Flow characteristics in circuits using three-port modulating control valves

Abstract

This work has sought to identify the nature of the total flow characteristic in circuits controlled by three-port modulating valves. A theoretical model has been developed and compared with a small family of three-port control valves. The influence of valve signal/flow hysteresis error has been quantified, though no account was taken of valve wear. Good potential for the use of control valves as passive flow monitors has been identified, though further work is required to evolve a practical solution for this. The agreement between experimental data and theoretical results is encouraging, suggesting that a model has potential for use where measurements of valve performance are unavailable. The influence of signal/flow hysteresis was found to be insignificant.

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