AVF7000 Operation Manual
OP7000.1.1.7.R12ENG
3
1. Flowmeter Check
A. Check the overwrap first, if any damages occur, contact ALIA Customer Service Center at once.
B. Confirm whether the instrument has been damaged or its spares are lost.
C. It’s recommended that you read the manual thoroughly, once you have any quires, please email or fax to ALIA
technical department.
D. Ensure all the specifications of instrument are in a normal state.
E. Power on to check whether the LCD screen operates normal.
F. Proper installation is required.
G. Install flowmeter and pipeline under installation instructions.
H. Connect wires and specially attention on whether they have been shielded or grounded.
I. Power on and check whether there is any current leakage (mind your own safety), then if it doesn’t display any flow
rate, please follow steps above again, particularly wiring, power supply and grounding. If problem remains, please
contact ALIA Technical Support center or local agency.
2. Product Overview
Based on Von Karman vortices theory, AVF7000 can be used to measure liquid, gas and steam, even liquid that has
slight particles inside or turbid liquid. It’s widely used in industries such as petroleum, chemical engineering, pharmacy,
paper making, metallurgy, electricity, environmental protection and food.
3. Working Principle
ALIA AVF7000 is newly stress-type flowmeter that’s based on von Karman effect. It’s made up of a whole body whose
internal diameter and nominal diameter are the same and a triangular bluff body inside. Flow will alternately generate
vortices when passing by a bluff body. The periodic shedding of eddies occurs first from one side and then from the
other side of a bluff body (vortex-shedding body), is called "Karman vortex street” whose frequency is proportional to the
flow velocity.
Vortices at both sides cause pressure pulsation, making probe to generate alternation stress. The built-in electronic in
probe generates electric charge due to alternation press. And amplifier transmits them into pulsating output signals
which are equivalent to vortex shedding frequency.
Sensor
d
F=St v/d
F—frequency of vortex shedding (numbers) hz
d—width of bluff body
v—fluid velocity
St—Strouhal number, dimensionless
The actual width of a bluff body within a specific vortex meter is fixed and a function of Reynolds, therefore, a constant.
In linear range, from detected frequency F, pipe’s velocity is known, then volumetric flow. The relationship between
frequency and volumetric flow is defined as below:
Q=3600 F/K
K: factor
F: frequency
Q: fluid volume under actual condition (m3/h)
