Abstract:
A water purification system for purifying water flowing through a water flow path. The system includes a water purification device having an inlet and an outlet in the water flow path and at least one interior volume communicating with the inlet and outlet. A purification medium is disposed within the interior volume of the water purification device. A flow control system is provided controlling a volume of purified water dispensed from the outlet. The flow control system includes an input device configured to allow a user to input a desired volume of purified water to be dispensed from the outlet and a sensing device coupled with the electronic input device and operative to determine the volume of purified water being dispensed from the outlet. A flow regulation device is coupled with the flow control system and operative to stop the discharge of purified water at the outlet upon reaching the desired volume of purified water.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to water purification systems and methods and, more specifically, to control systems used to sense and control a volumetric amount of water dispensed from the system. 
     BACKGROUND OF THE INVENTION 
     Water purification systems are used to provide high quality reagent grade water for various applications, including the field of scientific testing and analysis. Many of these applications require that the total organic carbon content of the water be on the order of 10 parts per billion or less ASTM. Type I water is the highest purity and is used for high performance liquid chromography, atomic absorption spectrometry, tissue culture, etc. Type II water is less pure and may be used for hematological, serological, and microbiological procedures. Type III water is suitable for general laboratory qualitative analyses, such as urinalysis, parasitology and histological procedures. Two prior systems for purifying water are disclosed in U.S. Pat. Nos. 5,397,468 and 5,399,263, each assigned to the assignee of the present invention. The disclosure of each of these patents is hereby incorporated by reference herein. 
     Purified water dispensing systems that currently provide automatic controlled dispensing of water do so using a timed dispense technique. This is accomplished by electronically controlling a solenoid valve and holding the solenoid valve open for a user-programmed time period. The user sets this time based on the amount of water they wish to dispense from the system. The user determines a relationship between dispensing time and flow rate for their specific system and operating conditions. Another method of controlling the dispensed amount of purified water involves manually opening a valve with the system pump shut off. Actuation of a switch in the valve initiates the pump when the valve is open. The pump remains energized for a time programmed by the user. When the time has expired, the pump is turned off by the control system. The manual valve remains open until the user returns to the system to close this valve. One significant drawback to this method is that the manual valve may remain open for some time until the user returns to shut it off. The main reason for using this method is to provide a manner of dispensing water into a larger vessel without holding a remote operating valve open for a long period of time and without running the water out of the vessel. Another drawback to both of these prior methods relates to the accuracy of the volume dispensed when relying on a user-defined relationship between dispensing time and dispensed volume. If the time value entered by the user is too long, the vessel being filled may run over. Generally, if the time value is incorrect by being either too long or too short, the user must manually correct the dispensed amount of water by removing water from the vessel or manually filling the vessel to the required amount. This, of course, defeats the purpose of having an automatic dispense control. The relationship between dispensed volume and dispensing time will also vary for any given system, depending on the pressure at the inlet of the system, the voltage on any pump associated with the system, the condition of the filters and membranes, among other factors. 
     In light of these and other problems in the art, it would be desirable to provide a water purification system having an accurate and automatic manner of sensing and, preferably, controlling the volume of water discharged from the system. 
     SUMMARY OF THE INVENTION 
     The present invention, in one aspect, provides a water purification system for purifying water flowing through a water flow path, and having a sensing device coupled with an electronic control for accurately indicating the volume of water dispensed from an outlet of the system. More specifically, the system includes a water purification device having an inlet and an outlet in the water flow path and at least one interior volume communicating with the inlet and outlet. A purification medium is positioned within the interior volume of the water purification device. The sensing device operates to generate a signal that is used to determine a volume of water dispensed from the outlet. The electronic control is coupled with the sensing device and includes an output responsive to the signal generated by the sensing device for indicating the volume of water dispensed from the outlet. The sensing device may comprise a flow sensor or, for example, a timer. The flow sensor may be coupled upstream of the inlet or downstream of the inlet, or at any other suitable location in the water flow path. The upstream position is preferred so that any contaminates from the sensor will be filtered out or purified by the purification device. If the sensing device is a timer, the timer is associated with a look-up table in the electronic control having time values usable to determine an amount of time for dispensing a desired volume of purified water from the outlet. Alternatively, the control may include an algorithm which is used in conjunction with the timer for dispensing the desired volume of purified water from the outlet. The control may further include an alerting device configured to alert the user when the desired volume of purified water has been dispensed from the outlet. 
