Flowmeters is the instrument used for measuring flow in equipment.

Flowmeters are the instruments used in chemical or any industry to measure flow, it is important from the point of view of operation, efficiency, safety.

1. Flow Meter
Index
•What is flow meter
•What are the different types of
flowmeters
•Working principle of each type of flow
meter
•Detailed specifications of flow meters
•Sizing and selection of flow meters
•Advantages & disadvantages of flow
meters
•Applications of flow meters
By: Abdul Saleem
1

2. Flow Meter
•A flow meter is a device used to measure the volume or mass of a gas or liquid.
•Aflow meter(or flow sensor) is an instrument used to measure linear,
nonlinear, mass or volumetric flow rate of a liquid or a gas.
By: Abdul Saleem
2

3. Flow Meter
•Variable Area Flow meter
•Differential Pressure Flow meter
•Coriolis Flow meter
•VotexFlow meter
•Ultrasonic Flow meter
•Electromagnetic Flow meter
•Thermal Mass Flow meter
•Turbine Flow meter
Types of flow meters
By: Abdul Saleem
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4. Flow Meter
In this type there will be variable orifice and
pressure drop is relatively constant
Types
•Rotameter
•Piston type
Variable Area Flow meter
By: Abdul Saleem
4

5. Flow Meter
It includes a vertical tube through which the fluid
flows whose diameter increases from the bottom to
the top and a float which can move vertically in the
tube. As the flow increases this float moves to a
higher position until its resistance to the fluid flow is
balanced by the float’s buoyed weight in the fluid, a
value which is constant and independent of the
flowrate. The position of the float is a measure of the
flowrate. The flowrate values can be read on a scale.
Variable Area Flow meter
Rotameter
By: Abdul Saleem
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6. Flow Meter
P&ID Symbol of representation
Variable Area Flow meter
Rotameter
Sizing formula
Q = Volumetric Flow Rate
Vf= Float Volume
K = Taper Constant
Af= Float Area
A = Fluid Passing Area
Df = Float Density
g = Acceleration due to gravity
D = Fluid Density
??????=????????????2g??????
?
/??????
?
??????
?
??????−1
??????=????????????2g??????
?
/??????
?
??????
?
??????−1
By: Abdul Saleem
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7. Flow Meter
Variable Area Flow meter
Rotameter
Specifications
•Turndown ratio is 10:1.
•Accuracy: ±2% of FSD
•Repeatability: ±1 ?4% FSD
•Available Brands: Brooks, ABB,
•Available Range: 5 ~200 gpm
By: Abdul Saleem
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8. Flow Meter
Advantages
•Linear Scale, long measurement rang, low pressure drop
•Simple to install & maintain
•It can be designed to cover a wide range of pressures and temperatures.
•The rotameter can easily be sized or converted from one kind of service to another.
•It is an exceptionally practical flow measurement device.
•The pressure drop across the float is low and remains essentially constant as the flowrate changes.
Float responseto flowrate changes is linear,
•Turndown ratio is 10:1.
•Commonly used to provide cost-effective local indication of small liquid or gas flows
•Rotameters are repeatable up to ±1 ?4% of the instantaneous flowrate
Variable Area Flow meter
Rotameter
By: Abdul Saleem
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9. Flow Meter
Disadvantages
•Low accuracy –uncertainty on volumetric flowrate is ~2% of reading
•Generally small turndown
•Tendency of float to ‘stick’ at low flows
•Requirement for buoyancy correction in liquids
•Not applicable for opaque, dirty fluids
•Shall be installed in vertical direction and fluid shall flow from bottom to top
•Thefloatcan get stuck when flow turns on suddenly
•Not recommended in hazardous areas
•More Sensitive to viscous fluids
Variable Area Flow meter
Rotameter
By: Abdul Saleem
9

10. Flow Meter
Applications
•Applicable for Clean Liquids and gasses
Variable Area Flow meter
Rotameter
By: Abdul Saleem
10

11. Flow Meter
Variable Area Flow meter
Positive Displacement / Piston type
It consist of cylinder or piston fitted to it , as the fluid
flows through meter displacement is created count of
number of displacements is proportional to flow rate
By: Abdul Saleem
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12. Flow Meter
Parts
1. Body
2. Piston or Gear wheel or Displacement disk
3. Counter
Variable Area Flow meter
Positive Displacement / Piston type
Applications
•Fuel Oil Service
•Thar service
•Viscous service
•Dirty fluids
By: Abdul Saleem
12

