Doppler flowmeter
A Doppler flowmeter impulses an ultrasonic fixed-frequency signal obliquely into a slurry flowing in a pipe and a reflected signal is detected after having been scattered off of the slurry particles, whereby the shift in frequencies between the signals is proportional to the slurry velocity and hence slurry flow rate. This flowmeter filters the Doppler frequency-shift signal, compares the filtered and unfiltered shift signals in a divider to obtain a ratio, and then further compares this ratio against a preset fractional ratio. The flowmeter utilizes a voltage-to-frequency convertor to generate a pulsed signal having a determinable rate of repetition precisely proportional to the divergence of the ratios. The pulsed signal serves as the input control for a frequency-controlled low-pass filter, which provides thereby that the cutoff frequency of the filtered signal is known. The flowmeter provides a feedback control by minimizing the divergence. With the cutoff frequency and preset fractional ratio known, the slurry velocity and hence flow will also be determinable.
- Assignee:
- Dept. of Energy
- Patent Number(s):
- US 4413531
- OSTI ID:
- 5248965
- Resource Relation:
- Patent File Date: Filed date 13 Nov 1981; Other Information: PAT-APPL-321345
- Country of Publication:
- United States
- Language:
- English
Similar Records
Doppler flowmeter
Experience with ultrasonic flowmeters
Related Subjects
FLOWMETERS
DESIGN
DOPPLER EFFECT
FREQUENCY CONTROL
PIPES
SLURRIES
ULTRASONIC WAVES
VELOCITY
CONTROL
DISPERSIONS
MEASURING INSTRUMENTS
METERS
MIXTURES
SOUND WAVES
SUSPENSIONS
440105* - Radiation Instrumentation- Radiometric Instruments- (-1987)