Ultrasonic flow meters are gaining wide usage in commercial, industrial and medical applications. Major benefits of utilizing this type of flowmeter are higher accuracy, low maintenance (no moving parts), noninvasive flow measurement, and the ability to regularly diagnose health of the meter. This application note is intended as an introduction to ultrasonic time-of-flight (TOF) flow sensing us...

An ultrasonic transit time flowmeter was tested over Reynolds numbers from 1000 to 100 000 in a calibration facility that generates gas flows with controlled temperature and composition. The gas mixtures were composed of air, nitrogen, carbon dioxide, water vapor, and argon, and the mixture temperature ranged from 290 K to 450 K. The test program was conducted to determine the sensitivity of th...

The blood flow teas measured continuously in the intact vortex vein of the anesthetized rabbit using an ultrasonic Doppler -flowmeter toith a frequency response of approximately 4 Hz. Blood flow correlated well ivith perfusion pressure (arterial pressure minus intraocular pressure). The intraocidar pressure was changed stepwise by perfusion from a saline reservoir, Tonometry teas performed tuit...

This year we celebrate 60 years since Shigeo Satomura published the first measurements of the Doppler shift of ultrasonic signals from a beating heart. He demonstrated that Doppler signals can be retrieved from heart movements when insonated with 3 MHz ultrasonic waves. Later, togheter with Ziro Kaneko, he constructed the first Doppler flowmeter to measure the blood flow velocities in periphera...

Phasic aortic flow velocity was recorded in two patients with pulsus alternans using a flow velocity probe connected to a Doppler ultrasonic flowmeter system. The variations in beat-to-beat peak velocity paralleled the variations in arterial and ventricular systolic pressures. This study provides direct evidence that stroke volume varies during this abnormal haemodynamic status. It is conceivab...