FLOW DETECTION CIRCUIT

Abstract

CIRCUIT FOR DETECTING A FLOW, ENCLOSURE AND DISPENSING DEVICE FOR DISPENSING A BEVERAGE. A dispensing system for a beverage comprises a hole in a tap system to house a duct. Along the hole, near or in the duct, at least two electrodes are provided so that at least in some locations along the duct, the two electrodes are provided opposite each other with the duct in between, thus constituting a capacitor. An oscillating signal is supplied to one electrode and a signal is read from the other electrode. As a beverage is drawn through the duct into a container, the capacitance of the capacitor changes. The flowing beverage may have different characteristics, but the capacitance may also change as the beverage in the duct is in conductive contact with a container that may be in contact with a ground contact. The change in capacitance results in a change in the amplitude of a detection circuit connected to the second electrode.

Description

1 / 22 FLOW DETECTION CIRCUIT TECHNICAL FIELD

[001] The various aspects and modalities of the same relate to a circuit and device for detecting a flow through a duct as part of a system for dispensing beverages, using a capacitive sensor. BACKGROUND

[002] US6545488B2 discloses a system for measuring capacitive flow through a duct in a large transportation system. Two electrodes are helically wound around the duct and a signal is applied to the electrodes. Following a change in flow through the duct, a frequency of a signal in a sensing circuit varies. The sensing is transformed into a voltage signal, which is used for further processing. SUMMARY

[003] When using capacitance variation to change an oscillating frequency, the use of an inductor is highly preferable. Inductors are bulky and relatively expensive circuit components. Furthermore, for further conversion of frequency changes to a voltage signal, a significant amount of circuitry is required. It is preferable to provide a more efficient arrangement for detecting flow through the duct of a beverage dispensing system.

[004] A first aspect provides a circuit for detecting a flow through a duct of a tap for dispensing beverages. The circuit comprises an alternating signal source having a signal terminal arranged to provide an alternating signal to a capacitive element comprising two electrodes provided on opposite sides of the duct along at least part of the length of the duct and a detection circuit. The detection circuit is arranged to be connected to the capacitive element and arranged to detect a Petition 870220044843, dated 05 / 24 / 2022, p. 94 / 156 2 / 22 signal amplitude value, the detection circuit being arranged to provide a detection signal based on the signal amplitude value at a detection terminal comprised by the detection circuit. The flow detection circuit also comprises a processing circuit arranged to receive the detection signal, determine whether the detection signal satisfies a predetermined criterion; and provide a flow signal if the predetermined criterion is met.

[005] This system operates with a frequency throughout the circuit, thus reducing complexity. Furthermore, it can be implemented in the analog domain, in the digital domain, or partially in the analog domain and partially in the digital domain without departing from this aspect.

[006] In one implementation, the alternating signal source has a signal terminal arranged to be connected to a first capacitor electrode provided along at least part of a length of the duct and the detection circuit is arranged to be connected to a second capacitor electrode provided along at least part of a length of the duct to receive an electrode signal.

[007] An additional implementation further comprises an addition circuit to sum the detection signal and a reference control signal to provide a controlled detection signal, wherein the processing circuit is further arranged to provide a reference control signal based on the controlled detection signal.

[008] The person skilled in the art will understand that a subtractor also encompasses the definition of an adder. With this implementation, large variation in the signal amplitude at the second electrode can be controlled by spanning the limits, so that flow detection and flow characteristics can be more convenient. Petition 870220044843, dated 05 / 24 / 2022, page 95 / 156 3 / 22

[009] In another implementation, the detection circuit comprises a peak detection circuit and the detection signal is based on the output of the peak detection signal. Whereas other types of circuits can be used to determine an amplitude value, such as multipliers, a peak detector is preferred for determining the amplitude.

[010] In yet another embodiment, the detection circuit is arranged to detect load fluctuations at the second electrode and to provide a voltage signal based on the detected fluctuations. Considering that the circuit can be implemented as current-based, a set of voltage-based circuits is preferred.

[011] A second aspect provides an enclosure for housing a duct for a beverage dispensing tap. The enclosure comprises an elongated bore having a proximal opening and a distal opening for housing and guiding the duct, a first electrode provided over at least part of the length of the bore and a second electrode provided along at least part of the length of the bore. In this enclosure, the first electrode is arranged to be connected to the signal terminal of a circuit according to any of the preceding claims; and the second electrode is arranged to be connected to the sensing terminal of a circuit according to the first aspect. Such an enclosure comprises the preferred electrodes for operating the circuit according to the first aspect, providing an advantageous arrangement for housing a duct for dispensing beer – or other beverage – and sensing the flow of beer.

