ELECTROMAGNETIC FLOW SENSOR

An electromagnetic flow sensor for an electromagnetic flow meter (201) is disclosed. The sensor comprises a body (204) or frame, a flow passage (252) through the body or frame, at least part of a magnetic circuit (248, 295) supported by the body or frame for applying a magnetic field across the flow passage, and at least first and second electrodes (298) supported by the body or frame, the at least first and second electrodes arranged to sense a voltage in response to a conductive fluid flowing through the flow passage. The at least part of the magnetic circuit comprises a central pole piece (172; 292) and outer pole piece(s) (173; 295) extending around the central pole piece and the passage so as to serve as a magnetic screen from an external magnetic field.