GB2190494A - Automatic control system for filling beverage containers - Google Patents

Abstract

An automatic, ultrasonic system for controlling the filling of different sizes of beverage containers 14, 16 which may or may not contain various quantities of ice, includes a transducer assembly 20 and a control module 26, both preferably connected to a beverage dispenser valve assembly 12. The transducer assembly includes a pair of piezo-electric crystals for separately transmitting and receiving ultrasonic wave energy from the grate 18, the cup lip, the top of any ice in the cup, and the rising liquid level. The control module includes a microcomputer and associated circuitry. The crystals of the transducer assembly include plastics lenses attached to their respective bottom surfaces, for both coupling the crystals to air and for lensing the crystals, e.g. for producing a shaped beam. <IMAGE>

Description

GB 2 190 494 A 1

SPECIFICATION

Automatic control system forfilling beverage containers Fieldof the invention 5

This invention relates to beverage dispensing and more particularly to an ultrasonic system for automatic ally controlling the fil I ing of beverage containers, such as with post- mix carbonated soft drinks.

Description of thepriorart

Heretofore, attempts have been madeto provide apparatusto automatically fill beverage containers,such 10 as cups, in responsetothe proper positioning of a cup under a nozzle of a dispensing valve assembly of a beverage dispenser. Such apparatus usedJor example, liquid level detectors such as either conductive or capacitive electrical probesto measurethe liquid level.

It is also known to measure various liquid leveiswithin containers using ultrasonic energy and associated circuitry. 15 Summary of the invention

According tothe invention there is provided an apparatusfor automatically filling a containerwith a bever agecomprising:

(a) ultrasonic energy transducer means fortransmitting ultrasonic energy down toward a container sup- 20 porting surface located below a beverage dispensing nozzle and for receiving ultrasonic energy reflected backup from the direction of said surface and for generating corresponding signals; (b) control circuit means for using said generated signals for detecting the presence of a container placed on said surface and below said nozzle; (c) said control circuit means including means for controlling the filling of a container on said surface with 25 beverage from said nozzle; and (d) said transducer means including at least one crystal having a plastic lens attached to a bottom surface thereof for both coupling the crystal to air and for lensing the crystal.

Viewed from another aspect, the invention provides a method of automatically filling a containerwith a beverage, comprising the steps of: 30 (a) transmitting ultrasonic energy down toward a containersupport surface located below a beverage dispensing nozzle from an ultrasonic transmitter and receiving ultrasonic energy, with an ultrasonic receiver, reflected backup from the direction of said surface and generating corresponding signals; (b) detecting from said signals the presence of a container placed on said surface and below said nozzle; (c) controlling the filling of said container with beverage from said nozzle; and 35 (d) using a crystal for at least one of said transmitter and receiver and attaching a plastic lens to a bottom surface of said crystal to both couple the crystal to air and to lensthe crystal.

The preferred embodiment comprises an automatic system for controlling the filling of different sizes of beverage containers or cups, which cups may contain various quantities of ice, with a beverage which mayor may notfoam during filling. The system includes a transducer assembly and a control module, both prefer- 40 ably connected to a beverage dispenser valve asseffi bly. The transducer assembly is mounted adjacent to the nozzle and uses a first crystal to transmit ultrasonic energy (ultrasound wave energy) and a second crystal to receive reflected ultrasonic energy. Both crystals have lenses for providing coupling of the beam between the crystal and the air, and for either producing a shaped beam (the transmitter crystal) or for receiving abeam from a defined area (the receiver crystal). The control module includes a microcomputer and associated 45 circuitry for controlling the f il ling operation, i ncludi ng determining that a cup is present below the nozzle of the valve assembly, determining thatthe cup does not have too much ice, filling the cup, waiting for any foaming to subside, topping off the cup to completelyfill it, and producing a signal to an operatorthatthe filling is completed.

It is a feature of the invention to lens the crystals using ABS or polycarbonate plastic. 50 It is a furtherfeature to provide such a system that employs signals received from the grate, the cup lip, and the liquid level in the cup.

It is anotherfeature to provide a high resolution ultrasonicfilling system in which the container and liquid level are in air and are very close to the crystals.

It is anotherfeature to provide such an ultrasonic system in which the receiver gain is maintained ata 55 constant gain during each transmission period forthe receiver crystal, butthe detection level or scheme is changed; in particularthe detection scheme is turned down very low until the transmitted beam is about one-half inch (1.27 cm) belowthe nozzle, and then the detection scheme is turned on at a constant rampto compensate for signal loss.

It is anotherfeature of the present invention to provide an ultrasonic system for automatically controlling 60 the filling of a beverage cup, which system: (1) uses a frequency of about 400 KHz, (2) looks at the leading edge of the reflected ultrasonic energy pulses rather than at the trailing edge, (3) makes the cup lip during certain routines, (4) lenses the transducer, (5) uses a lens material that both shapes the ultrasonic beam and also couples itto the air, (6) uses a timed fill forthe initial fill because of cup vibration and therefore lip vibration, (7) uses a low gain to seethe liquid level (which is abetter reflector than the lip) but not the lip 65 2 GB 2 190 494 A 2 during certain parts of the routine, (8) looks abovethe lip (the LGRATE subroutine) and shuts off thefilling if a signal abovethe lip (showing over-filling) is received, and (9) measures the filling time and shuts offthefilling ifthefill timeexceeds a maximum time period (to prevent continued filling of a cupwith a hole in itJor example.

Itis anotherfeature of the present invention to providea system foruse on adjacent beverage dispensing 5 valve assemblies to automatically control thefilling of beverage cups from such valve assemblies without interference therebetween.

It is a stil 1 f urther feature of the present invention to a] low placement of ultrasonically control led valve assemblies in close proximity to each otherwithout interference therebetween.

It is a furtherfeature of this invention to prevent unwanted interference f rom adjacent ultrasonical ly con- 10 trolled valve assemblies by synchronizing the operation of adjacent valve assemblies to different half cycles of the a.c. power supply.

Brief description of the drawings

Certain examples of the invention will now be described with referenceto the accompanying drawings 15 wherein like reference numerals referto like elements and wherein:

Figure 1 is a perspective view of a beverage dispenser having fourvalve assemblies each using the auto maticfilling system of the present invention; Figure2 is a perspective viewof one of thevalve assemblies of Figure 1; Figure3is a cross-sectional side view of thetransducer assembly shown in Figure2; 20 Figures4A and4Bare a master block diagram of the automatic control system of one embodimentofthe present invention; Figure 5 is a microprocessor block diag ram; Figure 6 is a schematic circuit diag ram of part of the receiver subassembly including the receiver, the receiverfront end, and the D/A gain reduction of Figure 4; 25 Figure 7is a schematic circuit diagram of another part of the receiver subassembly including the detector threshold comparator and the time varying detection generator of Figure 4; Figure 8 is a schematic circuit diagram of the power supply and output switch of Figure 4; Figure 9 is a schematic circuit diagram of the transmitter subsystem of Figure 4; Figure 10 is a schematic circuit diagram of the frequency divider of Figure 4; 30 Figure 1 1A is a schematic circuit diagram of the dip switch of Figure 4, and Figure 11 B is a table showing howto set the switches fora desired ice level; Figure 12 is a schematic circuit diagram of the front panel module with the manual fill switch andthe over-ice and filling indicator lights; Figure 13 is an elevational view showing a nozzle, the transducer assembly, the grate, and a cup; 35 Figures 14-26 are flowcharts illustrating the main routine and the su b- routines of the software for operat ing the microcomputer 66 in the block diagram of Figure 4; Figure 27 is a perspective view of another embodiment of a valve assembly useful on the beverage dis penser of Figure 1; Figure28 is a cross-sectional side view of the transducer assembly shown in Figure 27; 40 Figure29 is a cross-sectional end view of the transducer assembly of Figure 28; Figure 30 is an exploded perspective view of the transducer assembly of Figure 28; Figures 3 1A and 3 18 are a master block diagram of the automatic control system of the preferred embodi ment of the present invention; Figure 32 is a microprocessor block diag ram; 45 Figure 33 is a schematic circuit diag ram of part of the receiver subassembly including the receiver, the receiver front end, and the D/A gain reduction of Fig u re 31.

Figure 34 is a schematic circuit diagram of another part of the receiver su bassem bly including the detector threshold comparator, the time varying detection generator, and the 60 Hz detector of Figu re 31; Figure 35 is a schematic circuit diagram of the power su pply and output switch of Figu re 31; 50 Figure 36 is a schematic circuit diagram of the tra nsmitter subsystem of Fig u re 31; Figure 37 is a schematic circuit diagram of the frequency divider of Figu re 31; Figure 38A is a schematic circuit diag ram of the dip switch of Figure 31 and Fig u re 38B is a table showing howto setthe switches for a desired ice level; Figure 39 is a schematic circuit diag ram of the front panel module with the manual fil 1 switch and the 55 over-ice and filling indicator 1 ights; and Figures 40-46are f low charts illustrating the main routine and the su broutines of the software for operating the microcomputer in the block diag ram of Figure 31.