[012] In one embodiment, the casing comprises a first carcass and a second carcass, the first carcass comprising a first elongated recess and the second carcass comprising a second elongated recess such that when the first carcass and the second carcass are joined together to Petition 870220044843, dated 05 / 24 / 2022, page 96 / 156 4 / 22 forming the involute, the first recess and the second recess provide at least part of the duct. This enclosure is advantageous for the use of a disposable duct, which can be conveniently inserted and removed from the hole. Furthermore, if the enclosure is provided in two halves, electrodes and circuit assembly can all be provided in one and the same part of the housing.

[013] A third aspect provides a dispensing device for dispensing a beverage. The device comprises the enclosure according to the second aspect, the circuit according to the first aspect. In this device, the first electrode is connected to the signal terminal; and the second electrode is connected to the detection terminal. BRIEF DESCRIPTION OF THE FIGURES

[014] The various aspects and implementations thereof will now be elucidated together with the figures. In the figures: Figure 1: shows a beverage dispensing system; and Figure 2 A: shows a first flow detection circuit; Figure 2B: shows a second flow detection circuit; Figure 3 shows another flow detection circuit; and Figure 4 shows an electrical circuit equivalent to the other flow detection circuit. DETAILED DESCRIPTION

[015] Figure 1 shows a beer dispensing system 100 as an implementation of a dispensing device for dispensing beverages. The beer dispensing system 100 comprises a duct 120 to provide or form a channel for beer to flow from a reservoir such as a keg or a large tank (not shown) to a dispensing valve 122. The valve 122 may be an integral part of the duct or the duct 120 may be coupled to the valve 122. The duct 120 is, or at least comprises, a tube. Petition 870220044843, dated 05 / 24 / 2022, page 97 / 156 5 / 22 preferably flexible and more preferably resilient comprising an organic polymer, such as PVC, silicon, polyethylene, or other or a combination thereof.

[016] The duct 120 is provided and extends through a hole 114 in a housing 112 which forms a support for a dispensing tap 116. The dispensing tap 116 comprises a tap handle 118 for operating the dispensing valve 122. Encompassing the housing 112, a first electrode 132 and a second electrode 134 are provided. The first electrode 132 and the second electrode 134 are provided so that they are located on opposite sides of the duct 120 for at least part of the length of the duct 120.

[017] Such a constellation can be achieved by providing the first electrode 132 and the second electrode 134 in the casing, on opposite sides on the inner wall of the bore 114 and substantially parallel to the length of the bore 114 and the duct 112. In this constellation, the electrodes are provided opposite each other along their entire length. Alternatively, the electrodes are provided in any other way so that they are provided on opposite sides for at least one or more parts of the length of the bore 114.

[018] The beer dispensing system further comprises a flow detection circuit 200 to detect whether beer is being extracted from the reservoir using the beer dispensing system 100. The flow detection circuit 200 is connected to the first electrode 132 and the second electrode 134.

[019] The housing can be provided by means of two housings to facilitate the removal and insertion of the duct 120. This is particularly advantageous if the duct 120 is a disposable duct. In such an embodiment, the first electrode 132 and the second electrode 134 are preferably provided in the same part of the Petition 870220044843, dated 05 / 24 / 2022, page 98 / 156 6 / 22 housing, along with a flow detection circuit 200. The duct 120 can be embedded in a first housing having a recess as part of the hole 114.

[020] Subsequently, a second casing is joined to the first casing to form the enclosure 112. Alternatively, the duct 120 is routed through the bore 114 with a closed bore, i.e., with the two halves joined, or, if the enclosure 112 mainly comprises a single unit through which the bore is provided. The duct 120 may be inserted into the bore 114 from above or below, in the constellation shown in Figure 1. The bore 114 may be provided within a solid enclosure 112 or as a rigid or flexible tube or pipe in a hollow enclosure 112. The shape and cross-sectional dimensions of the bore 114 may vary or be substantially the same along the length of the bore 114.

[021] The duct 120 is preferably provided within the hole 114 so that it does not come into contact with the first electrode 132 and the second electrode 134. Whereas the duct 120 is preferably provided as a flexible dispensing line comprising predominantly an organic polymer which is electrically insulating, the condensation of liquid, and water in particular, can provide a conductive path. Therefore, the duct 120 is provided at a distance from the first electrode 132 and the second electrode 134. Alternatively or additively, the first electrode 132 and the second electrode 134 are provided with an insulating film, at least on one side facing the inner space of the hole 114.

[022] Hole 114 can be supplied as a rigid guide for duct 120 or as a flexible guide. In the latter case, hole 114 can be supplied comprising a flexible tubing within which the duct 120 tubing can be supplied.

[023] Figure 2 A shows the flow detection circuit 200 in detail. Petition 870220044843, dated 05 / 24 / 2022, page 99 / 156 7 / 22 additional. Figure 2 A shows the preferred functional components for implementing the flow detection circuit 200. The flow detection circuit 200 comprises a signal generator 202 to provide an alternating signal, as a voltage source or current source. Preferably, the signal generator 202 generates a sinusoidal wave, preferably at a frequency between 1.5 kHz and 3 kHz, more preferably between 2 kHz and 2.5 kHz, and most preferably at 2.3 kHz. Note that depending on the values ​​of the various components, other frequency values ​​can be selected, between 1 kHz and 4 kHz, between 5 kHz and 101 kHz, between 101 kHz and 5^101 kHz or above, up to 102 kHz and upwards.

