Liquid flow sensing device

摘要

A liquid flow sensing device which incorporates a flow sensor having a liquid flow passage through which liquid can flow. A first electrode is disposed with a first wall of the flow passage such that the electrode extends about a portion of the flow passage. A second electrode is disposed with a second wall of the flow passage in that portion of the flow passage about which the first electrode extends. The first and second electrodes are so disposed that at least portions of the electrodes are in an opposing disposition. Electronic circuitry is coupled to the electrodes and in use of the device electronic detection circuitry detects a varying capacitance between the electrodes as the amount of liquid flowing through the flow passage varies. The flow sensing device is particularly suited for sensing milk flow in apparatus for the machine milking of animals. The sensing device includes a switching arrangement operable in response to detected liquid flow to open and close the flow passage and actuate a vacuum operated ram to remove teat caps from a milking animal.