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
(62a-62c, 64a-64c) 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
What is claimed is:
1. An electric circuit for monitoring the flow of at least one
electrically conductive liquid through a trap in a urinal to determine
when the trap needs to be changed or serviced, comprising: a microcontroller
for sensing the presence and duration of the presence of the conductive
liquid and for directing actions established by preset criteria;
at least one pair of contact sensor probes coupled to said microcontroller
and disposed to be electrically connected together by the electrically
conductive liquid; and an indicator coupled to said microcontroller
for indicating the actions directed thereby.
2. An electric circuit according to claim 1 in which said microcontroller
comprises an 8-bit, fully static, EEPROM/EPROM/ROM based CMOS microcontroller.
3. An electric circuit according to claim 1 in which said microcontroller
records the number of liquid flows and if the number exceeds a second
predetermined number appropriately activates said indicator.
4. An electric circuit according to claim 1 in which: said microcontroller,
said contact sensor probes and said indicator are housed in a liquid
flow meter enclosure; said trap includes an entry and an exit for
respectively receiving and discharging the liquid and structure
at said entry for receiving said liquid flow meter; and said contact
sensor probes are spaced from said entry structure for avoiding
undesired electric closure between the probes by the conductive
5. An electric circuit according to claim 4 in which said liquid
flow meter enclosure includes a latching mechanism latchingly engageable
with said entry.
6. An electric circuit according to claim 1 in which said microcontroller
is programmed to sense flow of the conductive liquid by said probes,
to sense the length of time of the liquid contact and compare it
to a predetermined length of time and if the time of liquid contact
exceeds said predetermined length of time, to record a blocked condition,
and to appropriately activate said indicator if the number of blocked
conditions exceeds a predetermined number.
7. An electric circuit according to claim 6 in which said indicator
is activated if the preset number of blocked conditions occur without
intervening liquid contact of a duration that does not exceed said
predetermined length of time.
8. An electric circuit according to claim 1 in which said microcontroller
is programmed to sense flow of the conductive liquid by said probes,
to activate said microcontroller when the conductive fluid is sensed,
to record the number of sensed flows with respect to liquid contact
of the probes, to count the length of time of the liquid contact
that may evidence a blockage, to appropriately activate said indicator
in response to the blockage, and to reset said microcontroller if
blockage does not occur a preset number of times consecutively.
9. In a urinal having a removable trap having a urine flow path,
a method for determining when the trap requires changing and servicing
by use of a microcontroller and a designator for respective effecting
of the changing and servicing, comprising the steps of: sensing
flow of the urine; activating the microcontroller when the urine
is sensed; recording the number of sensed flows with respect to
contact with the urine; sensing the length of time of the urine
contact and any blockage and times of blockage produced thereby;
appropriately activating the designator in response to the blockage
sensing; and resetting the microcontroller should blockage not occur
a preset number of times consecutively.
10. A method according to claim 9 in which: said step of sensing
flow of the urine comprises the step of utilizing contacts positioned
in a path of the urine flow, and activating the microcontroller
when urine is sensed; said recording step comprises the steps of
counting a first sensing and not recording another sensing for a
preset amount of time or if the contacts are submerged in the urine;
said step of sensing the length of time of the urine contact and
any blockage and times of blockage produced thereby comprises the
steps of determining if the urine maintains contact longer than
a preset length of time, and recording the longer period of time
as a blockage incident; and said appropriate designator activation
step comprises the steps of detecting a preset n umber of consecutive
times that the blockage occurs, when the number of sensing reaches
a preset number, activating the designator for a preset length of
time and for a preset number of times per unit of time, and continuing
said detector activating step until power is exhausted or a reset
11. A method according to claim 9 in which said resetting step
further comprises the steps of: placing the designator in a warning
condition if sensor contacts are repeatedly closed a preset number
of times within a preset length of time; and resetting the time
of said counting steps to zero if blockage does not consecutively
occur a present number of times.
REFERENCE REGARDING FEDERAL SPONSORSHIP
REFERENCE TO MICROFICHE APPENDIX
1. Field of the Invention
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.
2. Description of Related Art and Other Considerations
Waterless urinals, such as are disclosed in U.S. Pat. No. 6053197
and U.S. Pat. No. 6425411 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
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.