Detailed description of the preferred embodiments 60

With reference nowto the drawings, a first embodiment of the present invention will first be described with reference to Figures 1-26, and then a second embodiment will be described with reference to Figures 27-46.

Figure 1 shows a post-mix beverage dispenser 10 having four identical beverage dispensing valve assemb lies 12, each of which has been modified to include the automaticfilling apparatus of one embodiment of the present invention in place of the usual cup actuated mechanical lever that normally extends below each valve 65 3 GB 2 190 494 A 3 assembly 12 for operating the two solenoids of the valve assembly (one being for syrup and one for carbona ted water). Each of the valve assemblies 12 is used for dispensing soft drink beverages (usually a different beverage from each valve assembly) into various sizes of cups 14 and 16, supported on a cup supporting surface or grate 18. One particular beverage dispenser 10 and one particular valve assembly 12 is shown, however, any valve assemblies and any beverage dispenser can be used. Beverage dispensers and beverage 5 dispensing valve assemblies, such as those shown at 10 and 12 respectively in Figure 1, are well-known and thus no detailed description thereof is needed.

With reference to Figures 1 and 2, the automatic f il ling apparatus of the first embodiment of the present invention includes a transducer assembly 20 located on the bottom surface 22 of the valve assembly 12 and behind the nozzle 24, and a control module 26 attached to the front of the valve assembly 12. 10 The transducer assembly 20 is best shown in Figure 3 and includes a plastic housing 28 in which is con tained a transmitter crystal 30 having a plastic lens 32, and a receiver crystal 34 having a plastic lens 36. The transmitter and receiver crystals are located inside of brass tubes 38 and 40, respectively. A pair of shielded cables 42 and 44 are connected by a clamp 46 to the housing 28. Each cable has a shield wire connected to a respective one of the brass tubes and also a pair of wires connected to a respective one of the crystals at 15 opposite locations thereon, as shown in Figure 3. Each of the crystals has a metal plating on each of its upper and lower surfaces. The wire connections to the crystals include a pair of 34 gauge wires soldered one each to one of the metal platings on the crystal and then in turn soldered to two 22 gauge wires in the cables 42 and 44. The cables 42 and 44 are about six inches (1 5.24cm) long and terminate in a single IVITA connector 48jor connection to the control module 26. All of the space within the housing 28 is filled with urethanefoam 50. 20 The crystals 30 and 34 are preferably PZT-4 ceramic crystals (a generic trade designation for a particular crystal material), which are a combination of lead titanate and lead zirconate. Each of the crystals 30 and 34 is attached to its respective lens 32 and 36 preferably by using about 1/2 drop of glue such as that sold underthe trademark Eastman 910. The plastic lens is preferably made of ABS, polycarbonate, acrylic or polystyrene plastic. 25 The plastic housing 28 has a pair of flanges (flange 52 is shown in Figure 2) each having a screw holefor attaching the transducer assembly 20 to the valve assembly 12.

The brass tubes 38 and 40 have the functions of electrically shielding or isolating the crystals, of sound isolating the crystals, and of mechanically holding the crystals (along with the urethane foam which is pour ed into a mold orfixture used to hold all of the elements of the assembly 20 in place, and which isthen 30 allowed to harden).

The selection of the most desirable frequencyto use was made as follows. Regarding the upper limit,the attenuation of ultrasonic sound in the air becomes too greatto use for more than a few inches atabove approximately 600 KHz. In addition, it was desired to avoid the 455 KHz broadcast band IFfrequency, and the 550 KHzto 1.65 MHz AM broadcast band. By staying awayfrom FCC assigned frequencies, and by using a 35 transmission that is nottoo strong in relation to radio stations, interference on radio receivers that are oper ated in close proximity to the automatic control system of the present invention is precluded.

Regarding the lower limit, because the beam pattern is constricted by the close proximity of othervalve assemblies, a 2 inch (5.08cm) spread at 14 inches (35.56cm) atthe 3db point was assumed forthe beam pattern. This 2 inch (5.08cm) spread yields an angle of approximately 8 degrees total. Due to the spacing 40 considerations, a 1/2 inch (1.27cm) diameter crystal was selected. A 400 KHz frequency was selected asthe preferred frequency. Other frequencies in the range of 200 KHz to 450 KHz could alternatively be used.

Regarding the beam shape, at 14 inches (35.56cm) the total maximum beam pattern needs to be less than 3 inches (7.62cm) wide atthe limits of detectability (-40 db) in the side to side direction, and approximately 3 inches (7.62cm) frontto back atthe -3 db points. The gain atthese points would need to be as flat as 45 reasonable. The crystal pattern was chosen empirically as the one giving the best level gain from frontto backwith the crystals 30 and 34 aligned from front to back between the nozzle 24 and the splash plate 25. The resulting overall gain pattern with a 3db gain at 12 inches (30.48cm) had a resulting spread sideways of 3.5 degrees, and a resulting spread frontto rear of 12 degrees.

To achieve the desired beam pattern, it was necessary to lens the crystals. A 2 inch (5.08cm) concave radius 50 produced the 8 degrees to 3.5 degrees narrowing from side to side, and a 4 inch (10.1 6cm) convex radius produced the 8 degree to 12 degrees spreading from frontto rear which formed a fan shaped beam pattern with an elongated footprint having a width of approximately 3/4 inch (1. 91 cm) and having a length of about 2 1/2 inches (6.35cm) at 3db gain and 12 inches (30.48cm) away from the transducer assembly 20. This beam shape footprint has its long dimension extending frontto back relative to the dispenser. 55 Coupling from the crystals 30 and 34 to the air was calculated as follows:

Characteristic impedance of PZT-4 is equal to 66 x 1 0E6 rayls (E=exponent throughout thefollowing description).

60 65 4 GB 2 190 494 A 4 Transmitted power is (Tp) (N2/N1) X Pc Tp = (N2/M)+1 5 N2=The characteristic impedance of air. N1 =The characteristic impedance of M-4.

Pc= Power output of crystal. 10 Tp=1 2.6 x 1OE-6for 1 watt in, or.001 26% goestothe air.

If a third material is introduced between the air and the material we getthefollowing equation:

4(N3/M) (N2/N3) X Pc Tp=((N3/M)+11) x ((N2/N3)+1) 15 4(N2/M) X Pc 20 ((N2/N1)+1)+(N2/N3)+(N3/N1) Mostmaterialsof interest forthe third material have characteristic impedances between. 1 x 10E6to 10 x 1 0E6 rayls.

25 For.1 X 10E6,Tp=25 x 1OE-6 For10 X 10E6,Tp= 22 X 1OE-6 Thus, for any lossless material used as a coupling to air with a characteristic impedance between. 1 X10E6 to 10 X 1 0E6 rayls, the resulting input power is at least doubled and the energy transmitted to the air varies by 30 only 10%. The preferred lens material is one of the plastics such as acrylic or ABS. The lens should:

(1) be a plasticfor production, (2) have a l/i'(1.27cm) diameter and be approximately.08"(0.20cm) thick, (3) have a concave radius of Z' (5.08cm) in one axis and a convex radius of 4"(10.1 6cm) in the other axis, and 35 (4) be cemented to the crystal facewith about 1/2 drop of glue (preferably that sold under the trademark Eastman 910, or equivalent).

Regarding the lens mount, to diminish acoustic coupling between the receiver and transmitter,the lenses are mounted in polyurethane foam. A brass tube surrounds each crystal and its innerfoam mountwhich provides electrical shielding and is soldered to the shield of the cable wiring to the crystals. The crystals are 40 leftfloating, i.e., both electrodes are at a potential not referenced to ground. This gives greater electrical isolation in the receiversince it does not pick up ground referenced noise. The brass tubes are held in place bythe polyurethane foam to the desired package shape. The lenses protrude from the bottom surfacefoam package.

Regarding the crystal shape and material, the transmitter crystal is preferably 1/2" (1.27cm) OD x.20W' 45 (0.51 cm) for a series resonance of 400 KHz. M-4 material was chosen forthe crystals 30 and 34 as the best compromise in strength, efficiency, and ease of workability. The receiver crystal is preferably 1/2" (1.27cm)OD X.1 90"(0.48cm) for a parallel resonance of 400 KHz, and is also made of M-4 material.

Regarding the electrical wiring, a twisted shielded pair of 22 gauge stranded wire is used. The wire shield- ing is soldered to the brass tubes 38 and 40. The brass tubes are isolated from each other electrically. A pair of 50 34 gauge solid wires is soldered across the metal plated crystal faces and is then soldered to the 22 gauge lead wires. All wiring is foamed in place. The black wire of the twisted pair is attached to the outside crystal face which is marked with a small dot.

GB 2 190 494 A 5 Thecontrol module26 houses the control circuit board to which the crystals 30 and 34 are connected bythe cables42 and 44 and the connector 48. Figures 4A and 413 together provided a master block diagram ofthe control circuit 60. The control circuitwill now be described with referenceto Figures4-12.

