Abstract: A magnetic flowmeter in which a fluid to be metered is conducted through a ceramic spool coaxially supported within a cylinder casing to define an inner chamber. Mounted within the chamber at opposing positions on a magnet axis perpendicular to the longitudinal flow axis of the spool are a pair of electromagnets to establish an electromagnetic field in the spool whose lines of flux are intercepted by the fluid to induce a voltage therein. Interposed between the electromagnets and the outer surface of the spool and conforming to and secured to this surface are a pair of flexible printed circuit boards which are so printed as to define capacitance metering electrodes at diametrically-opposed positions on the spool on an electrode axis at right angles to the magnet axis and at right angles to the longitudinal flow axis, whereby the voltage induced in the fluid is picked up by these electrodes to produce a signal which depends on the flow rate of the fluid.

Abstract: A magnetic flowmeter which includes a spool formed by a metallizable ceramic whose dielectric constant is at least 25 through which the fluid to be metered is conducted. The outer surface of the spool is metallized in its central region to define a pair of capacitative metering electrodes at diametrically-opposed positions, an electromagnetic field being established within the spool whereby when the flowing fluid intercepts this field, an emf is induced therein to produce a signal at the metering electrodes which is a function of flow rate. Overlying each metering electrode and projecting from the spool is a ceramic block whose outer surface is metallized to define a shield electrode which covers the metering electrode.