     In the preferred embodiment, the control system includes an input device configured to allow a user to input a desired volume of purified water to be dispensed from the outlet. A flow regulation device is coupled with the control system and operative to stop the discharge of purified water at the outlet upon reaching the desired volume of purified water. 
     Various objectives, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of a water purifying system in accordance with the principles of the present invention; 
     FIG. 2 is a block diagram of a flow control system for use in the water purification system of FIG. 1; 
     FIG. 2A is a diagrammatic representation of the flow control system of FIG. 2; 
     FIG. 3 is a software flow diagram of the “AUTOMATIC DISPENSE ROUTINE” performed by the flow control system of the present invention; 
     FIG. 4 is a software flow diagram of the “TOTAL VOLUME DISPENSED ROUTINE” performed by the flow control system of the present invention; 
     FIG. 5 is a software flow diagram of the “CALIBRATION ROUTINE” performed by the flow control system of the present invention; and 
     FIG. 6 is a software flow diagram of the “SYSTEM CHECK ROUTINE” performed by the flow control system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings, and to FIG. 1 in particular, a water purification system  10  is illustrated in accordance to the principles of the present invention for dispensing a controlled volume of purified water as desired by a user. Water purification system  10  includes a fluid circuit or water flow path  12  having a water inlet  14  connected to a source of water (not shown), and a water outlet  16  for dispensing the controlled volume of water that has been purified by the system. As will be described in greater detail below, the fluid circuit  12  is preferably designed so that the volume of water entering inlet  14  corresponds to the volume of purified water dispensed at the outlet  16 . When purified water is not being dispensed at the outlet  16 , the fluid circuit  12  is preferably designed to recirculate the water through the circuit  12 . 
     Further referring to FIG. 1, water enters the inlet  14  of the fluid circuit  12  through a check valve  18 , a flow control system  20  and a pressure regulator  22 . As will be described in greater detail below, flow control system  20  is provided to allow a user to input a desired volume of water to be dispensed at the outlet  16 , and also to determine the volume of water dispensed from the water purification system  10 . A user interface  24 , including a user input  26  (FIG. 2) and user display  28  (FIG.  2 ), is coupled to the flow control system  20  for receiving user inputs as well as providing a display of information to the user. Pressure regulator  22  is provided to limit or regulate the pressure within the fluid circuit  12  to a predetermined value, such as 15 psi. A pump  30  is preferably connected in the fluid circuit  12  to circulate the water into through the circuit  12 . Pump  30  preferably has at least two operating speeds so that when purified water is not being dispensed from the system  10 , the pump  30  is set to operate at a predetermined “recirculation speed”. The speed of pump  30  is preferably increased to a predetermined “full speed” when purified water is being dispensed through the outlet  16  or through an optional remote dispensing gun  32  connected to the fluid circuit  12  as described in detail below. Alternatively, the pump  30  may have only a single operating speed, or the pump  30  may be eliminated and fluid circuit  12  may simply receive pressurized water through pressure regulator  22 . 
     As illustrated in FIG. 1, the water purification system  10  includes a water purification device  34  having an inlet and an outlet connected in the fluid circuit  12  and in fluid communication with at least one interior volume of the device  34 . The water purification device  34  is more fully disclosed in co-pending application Ser. No. 09/520,529, filed Mar. 8, 2000, and hereby fully incorporated herein by reference. 
     Briefly, water purification device  34  comprises a filter assembly  36  including a plurality of identically constructed cartridges  38   a-d  coupled in fluid communication with each other and with the inlet and outlet of the water purification device  34 . In operation, water circulating or passing through the fluid circuit  12  is directed through the filter assembly  36  or cartridges  38   a-d  as schematically illustrated in FIG.  1 . Purified water exiting from cartridge  38   d  moves past a sanitization port  40  which may be used to periodically inject a sanitent into fluid circuit  12  as necessitated by application requirements. A jumper  42  is provided for optionally connecting the remote dispensing gun  32  to the fluid circuit  12  as described in detail below. 