13. Flow Meter
Specifications:
•Available sizes: ½” to 3”
•Operating pressure: 7 to 10 barg, and 103 bargfor industrial purpose
•Max pressure drop: 2.5bar
•Measurable ranges: 1 to 100 gpm
•Accuracy: ±5% for viscous liquids, ±2% for non-viscous liquids
•Viscosity limit: 200 ~ 10000 cP
Variable Area Flow meter
Positive Displacement / Piston type
By: Abdul Saleem
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14. Flow Meter
Advantages:
•Inexpensive
•Wide range of applications
•Very basic operations
•Easy installation
Variable Area Flow meter
Positive Displacement / Piston type
By: Abdul Saleem
14

15. Flow Meter
Disadvantages:
•Limited Accuracy
•Subject to density viscosity and temperature
•Not applicable for fluids with abrasives
•More chances if erosion
•Minimum viscosity shall be >200 cP
Variable Area Flow meter
Positive Displacement / Piston type
By: Abdul Saleem
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16. Flow Meter
Differential pressure meterswork on the principle of
partially obstructing the flow in a pipe. This creates
a difference in the static pressure between the
upstream and downstream side of the device. This
difference in the static pressure (referred to as the
differential pressure) is measured and used to
determine the flow rate.
Differential Pressure Flow meter
By: Abdul Saleem
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17. Flow Meter
Types:
1.Orifice Flow Meter
2.Venturi Meter
3.Flow Nozzle
4.Pitot tube
5.V -cone
Differential Pressure Flow meter
By: Abdul Saleem
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18. Flow Meter
Working Principle:
This type of flow meter consists of a plate with
an aperture on it, which reduces the flow area
result of which there will be pressure drop.
Square root of this pressure drop is
proportional to the flow rate.
Differential Pressure Flow meter
Orifice
By: Abdul Saleem
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19. Flow Meter
Types of Orifice plates
•Concentric Orifice
•Eccentric Orifice
•Segmented Orifice
•Quadrant Edge orifice
Differential Pressure Flow meter
Orifice
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19

20. Flow Meter
Parts Of Orifice
Differential Pressure Flow meter
Orifice
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21. Flow Meter
Specifications
Differential Pressure Flow meter
Orifice
•Turndown 4:1
•Beta ratio: 3~7
•Accuracy: ±2% ~ ±4% of full scale
•Pressure drop: Medium (40 to 90%)
•Upstream Down Stream: 10D:5D
•Operating temperature: up to 800
o
C
•Operating pressure: up to 400 bar
•Uncertainty: 0.6 ~ 0.75
By: Abdul Saleem
21

22. Flow Meter
Sizing of Orifice as per ISO-5167-2
Differential Pressure Flow meter
Orifice
Where
•β= ratio of Orifice ID to Pipe ID = ??????/??????(units:m)
•q
v
= Volumetric Flow rate (units:m
3
/s)
•q
m
= Mass Flow rate (units:kg/s)
•C = discharge coefficient ≈ 0.61 for Re > 30,000
(Ref-ISO5167 Anex-A)
•ρ= Density (units:kg/m
3
)
•ΔP = down stream pressure -upstream pressure (P1-P2) (units:Pa)
(or)
By: Abdul Saleem
22

23. Flow Meter
Differential Pressure Flow meter
Orifice
Advantages
•The Orifice meter is very cheap as compared to other types of
flow meters.
•Less space is required to Install and hence ideal for space
constrained applications
•Operational response can be designed with perfection.
•Installation direction possibilities: Vertical / Horizontal / Inclined.
By: Abdul Saleem
23

24. Flow Meter
Differential Pressure Flow meter
Orifice
Disadvantages
•Easily gets clogged due to impurities in gas or in unclear liquids
•The minimum pressure that can be achieved for reading the flow is sometimes difficult to achieve
due to limitations in the vena-contractalength for an Orifice Plate.
•Downstream pressure cannot be recovered in Orifice Meters. Overall head loss is around 40% to
90% of the differential pressure .
•Flow straighteners are required at the inlet and the outlet to attain streamline flow thereby
increasing the cost and space for installation.
•Orifice Plate can get easily corroded with time thereby entails an error.
•Discharge Co-efficient obtained is low.
•Measurement will be effected by viscosity
By: Abdul Saleem
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25. Flow Meter
Differential Pressure Flow meter
Orifice
Applications
•Natural Gas
•Water Treatment Plants
•Oil Filtration Plants
•Petrochemicals and Refineries
By: Abdul Saleem
25

