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CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Applications No. 60/289,159 filed May 7, 2001 and No. 60/311,472 filed Aug. 10, 2001. 
     
    
     
       REFERENCE REGARDING FEDERAL SPONSORSHIP  
         [0002]    Not Applicable  
         REFERENCE TO MICROFICHE APPENDIX  
         [0003]    Not Applicable  
           [0004]    1. Field of the Invention  
           [0005]    The present invention relates to a device and method for monitoring the flow of liquids and, more particularly, for monitoring the flow of urine in a urinal, such as a waterless urinal, to determine when a trap cartridge needs to be changed or serviced.  
           [0006]    2. Description of Related Art and Other Considerations  
           [0007]    Waterless urinals, such as are disclosed in U.S. Pat. No. 6,053,197 and U.S. patent application, Ser. No. 09/855,735 (filed May 14, 2001), typically use a water trap in which a low density sealant layer covers a small amount of wastewater remaining in the urinal trap. Such urinals conventionally do not have a flush mechanism; therefore, some amount of wastewater will remain in the trap at all times. The sealant layer prevents odors from escaping from and through the wastewater. Any slow draining of wastewater from the trap or blocking within the trap or sufficient use of the urinal to cause the supply of sealant to be significantly diminished, will result in unpleasant odors. Therefore, it is important for such urinals to be cleaned and serviced regularly, and especially when draining slowly, and a need exists for determining when the conditions for cleaning and servicing pertain.  
         SUMMARY OF THE INVENTION  
         [0008]    These and other problems are successfully addressed and overcome by the present invention, along with attendant advantages. The present invention employs an electric device, including a PROM and associated algorithm, to monitor urine flow through the cartridge trap. Measuring the duration of such flow and the number of times the urinal is used will determine, in accordance with preset criteria, when servicing or replacement is needed, and alerts a janitor or repairman or other service person by a warning light or other signal. Because urine has a high mineral content, it is electrically conductive, effective to complete circuits between closely spaced metal contacts coupled to the PROM, which allows the manner and existence of the urine to be detected.  
           [0009]    Other aims and advantages, as well as a more complete understanding of the present invention, will appear from the following explanation of an exemplary embodiment and the accompanying drawings thereof. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective view of the present invention depicting a removable trap utilized in a urinal with a liquid flow meter installed therein;  
         [0011]    [0011]FIG. 2 is a cross-sectional view of the present invention illustrated in FIG. 1;  
         [0012]    [0012]FIG. 3 is a perspective view of the liquid flow meter taken from its exterior or cover;  
         [0013]    [0013]FIGS. 4 and 5 are side views of the exterior or cover of the liquid flow meter, with one taken 90° from the other;  
         [0014]    [0014]FIG. 6 is an electric schematic diagram of the of the liquid flow meter;  
         [0015]    [0015]FIG. 7 is an exploded perspective view of the present invention;  
         [0016]    [0016]FIG. 8 is a perspective view of the liquid flow meter depicted in FIG. 3 with its outer cover removed to disclose the interior components thereof;  
         [0017]    [0017]FIG. 9 is a top view of the liquid flow meter;  
         [0018]    [0018]FIG. 10 is a bottom, upwardly looking view of the liquid flow meter, taken 90° from that depicted in FIG. 9;  
         [0019]    [0019]FIGS. 11 and 12 are side views of the liquid flow meter, with one view being taken 90° from the other;  
         [0020]    [0020]FIGS. 13 and 14 are perspective views of the respective negative and positive battery clips used in the liquid flow meter illustrated in FIGS.  7 - 11 ;  
         [0021]    [0021]FIG. 15 is a perspective view of the sensor contact clips employed in the liquid flow meter illustrated in FIGS.  8 - 12 ;  
         [0022]    [0022]FIG. 16 is a logic flow chart depicting the algorithm utilized in operating the liquid flow meter of the present invention; and  
         [0023]    [0023]FIG. 17 is a chart setting forth the variables for programming the computer chip used in the liquid flow meter. 
