Detector for detecting the state of electrically non-conductive or substantially electrically non conductive fluid

Claim 1

A flow meter for generally electrically non-conductive liquid, comprising a transducer to generate an electrical signal responsive to the flowing state of said liquid therethrough, including a radiation source to ionize said liquid and first and second ionizing areas each having a pair of electrodes exposed to said ionized liquid and defining said respective ionizing areas, said first and second ionizing areas arranged in a flowing direction of said liquid; an amplifier having a high input impedance and a low output impedance and connected to said electrodes of said first and second ionizing areas; and electrically conductive shielding means to shield said transducer and said amplifier, characterized by that said transducer further includes a conduit by which said first and second ionizing areas are enclosed and into which said liquid is introduced so that it passes through one of said first and second ionizing areas and then through the other ionizing area, and that said amplifier together with its high impedance input side is disposed within the space between said conduit and said shielding means, with output lead means from said amplifier extending through and out of said shielding means for adaption to connection with an external circuit.