U.S. patent application number 09/740213 was filed with the patent office on 2001-12-06 for conductance based control system.
Invention is credited to Funk, Robert C..
Application Number | 20010048958 09/740213 |
Document ID | / |
Family ID | 24975514 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010048958 |
Kind Code |
A1 |
Funk, Robert C. |
December 6, 2001 |
Conductance based control system
Abstract
The present invention relates to the system, apparatus, and
method for controllably mixing a concentrate with a dilution
substance using closed-loop feedback in order to improve the
resultant substance. The present invention discloses a system,
apparatus and method for sensing the conductivity of a diluted
substance to provide feedback information for adjusting dispensing
of a concentrate used to produce the resultant or diluted
substance. The present invention also includes a system for
dispensing beverages using the conductivity sensor such that the
system controllably adjusts the dispensing of concentrate to
maintain the resultant beverage within a desired concentration
range based on conductivity sensing. The present invention also
includes the method for sensing the conductivity of the resultant
beverage and adjusting the dispensing of concentrate in response to
the conductivity of the resultant beverage. The invention includes
a conductivity sensor coupled to a dispensing portion downstream of
the introduction of concentrate into the dilution liquid. The
conductivity of the resultant mixed beverage is measured and the
dispensing of the coffee concentrate is adjusted to maintain the
resultant beverage within a desired conductivity range.
Inventors: |
Funk, Robert C.; (Auburn,
IL) |
Correspondence
Address: |
Grant H. Peters
Barnes & Thornburg
2600 Chase Plaza
10 South LaSalle Street
Chicago
IL
60603
US
|
Family ID: |
24975514 |
Appl. No.: |
09/740213 |
Filed: |
December 18, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60172495 |
Dec 17, 1999 |
|
|
|
Current U.S.
Class: |
426/231 ;
366/17 |
Current CPC
Class: |
B67D 1/0046 20130101;
B67D 1/0043 20130101; B67D 1/1284 20130101; A47J 31/402
20130101 |
Class at
Publication: |
426/231 ;
366/17 |
International
Class: |
G01N 001/00 |
Claims
1. A system for sensing conductivity of a mixed food substance to
controllably dispense at least one of a concentrate and a dilution
substance mixed by said system to produce said mixed food
substance, said system comprising: a controllable concentrate
dispenser for controllably dispensing a food concentrate; a
controllable dilution substance dispenser for controllably
dispensing a dilution substance for diluting said concentrate; a
mixing chamber communicating with said controllable concentrate
dispenser and said controllable dilution substance dispenser for
mixing said concentrate and said dilution substance to produce said
mixed food substance; a user-interface; a conductance sensor
operatively associated with said mixing chamber for detecting the
conductivity of said mixed food substance in said system prior to
dispensing; a controller coupled to said controllable concentrate
dispenser, said controllable dilution substance dispenser, said
user interface, and said conductance sensor, said controller using
conductivity information from said conductance sensor to
controllably operate at least one of said controllable concentrate
dispenser and controllable dilution substance dispenser to control
said mixed food substance, said user-interface allowing adjustment
of said controller to define mixing parameters of said mixed food
substance.
2. A device for use with a mixed food dispensing apparatus, said
apparatus including a controllable concentrate dispenser for
controllably dispensing a food concentrate, a controllable dilution
substance dispenser for controllably dispensing a dilution
substance for diluting said concentrate, and a mixing chamber
communicating with said controllable concentrate dispenser and said
controllable dilution substance dispenser for mixing said
concentrate and said dilution substance to produce said mixed food
substance, said device comprising: a user-interface; a conductance
sensor cooperatively associated with said mixing chamber for
detecting the conductivity of said mixed food substance in said
system prior to dispensing from said mixed food apparatus; a
controller coupled to said controllable concentrate dispenser, said
controllable dilution substance dispenser, said user interface, and
said conductance sensor, said controller using conductivity
information from said conductance sensor to controllably operate at
least one of said controllable concentrate dispenser and
controllable dilution substance dispenser to control said mixed
food substance, said user-interface allowing adjustment of said
controller to define mixing parameters of said mixed food
substance.
