Beverage dispenser with automatic ratio control

An automatic ratio control system for a single or multiflavor post-mix beverage dispensing valve of a beverage dispenser including a flow meter in each syrup and water conduit, a temperature sensor in each syrup conduit, an adjustable flow control in each syrup and water conduit, an automatic flow control adjuster, and an electronic control system including a microprocessor and appropriate software for adjusting a particular flow control when a measured flow rate falls outside of a range of preferred flow rates.

BACKGROUND OF THE INVENTION 
This invention relates to post-mix beverage dispensers and in particular to 
a beverage dispensing valve system providing automatic ratio control. 
SUMMARY OF THE INVENTION 
Monitoring and testing of mechanical flow controls for beverage dispensing 
valves such as that known as the piston/sleeve or pressure compensating 
flow control presently used on dispensing valves to control the ratio of 
the syrup to water of the beverage dispensed from the dispensing valve 
tend to drift out of adjustment after a period of time such as between one 
to four weeks. In the past, it has been necessary for restaurant or 
service personnel to daily or weekly test for ratio accuracy and to then 
manually set the flow controls if they were found to be out adjustment. 
The automatic ratio control system of the present invention is capable of 
monitoring and adjusting the flow controls on an ongoing basis, with no 
interaction from personnel. The present invention uses flow meters such 
as, for example, a paddle wheel pulse type flow meter, positioned in each 
of the liquid supply tubing to continuously monitor the flow rate of each 
liquid and also includes an automatic adjusting mechanism, aptly termed 
the electronic screwdriver, that can make adjustments to the flow control, 
such as at the time that a flow error trend is detected. Data from the 
individual liquid lines (including the carbonated water or soda line, the 
plain water line and the individual syrup lines) is retained in the memory 
of a microprocessor from several recent pours in order to analyze and 
interpret a flow trend error. This technology can be adapted and 
retrofitted for any single or multiflavor valve that uses adjustable flow 
controls. 
In a preferred embodiment of the present invention the present invention 
includes a mechanical flow control adjuster that includes a stepper motor 
and a movable carriage with a solenoid that locates the flow control to be 
corrected and then performs the adjustment thereon, hardware and software 
to monitor the flow meters and detect flow trend errors and then to 
control the adjuster mechanism. The present invention includes several 
major components: (1) a flow control adjuster mechanism; (2) flow meters 
which are placed in the syrup and water lines before or after the cooling 
device and which then send information (which may be electronic pulses) to 
the control system based on the flow rate; (3) control system including 
the hardware and the software. 
It is an object of the present invention to provide an improved post-mix 
beverage dispenser which includes means for automatically controlling the 
ratio of syrup to water in the dispensed beverage. 
It is another object of the present invention to provide a method and 
apparatus for controlling the ratio of syrup to water in a beverage 
dispenser. 
It is another object of the present invention to provide a beverage 
dispensing valve system including one or more single and/or multiflavor 
valves, with means for automatically monitoring and controlling the ratio 
of syrup to water in each of the beverages dispensed therefrom. 
It is another object of the present invention to provide a beverage 
dispensing valve system with a mechanically adjustable flow control, a 
flow meter in each of the liquid lines and a microprocessor for 
automatically energizing the flow control adjuster whenever the measured 
flow rate falls outside of a preferred flow rate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference now to the drawings, FIGS. 1 and 2 show a post-mix beverage 
dispenser 10 according to the present invention having an automatic ratio 
control system 12 for controlling the ratio of syrup to water in the 
beverage dispensed therefrom. 
The dispenser 10 includes a dispensing valve 14 including a nozzle 16 and 
spout 18 for dispensing a beverage into a cup 20 positioned on a cup rest 
22. The valve 14 and nozzle 16 are preferably a multiflavor valve and 
nozzle and the dispenser 10 includes a plurality of syrup lines (one of 
which is shown at 24) and a soda (carbonated water) line 26. There is an 
inlet water line to the dispenser and both a soda line and a plain water 
line to the valve 14. Various known features of a dispenser, such as the 
carbonator and refrigeration system, are not described herein in detail. 