The receiver transducer 62 (Figures 4,5, and 6) isa400 Khz, 1/2 inch (1. 27cm) diameter parallel resonant piezo-electric crystal 34made of PZT-4 material. The crystal iscoupledtotheairby meansof a plasticlens36 5 which isshapedto receivethe beam pattern. The transducer assembly 20 incorporatesa brasstube 40 that is 5/8inch (1.59cm) in diameterand is used for electrical isolation. The crystal 34is mounted such that itis centered in thetube with the lens 36 exposed atone end of the tube. The tube assembly is foamed with polyurethane for acoustic isolation.

The receiversection 64 (Figures 4,5 and 6) hasatotal gain of 96db and iscomprised of twoprotective 10 diodes 1 10and 112andtwo MC1350P 1Famplifiers 114and 116 that are interconnected through atuned transformer 1 18with another tuned transformer 120 to interconnect the second amplifier 1 16tothedetector 68. These amplifiers 114and 116 have provisions for gain controlfrom Pin 5and are used in this application bythe microcomputer 66.

The detector circuit 68 (Figures 4,5 and 7) changesthe400 Khzfromthe receiver64to a DCAnalogsignal. 15 This detector is special inthatitcan not only detect the envelope of the pulse butsince itisa DCcoupled detector, ithas no offset shift due to pulse width variations. Byhaving a balanced detector system, the temperature drift is very low.

The receivergain reduction 70 (Figures 4,5, and 6) iscomprised offive resistors that form a binaryweigh ted currentsinking "DtoA" converter that is driven bythe microcomputer66, which allows forthirty-two 20 stages of gain level control.

Thethreshold comparator72 (Figures 4,5, and 7) is comprised of an LM393N comparator 122 and is used in conjunction with thetime varying detection to convertthe analog receiversignal to a digital signal which is then fed to the microcomputer 66. Within this circuit is a meansfor adjusting the slope of thetimevarying detector using a 100K potentiometerand a means of adjusting thethreshold detector using a 500 ohm pot- 25 entiometer 125.

The time varying detection generator 74 (Figures 4,5, and 7) uses the gate signal that the microcomputer66 sends to the transmitter, and charges a 15 Nanofarad capacitor 124to two volts, which sets the peak level of the time varying detector wave form. This circuit is comprised of a 2N4126 switching transistor 126 and the power supplyto supportthat circuit. 30 The modulator 76 (Figures 4,5, and 9) is comprised of a 12 volt Zener diode 128 and two transistors 130 and 132 that perform an (Anding) function forthe transmitter gate signal (T) and the 400 KHz signal from the oscillator. This (Anded) signal is then level shifted through the 12 volt Zener diode 128 and the 2N4402 transistor 132 to the gate of the final amplifier 78.

The final amplifier 78 (Figures 4,5, and 9) is comprised of a BUZ-71 A MOS-FET 134, a resistor 136 and a 35 transformer 138. The resistor discharges the gate source capacitor of the MOS-FET 134. The MOS-FET 134 switches the output transformer 138 to the minus 20 volt supply in response to the gate drive signal. The transformer 138 steps the voltage up to the transmitting crystal 30 to approximately 2000 volts.

The transmit transducer 80 (Figures 4,5, and 9) is comprised of a 400 KHz 1/2 inch (1.27cm) diameterseries resonant piezo-electric crystal 30 made of PZT-4 material much the same as the receiver crystal 34 with the 40 exception of the thickness. The crystal 30 is coupled to the air by means of a plastic lens 32 which is also shaped to form the beam pattern. The assembly of the transmit transducer 80 is exactlythe same as forthe receiver as described above.

The microcomputer 66 (Figures 4 and 5) is a General Instruments Pic-1 654 and contains the intelligence and control functions of the entire system. It communicates to the rest of the system through twelve 1/0 pins. 45 It also contains the oscillator circuit, the master clear circuit, and the real time clock counter input.

The crystal 82 (Figures 4 and 5) and components of the 4 MHz crystal comprises passive componentsthat form the feedback networkforthe oscillator in the Pic-1 654.

The power-on reset circuit 84 (Figures 4 and 5) forms a 10 millisecond reset pulseto the microcomputer66 at POWER-ON that allows the 4 MHz oscillator crystal 82 to start and the microcomputer 66 to become 50 initialized.

A divide byten counter 86 (Figures 4,5, and 10) converts the 4 MHz computer clockto a 400 KHzsquare wave signal to operate the transmitter.

The divide bythree counter 88 (Figures 4,5 and 10) converts the 400 KHz signal to a 133 KHz signal that is applied to the microcomputer 66 as the real time clock counter input. Numberthirteen and numberfourteen 55 are encompassed within the same]C (74HC390) divider chip which has a divide byten and a divide bythree circuit.

The front panel module 90 (Figures 4,5, and 12) consists of two LED indicators 92 and 94. One is an "Over-lce/Cup Remove" (Figures 4,5, and 12) red indicator 92 and the other is a green "Fill ', LED 94, indica ting thatthe cup can be filled or is being f illed. This indicator 94 remains "on" steady when a cup is okuntil 60 filling starts. In the everitthat there is too much ice in the cup, orthatthe cup is not recognized as a cup,the red indicator light 92 will flash on and off.

There is a programming dip switch 96 (Figures 4,5, and 1 1A) comprising five individual switches ac cessible by removing a cover (not shown) on the lower rear surface of the control module 26. One switch is used to select between a normal flow or a flast flow valve assembly, depending upon which type of valve 65 6 GB 2 190 494 A 6 assemblythe automatic control system is being attached to. Another switch is used for selecting a foamy or flat product such as water. The other three switches are used for selecting ice level or test position. Thetest position is used for alignment of the receiver during manufacturing and has no field use. The binary output of the three ice level switches allows for seven ice level selections from 1/8 cup to 718thscu p, as illustrated in Figure 11 B. 5 The multiplexer circuit 98 (Figures 4 and 5) aliowsthe microcomputer 66 to read eitherthe dip switchesor to setthe gain of the receiveras necessary. It is comprised of five signal diodes.

The powersupply 100 (Figures 4,5, and 8) uses 24voltsAWrom the 50 VACtransformer (not shown) inthe dispenser 10. The present control system consumes lessthan 2volt-amps at 24volts AC. The 24volts AC is rectified and filtered to form a minus 20volt DC supply and a plus 25volt DC supply. The minus 20 voltsupply 10 is regulated with a Zenerdiode and supplies powerto thetransmitter. The plus 25volt supply is unregulated but has a 39 voltZener diode used as surge protection.The 25volt DC supply is regulated down to 15voltsfor the receiver subsystem by a 78L1 5 three terminal regulator 140. An MPS- A42 transistor 142 is used as a fly-backoscillatorto providethe plusfivevolts needed to operatethe computer circuitry. The 4.3voltZener diode 144 connected between the plusfivevolt supply and the base of a 2N4124 transistor 146 serveto 15 regulate the f ly-back oscillator.

The outputswitch 104 (Figures4,5, and 8) forthetwo solenoids of thevalve assembly 12 is operatedfrom eitherthe microcomputer66 orthe mutual push button 102 on thefrontof the control module 26. The resistor diode network coupiesthe microcomputer66 and the manual switch 102to the base of a 2N4124transistor 148which then turns the outputtriac 149 on or offwhich then turns thetwo solenoids in the valve assembly 20 12 on oroff.

The softwarewill now be described with referenceto Figures 13through 26. Figure 13 is a side elevation viewshowing thetransducer assembly 20,the lenses 32 and 36,the nozzle 24of the beverage dispenservalve assembly 12,the control module 26,the splash plate 25,the grate 18 and a cup 16 having a cup lip 17, a cup bottom 19, and a top level 21 of ice in the cup. 25 The software includesfour (4) major routines which are labeled Initialization Routine (INIT), Cup Detection (CUPDET), Fill Routine (FILL), and Cup Removal Routine (CUPREM).

The software also includes five (5) subroutines that are defined asTime Delay (WAIT), Absolute Value of the Difference of Two Numbers (DIFF), Grate/Overflow Detector (LGRATE), Transmit (T131)QJ13DW, and TLD as described below), and Receive (REC). 30 TheTransmitter Subroutine sets the variables forthe receiver routine and outputs a 25 microsecond pulse (10 cycles at400 KHzwhich occupies.1 'I (0.25cm) air space) during which time the transmitter is active. The selection of receiver variables is made through three different entry points (or surfaces off which thetrans mitted beam reflects): T13l3Q (Transmit Bottom Detector), T13DW (Transmit Bottom Detectorwith window), and TLD (Transmit Lip Detector). 35 The receiver has 32 steps of gain control led by the software. The gain issetto min imu m from the sta rt of transmitto approximately 1.W (3.30cm) target distance time (180 microseconds). At that time the gain is set equal to the gain variable set u p in the entry point routines. For TLD, the gain is always set to maxim urn. For T13DQ and TB13W, the gain is determined by the calling routine. 1 n T13l3Q and TLD, the dista nce of thefirst echo detected is captured for processing. In T13DW, a lip masking window is enabled which ignores any 40 echoes closer than the lip distance +.25" (0.64cm). This allows a hig her gain to be used to look at 1 iquid level rising inside the cup. Under al 1 entry poi nts, 5 transmissions and receptions are made with the echo distances stored in RAM. The processing algorith m looks fortwo samples that correlate within. 1 " (0.25cm) for TLD, or 1 12.54cm) forT13DQ and T13DW The average of the two distances is used as the echo distance. A 2 milli second delay is incorporated before each transmit to allow previous multiple ref lections to decay. 45 WAIT is a programmable delay subroutine that returns to the calling routine immediately if the manual push button is pressed. It has a maximum delay of 1 second.