[024] In another implementation, the signal generator generates another waveform, including at least one triangular signal, a block wave, a sawtooth signal, another, or a combination thereof. The signal frequency is preferably defined, although it may be variable.

[025] The generated signal is applied to the first electrode 132. The signal may optionally be supplied via an intermediate stock, decoupling capacitor, a resistor, another type of impedance, or a combination thereof. Together with the second electrode 134, the first electrode 132 constitutes a capacitor 204. Charge variations on the first electrode 132 due to the applied alternating signal will result in charge variations on the second electrode 134, as is the basic principle of a capacitance such as capacitor 204.

[026] Fluctuations in charge at the second electrode 134 result in an alternating current at the second electrode 134. The amount of fluctuation depends on the characteristics of the medium between the first electrode 132 and the second electrode 134. Such characteristics include, but are not limited to, the distance between the electrodes, the permittivity of the medium or medium between the electrodes, and other characteristics of the medium or medium. Petition 870220044843, dated 05 / 24 / 2022, pp. 100 / 156 8 / 22

[027] Alternating current is supplied to an amplifier, preferably a transimpedance amplifier 206, to convert the alternating current into an alternating voltage. The alternating voltage has the same frequency as the signal supplied by the signal generator 202. The amplified voltage signal is supplied to a bandstop filter or notch filter 208 which has a center frequency substantially equal to a supply frequency of the mains voltage. For most of the world this is 50 Hz, for some regions, including the Americas, it is 60 Hz. In some locations, other frequencies may be applied. Alternatively or additionally, to reduce the influence of the mains current, the enclosure 112 may be provided with shielding to reduce electromagnetic interference in the flux detection circuitry.

[028] The alternating signal is subsequently provided to a bandpass filter 210. The bandpass filter 210 has a center frequency substantially equal to the frequency of the signal provided by the signal generator 202. The bandpass filter 210 can be provided comprising capacitances and inductances to define slopes and center frequency independently. However, as inductances can be bulky and relatively expensive, the use of a multi-feedback bandpass filter (MFB filter) is preferred.

[029] The filtered signal is thus fed to a 212 rectifier. The 212 rectifier in this implementation is a half-bridge rectifier. Alternatively, the 212 rectifier can be implemented as a full-bridge rectifier. However, the input signal is a data signal of which only the top output level of the rectified signal is relevant, which is why it is not necessary to rectify the entire signal - as opposed to a power signal.

[030] The rectified signal is provided to a level detection circuit 214 Petition 870220044843, dated 05 / 24 / 2022, pp. 101 / 156 9 / 22 to detect a peak level of the rectified signal. From the filtered and rectified signal, the peak level is determined and the level detection circuit and the output of the peak detector 214 is provided to an amplifier 216.

[031] The amplified signal at the amplifier output is fed to a closed feedback control loop. The closed feedback control loop comprises an adder 218 – which can, with minor design modifications, also be implemented as a subtractor – and a control circuit 220. The control circuit 220 is preferably implemented as a PID control circuit 220 – a proportional-integral-derivative controller.

[032] The 220 PID control circuit is preferably provided as part of a 240 microcontroller as a processing module. The processing module may also be incorporated as a microprocessor or central processing unit or any other electronic computing circuit arranged to execute computer-readable instructions and suitable for manufacturing any device according to the various aspects and modalities thereof. Therefore, the output of the adder 218 is sampled and digitized prior to being provided to the 220 PID control circuit. The output of the 220 PID control circuit is initially digital and converted to the analog domain prior to being provided to the adder 218.

[033] One reason for providing the closed-loop feedback control is that, depending on the container in which the beer is dispensed, such as a glass or a pitcher, the variations in the signals can vary significantly in magnitude. The closed-loop power control ensures that the analog output of the circuit as supplied to the microcontroller is provided in the appropriate range, for example, between 0 and 5 Volt, between 0 and 3.3 Volt, between 0 and 2.5 Volt or another range. Petition 870220044843, dated 05 / 24 / 2022, pp. 102 / 156 10 / 22

[034] The digitized signal provided to the PID control circuit 220 is also provided to a central control circuit 242. The central control circuit 242 is part of the microcontroller 240, whose functionality may be programmed or already available from the factory. The central control circuit evaluates the digitized output signal of the adder 218 – the controlled signal – to one or more predetermined values. These values ​​may be stored in a storage module 244, supplied separately or as part of the microcontroller 240.

