Current-to-pressure transducers

Apparatus for governing the valved condition of a supply of fluid in accordance with electrical control signals, including a passageway communicating with said supply of fluid, and input terminals at which said control signals are impressed, comprising:

• an armature angularly movable about a support axis, valve means having a stationary nozzle communicating with said passageway and disposed for throttling by said armature which is variable with angular orientation of said armature about said axis, an electromagnet including stationary electrical winding means energized from said terminals and inductively associated with a stationary core of magnetic material and driving magnetic flux therethrough and across a magnetic gap between nearby ends of said core, and taut filament means supporting said armature for adjustable torsionally restrained angular movements about said axis between spaced relatively stationary mounts, said taut filament means comprising a single-length filament held taut between said mounts, at least one of said mounts being angularly adjustable to regulate torques experienced by said filament about said axis, said armature being bonded to said filament between ends of said filament, said armature having thin magnetic material thereof disposed in proximate overlapping flux-shunting relation to said ends of said core and said gap therebetween, whereby said armature simultaneously experiences torques about said axis caused by said taut filament means and by fluid impinging upon it from said nozzle and by forces of magnetic interaction between its said thin magnetic material and said stationary core.

A current-to-pressure transducer which bleeds fluid pressures from a branch line connected to a pneumatic source through a restriction to establish a control pressure responsive to electrical currents characterizing a sensed condition, comprising:

• a base having a fluid port in communication with the said branch line;
• a nozzle support bracket on said base having an interior fluid passageway communicating with said port and at least one cylindrical bore therethrough intercepting said passageway;
• a spool-type nozzle member fitted within said bore and having a longitudinal fluid path therethrough communicating at an outer end with a nozzle opening and with said interior passageway intermediate its ends;
• O-rings maintaining said spool-type nozzle member sealed within said bore and allowing axial movements thereof which adjust valving positions of said nozzle opening externally of said bracket;
• an elongated and relatively lightweight one-piece armature of relatively thin and flat-sided material having relatively high magnetic permeability;
• an adjustable taut-band suspension mounting said armature for angular movements about an axis transverse to the direction of its elongation and with a first flat side surface thereof disposed adjacent said nozzle opening to act as a flapper valve, said suspension including a narrow flat metal band fixed with said armature along said axis, and spaced mounts on said base holding said band in tension along said axis and angularly adjustable to develop elastic torsional restraints in said band about said axis;
• electromagnet means having a winding connected for electrical excitation by the said electrical currents and inductively associated with a gapped core of magnetic material and driving magnetic flux therethrough and across a magnetic gap between nearby ends of said core, said ends of said core having pole surfaces which are substantially flat and coplanar;
• and means mounting said electromagnet means on said base in substantially stationary relation thereto and with said pole surfaces of said ends of said core overlapped by a closely-spaced second flat side surface of said armature.