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
FIG. 1 is a perspective view of the present invention depicting
a removable trap utilized in a urinal with a liquid flow meter installed
FIG. 2 is a cross-sectional view of the present invention illustrated
in FIG. 1;
FIG. 3 is a perspective view of the liquid flow meter taken from
its exterior or cover;
FIGS. 4 and 5 are side views of the exterior or cover of the liquid
flow meter, with one taken 90.degree. from the other;
FIG. 6 is an electric schematic diagram of the of the liquid flow
FIG. 7 is an exploded perspective view of the present invention;
FIG. 8 is a perspective view of the liquid flow meter depicted
in FIG. 3 with its outer cover removed to disclose the interior
FIG. 9 is a top view of the liquid flow meter;
FIG. 10 is a bottom, upwardly looking view of the liquid flow meter,
taken 90.degree. from that depicted in FIG. 9;
FIGS. 11 and 12 are side views of the liquid flow meter, with one
view being taken 90.degree. from the other;
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;
FIG. 15 is a perspective view of the sensor contact clips employed
in the liquid flow meter illustrated in FIGS. 8-12;
FIG. 16 is a logic flow chart depicting the algorithm utilized
in operating the liquid flow meter of the present invention; and
FIG. 17 is a chart setting forth the variables for programming
the computer chip used in the liquid flow meter.
Accordingly, as depicted in FIGS. 1 and 2 an odor trap 20 such
as disclosed in above-mentioned U.S. Pat. No. 6053197 and U.S.
patent application, Ser. No. 09/855735 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
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
Cover 26 is further provided with a centrally positioned opening
42 surrounded by entry 36.
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 with 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.
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 .mu.s) 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.
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 62x and 64x respectively by leads 62' and 64'. Pin
"5" is coupled through a resistor 68 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 70a', a", a'"
(see FIGS. 7-14). The couplings to the negative side of battery
70 are through a connection device having two termini, respectively
designated battery clip (negative) 70 and 70b', 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
The various connections among the several electric components including
microcontroller 60 sensor probes 62 and 64 resistor 66 positive
and negative battery clips 70a and 70b are enabled by a circuit
board 78. Where needed, insulation is provided, such as by a clip
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
62c and 64b and between termini 62b and 64c, in particular, is limited
to a minimum distance to avoid unintentional contact therebetween,
for example, of droplets of wastewater that have not passed through
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:
"Uses"--A use is when the sensor contacts detect the
presence of a fluid, within a specified period of time.
"Use Counter" or "Counter #1"--Counts the total
number of uses
"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.
"Blockage"--A blockage is when fluid is detected by the
sensor contacts continuously for a specified amount of time.
"Blockage Timer" or "Timer #2"--Blockage Timer
records records the duration of continuous fluid presence by the
"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.
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.
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.
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.
Optionally, as set forth in enclosure 118 LED 68 will single flash
for "X2" time per use.
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.
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.
The present invention operates in three states:
1. Packaged: Preinstalled into the lid of the cartridge, the indicator
is active but in a sleep mode.
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.
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.
In one embodiment, the algorithm of the Fluid Detection state,
as noted above, is as follows:
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.
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).
3. If the Time Duration of fluid detection is greater than the
predetermined value (in one embodiment, 75 seconds), Blockage Counter
increments by (1).
4. If Blockage Counter equals the predetermined number (in one
embodiment, 3) and these events are consecutive, unit activates
Change Signal (FLASH).
5. If the predetermined number of Blockage Events is not consecutive
then the Blockage Counter will reset to zero.
In an alternative embodiment, a reset feature is provided:
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.
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
3. If Reset Time is greater than a predetermined value (in one
embodiment, 5 seconds) resets Reset Counter and Reset Time to zero.
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.
In an alternative embodiment, the present invention will give a
Change Signal triggered by a total time in service.
1. Upon Initial Fluid Detection, Powers Chip and initiates Duration
2. When Duration Clock reaches a predetermined number of days (in
one embodiment, 90 days) activates Change Signal.
In another alternative embodiment, the present intention will flash
an LED every time it is in use:
1. Upon Fluid Detection, activates In-Use Flash Signal (1/10 second)
to indicate the device is working. In-Use Flash Signal feature resets
upon end of Fluid Detection.
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's may employ different colors. Further, different
colors and different LED's may be used for different signals.
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
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.
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.