     
    
     DETAILED DESCRIPTION  
       [0024]    Accordingly, as depicted in FIGS. 1 and 2, an odor trap  20 , such as disclosed in above-mentioned U.S. Pat. No. 6,053,197 and U.S. patent application, Ser. No. 09/855,735, comprises a cylindrical housing  22 , a bottom portion  24  and a cover or top portion  26 , which define an interior  27 . Internally, odor trap  20  includes a vertical baffle  28  secured to and extending downwardly from cover  26 , a sloped, generally horizontal baffle  30  secured to vertical baffle  28  and an overflow riser  32  extending upwardly from bottom portion  24 . Overflow riser  32  comprises a walled section to form a discharge path from interior  27  of trap  20  through an exit  34  which is coupled to an external drain system. An entry  36  forms an opening into interior  27 .  
         [0025]    The interior is adapted to retain a conductive liquid  38 , e.g., wastewater such as a mixture of water and urine, on which a sealant layer  40  of oily substance floats. Accordingly, the wastewater enters odor trap  20  through one or more openings  36 , flows into and passes through sealant layer  40 , and flows atop and beneath baffle  30  on its journey over overflow riser  32  and out of the odor trap through exit  34 .  
         [0026]    Cover  26  is further provided with a centrally positioned opening  42 , surrounded by entry  36 .  
         [0027]    As illustrated generally in FIGS.  3 - 5  and in greater detail in FIGS.  7 - 15 , a liquid flow meter  50  is adapted to be secured to odor trap  20  at cover opening  42 . Specifically, meter  50  is provided with connector  52  comprising a post  54  terminating in a pair of tangs  56  bulbous bosses  58 . Cover opening  42  and post  54  have approximately equal diameters to permit bosses  58  to pressed tangs  56  together as they pass through the cover opening and thence to snap outwardly to latch the liquid flow meter to odor trap  20 .  
         [0028]    The electric circuit embodied in liquid flow meter  50  is shown in FIG. 6. The driving mechanism of the meter is embodied in a microcontroller  60 , such as a 12LC508A-04/SN microcontroller, which is one of a PICD12C5XX family of microcontrollers from Microchip Technology. The PICD12C5XX is defined as a family of low-cost, high performance, 8-bit, fully static, EEPROM/EPROM/ROM based CMOS microcontrollers. It employs a RISC architecture with 33 single word/single cycle instructions. All instructions are single style (1 μs) except for program branches which take two cycles. The PICD12C5XX includes 12-bit wide instructions which are highly symmetrical, resulting in 2:1 code compression.  
         [0029]    Microcontroller  60  is provided with eight input and output pins (numbers  1 - 8 ) in which pins “6” and “7” are coupled to a pair of contact sensor probes  62  and  64  at their respective contact points  62   x  and  64   x  respectively by leads  62 ′ and  64 ′. Pin “5” is coupled through a resistor  66  to a LED  68  through the intermediary of leads  67 , and pin “1” is coupled to a source of power “VCC”  70 , such as a 3.3 volt lithium battery, e.g., CR1220. The couplings to the positive side of battery  70  is through a connection device having three termini, respectively designated battery clip (positive)  70  and  70   a′, a″, a′″  (see FIGS.  7 - 14 ). The couplings to the negative side of battery  70  is through a connection device having two termini, respectively designated battery clip (negative)  70  and  70   b′, b″  (also see FIGS.  7 - 14 ). These termini act both as clips and as electric connections aided, for example, by soldering. LED  68  is coupled to power source  70 . Pin “8” is grounded, as designated by indicium  76 . Functioning of the microprocessor and its circuit are described below.  
         [0030]    The various connections among the several electric components including microcontroller  60 , sensor probes  62  and  64 , resistor  66 , positive and negative battery clips  70   a  and  70   b  are enabled by a circuit board  78 . Where needed, insulation is provided, such as by a clip insulator  80 .  
