VersaFlow Coriolis Flow Meter Cảm biến lưu lượng

VersaFlow Coriolis Flow Meter
VersaFlow Coriolis Flow Meter
1.
2.
3.
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5.
6.
Theory of Operation
Customer Benefits of unique Design Features
Application Examples
Sizing / Selection Criteria
Installation Considerations
Summary
Measurement by mass is the most
accurate method
• Mass is independent of:
• pressure
• temperature
• viscosity
• conductivity
•gravity
• Reactions are mass balanced
Mass provides the greatest
reproducibility!
Why Mass Measurement?
However installation, calibration and
maintenance of a scale or load cell is:
• Costly
• Difficult
• Time consuming

• Doesn’t allow continuous process
Commonly done in batches with
weigh scales or load cells:
VersaFlow Coriolis Flow Meter
High cost for instruments:
• Purchase:
$ 6,500 to $9,500 +
• Installation costs: $$$
• Commission costs: $$$
• Maintaining & calibrating $$$
55.6 Lb./Min
4 - 20 mA
Pulse out
Vortex Flow meter Pressure Temperature
Transmitter Transmitter
Flow Computer
To calculate Mass
Power
Supply
33.6 Lb/Min
Flow Computer
To calculate Mass
Power
Supply
4-20 mA
Output
Pulse
Output
Radiometric Density
Measurement

System
Magnetic
Flow meter
Power
Supply
Flow
Flow
Combining the uncertainty
of (3) separate instruments
Low mass flow accuracy:
+/- 1.5 to 2.5%
Conductive liquids
Non-conductive liquids
VersaFlow Coriolis Flow Meter
Combined Instrument Measurement
Turbine Meter
Densitometer
Flow Controller
VersaFlow Coriolis Flow Meter
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Direct mass flow measurement with Coriolis mass
flowmeters
z One flow meter allows multiple measured
values
z Mass flow & mass total
z Density & concentration
z Volume flow & volume total
z Temperature
z Reduces costs
z 1 Instrument

z Reduce cables/power consumption
z Increases accuracy/efficiency
z Simplified control
z Higher Safety Factor
z Easy to install & operate
z Highly accurate
VersaFlow Coriolis Flow Meter
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So what is the Coriolis effect?
z Discovered by Gaspar Gustav de Coriolis in 1835
z The Coriolis effect is an apparent deflection of a moving object in a rotating frame of
reference, sometimes attributed to a fictitious force “Coriolis force”
z Used to show effect of earth’s rotation on weather patterns
VersaFlow Coriolis Flow Meter
Coriolis principle
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Theory of Operation : Mass flow measurement
Consider a mass in a rotating system,
moving towards (or away from the centre
of rotation. The rotational velocity of the
mass is changed, due an acceleration.
To accelerate an object, a force must be
applied. This is the Coriolis force.
Fc acts on the particle, m,
with a resultant reaction Fr
Fr acts in the opposite direction
on the tube wall and can be measured as
a deflection in the tube rotation
Fc = m ( 2v
r

ω )
VersaFlow Coriolis Flow Meter
VersaFlow Coriolis Flow Meter
Midpoint
Tube without flow
Tube with flow
F
c
Flow
ω
Driver coil
F
c
Sensors A & B
• Tube is “damped” on inlet side: sensor A phase –
• Tube is “accelerated” on outlet side: sensor B phase +
Sensors
Driver
Outer cylinder
Inner cylinder or bridge
Connecting tube
VersaFlow Coriolis Flow Meter
Mass Flow = 0
Sensor A
Sensor B
Sensor A
Sensor B
Mass Flow > 0
Sensor BSensor A
VersaFlow Coriolis Flow Meter

Sensor A
Sensor B
Sensor A
Sensor B
Common signal processing
techniques are prone to
ERRORS when
disturbances are present.
Optimass uses
extremely High Sampling
Rate (5 kHz) & Digital
Signal Processing to
Minimize Errors caused
by Electrical and
Mechanical Noise
VersaFlow Coriolis Flow Meter
1 Hz
Frequency - Hz.
Digitally
Filtered
Sensor
Signal
Optimass uses Digital
Narrow Band Pass
Filtering:
Allows only 1 Hz to be
Analyzed. This method
provides Improved
Signal Quality for
highly reliable

measurements
8 - 20 Hz
Frequency - Hz.
Raw
Sensor
Signal
Traditional Filtering
Allows 8 - 20 Hz to be
Analyzed. This method
is Prone to Errors at
lower flows.
VersaFlow Coriolis Flow Meter
VersaFlow Coriolis Flow Meter
2π
1
f =
K
m
(1)
m = m
tube
+ m
fluid
m
fluid
= ρ
fluid
• V
tube
m

tube
, V
tube
= constant
K = Spring Stiffness
ρ =
K
f
2
V4π
2
-
m
tube
V
tube
(2)
VersaFlow Coriolis Flow Meter
Flow
Direction of Oscillation
f
Meter /
Size
Titanium SS318L Hastelloy
Air Water Air Water Air Water
CMxx- 06 316 301 374 361
CMxx- 10 402 367 419 394 439 415
CMxx- 15 507 436 573 514 574 517
CMxx- 25 619 488 701 589 693 586
CMxx- 40 571 415 642 509 633 506

CMxx- 50 539 375 550 435 582 453
CMxx- 80 497 349 502 378 492 369
Frequency shift of VersaFlow Coriolis 1000
Greater the shift (water to air), better the density measurement
VersaFlow Coriolis Flow Meter
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Fixed to tube using
epoxy adhesive,
bonded and oven-
cured
Theory of Operation 3: Temperature measurement
z Uses a PT 500 sensor mounted onto the outside of the measuring tube
z Also used for internal compensation
VersaFlow Coriolis Flow Meter
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z Volume is not a direct measurement
z It is calculated from the mass flow and density measurement
Volume flow rate = Mass flow rate /Density of product
Other measurements: Volume flow
VersaFlow Coriolis Flow Meter
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Other measurements
z All other measurements
z Concentration
z API Density
z Referred Density
z Velocity
z Are a combination or calculated from the prime measurements
VersaFlow Coriolis Flow Meter
1.

2.
3.
4.
5.
6.
Theory of Operation
Customer Benefits of unique Design Features
Application Examples
Sizing / Selection Criteria
Installation Considerations
Summary
21
How did we get here?
VersaFlow Coriolis Flow Meter
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Coriolis Designs
VersaFlow Coriolis Flow Meter
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Early designs
z Micromotion introduced first practical Coriolis Mass Flow Sensor 1977
z Single curved tube
z Vibration measured with respect to case
z “Case Referenced”
z Suffered from strong internal and external vibrations
z Required rigorous mounting
z Concrete blocks
VersaFlow Coriolis Flow Meter
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Moving on …
z Manufacturers began to use twin tube systems

z Oscillation of two tubes in counter-phase
z Dampens vibrations of each tube
z Helps minimise pressure on housing and process connections
z Stable zero point
z Flow splitting device required
z Prone to clogging
z Introduces additional pressure drop
z Relatively poor cleaning
z Improved bent single tube design
z Floating reference
z Double loops
VersaFlow Coriolis Flow Meter
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Single straight tube still the goal … until 1994
z Krohne introduced WORLD’S first single straight tube Coriolis flowmeter
z G Series
z Single straight measuring tube: Titanium
z Still had installation concerns
z Did require clamping in specific manner
z Did however introduce SST into market
z Performance met customer demands
z Solved previous difficult application problems
z High viscosity
z Cleaning-in-place
z Solids handling and abrasive media
VersaFlow Coriolis Flow Meter