In the preferred embodiment, the valve 14 is an eight flavor valve and thus 
ten liquid conduits or lines are used, including eight syrup lines, one 
soda line and one plain water line. 
The automatic ratio control system 12 includes the valve 14 and the 
electronic system 28. The valve 14 includes eight syrup conduits (one of 
which 24 is shown), a soda conduit 26, a plain water conduit, a solenoid 
controlled on-off valve 30 in each conduit, a flow meter 32 in each 
conduit, a temperature sensor 34 in at least each syrup conduit, an 
adjustable flow control 36 in each conduit, and a mechanical flow control 
adjuster 38. 
The automatic ratio control system of this invention includes means for 
measuring the flow rate through each conduit (the flow meters 32 and 
temperature sensors 34), means for automatically comparing the measured 
flow rates with preferred ranges of flow rates (the electronic system 28), 
and means for automatically adjusting the flow controls at appropriate 
times. The flow meters 32 can be of any type such as paddle wheel flow 
meters with flow sensors 35 for sensing rotation of the paddle wheels. 
The preferred embodiment of the automatic flow control adjuster 38 will now 
be described, followed by a description of the electronic system 28. 
The automatic flow control adjuster 38 includes a flow control sprocket 
wheel 40 connected through a shaft 41 to each of the flow controls 36 and 
a movable actuator 42 for controllably rotating a selected one of the 
sprocket wheels 40. The sprocket wheels are preferably arranged in a 
linear array and may or may not be equally spaced apart. 
The movable actuator 42 includes a single drive sprocket 44, positioning 
means 46 for moving the drive sprocket into mating contact with any 
selected one of the flow control sprockets, and drive means 48 for turning 
the drive sprocket and in turn the selected flow control sprocket, a 
desired amount. 
The movable actuator 42 will now be described in detail with reference to 
FIGS. 1-6. The actuator 42 includes a stationary support 50 and a movable 
carriage 52 mounted for sliding movement thereon and carrying the single 
drive sprocket 44. The drive sprocket 44 is moved out of mating engagement 
with a flow control sprocket wheel 40 when the carriage is moved by the 
positioning means and when the carriage movement is completed, the drive 
sprocket 44 is then moved into mating engagement with the selected flow 
control sprocket at which time the drive means 48 can turn the selected 
flow control sprocket wheel the desired amount. 
The stationary support 50 includes the linear array of flow control 
sprocket wheels 40, a stepper motor 56, a drive chain 58, a chain movement 
sensor 60 including a toothed wheel 61 and a photosensor 62 to read 
movement of the wheel and therefore of the chain, a locking rail 64 with a 
plurality of locking pin detents 66 to lock the carriage 52 in place in 
any one of a number of selected positions, a position rail 68 with a 
plurality of position holes 70 for locating a selected position, a 
plurality of carriage guide rods 72, and a home position photodetector 74. 
The movable carriage 52 includes a carriage body 76, a plurality of guide 
blocks 78 slidably mounting the carriage on the guide rods 72, the drive 
sprocket 44 rotatably mounted on a drive sprocket axle 80 which in turn is 
connected to a vertically movable slide 82 having an upper carriage travel 
position and a lower flow control adjusting position, a solenoid 84 which 
when energized moves the slide up to its carriage travel positions against 
the action of a bell crank return spring 86, a position seeking 
photodetector 88 positioned to sense said position holes 70 in said 
position rail, a home position sensor tab 90, a locking pin 92 mounted on 
a locking pin slide 94, a bell crank 96 pivotably movable about a pivot 
shaft 98 and having a locking pin slide cam 100 and a cam slot 102 for the 
drive sprocket slide 82. In addition, a drive belt locking lug 104 is 
mounted above the drive sprocket to hold the drive chain thereto when the 
solenoid 84 is energized so the carriage 52 will move with the drive chain 
58. A pair of idler rollers 106 guides the chain onto the drive sprocket. 
A pair of springs 108 bias the locking pin slide 94 downwardly. 
