Fluidic set point amplifier apparatus and method, and uses thereof

Fluidic set point amplifier apparatus comprising:

• a housing;
• said housing defining an inlet port communicating with a source of pressurized elastic fluid, an outlet port communicating with a source of reference pressure, and a flow path extending from said inlet port to said outlet port for communicating a flow of said elastic fluid therebetween;
• said flow defining a convergent-divergent (de Laval) nozzle having a convergent section leading from said inlet port to a throat section of minimum cross sectional flow area, and a divergent section extending downstream of said throat section to said outlet port;
• and an output signal port communicating with said throat section for providing a fluid pressure level output signal in response to a flow of elastic fluid in said flow path, whereby in response to a progressively increasing pressure differential between said inlet port and said outlet port said fluid pressure level output signal includes a progressively decreasing sub-reference pressure level followed by a progressively increasing sub-reference pressure level increasing to said reference pressure, and a progressively increasing supra-reference pressure level;
• which increasing sub-reference and supra-reference pressure levels are substantially linearly related to said increasing pressure differential between said inlet port and said outlet port and are substantially free of hysteresis.