Feasibility of Utilizing Air Gapped Toroidal Magnetic Cores for Detecting Pulse Wave in Radial Artery

The feasibility study of utilization of air gapped toroidal magnetic cores for monitoring changing volume of pulsating blood in artery is shown in this paper. The changing impedance of conductive path of blood is represented by a single solid core copper wire, connected to a closed circuit with potentiometer. Commercially available toroidal magnetic cores with two different shapes of custom implemented air gaps and desired number of windings were used to induce current in copper wire. The theoretical expectation of the possibility to focus most of the reluctance of emerging magnetic field into the air gap was experimented. The location of conductive path relative to the implemented air gap was determined to be critical and the best outcome was gained when the copper wire was passing through the center of toroidal core instead of the gap itself. Also, the shape of the air gap was determined to acquire important role related to the location of the conductive path – as the flux fringing is appearing not to significantly affect the magnitude of induced current. The potentiality of monitoring pulse wave by positioning the air gap of toroidal core noninvasively onto the location of radial artery in forearm was concluded not to be feasible with the used setup. The results of on-desk measurements were validated with finite element method simulation of magnetic flux density distribution.