Thus, in operation, the carriage is preferably positioned at its home 
position with the drive sprocket 44 in mating engagement with the left 
most flow control sprocket wheel (as viewed in FIG. 3). When the 
electronic system 28 determines that a particular flow control should be 
adjusted a certain amount, the solenoid 84 is energized causing the 
solenoid armature 110 to pull up rotating the bell crank 96 and first 
raising the slide 94 to move the locking pin 92 out of the detent 66 and 
then raising the slide 82 to move the drive sprocket 44 away from a 
sprocket wheel and holding the drive chain 58 to the drive sprocket. 
The stepper motor 56 is then energized to move the drive chain and thus the 
carriage 52 until the carriage reaches the desired location as sensed by 
the position seeking photodetector 88. The solenoid 84 is then 
de-energized to lock the carriage in place and to move the drive sprocket 
44 into mating engagement with the flow control sprocket wheel 40 of the 
selected flow control 36 to be adjusted. The further movement of the drive 
chain 58 as controlled by the electronic system rotates the flow control 
sprocket wheel the amount determined to be necessary to adjust the flow 
controlled thereby. The turning of the flow control sprocket wheel adjusts 
the flow control in the same manner as done manually in the prior art by a 
screwdriver, and thus such need not be described here. The amount of 
rotation is determined by the following data: (1) 1 full rotation of the 
flow control equals "X" oz/sec. flow rate change, (2) 1 full rotation 
equals "Y" stepper motor steps, and (3) present flow rate minus desired 
flow rate equals "Z" oz/sec. Then the appropriate number of steps are 
relayed to the stepper motor. The toothed wheel 61 detects a flow control 
that is full in or full out to send an error message. 
FIGS. 4A, 4B and 4C show the positions of the various elements as the 
solenoid 84 is energized and begins to turn the bell crank 96. FIG. 4A 
shows the various positions of the elements when the solenoid is not 
energized and FIG. 4C shows the various positions of the elements after 
they have completed their movement. FIG. 4B shows the positions of the 
various elements after the bell crank has moved about half way through its 
rotation. It is noted that the locking pin 92 is completely disengaged 
from the locking pin detents in the rail 64 before the drive sprocket 
moves up and holds the drive belt against the lug 104. 
The electronic control system of this invention will be evident to anyone 
skilled in the art by reference to FIGS. 7-12 which show the software and 
the electronic schematics. However, for the benefit of those not skilled 
in the art, the following additional explanation may be of benefit. With 
reference first to FIGS. 7-10, upon power up, the electronic control 
system of this invention, hereinafter the VQM (or valve quality monitor), 
sets status bytes to request information about the type of equipment it is 
connected to and the beverage line information (what syrup is running 
through which line). It also receives information concerning the desired 
ratio settings and flow rates as well as whether the beverage is 
carbonated or not. 
Referring mainly to FIG. 10, the VQM then sets a byte to request an 
initialization of the beverage dispenser system. The initialization 
process consists of dispensing a series of 2 second draws for every syrup, 
each draw followed by an adjustment to the flow control if necessary (an 
adjustment is made if the flow rate error is outside, for example, (.+-.4% 
error). This is done automatically by the VQM software with no interaction 
from the store personnel. When all of the circuits have been adjusted to 
within the specified error, the store personnel is notified and the VQM 
enters its normal operation mode. 