[035] The values ​​can also be adjusted based on ambient temperature. For this purpose, the microcontroller 240 is connected to a temperature sensor 250. The temperature sensor 250 can be supplied close to the duct 120, for example, near or between the first electrode 132 and the second electrode 134. In this configuration or an equivalent configuration, the temperature sensor 250 can be used to measure the temperature of the beverage being dispensed. This allows control over the quality of the dispensed beverage – with beer, the serving temperature is very important for the overall experience of drinking a premium lager – and allows monitoring of a refrigeration system to cool the beverage.

[036] If the controlled signal is above or below a certain predetermined value, it can be determined that beer is being dispensed from the beer dispensing system 100. It has been determined that as beer is being dispensed from the beer dispensing system 100, the level of alternating current at one terminal of the second electrode varies. This variation in the amplitude of the current received from the capacitor depends on the type of container used – glass, jug, pitcher or bucket – and how the container is being held – by the whole hand or only by the tips of some fingers.

[037] Therefore, since the controlled signal is at a certain value, it can Petition 870220044843, dated 05 / 24 / 2022, pp. 103 / 156 11 / 22 if first it detects that the beer is being extracted and into a particular container, such as a jug, a pitcher, or a glass. Second, it can be established what type of container – jug, glass, pitcher – the beer is being extracted from. Third, it can be established how the container is being held. Fourth, as the detection is based on the presence of duct 120 in hole 114, between the first electrode 132 and the second electrode 134, it can be detected if duct 120 is present in any way.

[038] Based on the determinations, further data processing can be performed. A suitable beer is being extracted by fully opening valve 122 of tap 116, commonly performed by turning the handle of tap 118, for example, to about ninety degrees. This means that the dispensing valve is open or closed; the flow is maximum or zero. If the extraction time period can be determined based on the processing of the controlled signal (or other signal in the chain) and multiplied by the maximum flow, the amount of beer extracted can be calculated. In this way, a pre-warning can be issued if a keg or other reservoir is nearly empty.

[039] The microcontroller 240 also comprises an actuator circuit 246 which may be programmed or already available from the manufacturer. The actuator circuit is arranged to control an actuator outside the microcontroller 240, such as the light-emitting diode 260. The light-emitting diode 260 may provide a lighting function to illuminate the enclosure 112 or part thereof. Alternatively or additively, other light sources, a display screen to show text, video or still images, an audio source or other peripheral devices may be controlled.

[040] With the container type determined, the container type can be shown on a screen near the dispensing system 100. And if it is determined how the container is being held, feedback can be Petition 870220044843, dated 05 / 24 / 2022, pp. 104 / 156 12 / 22 provided to a person using dispensing system 100. For example, if it is preferred that a cup be held with the fingertips rather than the whole hand, the user can be instructed to take corrective action if it is determined that the cup is being held with the whole hand.

[041] Another action can be taken by a remotely located actuator. For this purpose, the flow detection circuit comprises a communication module 248 connected to the central control circuit 242 or another part of the microcontroller 240. Instructions for remotely located actuators can be provided to the communication module 248, which transfers the instructions using a protocol such as IEEE 802.11, popularly known as WiFi, Zigbee, Bluetooth, LoRa, an LTE protocol, or another protocol or a combination thereof. Alternatively or additively, data can be received via the communication module 248, for example, to program the microcontroller 240.

[042] The dispensing system 100 thus provided is preferably used for dispensing beer, but can also be used for dispensing other beverages such as cider, alcopops or soft drinks.

[043] The filters used in the flow detection circuit 200 are preferably active filters, which can be implemented using commercially available operational amplifiers.

[044] In the embodiments discussed above, the first electrode 132 and the second electrode 134 are provided on either side of the hole 114 - or the duct 112, and the first electrode 132 is connected to the signal generator 202 and the second electrode 134 is connected to the signal detection circuit to the right of the capacitive element that the capacitor 204 incorporates. In another embodiment, the capacitor 204 is provided in a capacitive divider, in series or parallel to an additional capacitive element having a substantially fixed capacitance value. Petition 870220044843, dated 05 / 24 / 2022, pp. 105 / 156 13 / 22

[045] As the capacitance value of capacitor 204 changes after the beer is extracted through duct 112 and the amplitude of a signal supplied by the signal generator changes, depending on the configuration, a change in current through or voltage across capacitor 204 and / or across / on the additional capacitor may occur. This change can be detected and used to determine if a liquid flowing through the duct is dispensed into a container. If the capacitors are connected in parallel, a change in current should be detected, and if the capacitors are connected in series, a change in voltage should be detected. Note that this is related to the signal amplitude, not the actual value.

[046] Figure 2 B shows an alternative embodiment of the flow detection circuit 200. Part also present in the embodiment shown in Figure 2 A and variations thereof discussed above with the same reference signal as Figure 2 A has equivalent functionality and will not be discussed in further detail unless necessary for better intelligibility.