     Upon exiting the filter assembly  36 , the purified water enters a dispense manifold  44  connected in the fluid circuit  12 . The dispenser manifold  44  includes a first normally-closed solenoid valve  46  that is coupled to the flow control system  20 . The normally-closed solenoid valve  46  may be selectively opened by the user to direct water through a final filter  48  and through the water outlet  16 . When purified water is not being dispensed, a normally-open solenoid valve  50  is provided to direct the water in a recirculating manner through a check valve  52  and back to the beginning of fluid circuit  12  to be continuously recirculated by pump  30 . Check valve  52  prevents backflow from inlet  14  and also provides any necessary back pressure for a manual valve (not shown) associated with the optional remote dispensing gun  32 . 
     Flow control system  20  is the primary focus of the present invention and is illustrated according to a preferred embodiment in FIG.  2 . In accordance with one aspect of the present invention, flow control system  20  includes a vane-type flow sensor  54  that is coupled to a flow controller  56  of the flow control system  20 . Flow sensor  54  is operable to generate a signal that is used by the flow controller  56  to determine a volume of water dispensed from the water outlet  16 . The flow controller  56  provides an output that is responsive to the signal generated by the flow sensor  54  for indicating the volume of water dispensed from the outlet  16 . 
     The flow control system  20  of the present invention is provided to allow a user to input a desired volume of water to be dispensed at the outlet  16 , and also to determine the volume of water dispensed from the water purification system  10 . The user input  26  of the user interface  24  (FIG. 1) is preferably in the form of a control panel (not shown) that permits the user to simply enter the desired volume of purified water to be dispensed through outlet  16 . The user display  28  of user interface  24  (FIG. 1) is preferably in the form of an LCD or similar display that provides a user-readable indication of the volume of purified water dispensed, or to be dispensed, by the water purification system  10 . An optional alert  58  may be associated with the flow controller  56  to provide a visual and/or audible indication to the user when the desired volume of purified water has been dispensed. 
     In accordance with one aspect of the present invention as shown in FIG. 2, the flow sensor  54  includes a pulse generator  60  that is operable to generate a predetermined number of pulses in response to a predetermined volume of water dispensed through outlet  16 , such as 6,900 pulses for every liter of purified water dispensed through the outlet  16 . The flow controller  56  includes a pulse counter  62 , accumulated pulse counter  64  and memory  66  coupled to a microcontroller  68  for monitoring and controlling the volume of purified water dispensed through outlet  16 . It will be appreciated that while flow sensor  54  and flow controller  56  are illustrated as separate components, they may be combined into a single device without departing from the spirit and scope of the present invention. 
     Operation of the water purification system  10 , including the flow sensor  54  and flow controller  56 , will now be described in connection with monitoring and controlling the volume of purified water dispensed through outlet  16 . Flow controller  56  is operable to run the software routines of FIGS. 3-6 to perform the following functions: 1) automatically dispense a predetermined volume of water corresponding to a desired volume of water input into the flow controller  52  by the user through the user input  26 ; 2) monitor the volume and total volume of purified water dispensed by the water purification system  10 ; 3) calibrate the water purification system  10  to automatically dispense the desired volume of water input by the user; and 4) perform a system check to identify the presence of the remote dispense gun  32  or a leak in the system  10 . Those skilled in the art will appreciate that the software may reside in the memory  66  of the flow controller  56  and/or on tape, disc or diskette associated with the flow controller  56 , although the location of the software is not limited to the flow controller  56  as will be appreciated by those of ordinary skill in the art. 
     Referring now to FIG. 3, the “AUTOMATIC DISPENSE ROUTINE”  70  will now be described. The purpose of this routine is primarily to permit a user to input a desired volume of water to be dispensed by the water purification system  10 , and to control the system  10  to dispense the desired volume of water input by the user. Another purpose of this routine is to provide a user-readable display of the volume of water remaining to be dispensed through the outlet  16 . At step  72 , the flow controller  56  receives, through the user input  26 , the volume of water desired by the user to be dispensed through outlet  16 . At step  74 , the flow controller  56  calculates a pulse count corresponding to the desired volume of water, and sets the calculated pulse count in the memory  66 . For example, if the user desires one liter of purified water to be dispensed through the outlet  16 , the flow controller sets a pulse count value of  6 , 900  in the memory  66 . A determination is made at step  76  whether the user has pressed the “dispense key” to initiate automatic dispensing of the desired volume of purified water. If the “dispense key” has been pressed, the flow controller  56  resets the pulse counter  62  to zero at step  78  and sets the pump  30  to operate at “full speed” at step  80 . At step  82 , the flow controller  56  opens the normally-closed solenoid valve  46  associated with the dispense manifold  44  to dispense purified water through the water outlet  16 . As water is dispensed at the outlet  16 , flow sensor  54  is generating pulses through pulse generator  60  corresponding to the volume of water being dispensed. At step  84 , the pulse counter  62  of the flow controller  56  is counting the pulses generated by the pulse generator  60  of the flow sensor  54 . A decision is made at step  86  whether the pulse count generated by the pulse generator  60  equals the pulse count set in memory  66 . If not, the pulse counter  62  continues to count the pulses generated by the pulse generator  60 . However, if the generated pulse count does equal the pulse count set in memory  66 , the flow controller  56  closes the solenoid valve  46  at step  88  to stop discharge of water through the outlet  16 , and resets the pump  30  to its “recirculation speed” at step  90 . 