DIFF is a subroutinethat calculates the absolute value of the difference of two numbers.

LGRATE is the Grate/Overflow detector subroutine and is used during the FILL routine. It uses TLD to detect with maximum gain and no window. If the subroutine detects an echo distance less than the lip distance 50 minusX' (0.25cm), the overflowflag is set before returning. If the subroutine detects an echo distancewithin 25" (0.64cm) of the grate distance, the cup removal flag is set before returning.

[NIT is used when the microcomputer is initialized by the "Master Clear" (hardware). During power up,the first instruction processed is at location 777 octal. This instruction, "GOTO IN W' commands the computerto begin executing this routine, which comprises the following: (1) the RAM is cleared; (2) wait 1 second for 55 powerto stabilize; (3) run the diagnostic routine if enabled; (4) use TLD to lookwith maximum gain and no windowfor an echo distance between 7' (1 7.78cm) and 1X (33.02cm); (5) if it does not detect an echo within this range, the "Over Ice" indicator on the front panel flashes; (6) if it does detect an echo distance within 7' (1 7.78cm) to 1W (33.02cm), the distance is stored in RAM asthe Grate distance and the program continues at CUPDET. 60 CUPDET is the Cup Detection routine. This routine collects data using TLD and accepts a cup using the following procedure:

A. The manual fill switch on the front panel is monitored continuously to assure proper operation. If the manual switch is pressed, the computer begins the Cup Removal routine immediately.

B. Astable lip distance must be established more than X (7.62cm) from the grate. Astable lip distance is 65 7 GB 2 190 494 A 7 defined as 5consecutive echo distancesfrom TLD separated by6 milliseconds that correlate within.2" (0.51cm). This corresponds to the cup lip being stablefor 130 milliseconds.

C. A cup bottom or ice level must be discerned that is more than. 1 " (0. 25cm) above the grate and more than.25" (0.64cm) below the lip. This is accomplished by using TBDW and varying the gain as follows:

With minimum gain, obtain an echo distance using TBDW. If the echo distance is not more than.V(0.25cm) 5 closer than the grate, then the gain is increased 1 step and another sample is taken. If the gain reaches the maximum, the Over-ice indicatorflashes and the Cup Detection routine begins again.

D. The ice/bottom height is calculated from the last distance obtained as outlined in (c) above and the grate, and then stored as the actual ice height. The cup height is calculated from the lip distance and the grate.

The cup height is divided by8 and the quotient is multiplied bythe 3 bit binary number input as selected on 10 the ice level programming switches. This allowable ice height is compared with the actual ice height. If the actual ice height is greaterthan allowed by the switch selection, the Over-ice indicatorflashes and the Cup Detection routine begins again. If the actual ice height is less than the amount selected by the switch, the FILL routine begins.

The FILL routine controlsthe completefilling and top off operation. The routine limitsthe solenoid oper- 15 ation to a maximum of 3 On/Off cycles. After each of thefirst 2 cycles, the routine waitsforthefoam to settle before starting the next cycle. Afterthefoam is settled and the cup is within 7/20" (0.89cm) of being full,the Cup Removal routine begins. If the manual switch is pressed at anytime during the FILL routine, the Cup Removal routine begins immediately. Each of the cycles has a maximum solenoid on timewhich if exceeded causesthe Cup Removal routine to being. 20 Adetailed description of the FILL routinefollows:

A. Before the valve assembly 12 solenoids are actuated, several checks and corrections are made. The gain is initially set at 11/16 of maximum gain. If the Lip Distance is less than 4'(1 0.1 6cm), the gain is adjusted with the empirically derived equation:

Gain = Gain - 1/8 (4!'(10.1 6cm) - lip distance). 25 If the Lip Distance is less than 4"(10.1 6cm), the lip Distance is adjusted with the empirically derived equa tion:

Lip Distance = Lip Distance - 118 (4'(1 0.1 6cm) - Lip Distance) If the Lip Distance is less than.1" (0.25cm), the Lip Distance is settoX' (0.25cm) to allow the cup overflowto function properly. 30 The Time Constant for this particular cup height is calculated with the equation:

Time Constant = cup height - 7 (5.08cm).

Thistime constant is used in each of thethree cycles to provide a maximum "Solenoids On" time prop ortional to the cup height.

B. The gain must be adjusted such thatthe fluid level is detected and the lip is not during the period when 35 the cup vibrates such as atthe beginning of a FILL. To accomplish this a period of time proportional to cup height is programmed to allowfilling to start and gain enough weightto minimize cup vibration and adjust gain as necessary. During this time period the routine uses T13DQto check if the echo distance is within.75" (1.91 cm) of the Lip Distance. If it is, the gain is reduced one step. If the gain reaches minimum, the cup removal routine begins. If the cup is removed during this period, the solenoids will notturn off becausethe 40 Grate/Overflow detector subroutine is not called during the period dueto trying to get as many samples as possible to adjust the gain. At the end of the period, the solenoids stay on.

C. A second maximum time period begins that is also proportional to the cup height. During thistime period, the routine uses T13DWto monitorthe liquid level and turns the solenoids off when the liquid level is within.5" (1.27cm) of the Lip Distance. The Grate/Overflow detector subroutine checks to see if the cup has 45 been removed or if TBDW has missed the liquid level rising and an overflow is imminent. If the cup is missing, the cup removal routine begins. If there is an overflow indicated, the solenoids are turned off.

D. A 5 second pause begins atthis time to allowthe foam to settle.25" (0. 64cm) below the cup lip. The Grate/Overf low subroutine checks once each second to ascertain that a cup is still in place. If the cup is missing, the cup removal routine is started. 50 E. Afterthe 5 second pause, a minimum number of seconds forthe foam to subside is set at 16, and once a second, an echo distance is obtained with TBDQ. If 2 consecutive echo distances are within. 1 " (0.25cm) of each other, or if the period times out, the top off cycle begins. The Grate/Overf low detector subroutine checks once a second fora missing cup. Once a cup is found missing, the cup removal routine begins.

F. The top off cycle uses TBDQto determine if the liquid level is within 7/20" (0.89cm) of the lip. If this 55 condition exists, the solenoids are not turned on. If the echo distance is not within 7120" (0.89cm), the sole noids turn on until that condition is met.

G. A repeat of M", "E," and "F" now occurs to implementthe second top off cycle.

The cup removal routine (CUPREM) turns the fill indicator 92 off, the value assembly 12 solenoids off, and the Over-ice indicator 94 on. It uses TLD and waits for an echo distance within.25"(0.64cm) of the grate. When 60 this condition exists, anew grate distance is stored, the Over-ice indicator turns off, and the Cup Detection routine begins again.

As described above,the system of the present invention provides an ultrasonic method and apparatusfor controlling the automatic filling of beverage cups. The system can be used with any beverage, such ascoffee, tea, milk, fruitjuice, and carbonated soft drinks. The beverages can produce foam during filling or not. 65 8 GB 2 190 494 A 8 Different sized cups can be used and they can have icetherein.

The system can be used in conjunction with any known, standard beverage dispenser. In the case of carbonated soft drink dispensers, the transducer assembly and the control module of the present invention are located directly on the valve assembly. The cup actuated arm and the microswitch are removed from the standard valve assembly; the triac 149 in Figure 8 takes the place of the microswitch and simultaneously 5 turns the syrup solenoid and the carbonated water solenoid on and off.

The system of this invention is on and working wheneverthe powerto the dispenser is on. The power is often left on to the dispenserto maintain the refrigeration system on.

A brief overviewwill now be provided without reference to the details of the system, which have already been described above. 10 The system first obtains a grate signal and stores it in the RAM. The way it does this is to transmitfive 25 microsecond pulses (having a length in air of about 0.1 inch (0.25cm)), each spaced apart about 2 milli seconds. If two signals are not received that are the same within 0.1 inch (0.25cm), then this first set of pulses is discarded and a newset of five pulses is immediately (in abouttwo milliseconds) transmitted. If two signals are received and are within 0.1 inch (0.25cm), and if they are from a distance of from about 7 (17.78cm) to 13 15 inches (33.02cm), then the system decides that it is the grate distance and stores it in the RAM.

