Abstract: A pressure sensor which uses a tapered shearing piezoresistance type gage to obtain high output. The components are fabricated to produce a surface of the gage which is protected by an oxide film which is turned into phosphorated silicate glass; a sensor surface which has an MOS structure with a silicon substrate; oxide film and polycrystalline silicon film; with the polycrystalline silicon film being fixed at a potential higher than maximum potential generated by the shearing gate, and the surface of the piezoresistance element are where P-type impurity is diffused to a low density being inverted. Thus, the shearing gage is operated substantially in a bulk, and influence due to impurity ion from an external source is removed. Furthermore, the pressure sensor buffers stress arising within the sensor by use of the polycrystalline silicon film, prevents occurrence of local stress by keeping the passivation film from dropping in surface level, thereby minimizing zero offset of the output and drift.

Abstract: A force detector for detecting a force directly as a stress is disclosed which includes a piezoelectric unit for detecting a stress, a vessel for housing the piezoelectric unit, and a seal member for sealing the piezoelectric unit firmly and integrally in the vessel.

Abstract: A flow metering apparatus is disclosed which includes a dust in which a fluid to be measured flows, a pillar-shaped vortex generator inserted into the duct, and a force detector fixed firmly to the vortex generator substantially in an integrated manner, and capable of directly detecting an alternating force applied to the vortex generator due to Karman's vortex generated by the vortex generator, and converting the alternating force into an electric output signal.

Abstract: A vortex flow meter produces Karman's vortices in a fluid to be measured and a piezoelectric sensor develops a vortex signal therefrom which is proportional to the flow velocity of the fluid. The output signal of the sensor is applied to a charge amplifier and a low pass filter coupled thereto which functions to a predetermined signal amplitude for limiting low and high frequency noise and stabilizing the gain of the system within the vortex frequency measuring range. The output signal is converted by a logic circuit to a pulse signal of vortex frequency and then converted to a DC signal for transmission to an indicator or a receiver.

Abstract: A flow metering apparatus of the type having a vortex generating element with a generally elongate cylindrical shape placed in a stream of flowing fluid so as to produce Karman's vortices at a rate proportional to the velocity of the flowing fluid, with means for detecting the rate of production of vortices to give a linearly related measure of fluid velocity. To improve the correspondence of vortex production rate with flow velocity over wide conditions of flow, the element is formed with a rectangular cross-section in which the depth d along the direction of flow and the height h across the direction of flow are arranged in a ratio d/h of between about 0.5 and 0.9 and preferably in a ratio of 2/3. In the vortex generating element, passageway means extend between openings in the two opposed rectangle sides which are aligned with the direction of flow.