Abstract: A device for measuring the displacement of stems of valves having a spindle coupled to a stem of a valve and provided with two inductive pickups; each inductive pickup is formed by a fixed part and a movable part constituting a variable inductor, which, following a displacement of the stem and a rotation of the spindle coupled thereto, generates an inductance variation of the electric circuit associated thereto; electronic excitation and detection means are adapted to convert the inductance variations into a pair of digital signals whose difference is indicative of the displacement of the stem.

Abstract: Method for manufacturing a pressure-measuring device comprising a diaphragm of semiconductor material having a resonating element fixed thereto, said diaphragm being exposed to the pressure of a process fluid, wherein it comprises the following phases: i) machining a multilayer semiconductor material to obtain a diaphragm having on the upper side a resonating element, an excitation element and a detection element for measuring the pressure applied to said diaphragm; ii) machining a semiconductor material having one or more layers to obtain a support having a pressure port for the flow of the process fluid; iii) making a bond between the lower side of said diaphragm and the upper side of said support.

Abstract: An improved device for measuring pressures, comprising a silicon membrane or diaphragm which is exposed, on its two faces, to two pressures whose difference is to be measured. A resonant element is provided on one face of the diaphragm, which is treated by selective chemical etching, and is mechanically coupled to the diaphragm so that its resonance frequency varies as a consequence of the deformation undergone by the diaphragm.