that hard water from source  38  flows through pipe  36  to pipe  54  to resin tank  52 . The hard water passes through resin bed  50  and flows out through pipe  56  to control valve  48 . Control valve  48  is configured to direct this water to pipe  68  and then to pipe  64  through aspirator valve  62 . Brine valve  66  opens in response to the flow of water in pipe  64 , allowing the water to enter brine tank  58 . The water filling brine tank  58  dissolves a quantity of the salt to form a brine. The duration of the fill step determines the amount of water that enters brine tank  58  and therefore the amount of regenerant salt dissolved and available for regeneration. 
     During the brine draw step, control valve  48  is configured so that hard water from pipe  36  is directed to pipe  68 , whereupon it flows through aspirator valve  62  to pipe  70 . This flow through aspirator valve  62  creates suction on pipe  64  by the Venturi effect. Brine valve  66  is open, so that the suction on pipe  66  draws the brine in brine tank  58  formed during the fill step, up into pipe  64 , which then flows through aspirator valve  62  to pipe  70 . Control valve  48  is configured so that the water and brine from pipe  70  are directed through pipe  54  to resin tank  52 . The brine entering resin tank  52  flows through resin bed  50 , thereby regenerating it, and flows out through pipe  56  as waste. Alternatively, and preferably, the flow of brine is to pipe  56 , then through resin tank  52 , and out pipe  54 . The waste is directed to drain  46  via pipe  44  for its disposal. The duration of the brine draw step is sufficiently long so as to withdraw all or nearly all of the brine from brine tank  58 . Preferably, a brine valve in brine tank  58  closes automatically when the level of brine in brine tank  58  falls below a prescribed point. 
     During the slow rinse step, the brine valve is closed, and brine is no longer withdrawn from brine tank  58 . However, water keeps flowing as in the brine draw step. In particular, the configuration of control valve  48  is the same as for the brine draw step. The remaining brine continues to flow through resin bed  50  until replaced with incoming water in order to achieve maximum ion exchange and to continue to flush out any hardness minerals or brine which may remain in resin tank  52 . 
     During the backwash and fast rinse steps, control valve  48  is configured so that hard water from pipe  36  is directed so that the water flows through the resin bed  50  and is directed to drain  46  via pipe  44 . During the backwash step, the water flows up through resin bed  50 , lifting up and expanding the resin bed and flushing out iron minerals, dirt, sediments, hardness minerals, and any remaining brine. During the fast rinse step, a fast flow of water is directed downward through resin bed  50  to pack it and prepare it for service. 
     Controller  72  determines when to regenerate resin bed  50  and to what capacity. Various methods may be used for these determinations, such as those described in U.S. Pat. Nos. 5,544,072 and 4,722,797. The necessary capacity will, in general, depend on the hardness of the water to be treated. User interface  74  therefore preferably includes means by which the user can enter the water hardness, expressed in grains per gallon, into controller  72 . To accommodate the use of different types of regenerant salt, user interface  74  also enables the user to specify the type of salt used, e.g., whether NaCl or KCl is used. 
     The water softener also includes a transmitter  78  for transmitting status information to the remote unit  32 . The remote unit includes a receiver  80  coupled to a remote controller  82  which in turn is coupled to the display panel  34 . 
     Provided on the display and control panel  20  of the softener system are manual input means for inputting salt levels as observed with respect to the indicia  30  and a user display  84 . Referring to FIGS. 1,  3  and  4 , the control manual input means includes a salt increase key  86 , a salt decrease key  88 , a salt level display, shown as a bar indicator  90  and a numerical display  92 , an alarm indicator, such as an LED indicator  94  or an audio buzzer  96 , and a days to empty indicator  98 . The display panel  34  of the remote unit  32  also provides a user display  84 . 
     Referring to FIG. 5, the controller  72  is shown to include a CPU  100  and a memory  102 . The user interface  74  includes the control and display panel  20 . FIG. 5 shows the connections of the control and display panel  20  to the controller  72 . Inputs to the central processing unit  100  include the salt increase key  86 , the salt decrease key  88 , the meter  77 , a recharge key  104  and a program key  106 . Outputs of the controller  72  include the salt level display bar  90 , the salt level display  92 , the low salt indicator  94 , the low salt buzzer  96  and the days to empty display  98 . The operation of the circuit shown in FIG. 5 is in accordance with the flow charts of FIGS. 6 and 7. It should be understood that only those aspects of the electronic regeneration control circuit directly relating to this invention are shown in FIG.  5 . The microcomputer also has other inputs, such as time of day, usage of processed water, etc. and also additional outputs such as those controlling the control valve. 
     With reference to FIG. 3, the program button  106  is used to navigate through the options and information available to the user. The selected item can then be changed with the UP/DOWN buttons. For example, from a default display, the program button  106  may be used to access the primary level options which include the Set Salt Level, Set Present Time, Set Hardness and Set Recharge Time. If the salt level option is selected such as shown in FIG. 4, the UP/DOWN buttons function as the salt increase key  86  and the salt decrease key  88 , respectively. As the salt level is adjusted by the user, the salt level bar display  90  and the salt level numerical display  92  change accordingly. 
     In one embodiment, inside the brine tank, nine levels ( 0 - 8 ) are indicated via the indicia  30 . Each level corresponds to one bar on the Salt Level bar display  90 . The user adjusts the salt level bar to match the indication inside the brine tank  10  after adding salt. Press and release the UP or DOWN button to have the number displayed increase or decrease by 0.5. The salt bars are incremented or decremented on whole numbers. Holding the UP or DOWN button causes the bars to increase or decrease at a rate of 1 bar every second. After adjusting the Salt Level Bars, the controller  72  assumes the salt is at the level indicated (in ½ increments) inside the container  10 . 
     The recharge button  104  has two different functions. The first function schedules a regeneration to occur at the next recharge time. The second function causes a regeneration to begin immediately. 
     The DAYS TO EMPTY information is displayed when the controller  72  is in the default display. The purpose of this feature is to inform the owner, the number of days before the Salt Level in the brine tank or container  10  reaches level  0 . The level is updated daily at a set time, such as at midnight, and whenever the Salt Level value is modified. 
     The formula used to calculate the DAYS TO EMPTY (DTE) is shown in the following table. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                 DTE = (A/B) × C − D 
               
