Arrangement for measuring liquid nutrient flows in tree trunks - uses passive or active heating to constant temp. and measures delivered power as measure of flow rate

摘要

The arrangement for measuring the quantity of liquid nutrient transported through the xylem in a tree trunk heats the measurement region to a constant temp. above the unheated region's temp. The delivered heating power is measured to give a measure of the instantaneous flow rate and regulated. A passive heater can be used with electrodes (21-25) in the trunk or ultrasonic transducers operated with a defined frequency or voltage with the xylem forming the variable heating resistance. Alternatively, an active heater can be used. A slow, overshoot-free controller is used with temp. sensors and voltage decoupling. USE/ADVANTAGE - Accurate continuous measurement is achieved in trees in natural locations.