Abstract: A method for inhibiting metal corrosion in once-through water systems entailing the use of a pyrophosphate-zinc composition.

Abstract: A cavity tuning assembly for use in a tuned cavity having provisions for coarse tune adjustment and fine tune adjustment for changing the frequency of the cavity's resonance. Coarse tune adjustment is obtained by sliding an unthreaded cavity tuning rod of the cavity tuning assembly up and down through a threaded bushing to obtain rough tune whereupon the unthreaded rod is locked into place by way of a knurl nut compressing a split end portion of a shaft lock screwed onto the threaded bushing into friction engagement around the cavity tuning rod. Fine tune adjustment is obtained by rotating the unthreaded rod into engagement with the shaft lock and the threaded bushing causing the threaded bushing and engaged structure to screw into or out of a pipe reducer to obtain fine tune which is then locked against the threaded bushing by a lever lock nut.