1. Industrial Instrumentation
Dr. –Ing. Naveed Ramzan
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan
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2. Flow Sensors
If a flow meter is installed there will be costs involving the instrument, pipe work modification, secondary instrumentation, supplies, intrinsic safety, maintenance, calliberation checks etc. …………
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

3. Plant control, for product quality and safety reasons.
Reasons for Flow Metering
Plant control, for product quality and safety reasons.
Custody transfer, both interplant and selling to outside customers.
Filling of containers, stock tanks and transporters.
Energy, mass balancing for costing purpose and health monitoring of heat exchangers.
Health monitoring of pipelines and on-line analysis equipment, Government and company legislation may dictate the use here of such equipment.
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

4. Differential Pressure Meters. Rotary Meters.
Types of Flow Meters
Differential Pressure Meters.
Rotary Meters.
Displacement
Inferential
New Flow Meters.
Electromagnetic
Vortex Shedding
Ultrasonic
Cross Correlation
Tracer
Swirl
Fluidic
Point Velocity Meters.
Mass Flow Maters.
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

5. Orifice Plate Dall Tube Venturi Tube Pitot Tube Rota meter
Differential Pressure Meters
Orifice Plate
Dall Tube
Venturi Tube
Pitot Tube
Rota meter
Target mater
Averaging Pitot
Nozzle
Spring Loaded
Intake Meter
Elbow Meter
Bypass Meter
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

6. Parts of differential flow meters
Primary element
(Part of meter used to restrict the fluid flow in pipe line to produce differential pressure)
They include
Orifice plate
Venturi tubes
Flow nozzles
Pitot tube etc.

7. Force balance meters etc.
Parts of differential flow meters
Secondary element
(measure the differential pressure produced by primary elements and convert them to usable forces or signals )
Secondary elements;
Manometers
Bellow meters
Force balance meters etc.

8. Obstruction Meters
Orifice Meters
Venturi Meters
Flow Nozzles

9. Flow Through an Orifice Meter

10. Flow Through an Orifice MeterP1 P2 d D P1 P

11. Flow Through an Orifice Meter
Cheapest and Simplest
But biggest pressure drop and power lost (C~ )
Side Note:
Pressure drop caused by friction and turbulence of shear layer downstream of vena contracta
10k Re
0.85
5000
100k
0.6
b=d/D
0.1
0.8

12. Obstruction Meters
Orifice Meters
Venturi Meters
Flow Nozzles

13. Flow through a Venturi Meter
In a venturi, 0.95 < C < 0.98
Advantage:
Pressure recovery
Uses little power

14. Back to the Nozzle P1 P2 P1 P P2

15. Shorter and cheaper than venturi But larger pressure drop.
The Nozzle Flowmeter
Shorter and cheaper than venturi
But larger pressure drop.
Thus, more power lost in operating.
0.98 C
0.86
105
103 Re

16. Obstruction Meters
Orifice Meters
Venturi Meters
Flow Nozzles

17. Total pressure is constant throughout
Flow through a Nozzle
Basic Equations:
a.) Continuity:
mass in = mass out
b.) Bernoulli’s Eqn.
Total pressure is constant throughout

18. Flow through a Nozzle

19. Flow through a Nozzle

20. Flow through a Nozzle DP

21. Flow through a Nozzle Y = Compressibility Factor
=1 for incompressible flow or when DP<< Pabs
C= Discharge Coefficient
=f(Re) and
nature of specific flow meter DP P

22. Elbow Flow meter Rota meter Force balance Drag Force Gravity Buoyancy
Differential Pressure Meters ( Cont‘d)
Force balance
Drag Force
Gravity
Buoyancy
(usually negligible)
Elbow Flow meter
Rota meter
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan
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23. Rotameter, variable-area-flowmeter
Force balance
Drag Force
Gravity
Buoyancy
(usually negligible)
Derived on next slide