[047] The flow detection circuit represented by Figure 2 B comprises an analog-to-digital converter 272 and a digital-to-analog converter, connected to a microcontroller 280 (equivalent to the microcontroller 240 of Figure 2 A) - which can also be implemented using a microprocessor or an equivalent electronic computing device.

[048] The 280 microcontroller comprises, either programmably or wired, a Fast Fourier Transform (FFT) module 284 for applying a discrete transformation of a signal to a frequency domain, a signal generator 282, a convolution module 286, and a step function generator 288. Alternatively, one or more of these parts may be implemented in a separate circuit. The other parts of the microcontroller Petition 870220044843, dated 05 / 24 / 2022, pp. 106 / 156 14 / 22 280 are the same or similar or equivalent to the microcontroller parts 240 represented and discussed together with Figure 2 A.

[049] In this embodiment, the 282 digital signal generator is a digital signal generator and implemented in the 280 microcontroller. The signal, as shown in Figure 2 A, is preferably supplied at 7.5 kHz, but can vary between 5 kHz and 101 kHz, between 101 kHz and 5^101 kHz or above, up to 102 kHz and upwards. Alternatively, the frequency can vary between 1.5 kHz and 3 kHz, more preferably between 2 kHz and 2.5 kHz and most preferably at 2.3 kHz.

[050] The signal generated preferably has a sinusoidal waveform, but it can also have a square, triangle, sawtooth or other waveform, or any combination thereof. The signal generated by the digital signal generator is transformed into the analog domain by means of the digital-to-analog converter 274 and supplied to the first electrode 132.

[051] The signal received from the second electrode 134 and provided by the bandstop filter 208 is converted to the digital domain by means of the analog-to-digital converter 272 and provided to the microprocessor 280. In the microprocessor 280, the digitized signal is converted to the frequency domain by means of the FFT module 284, using the signal generated by the digital signal generator 282. This means that the FFT module 284 and capacitor 204 are supplied with one and the same signal, at the same frequency. This allows for improved detection of the signal supplied to the first electrode 132 and received by the second electrode 134 – and changes in that signal due to liquid flowing through the duct 120 or not. And this allows the signal transferred from the digital signal generator 282, via capacitor 204, to be filtered from the data received from the analog-to-digital converter 272, as both signals have the same frequencies.

[052] The signal provided by the FFT 284 module is provided to the module of Petition 870220044843, dated 05 / 24 / 2022, pp. 107 / 156 15 / 22 convolution 286 and convolved with a step function provided by the 288 step function generator. The 288 step function generator does not necessarily have to be a real signal generator, but can also be implemented as values ​​stored in memory and, as such, provided to the 286 convolution module.

[053] The convoluted signal, as well as the direct output of the FFT module 284, are provided to the central control circuit 242. The convoluted signal is used to detect whether the liquid in the duct 120 is flowing or not. The direct output of the FFT module 284 is used to detect a level of the signal received from the second electrode 134, as received from the analog-to-digital converter 272.

[054] Figure 3 shows a detection arrangement 300 as another implementation of a detection configuration according to the aspects discussed above for use, for example, in the beer dispensing system 100. Figure 3 shows the detection arrangement 300 comprising the beer conduit module 302 and a detection module 304. The beer conduit module 302 comprises a beer conduit 312 connected at a distal end to a beer keg 306 arranged to contain beer – or other dispenseable liquid – and connected at a proximal end to a tap such as the dispensing tap 116, as shown in Figure 1.

[055] Around the beer conduit 312, a transmitting electrode 314, a first receiving electrode 316 and an optional second receiving electrode 318 are provided. Between the transmitting electrode 314 and the first receiving electrode 316, an optional first shielding electrode 320 is provided and between the first receiving electrode 316 and the second receiving electrode 318, an optional second shielding electrode 322 is provided. The electrodes are preferably not provided in direct contact with the beer conduit, but this may be the case in another implementation. Petition 870220044843, dated 05 / 24 / 2022, pp. 108 / 156 16 / 22

[056] The electrodes preferably completely enclose the beer conduit 312. In an implementation wherein the casing 112 (Figure 1) is provided having two or more casing parts, the electrodes may be constituted as comprising several electrode parts, wherein each part is composed of a casing part of the casing 112. With the casing 112 assembled, the electrode parts of each electrode are in conductive contact with each other – but not with parts of other electrodes. In another implementation, not all casing parts comprise parts of each electrode, in which case each electrode may not completely enclose the beer conduit 312.

[057] Preferably, the shielding electrodes, if present, are measured along the length of the beer conduit 312 preferably shorter than the transmitting electrode 312, the first receiving electrode 316 and the second receiving electrode 318. The shielding electrodes are connected to the ground level or to the zero reference of the signal source V1.

[058] The detection module 304 comprises a signal source V1, a first reference capacitor C1 and a second reference capacitor C2. The signal source V1 is substantially the same, similar or at least equivalent to the signal generator 202 in Figure 1, unless otherwise indicated.

