1. NIDHIN MANOHAR The Boss of Control Loop, Final Control Element

2. CONTROL VALVE AN OVERVIEW

3. TODAY’S DISCUSSION CONTENT - CONTENT - WHAT IS A CONTROL VALVE ?
CONTROL VALVE ACTUATOR & ACCESSORIES
STANDARDS APPLICABLE FOR CONTROL VALVE
FLASHING
CAVITATION
CONTROL VALVE SELECTION & INTERCHANGEABILITY
VALVE GLAND PACKING & MATERIAL OF CONSTRUCTION
CONTROL VALVE LEAKAGE CLASS
CONTROL VALVE CHARACTERISTICS
ARDUOUS SERVICE VALVE
NOISE REDUCTIONS PRACTICES
CONTENT -
WHAT IS A CONTROL VALVE ?
CONTROL VALVE ACTUATOR
STANDARDS APPLICABLE FOR CONTROL VALVE
FLASHING
CAVITATION
CONTROL VALVE SELECTION & INTERCHANGEABILITY
VALVE GLAND PACKING & MATERIAL OF CONSTRUCTION
CONTROL VALVE LEAKAGE CLASS
CONTROL VALVE CHARACTERISTICS
ARDUOUS SERVICE VALVE
NOISE REDUCTIONS PRACTICES

4. WHAT IS A CONTROL VALVE ? CONTROL VALVE
This is a device used to modulate flow of process fluid in line by creating a variable pressure drop in the line .
Normally the pressure drop is made with respect to the control signal received towards flow condition correction required.

5. WHAT IS VALVE FLOW COEFFICIENT ?
VALVE Cv - No. Of US gallon [ USG = 3.7 Ltrs] of water per minute passing through the valve in full open condition with 1 PSI pressure Drop across the valve at 15 deg C temp.
So essentially valve Cv is capacity of valve in terms of water which helps us to identify suitable size required for any fluid in any pressure / temp. condition.
VALVE Kv - Quantity of water in M3/Hr. at temperature between 5 to 40C that will flow through the valve at a specified travel with a pressure drop of 1 Bar.
Kv = 0.856Cv

6. TYPE OF CONTROL VALVE
All Control valve can be divided in two category.
1. Sliding stem ( Globe valve) Rotary shaft ( Quarter turn )
Also valves may be further subdivided as shown below
BY SHAPE BY INTERNAL BY CHAR. BY GUIDING
GLOBE PLUG EQ% TOP
SINGLE SEAT
DOUBLE SEAT
BUTTERFLY CAGE LINEAR CAGE
ANGLE FULL BALL QUICK OPEN TOP & BOTTOM
SLANT SLEEVED PARABOLIC BUSH/BEARING
Y TYPE V BALL

7. VALVE ACTUATOR
Actuator - Mechanism which operates the valve by receiving the control signal.
Type of Actuator
Pneumatic - Spring Diaphragm
Piston Cylinder
Electrical - Not discussed
Hydraulic- Not discussed

8. VALVE ACTUATOR

9. VALVE ACTUATOR

10. VALVE ACCESSORIES VALVE POSITIONERS PNEUMATIC ELECTRONEUMATIC
SMART DIGITAL
PROXIMITY SWITCHES
INDUCTIVE TYPE
PNEUMATIC CAM OPERATED
SOLENOID VALVES
LATCHING/ NON-LATCHING
WITH MANUAL OVERRIDE
SIGNAL BOOSTERS
PRESSURE
VOLUME
SIGNAL INVERTERS
HANDWHEEL
AIR VOLUME TANK

11. CONTROL VALVE STANDARDS
ANSI :- AMERICAN NATIONAL STANDARDS INSTITUTE
B16.34 :- STEEL VALVES
DEFINES CRITERIA FOR VALVE WALL THICKNESS REQUIREMENTS
DEFINES PRESSURE / TEMPERATURE RATINGS
DEFINE HYDRO-TEST REQUIREMENTS
Example :-
A351 CF8M ( Material :- 316SST; Temp range : °F to 1500 °F)
A216 WCB ( Material :- Carbon Steel; Temp range: °F to 1000 °F )
B16.37 :- HYDROSTATIC TEST PROCEDURE
DEFINES REQUIREMENT FOR HYDRO-TEST = 1.5 X MWP
MWP = MAXIMUM WORKING PRESSURE
B :- CONTROL VALVE SEAT LEAKAGE CLASSIFICATION
ESTABLISHES TEST PROCEDURES AND SEAT LEAKAGE CLASSES
API :- AMERICAN PETROLEUM INSTITUTE
SPEC 6B :- DEFINES PIPELINE VALVE
SPEC 600 :- STEEL GAGE VALVES, FLANGED BUTT WELDING ENDS