24. For a fixed x-position, A is fixed. Then
Rotameter
Equations
For a fixed x-position, A is fixed. Then

25. Pitot Tube

26. Displacement Meters Gear Oval wheel Vane Meter Gear (Roots)
Rotary Meters ( Displacement Meters)
Displacement Meters
Gear
Oval wheel
Vane Meter
Gear (Roots)
Diaphragm Meter
Liquid Sealed Meter
Inferential Meters
Turbine Meter
Hoverflo Meter
-- This family of meters separates the incoming liquid or gas into discrete volumes and is transfering them downstream operates a counting mechanism. They are mainly used where a high order of accuracy is required and stoppage of the flow in an event is not an embarrasment.
--- extensively used for custody transfer of oils and fuels
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan
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27. What are Rotary Meters ( Displacement Meters)
Devices which are used to measure mass or volumetric flow rate of gas or liquid by using a rotating element.
25/03/2017

28. Positive Displacement Rotary Meters Inferential Rotary Meters
Types of Rotary Meters ( Displacement Meters)
Types of Rotary Meters
Positive Displacement Rotary Meters
Inferential Rotary Meters
25/03/2017

29. PD Rotary Meters ( Displacement Meters)
Positive displacement flow meters, also know as PD meters, measure volumes of fluid flowing through by counting repeatedly the filling and discharging of known fixed volumes.
25/03/2017

30. Principle of Operation
PD Rotary Meters ( Displacement Meters)
Principle of Operation
POSITION 1. As the bottom impeller rotates in a counterclockwise direction towards a horizontal position, fluid enters the space between the impeller and cylinder.
POSITION 2. At the horizontal position, a definite volume of fluid is contained in the bottom compartment.
25/03/2017

31. Principle of Operation
PD Rotary Meters ( Displacement Meters)
Principle of Operation
POSITION 3. As the impeller continues to turn, the volume of fluid is discharged out the other side.
POSITION 4. The top impeller, rotating in opposite direction, has closed to its horizontal position confining another known and equal volume of fluid.
25/03/2017

32. Oval Gear Nutating Disk Oscillating Piston Multi Piston
PD Rotary Meters ( Displacement Meters)
Oval Gear
Nutating Disk
Oscillating Piston
Multi Piston
Rotating Impellers
Rotating Valve
Birotor
Roots Meter
Helix Meters
25/03/2017

33. PD Rotary Meters ( Displacement Meters)
Nutating Disk
A nutating disc meter has a round disc mounted on a spindle in a cylindrical chamber.
By tracking the movements of the spindle, the flowmeter determines the number of times the chamber traps and empties fluid.
25/03/2017

34. PD Rotary Meters ( Displacement Meters)
Oval Gear
Two identical oval rotors mesh together by means of slots around the gear perimeter.
The oval shaped gears are used to sweep out an exact volume of the liquid passing through the measurement chamber during each rotation.
25/03/2017

35. The flow rate can be calculated by measuring the rotation speed.
PD Rotary Meters ( Displacement Meters)
Oval Gear
The flow rate can be calculated by measuring the rotation speed.
25/03/2017

36. The roots meter is similar in many respects to the oval gear meter.
PD Rotary Meters ( Displacement Meters)
Roots Meter
The roots meter is similar in many respects to the oval gear meter.
Two-lobed impellers rotate in opposite directions to each other within the body housing.
25/03/2017

37. The flow rate can be calculated by measuring the rotation speed.
PD Rotary Meters ( Displacement Meters)
Roots Meter
These peanut-shaped gears sweep out an exact volume of liquid passing through the measurement chamber during each rotation.
The flow rate can be calculated by measuring the rotation speed.
25/03/2017

38. PD Rotary Meters ( Displacement Meters)
Rotating Impeller
Birotor
25/03/2017

39. Functions without external power
PD Rotary Meters ( Displacement Meters)
Advantages
High accuracy over a wide range of viscosities and flow rates up to 2000 cP with proper clearances.
Extremely good repeatability on high viscosity fluids, very low slippage, long life if little or no abrasive material in the fluid
Low pressure drop
Functions without external power
25/03/2017