Referring now primarily to FIG. 8, the VQM then remains idle until signaled 
by the dispenser control board that a beverage is being dispensed. The 
information passed to the VQM includes the syrup line and water or soda 
line currently in use. The VQM then goes to the respective flowmeters and 
monitors pulses. This data, the period between pulses paired with syrup 
viscosity data is then interpreted into ounces of fluid dispensed. A timer 
is running throughout the data collection period, so that at the end of 
the dispense the total ounces is divided by the total ounces to calculate 
the fluid flow rate. This is done for the syrup and the water 
individually. 
Referring now primarily to FIG. 7, this flow rate is compared to the 
desired flow rate and a flow rate error is then stored into a queue. There 
is a specific queue for each flow control that is to be adjusted. 
Therefore, whenever a carbonated Beverage 1 is dispensed, a value is 
stored into the carbonated water queue and a value is stored in that 
respective syrup (Beverage 1) queue. When a queue has reached a length of 
100, the average error of the flowrate is calculated. If this error is 
above .+-.1% then a calculation is done to see what the adjustment to the 
flow control should be. Otherwise, the 101st dispense of this fluid is 
entered into the queue, the very first dispense is deleted and the average 
error of the last 100 drinks is calculated. This continues until an error 
of greater than .+-.1% is calculated on the last 100 drinks dispensed 
through any of the beverage lines. 
##EQU1## 
Referring now primarily to FIG. 9, when this error is encountered, a 
calculation is performed that uses the information gathered over the last 
100 drinks. The amount of adjustment is determined by using a constant 
value for sensitivity for the flow control (ounces/sec per full 360 degree 
turn of the flow control), the stepper motor steps required for one full 
rotation of the flow control and the desired flow rate and the error. 
Knowing these four values leads to the number of steps needed to be sent 
to the stepper motor using the following equation. 
The VQM then sends motor steps in order to move the carriage to the 
appropriate flow control, it's position determined by the position sensor 
getting pulses every time it passes a flow control position. For example, 
if the carriage was to go to flow control 5, it would continue to send 
steps to the motor until it receives 5 pulses from the position sensor. 
Then the motor pulses stop and the solenoid on the carriage is 
de-energized. The VQM then sends the specified number of step pulses in 
the specified direction (a positive number from the equation identifies a 
clockwise turn, a negative number a counter-clockwise turn) to the stepper 
motor. When the adjustment is finished the adjuster returns to the home 
position until another flow control has an adjustment required. The queue 
used to determine the flow control error trend is then emptied and another 
adjustment cannot occur on this particular flow control until at least 100 
drinks of that flavor have been dispensed, in the presently preferred 
embodiment. Clearly other numbers can be used. 
In the flow control has bottomed out in either direction and an adjustment 
is attempted to go further in that particular direction, a sensor has been 
added to alert an error condition. This sensor consists of the 
photoelectric eye 62 that is placed on either side of a slotted wheel 61 
that is attached to one of the chain sprockets. The pulses from the sensor 
must keep coming to the processor at a steady rate or else it is 
determined that the chain is not moving, therefore the sprocket attached 
to the flow control is not moving, and the flow control must be bottomed 
out. This error is relayed to the store personnel as a possible hydraulic 
limit (in that the adjustment was to increase flow and the system 
pressures were not high enough to permit such a flow rate) or another 
error. 
Referring now primarily to FIG. 7, the VQM system is also monitoring the 
standard deviation of each flow control's queue of errors. It is known 
that the flow control has a deviation of about 3%. If the deviation is 
more than 5%, a warning is given to store personnel that the flow control 
in that certain circuit is possibly bad and needs to be replaced. 
Communication between the VQM and a beverage dispensing system can be done 
via an RS422 full duplex line. The host or master for the communication is 
the beverage dispensing system, the slave being the VQM. The messages sent 
include the settings data at power up or as requested by a bit set in the 
VQM status. This status is requested by the host system and is 
communicated at least every second. Error and warning messages may be sent 
to the dispensing system through this communication line. 