12. CONTROL VALVE STANDARDS
NACE :- NATIONAL ASSOCIATION OF CORROSION ENGINEERS
NACE MR-01-75
DEFINES SULFIDE STRESS CRACKING RESISTANCE MATERIAL
MATERIAL COMPLY TO NACE STANDARD ARE
CARBON STEEL WITH HEAT TREATMENT
SST 302,304,316,17-4PH
ALLOY STEEL MONEY, HASTELLOY C
MATERIAL NOT SUITABLE FOR NACE ENVIRONMENT IS
CAST IRON

13. CONTROL VALVE STANDARDS
ISA :- INSTRUMENT SOCIETY OF AMERICA
DEFINES STANDARDS FOR CONTROL INDUSTRY
Example :-
VALVE SIZING EQUATIONS.
NOISE PREDICTION TECHNIQUE
CONTROL SIGNAL PSIG, PSIG
OSHA :- OCCUPATIONAL SAFETY AND HEALTH ACT
DEFINES CRITERIA FOR PERMISSIBLE DURATION FOR EXPOSURE OF NOISE LEVEL

14. SHELL REFERENCES Control Valves –Selection , Sizing and Specification
DEP Gen July 1987 &
Basic Process control & Instrumentation Shell M
Shell Best Practice –[Ref Process Measurement and Control Devices –Shell Canada Ltd Standard ]

15. CONTROL VALVE LEAKAGE Control Valve Leakage -
This is basically the fluid which passes through the valve when the valve is fully closed. This value however should not be considered as the valve Cv at NIL Opening.
So this leakage shall depend on the contact of valve plug & seat with the seating force applied for holding the plug over the seat.

16. CONTROL VALVE LEAKAGE

17. VALVE CHARACTERISTICS
Equal % - Rate of change of flow due to change of valve travel is proportional to earlier flow.
Linear - Rate of change of flow is same to rate of change of valve travel
Quick Open - Full capacity attaining without change of travel after initial opening
On/Off - Used mainly as Isolation valves (Pump suction and ESD valves)

18. TRIM AND CAGE DESIGN 1. CHARACTERISING FLOW Linear Cage
Quick Opening Cage
Equal Percentage Cage
Modified Equal percentage flow
2. NOISE ABATEMENT
3. ANTI CAVITATION

19. CHARACTERIZING FLOW BY CAGE TYPE

20. CHARACTERIZING FLOW % Valve Travel 20 40 60 80 100 Design Cv Cv %
Equal %
Linear
% Valve Travel 20 40 60 80
100
Design Cv Cv %
Quick Opening

21. VALVE SELECTION PROCESS FOLLOWED IN RELIANCE
If valve sizing does not give warning of cavitation, flashing or Noise level ( >85dBA) then select standard trim valve.
If valve sizing gives warning of cavitation, flashing or Noise level ( >85dBA) then select arduous service trim valve.
Example:- For cavitation select CAVITROL III stage 1 to 5 valve or CAVITROL 4 valve.
For noise select WHISPER I ,III or WHISPERFLO valve trim.
Select the suitable Approved vendor suiting the product .
Example:- ABB - Introl design or CCI - DRAG design.
In case of very high DP ( DP*100/P1 > 50%) or Noise select ABB or CCI valves.
Example:- Compressor Anti - surge control valves - CCI- DRAG design.

22. VALVE SELECTION PROCESS

23. POPULATION OF CONTROL VALVES AT RELIANCE JAMNAGAR.
Based on above criteria RIL complex has following Installed quantity of valve
Fisher direct supply ( Through Bechtel ) :1800+ valves.
Fisher package supply valves :800+
Masoneilan package supply : 180 +
ABB UK direct supply :150+
CCI USA direct supply :40+
Fisher Gulde package supply : 190 +
Linde Mepag package supply : 120 +
Copes Vulcan package supply : 50 +
Keystone Biffi direct supply : 300 +
Neles Jamesbury direct supply : 630 +
Rotork MOVs direct supply :

24. VALVE INTERCHANGEABILITY
Body pressure rating and certification ( e.g. IBR )
End connection ( Ex:- Screwed or welded flange connection )
Valve Size and type.
Trim Size - Cv
Leakage classification
Body and trim material and certification ( e.g. NACE )
Plug and cage characteristics.
Actuator bench setting / spring range.
Actuator action ( AFC/ AFO )
Process temperature ( For gland packing and body - trim material )

25. Flow Path through a Control Valve - Analogy
Minimum
Geometrical
Flow Area
Vena Contracta
(Minimum Flow Area)
Streamlines Contract as
Flow Approaches Restriction

26. Variation in Pressure and VelocityDP
Pressure
Variation
Velocity
Variation P2
Valve
Inlet
Trim
Exit
Valve
Outlet
Trim
Inlet
Vena
Contracta

