U.S. patent application number 15/697780 was filed with the patent office on 2019-03-07 for chemical product dispenser with washing machine tank fill level detection.
The applicant listed for this patent is Delaware Capital Formation, Inc.. Invention is credited to Terry Tincher.
Application Number | 20190069755 15/697780 |
Document ID | / |
Family ID | 63144840 |
Filed Date | 2019-03-07 |
United States Patent
Application |
20190069755 |
Kind Code |
A1 |
Tincher; Terry |
March 7, 2019 |
CHEMICAL PRODUCT DISPENSER WITH WASHING MACHINE TANK FILL LEVEL
DETECTION
Abstract
Systems, methods, and software program products for dispensing
chemical products to a washing machine. A dispenser receives a
conductivity signal from a conductivity circuit having input
terminals coupled to a probe in a tank of the washing machine. The
dispenser may compare the conductivity signal to a threshold
indicative of a low level of conductivity between input terminals
of the conductivity circuit. In response to the conductivity signal
breaching the threshold, the dispenser may determine the tank of
the washing machine is being drained of a washing solution. In
response to the conductivity signal subsequently breaching another
threshold indicative of a high level of conductivity between the
input terminals, the dispenser may determine the tank is being
filled, and dispense a predetermined amount of the chemical product
into the tank.
Inventors: |
Tincher; Terry; (Lebanon,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Delaware Capital Formation, Inc. |
Wilmington |
DE |
US |
|
|
Family ID: |
63144840 |
Appl. No.: |
15/697780 |
Filed: |
September 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47L 15/0076 20130101;
A47L 15/4297 20130101; D06F 39/087 20130101; D06F 39/022 20130101;
A47L 2401/30 20130101; D06F 33/37 20200201; D06F 2204/02 20130101;
A47L 2401/023 20130101; A47L 2501/07 20130101; D06F 2202/02
20130101; D06F 2103/18 20200201; A47L 15/0028 20130101; D06F 33/00
20130101; A47L 15/4418 20130101; D06F 2210/00 20130101; A47L 15/449
20130101; D06F 2105/42 20200201; D06F 34/22 20200201; A47L 15/0021
20130101; A47L 2401/09 20130101 |
International
Class: |
A47L 15/44 20060101
A47L015/44 |
Claims
1. A dispenser for dispensing a chemical product to a washing
machine, the dispenser comprising: a processor; and a memory
coupled to the processor and containing program code that, when
executed by the processor, causes the dispenser to: receive a
conductivity signal from a conductivity circuit; compare the
conductivity signal to a first threshold; and in response to the
conductivity signal breaching the first threshold, determine a tank
of the washing machine is being drained of a washing solution.
2. The dispenser of claim 1 wherein the program code further causes
the dispenser to: in response to determining the conductivity
signal breached the first threshold, compare the conductivity
signal to a second threshold; and in response to the conductivity
signal breaching the second threshold, determine the tank of the
washing machine is being filled with the washing solution.
3. The dispenser of claim 2 wherein the program code further causes
the dispenser to: in response to determining the tank is being
filled with the washing solution, dispense a predetermined amount
of chemical product into the tank.
4. The dispenser of claim 3 wherein the predetermined amount of
chemical product is determined based on a capacity of the tank and
a desired concentration of the chemical product in the washing
solution.
5. The dispenser of claim 1 wherein the program code further causes
the dispenser to: in response to the conductivity signal breaching
the first threshold, dispense a first predetermined amount of
chemical product into the tank; and in response to the conductivity
signal not breaching the first threshold and receiving a status
signal from the washing machine indicating the washing machine is
starting a wash cycle, dispense a second predetermined amount of
the chemical product into the tank.
6. The method of claim 5 wherein the second predetermined amount of
chemical product is less than the first predetermined amount of
chemical product.
7. The dispenser of claim 1 wherein the conductivity circuit has an
output on which the conductivity signal is provided, and an input
coupled to a probe located in the tank.
8. The dispenser of claim 7 wherein the probe is a conductivity
probe.
9. The dispenser of claim 7 wherein the probe is a float probe.
10. The dispenser of claim 9 wherein the probe includes: a float
having a magnet; and a magnetic switch, and the probe is configured
so that the magnet causes the magnetic switch to be in a closed
state when the tank is full, and in an open state when the tank is
empty.