         [0031]    As best shown in FIGS.  2 - 5 , sensor probes  62  and  64  are positioned in liquid flow meter  50  so that their exposed termini  63  do not extend to the bottom surface (designated by indicium  65 ) of the meter and, therefore, are spaced from cover  26 . This spacing of termini  63  avoids undesired closure between the probes, should, for example, the level of the liquids in odor trap  20  rise during use through entry  36  in cover  26 . Further, the spacing between termini  62   c  and  64   b  and between termini  62   b  and  64   c,  in particular, is limited to a minimum distance to avoid unintentional contact therebetween, for example, of droplets of wastewater that have not passed through entry  36 .  
         [0032]    Reference is now made to FIGS. 16 and 17. FIG. 16 illustrates the flow of logic used in sensing and measuring the activities occurring in odor trap  20 . The glossary of terms used in the following is:  
         [0033]    “Uses”—A use is when the sensor contacts detect the presence of a fluid, within a specified period of time.  
         [0034]    “Use Counter” or “Counter #1”—Counts the total number of uses  
         [0035]    “Use Timer” or “Timer #1”—A Use Timer determines the period of time between initial fluid contact and when the next fluid contact can be recorded.  
         [0036]    “Blockage”—A blockage is when fluid is detected by the sensor contacts continuously for a specified amount of time.  
         [0037]    “Blockage Timer” or “Timer #2”—Blockage Timer records records the duration of continuous fluid presence by the sensor contacts.  
         [0038]    “Blockage Counter” or “Counter #2”—Blockage Counter records the number of blockages as determined by Blockage Timer, when the timer exceeds a specific minimum amount of time.  
         [0039]    Further, in the following exposition of the algorithm, the term “X” indicates time which is a programmable variable, to which reference is directed to FIG. 17. Operation is assumed that meter  50  is in an inactive “turned-off” condition. Operation commences, as shown in enclosure  100 , when urine flow contacts sensors on indicator or meter to activate the system. As shown in enclosure  102 , counter #1 in microprocessor  60  records one use. Counter #1 will not record another use for “X1” amount of time or if probes  62  and  64  are submerged. If, as depicted in enclosure  104 , the urine maintains contact between the probes for a time longer than an “X3” period of time, counter #2 records one blockage. In the next step, as outlined in enclosure  106 , if blockage occurs “X4” number of times consecutively, LED  68  flashes to indicate a blockage. As shown in enclosure  108 , flashing continues until power is exhausted or reset is activated. However, as pointed out in enclosure  112 , if blockage does not occur for “X4” number of times consecutively, counter #2 resets to 0.  
         [0040]    Alternatively, as stated in enclosure  110 , when the number of uses reaches “X5”, the end of the lifecycle of flashing LED  68  is activated for “X6” of a second and “X7” times a minute, and the program proceeds directly to the step outlined in enclosure  108 , that is, flashing continues until power is exhausted or reset is activated.  
         [0041]    The next step proceeds to that embraced in enclosure  114 , if the reset feature is active in progress, that is, if the sensor contacts are closed “X8” number of times within 4 seconds, the indicator/meter  60  will proceed to a warning state. If the sensor contacts are closed “X8” number of times within 4 seconds again, the indicator will reset. Finally, as circumscribed in enclosure  116 , if reset is activated, all counters are reset to 0.  
         [0042]    Optionally, as set forth in enclosure  118 , LED  68  will single flash for “X2” time per use.  
         [0043]    Several materials may be used in the present invention. The cover shell may be made of any number of thermoplastic materials such as ABS or polypropylene plastic. The electronics are held in place in the mold by the location of the LED and the sensor contact points. Although injection molding is one method of encapsulation, other methods could be used successfully, such as potting and cold injection.  
         [0044]    The present invention is installed by placing the split ball stem (connector  52 , post  54 , post  56 , pair of tangs  56 , bosses  58 ) located at the base of the indicator into mounting hole  42  located in the center of drain holes  36  on the top or cover of the cartridge.  
         [0045]    The present invention operates in three states:  
         [0046]    1. Packaged: Preinstalled into the lid of the cartridge, the indicator is active but in a sleep mode.  
         [0047]    2. Installed: Indicator and cartridge is installed in a urinal and ready for first urine contact. No information is stored save for the ROM programming.  
         [0048]    3. Initial Fluid Detection: The high mineral content of the urine (or water, which has a lesser mineral content) will complete the circuit between the sensor probes, powering the chip and allowing information to be stored.  
