The measurement principle of the transit time difference method of the ultrasonic flowmeter is presented. The hardware structure and realization method are introduced. The software function and work mode are overviewed. In order to enhancing flowmeter's precision and stability a Xilinx CoolRunner CPLD and a Texas Instruments microcontroller from MSP430 family are applied in high precision timin...

Experimental study of multi-path ultrasonic flowmeters measurement accuracy in complex flow fields was carried out in the water flowrate standard facility of National Water Large Flowrate Measurement Station. Several muti-path ultrasonic flowmeters with different path arrangement were studied. The flow disturbances were created by bend, tapered pipe, diverging pipe and butterfly valve. By study...

BACKGROUND Greater occipital nerve block is used in the treatment of headaches and neuralgia in the occipital area. We evaluated the efficacy of ultrasonic doppler flowmeter-guided occipital nerve block in patients experiencing headache in the occipital region in a randomized, prospective, placebo-controlled study. METHODS Twenty-six patients, aged 18 to 70, with headache in the occipital reg...

Our objective was to validate the use of an ultrasonic transit-time flowmeter for the measurement of portal blood flow (PBF) in sheep. Data recorded with this technique were compared with those obtained with an indicator dilution method, and probes were calibrated in vivo. Wethers were fitted with catheters in the portal, jejunal, and ruminal veins and in a mesenteric artery. Ultrasonic flow pr...

An ultrasonic flowmeter could be advantageous over a differential pressure pneumotachograph having a constant error in varying conditions. The in vitro accuracy of ultrasonic tidal volume (VT) estimates for ventilated infants were evaluated. Flow linearity and frequency response were tested, as was the influence of humidity and oxygen content on the accuracy of VT estimates. The linearity was w...

Ultrasonic (US) flow meters are devices for a fluid measurement using the ultrasonic principle. Current research project dealing with developing flowmeter an innovative channel shape. Previously work was aimed to topology optimization CFD methods. The final prototype has be analyzed experimentally verify velocity profiles in US section. obtained this region necessary as input sensor data evalua...