Abstract: A pressure gauge fabricated from directly welded pieces of dissimilar metals. The gauge includes a casing, a tubular socket, and a Bourdon tube. The casing is fabricated of stainless steel and has an aperture with a flange. The socket is fabricated of aluminum bronze and is positioned within the aperture and flange in line contact therewith. The tubular socket also has a bore. The Bourdon tube is fabricated of stainless steel and is positioned within the bore in line contact therewith. Single weld lines exist along the lines of contact between the casing and the socket and between the socket and the Bourdon tube as caused by welding without a filler or insert material operatively associated with the single weld lines.

Abstract: A Bourdon tube adapted for connection to a source of fluid pressure operates both a mechanically driven gauge pointer and an optical-electronic transmitter for providing operatively parallel output signals corresponding to values of pressure incurred by the fluid source. Simultaneously operative from the displaceable end of the Bourdon tube are both a mechanical movement for effecting amplified displacement of the pointer relative to a dial plate and an opaque vane displaceable within the transmitter between a photoemitter and a pair of photosensors. Circuitry in the transmitter responsive to discrete changes in light interruption between the vane and one of the photosensors emits a signal current corresponding to the pressure value at any given position of the vane.

Abstract: An improved solid front casing for a pressure gauge that is readily field converted from a dust-tight to either a hermetically sealed air-tight or hermetically sealed liquid-tight construction. A flexible closure element is axially supported over a rear opening in the case by a threaded connection with threads formed in the case peripherally surrounding the opening. For either hermetically sealed air-tight or liquid-tight service a self-threaded closure element is replaced by a flexible diaphragm of controlled spring rate axially clamped by a threaded backup ring. Temperature induced volumetric changes imposed on the liquid fill or air fill are compensated for by the spring rate of the diaphragm. In the event of an overpressure occurring internally of the casing the diaphragm can escape from its clamping relation for affording pressure relief.

Abstract: An improved construction for securing the connecting link from the free end of a Bourdon tube to the segment gear in the geared movement of a pressure responsive instrument. An elongated flat spring clip, recessed in its center portion, has one open end from which it is longitudinally slotted inward. The opposite end is screw tapped for acting as a nut to receive a screw fastener. By a slip fit insertion of the spring clip over a controlled recess on the segment shaft, the clip is held in place in a controlled tensioned grip for captivating the nut at the fastener location of the segment gear. Should it be necessary to shift the fastener location for purposes of calibrating the instrument, the spring clip is finger slideable for relocation as required.