26. Flow Meter
Device used to measure the flow rate of fluid
flowing through it.
It consist of a section of pipe with short
straight conical entrance and a long straight
conical outlet with a straight lean throat in
between
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
26

27. Flow Meter
Constructional details
Differential Pressure Flow meter
Venturi
P&ID Symbol
By: Abdul Saleem
27

28. Flow Meter
Working Principle
•Venturi meter is work on Bernoulli’s equation and its simple principle is when velocity increases
pressure decreases.
•Cross sectional area of throat section is smaller than inlet section due to this the velocity of flow at
throat section is higher than velocity at inlet section, this happen according to continuity equation.
•The increases in velocity at the throat result in decreases in pressure at this section , due to this
pressure difference is developed between inlet valve and throat of the venturi meter.
•This difference in pressure is measured by manometer by placing thisbetween the inlet section
and throat.
•Using pressure difference value we can easily calculate flow rate through the pipe.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
28

29. Flow Meter
Working Principle
•Venturi meter is work on Bernoulli’s equation and its simple principle is when velocity increases
pressure decreases.
•Cross sectional area of throat section is smaller than inlet section due to this the velocity of flow at
throat section is higher than velocity at inlet section, this happen according to continuity equation.
•The increases in velocity at the throat result in decreases in pressure at this section , due to this
pressure difference is developed between inlet valve and throat of the venturi meter.
•This difference in pressure is measured by manometer by placing thisbetween the inlet section
and throat.
•Using pressure difference value we can easily calculate flow rate through the pipe.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
29

30. Flow Meter
Specifications
•Pressure recovery better than orifice.
•Turndown ratio: 4 : 1.
•In venturi tubes, pressure loss is low and viscosity effect is high.
•Accuracy: 1% of full scale
•Uncertainty: 0.925 ~ 0.985
•Essential upstream pipe length of a venturi tube is 5 to 20 diameters
•Venturi tubes exist in sizes up to 72″.
•A venturi tube can pass 25 to 50% extra flow than that of an orifice plate keeping the same drop
in pressure.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
30

31. Flow Meter
Specifications Cont..
•Since, cost of a venturi tube is high, its mainly engaged on larger flows & in more complicated or
challenging flow applications.
•Almost insensitive to velocity profile effects and consequently call for less straight pipe run
•Resistant to corrosion, erosion, and internal scale build up, owing to their contoured nature,
pooled with the self-scouring action of the flow through the tube.
•Use of venturi tubes involves a lot of savings in installation and operating and maintenance costs.
•Applicable in profiles with Turndown Rates or lower pressure drops, particularly in areas where
orifice plates fails to perform.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
31

32. Flow Meter
Calculation as per ISO 5167-3
Where
qm= Mass Flow Rate
C= Coefficient of Discharge
d= Throat Diameter
ΔP= Inlet Pressure P1 –Throat Pressure P2
ρ= Density
ξ= Expansion Factor
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
32

33. Flow Meter
Advantages
•Moderately low pressure loss (≈10% of ΔP)
•Less susceptible to damage / wear
•Suitable for wet gas flow
•Less chances of getting clogged with sediment
•Discharge coefficient is high
•Can be installed vertically, horizontally or inclined.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
33

34. Flow Meter
Disadvantages
•Large physical size
•Greater cost of manufacture
•More susceptible to “tapping errors” in high
Reynolds number gas flows owing the high velocity
fluid passing the pressure tapping at the throat.
•Cannot be altered.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
34

35. Flow Meter
Applications
•Used where high pressure recovery is required
•Measure high flow rate in pipes having diameter in a few meters
•Applicable for Water, Gases, Suspended solids, Clean, dirty and viscous liquid and few slurry
services as well.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
35

36. Flow Meter
Applications
•Used where high pressure recovery is required
•Measure high flow rate in pipes having diameter in a few meters
•Applicable for Water, Gases, Suspended solids, Clean, dirty and viscous liquid and few slurry
services as well.
Differential Pressure Flow meter
Venturi
By: Abdul Saleem
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37. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Working Principle:
This Principle involves a dynamic pressure
measurement and static pressure measurement
The difference of dynamic and static pressure is
proportional to flow rate of the fluid.
By: Abdul Saleem
37

38. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Construction:
•Consists of a rod shaped Pipe inserted perpendicularly in the process piping with several holes in
the front and rear of the pipe
•These holes are connected to differential pressure transmitter
•Wake Frequency calculation is required to pass while sizing inorderto avoid hazards
By: Abdul Saleem
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39. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Calculation
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40. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Calculation
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41. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Calculation
K = K-factor
Cw= Resistance value
Re = Reynolds number
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42. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Specifications
•Accuracy: ±0.5 ~ ±5 of FSR
•Turndown ratio: 3:1
•Upstream and down stream pipe lengths: 20D:30D
•Pressure Loss:
•Viscosity effect: low
•K factor: 0.57~2.23
P&ID Symbol
By: Abdul Saleem
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43. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Advantages
•It can be inserted into existing and pressurized pipelines (called hot-tapping) without requiring a
shutdown.
•Presents little resistance to flow.
•Inexpensive to buy.
•Simple types can be used on different diameter pipes.
By: Abdul Saleem
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44. Flow Meter
Differential Pressure Flow meter
Pitot Tube
Disadvantages
•pitot tube detects the flow velocity at only one point in the flowstream
•Turndown is limited to approximately 4:1 by the square root relationship between pressure and
velocity.
•If steam is wet, the bottom holes can become effectively blocked. To counter this, some models
can be installed horizontally.
•Sensitive to changes in turbulence and needs careful installation and maintenance.
•The low pressure drop measured by the unit, increases uncertainty, especially on steam.
•Placement inside the pipework is critical.
By: Abdul Saleem
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45. Flow Meter
Differential Pressure Flow meter
Pitot Tube
•Applications
•Clean Liquids
•Occasional use to provide an indication of flow rate
•Determining the range over which a more appropriate steam flow meter may be used.
By: Abdul Saleem
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46. Flow Meter
Differential Pressure Flow meter
Vortex
Working Principle:
Vortex flow meters operate under the vortex shedding
principle, where an oscillating vortexes occur when a fluid
such as water flow past a bluff (as opposed to
streamlined) body. The frequency that the vortexes are
shed depend on the size and shape of the body. It is ideal
for applications where low maintenance costs are
important. Industrial size vortex meters are custom built
and require appropriate sizing for specific applications.
By: Abdul Saleem
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47. Flow Meter
Differential Pressure Flow meter
Vortex
By: Abdul Saleem
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48. Flow Meter
Differential Pressure Flow meter
Vortex
Construction:
By: Abdul Saleem
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49. Flow Meter
Differential Pressure Flow meter
Vortex
Specifications:
•Linear output signal
•Accuracy: ±0.75% to ±1.0% of FSR
•Repeatability: better than ±0.15% of rate
•Rangeability: 10:1
•AvailabelPipe sizes: ½” to 12”
•Viscosity effect: Medium
Specifications:
•Minimum Flow at Re:10000 ~ 10500
•Upstream and Downstream run: 20D:5D
•Minimum Velocity: 0.6m/s
By: Abdul Saleem
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50. Flow Meter
Differential Pressure Flow meter
Vortex
Calculation: (ISO/TR 12764) Where
St -
Strouhal number
f -
vortex shedding frequency
d -
width of the bluff body
V -
average fluid velocity
A -Area of pipe ID
B –Blockage factor
By: Abdul Saleem
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51. Flow Meter
Differential Pressure Flow meter
Vortex
P&ID Symbol
By: Abdul Saleem
51

52. Flow Meter
Differential Pressure Flow meter
Vortex
Advantages:
•Vortex meters can be used for liquids,
gases and steam
•Low wear (relative to turbine flow meters)
•Relatively low cost of installation and
maintenance
•Low sensitivity to variations in process
conditions
•Stable long term accuracy and
repeatability
Advantages:
•Relatively low pressure drop (≈0)
•Applicable to a wide range of process
temperatures
•Available for a wide variety of pipe sizes
By: Abdul Saleem
52