11. A method of dispensing a chemical product to a washing machine,
the method comprising: receiving a conductivity signal from a
conductivity circuit; comparing the conductivity signal to a first
threshold; and in response to the conductivity signal breaching the
first threshold, determining a tank of the washing machine is being
drained of a washing solution.
12. The method of claim 11 further comprising: in response to
determining the conductivity signal breached the first threshold,
comparing the conductivity signal to a second threshold; and in
response to the conductivity signal breaching the second threshold,
determining the tank of the washing machine is being filled with
the washing solution.
13. The method of claim 12 further comprising: in response to
determining the tank is being filled with the washing solution,
dispensing a predetermined amount of chemical product into the
tank.
14. The method of claim 13 wherein the predetermined amount of
chemical product is determined based on a capacity of the tank and
a desired concentration of the chemical product in the washing
solution.
15. The method of claim 11 further comprising: in response to the
conductivity signal breaching the first threshold, dispensing a
first predetermined amount of chemical product into the tank; and
in response to the conductivity signal not breaching the first
threshold and receiving a status signal from the washing machine
indicating the washing machine is starting a wash cycle, dispensing
a second predetermined amount of the chemical product into the
tank.
16. The method of claim 11 wherein the conductivity circuit has an
output on which the conductivity signal is provided, and an input
coupled to a probe located in the tank.
17. The method of claim 16 wherein the probe is a conductivity
probe.
18. The method of claim 16 wherein the probe is a float probe.
19. The method of claim 18 wherein the probe includes: a float
having a magnet; and a magnetic switch, and the probe is configured
so that the magnet causes the magnetic switch to be in a closed
state when the tank is full, and in an open state when the tank is
empty.
20. A computer program product for dispensing a chemical product to
a washing machine, the computer program product comprising: a
non-transitory computer-readable storage medium; and program code
stored on the non-transitory computer-readable storage medium that,
when executed by one or more processors, causes the one or more
processors to: receive a conductivity signal from a conductivity
circuit; compare the conductivity signal to a first threshold; and
in response to the conductivity signal breaching the first
threshold, determine a tank of the washing machine is been drained
of a washing solution.
Description
BACKGROUND
[0001] The invention generally relates to washing machines, and in
particular, to systems, methods, and software products for
dispensing chemicals to a commercial washing machine.
[0002] There are various types of commercial washing machines. Two
of the most common types of ware washing machines are batch-type
machines and conveyor-type machines. Batch-type machines include a
chamber configured to receive one or more racks of dishes. The
racks to be washed are placed in the chamber, and each step of the
washing process (e.g., scraping, washing, rinsing, and/or
sanitizing) is performed sequentially while the racks are in the
chamber. When the washing process is complete, the racks of clean
dishes are removed, and new racks of dirty dishes placed in the
chamber. In a conveyor-type machine, racks of dishes are loaded one
at a time onto a conveyor that carries the racks through multiple
stations (e.g., scraping, washing, rinsing, and/or sanitizing
stations) within the machine. Each station includes a chamber
through which the racks of dishes pass as they are conveyed through
the machine, with each chamber performing a step of the washing
process. Each rack of dishes is thereby exposed to each step of the
washing process sequentially as it moves through the machine, and
is removed as the rack emerges from the final station.
[0003] Whether the washing machine comprises a single chamber or a
plurality of chambers, each chamber will typically include a tank
containing a solution that is used to perform one of the steps of
the washing process, such as a solution of water and a detergent,
rinse aid, and/or sanitizer. For each step to be effective, the
level of chemical product in the respective solution must be
maintained within a specified range. Thus, controlled amounts of
the chemical product must be added when the reservoir is drained
and refilled. As dishes are processed, additional amounts of
chemical product may also be added to replace product that is
consumed and/or diluted by the processing step.
[0004] One problem that must be addressed when using an external
dispenser is determining when the tank has been drained and
refilled with fresh water. When new water is introduced into the
dishwasher, the dispenser needs to provide an initial charge that
produces a concentration of the product at or above the minimum
required level. Typically, the initial charge is much larger than
the charges added between cycles to maintain concentration levels
when the tank is not being drained and refilled. Conventional
dispensing systems attempt to control the concentration of chemical
product by monitoring the conductivity of the solution in the tank,
and adding chemical product to the tank as needed to maintain the
conductivity of the solution at a level set by the user. However,
this method has some shortcomings.
