초록 ▼

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 sec

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.

대표청구항 ▼

A liquid flow sensing device comprising: a flow sensor having a flow passage through which liquid can flow, said flow passage having a first wall and a second wall, said flow sensor comprising a body having an annular space therein and into which opens an inlet whose cross-sectional area is substant

A liquid flow sensing device comprising: a flow sensor having a flow passage through which liquid can flow, said flow passage having a first wall and a second wall, said flow sensor comprising a body having an annular space therein and into which opens an inlet whose cross-sectional area is substantially the same as the cross-sectional area of said annular space, said body having an outlet coaxially disposed with respect to said inlet, said annular space being formed at least in part by said first wall and said second wall and disposed such that the axis of said annular space is at substantially right angles to the axis of said inlet and outlet, a first electrode disposed with a first wall of the flow passage so as to extend about a portion of the flow passage so as to extend about a portion of the flow passage, a second electrode disposed with a second wall of the flow passage in that portion of the flow passage about which the first electrode extends such that a least portions of the electrodes are in an opposing disposition, electronic detection means coupled to said electrodes for detecting a varying capacitance between the electrodes as the amount of liquid flow through the passage varies and flow passage closure means comprising a diaphragm mounted with said body, said diaphragm having a first surface which can sealingly close said annular space such that the fluid flow to said outlet is prevented, and a second surface exposed to a chamber in which a sub-atmospheric pressure can be established.