3. A method for controlling the mixing of a mixed food substance
mixed by a mixed food dispensing apparatus, said mixed food
substance being formed from a concentrate and a dilution substance,
said apparatus including a controllable concentrate dispenser for
controllably dispensing a food concentrate, a controllable dilution
substance dispenser for controllably dispensing a dilution
substance for diluting said concentrate, a mixing chamber
communicating with said controllable concentrate dispenser and said
controllable dilution substance dispenser for mixing said
concentrate and said dilution substance to produce said mixed food
substance, a conductance sensor cooperatively associated with said
mixing chamber for detecting the conductivity of said mixed food
substance, a controller coupled to said controllable concentrate
dispenser, said controllable dilution substance dispenser and said
conductance sensor, said method comprising the steps of: operating
said controllable concentrate dispenser and said controllable
dilution substance dispenser to dispense said concentrate and said
dilution substance; mixing of said concentrate and said dilution
substance in said mixing chamber for producing said mixed food
substance; passing of said mixed food substance in contact with
said conductance sensor; sensing of a conductance of said mixed
food substance; comparing said conductance of said mixed food
substance to a desired conductance of said mixed food substance;
controllably operating at least one of said controllable
concentrate dispenser and controllable dilution substance dispenser
to adjust the conductance of said mixed food substance dispensed
from said apparatus to a desired conductance.
Description
CROSS-REFERENCE
[0001] This application claims priority under 35 U.S.C. 119(e) to
U.S. Provisional Application Serial No. 60/172,495 filed Dec. 17,
1999 which is expressly incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to a novel system for
controlling the mixture of concentrate with a dilution substance in
a beverage preparation system. The invention also includes the
method and apparatus of the system which achieves the control of
the mixing of concentrate in a beverage preparation system.
[0003] By way of review, there are numerous beverage preparation
systems which use a concentrate substance to prepare a beverage.
Typically, the concentrate substance is diluted with another
substance to prepare the desired resultant beverage. More
specifically, there are coffee and juice concentrate systems which
use a prepared coffee or juice concentrate. We will refer to coffee
for the present discussion with the understanding that other
beverages, such as juice, are included in the discussion. The
coffee concentrate might be provided in a liquid form either at
room temperature or, for example, in a frozen state. The packaged
concentrate in this form might be referred to as a "bag-in-box"
packaged concentrate, and the system dispensing such concentrate
might be referred to as a "bag-in-box" system. In such a system, a
concentrate retained in a container is connected to a system which
dilutes the concentrate with a predetermined quantity of water.
Typically, when making coffee, these systems use heated water so as
to produce a heated coffee beverage. Such systems meter out a
predetermined quantity of the concentrate to be mixed with the
predetermined quantity of dilution water.
[0004] Such prior art systems also extend to powdered or solid
beverage concentrate systems. In this regard, powdered beverage
substances such as coffee, juices or other beverages can be diluted
either to produce a single cup serving, larger volumes, or to
refill a common supply tank. In these systems, the powdered
beverage substance is mixed with the dilution water and dispensed
into the corresponding container. In such systems, a predetermined
volume, weight or quantity of powder is dispensed and mixes the
material with a predetermined quantity of water. The dilution
system of the prior art can extend to systems which utilize a
freshly brewed concentrate such as taught in U.S. Pat. No.
4,757,752 to Robins et al. In the Robins' device, a tea concentrate
is brewed and retained at a desired temperature range. The tea
concentrate is then diluted on demand. In the system of Robins, the
concentrate is diluted based on volume settings.
[0005] It is expected that there are other beverage and substance
dispensing and diluting systems which are similar to or identical
to that as described hereinabove. It is also believed that many of
these systems would greatly benefit from the present invention
which provides improved accuracy, consistency, repeatably, and
uniformity as provided by the present invention.