[0005] For example, the solution in the tank often contains varying
levels of contaminants that affect the conductivity of the
solution. This can cause the dispenser to dispense incorrect
amounts of chemical product, and allow the concentration of
chemical product to fall below the minimum level. There is also
normally a large time lag between when the chemical product is
dispensed and when a corresponding change in conductivity of the
solution is detected, which may result in the dispenser dispensing
too much chemical product. In addition, as the electrodes of the
conductivity probe age, they may become corroded or coated with
non-conductive residue that affects the accuracy of the measured
conductivity, and thus the amount of chemical product dispensed.
Still further, because the conductivity level must be set by the
user and can vary depending on the type of probe and chemical
product being used, there is a high likelihood that the level will
be set incorrectly.
[0006] Therefore, there is a need for improved systems, methods,
and software products for dispensing chemical products to washing
machines.
SUMMARY
[0007] In an embodiment of the invention, a dispenser for
dispensing a chemical product to a washing machine is provided. The
dispenser includes a processor and a memory coupled to the
processor. The memory contains program code that, when executed by
the processor, causes the dispenser to receive a conductivity
signal from a conductivity circuit, and compare the conductivity
signal to a threshold. In response to the conductivity signal
breaching the threshold, the program code further causes the
dispenser to determine a tank of the washing machine is being
drained of a washing solution.
[0008] In another embodiment of the invention, a method of
dispensing the chemical product to the washing machine is provided.
The method includes receiving the conductivity signal from the
conductivity circuit, comparing the conductivity signal to the
threshold, and in response to the conductivity signal breaching the
threshold, determining the tank of the washing machine is being
drained of the washing solution.
[0009] In another embodiment of the invention, a computer program
product for dispensing the chemical product to the washing machine
is provided. The computer program product includes a non-transitory
computer-readable storage medium, and program code stored on the
non-transitory computer-readable storage medium. The program code
is configured to, when executed by one or more processors, cause
the one or more processors to receive the conductivity signal from
the conductivity circuit, compare the conductivity signal to the
threshold, and in response to the conductivity signal breaching the
threshold, determine the tank of the washing machine is being
drained of the washing solution.
[0010] The above summary may present a simplified overview of some
embodiments of the invention to provide a basic understanding of
certain aspects the invention discussed herein. The summary is not
intended to provide an extensive overview of the invention, nor is
it intended to identify any key or critical elements, or delineate
the scope of the invention. The sole purpose of the summary is
merely to present some concepts in a simplified form as an
introduction to the detailed description presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate various
embodiments of the invention and, together with the general
description of the invention given above, and the detailed
description of the embodiments given below, serve to explain the
embodiments of the invention.
[0012] FIG. 1 is a diagrammatic view of an operating environment
including a washing machine and a dispensing system.
[0013] FIG. 2 is a diagrammatic view of a probe for use in the
washing machine of FIG. 1.
[0014] FIG. 3 is a diagrammatic view of another probe for use in
the washing machine of FIG. 1.
[0015] FIG. 4 is a diagrammatic view of a controller of the
dispensing system of FIG. 1.
DETAILED DESCRIPTION
[0016] FIG. 1 depicts an exemplary operating environment that
includes a washing machine 10 (e.g., a dishwasher) and a dispensing
system 12 in accordance with an embodiment of the invention.
Although the exemplary washing machine 10 is illustrated as a
batch-type dishwasher, the dispensing system 12 may also be used
with other types of machines, such as conveyor-type dishwashers or
laundry machines. Thus, embodiments of the invention are not
limited to the type of washing machine depicted.
[0017] The washing machine 10 may include a chamber 14 that is
accessed through a water-tight door 16, a pump 18 having an input
port 20 and an output port 22, one or more valves 24, 26, a
controller 28, and rails 30 configured to receive a rack 32. The
controller 28 may include a processor and a memory storing program
code that, when executed by the processor, causes the controller 28
to execute one or more processes used to operate the washing
machine 10.
