Abstract: A pair of electrodes and a pair of magnetic poles are mounted to a resin-made conduit body with each of those parts partly exposed to the lumen. The magnetic poles are formed by an electrically conductive material and serve also as ground electrodes by being connected to ground. The magnetic poles serving also as the ground electrodes are positioned in the same plane as signal electrodes with a result that the distance on the axis of the conduit between the signal electrodes and the ground electrodes is fixed, more precisely, the distance is zero, so that the zero point of the electromagnetic flowmeter is stabilized. The magnetic poles, mounted to the conduit body, are separated from the yokes on which coils are wound, and both the magnetic poles and the yokes are detachable.

Abstract: An electromagnetic flowmeter includes a cylindrical flow path, an even number of magnetic poles disposed on the periphery of the cylindrical flow path by equally dividing the circumference thereof, a plurality of cores having one ends respectively being in contact with the even number of magnetic poles and extending outwardly radially with respect to the cylindrical flow path, a plurality of coils respectively wound about the cores for exciting the cores so that respective adjacent cores exhibit opposite polarities to each other, an outer yoke having a ring shape for connecting the other ends of the cores to form a magnetic circuit, and a plurality of electrodes disposed respectively at intermediate points of respective adjacent magnetic poles and having one ends being in contact with a fluid in the cylindrical fluid path, wherein the even number of magnetic poles are corresponding in number to the cores, to the coils, and to the electrodes, and the number is equal to four or larger.