         [0049]    In one embodiment, the algorithm of the Fluid Detection state, as noted above, is as follows:  
         [0050]    1. Upon each detection of fluid, “Use Counter” will increment by (1), and “Use Timer” records Duration of fluid detection. The “Use Counter” will not record another use for a short, predetermined amount of time (e.g., 50 seconds) to avoid falsely recording two uses, when only one use should be recorded or as long as the fluid is still present).  
         [0051]    2. If number of uses (Use Counter) is greater than the predetermined number (in one embodiment, 7000), the unit activates Change Signal (continuous or flashing LED).  
         [0052]    3. If the Time Duration of fluid detection is greater than the predetermined value (in one embodiment, 75 seconds), Blockage Counter increments by (1).  
         [0053]    4. If Blockage Counter equals the predetermined number (in one embodiment, 3) and these events are consecutive, unit activates Change Signal (FLASH).  
         [0054]    5. If the predetermined number of Blockage Events is not consecutive then the Blockage Counter will reset to zero.  
         [0055]    In an alternative embodiment, a reset feature is provided:  
         [0056]    1. If time duration of flow is less than one second, very short predetermined value (in one embodiment, 0.5 seconds), clicks the Reset Counter once, and tracks Reset Time.  
         [0057]    2. If the Reset Counter equals a predetermined value (in one embodiment, 10) and the Reset Time is less than or equal to a predetermined value (in one embodiment, 5 seconds), all counters are reset to zero.  
         [0058]    3. If Reset Time is greater than a predetermined value (in one embodiment, 5 seconds) resets Reset Counter and Reset Time to zero.  
         [0059]    In a related alternative embodiment, a feature is provided to signal if the urinal is blocked: If time duration of flow is greater than a very long predetermined value (in one embodiment, 75 seconds, for example), the unit activates Change Signal.  
         [0060]    In an alternative embodiment, the present invention will give a Change Signal triggered by a total time in service.  
         [0061]    1. Upon Initial Fluid Detection, Powers Chip and initiates Duration Clock.  
         [0062]    2. When Duration Clock reaches a predetermined number of days (in one embodiment, 90 days) activates Change Signal.  
         [0063]    In another alternative embodiment, the present intention will flash an LED every time it is in use:  
         [0064]    1. Upon Fluid Detection, activates In-Use Flash Signal ({fraction (1/10)} second) to indicate the device is working. In-Use Flash Signal feature resets upon end of Fluid Detection.  
         [0065]    In the another alterative embodiment, the present invention uses a second LED to provide an in-use signal, and the first LED for overfill. The two LED&#39;s may employ different colors. Further, different colors and different LED&#39;s may be used for different signals.  
         [0066]    The device can be employed in a flush urinal, by connecting it to a solenoid valve that cuts off the flow of flush water in the event of blockage. The connection may be by hard wire or transmitter and receiver.  
         [0067]    Although water has a lower mineral content and will work, a properly adjusted sensor is needed to determine the difference between water and urine. Thus, in an alternative embodiment, the resistance limit is set so that water, which may be used to flush out the system, is not recognized, but urine is.  
         [0068]    Although the invention has been described with respect to a particular embodiment thereof, it should be realized that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

Summary:
A liquid flow meter ( 50 ), including a microcontroller ( 60 ) and associated algorithm, monitors urine flow through a cartridge trap ( 20 ). Measuring the duration of such flow and the number of times the urinal is used will determine, in accordance with preset criteria, when servicing or replacement is needed, and alerts a service person to that effect by a warning light ( 68 ) or other signal. Because urine has a high mineral content, it is electrically conductive, effective to complete circuits between closely spaced metal contacts ( 62   a - 62   c,    64   a - 64   c ) coupled to the PROM, which allows the manner and existence of the urine to be detected. The liquid flow meter is installed in the cartridge trap by utilizing and placing a split ball stem ( 52 ) located at the base of the meter into a mounting hole ( 42 ) located in the center of the drain holes ( 36 ) on the cartridge cover ( 26 ).