[0018] A bottom portion of the chamber 14 may define a tank 34
having a capacity and configured to hold a washing solution 36. The
tank 34 may include a sump 38 having an opening 40 at the bottom
thereof that is coupled to the input port 20 of pump 18. The valve
24 may selectively couple the output port 22 of pump 18 to a
manifold 42 or a drain 44 in response to signals received from the
controller 28. The manifold 42 may be coupled to upper and lower
spray arms 46, and may be selectively coupled by valve 26 to a
water source 48 in response to signals from the controller 28. The
spray arms 46 may be configured to direct washing and/or rinsing
solutions provided under pressure to the manifold 42 onto wares 50
in rack 32. The water source 48 may be configured to provide water
to the washing machine 10 at a temperature suitable for washing
and/or sterilizing the wares 50. The washing machine 10 may also
include one or more heating elements and/or temperature probes (not
shown) that enable the controller 28 to control the temperature of
the washing solution 36.
[0019] The dispensing system 12 may include a dispenser 52 having
one or more (e.g., two) pumps 54, 56, a controller 58, and a
conductivity circuit 59. The dispenser 52 may be in communication
with, and/or receive power from, the controller 28 of washing
machine 10 over a cable 61. The controller 58 may also be in
communication with a probe 63 configured to generate a signal
indicative of the conductivity, presence, and/or absence of washing
solution 36 in tank 34. Each pump 54, 56 may include an input port
60, 62 and an output port 64, 66. Each input port 60, 62 may be
coupled to a respective reservoir 68, 70 of chemical product, such
as a detergent, rinse aid, or sanitizer used by the washing machine
10.
[0020] The output port 64 of pump 54 may be coupled to a bulkhead
fitting 72 of chamber 14 by a supply line 74. The bulkhead fitting
72 may be located above a fill line 76 of tank 34, and may be used
to fill the tank 34 with washing solution 36. To this end, a valve
78 may be configured to selectively couple the supply line 74 to
the water source 48 in response to signals received from the
controller 58. Water flowing from the valve 78 to the supply line
74 may be provided with detergent by activating the pump 54 to
inject detergent into the supply line 74, and/or by passing the
water through a Detergent Capsule Feeder (DCF) 80. The probe 63 may
be located proximate to the bulkhead fitting 72 and below the fill
line 76 so that when the tank 34 is full, the probe 63 is at least
partially submerged in washing solution 36. The probe 63 may be,
for example, a conductivity probe configured to detect a
conductivity of the washing solution 36 and/or float probe
configured to detect a level of the washing solution 36.
[0021] An injection fitting 82 may couple the output port 66 of
pump 56 to the manifold 42. The dispenser 52 may provide another
chemical product (e.g., a rinse aid and/or sanitizer) to the
washing machine 10 by activating the pump 56 while the valve 26 is
in an open state. This may cause the chemical product to be
injected into the manifold 42, where it may mix with water flowing
through the manifold 42 and be carried into the washing machine
10.
[0022] Referring now to FIG. 2, in an embodiment of the invention
in which the probe 63 is a conductivity probe 63a, the probe 63a
may include a body 84 having a threaded barrel 86, a shoulder 88, a
head 90, and one or more electrodes 92, 94 each passing through the
body 84 in a generally parallel arrangement. Each electrode 92, 94
may include a distal end 96, 98 that projects outward
longitudinally from the threaded barrel 86 to contact the washing
solution 36, and a proximal end 100, 102 that projects outward
longitudinally from the head 90 to provide a point of connection to
the probe 63a. The head 90 may be configured to receive a tool,
such as an open-end wrench, to facilitate installation of the probe
63a in the washing machine 10. The threaded barrel 86 may be
configured to pass through an aperture (not shown) in a wall 106 of
tank 34, and receive a threaded ring 108 that secures the probe 63a
to the wall 106.
[0023] An outer gasket 110 may be located between a wall facing
surface 112 of shoulder 88 and an outer surface 113 of wall 106,
and an inner gasket 116 may be located between a wall facing
surface 114 of the threaded ring 108 and an inner surface 115 of
wall 106. Rotating the threaded ring 108 relative to the threaded
barrel 86 may cause the outer and inner gaskets 110, 116 to be
compressed between the respective surfaces 112-115 to form a
fluid-tight seal between the probe 63a and the wall 106 of tank
34.