The system then goes to the cup detection routine. The same set of pulses is transmitted and is received at maximum sensitivity. To determine that a cup is present, the system has to see 5 consecutive echo distances, each separated by 6 milliseconds, that correlate to within 0.2 inch (0.51 cm). That is, 5 sets of pulses are transmitted with 6 milliseconds between each set. If at leasttwo signals are received from the first set of 5 20 pulses that are within 0.1 inch (0.25cm), then that will be one value (or one echo distance). After receiving 5 of those in a rowwithin 0.2 inch (0.51 cm), the system knows that a cup lip (or something otherthan the grate) is present.

The system then goes to the next routine. In this routine the system looks for something greaterthan 0.1 inch (0.25cm) above the grate and greaterthan 0.25 inch (0.64cm) below the lip, that is, eitherthe cup bottom 25 or ice. If itfinds this, it concludes thatthe something present is a cup (ratherthan just a hand, forexample).

When the ice or bottom is obtained, it is stored temporarily. The cup height is then calculated andthe ice height is then calculated. It is then calculated whether or notthe cup has too much ice. If it does not,the system goesto the FILL routine. This routine is somewhat complex.

In the FILL routine there arefourfilling periods. Afirst period or initial fill that is not monitored but which is 30 set as a time function based on cup height. Itwill fill to about 1/3 cup under certain usual conditions. The system then switches automatically, without stopping the filling, to the second period in which the filling is monitored, and in which the filling is shut off when the liquid level rises to within 0.75 inch (1.91 cm) of the stored lip distance. The FILL routine then waits 5 seconds to allowfoam to subside (if the control module is setfor a foamy beverage). The monitoring continues waiting forthe foam to quit moving and when two 35 distances are received within 0.1 inch (0.25cm), then it calculates if the level is within 7/20 inch (0.89cm) of the lip. If it is not, filling is resumed and monitored until the level is within 7120 inch (0.89cm) of the lip. If it is within 7/20 inch (0.89cm), filling does not resume. The "top off" routine is then repeated after another 5 second pause.

Afterthe end of the FILL routine, the fill indicator light 92 isturned off, the solenoids are turned off, andthe 40 over-ice indicator light 94turns off.

A second (and preferred) embodiment of the present invention will now be described with referenceto Figures 27-46. An important difference between this preferred embodiment and that described above with referenceto Figures 1-26 is thatthe preferred embodiment is designed so that two or more beverage dispens- ing valves having the ultrasonic control system of the preferred embodiment can be located in close pro- 45 ximityto each other, such as by being adjacentvalves on a dispenser, without interference therebetween.

However, many otherfeatures of the two embodiments are identical.

Figure 27 shows a valve assembly 212, similarto valve assembly 12, that can be used as one or more of the valve assemblies on the dispenser 10 of Figure 1. The automatic filling apparatus of this embodiment of the present invention includes a transducer assembly 220 located on the bottom surface 222 of thevalve 50 assembly 212 and behind the nozzle 224, and a control module 226 attached to the front of the valve assembly 212.

Thetransducer assembly 220 is best shown in Figures 28-30 and includes a plastic housing 228 in which is contained a transmitter crystal 230 having a plastic lens 232, and a separate receiver crystal 234 having a plastic lens 236. The transmitter and receiver crystals are located inside of brass tubes 238 and 240, re- 55 spectively.

A pair of shielded cables 242 and 244 each consist of a shield wire connected to a respective one of the brasstubes 238 and 240 and also a pair of wires connected to a respective one of the crystals at opposite locations thereon, as shown in Figure 28. Each of the crystals has a metal plating on each of its upper and lower surfaces. The wire connections to the crystals are 28 gaugewire soldered directlyto the crystal plating. 60 The cables 242 and 244 are about nine inches long and terminate in a single IVITA connection (such as 48 in Figure 3), for connection to the control module 226. Substantially all of the space within the housing 228 is filled with urethanefoam 250.

The transmitter crystal 230 and the receiver crystal 234 are preferable PZT-5a ceramic crystals (a generic trade designation fora particular crystal material), which area combination of lead titanate and lead zirco65 9 GB 2 190 494 A 9 nate. Each ofthe crystals is attachedto its respective lens preferably byusing about 112 drop of gluesuch as thatsold underthe trademark Eastman 910. The plasticlens is preferablymade of ABS orpolycarbonate plastic.

The plastic housing 228 has a pairof flanges on each sidethereof, eachfiange having a screw holefor attaching the transducer assembly 220 to the valve assembly212. 5 The brasstubes 238 and 240 have the same function as described abovewith referenceto brasstubes38 and 40.As shown in Figures 28-30, the transducer assembly 220 includesthe plastic housing 228, a urethane foam filler250, a urethanefoam lid 400, a plastic cover 402, and the transmitter and receiver su bassemblies 420 and 422, respectively, slid into a pairof spaced-apart cylindrical cavities in thefoam filler250.

The transmitter subassembly 420 includes the transmitter crystal 230,the lens 232, a urethanefoam 10 thimble 424 and the brass tube 238. The receiver subassembly similarly includesthe receivercrystal 234,the lens236, a urethane foam thimble 426 andthe brasstube240.

The lenses 232 and 234areshaped asshown in Figures28 and 30with a squareflangeand a circular lipto receivethe crystal. The crystal is gluedtothe lens as described above. Thecrystal-lens unit isthen pushed inside the thimble and thetube is pushed overthethimble. The lens has a recess forthe wire connection to 15 the lowerfaceof the crystal andthethimbles havetwo grooves asshown in Figure 28forthetwowires connectedtothe crystal. No grooveis provided for the wire connected to the brasstube.

The housing 228 has a pairof thin flanges 408 and 410 and a pairof thickflanges412 and 414withscrew holesforuse in connecting the transducer assembly 220 to the dispensing valve 212. The thick flanges 412 and 414are usedto adjustthe position of the housing 220 andthus,the location of thetransmitted beam. 20 Asshown in Figure28,the lenses 232 and 236 are recessed intothe bottom of thefoam filler250to provide a baffle 251 there between. Also, the lowersidewalls 253 of thefiller250 extend downwardly belowthe lenses 232 and 234. The baffle 251 helps prevent ultrasonic energy passing directly from the transmitter to the receiver. The sidewalls 253 help prevent ultrasonic energy from being transmitted sideways to an adjacent valve. The foam absorbs the ultrasonic energy. 25 The selection of the most desirable frequency to use is also the same as described above with reference to the first embodiment.

Regarding the beam shape, at 14 inches (35.56cm), the total maximum beam pattern needs to be less than 3 inches (7.62cm) wide at the limits of detectabil ity (-40 db) in the side to side direction and approximately 3 inches (7.62cm) front to back with -3 db point in the front followed closely by the 0 db point and then tapering 30 off to -6 db atthe rear. The gain at a point nearthefront of the pattern (toward the nozzle) needs to be a maximum with the gain failing off smoothly by about 6 db as the pattern reaches the back point. The crystal pattern was chosen empirically as the one giving the best cup lip to ice (front) ratio with the crystals aligned from front to back between the nozzle 224 and the splash plate 25.

The resulting overall gain pattern at 12 inches (30.48cm) had a spread sideways of 3.5 degrees, and a 35 resulting spread froritto rear of 12 degrees.

To achievethe desired beam pattern, itwas necessaryto lensthe crystals. A 2 inch concave radius prod uced the 8 degreesto 3.5 degrees narrowing from side to side for both transmit and receiving crystals, a4 inch (10.1 6cm) convex radius produced the 80to 12'spreading from froritto rearforthe receivercrystal and a flat lenstoward the frontfor 1/2the crystal followed by a 3 inch (7.62cm) convex radius to the rearforthe 40 transmitter crystal which formed a fan-shaped beam pattern with an ' elongated footprint having a width of approximately 314 inch (1.91 cm) at -3 db and having a length of about 2 1/2 inches (6.35cm) with a brightspot about 1 inch (2.45cm) in from the front with -3 db atthe front and -6 db at the rear and 12 inches (30.48cm) awayfrom the transducer assembly 220. This beam-shape footprint has its long dimension extending front to back relative to the the dispenser. 45 Coupling from the crystals to the air was calculated in the same manner described above forthefirst embodiment.

One change in this second embodiment is that the lenses are inset into the bottom surface of thefoam package.

Regarding the crystal shape and material, the transmitter crystal is preferably 1/T' (1.27cm) OD X.20W' 50 (0.51 cm) for a series resonance of 400 KHz. M-5a material was chosen forthe crystals 230 and 234 asthe best compromise in strength, efficiency, low mechanical Q, and ease of workability. The receiver crystal is preferably 1/7' (1.27cm) OD x.190'1 (0.48cm) for a parallel resonance of 400 KHz, and is also made of M-5a material.

Regarding the electrical wiring, a twisted shielded pair of 28 gauge stranded wire is used and soldered 55 directlyto the plating on the crystal faces. The wire shielding is soldered to the brass tubes 238 and 240. The brass tubes are isolated from each other electrically. The blackwire of the twisted pair is attached tothe outside crystal face which is marked with a small dot.