53. Flow Meter
Differential Pressure Flow meter
Vortex
Disadvantages:
•Not suitable for very low flow rates
•Minimum length of straight pipe is required upstream and downstream of the vortex meter
•change in sheddarbar geometry owning to erosion
•change in sheddarbar geometry owning to deposits, i.e. Wax
•corrosion of upstream piping
•change in position of sheddarbar if not properly secured
•Hydraulic noise.
•Not applicable for 2 way flow.
By: Abdul Saleem
53

54. Flow Meter
Differential Pressure Flow meter
Vortex
Applications:
•Vortex flow meters are suitable for a variety of applications and industries but work best
with clean, low-viscosity, medium to high speed fluids.
Some of the main uses include:
•Custody transfer of natural gas metering
•Steam measurement
•Flow of liquid suspensions
•General water applications
•Liquid chemicals & pharmaceuticals
By: Abdul Saleem
54

55. Flow Meter
Turbine
Turbine flow meters measure the velocity of liquids, gases
and vapors in pipes, such as hydrocarbons, chemicals,
water, cryogenic liquids, air, and industrial gases.
Turbine flow meter consists of turbine blades, spool piece,
pickup sensor, transmitter.
By: Abdul Saleem
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56. Flow Meter
Turbine
Working Principle:
Turbine flow meter consists of bladed rotor which
rotates with the mechanical energy of the fluid.
These rotations are proportional to flow rate of
the fluid.
Number of rotations can be counted by magnetic
pickup and flow rate can be calculated
By: Abdul Saleem
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57. Flow Meter
Turbine
Parts:
By: Abdul Saleem
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58. Flow Meter
Turbine
Specifications:
•TurnDownRatio: 10:1 ~ 100:1
•Accuracy: ±0.25
•Upstream Down Stream: 5D:10D
•Pressure Loss
•Viscosity effect
Calculations:
Q = (Tk X f)/k
Q = Volumetric Flow Rate
f = Frequency of the pulses
k = k-factor (eg: pulses per litre)
Tk = Time Constant
P&ID Symbol
By: Abdul Saleem
58

59. Flow Meter
Turbine
Advantages:
•No external power supply for Rotating vane and Woltmanmeters
•Turbine flowmeters are suitable for cryogenic liquids
•Turbine flowmeters usable at extreme temperatures and pressures
•Low pressure drop across the flow meter
•Most effective in applications with steady, high-speed flows
By: Abdul Saleem
59

60. Flow Meter
Turbine
Disadvantages:
•should not be operated at high velocity because premature bearing wear and damage
can occur.
•Not reliable for steam
•They do cause some pressure drop where that may be a factor such as gravity flows.
•Less accurate to low flow rates
•Not suitable for high viscous fluids
•Not effective with swirling fluids
•Suitable only for clean liquids and gases
•Not Suitable in Vibration lines & high viscous liquids
By: Abdul Saleem
60

61. Flow Meter
Turbine
Applications:
•Suitable clean Liquids & Gases
•Suitable for less viscous fluids
•Water and waste water
•Gas utility
•Chemical
•Power, food and beverage
•Aerospace, pharmaceutical
•Metals and mining, and pulp and paper
By: Abdul Saleem
61

62. Flow Meter
Electromagnetic
Principle
Magnetic flow meters works based on Faraday’s Law of
Electromagnetic Induction. According to this principle,
when a conductive medium passes through a magnetic
field B, a voltage E is generated which is proportional to the
velocity v of the medium, the density of the magnetic field
and the length of the conductor.
By: Abdul Saleem
62

63. Flow Meter
Magnetic
Calculation: (ISO 6817)
E = (k * B * D * V)
where,
E = Induced Voltage (Linear with velocity)
k = Proportionality Constant
B = Magnetic Field Strength (Coil Inductance)
D = Distance between electrodes
V = Velocity of process fluids
By: Abdul Saleem
63

64. Flow Meter
Magnetic
Parts
By: Abdul Saleem
64

65. Flow Meter
Magnetic
Specifications
•Minimum Conductivity: 5 to 20 µσ/cm
•Turndown ratio: 40:1
•Accuracy: ±0.5% fo FSR
•Upstream Down stream: 5D
•Repeatability : 0.2%
•Pressure Losdd: None
•Available line sizes: 1/10 ~ 100 In
Specifications Cont..
•2" to 48" in size with a flow rate of 0.05 to 10
m/sec
P&ID Symbol
By: Abdul Saleem
65