     Further referring to FIG. 3, as the pulse counter  62  is counting pulses generated by the pulse generator  60 , the flow controller  56  subtracts the present pulse count from the pulse count set in memory  66  and converts the pulse count remainder to a volume of water remaining to be dispensed, as indicated at step  92 . The flow controller  56  provides a display of the volume of water remaining to be dispensed on the user display  28 , as indicated at step  94 . While not shown, it will be appreciated by those of ordinary skill in the art that the flow controller  56  could convert the present pulse count to a volume of water actually dispensed, and display that information to the user as well on the user display  28 . When the desired volume of purified water has been dispensed, the flow controller  56  will actuate alert  58  to provide an indication to the user that the dispense cycle is completed. It will be appreciated that the “AUTOMATIC DISPENSE ROUTINE”  70  permits the user simply to input a desired volume of water to be dispensed, and thereafter accurately controls the dispensed volume of water to correspond to the desired volume input by the user. 
     With reference now to FIG. 4, the “TOTAL VOLUME DISPENSED ROUTINE”  95  will be described. The purpose of this routine is to monitor the total volume of purified water dispensed by the water purification system  10 , and to provide this information to the user for various service, billing, warranty and usage-type purposes. In particular, at step  96 , a volume of purified water is dispensed through the outlet  16 . At step  98 , the pulse generator  60  associated with the flow sensor  54  generates a series of pulses that are counted by the pulse counter  62 , as well as by the accumulated pulse counter  64 , of the flow controller  56 . At step  100 , the accumulated pulse counter  64  stores and accumulates the pulses generated by the pulse generator  60  over multiple dispensing operations of the water purification system  10 . At step  102 , the flow controller  56  converts the accumulated pulses counted by the accumulated pulse counter  64  to a total volume of purified water dispensed by the water purification system  10 . As indicated at  104 , this information may be used as service information to inform the user when service or maintenance of the system  10  is required. The service or maintenance may include changing the filter assembly  36  or injecting a sanitant into the fluid circuit  12  through the sanitization port  40 , for example. As indicated at  106 , the total volume of water dispensed by the water purification system  10  may also be used for billing information so that the user may be accurately charged for the volume of purified water dispensed by the system  10 . As indicated at  108 , this information may also be used for warranty information or, as indicated at  110 , for usage-type information, such as the total volume of water that has been dispensed through the a particular water purification system  10  over a predetermined period of time. 
     Referring now to FIG. 5, the “CALIBRATION ROUTINE”  112  will now be described. The purpose of this routine is to calibrate the water purification system  10  to accurately dispense the desired volume of purified water at the outlet  16 . At step  114 , a determination is made whether the flow controller  56  has been set to operate in a “calibration mode”. If yes, a determination is made at step  116  whether the user has depressed the “dispense key”. If the user has depressed the “dispense key”, the flow controller  56  dispenses a predetermined volume of purified water corresponding to a predetermined pulse count. For example, at step  118 , if the flow controller  56  is set to operate in “calibration mode” and the “dispense key” has been pressed, the flow controller  56  may be programmed to dispense a liter of purified water corresponding to a pulse count of 6,900. As indicated at  120 , the user measures the actual volume of water dispensed, and inputs that value into the flow controller  56  through the user input  26  at step  122 . At step  124 , the flow controller  56  calculates an error corresponding to the difference between the predetermined volume of water to be dispensed in “calibration mode” and the actual volume of water dispensed at the outlet  16 . Thereafter, at step  126 , the flow controller  56  increments or decrements the predetermined pulse count to obtain the predetermined volume of water that should be dispensed when the “dispense key” is pressed and the flow controller  56  is set to operate in “calibration mode”. For example, it may be determined through the “CALIBRATION ROUTINE”  112  that one liter of dispensed purified water actually corresponds to a pulse count of 6,985 instead of 6,900. By calibrating the pulse count to correspond to the actual volume of water dispensed, all following automatic dispense cycles should be very accurate. 