[059] The signal source V1 is connected to ground or a zero reference at one terminal and to the transmitting electrode 314 at the second terminal and the first terminal of the second reference capacitor C2 at the first terminal. A reference voltage terminal is provided between the second terminal of the second reference capacitor C2 and the first terminal of the first reference capacitor C1. The second terminal of the first reference capacitor C1 is connected to ground or to the Petition 870220044843, dated 05 / 24 / 2022, pp. 109 / 156 17 / 22 zero reference terminal of signal source V1.

[060] The sensing module 304 comprises a first signal comparator 342 and a second signal comparator 344. The signal comparators are arranged to compare analog input signals and to provide an output signal in response to the comparison operation. The signal comparators can be implemented using analog operational amplifier circuits. Alternatively or additively, signal comparison can be performed in a digital domain. For this purpose, the signal comparators can comprise analog-to-digital converters. The first signal comparator 342 and a second signal comparator 344 can be implemented equivalently to the flow sensing circuit 200 as represented and discussed in conjunction with Figure 2A and Figure 2B.In this implementation, the transmitting electrode 314 and the first receiving electrode 316 form a first capacitor equivalent to capacitor 204 as shown in Figure 2A and Figure 2B; the transmitting electrode 314 and the second receiving electrode 318 form a second capacitor also equivalent to capacitor 204 as shown in Figure 2A and Figure 2B.

[061] Comparison by signal comparators can occur instantaneously, in a continuous time domain. Alternatively or additively, comparison can occur in an amplitude domain, comparing amplitudes of the reference voltage and a voltage as detected by means of the first receiving electrode 316 and the second receiving electrode 318. Such comparison in the amplitude domain can occur continuously or at regular intervals, for example, every fifth, tenth or twentieth of a second up to every one or two seconds.

[062] A first signal comparator 342 is connected to the first receiving electrode 316 and to the reference voltage terminal. A second Petition 870220044843, dated 05 / 24 / 2022, pp. 110 / 156 The 18 / 22 signal comparator 344 is connected to the second receiving electrode 318 and to the reference voltage terminal. In this configuration, the first signal comparator 342 compares voltages at the first signal electrode 316 with the reference voltage, and the second signal comparator 344 compares the voltage at the second signal electrode 318 with the reference voltage.

[063] Comparators provide an output signal based on the difference between the input voltages. Additional signal processing, prior to comparison, after comparison, or both, may occur, in a manner as discussed in conjunction with Figure 2 A, Figure 2 B, or a combination thereof.

[064] Figure 3 shows a parasitic capacitance C6 from beer conduit 302 to ground to model a connection between beer conduit 302 and ground via a person drawing a beer. Additionally, a keg parasitic capacitance C7 is drawn to model a capacitance from beer conduit 302 to ground via beer keg 306 and beer conduit 302.

[065] Figure 4 shows a circuit diagram 400 equivalent to the configuration represented by Figure 3. Figure 4 shows the first reference capacitor C1 and the second reference capacitor C2. Figure 4 also shows a first receiving terminal Rx1 providing an input to the first comparator 342 and a second receiving terminal Rx2 providing an input to the second comparator 344. The transmitting electrode 314 is modeled as a transmitting capacitance C3, the first receiving electrode 316 is modeled as a first receiving capacitance C4, and the second receiving electrode 318 is modeled as a second receiving capacitance C5.

[066] Beer conduit 312 is modeled as a chain of Petition 870220044843, dated 05 / 24 / 2022, pp. 111 / 156 19 / 22 resistances; a first conduit resistance R1 between the transmitting electrode 314 and the first receiving electrode 316 and a second conduit resistance R2 between the first receiving electrode 316 and the second receiving electrode. The proximal end of the beer conduit 312 to the dispensing tap 116 is modeled as a third conduit resistance R3 and the dispensing tap 116 itself is modeled as a tap resistance R5. The distal end of the beer conduit 312 between the transmitting electrode 314 and the keg 306 is modeled as a fourth conduit resistance R4 and the resistance across the keg-to-keg parasitic capacitance C7 is modeled as a keg resistance R6.

[067] During a dispensing operation of the beer dispensing system 100, while dispensing beer, at least one of the modeled conduit resistors and the transmitting electrode 314 and the receiving electrodes change. As a result, the voltages at the first receiving terminal Rx1 and the second receiving terminal Rx2 change. With the values ​​of the first reference capacitance C1 and the second reference capacitance C2 being substantially constant, the reference voltage is substantially constant.

[068] The variation of at least in the value of capacitances and / or resistances on one side of the bridge and no substantial change on the other side of the capacitive bridge circuit allows the first comparator 342 and the second comparator 344 to determine the change in the value of at least one of the modeled conduit resistances and the transmitting electrode 314 and the receiving electrodes when determining differences between the reference voltage and the voltages at the first receiving terminal Rx1 and the second receiving terminal Rx2.