The control module 226 houses the control circuit board to which the crystals are connected bythe cables 242 and 244 and the connector 248. Figures 31A and 31 B together provide a master block diagram of the 60 control circuit 260. The control circuitwill now be described with reference to Figures 31-39.

The receiver transducer 262 (Figures 31,32, and 33) is a 400 Khz, 1/2 inch (1.27cm) diameter parallel reso nant piezo-electric crystal coupled to the air by means of a plastic lens shaped to receive the beam pattern.

Thetransducer assembly 220 incorporates a brass tube 240 that is 518 inch (1.59cm) in diameter and is used for electrical isolation. The crystal is mounted such that it is centered in the tube with the lens 236 exposed at 65 GB 2 190 494 A 10 one end ofthetube.The polyurethane foam provides for acoustic isolation.

The receiversection 264 (Figures31,32 and 33) has atotal gain of 96 db and is comprised of two protective diodes310 and 312 andtwo MC1350P IF amplifiers 314 and 316thatare interconnected through atuned transformer 318 with anothertuned transformer 320 to i nterco n nect the second amplifier 316 to the detector 268. These amplifiers 314 and 316 have provisions for gain control from Pin 5 and are used in thisapplication 5 bythe microcomputer 266.

The detector circuit 268 (Figures31,32 and 33) changesthe400 Khzfrom the receiver264to a DCAnalog signal. This detectoris special in thatitcan not only detect the envelope of the pulse butsince it is a DC coupled detector, ithas no offset shift due to pulsewidth variations. By having a balanced detectorsystem, thetemperature driftisverylow. 10 The receivergain reduction circuit270 (Figures31,32, and 33) is comprised forfive resistors that form a binaryweighted currentsinking "D andA" converterthat is driven bythe microcomputer 266, which allows forthirty-two stages of gain level control.

The threshold comparator 272 (Figures 31,32, and 33) is comprised of an LM393N comparator322 and is used in conjunction with the time varying detection to convertthe analog receiver signal to a digital signal 15 which isthen fed to the microcomputer 266.

The time varying detection generator 274 (Figures 31,32 and 34) uses the manual /TVD signal from the microcomputer 266 and charges a 15 Nanofarad capacitor 324to two volts, which sets the peak level of the timevarying detector waveform. This circuit is compromised of a 2N4126 switching transistor326 and the power supplyto supportthat circuit. 601-1z detection is accomplished in the 60Hz detector shown in Figures 20 31,32 and 34. The incoming 60Hz, 24VAC power is sensed, afterfiltering, by 112 of the comparator LM393N 322 and the output shunts the TVD signal to ground which, because the detector 268 signal is biased above ground, forces the detector comparator output high for 112 of the 601-1z wave form. The microcomputer 266 senses this and uses the falling edge of the 60Hz signal from the detector comparatorto start its sequences and is thereby phase locked to the 60Hz -24VAC power system. Adjacent valve assemblies are separated in 25 time by reversing their 24VACwires 450 and 452 (see Figure 32) so that adjacent units synchronize to different 112 cycles of the 601-1z power supply and thereby do not interfere with each other. Alternatively, a switch can be provided having two positions labeled "A" and "B" to designate the two possible orientations of thewires 450 and 452. Thus, if one valve assembly has an "A" position, each immediately adjacentvalve assembly must have the switch on the "B" position. Units spaced more than one valve assembly apart are farenough 30 apart notto interfere with each other.

The modulator 276 (Figures 31,32, and 36) is comprised of a 12 volt Zener diode 328 and twotransistors 330 and 332 that per-form an (Anding) function for the transmitter gate signal (T) and the 400 KHz signal from the oscillator. This (Anded) signal is then level shifted through the 12 volt Zener diode 328 and the 2N4402 transistor 332 to the gate of the final amplifier 278. 35 The final amplifier 278 (Figures 31,32, and 36) is comprised of a IRF-523 MOS-FET334, a resistor 336 and a transformer338. The resistor discharges the gate-source capacitor of the MOS-FET 334. The MOS-FET334 switchesthe output transformer 338 to the minus 20 volt supply in response to the gate drive signal. The transformer338 steps the voltage up to the transmitting crystal 230 to approximately 2000 volts.

The transmittransducer 280 (Figures 31,32, and 36) is comprised of a 40OKHz 112 inch diameterseries 40 resonant piezo-electric crystal 230 made of PZT-5A material much the same as the receiver crystal with the exception of the thickness. The crystal 230 is coupled to the air by means of a plastic lens 232 which is also shaped to form the beam pattern. The assembly of the transmit transducer 280 is exactly the same as forthe receiver as described above.

The microcomputer 266 (Figures 31 and 32) is a General Instruments Pic-1 654 and contains the intelligence 45 and control functions of the entire system. it communicates to the rest of the system through twelve 1/0 pins.

It also contains the oscillator circuit, the master clear circuit, and the real time clock counter input.

The crystal 282 (Figures 31 and 32) and components of the 4 MHz crystal comprises passive components thatform thefeedback networkforthe oscillator in the Pic-1 654.

The power-on reset circuit 284 (Figures 31 and 32) forms a 10 millisecond reset pulse to the microcomputer 50 266 at POWER-ON that allows the 4 MHz oscillator crystal 282 to start and the microcomputer 266 to become initialized.

A divide byten counter 286 (Figures 31, 32, and 37) converts the 4 MHz computer clock to a 400 KHzsquare wave signal to operate the transmitter.

The divide bythree counter 288 (Figures 31, 32 and 37) converts the 400 KHz signal to a 133 KHz signal that 55 is applied tothe microcomputer 266 as the real time clock counter input. Numberthirteen and number four-teen are encompassed within the same]C (74HC390) divider chip which has a divide byten and a divide bythreecircuit.

The front panel module 290 (Figures 31,32, and 39) consists of two LED indicators 292 and 294. One is an "Over-lce/Cup Remove" (Figures 31,32, and 39) red indicator 292 and the other is a green "Fill" LED 294, 60 indicating thatthe cup can be filled or is being filled. This indicator 294 remains "on" steady when a cup is ok until filling ends. In the eventthatthere istoo much ice in the cup, the Over-lce/Cup Remove red indicatorwill light and stay lit until the cup is removed. If the cup is not recognized as a cup, due to mispositioning the green indicator light 294 will flash on and off.

There is a programming dip switch 296 (Figures 31,32 and 38A) comprising five individual switches ac- 65 GB 2 190 494 A 11 cessibie by removing a cover(notshown) onthe lower rearsurfaceof thecontrol module 226. Oneswitch is usedto select between a normal flow or a fastflow valve assembly, depending upon which typeofvalve assemblythe automatic control system is being attachedto. Anotherswitch is used for selecting afoamyor flatproductsuch aswater.The other three switches are used forselecting ice level ortest position. The test position is usedfor alignmentofthe receiverduring manufacturing and has nofield use.The binaryoutputof 5 thethree ice level switches allowsforseven ice level selectionsfrom 1/8cupto 7/8ths cup, as illustrated in Figure38B.

The multiplexer circuit 298 (Figures 31 and 32) allowsthe microcomputer 226 to read eitherthedip switches orto setthe gain of the receiveras necessary. It is comprised offivesignal diodes.

The powersupply300 (Figures 31,32, and 35) uses 24volts AC from the 24 VAC transformer (notshown) in 10 the dispenser 10.This 24VAC isfilteredto remove any highfrequency noisethat might interferwiththe system operation.The presentcontrol system consumes lessthan 2volt-amps at 24voltsAC. The 24voltsAC is rectified and filtered to form a minus 20voltDCsupply and a plus 25volt DCsupply. The minus 20volt supplyis regulated with a Zenerdiode and supplies power to the transmitter. The plus 25voltsupplyis unregulated but has a 39 volt Zener diode used as surge protection. The 25volt DC supplyis regulated down 15 to 15voltsforthe receiver subsystem by a 78L1 5 three terminal regulator340. An MPS-A06 transistor 342 is used as afly-backoscillatorto providethe plusfivevolts neededto operatethe computer circuitry. The4.3 volt Zener diode 344 connected betweenthe plus five volt supply andthe base of a 2N4124transistor346 serveto regulate the fly-back oscillator.

The outputswitch 304 (Figures31,32, and 35)forthetwo solenoids ofthevalve assembly212 isoperated 20 from eitherthe microcomputer 266 orthe manual push button 302 on thefrontof thecontrol module226.The resistor, opto-coupler network couples the microcomputer 266 to the Triac 349 which in turn energizesthe valve solenoids in thevalve 212when eitherthe microprocessor 266 orthe manual push button 302so requires.

Thesoftwarewill now be describedwith referenceto Figures 40 through 46. 25 Thesoftware inciudes4 major routineswhich are labeled Initialization Routine (INIT), Cup Detection (CUPDET), Fill Routine (FILL), and Cup Removal Routine (CUPREM).