OBJECTS AND SUMMARY
[0006] The present invention relates to the system, apparatus, and
method for controllably mixing a concentrate with a dilution
substance using closed-loop feedback in order to improve the
resultant substance.
[0007] More specifically, the objective of the present invention is
for use in combination with a concentrate based beverage dispensing
system which monitors the conductivity of the diluted substance and
provides feedback to adjust the dispensing of the concentrate.
[0008] Another object of the present invention is to provide a
system for dispensing beverages which uses closed-loop feedback
based on the conductivity of the diluted beverage to adjust the
dispensing of concentrate.
[0009] Still a further object of the present invention is to
provide a method of mixing a beverage concentrate with a dilution
substance to produce a resultant beverage in which the conductance
of the beverage is monitored for adjusting the dispensing of
concentrate.
[0010] Briefly, and in accordance with the foregoing, the present
invention discloses a system, apparatus and method for sensing the
conductivity of a diluted substance to provide feedback information
for adjusting dispensing of a concentrate used to produce the
resultant or diluted substance. The present invention also includes
a system for dispensing beverages using the conductivity sensor
such that the system controllably adjusts the dispensing of
concentrate to maintain the resultant beverage within a desired
concentration range based on conductivity sensing. The present
invention also includes the method for sensing the conductivity of
the resultant beverage and adjusting the dispensing of concentrate
in response to the conductivity of the resultant beverage. The
invention includes a conductivity sensor coupled to a dispensing
portion downstream of the introduction of concentrate into the
dilution liquid. The conductivity of the resultant mixed beverage
is measured and the dispensing of the coffee concentrate is
adjusted to maintain the resultant beverage within a desired
conductivity range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The organization and manner of the structure and operation
of the invention, together with further objects and advantages
thereof, may best be understood by reference to the following
description, taken in connection with the accompanying drawings,
wherein like reference numerals identify like elements in
which:
[0012] FIG. 1 is a diagrammatic illustration of the conductivity
sensor and system which incorporates the features of the
invention;
[0013] FIG. 2 is a schematic of a sensor circuit used to sense the
conductivity of the resultant beverage;
[0014] FIG. 3 is a diagrammatic illustration of an example of a
concentrate system of the invention; and
[0015] FIG. 4 is a chart of signal waveforms of conductance sensor
operation.
DESCRIPTION
[0016] While the invention may be susceptible to embodiment in
different forms, there is shown in the drawings, and herein will be
described in detail, specific embodiments with the understanding
that the present disclosure is to be considered an exemplification
of the principles of the invention, and is not intended to limit
the invention to that as illustrated and described herein.
[0017] The present invention provides a novel system, apparatus and
method 20 for controllably combining a concentrate substance 22
with a dilution substance 24 such as heated water to produce a
resultant beverage 26. With reference to FIG. 1, the system 20 is
shown diagrammatically and includes a novel dilution assembly 28
using a novel conductance sensor 30. The dilution assembly 28 is
coupled to a concentrate dispenser 32 and a dilution substance
dispenser 34. In a preferred embodiment the concentrate dispensers
32 dispense a liquid or solid concentrate, as well as any other
form of concentrate which might be applicable in the preparation of
food substances.
[0018] While concentrate is referred to in this application, it is
envisioned that other substances may be used and the present
invention broadly includes such other substances, variations,
alternates, equivalents, substitutes, and/or combinations. For
example, for food substances such as soups, a base may be used and
reconstituted with water. In this example, while the base may or
may not be concentrated, it is combined with water to produce the
resultant soup. Similarly, the invention may be used to prepare
substances which are concentrated in order to prepare the substance
in a more useful form. For example, a chocolate powder may be
prepared using the invention to produce a liquid chocolate
concentrate in a concentration which may be preferable for mixing
with other substances such as coffee. In this regard the liquid
chocolate may be used to mix with coffee and avoid potential powder
mixing problems such as clumping.