[0024] Referring now to FIG. 3, in an embodiment of the invention
in which the probe 63 is a float probe 63b, the probe 63b may
include a float 120, a body 122 having an angled portion 124, a
shoulder 126, a threaded barrel 127, and a pair of conductors 128,
129. The angled portion 124 of body 122 may include a threaded
opening configured to receive a shaft 130. The shaft 130 may
include a threaded proximal end 132 configured to engage the
threaded opening of angled portion 124, a flange 134 proximate to
the proximal end 132, and a distal end 136 including a retainer 138
having a plurality of flexible tines 140. Each of the flexible
tines 140 of retainer 138 may project outward from the distal end
136 of shaft 130 at an acute angle to an axis of the shaft 130 so
that the tines 140 are angled toward the proximal end 132 of shaft
130.
[0025] The float 120 may have a density such that it is buoyant in
the washing solution 36, and may include a magnet and a passage
(not shown). The passage may include a proximal end and a distal
end, and may be configured to receive the shaft 130. When the
retainer 138 is inserted into the proximal end of the passage, a
surface of the passage may deflect the tines 140 inward toward the
shaft 130. This deflection may allow the float 120 to move onto the
shaft 130. Upon emerging from the distal end of the passage, the
tines 140 may spring back into their relaxed positions, thereby
preventing the float 120 from sliding off the distal end 136 of
shaft 130.
[0026] The float 120 may move along the shaft 130 over a range
defined by a position at which the float 120 contacts the retainer
138 at the distal end 136 of shaft 130, and the position at which
the float 120 contacts the flange 134 at the proximal end of shaft
130. The probe 63b may be configured to provide one impedance
between the conductors 128, 129 (e.g., a low impedance
characteristic of a closed switch) when the float 120 is at one end
of its range of movement along the shaft 130, and another impedance
(e.g., a high impedance characteristic of an open switch) when the
float 120 is at the other end of its range of movement along the
shaft 130.
[0027] For example, in an embodiment of the invention, the probe
63b may include a magnetic switch (e.g., a Reed switch) having an
electrical characteristic (e.g., an impedance) that is altered by
the presence of a magnetic field. The magnetic switch may be
located in the probe 63b so that when the float 120 is in one
position (e.g., near the proximal end 132 of shaft 130), the magnet
in the float 120 causes the magnetic switch to have one
characteristic (e.g., an impedance indicative of a closed state),
and when the float 120 is in another position (e.g., near the
distal end 136 of shaft 130), the magnet in the float causes the
magnetic switch to have another characteristic (e.g., a high
impedance indicative of an open state). The controller 58 of
dispensing system 12 may thereby determine if the washing solution
36 is above or below a predetermined level based on the impedance
between the conductors 128, 129 of probe 63b.
[0028] The probe 63b may be secured to the wall 106 of tank 34 in a
position where the float 120 is sufficiently immersed in the
washing solution 36 when the tank 34 is full so as to cause a
switch (e.g., a mechanical switch, a mercury switch, or the
magnetic switch) to be in the closed state. The probe 63b may be
further positioned so that it is exposed to a flow of washing
solution 36 proximate to the bulkhead fitting 72. The threaded
barrel 127 of body 122 may be configured to pass through the
aperture in the wall 106 of tank 34, and receive a threaded ring
142 that secures the probe 63b to the wall 106. A gasket 144 may be
located between a wall facing surface 146 of shoulder 126 and the
inner surface 115 of wall 106. Rotating the threaded ring 142
relative to the threaded barrel 127 may cause the gasket 144 to be
compressed between the respective surfaces 115, 146 to form a
fluid-tight seal between the probe 63b and the wall 106 of tank 34.
The probe 63b may be oriented with the shaft in a generally
vertical orientation so that the float 120 is urged along the
length of the shaft 130 in response to the buoyant force exerted by
the washing solution 36.
[0029] Referring now to FIG. 4, the controller 58 of dispensing
system 12 may include a Human Machine Interface (HMI) 150, a
processor 152, an input/output (I/O) interface 154, and a memory
156. The HMI 150 may include output devices, such as an
alphanumeric display, a touch screen, and/or other visual and/or
audible indicators that provide information from the processor 152
to a user. The HMI 150 may also include input devices and controls,
such as an alphanumeric keyboard, a pointing device, keypads,
pushbuttons, control knobs, etc., capable of accepting commands or
input from the user and transmitting the entered input to the
processor 152. By way of example, the input and output devices of
HMI 150 may include a membrane overlay with embedded Light Emitting
Diodes (LEDs) and buttons.
