Abstract: A multicoil tube type pressure gauge arranged for direct drive of the gauge pointer and for safely handling overpressure in the event of Bourdon tube rupture comprising a casing of round configuration defining a planar upright main chamber, with the casing being indented rearwardly adjacent the axial center of the gauge to define a supplemental chamber, a mounting plate that is common to all the working parts of the gauge secured to the gauge casing over the supplemental chamber and mounting cantilever fashion a tubular spool journaling the gauge pointer shaft, a multicoil Bourdon tube encircling the spool having its sealed end secured to the shaft within the supplemental chamber, and a pressure connection fitting in the form of a connection block anchored to the mounting plate and having a pressure cavity to which the Bourdon tube other end is sealingly secured with its bore in communication with the fitting pressure cavity, with the Bourdon tube direct driving the gauge pointer shaft; the working parts of t

Abstract: A fluid pressure gauge comprises a unitary, sealed, U-shaped hollow tube (12) with an electrically conductive ribbon (14) stretched between the ends of its arms (18). Fluid pressure applied to the interior of the tube via an inlet (24) on the axis of symmetry tends to straighten the tube, thereby varying the tension in the ribbon. The tension, and thus the pressure, are sensed by measuring the natural frequency of electromagnetically-maintained transverse vibration of the ribbon. Adjustment of the initial tension of the ribbon enables temperature sensitivity of the gauge to be reduced. One arm of the tube can be omitted, the ribbon being connected chordally across the curved portion and the pressure being applied through the remaining arm, or alternatively the tube can be serpentine in form.