[0019] With the foregoing in mind, the description is generally
directed to the preparation of a beverage and specifically
described as the preparation of coffee. However, it should be
appreciated that other foods might also be prepared using this
system and its structures and such systems are fully included
within the scope of the present invention. Moreover, description in
the present application is directed to a diluted substance
dispenser 34 which uses hot water. However, it should be
appreciated that other liquid substances may be used to dilute or
mix with the concentrate such as coffee, tea, carbonated water,
milk products, or other substances. Additionally, the present
application also includes other devices which may be used to
combine the concentrate 22 and the dilution substance 24. For
example, mechanical agitators, heaters, or coolers should be fully
considered as contemplated in the present invention.
[0020] With reference to FIG. 1, an interface 36 is provided in the
system 20. The interface 36 may be as uncomplicated as on/off
switches or controls or may involve detailed computer based
user-interface selections. Such user-interface selections may
involve the user inputting specific criteria about the desired
resultant food substance, may involve a memory or recognition
device which associates information regarding the user and the food
substance or a combination of such devices. Regardless of its
degree of complexity, the interface 36 is coupled to a controller
38 which controls the system in response to inputs from the
interface 36. The controller 38 is coupled to the dilution
substance dispenser 34, concentrate dispenser 32, and the
conductance sensor 30. When the user-interface 36 is activated, a
signal is transmitted via line 40 to the controller 38. The
controller 38 then responds to the signal 40 and controllably
operates the dilution substance dispenser 34 (via line 41) and
concentrate dispenser 32 (via line 43) to dispense a pre-determined
quantity of dilution substance 24 and concentrate 22 into the
dilution assembly 28.
[0021] One of ordinary skill in the art will appreciate that
appropriate connections, couplings or conduits (42, 44) are
provided to permit the dispensers 34, 32 to communicate with a
corresponding chamber 46 of the dilution assembly 28. The
concentrate 22 and dilution substance 24 are mixed in the chamber
46 to produce a desired resultant beverage 26.
[0022] The conductance sensor 30 is coupled to the chamber,
generally positioned at least slightly downstream from the initial
mixing of the concentrate 22 and the dilution substance 24. The
conductance sensor 30 is positioned downstream in order to allow at
least some mixing of the concentrate 22 and the dilution substance
24 before it is monitored for conductivity. The conductance sensor
30 includes a conductivity sensing circuit 48 which includes two at
least slightly spaced-apart contacts or probes in the form of a
first 50 and second 52 generally cylindrical electrodes. The
electrodes 50, 52 are spaced apart by a non-conductive or
dielectric portion 54 such as a silicone tube. The conductivity
sensing circuit 48 is coupled to the associated sensing circuit 48
of the controller 38 by line 56. As shown in FIG. 1, a spacer 57 of
a dielectric material is provided to space apart the electrodes 50,
52. Conductive threaded studs 59, 61 are provided on the electrodes
50, 52 and are attached to the spacer 57 with nuts 63, 65. Lines
56a, 56b are attached to the conductive studs 59, 61. It should be
noted that the electrodes 50, 52 may be in any of a variety of
suitable forms and are not limited to the generally cylindrical
electrode configuration as illustrated. The electrodes may be in
the form of probes extending into the stream or areas contacted by
some portion of the stream such as a conductive area on the inside
of the structure containing the stream.
[0023] Continuing the dispensing of a resultant beverage as
initially discussed above, the conductivity sensing circuit 48
provides conductance measurements 56 of the resultant beverage
during the dispensing of the desired quantity of beverage. In this
regard, the conductance of the resultant beverage can be used to
adjust the dispensing of the concentrate 22 and the dilution
substance 24 from the corresponding dispensers (32, 34) to maintain
the conductance of the resultant beverage 26 within a desired
range. The signal 56 is processed by the controller 38 which then
makes adjustments to the dispensing from the dispensers 34, 32
throughout the beverage production cycle. The adjustment of the
concentrate dispensing throughout the beverage dispensing cycle
helps to increase the consistency, repeatability, uniformity and
accuracy of the concentration of the concentrate in the dilution
substance.
