Basics of Fluidic Oscillation
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Transcript of Basics of Fluidic Oscillation
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Basics of Fluidic Oscillation?
Fully electronic, there are no moving parts
Improved reliability, less maintenance
Technology ideally suited for Commercial & Light
Industrial Applications: Rotary Alternative
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Fluidic Oscillation
Inlet
Flow
Tranquilizer
Jet Formation
Nozzle
Oscillation
Chamber(1) (3)
(2)
l Described in 3 elements
Flow Tranquilizer
Jet Formation Nozzle
Oscillation Chamber
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Oscillation Chamber
l An obstacle in the chamber is used
to control the fluid feedback paths.
l As the jet is bent to one side of
the cavity a pressure node isformed. This creates a difference in
pressure either side of the jet and
hence a force is exerted on the jet.
Obstacle
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Oscillation Chamber (cont.)
Obstacle
l The force causes the jet to bend to the
other side of the cavity where the
same effect will be seen.
l This oscillation only depends on the
volume of gas passing through the
nozzle. One oscillation cycle will
represent a characteristic volume of
gas.
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Sensor Technology
Sensors
l Thermo resistive sensors detecting changes in thermaltransfer to the gas.
l Common mode (K, r and Cp) rejected by sensor pair.
R1
R2
V
Sensor Resistance
R = R1 R 2
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Self cleaning
l The dimensionally sensitive zones of
the meter are the areas that see the
highest flows.
Nozzle Exit
Pressure Node Trap
Obstacle Cavity
l Abrasion resistant due to particlesuspension
Obstacle Cavity
Pressure Node Trap
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Key Features of Fluidic Oscillation
Static Metrology: DOES NOT LOCK UP!
No moving parts to replace due to wear
No chance of failure due to aggressive materials in the gas
Solid state meter easier to install (no leveling, wont bind)
Can be over driven with no ill effects
No oil
Quiet
Improved Operation & Maintenance
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Key Features of Fluidic Oscillation
400:1 Dynamic Range
fM 2
+/ .5% 9000 to 300 cfh
+/ 1% 300 to 60 cfh
+/ 2% 60 to 22 cfh
Extended Accuracy
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Rotary Comparison
95
96
97
98
99
100
101
102
0 1500 3000 4500 6000 7500 9000
FLOW RATE (cfh)
ACCURACY%
11M
3M 5M 7M
fM2
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Pressure DropDattus fM2 Pressure Drop in Gas
0
1
2
3
4
5
6
7
8
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Flow Rate (cu.ft./hour)
PressureLoss(In
chesw.c.)
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Applications
l Fluidic Oscillation is bestsuited for measurement
applications where pressure is available
Upstream of the regulator: capacity of 9000 acfh is
multiplied by pressure factor (3 x greater than 3M rotary)
On pounds delivery: where 5 w.c. drop is not an issue
l Meter potential is limited to design specifications for
pressure drop when measurement occurs atatmospheric conditions
1 drop allows only 3871 acfh capacity
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Functionality
l Market availability as:
Basic Metrology
Electronic Temperature Corrected
Full PTZ Correction
Programmable Fixed Factor Index
Instant Flowrate Display
Communications Capability
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Maintenance Requirements
l Battery Change
10 years: basic
l Accuracy verification
Sonic nozzle, bell or Model 5 transfer prover
Differential pressure test
Standard instrument calibration