66. Flow Meter
Magnetic
Advantages
•Zero obstruction to the flow hence can measure wide range of flow with heavy suspended
impurities, including mud, sewage and wood pulp.
•No pressure head loss other than that of the length of straight pipe lengths.
•They are not very much affected by upstream flow disturbances.
•They are practically unaffected by variation in density, viscosity, pressure and temperature.
•Electric power requirements can be low (15 or 20 W), particularly with pulsed DC types.
•These meters can be used as bidirectional meters.
•The meters are suitable for acids, bases, water and aqueous solutions because the lining
materials selected are not only good electrical insulators but also are corrosion resistant.
•The meters are widely used for slurry services because no obstruction & liners such as
polyurethane, neoprene and rubber have good abrasion or erosion resistance.
•They are capable of handling extremely low flows.
By: Abdul Saleem
66

67. Flow Meter
Magnetic
Disadvantages
•These meters can be used only for fluids which have reasonable electrical conductivity.
•Accuracy is only in the range of ±1% over a flow rate range of 5%.
•The size and cost of the field coils and circuitry do not increase in proportion to their size of pipe
bore. Consequently small size meters are bulky and expensive.
By: Abdul Saleem
67

68. Flow Meter
Magnetic
Applications
•Used for any fluid which is having an electrical conductivity between 5~20 µσ/cm.
•Fluids like sand water slurry, coal powder, slurry, sewage, wood pulp, chemicals, water other than
distilled water in large pipe lines, hot fluids, high viscous fluids specially in food processing
industries, cryogenic fluids can be metered by the electromagnetic flow meter.
By: Abdul Saleem
68

69. Flow Meter
Ultrasonic
Principle
•Ultrasonic flowmeters use sound waves
to determine the velocity of a fluid
flowing in a pipe
•The basic principle of operation employs
the frequency shift (Doppler Effect) of an
ultrasonic signal
•At no flow frequency of transmitted sound
wave is equal to frequency of sound reflected
back
•At Flow condition transmitted frequency and
received frequency will be different, as the
flow increases frequency of sound wave also
increases which is linear.
By: Abdul Saleem
69

70. Flow Meter
Ultrasonic
Types
•Transit time
•Doppler shift
•Open Chanel
•Intrusive type
•Non Intrusive type
P&ID Symbol
By: Abdul Saleem
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71. Flow Meter
Ultrasonic
Calculation (ISO17089) P&ID Symbol
By: Abdul Saleem
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72. Flow Meter
Ultrasonic
Specifications
•Limited to flow velocities up to 120m/s
•Accuracy: ±1% ~ ±5% of FSR
•Repeatability: 0.2(Doppler), 0.5(Transit Time)
•Turndown ratio: 10:1(Doppler), 20:1(Transit Time)
•Up-stream & Down-stream: 5D : 30D
•Pressure drop: Very less
By: Abdul Saleem
72

73. Flow Meter
Ultrasonic
Advantages:
•Ultrasonic meters are made up of no moving parts.
•They experience no pressure loss.
•They endow with maintenance-free operation. It is a key advantage as compared to conventional
mechanical meters such as positive displacement meters, turbines etc.
•Furthermore, Ultrasonic flow meters are consistently more accurate and reliable than a lot of
other metering systems.
•With the emergence of 3-beam ultrasonic, all other flow meters like mass, vortex, positive
displacement and turbine flow meters which are used to measure non-conductive fluids, have
been successfully replaced by ultrasonic meters.
By: Abdul Saleem
73

74. Flow Meter
Ultrasonic
Disadvantages:
•Still problematic for liquid and gas measurements
•Sound beam must traverse a representative cross section, therefore flow profile dependent. Long
inlet and outlet sections required
•Errors due to deposits
•Transit time meters require clean liquids
•Doppler meters only for slight contamination or few gas bubbles
•Doppler meters affected by sound velocity changes due to temperature, density and
concentration
•Unsuitable for heavily contaminated liquids
•Gas bubbles cause errors
By: Abdul Saleem
74

75. Flow Meter
Ultrasonic
Applications
•Ultrasonic flow meters are perfect for wastewater applications or any other dirty liquid which is
conductive or water based.
•Ultrasonic flow meters normally does not work with distilled water or drinking water. Aerations
would be needed in the clean liquid applications.
•Ultrasonic flow meters are also best suited for applications where low pressure drop, chemical
compatibility, and low maintenance are involved.
By: Abdul Saleem
75