[069] Note that the second detection electrode 318 and the second comparator 344 are optional, however, preferred to increase accuracy. Petition 870220044843, dated 05 / 24 / 2022, pp. 112 / 156 20 / 22 to determine a flow through beer conduit 312 and, optionally, the amount of the flow.

[070] In the description above for Figure 3 and Figure 4, it is noted that certain elements can be connected to a zero reference or to a ground terminal. A ground terminal is defined as a terminal having a fixed voltage level – usually zero – relative to ground. A zero reference level is a voltage level of a terminal of a voltage source or other particular terminal in a circuit. In the implementations discussed above, this terminal is the lower terminal of the voltage source V1, as represented by Figure 3. The zero reference is not always the same as the voltage level of the ground terminal (the ground level), as the zero reference can oscillate relative to the ground level. The zero reference is only equal to the ground level if the zero reference terminal is connected to ground – such as the ground conductor of a wall socket or similar or equivalent.

[071] Referring to Figure 3, the shielding electrodes are connected at the same level as the zero reference of V1, as is the terminal of the first reference capacitance C1 opposite the reference terminal. These nodes can be connected to ground, but this does not have to be the case. The parasitic keg capacitance C7 is at the terminal opposite the distal end of the beer conduit 312 to ground. The latter is the case as the beer keg 306 is commonly placed in a beer cellar and / or refrigerator, distant from the beer dispensing system 100, which does not provide a viable option for connecting the zero reference to the environment of the beer keg 306.

[072] In another implementation, the signal provided at the first receiving electrode 316 and the second receiving electrode 318 is not compared to a voltage of the capacitive divider consisting of C1 and C2, but fed into the circuit. Petition 870220044843, dated 05 / 24 / 2022, pp. 113 / 156 21 / 22 represented by Figure 2 A, with the signal at the receiving electrodes being supplied to the transimpedance amplifier 206. Alternatively, an equivalent circuit may be provided, with or without the appropriate filters, in analog or digital form. In such embodiment, the first reference capacitance C1 and the second reference capacitance C2 may be omitted. Additively or alternatively, the first comparator 342 and the second comparator 344 may be omitted.

[073] Similarly, the electrodes represented by Figure 1 can also be part of a capacitive bridge circuit, as represented by Figure 3 and Figure 4.

[074] In summary, the aspects relate to a beverage dispensing system comprising a hole in a tap system to house a duct. Along the hole, near or in the duct, at least two electrodes are provided so that at least in some locations along the duct, the two electrodes are provided opposite each other with the duct in between, thus constituting a capacitor. An oscillating signal, preferably having a sinusoidal waveform, is provided to one electrode and a signal is read from another electrode. As a beverage is drawn through the duct into a container, the capacitance of the capacitor changes. The flowing beverage may have different characteristics, but the capacitance may also change as the beverage in the duct is in conductive contact with a container which may be in contact with a ground contact. The change in capacitance results in a change in the amplitude of a sensing circuit connected to the second electrode.

[075] In the description above, it will be understood that when an element, such as a layer, region, or substrate, is referred to as being in or on another element, the element is directly within another element or elements. Petition 870220044843, dated 05 / 24 / 2022, pp. 114 / 156 Intermediate values ​​(22 / 22) may also be present. It should also be understood that the values ​​given in the description above are examples and that other values ​​may be possible and / or sought.

[076] Furthermore, the invention can also be implemented with fewer components than those provided in the embodiments described in the present invention, wherein one component performs multiple functions. Similarly, the invention can be implemented using more elements than those represented in the Figures, wherein the functions performed by one component in the provided embodiment are distributed among several components.

[077] It should be noted that the figures are merely schematic representations of embodiments of the invention which are given as non-limiting examples. For the sake of clarity and conciseness of description, the features are described in the present invention as part of the same embodiments or of separate embodiments; however, it shall be understood that the scope of the invention may include embodiments having combinations of all or some of the features described. The word comprising does not exclude the presence of other features or steps beyond those listed in a claim. Furthermore, the words 'a' and 'an' should not be interpreted as limited to 'only one', but are used to mean 'at least one' and do not exclude a plurality.

[078] A person skilled in the art will readily appreciate that various parameters and values ​​thereof disclosed in the description may be modified and that various disclosed and / or claimed embodiments may be combined without departing from the scope of the invention.

