Fluid leakport orifice structure

Abstract

A fluid signal comparator includes a flexible diaphragm clamped within a housing and defining a signal input chamber coupled to a signal source and an input/output chamber connected to an air supply and to a load. A leakport orifice unit includes a centrally located nozzle having a planar outer edge seat located in spaced parallel relation to the diaphragm. The diaphragm moves to create a pressure in the input/output chamber which balances the input signal force on the diaphragm. An output port is connected to the input/output chamber and to the load in the illustrated embodiment to transmit the pressure and/or flow to the load. The pressure of the input signal and of the stream acts on opposite sides of the diaphragm and positions the diaphragm relative to the orifice seat to create a restricted flow passageway having the necessary pressure drop to create a balanced pressure condition in the output chamber. The sealing land or seat of the nozzle includes a plurality of circumferentially distributed dished notches which break the planar sealing surface presented to the diaphragm and establish offset auxiliary flow paths within the restricted gap. The notches are of different cross-sectional areas and function to stabilize modulating movement of the diaphragm and essentially eliminate vibration of the diaphragm to produce a stable and audible-free pressure signal.