The software also includes six subroutines that are defined as time delay (WAIT), absolute value of the difference of two numbers (DIFF), Grate/Overflow detector (LGRATE), Transmit/Receive, checkfortest mode (TSTCHQ and checkfor maximum value on time (TIMOUT). 30 The Transmitter/Receiver subroutine obtains a distance data by allowing thetransmitterto operate fora period of 25 microseconds (10 cycles at400 kHzwhich occupies.V (0.25cm) airspace) and then monitoring the receiver output for reflections. Two Transmit/Receive periods are contained in the time period of a single half cycle of the sinusoidal line inputvoltage. The synchronization permits transmission only during the positive half cyclewhich allowstwo valves to operate side by side without interference by reversing the line 35 inputwires on adjacent valves. Three different entry pointsto the subroutine select receiver options: TBD (Transmit Bottom Detector), TBDW (Transmit Bottom Detectorwith Window) and TLID (Transmit Lip Detec tor).

The receiver has 32 steps of gain controlled bythe software. The gain is setto minimum from the startof transmitto approximately.9" (2.29cm) target distancetime (180 microseconds). Atthattime,the gain is set 40 equal to the gain variable set up in the entry point routines. ForTLD, the gain is always setto maximum. For TBD and T13DW, the gain is determined bythe calling routine. In TBD and TLD,the distance of the firstecho detected is capturedfor processing. In T13DW, a lip masking window is enabled which ignores anyechoes closerthan the lip distance +3Y (0.89cm). This allows a higher gain to be used to lookat liquid level rising insidethe cup. Under all entry points, 2 transmissions, each separated bytwo milliseconds of receivetime 45 and two milliseconds of waiting for all reflections to cease. are made andthe received distances stored in RAM. The processing algorithm accepts the distances if they correlate within a.4" (1.02cm) and returnswith the mean value asthe correct distance. If thetwo distances do not correlate,then the routine waits onthe synchronization signal and takestwo newsamplesto correlate.

WAITis a programmable delay subroutine that returnstothe calling routine immediately if the manual 50 push button is pressed. It has a minimum delay of 3.5 msec, and a maximum delay of.9 seconds.

DIFF is a subroutinethat calculatesthe absolute value of the difference of two numbers.

LGRATE is Grate/Overflow detector subroutine used during the FILL routineto determine whether a cup has been removed or if foam or liquid has risen above the lip. The subroutine uses TLD to detectwith maximum gain and no window. If TLD returns with a distance of exactly 13. 7' (34.80cm),the distance is 55 rejected and TLD is called again. 13.7' (34.80cm) is the maximum distance allowed bythe receiver software and indicates no reflection was detected. If TLD returnswith a distance less than.25" (0.64cm), the overflow flag is immediately set. If TLD returns with a distance morethanY' (0. 25cm) closerthan the stored Lip Distance forthree consecutive callsto TLD, the overflowflag is set. If TLD returns a distance farther than.25" (0.64cm) abovethe stored GRATE valuefortwelve consecutive callsto TLD, the cup removed flag is set. If TLD 60 at anytime returns a distancethat does not meet any conditions above,the subroutine ends with no flagsset.

TSTCHK (Figure 44A) is a subroutinethat reads thefive position DIP (Dual Inline Package) switch.The switch positions are stored in the location in RAM labeled SWITCH. If the switches in positions 1, 2 and 3 are all offtheTestflag is set.

TIMOUT (Figure44B) is used wheneverthe solendid valve is turned on. The subroutine decrementsthe 65 12 GB 2 190 494 A 12 "Valve on Time" register and checks to see if the value of the Register is Zero. If it is greaterthan zero the subroutine ends. If the value of the register is zero, the routine enters a trap loop from which there is no exit exceptthrough a hardware reset. The trap loop turns the solenoid off and alternately flashes the red and green indicators.

INIT (Figure45A) is used when the microcomputer is initialized bythe "Master Clear" (hardware). During 5 power up,thefirst instruction processed is set at location 777 octal. This instruction "GOTO IN17' commands the computerto begin executing this routine, which comprises the following:

a. All RAM are cleared.

b. Wait 1 second for power to stabilize.

c. Call TSTCHK and run the diagnostic routine if test flag is set. 10 d. Use TLD to look with maximum gain and no windowfor an echo distance between T'(17.78cm) and 1X (33.02cm).

e. If it does not detect an echo within this range, the "Over Ice" indicator on the front panel flashes.

f. If it does detect an echo distance within 7 (1 7.78cm) to 1X (33.02cm), an average of 8 samples is stored in RAM as the Grate distance and the program continues at CU PDET. 15 CUPDET is the Cup Detection routine. This routine collects data using TLD and accepts a cup using the following procedure:

a. The manual fill switch on the front panel is monitored continouslyto assure proper operation. If the manual switch is pressed, the computer begins the Cup Removal routine immediately. The DIP switch is read by calling TSTCHK and if the test flag is set, the CUPDET routine ends and the IN IT routine begins. 20 b. Astable lip distance must be established more than &' (7.62cm) above the GRATE. Astable lip distance is defined as 5 consecutive echo distances from TLD separated by 60 milliseconds that correlate within. 1 (0.25cm). This corresponds to the cup lip being stable for 330 milliseconds. If the stable lip distance istoo close to the crystals (.6" (1.52cm)), the Lip Distance is rejected, the FILL indicator flashes and CU PDET begins again. 25 c. A cup bottom or ice level must be discerned that is more than. 1 " (0. 25cm) above the Grate and more than.Y (1.27cm) below the lip. This is accomplished using T13DW and varying the gain as follows: With minimum gain, obtain an echo distance using TB13W. If the echo distance is not more than. 1 " (0.25cm) closer than the grate, then the gain is increased one step and another sample is taken. if the gain reaches the maximum, the FILL indicatorflashes and the Cup Detection routine begins again. 30 d. The Ice/Bottom height is calculated from the last distance obtained as outlined in (C) above and the GRATE and then stored as the actual ice height. The cup height is calculated from the lip distance and the GRATE. The cup height is divided by 8 and the quotient is multiplied bythe 3 bit binary number input as selected on the ice level programming switches. This allowable ice height is compared to the actual ice height and the Lip Distance. If the actual ice height is greaterthan allowed bythe switch selection, but less 35 thanS' (1.27cm) below the Lip Distance, the cup is rejected and the Cup Removal routine begins. If the actual ice height is withinS' (1.27cm) of the Lip Distance, the cup is not positioned correctly and the FILL indicator flashes before beginning the Cup Detection routine again. If the actual ice height is less than the level selected bythe switch, the FILL routine begins.

The FILL routine controls the complete filling and top off operation. The routine limits the solenoid oper- 40 ation to a maximum of 3 On/Off cycles. After each of the first 2 cycles, the routine waits forthe foam to settle before starting the next cycle. When the cup is full,the Cup Removal routine begins. If the manual switch is pressed at anytime during the FILL routine, the Cup Removal routine begins immediately. The timoutsub routine is called during the time the solenoid valve is turned on by the fill program to monitor the valve on time. If the maximum valve on time is exceeded, the timeout subroutine turns the valve off and does not 45 return on the fill routine. A detailed description of the FILL routine follows:

a. Before the solenoid is actuated, several checks and corrections are made. The gain is initially set at maximum. If the Lip Distance is less than 4", (10.1 6cm), the gain is adjusted with the empirically derived equation:

Gain= Gain - 1/8 W' (10.1 6cm)-Hp distance) If the Lip Distance is less than 4"(10.1 6cm), the Lip Distance is 50 adjusted with the empirically derived equation:

Lip Distance= Lip Distance - 1/8(4"(10.16cm)- Lip Distance) The Time Constant for this particular cup height is calculated with the equation:

Time Constant= cup height/4for SEV and cup height/8 for Fast Flow.

This Time Constant is used in the first of the three cycles to provide an initial fill time proportional to the cup 55 height.

b. The gain must be adjusted such thatthe fluid level is detected and the lip is not during the period when the cup vibrates such as atthe beginning of a FILL. Also if the cup was not positioned perfectly, the Lip Distance maybe slightlyfartherthan originally detected. To adjust the gain, an initial filling period pro- portional to cup height is allowed to minimize cup vibration and adjust gain as necessary. During thistime 60 period the routine uses TB13to check if the echo distance is within.75" (1.91 cm) of the stored Lip Distance. If it is,the gain is reduced one step. If the gain reaches minimum, the Cup Removal routine begins. This time is also used to adjust the Lip Distance as follows: LG RATE is called and if an overflow is detected then the Lip Distance is decremented (an overflow in LGRATE is defined as more than.1 " (0.25cm) less than the stored Lip Distance). If LGRATE detects a missing cup then the Cup Removal routine begins immediately. Atthe end of 65 13 GB 2 190 494 A 13 this period, the solenoid valve stayson.

c. During the next time period the routine uses T13DW to monitorthe liquid level. If the Foamy/Flat switch is set to Foamy, the solenoid turns off when the liquid level is within. 5" (1.27cm) for SEV or.7' (1.78cm) for FFV. If the Foamy/Flat switch is set to Flat, the solenoid is not turned off until the 1 iqu id level reaches.2" (0.51 cm) for SEV and 3' (0.76cm) for FFV, at which time the cup removal routine begins. This condition must 5 be met in two consecutive checks forthe solenoid to turn off. The Grate/Overflow detector subroutine checks to see if the cup has been removed or if T13DW has missed the liquid level rising and an overflow is imminent.