40. Rotary Meters ( Displacement Meters)
-- This family of meters separates the incoming liquid or gas into discrete volumes and is transfering them downstream operates a counting mechanism. They are mainly used where a high order of accuracy is required and stoppage of the flow in an event is not an embarrasment.
--- extensively used for custody transfer of oils and fuels
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan
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41. Special construction available for high viscosities and temperatures
PD Rotary Meters ( Displacement Meters)
Advantages
Special construction available for high viscosities and temperatures
Can register near zero flow rate
Measures directly, not an inferential device, for more consistent results
Easy to repair and economical.
25/03/2017

42. Increased maintenance compared to other meters, more moving parts
PD Rotary Meters ( Displacement Meters)
Disadvantages
Increased maintenance compared to other meters, more moving parts
May become damaged by flow surges and gas slugs
Chance of corrosion and erosion from abrasive materials
Derated flow rate capacity for high viscosities and temperatures
Relatively high cost for large sizes
25/03/2017

43. Inferential Meters
The inferential type meters are so-called because rather than measuring the actual volume of fluid passing through them, they “infer” the volume by measuring some other aspect of the fluid flow and calculating the volume based on the measurements
25/03/2017

44. Inferential Meters
The inferential type meters are so-called because rather than measuring the actual volume of fluid passing through them, they “infer” the volume by measuring some other aspect of the fluid flow and calculating the volume based on the measurements
Turbine Meters
Paddle Wheel
Insertion Type
25/03/2017

45. Turbine Flow Meters
A turbine with blades filling the meter can rotate freely on bearings. As the fluid passes it spins the blades round and a magnetic sensor in the body transmits pulses to pulse counting circuits.
It is easily dismantled and if calibrated is very accurate
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

46. Turbine Flow Meters
It consists of a multi-bladed rotor mounted at right angles to the flow and suspended in the fluid stream on a free-running bearing.
The diameter of the rotor is very slightly less than the inside diameter of the metering chamber, and its speed of rotation is proportional to the volumetric flow rate.
25/03/2017

47. Turbine Flow Meters
The rotational speed is a direct function of flow rate and can be sensed by magnetic pick-up, photoelectric cell, or gears. Electrical pulses can be counted and totalized.
25/03/2017

48. Paddle Wheel Meters
Paddle Wheel
25/03/2017

49. Very good repeatability Reduced susceptibility to fouling and deposits
Inferential Meters
Advantages
Very good repeatability
Reduced susceptibility to fouling and deposits
Less sensitive to viscosity changes
Available in large sizes, good value for high flow rates
Low maintenance
Registers near zero flow rate
Disadvantages
High pressure drop that increases drastically with viscosity
Relatively high cost
Indirect measurement
25/03/2017

50. Ultrasonic Flow Meters
New Flow Meters
Electromagnetic
EM Meter
Vortex Shedding Meter
Vortex Generation Meter
Ultrasonic Flow Meters
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

51. New Flow Meters (Cont‘d)
Magnetic Flowmeter
Based upon Faraday’s Law
The fluid is the conductor, must be electrically conductive.
E=BDVx10-8
E=voltage, volts
B=magnetic flux density, gauss
D= length of the conductor, cm
V=velocity of the conductor, cm/sec
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

52. New Flow Meters (Cont‘d)
Swirl Meter
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

53. Coriolis Mass Flowmeter
In the Coriolis meter the fluid is passed through a tube. The tubes are available in different design like tubes of U-shape or horseshoe-shaped. The tubes can either be curved or straight. When two tubes are used the flow is divided when entering the meter and then recombined. The flow when enters the tube encounters oscillating excitation force that causes the tubes to vibrate at a fixed frequency. The vibration is induced in the direction that is perpendicular to flow of fluid. This creates the rotation frame of reference. Consider the tube during oscillation moving up and downward, when the tube is moving upward the fluid flowing in it tends to resist this and forces it downward. When the tube moves in the opposite direction, so does the fluid and a twist in introduced in the tube. All this might not be visible by directly observing. The twist at inlet of fluid and outlet of fluid results in phase difference or time lag and that is dependent on the fluid mass passing through the tube.
PEC – UET Lahore Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan

54. Discussion & Questions?
Dr. Shahid Naveed März 2017 / Dr. –Ing Naveed Ramzan