[0030] The processor 152 may include one or more devices configured
to manipulate signals (analog or digital) based on operational
instructions that are stored in memory 156. Memory 156 may be a
single memory device or a plurality of memory devices including but
not limited to read-only memory (ROM), random access memory (RAM),
volatile memory, non-volatile memory, static random access memory
(SRAM), dynamic random access memory (DRAM), flash memory, cache
memory, or any other device capable of storing information. Memory
156 may also include a mass storage device (not shown), such as a
hard drive, optical drive, tape drive, non-volatile solid state
device or any other device capable of storing digital
information.
[0031] Processor 152 may operate under the control of an operating
system 158 that resides in memory 156. The operating system 158 may
manage controller resources so that computer program code embodied
as one or more computer software applications 160 (such as a
dispenser application) residing in memory 156 may have instructions
executed by the processor 152. In an alternative embodiment, the
processor 152 may execute the applications 160 directly, in which
case the operating system 158 may be omitted. One or more data
structures 162 may also reside in memory 156, and may be used by
the processor 152, operating system 158, and/or application 160 to
store data.
[0032] The I/O interface 154 operatively couples the processor 152
to other components in the operating environment, such as the
controller 28 of washing machine 10, pumps 54, 56, conductivity
circuit 59, and valve 78. The I/O interface 154 may include signal
processing circuits that condition incoming and outgoing signals so
that the signals are compatible with both the processor 152 and the
components to which the processor 152 is coupled. To this end, the
I/O interface 154 may include analog to digital (A/D) and/or
digital to analog (D/A) converters, voltage level and/or frequency
shifting circuits, optical isolation and/or driver circuits, and/or
any other analog or digital circuitry suitable for coupling the
processor 152 to the other components in the operating
environment.
[0033] The conductivity circuit 59 may include input terminals 164,
166 that are coupled to the probe 63 and an output 168. The
conductivity circuit 59 may be configured generate a conductivity
signal (e.g., a voltage) on output 168 indicative of the
conductivity and/or impedance between the input terminals 164, 166.
By way of example only, the conductivity circuit 59 may include a
signal generator 170 that outputs a stimulation signal (e.g., a
voltage), a resistor 172 coupled in series with the signal
generator 170 and at least one of the input terminals 164, 166, and
a differential amplifier 174 having inputs 176, 178 coupled across
the resistor 172.
[0034] The stimulation signal output by the signal generator 170
may cause a current to flow through the resistor 172 that is
inversely proportional to the conductivity between the input
terminals 164, 166. This stimulation current may induce a voltage
across the resistor 172, which may be amplified by the differential
amplifier 174 to produce the conductivity signal on output 168. The
conductivity signal may be transmitted to the I/O interface 154,
and may provide an indication of the conductivity between the
terminals 164, 166 of conductivity circuit 59 to the processor
152.
[0035] Embodiments of the invention using the conductivity probe
63a may have the input terminals 164, 166 of conductivity circuit
59 coupled to the electrodes 92, 94 of conductivity probe 63a. This
may result in the output signal of the conductivity circuit 59
being indicative of the conductivity of the washing solution 36.
Conventional systems may determine a concentration of chemical
product in the washing solution 36 based on small changes in the
conductivity signal, and activate one or more of pumps 54, 56 to
adjust the concentration of chemical product based thereon. In
contrast, the dispenser application of controller 58 may use the
conductivity signal to detect the presence or absence of washing
solution 36 at the probe 63a. To this end, the controller 58 may
ignore small changes in conductivity, and respond only to large
changes in conductivity.
[0036] For example, the dispenser application may determine that
the tank 34 is full of washing solution 36 based on the
conductivity signal being above a threshold, and that the tank 34
is empty of washing solution 36 when the conductivity signal is
below the threshold. The threshold level may be set so that the
dispenser application ignores changes in conductivity associated
with wash cycles due to varying levels of detergent in the washing
solution 36. By way of example, the threshold may be set to a
conductivity signal level indicative of a conductivity of the
washing solution of between 0.10 and 0.025 siemens per meter (S/m).
The threshold may be set, for example, based on the conductivity of
water received from the water source 48 so that the conductivity
signal is only below the threshold when the electrodes 92, 94 are
not covered by the washing solution 36.