Referring now to FIGS. 11 and 12, the electronics consists of a circuit 
board with an Intel 80C196 microprocessor that monitors the flowmeters 32 
and the drink switches (or receives status information from an operator 
panel) and controls the adjuster mechanism. There are a total of 17 
connectors, ten for the flowmeter input (5 pins: sensor return, pulses, 
5V, ground, and thermistor analog), one for the adjuster (16 pins: 24 VDC 
and phase to the stepper motor, 24 VDC to the solenoid, rotation, 
in-position, and home sensor power and signal, and ground), three can be 
dedicated for communication, of which one can be for a serial 
communication to a store-wide beverage network, one is for a serial 
communication to an operator panel, and one is for the high speed input 
port scanner, one connector for a carbonation testing unit (12 pins: 5V, 
temp and pressure analog signals, solenoid and motor enables, 24 VDC and 
ground), and two for power to the board (one with 6 pins, +5V, +12V, VSS, 
AVSS, -12V, and Earth, one with 4 pins, 24 VAC hi, 24 VAC lo, +VM and 
-VM). The circuit can be described by tracing the inputs and outputs from 
the processor through five ports as well as a high speed input processor 
through five ports as well as a high speed input and high speed output. 
The ports are utilized as follows: 
Port 0: Temperature inputs from the selected flavor and water as a drink is 
being poured, the in-position and home photo sensor signal from the 
adjuster mechanism, and the interrupt signal from the communication. 
Port 1: Port 1 is not used. 
Port 2: Receives and transmits serial data; 
Port 3 and 4: Address data busses for the 27512 64K EPROM and the 81C78A-45 
8K RAM access; 
High Speed Input: Receives the selected flavor and water flowmeter pulses, 
the rotation detector for the adjuster drive chain, and the scan feature. 
High Speed Output: Delivers the stepper motor pulses. 
Serial data is transmitted to a 74HC594 which generates a four bit flavor 
select code, three bits sent to an ADG507 multiplexer to select the flavor 
flowmeter to be connected to the input, one bit sent to an ADG212 
multiplexer to select between water and soda flowmeters. Other serial data 
sent to this IC includes enables for the drivers for the adjuster 
solenoid. 
FIGS. 13-16 show a preferred embodiment of the present invention FIGS. 
13-16 show a flow control adjuster 200 that can be used in the dispenser 
10 in place of the flow control adjuster 38 described above. 
The adjuster 200 includes the flow control sprocket wheel 40 connected 
through the shaft 41 to each of the flow controls 36, and also includes an 
actuator 202 for controllably rotating a selected one of the sprocket 
wheels 40. 
The actuator 202 includes a plurality of linear gear racks 204, one for 
each sprocket wheel, positioning means 206 for moving a selected one of 
the gear racks 204 into mating contact with its respective flow control 
sprocket, and drive means 208 for moving the selected gear rack and in 
turn the flow control sprocket, a desired amount. 
The gear racks 204 are mounted in circumferentially and longitudinally 
different locations along a multi-rack adjusting shaft 210 mounted for 
rotation in a bracket 212. The shaft 210 is rotated the desired amount to 
position a selected gear rack in contact with a selected flow control 
sprocket by a selector means 14 including a solenoid 216, a ratchet arm 
218, and a shaft positioning gear 219. Each actuation of the solenoid 216 
turns the shaft 210 one position. 
After the selected gear rack is in contact with the selected flow control 
sprocket, the gear rack 204 is moved in an eccentric manner to rotate the 
flow control sprocket the desired amount by the drive means 208. The drive 
means 208 includes a motor 220 and a drive chain 222 connected to an 
eccentric mechanism 223, which includes sprockets 225 for turning two 
shafts 224 and 226. Each shaft is connected in turn to an eccentric shaft 
228 and 230 mounted for rotation in eccentric blocks 232 and 234. The 
blocks are attached to the bracket 212 that holds the shaft 210, to cause 
eccentric and reciprocating movement thereof such that the selected gear 
rack moves in an eccentric path. When the motor 220 turns in one 
direction, the selected gear rack moves in one direction (such as to the 
left in FIGS. 16C and D) so as to rotate the flow control sprocket and 
when it moves in the other direction (such as to the right in FIGS. 16A 
and B) it is moving out of contact with the flow control sprocket. When 
the motor 220 turns in the opposite direction, the opposite is true. 
