Lead screw actuated fluid gauge

In a pressure-responsive gauge of the type having a base, a balance beam, a fulcrum pivotally supporting said beam relative to said base, pressure-responsive means interposed between said base and said beam arranged to tilt said beam, a poise slideable along said beam to counterbalance the force of said pressure-responsive means, drive means for moving said poise, and a servo-motor arranged to actuate said drive means, an armature attached to one end of said beam, a differential transformer excited by said armature, an electric circuit including said transformer and said servo-motor functioning to move said poise to null said transformer and a read-out driven by said servo-motor, the improvement wherein said drive means comprises a lead screw parallel to the neutral position of said beam, means interconnecting said screw and said servo-motor, a carriage in threaded engagement with said screw, mounting means mounting said carriage for movement parallel to said beam, and transmission means for transmitting movement of said carriage to said poise, and wherein said guage further comprises temperature responsive means to compensate for temperature variations in a vertical sense comprising a spacer between said pressure-responsive means and said base of a different material than said pressure-responsive means, said spacer and said pressure-responsive means having dimensions and coefficients of expansion such that they expand to the same extent as said fulcrum, a clamp adjustably clamping said transformer vertically relative to said base, the materials of said clamp, armature and spacer being such that the position of the midpoint of said armature relative to the null point of said transformer remains fixed despite temperature variations.