[0037] In response to the conductivity signal on the output 168 of
conductivity circuit 59 falling below the threshold, the dispensing
application may determine that the washing solution 36 is being or
has been drained from the tank 34. In response, the dispensing
application may cause a predetermined amount of chemical product to
be dispensed into the tank 34, and/or cause the valve 78 to open
for a time sufficient to fill the tank 34, based on a known volume
of washing solution 36 held by tank 34, i.e., the capacity of tank
34. This dispensing of chemical product and/or washing solution 36
may be triggered in response to detecting that the conductivity has
increased above a threshold, which may indicate that the tank 34 is
being refilled. In an embodiment of the invention, the threshold
conductivity for determining that the tank 34 has been drained may
be lower than the threshold conductivity for determining that the
tank 34 is being refilled to provide a level of hysteresis to the
detection/refill process.
[0038] If the conductivity does not fall below the conductivity
threshold between wash cycles, the dispenser application may
determine that the washing solution 36 has not been drained, and
may dispense a different predetermined amount of detergent into the
tank 34 based on an expected level of dilution that occurs between
wash cycles, e.g., due to the introduction of water from a rinse
cycle. Thus, the dispensing application may determine the amount of
detergent to provide to the washing machine 10 between cycles when
the tank 34 is not drained without regard to a level of
conductivity associated with a desired concentration of chemical
product. Rather, the dispensing application may determine that the
washing machine 10 is being drained in response to the conductivity
signal dropping below one threshold level, that the washing machine
10 is being refilled in response to the conductivity signal
increasing above another threshold level, and dispense a
predetermined amount of chemical product based on the amount of
washing solution 36 held by the tank 34. In cases where the
conductivity signal fails to drop below the one threshold level,
the dispensing application may dispense an amount of chemical
product based on the amount of dilution expected between washing
cycles.
[0039] Embodiments of the invention using the float probe 63b may
have the input terminals 164, 166 of conductivity circuit 59
coupled to the switch of float probe 63b. This may result in the
output signal of the conductivity circuit 59 being indicative of
whether the switch is in an open state or a closed state. As with
the conductivity probe, the dispensing application may detect the
draining and refilling of the tank 34 based on the conductivity
signal. The conductivity signal may be indicative of a low
conductivity (e.g., at a low voltage) when the float 120 is in a
position that causes the switch to be in the open state, and
indicative of a high conductivity (e.g., at a high voltage) when
the float 120 is in a position that causes the switch to be in the
closed state. For example, when the tank 34 is refilled, the float
120 may move upward along the shaft 130. As the magnet embedded in
the float 120 approaches the magnetic switch, the input of the
probe 63b may change from an open circuit to a closed circuit.
[0040] The fixed low impedance of the switch of float probe 63b
when the switch is in the closed state may effectively replace the
impedance between the electrodes 92, 94 of conductivity probe 63a
when the probe 63a is immersed in the washing solution 36. That is,
in either case, the conductivity signal output by conductivity
circuit 59 may be below the threshold. By comparing the
conductivity signal to the threshold to determine if the tank 34
has been drained rather than determining a concentration of the
chemical product in the washing solution 36, the dispenser 52 may
operate interchangeably with either the conductivity probe 63a or
float probe 63b. The dispenser 52 may also dispense chemical
products more reliably than conventional systems that control
dispensing operations based on maintaining a level of conductivity
associated with a desired concentration of chemical product. This
may be due to the dispenser 52 having a lower sensitivity to the
conduction level of the washing solution 36.
[0041] Setting and using conductivity signal thresholds to detect
draining and filling of the tank 34 rather than a desired operating
concentration level of chemical product may enable the dispensing
system 12 to dispense chemical products more reliably than
dispensing systems lacking this feature. This feature may also
enable the dispenser 52 to operate with both conductivity and float
probes without changes to the conductivity circuit 59 or the
programming of the controller 58. Existing dispensers lacking this
feature may be updated by loading an updated dispenser application
that includes the feature as a menu option so that either type of
probe can be used without the need to update hardware.