             
          
           
               
                   
                 Wherein, 
               
               
                   
                 A = total salt remaining in the brine tank 
               
               
                   
                 B = the average salt used per regeneration based on 70% of the 
               
               
                   
                 old average and 30% of the salt used in the last regeneration 
               
               
                   
                 C = the average days between regenerations based on 70% of the 
               
               
                   
                 old average and 30% of the number of days between the last two 
               
               
                   
                 regenerations 
               
               
                   
                 D = the number of days since the last regeneration 
               
               
                   
                   
               
             
          
         
       
     
     FIG. 6 discloses one embodiment for the DAYS TO EMPTY feature of the present invention. After the start step  108 , there is a decision branch  110  to determine whether it is the pre-programmed recharge time (i.e., midnight). In the event it is not the recharge time, the program continues to the Salt Level modified Decision Branch  112 . At the Salt Level Modified Decision Branch  112 , it is determined whether the Salt Level has been modified, such as by the user input. In the event the Salt Level has not been modified, the program continues with the flowchart shown at FIG.  7  and eventually returns to the start  108  of the flowchart of FIG.  6 . In the event the Salt Level has been modified, the program continues with the recalculate A step  114 . At the recalculate A step  114 , the total salt remaining is recalculated based on the modified Salt Level. The program then continues with the recalculate DTE step  116 . The recalculate DTE step  116  recalculates the number of days to empty, taking into consideration the modified total salt remaining. 
     In the event it is determined that it is the recharge time at the recharge time Decision Branch  110 , the program continues with the recharge Decision Branch  118 . The process for deciding whether it is time for a recharge is known in the prior art. In the event it is determined that it is time for a recharge, the program continues with the recharge step  120 . After the recharge has been conducted, the program continues with the recalculate A step  122 , wherein the total salt remaining is recalculated based on the salt used during the recharge. The program then continues with the recalculate B step  124 , wherein the average salt per regeneration is recalculated based on the salt used in the last regeneration. The program then continues with the recalculate C step  126 , wherein the average days between regenerations is recalculated based on the number of days between the last two regenerations. The program then continues with the D=0 step  128 , wherein the number of days since the last regeneration is reset to 0. The program then continues with the recalculate DTE step  116 , wherein the days to empty is recalculated based on the foregoing adjustments. The program then branches at step  130  to the flow chart of FIG.  7 . 
     In the event it is determined at the recharge Decision Branch  118  that it is not time for a recharge, the program continues with the D=D+1 step  132 . The D=D+1 step  132  increments the number of days since the last regeneration. The program then continues with the recalculate DTE  116 , wherein the days to empty is recalculated based on an additional day elapsing without a regeneration having occurred. 
     FIG. 7 discloses the program for indicating when a days to empty limit has been reached. When the limit has been reached, a visual and audio indication may be provided as described in the following example. The example assumes a DTE limit of 15 days. However, it will be appreciated that the limit could be greater or less than 15 days. In the example, when the DAYS TO EMPTY value is 15 or less the Low Salt LED  94  will flash at a rate of 1 flash every second. If at this time, the Low Salt Buzzer option is on, the buzzer  96  will alert the user of the condition by emitting one 600-millisecond beep every 30 seconds between 8 am. and 8 pm. After the user presses any key, the Low Salt LED  94  will continue to flash (once per second), and the beeping sequence is discontinued. A screen showing the user that the buzzer  96  has been turned off will be displayed while the key is being pressed. The Low Salt LED  94  will continue flashing and the buzzer  96  will remain quiet until the user sets the Salt Level to a value that will predict a days to empty value greater than 15. At this point, the Low Salt LED  94  will go back to its normal on (solid) condition and the buzzer  96  will be ready to sound again when the DAYS TO EMPTY value is 15 or less. 
     The program begins with step  134  which is a branch from step  130  of FIG.  6 . The program continues with the Decision Branch  136  to determine whether the days to empty limit has been reached. In the event the limit has not been reached, the program continues on to the return step  138 . If the limit has been reached, the program continues with the flash LED step  140 . Thereafter, the program continues with the Decision Branch  142  to determine whether the Low Salt Buzzer is on. In the event the buzzer is not on, the program continues to the return step  138 . If the buzzer is set, the program continues with the Decision Branch  144  to determine whether the user has cancelled the Low Salt Buzzer Alarm. In the event the user has cancelled the alarm, the program continues with the return step  138 . In the event the use has not cancelled the alarm, the program continues with the buzzer step  146 . At the buzzer step  146 , the program activates the buzzer 0.6 seconds, every 30 seconds between 8 am. and 8 pm., or as otherwise programmed, or until the user presses a key, such as the program key  106 , to acknowledge the buzzer indication. 
     While preferred embodiments of the present invention have been illustrated and described, it will be understood by those of ordinary skill in the art that changes and modifications can be made without departing from the invention in its broader aspects. Various features of the present invention are set forth in the following claims.