The adjuster 200 remains at the home position until an adjustment is 
needed. Home is recognized by the use of a photosensor 240 that reflects 
off a flat section 242 of the multi-rack adjusting shaft 210. Home 
position is also the position required for adjusting the leftmost flow 
control. When an adjustment is needed on one of the other flow controls, 
the following occurs. 
The solenoid 216 actuates "x" times, causing the multi-rack adjusting shaft 
210 to rotate such that the piece of gear rack for flow control "x+1" is 
in the downmost position. The solenoid actuation causes the ratchet arm 
218 to grab the positioning gear 219 and pull the shaft 210 around. The 
gear 219 has a detent 244 to lock the shaft 210 in position. Various 
detents can be used, however, the preferred one is a ball held in a tube 
and spring biased against the gear 219. The shaft 210 only rotates in one 
direction (counterclockwise as viewed in FIG. 15). There is a position 
sensor 246 on the other end of the shaft 210 to ensure that each time the 
solenoid 216 is actuated, the shaft 210 actually moves. The position 
sensor 246 includes an encoder 248 that alternates dark and light to be 
sensed each time the solenoid 216 is actuated (i.e. position 2 light, 
position 3 dark, position 4 light, etc). 
Once the shaft 210 is properly positioned, the motor 220 (which can be a 
stepper motor or a simple bi-directional dc motor) is powered and the 
drive chain 222 moves the eccentric mechanism 223 via drive sprockets 225 
that causes the multi-rack adjusting shaft 210 and all of the associated 
bracket and hardware to move in an eccentric motion. The bottom part of 
this motion causes the selected gear rack 204 to come into mating contact 
with the selected flow control gear sprocket 40 and moves the sprocket one 
tooth either clockwise or counterclockwise, depending on the motor 
direction. An eccentric rotation sensor 250 consists of an encoder 252 
with a single slot that permits a light sensor 254 to detect a single 
point of the complete rotation (in the current design this senses the 
uppermost position of the eccentric rotation). The motor 220 would remain 
energized until the rotation sensor 250 "sees" the number of rotations 
corresponding to the magnitude of adjustment that is desired. 
When the adjustment is completed, the solenoid 216 energizes until the 
racked shaft 210 is back at the home position. 
The adjuster 200 attaches to the valve 142 at only two locations, by means 
of two attachment screws 256 with relief springs 258. The purpose of the 
springs 258 is to allow play in the eccentric motion in case the rack 
piece does not engage cleanly with the gear sprocket of the flow control. 
In the case when the two meet tooth to tooth, the spring would allow the 
rack to ride up until the eccentric path brings the rack around enough to 
drop down and engage. 
Each flow control is equipped with a gear sprocket as with the previously 
described design. A sprocket aligning rack is used to keep the sprockets 
in a single line. 
This embodiment allows much more access to the valve components for 
maintenance. Tolerances are less important to the operation of this 
adjuster mechanism 200. Another feature of this embodiment is the exacting 
adjustment procedure. Every time the eccentric goes through one complete 
motion, the flow control is moved exactly one tooth. Further, this 
embodiment has fewer pieces, is easier to assemble and will be less 
expensive than the previously described embodiment. 
While the preferred embodiment of this invention has been described above 
in detail, it is to be understood that variations and modifications can be 
made therein without departing from the spirit and scope of the present 
invention. For example, it is noted that a separate stepper motor can be 
used with each of a plurality of flow controls, rather than using a single 
stepper motor for a plurality of flow controls.