Yokogawa Electric Works, Ltd.

Toshio Aga

Ichizo Ito

Tetsuo Ando

Takehiro Sawayama

Yoshio Kurita

Katsumi Takahashi

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.

Force detector

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.

Flow metering apparatus

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.

Vortex flow meter

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. The passageway means communicate fluid fluctuations past a flow detector to measure the frequency of vortex production and thereby determine the velocity of the fluid stream. Further improvement of the correspondence of vortex production rate with flow velocity is attained by dimensioning the area A of the passageway opening in relation to the area Ao of the rectangle side containing the opening so that 0.3.ltoreq.A/Ao&lt;1. The length l of the passageway opening in the axial direction of the vortex generating element is related to the inside diameter D of the pipe in which the element is placed so that 0.5.ltoreq.l/D&lt;1. Finally, the rectangle height h is related to the inside diameter D of the pipe so that 0.2.ltoreq.h/D.ltoreq.0.35.

Growing community of inventors

Musashino, Japan

Toshio Aga