Thermoelectric probe apparatus for tissue fluid flow measurement

Claim 1

A miniaturized thermoelectric probe system for steady state fluid flow measurement comprising: A. a first elongate probe having a fine, miniaturized terminal end face and comprising first and second miniature thermistor beads, said beads being separately positioned on the end face, and a first layer of insulating material encasing the thermistor beads; B. a second elongate probe having a fine, miniaturized terminal end face and comprising a third miniature thermistor bead, said third bead being positioned on the end face, and a second layer of insulating material encasing the said third thermistor bead; c. a bridge circuit connecting the first and third thermistor beads in series in one arm thereof and including feedback means for providing heating current to the second thermistor bead in response to bridge imbalance; D. means for sensing current and voltage changes through said second thermistor bead and combining the current and voltage changes to yield an indication of the power consumed in heating the second thermistor bead; and E. electrically responsive readout means responsive to the said sensing means.