Patent ID: 6422094
Filing Date: 2002-07-23
Classification: G01F,G01N

Abstract:
A method for determining a flow rate or molecular mass of a liquid media or a gaseous media, comprising the steps of:emitting an ultrasonic pulse in a first direction from a transmitter in a flowable media; running a time duration which is slightly shorter than a known transit time of said ultrasonic pulse in a static medium of said flowable media, said step of emitting said ultrasonic pulse and said step of running said time duration commencing simultaneously; discharging a capacitor, to which a voltage is applied, commencing with a constant current intensity in said flowable media, said step of discharging said capacitor commences after ending of said time duration; terminating said discharging of said capacitor, when said ultrasonic pulse is registered in a receiver for receiving said ultrasonic pulse, while continuing to apply voltage to said capacitor; determining a discharge time by measuring said voltage still being applied to said capacitor; determining a first-direction transit time by adding together said time duration and said discharge time; determining a second-direction transit time by adding together said time duration and said discharge time in a second direction, said time duration and said discharge time in said second direction being determined by repeating said steps for determining said first-direction transmit time, said second direction being an opposite direction of flow of said flowable media from said first direction; and, calculating said a flow rate or molecular mass of a liquid media or a gaseous media from a difference between said first-direction transit time and said second-direction transit time.