Temperature Independent Fluidic Resistive Circuits and Concepts

Abstract

This paper discusses series and parallel topologies of orifices and capillaries as fluidic resistors and the way that they relate to temperature sensitivity and temperature compensation. Examination of a laminar flow nozzle, as typically found in a laminar proportional amplifier (LPA), shows that it may be represented by a parallel combination of an orifice and a capillary. As a result a nozzle has inherent temperature insensitive properties that allow temperature independent operation of such laminar fluidic devices as pressure controlled oscillators. It is shown that one may design a constant resistance, within ±0.1 percent, for changes in environmental temperature of ±20°C when air is the working fluid.