[0024] In contrast, prior art devices typically dispense a volume
or time-metered quantity of concentrate and dilution substance. If
there were some deviation in either of these substances from some
standard level or range of acceptable levels, the resultant
beverage would be outside of the desired acceptable level.
Moreover, if the tolerances of acceptable levels of dilution
substance of concentrate became cumulative, such that independently
each component was within its desired range but cumulatively the
combination was outside the desired range, there would be an effect
on the resultant beverage. The effect on the resultant beverage
would be manifested in the form of changes in the flavor
characteristics and flavor profile. The change in these
characteristics results from increased characteristic components in
the concentrate as well as the dilution substance. This closed-loop
system shows improved performance compared to prior art, from the
standpoint of the limitations of prior "open-loop" systems that
merely dispense for a fixed period of time from the concentrate and
dilution (hot water) channels. Such prior art systems yield varying
finished-beverage results when: the viscosity of the concentrate is
high and variable enough that flow rate through the pumping means
cannot be precisely predicted from run-time alone; the dilution
channel flow is based on gravity flow from a reservoir with varying
water level, thus varying flow rate; or the concentration of flavor
components in the beverage concentrate is not consistent over time,
thus a fixed volumetric dilution is not adequate to ensure
consistent finished-beverage flavor.
[0025] While control of both substance dispensers 34, 32 may be
achieved using the present system 20, precise control of the
dilution substance dispenser 34 may not be necessary when only
water is being dispensed to dilute a beverage concentrate 22 such
as coffee concentrate. In this regard, a time-metered or
volume-metered quantity of heated water may be dispensed from the
dispenser 34 and adjustment to the conductivity of the resultant
beverage 26 being controlled by controlling the concentrate
dispenser 32. The closed-loop system of the present invention
improves the consistency of the resultant beverage 26 by more
accurately controlling the dispensing of concentrate 22 into the
hot water stream 24. The conductance sensing circuit 48 and
controller 38 calculate the conductance to determine the
concentration of the resultant beverage 26 and provide controlled
variation of the dispensing rate of the concentrate 22 into the
blending chamber 46. This requires that the concentrate dispenser
32 is adjustably controllable.
[0026] While a variety of concentrate dispensers 32 might be
employed in the present invention, the dispensing system as
disclosed in U.S. patent application Ser. No. 09/602,908, filed
Jun. 23, 1999 entitled Concentrate Pump System identifying Kevin G.
Lowe and Robert C. Funk as inventors, provides a highly accurate
controllable system which benefits from the conductance sensing of
the present invention. The disclosure of this application is
incorporated herein by reference in its entirety. The controller 38
is pre-programmed with information about the control of the
dispenser 32 so that when a specific conductivity is sensed by the
conductance sensor 30, if necessary, adjustment of the flow rate of
the dispenser or pump 32 can be made in response thereto.
[0027] With reference to FIG. 3, a concentrate dispenser 32 is
shown diagrammatically employing elements also disclosed in the
above referenced application. The dispenser 32 includes a reservoir
58 coupled to a pump 60 coupled to a gating device 62. The pump 60,
in a preferred embodiment, a peristaltic pump in accordance with
the teachings of the above referenced application, draws
concentrate from the reservoir 58. The concentrate is advanced from
the pump 60 to the gating device 62. The gating device 62 is
controllably operated to more precisely control the flow from the
pump 60. As a result, with further reference to FIG. 1, a precise
quantity of concentrate can be dispensed from the concentrate
dispenser 32 through the conduit 42 communicating with the blending
chamber 46. It should be noted that while some dispensing devices
may require only one control line with the controller, two
controlled signals may be required for the embodiment of the
dispenser 32 as shown in FIG. 3. In this regard, independent
control of the pump 60 and the gating device 62 may provide more
accurate control of the dispenser 32.
[0028] The system monitors conductance of the concentrate "on the
fly" and allows the adjusting of the variable speed pump 60 and the
gating device 62 to precisely control the amount of concentrate
injected into the dilution stream.
