Some New Developments in Fluidic Circuit Design

Abstract

This paper presents several new developments in fluidic circuit design. The use of orifices and capillaries, as input and feedback resistors, and vice-versa, in an operational amplifier circuit is shown to result in a scaler whose gain varies either directly or inversely in proportion to kinematic viscosity. When operating on a temperature sensitive gainblock this scalar can be used to compensate for the effects of variable ambient temperature. The orifice formed by the space between a jet and a solid wall is a pressure sensitive resistance that is used as the controlling element in a gain changer and an automatically null-balanced Wheatstone bridge. In a novel use of a laminar proportional amplifier (LPA), the nonlinear saturation characteristic is used to linearize inversely nonlinear sensor and circuit outputs. Finally a set-point pressure sensor, that is a highly asymmetric LPA, is described that develops a high differential output pressure as a function of power jet pressure which can be some set-point pressure. By using this device as a pressure sensor, an ultra-quiet, high suppression performance pressure regulator has been built and demonstrated.