[079] It is stipulated that reference signs in claims do not limit the scope of the claims, but are merely inserted to increase the readability of the claims. Petition 870220044843, dated 05 / 24 / 2022, pp. 115 / 156

Claims

1 / 5 CLAIMS 1. Circuit (200, 304) for detecting a flow through a duct (120, 312) of a tap (110) for dispensing beverages, the circuit (200, 304) comprising: an alternating signal source (202, V1) having a signal terminal arranged to provide an alternating signal to a first electrode of a capacitive element (132, C4, C5) comprising two electrodes (132, 134, 314, 316, 318) provided adjacent to the duct along at least part of the length of the duct and the signal source further comprising a zero terminal; a detection circuit (240, 344, 342) arranged to be connected to the capacitive element to receive an input signal from a second electrode of the capacitive element and arranged to detect a signal amplitude value, the detection circuit (240, 344, 342) being arranged to provide a detection signal based on the signal amplitude value at a detection terminal comprised by the detection circuit (240, 344, 342);an electronic digital processing circuit (240, 242) arranged to: - receive the detection signal; - determine whether the detection signal satisfies a predetermined criterion; and - provide a stream signal if the predetermined criterion is met; characterized in that - the detection circuit (240, 344, 342) comprises a signal transformation circuit (284) to transform the signal received from the second electrode from the time domain to the frequency domain; and - the detection signal is based on the transformed signal.

2. Circuit (200, 304), according to claim 1, characterized in that: Petition 870260035882, dated 04 / 16 / 2026, page 14 / 18 2 / 5 the alternating signal source has a signal terminal arranged to be connected to a first capacitor electrode provided along at least part of a length of the duct; and the detection circuit (240, 344, 342) is arranged to be connected to a second capacitor electrode provided along at least part of a length of the duct to receive an electrode signal.

3. Circuit (200, 304), according to claim 1 or 2, characterized in that the alternating signal source is arranged to provide the alternating signal to the signal transformation circuit (284).

4. Circuit (200, 304), according to claim 3, characterized in that the alternating signal source provides a digital source signal and the circuit (200, 304) comprises a digital-to-analog transformer to convert the digital source signal into an analog source signal to provide the analog source signal to the first electrode.

5. Circuit (200, 304), according to any one of claims 1 to 4, characterized in that: - the detection circuit (240, 344, 342) additionally comprises a convolution module for convoluting the frequency domain transformed signal with an auxiliary signal; and - the detection signal is based on the output of the convolution module.

6. Circuit (200, 304), according to claim 5, characterized in that the auxiliary signal is a step function.

7. Circuit (200, 304), according to any one of claims 1 to 6, characterized in that it further comprises an actuator connected to the processing circuit (240, 242), wherein the processing circuit (240, 242) is arranged to actuate the actuator based on the flow signal. Petition 870260035882, dated 16 / 04 / 2026, page 15 / 18 3 / 5 8. Enclosure for housing at least part of a duct for a beverage dispensing tap, the enclosure characterized in that it comprises: - an elongated hole having a proximal opening and a distal opening for housing and guiding the duct; - a first signal electrode provided over at least part of the length of the hole; - a second signal electrode provided over at least part of the length of the hole; the circuit (200, 304) defined in any one of claims 1 to 7; wherein the first signal electrode and the second signal electrode form a capacitive element connected to the alternating signal source and to the detection circuit (240, 344, 342) of the circuit (200, 304).

9. Enclosure according to claim 8, characterized in that: - the first signal electrode is arranged to be connected to the signal terminal of a circuit (200, 304) defined in any one of claims 2 to 7; and - the second signal electrode is arranged to be connected to the detection terminal of a circuit (200, 304) defined in any one of claims 2 to 7.

10. Enclosure, according to claim 8 or 9, characterized in that: - the first signal electrode at least partially surrounds the bore; - the second signal electrode at least partially surrounds the bore; and - the first signal electrode and the second signal electrode are spaced along the length of the bore. Petition 870260035882, dated 04 / 16 / 2026, page 16 / 18 4 / 5 11. Enclosure, according to claim 8 or 9, characterized in that the first electrode and the second electrode are provided substantially parallel to the hole, preferably opposite each other relative to the length of the cavity.

12. Enclosure, according to any one of claims 9 to 11, characterized in that it further comprises a tap arranged to control a flow of beverage through the duct.

13. Dispensing device for dispensing a beverage, the device characterized in that it comprises: - the enclosure defined in any one of claims 8 to 12; - the circuit (200, 304) defined in any one of claims 1 to 7; wherein the first signal electrode and the second signal electrode form a capacitive element coupled to the alternating signal source and to the detection circuit (240, 344, 342) of the circuit (200, 304).

14. Dispensing device according to claim 13, characterized in that: - the circuit (200, 304) is a circuit (200, 304) defined in any of claims 2 to 7; - the first signal electrode is coupled to the signal terminal; and - the second signal electrode is coupled to the detection terminal.

15. Dispensing device, according to claim 12 or 14, characterized in that the processing circuit (240, 242) is arranged to: - receive the detection signal; - determine whether the detection signal satisfies a predetermined additional criterion; and - provide a signal if a predetermined additional criterion is met to indicate that no duct is supplied in the hole. Petition 870260035882, dated 04 / 16 / 2026, page 17 / 18 5 / 5

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