[0029] The present invention helps to adjust the system to assure
consistent blend strength since the conductivity of the beverage is
related to the blend strength. For example, the concentrate in
combination with the dilution water 24 is measurably more
conductive than the water prior to mixing with concentrate.
[0030] Another benefit of using the dispenser 32 as shown in FIG. 3
is that the gating device tends to reduce or eliminate the
"pulsing" of liquid through the conduit 42 thereby providing a more
uniform flow. This will increase the uniformity of the mixture with
the heated water and dispensing of a consistent beverage from the
exit port 64 of the dilution assembly 28. This reinforces and
enhances the visual characteristics of the brewed beverage to the
consumer.
[0031] The conductivity circuit 48 senses the conductance of
various substances and can be adjusted for the type of substance
being dispensed. The conductance reading or measurement is used as
a characteristic of the concentrate in the resultant beverage 26.
For example in coffee, the conductivity measurement is related to
the caffeine, acid, and solids (total dissolved solids) in the
coffee concentrate. Also, in juice products, the conductance
measurement is related to the acids in the juice. Of course, the
system can be adjusted based on the type of concentrate used in the
characteristics of the concentrate. Generally, this system relies
on the ionic molecules in the particular concentrate as
conductors.
[0032] Additionally, a range of acceptable levels of conductance
(concentrate) can be set for a particular type of beverage. The
predetermined range and the variability of the concentrate
injection into the dilution stream 24 helps accommodate variations
in batches of concentrate regardless of whether the concentrate is
in a prepared liquid form, fresh prepared liquid form, powdered
form, or other form. While the variability of the substance used to
prepare the concentrate may change from batch to batch or the
processing techniques may vary slightly based on manufacturing
tolerances of the concentrate, the adjustments resulting from the
present system helps assure a consistent resultant beverage 26.
[0033] The present system 20 accommodates ranges for several
variables. For example, the system can be adjusted to take into
account the temperature of the substance. In this regard,
conductivity is generally consistent at elevated temperatures
whereas conductivity tends to be reduced with a decrease in
temperature. A control can be provided on the controller unit 38 or
the conductivity circuit 48 to adjust the range upwardly or
downwardly. This may be used to adjust the system for regional
tastes, for example, to make a batch of coffee stronger or weaker.
However, the control may also be limited to a specific desired
range while still providing adjustment within that range upwardly
or downwardly. As an additional consideration, the circuit 48
senses AC conductance. AC conductance is used in order to prevent
plating of the molecules on the electrodes 50, 52. Also, a triac is
used to change energy to the solenoid to control the gating device
62 to control the flow therethrough.
[0034] The conductance sensor 30 can be used to sense an empty
dispenser 32 condition. For example, if the sensor 30 senses a
dramatic change in conductance, this would tend to indicate either
the absence of concentrate or dilution liquid in the dispenser 32
or a blockage preventing concentrate 22 or dilution liquid from
entering the blending chamber 46. In either situation, this
condition can be identified to the user whereby troubleshooting can
occur to solve the problem. Furthermore, in a highly automated
system, the low or no concentrate signal sensed by the sensor 30
can be used to initiate a refill cycle whereby concentrate stock
can be dispensed from a corresponding brewer 68 coupled to the
controller 38. This might be in the very basic form as shown in the
Robins et al. patent mentioned in the Background section of this
application.