If the cup is missing, the cup removal routine begins. If there is an overflow indicated, the solenoid isturned off.

d. A 4-second pause begins atthis time to allow the foam to settle. The G rate/Overf low subroutine checks 10 continously forthe cup to be removed. If it is, the cup removal routine begins immediately.

e. Afterthe pause, another 4-second time period starts. Using TBD, the foam level is monitored. If the foam drops below.4"(1.02cm) for 10 consecutive checks, this period ends and the firsttop-off period begins.

If the foam does not drop below.411.02cm) within 4 seconds, the first topoff period begins anyway. The Grate/Overf low subroutine continuously cheeks fora missing cup. If a missing cup is detected, the cup 15 removal routine begins.

f. The firsttop-off cycle used TBD to determine if the liquid/foam level is within. 1 " (0.25cm) fora normal 1 1/2 ounces (42.53 grams) per second valve assembly and.05" (0.1 27cm) for thefaster 3 ounces (85.05 grams) per second valve assemblies. If this condition exists, the solenoid is not turned on and this cycle ends.

If not, then the solenoid is turned on until the condition is met. For stability, the solenoid has a minimum on 20 time of.25 seconds.

9. A repeat of "D", "E", and" F" occurs nowto implementthe second top-off cycle with the exception that in "F" the values are.2" (0.51 cm) forthe normal 1 1/2 ounces (42.53 grams) per second valve assembly and.X (0.762cm) forthe faster 3 ounces (85.05 grams) per second valve assembly.

The cup removal routine (CUPREM) turns the fill indicator off, the solenoid off, and the Over-ice indicator 25 on. It uses TLD and waits for an echo distance within.25" (0.64cm) of the Grate. When this condition exists, a new Grate distance is stored, the Over-ice indicator turns off, and the Cup Detection routine begins again.

While the preferred embodiments of this invention have been described above in detail, it is to be under stood thatvariations and modifications can be made therein without departing from the scope of the present invention asset forth in the appended claims. For example, other materials can be used for the crystals and 30 the lenses and other numbers of crystals can be used and other arrangements and locations can be used for the two crystals of the transducer assembly. In addition, a different ultrasonic transmitter and receiver can be used in place of the crystals, if desired, such as various ultrasonic foil devices. While two specific control circuits have been described in detail, other control circuits and other components thereof can be used. While a microcomputer has been described and is preferred, the control circuit can alternatively use a micro- 35 processor connected to a remote RAM and ROM, for example. While the transducer assembly and the control module are shown attached to the dispenser valve assembly, this is not essential; they can be attached to the dispenser and just connected electrical lyto the valve assembly.

This patent application is a divisional patent application of British Patent Application No. 8517430 (pub lished as GB 2161604A). 40

Claims (22)

1. An apparatus for automatically filling a containerwith a beverage comprising:

(a) ultrasonic energytransducer means fortransmitting ultrasonic energy down toward a container sup- 45 porting surface located below a beverage dispensing nozzle and for receiving ultrasonic energy reflected backup from the direction of said surface and for generating corresponding signals; (b) control circuit means for using said generated signals for detecting the presence of a container placed on said surface and below said nozzle; (c) said control circuit means i ncl uding means for controlling the f il ling of a container on said surface with 50 beverage from said nozzle; and (d) said transducer means including at least one crystal having a plastic lens attached to a bottom surface thereof for both coupling the crystal to air and for lensing the crystal.

2. An apparatus as claimed in claim 1 wherein said lens is attached to the respective crystal by adhesive.

3. An apparatus as claimed in claim 2 wherein said crystal is disc-shaped and has a diameter of approx- 55 imately 1/2 inch (1.27 cm) and a thickness of approximately 0.2 inch (0. 51 cm).

4. An apparatus as claimed in claim 3 wherein said lens is shaped to produce or receive afan-shaped beam having along dimension of approximately 21/2 inches and a width of approximately 3/4 inch (1.90cm) at 12 inches (30.48 cm) from said lens.

5. An apparatus as claimed in claim 4wherein said lens is disc-shaped and has a diameter of approx- 60 imately 1/2 inch (1.27 cm) and a thickness of approximately 0.08 inch (0. 20 cm).

6. An apparatus as claimed in any preceding claim wherein said crystal is a ceramic crystal made of PZT-4 or PZT-5a material.

7. An apparatus as claimed in claim 6 including a lens made from a plastic material selected from the class consisting of acrylic, ABS, polystyrene, or polycarbonate. 65 14 GB 2 190 494 A 14

8. An apparatus as claimed in any preceding claim wherein said control circuit means further includes meansfor comparing the actual ice height in said cup with a predetermined allowable ice height for said cup, and then proceeding to fill said cup only if said actual ice height is less than said allowable ice height.

9. An apparatus as claimed in any preceding claim wherein said control circuit means further includes means forfilling said container during an initial filling period fora calculated time period to stabilize said 5 container, priorto completing the filling of said container while monitoring the rising liquid level with ultra sonicenergy.

10. An apparatus as claimed in any preceding claim having a pair of adjacent beverage dispensing valve assemblies and means for operating said adjacent valve assemblies separated in time by synchronizing their operation to different half cycles of an a.c. power supply prevents interference therebetween.

11. An apparatus as claimed in any preceding claim wherein said control circuit means further includes meansfor measuring the filling time and for comparing said measured time to a maximum time period fora container having the height of the container being filled, and forterminating the filling step when the meas ured time exceeds said maximum time.

12. An apparatus as claimed in any preceding claim wherein said control circuit means further includes 15 means for determining if a surface is present above the lip of the container and for terminating filling if such a surface is detected during filling.

13. An apparatus as claimed in any preceding claim wherein said control circuit means further includes means for using full gain while attempting to detect a lip of a container placed on said surface, and forthen reducing the gain while monitoring the rising liquid level during filling. 20

14. A method of automatically filling a container with a beverage, comprising the steps of:

(a) transmitting ultrasonic energy down toward a container support surface located below a beverage dispensing nozzle from an ultrasonic transmitter and receiving ultrasonic energy, with an ultrasonic receiver, reflected backup from the direction of said surface and generating corresponding signals; (b) detecting from said signals the presence of a container placed on said surface and below said nozzle; 25 (c) controlling the filling of said container with beverage from said nozzle; and (d) using a crystal for at least one of said transmitter and receiver and atttaching a plastic lens to a bottom surface of said crystal to both couple the crystal to air and to lens the crystal.

15. A method as claimed in claim 14 further comprising the step of determining the ice height of any ice in a container placed on such surface and comparing the ice heightwith the allowable ice height forthat con- 30 tainer height and proceeding to fill said container only if said determined ice height is less than said allow able said ice height.

16. A method as claimed in claim 14 or 15 wherein said step of controlling the filling of said container further includes the step of initiating the f il ling of said container with a timed f ill cycle to stabilize the con tainer priorto monitoring the rising liquid heightwith ultrasonic energy. 35

17. A method as claimed in claim 14,15 or 16 further comprising operating each of a pair of adjacentvalve assemblies separated in time by synchronizing their operation to different half cycles of an a.c. powersupply, to prevent interference therebetween.

18. A method as claimed in any of claims 14to 17 wherein said step of controlling the filling of the containerfurther includesthe step of calculating a maximum time period forfilling the container, measuring 40 thefilling time, and terminating filling if the filling time exceeds the maximum time.

19. A method as claimed in any of claims 14to 18 wherein said step of controlling the filling of said container further includes the step of attempting to detect a surface above the surface of the container lip and terminating filling if the presence of such a surface is determined to exist.

20. A method as claimed in any of claims 14to 19 wherein said steps of detecting the presence of a 45 container and controlling the f il ling of a container f u rther include the step of using high gain during the step of detecting the presence of a container lip and using low gain during the step of detecting rising liquid level to maskthe container lip.

21. A method as claimed in any of claims 14 to 20 wherein said step of controlling the filling of said container further includes the step of monitoring the rising liquid level with the signals generated from said 50 receiver and including the step of ignoring any echoes received backthat are within approximately 0.25 inches of said container lip.

22. An apparatus as claimed in claim land substantially as hereinbefore described with reference to Figures 1 to 26 or Figures 27to 46 of the accompanying drawings.

55 Printed for Her Majesty's Stationery Office by Croydon Printing Company (11 K) Ltd,9187, D8991685. Published by The Patent Office, 25 Southampton Buildings, London WC2A lAY, from which copies maybe obtained.