Theory of magnetic flowmeter with potential distribution over conducting pipe wall.

Magnetic flowmeters should have nonconductive internal walls to prevent induced electromotive force from shunting. Most of commercial flowmeters are lined by insulating material. The lining material limits applicable temperature range of measured fluid and also reliability of meters. The authors' have already shown that the lining can be substituted by the wall potential formed by applying electric current externally. The principle of the proposed magnetic flowmeter is to keep the potential distribution over the inner wall almost identical to the flow induced potential in the liquid so that no current flows across the boundary between fluid and wall. Then the output signal becomes equal to that of conventional magnetic flowmeters. In this article, the proposed magnetic flowmeter is theoretically analyzed. (from authors' abstract)