| CPC G01F 1/584 (2013.01) [B67D 1/0888 (2013.01); B67D 1/1243 (2013.01); G01F 1/56 (2013.01); G01F 1/696 (2013.01); G01F 13/006 (2013.01); G01F 13/008 (2013.01); G01F 23/266 (2013.01)] | 20 Claims |

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1. A circuit for detecting a liquid flow through a duct of a tap for dispensing beverages, the circuit comprising:
an alternating signal source having a signal terminal arranged to provide an alternating signal to a first electrode of a capacitive element comprising two electrodes provided adjacent to the duct along at least part of a length of the duct and the alternating signal source further comprising a zero terminal;
a detection circuit arranged to be connected to the capacitive element for receiving an input signal from a second electrode of said two electrodes of the capacitive element and arranged to detect a signal amplitude value, the detection circuit being arranged to provide a detection signal based on the signal amplitude value at a detection terminal of the detection circuit;
an electronic digital processing circuit arranged to:
receive the detection signal;
determine whether the detection signal satisfies a pre-determined criterion; and
provide a flow signal if the pre-determined criterion is met;
wherein:
the detection circuit comprises a signal transformation circuit for transforming the input signal received from the second electrode, to provide a transformed signal having been transformed from a time domain to a frequency domain;
the detection circuit further comprises a convolution module that provides an output that is a convolution of the transformed signal with an auxiliary signal; and
the detection signal is based on the output of the convolution module,
wherein the detection signal is indicative of said liquid flow flowing through the duct.
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