27. Pressure Recovery DP Low Recovery High Recovery Valve Inlet Trim Exit
Outlet
Trim
Inlet
Vena
Contracta

28. FLASHING
Flashing :
The formation of vapor bubbles in liquid flow streams at vena contracta.
As liquid passes through a restriction (vena contracta) in a control valve the liquid velocity increases and liquid pressure decreases. And if the pressure at this point falls to or below the vapor pressure of the liquid, vapor bubbles form in the flow stream. Flashing results if this pressure remains below vapor pressure of liquid.
When a liquid flashes into vapor, there is a large increase in volume. Due to increase in volume velocity will increase and hence high velocity will erode the surface.
Flashing damages can be identified by smooth polished appearance of eroded surface. Flashing damages is usually at or near seat line of the valve plug and seat ring.
Vapor pressure :- The pressure at which liquid begins to vaporize.

29. FLASHING DAMAGE ( Tag no. 241FV040 )

30. FLASHING DAMAGE ( Tag no. 241FV040 )

31. CAVITATION
Cavitation : The formation and subsequent collapse of vapor bubbles in liquid flow streams.
As liquid passes through a restriction in a control valve the liquid velocity increases, while the liquid pressure decreases. The pressure reaches a minimum at a point called the vena contracta, and if the pressure at this point falls to or below the vapor pressure of the liquid, vapor bubbles form in the flow stream.
Downstream of the vena contracta, flow area increases, velocity de-creases, and pressure increases.
If this recovered pressure is sufficient to raise the pressure above the liquid vapor pressure, the vapor bubbles will collapse. The collapsing bubbles generate significant noise and vibration, and can mechanically attack pipe walls and valve components.
Cavitation damages can be identified by rough and pitted surface. Cavitation damage may extend to the downstream pipeline if that is where the pressure recovery occurs.
Phenomenon of Cavitation is experienced in CV and PUMPS

32. CAVITATION DP P1 P2 PV PVC’ Valve Inlet Trim Exit Valve Outlet Trim
Vena
Contracta

33. CAVITATION DAMAGE

34. CAVITATION CONTROLS SYSTEM DESIGN 1. LOCATION OF VALVE 2. CASCADING
MATERIAL SELECTION
HARDEN MATERIAL,
LIKE 17-4 pH, 440C, 420SST HT
AND 316/COLMONOY 6 / ALLOY 6

35. CAVITATION CONTROLS ANTI - CAVITATION PRODUCTS
CCI DRAG DESIGN, UP TO 380 BAR PRESS. DROP.
FISHER CAVITROL - III DESIGN
CAVITROL - III WITH 1 STAGE- UP TO 99 BAR.
CAVITROL - III 2-3 STAGES- 99 TO 207 BAR.
CAVITROL -4 , ABOVE 200 BAR, SIZE LIMIT 2” TO 6”.
ABB INTROL DESIGN

36. CAVITATION CONTROLS :- FISHER CAVITROL DESIGN
CAVITROL - III CAVITROL - III
STAGE STAGE - 3

37. CAVITATION CONTROLS :- FISHER CAVITROL DESIGN

38. CAVITATION CONTROLS :- ABB INTROL DESIGN
INTROL CAGE

39. CAVITATION CONTROLS :- CCI DRAG DESIGN
CCI DRAG CAGE

40. CAVITATION CONTROLS :- CCI DRAG DESIGN

41. CAVITATION CONTROLS :- CCI DRAG DESIGN

42. CHOKED FLOW Choked flow :-
Formation of vapour bubbles in the liquid flow stream cause a crowding condition at the vena contracta which tends to limit flow through the valve.
If valve pressure drop is increased slightly beyond the point where bubbles begins to form, a choked flow condition is reached. With constant upstream pressure, further increase in pressure drop will not produced increased flow through the valve.

43. NOISE FUNDAMENTALS
Noise :- A random mixture of sound pressure waves of various amplitudes and frequency. Which people do not like to hear.
Sound Wave :- A pressure wave with a fixed frequency and amplitude traveling through a medium.
Unit of Noise :- dBA ( Decibels )= 20 Log( Existing sound pressure level / microbars )
Source of valve noise:
Mechanical Noise :- It produces high mechanical stress - fatigue failure of vibrating part Mechanical noise can be solved by improved design to suppress vibration by good guiding and rugged construction.
Vibration of valve components :- This is due to lateral movement of valve plug relative to guide surfaces. The sound level produce normally will have frequency less then 1500Hz and is describe as metallic rattling.
Fluid impingement upon the movable of flexible part ( Metallic chattering )
Components resonates at its own natural frequency ( single tone 3KHz to 7KHz)
Hydrodynamic Noise :- It is due to cavitation. It is because of implosion of vapor bubbles and is relatively low.