[0035] With reference to the circuit of FIGS. 2 and 4, a portion of
the sensing circuit 48 is shown. As generally shown, the micro
controller 72 outputs a square wave which makes position transition
at t1. The analog to digital input voltage 74 fed to the analog to
digital converter 76 is read at t2. The conductance of the portion
of the resultant beverage in the sensing chamber 78 at a given time
interval is related to the analog to digital reading. The
conductance is detected and the measurement is used in determining
whether to accelerate or decelerate the variable speed pump and
gating device 60, 62 used in the dispenser 32. It should be noted
that the average current is zero in order to eliminate buildup on
the electrodes 50, 52. The lower sensing electrode 52 is generally
connected to circuit ground and earth ground such that any external
surface contacted by the delivered beverage will not affect the
conductance reading of the sensor. The effective parallel
conductance of the concentrate line 42 is not significant due to
its length and small cross-section; the effective parallel
conductance of the water from line 44 is not significant due to the
relatively low conductance of water. This is consistent with the
use of AC in the system to prevent plating. It should also be noted
that diodes 80, 82 are provided to protect the gate 84 and input to
the analog to digital converter. The schematic of FIG. 2 and
examples of wave forms in FIG. 4 show how the microcontroller 72
and A/D converter can rapidly determine a conductance reading with
no DC current through the sensor. The reading or measurement is
used, for example, to determine the concentration of coffee
components in a blended beverage.
[0036] The measured conductivity is based on the peak reading among
several readings taken over an interval which includes individual
A/D readings at consecutive "t2" events; this further ensures that
the occasional air bubble will not introduce confusing control
responses.
[0037] The control algorithm implements an integrating response
with variable gain, such that the rate at which the concentrate
dispenser's drive responds to a measured error in conductivity is
set to not over-react to normal variations in measured
conductivity, such as might occur with the introduction of an
occasional air bubble into the sensing chamber.
[0038] The user can adjust the delivered beverage strength with a
simple control (e.g. rotary control knob) connected to the
controller which adjusts the target to which the closed-loop
control adjusts average conductance readings.
[0039] Turning now to FIG. 1, the dilution assembly 28 includes the
generally cylindrical electrodes 50, 52. The electrodes are also
formed in a reduced diameter or necked-shape so as to generate a
degree of mixing turbulence in the blending chamber 46 as the hot
water 24 and concentrate 42 are injected therein. The tapered
section 50 tends to inhibit the introduction of air bubbles into
the sensing chamber between 50 and 52, which would have confounded
the accurate sensing of the conductance of the blended liquid
beverage. The turbulence restricts the outflow of the blended
beverage through the exit port 64. This produces a degree of
buildup in the blending chamber 46. The mixing and blending of the
concentrate with the water helps assure that it is thoroughly
mixed. This is important for an accurate reading for insuring that
the sensing chamber 78 is full of liquid when sensing conductivity
and that the concentrate and water are thoroughly mixed together to
prevent striation or layering. A partially full conductivity
chamber might result in an inaccurate reading as well as striation
creating inconsistent reading. The controller 38 is programmed with
a brief delay (for example, one second) when the dispensing cycle
is initiated. The brief delay insures that the sensing chamber 78
is full of liquid before measurements are taken. This helps to
assure that the system does not overreact to the initial, perhaps
inconsistent, mixture of beverage which is used to fill the sensing
chamber 78.
[0040] With further reference to FIG. 1, a columnating device 84 is
provided in the electrode 52 proximate to the exit port 64. The
columnating device 84 helps to reduce the swirling and turbulence
which might otherwise be present at the exit port 64. By
columnating and directing the flow in a generally vertical
direction, the potential for splashing at the exit port 64 is
minimized or prevented. The columnating device 84 as shown in FIG.
1 is generally multi-vaned device. It should be noted that a single
blade device such as in taught in U.S. Pat. No. 5,423,245 issued
Jun. 13, 1995 could be used for this purpose as well.
[0041] Near the completion of the dispensing cycle, dispensing of
the concentrate is ceased and a small quantity of water is used to
rinse the dilution assembly 28. By rinsing at the end of the
dilution cycle, the dilution assembly 28 can be kept clean and
sanitary thereby further improving the efficiency of the invention.
Such cleaning also helps maintain the accuracy of the system by
keeping the electrode surfaces clean at the end of a mixing
cycle.
[0042] While a preferred embodiment of the present invention is
shown and described, it is envisioned that those skilled in the art
may devise various modifications and equivalents without departing
from the spirit and scope of the invention as defined by the
appended claims. The invention is not intended to be limited by the
foregoing disclosure.
* * * * *