easy to understand about control valve.

1. CONTROL VALVE
NAME : RESHVHIN RAJ JEEWA
DATE : 28/06/2016

2. Contents
1. WHAT IS CONTROL VALVE ?.....................................................................................3
2. CONTROLVALVE CLASSIFICATION .......................................................................4
3. LINEAR MOTION (CONTROLVALVE).....................................................................5
4. GLOBE VALVE - (LINEAR MOTION)........................................................................6
5. DIAPHRAGM VALVE - (LINEAR MOTION).............................................................9
6. PINCH VALVE - (LINEAR MOTION).......................................................................10
7. ROTARY MOTION.......................................................................................................11
8. BALL VALVE (ROTARY MOTION)............................................................................12
8. BUTTERFLY VALVE (ROTARY MOTION)...............................................................13
9. ACTUATORS................................................................................................................14
10. PNEUMATIC ACTUATOR........................................................................................14
11. ELECTRIC ACTUATOR...........................................................................................18

3. 1. WHAT IS CONTROL VALVE ?
 A Control Valve is a power -operated device used to modify the fluid
flow rate in a process system.
 There are two basic types of control valves:
- TYPE A : Rotary motion valve having ball, butterfly or plug type
closures.
- TYPE B : Linear motion valvehaving globe, diaphragm or pinch type
closures.
 Control valveis controls and distributes pressure, flow, level,
temperature and etc.

4. 2. CONTROL VALVE CLASSIFICATION
Reference: Control Valve Classification.

5. 3. LINEAR MOTION (CONTROL VALVE)
TYPES OF CLOSURE :
 Globe :
- Single Seated
- Double Seated
- Three way
 Diaphragm
 Pinch
LINEAR VALVEFEATURES :
 Tortuous flow path.
 Low recovery.
 Can throttle small flow rates.
 Offers variety of special tri designs.
 Suited to high-pressureapplication.
 Usually flanged or threaded.
 Separable bonnet.

6. 4. GLOBE VALVE - (LINEAR MOTION)
Single Seated Globe Valve
Features :
 Large amountof force required to drivethe stem.
 Tight shut off.
 Used in small diameter applications.
Application:
 Used for controlling large rangeof process parameters hanceused in oil
and gas production, power generation.

7. Double Seated Globe Valve
Features :
 Steam can be driven with small amountof force.
 Can not achieve perfect closureresulting in leakage.
 Used in larger diameter application.
 Body parts wear out due to erosion and cavitations which result in
annoying noises.
Application:
 Used for high flow and high pressureservices.

8. Three Way Valve
Features :
 High flow capacity.
 Valve used for mixing and diverting liquids.
 High rangeability.
 Leakage capability consistentwith normal single seated globe valve.
Application:
 Used in textile industries.

9. 5. DIAPHRAGM VALVE - (LINEAR MOTION)
Features :
 Consists of a saddle or seat upon which the diaphragm closes the valve.
 Can handle corrosivefluids.
Application:
 Used as shutoff valves in food and beverage, pharmaceutical and
biotech industries.

10. 6. PINCH VALVE - (LINEAR MOTION)
Features :
 Tight shut off.
 The flexible sleeve allows the valveto closedrop tight around solids,
solids that would typically be trapped by the seat or stuck in crevices in
globe, diaphragm, butterfly, gate, or ball valves.
Application:
 Best used in controlling corrosivefluids, steamand high pressure.

11. 7. ROTARY MOTION
TYPES OF CLOSURE :
 Ball
 Butterfly
 Plug
ADVANTAGES AND DISADVANTAGES OF ROTARY MOTION :
ADVANTAGES DISADVANTAGES
 Low weight.  Generally not suitable below 1 to 2
inches.
 Simple design.  Operating shaft mustbe designed to
supporta fairly heavy side-thrust.
 High relative .  Leakage problem.
 More reliable.
 Low initial cost.
 Friction-free packing.

12. 8. BALL VALVE (ROTARY MOTION)
Features :
 Tight shut off.
 Minimum obstruction for the flowing media.
 High flow capacity.
 Can withstand high pressureand temperatures.
Application:
 Used for hazardous and corrosivefluids.

13. 8. BUTTERFLY VALVE (ROTARY MOTION)
Features :
 High flow capacity.
 Unlike ball valve the disc is present in the flow of the liquid and hence a
pressuredrop is always induced in the flow.
 Tight shut off.
Application:
 Used in steel, suger and textile industries.

14. 9. ACTUATORS
 An actuator is a componentof machines that is responsiblefor moving
or controlling a mechanismor system. An actuator requires a control
signal and sourceof energy.
 The control signal is relatively low energy and may be electric voltage or
current, pneumatic or hydraulic pressure, or even human power.
THE MAJOR TYPES OF ACTUATOR ARE:
1. Pneumatic type
2. Electric type
10. PNEUMATIC ACTUATOR
BASICALLY HAVETWO TYPES :
1. Piston actuator.
2. Diaphragm actuator.

15. PISTON ACTUATOR
 They can withstand higher input pressure.
 Can offer small cylinder volumes.
 They are generally used where the strokeof a diaphragm actuator would
be too shortor the thrustis too small.

16. DIAPHRAGM ACTUATOR
 Compressed air applied to a flexible membrane called the diaphragm.
 This actuator is a single acting becauseair is supplied fromsingle side of
the diaphragm.

18. 11. ELECTRIC ACTUATOR
 Electric actuators usean electric motor with voltage requirements in the
following range: 230 Vac, 100 Vac,24 Vac and 24 Vdc.
 There are two types of electric actuator :
1. VMD (valve motor drive).
2. Modulating.
VMD (Valve Motor Drive)
 Electric actuator has three stages :
I. Driving the valve open.
II. Driving the valve closed.
III. No movement.

19. MODULATING
 In order to position the controlvalve in responseto the system
requirements a modulating actuator can be used.
 Ithas positioning circuit .
 This actuator also has position sensor.