76. Flow Meter
Coriolis
Principle
A Coriolis flow meter contains a tube which is
energized by a fixed vibration. When a fluid (gas
or liquid) passes through this tube the mass flow
momentum will cause a change in the tube
vibration, the tube will twist resulting in a phase
shift. This phase shift can be measured and a
linear output derived proportional to flow.
By: Abdul Saleem
76

77. Flow Meter
Coriolis
Calculation
Fc= 2*m*w*V
m= mass (kg)
w= angular velocity (rad/s)
V= velocity (m/s) P&ID Symbol
Specifications
•Accuracy: ±0.4% of FSR
•Turndown ratio: 100:1 ~ 200:1
•minimum gas density req.: 4.5 kg/m3
(Changes from vendor to vendor)
•No Temp / Pressure / Viscosity
•Upstream & Down Stream : 0D:0D
•Uncertainity: ±0.9 to ±0.2%
By: Abdul Saleem
77

78. Flow Meter
Coriolis
Advantages
•True mass flow measurement
•Additional temperature and density measurements
•Very high accuracy for mass flow measurements
•Highly accurate density measurement
•Unaffected by pressure, temperature and viscosity
•No inlet and outlet sections required
•Operates in both flow directions (forward and reverse)
•Measuring range settings can be optimized for flow rate and density
•Self-draining
By: Abdul Saleem
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79. Flow Meter
Coriolis
Disadvantages
•Affected by gas inclusions
•Vibration sensitive when improperly installed
•Limited choice of materials
•Nominal diameter limited at the top
Applications
•Pulp and paper processing
•Petroleum and oil
•Chemical processing
•Wastewater handling
By: Abdul Saleem
79

80. Flow Meter
Thermal Mass
Principle
Thermal mass flow metersemploy the thermal
dispersion principle whereby the rate of heat
absorbed by a fluid flowing in a pipe or duct is
directly proportional to its mass flow. In a typical
thermal flow meter gas flowing over a source of
heat absorbs the heat and cools the source.
As flow increases, more heat is absorbed by the
gas. The amount of heat dissipated from the heat
source is proportional to the gas mass flow and
its thermal properties. Therefore, measurement
of theheat transfersupplies data from which a
mass flow rate may be calculated.
By: Abdul Saleem
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81. Flow Meter
Thermal Mass
Specifications
•High Turndown ratio 10:1 to 50:1.
•Measuresaccurately at low velocities (<25ft/min)
•Measurement error : 1~2% of FSR
•Upstreamdownstream15D:5D
Calculation ISO14511
Qm= Kq/(C
p
(T
2
-T
1
))
Qm=mass flow
T1=UpstreamTemperature
T2 = Downstream Temperature
(T2 -T1) = temperature difference
K = meter coefficient
q=electric heat rate
Cp= specific heat of the fluid
By: Abdul Saleem
81

82. Flow Meter
Thermal Mass
Advantages
•Measure gas mass flow rate directly
•Suitable for applications where temperature and pressures fluctuate
•Highly accurate and repeatable measurements with a typical accuracy of ±1% FS
•Able to measure accurately low gas flow rates or low gas velocities
•Excellent turn down ratio, typically 50:1
•No moving parts
Disadvantages
•Gas mass meter use is limited to clean, non abrasive fluids
•Presence of moisture or droplets can lead to measurement inaccuracy
•Thermal properties must be known: variation from calibrated values can cause inaccuracies
•Relatively high initial cost
By: Abdul Saleem
82

83. Flow Meter
Thermal Mass
Applications
•used for the regulation of low gas flows.
•Compressed air flow and distribution
•Natural gas consumption egfor burner and boiler feed control
•Monitoring and control of stack or flue gas (where composition known)
•Landfill gas recovery
•Flare gas measurement
•Gas flow mixing & blending
•Gas leak testing and detection
By: Abdul Saleem
83

84. Flow Meter
P&IDSymbols
By: Abdul Saleem
84

85. Flow Meter
Flow meter selection Chart
By: Abdul Saleem
85

86. Flow Meter
Flow meter selection Chart
By: Abdul Saleem
86

87. Flow Meter
Reference standards
By: Abdul Saleem
https://www.slideshare.net/MaRi0niLo/flow-sensors-55384766
87

88. Flow Meter
Application Chart
By: Abdul Saleem
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