STRIPPER FOR BUBBLE-FREE TENSIOMETRY

Unwanted formation of air bubbles in the liquid water inside soil wate r tensiometers has always been a major nuisance afflicting this simple , fast, and accurate device. The stripper, a plastic wall (usually jus t a tubing wall) between the tensiometer water and a wet vacuum (conta ining some droplets of liquid water), strips any dissolved air out of this water. Bubbles cannot grow, they will shrink and disappear, unles s the water pressure inside the tensiometer is less than the vapor pre ssure of water (at the ambient temperature). Choices of desirable plas tic materials and other considerations are based on 7 yr of developmen t and employment of this method.