1. V ALVES I N I NDUSTRY (P ART 1) by ANIS ATIKAH BINTI AHMAD

2. QUESTION (1) In general, valves can be classified into: (2) According to function, valve can be classified into: (3) According to application, valve can be classified into: (4) According to motion, valve can be classified into: 2 ERT 213/3 Process instrumentation

3. I NTRODUCTION TO V ALVES Mechanical devices specifically designed to direct, start, stop, mix or regulate the flow, pressure or temperature of a process fluid. Manufactured from various materials, mostly made from steel, iron, plastic, brass, bronze and special alloys. 3

4. V ALVES C LASSIFICATION A CCORDING T O ; 1) Function 2) Application 3) Motion 4

5. V ALVES C LASSIFICATION A CCORDING T O F UNCTION Categorized into three areas: i) On-Off Valves ii) Non return Valves iii) Throttling Valves Specific valve-body designs may fit into one, two, or all three category. Example: plug valve may be used for on-off service, or with addition of actuation, may be used as a throttling control valve. 5

6. V ALVES C LASSIFICATION A CCORDING T O F UNCTION 1) On-Off Valves  Start or stop the flow of the medium through the process.  Example: gate, plug, ball and pressure-relief valves.  Can be hand-operated or automated with the addition of an actuator. 6

7. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (O N -O FF V ALVES ) 7

8.  Used in mixing applications where a number of fluids are combined for a predetermined amount of time.  Used for immediate shut down of a system when an emergency situation occurs. 8

9. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (O N -O FF V ALVES )  Pressure-relief valves are self-actuated on-off valves that open only when a preset pressure is surpassed.  Relief Valves: Used for guarding against overpressurization of a liquid service.  Safety Valve Applied in gas applications where overpressurization of the system shows a safety or process hazard and must be vented. 9

10. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (O N -O FF V ALVES ) 10

11. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (O N -O FF V ALVES ) 11

12. V ALVES C LASSIFICATION A CCORDING T O F UNCTION 2) Non return Valves  Allow the fluid to flow only in the desired direction.  Any flow or pressure in the opposite direction is mechanically restricted from occurring.  All check valves are non return valves. 12

13. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (N ON - RETURN V ALVES ) 13

14. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (N ON - RETURN VALVES )  Used to prevent backflow of fluid which could damage equipment or upset the process.  Useful in protecting a pump in liquid applications or a compressor in gas applications from backflow when the pump or compressor is shut down.  Applied in process systems that have varying pressures, which must be kept separated. 14

15. V ALVES C LASSIFICATION A CCORDING T O F UNCTION 3) Throttling Valves  Used for regulating the flow, temperature or pressure of the service.  Can be moved to any position within the stroke of the valve and hold that position, including the fully-open or fully-closed positions. 15

16. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (T HROTTLING VALVES )  Example : pressure regulator varies the valve’s position to maintain constant pressure downstream (close to decrease and open to increase the pressure). 16

17. V ALVES C LASSIFICATION A CCORDING T O F UNCTION (T HROTTLING V ALVES ) 17

18. V ALVES C LASSIFICATION A CCORDING T O A PPLICATION Categorized into three : 1) General Service Valves 2) Special Service Valves 3) Severe Service Valves 18

19. V ALVES C LASSIFICATION A CCORDING T O A PPLICATION 1) General Service Valves  Designed for the majority of the commonplace applications that have lower-pressure ratings, moderate- temperature ratings, noncorrosive fluids and common pressure drops that do not result in cavitation or flashing.  Have some degree of interchangeability and flexibility for wider range of applications. 19

20. V ALVES C LASSIFICATION A CCORDING T O A PPLICATION 2) Special Service Valves  Designed for a single application that is outside normal process applications (custom- engineered valves).  Usually handle a demanding temperature, high pressure or a corrosive medium. 20

21. V ALVES C LASSIFICATION A CCORDING T O A PPLICATION 3) Severe Service Valves  Equipped with special features to handle volatile applications such as high pressure drops.  Special actuation may be required to overcome the forces of the process. 21

22. V ALVES C LASSIFICATION A CCORDING T O M OTION Categorized into two : 1) Linear-motion Valves 2) Rotary-motion Valves 22

23. V ALVES C LASSIFICATION A CCORDING T O M OTION 1) Linear-motion Valves  Have a sliding-stem design that pushes a closure element into an open or closed position.  Simple design, easy maintenance, and versatile with various sizes, pressure class and design options.  Example: gate, globe, diaphragm, three- way valves. 23

24. V ALVES C LASSIFICATION A CCORDING T O M OTION ( LINEAR - MOTION VALVES ) 24

25. V ALVES C LASSIFICATION A CCORDING T O M OTION 2) Rotary-motion Valves  Used a closure element that rotates through a quarter-turn or 45 ⁰ range to open or block the flow.  Limited to certain pressure drops.  Prone to cavitations and flashing problems. 25

26. V ALVES C LASSIFICATION A CCORDING T O M OTION (R OTARY - MOTION VALVES ) 26

27. 27 THANK YOU…

28. 28 ASSIGNMENT 1