Abstract: A gauge for the measurement of both pressure and temperature of a fluid includes a dial plate having pressure and temperature graduations thereon, a first Bourdon tube for measuring pressure and a second Bourdon tube for measuring temperature. The Bourdon tubes are of conventional multiturn spiral construction, each having an open end which communicates with a source of pressure and a closed free end that rotationally responds to changes in pressure within the Bourdon tube. The open ends of the Bourdon tubes are mounted in fixed relation to the dial plate. Attached to the free end of each Bourdon tube is a direct coupled indicating pointer which is rotationally displaceable relative to corresponding graduations on the dial plate. A temperature responsive bulb is connected via a capillary tube to the open end of the second spiral Bourdon tube and forms a closed temperature sensing system therewith.

Abstract: A bourdon tube for gas and liquid-filled thermometers and pressure gauges constructed by edge welding two strips of isoelastic nickel alloy to form a wall to wall low volume bourdon tube that exhibits a low ambient temperature effect and improved rangeability over all existing bourdon tubes used for temperature and pressure measurement and control.