     Referring now to FIG. 6, the “SYSTEM CHECK ROUTINE”  128  will now be described. The purpose of this routine is to determine either the connection of the remote gun  32  to the fluid circuit  12  or a leak in the system  10 . At step  130 , a determination is made whether the “dispense key” has been depressed. If yes, control is passed to the “AUTOMATIC DISPENSE ROUTINE”  70  as described above. If not, a determination is made at step  132  whether a pulse has been detected by the pulse counter  62  associated with the flow controller  56 . If a pulse is detected at step  132 , the pulse counter  62  counts the pulse at step  134 . At step  136 , the flow controller  56  determines whether the pulse count of pulse counter  62  is greater than a predetermined pulse number stored in memory  66 . If the pulse count exceeds the predetermined pulse number stored in memory  66 , a determination is made at step  138  whether the remote gun  32  is present. This information may be provided through a query of the user to verify that the remote gun  32  is or is not connected to the fluid circuit  12 . If the user indicates at step  138  that the remote gun  32  is not present, flow controller  56  shuts off pump  30  at step  140 , and may also cause the water purification system  10  to be disconnected from the water source (not shown) at step  142 . Thereafter, the flow controller  56  may provide a display warning to the user on user display  28  to warn the user to check for a leak in the system  10  at step  144 . 
     If a determination is made at step  138  that the remote gun  32  is connected to the fluid circuit  12 , the flow controller  56  turns the pump  30  to “full speed” at step  146 . A determination is made at step  148  whether a pulse is detected by the pulse counter  62 , indicating that purified water is being dispensed through the remote gun  32 . If no pulse is detected at step  148 , indicating that the valve (not shown) of the remote gun  32  has been closed, the flow controller  56  resets the pump  30  to operate at its “recirculation speed” at step  150 . 
     While a vane-type flow sensor  54  is shown in the preferred embodiment of FIG. 2, it will be appreciated that other sensing devices are possible without departing from the spirit and scope of the present invention. For example, the sensing device may have a voltage or current output rather than a pulse output as described in detail above. Moreover, while a vane-type flow sensor has been described in detail, it will be appreciated that the flow sensor may comprise an ultrasonic, paddlewheel or similar flow sensor readily known by those of ordinary skill in the art. Additionally, and as illustrated in FIG. 2A, the sensing device may include a timer and look-up table  152  or timer and algorithm  154  associated with the flow controller  56 . For example, as indicated at  158  in FIG. 2A, the user may input a desired volume of purified water to be dispensed by system  10  through the user input  26 . In the event the sensing device comprises a timer and look-up table  152 , the flow controller  56  includes a look-up table that correlates a desired volume of purified water input by the user to a dispense time corresponding to opening of the normally-closed solenoid valve  46 . In this embodiment, the user&#39;s input of the desired volume of purified water to be dispensed by the system  10  is converted by the sensing device  152  into a time value for opening the normally-closed solenoid valve  46 . In this way, the water purification system  10  discharges a desired volume of purified water input by the user as indicated at  160 . 
     Alternatively, when the sensing device is a timer and algorithm, the flow controller  56  converts the user&#39;s input of the desired volume of purified water to be dispensed into a time value for opening the normally-closed solenoid valve  46 . The time value is computed in the algorithm by dividing the desired volume of purified water input by the user by the known flow rate of the system  10 . 
     It will be appreciated by those of ordinary skill in art that while the flow control system  20  has been described as being positioned upstream of the inlet to the water purification device  34 , the flow control system may alternatively be positioned downstream of the outlet of the water purification device  34  without departing from the spirit and the scope of the present invention. 
     While the present invention has been illustrated by a description of these preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. This has been a description of the present invention, along with the preferred methods of practicing the present invention as currently known. Various aspects of this invention may be used alone or in different combinations.