44. NOISE FUNDAMENTALS Aerodynamic Noise :-
Highest energy component at same frequency where human ear is most sensitive. Large amount of energy converted to aerodynamic noise.
High intensity noise resulting due to turbulent flow of gas, are due to high relative velocity.
This can be classified as non-periodic or random noise with occurring frequency between KHz to 8 KHz.
Valve pressure drop ( Main source ),
Obstruction in flow path,
Valve style , having more flow directional changes,
Degree of turbulence varies with valve style1,
Valve size.

45. PERMISSIBLE EXPOSURE DURATIONS NOISE LEVEL
OSHA :- OCCUPATIONAL SAFETY AND HEALTH ACT
DEFINES CRITERIA FOR PERMISSIBLE EXPOSURE DURATIONS NOISE LEVEL
IN JAMNAGAR COMPLEX MAX. 85 dBA IS CONSIDERED AS A VALVE SELECTION CRITERIA.

46. NOISE CONTROL PATH TREATMENT INSULATION OF PIPE HEAVY WALLED PIPE
SILENCER
SOURCE TREATMENT
VALVE CAGE STYLE ( TRIM )
WHISPER - I ( DP/P1 <= 0.65 ), Noise reduction up to 18 dBA.
WHISPER - III ( 0.6 <= DP/P1 <= 0.99 ), Noise reduction up to 30 dBA.
WHISPERFLO (NEW DESIGN), Noise reduction up to 10 dBA.
BY INLINE DIFFUSER
BY WHISPER DISK

47. NOISE CONTROL - SOURCE TREATMENT
WHISPER - III DESIGN
WHISPER - I DESIGN

48. NOISE CONTROL - SOURCE TREATMENT
WHISPERFLO DESIGN BY FISHER

49. NOISE CONTROL - SOURCE TREATMENT
WHISPER DISK AND IN LINE DIFFUSER DESIGN BY FISHER

50. NOISE CALCULATION SPL = SPLP + SPLCG + SPLP/P1 + SPLK + SPLP2
SPL = OVERALL NOISE LEVEL IN DECIBLE ( 1 METER DOWNSTREAM OF VALVE OUTLET AND 1METER FROM THE PIPE SURFACE )
SPLP = FUNCTION OF PRESSURE DROP ACROSS THE VALVE ( MAJOR COMPONENT )
SPLCG = GAS SIZING COEFFICIENT ( MAJOR COMPONENT )
SPLP/P1 = RATIO OF PRESSURE DIFFERENTIAL TO INLET PRESSURE
SPLK = CORRECTION IN DBA FOR PIPE SIZE AND SCHEDULE
SPLP2 = DOWNSTREAM PRESSURE
SIMPLIFIED EQUATION ( WITHOUT MUCH LOSS OF ACCURACY ) :
SPL = SPLP + SPLCG

51. CONTROL VALVE GLAND PACKING

52. CONTROL VALVE GLAND PACKING

53. VALVE MATERIAL
Essentially material for the valve is valve assembly MOC. Standard material commonly used can be listed as below -
Valve Body & Bonnet - As per Process
Internals - As per Process . Commonly SS316 with or w/o stellite.
Valve Gasket - Graphite, Metallic SS 316 or SS 316L
Valve Packing - Commonly Teflon Or Graphite
Fasteners - B7 or B8M
Actuator Yoke - Cast Iron
Actuator Spring - Spring Steel
Actuator Diaphragm - Nitrile Rubber with fabric reinforcement
Accessories - Commonly Aluminum.

54. TECHNOLOGY
With the advent of new technology Control Valve has undergone rapid change in terms of change in Internals, Capacity Increase, Guiding, Leakage Class Improvement, Treatment of Noise And Cavitation And Finally DIGITAL.
About 30 years back control valves were only available with top guided or top & bottom guided design with asbestos packing and practically no solution available for Hi Pressure drop application leading to Noise for Gas service Or Cavitation for Liquid Service.

55. TECHNOLOGY
Now a days we are also having control valve with digital technology, where valve positioner is digital in nature and able to provide PID function at the valve itself. Digital positioner can provide the following apart from acting as interface between controller and valve actuator -
1. Provide HART feedback.
2. Can couple with Foundation Fieldbus.
3. Can provide valve diagnostics.
4. Helps in Asset Management.
5. Provide lock, soft alarms and data logging facilities.
6. Can achieve split action, remote calibration etc.

56. Trouble Shooting in Control Valves.

57. Trouble Shooting in Control Valves.

58. Trouble Shooting in Control Valves.

59. Trouble Shooting in Control Valves.

60. Trouble Shooting in Control Valves.

61. THANK YOU