[0042] In general, the routines executed to implement the
embodiments of the invention, whether implemented as part of an
operating system or a specific application, component, program,
object, module or sequence of instructions, or a subset thereof,
may be referred to herein as "computer program code," or simply
"program code." Program code typically comprises computer-readable
instructions that are resident at various times in various memory
and storage devices in a computer and that, when read and executed
by one or more processors in a computer, cause that computer to
perform the operations necessary to execute operations and/or
elements embodying the various aspects of the embodiments of the
invention. Computer-readable program instructions for carrying out
operations of the embodiments of the invention may be, for example,
assembly language or either source code or object code written in
any combination of one or more programming languages.
[0043] Various program code described herein may be identified
based upon the application within which it is implemented in
specific embodiments of the invention. However, it should be
appreciated that any particular program nomenclature which follows
is used merely for convenience, and thus the invention should not
be limited to use solely in any specific application identified
and/or implied by such nomenclature. Furthermore, given the
generally endless number of manners in which computer programs may
be organized into routines, procedures, methods, modules, objects,
and the like, as well as the various manners in which program
functionality may be allocated among various software layers that
are resident within a typical computer (e.g., operating systems,
libraries, API's, applications, applets, etc.), it should be
appreciated that the embodiments of the invention are not limited
to the specific organization and allocation of program
functionality described herein.
[0044] The program code embodied in any of the applications/modules
described herein is capable of being individually or collectively
distributed as a program product in a variety of different forms.
In particular, the program code may be distributed using a
computer-readable storage medium having computer-readable program
instructions thereon for causing a processor to carry out aspects
of the embodiments of the invention.
[0045] Computer-readable storage media, which is inherently
non-transitory, may include volatile and non-volatile, and
removable and non-removable tangible media implemented in any
method or technology for storage of data, such as computer-readable
instructions, data structures, program modules, or other data.
Computer-readable storage media may further include RAM, ROM,
erasable programmable read-only memory (EPROM), electrically
erasable programmable read-only memory (EEPROM), flash memory or
other solid state memory technology, portable compact disc
read-only memory (CD-ROM), or other optical storage, magnetic
cassettes, magnetic tape, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to store the
desired data and which can be read by a computer. A
computer-readable storage medium should not be construed as
transitory signals per se (e.g., radio waves or other propagating
electromagnetic waves, electromagnetic waves propagating through a
transmission media such as a waveguide, or electrical signals
transmitted through a wire). Computer-readable program instructions
may be downloaded to a computer, another type of programmable data
processing apparatus, or another device from a computer-readable
storage medium or to an external computer or external storage
device via a network.
[0046] Computer-readable program instructions stored in a
computer-readable medium may be used to direct a computer, other
types of programmable data processing apparatuses, or other devices
to function in a particular manner, such that the instructions
stored in the computer-readable medium produce an article of
manufacture including instructions that implement the functions,
acts, and/or operations specified in the flow-charts, sequence
diagrams, and/or block diagrams. The computer program instructions
may be provided to one or more processors of a general purpose
computer, a special purpose computer, or other programmable data
processing apparatus to produce a machine, such that the
instructions, which execute via the one or more processors, cause a
series of computations to be performed to implement the functions,
acts, and/or operations specified in the flow-charts, sequence
diagrams, and/or block diagrams.
[0047] In certain alternative embodiments, the functions, acts,
and/or operations specified in the flow-charts, sequence diagrams,
and/or block diagrams may be re-ordered, processed serially, and/or
processed concurrently consistent with embodiments of the
invention. Moreover, any of the flow-charts, sequence diagrams,
and/or block diagrams may include more or fewer blocks than those
illustrated consistent with embodiments of the invention.
[0048] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the embodiments of the invention. As used herein, the singular
forms "a", "an" and "the" are intended to include the plural forms
as well, unless the context clearly indicates otherwise. It will be
further understood that the terms "comprises" and/or "comprising,"
when used in this specification, specify the presence of stated
features, integers, actions, steps, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, integers, actions, steps, operations,
elements, components, and/or groups thereof. Furthermore, to the
extent that the terms "includes", "having", "has", "with",
"comprised of", or variants thereof are used in either the detailed
description or the claims, such terms are intended to be inclusive
in a manner similar to the term "comprising".
[0049] While all the invention has been illustrated by a
description of various embodiments, and while these embodiments
have been described in considerable detail, it is not the intention
of the Applicant 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. The
invention in its broader aspects is therefore not limited to the
specific details, representative apparatus and method, and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of the Applicant's general inventive concept.
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