Vortex Flow Technology. Corporate Brand.
The acute angle and sharp straight edges of the top half of the diamond symbol represent Yokogawa’s cutting-edge technology while the gentle curvature of the bottom half represents the warm-hearted nature of Yokogawa’s people. By balancing these two elements, Yokogawa aims to contribute toward the realization of a thriving global society in much the same way as the sun. This property is reflected in the bright yellow of the diamond.
– Corporate trademark since October 1986
first Vortex meter
First 0.5 inch
Dual Sensor Designs
High Pressure Design
The analogy of a golf ball moving through the air is useful in describing vortex formation:
A slow moving putt barely displaces
the molecules of air
The higher velocity of a chip shot causes irregular eddies to form behind the ball
The velocity associated with a drive is
sufficient to cause a strong, regular
vortex formation behind the ball
Principle of Operation
Vortex formation in clouds blown by a mountain top is an example from nature of the vortex phenomenon
Light breeze - Laminar flow,
no vortices formed
NR = 0-5000
Stiff breeze - Transition flow,
irregular vortex formation
NR = 5000-20000
Strong wind - Turbulent flow,
regular vortex pattern
NR = >20000
When a flowing medium strikes a non-streamlined bluff object,
it separates, moves around the object and passes downstream.
At the point of contact with the object, vortex swirls separate from the
body on alternating sides. This separation causes a local increase
in pressure and a decrease in velocity on one side and a decrease
in pressure and an increase in velocity on the opposite side. The
alternating velocities generate alternating pressure forces on either side
of the bluff body. The frequency of these pressure changes is
proportional to velocity.
Differential Switched Capacitor
YEWFLO Shedder Bar
How Does It Work?
Flow hits the shedder bar, separates and due to the shape of the bar, forms vortices. The vortices create an alternating pressure differential across the bar. The bar is physically stressed toward the low pressure side of the bar.
A piezoelectric crystal converts a mechanical stress into an electrical pulse. The crystals are hermetically sealed and not in contact with the process.
The Karman vortex frequency “f” is proportional to the velocity ”v”. Therefore, it is possible to obtain the flow rate by measuring the Karman vortex frequency:
f = St (v/d)
where: f = Karman vortex frequency
St = Strouhal number (constant)
v = Velocity
d = Width of vortex shedder (constant)
“O” RING SEAL
INSULATOR (SHRINK TUBING)
SOLID METAL SHEDDER BAR
“O” Ring Seal
Solid Metal Shedder Bar
+/- 0.75% of reading (liquid)
+/- 1% of reading (gas, steam)
~Spectral Signal Processing
Bending moment of shedder bar in lift force direction
[Separation by SAF]
~ Spectral Signal Processing
The signal is split into individual sub-bands like the frequency spectrum display of an audio graphic equalizer. The band splitting filter also applies intelligent attenuation to linearize the amplitude vs. velocity charac-
teristic. Based on application information such as liquid or gas, flow span and density a predicted amplitude/sensitivity curve is computed. The results of the individual sub-band analyses are
compared to the predicted sensitivity curve. Finally a tight band pass filter is focused around the vortex flow signal.
Noise Ratio Setting
In digitalYEWFLO the signal processing circuitry is fully digitized. This permits signal
processing which had been previously performed by analog circuits (such as an adder,
Schmitt trigger, and filter) to be incorporated into a gate array, resulting in reduced parts
and a downsizing of the converter.
Span: 15 m3/h (2 m/s)
Fluid: Water Size: 50mm Setting: Default
RTD embedded in
Built-in temp sensor
Steam mass flowrate calculation
Correct I.D. required
Self Centering (Recommended)
Problems occur if... gasket is too
small,gasket is deformed, has shifted
position, or if the mating pipe connection is
Vortex has come a long way over the year.
Use Vortex as another flow measurement solution. It really does Work!