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UNIVERSIT Á DEGLI STUDI DI SALERNO

Bachelor Degree in Chemical Engineering Course: Process Instrumentation and Control ( Strumentazione e Controllo dei Processi Chimici ) VALVE TECHNOLOGY CLASSIFICATIONS AND CONSTRUCTION CHARACTERISTICS OF VALVES Rev. 4.1 of April 04, 2019. UNIVERSIT Á DEGLI STUDI DI SALERNO. INTRODUCTION.

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UNIVERSIT Á DEGLI STUDI DI SALERNO

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  1. Bachelor Degree in Chemical Engineering Course: Process Instrumentation and Control (Strumentazione e Controllo dei Processi Chimici) VALVE TECHNOLOGY CLASSIFICATIONS AND CONSTRUCTION CHARACTERISTICS OF VALVES Rev. 4.1 of April 04, 2019 UNIVERSITÁ DEGLI STUDI DI SALERNO

  2. INTRODUCTION • The requirement to regulate and control the flow rate of fluids in hydraulic circuits is very common in industrial processes. • It occurs in energy and steam production, control of level and pressure in tanks containing liquid and gas, control of temperature in rooms and pipes, control of chemical composition of a specified product. • The final control elements used to regulate the flow rate of fluids are valves and pumps. • The selection of the valve type, its characteristics and the proper design can significantly affect the performance of a control system. Process Instrumentation and Control - Prof. M. Miccio

  3. INTRODUCTION VALVE DEFINITION A mechanical device that is used in a fluid power system, which is used to provide some change of state of the fluid. from http://www.engnetglobal.com/tips/glossary.aspx?search=valve GENERAL SYMBOL for VALVES CONTROL VALVE DEFINITION A valve that modulates the flow of fluid in a conduit in response to a signal from a process measurement control system. From http://www.answers.com/topic/control-valve Process Instrumentation and Control - Prof. M. Miccio

  4. Body Closure member Actuator (device, external to the body, that supplies force and motion to a valve closure member) Joints VALVES: COMPONENTS Process Instrumentation and Control - Prof. M. Miccio

  5. VALVES: COMPONENTS COMPRESSED AIR taken from: Magnani, Ferretti e Rocco (2007) ACTUATOR MEMBRANE SPRING STEM BODY schematic drawing CLOSURE MEMBER SEAT INGOING FLUID OUTGOINGFLUID JOINTS Process Instrumentation and Control - Prof. M. Miccio

  6. Valves have the function of: ON/OFF or ISOLATING: valves having two positions: In the one position the passage of a fluid is stopped (with a leak-tight seal). In the other position flow is allowed with a low pressure drop DIVERT SERVICE: valves having two positions, which never block flow: In the one position flow is allowed from the common port to port A. In the other position flow is allowed form the common port to port B THROTTLING: in order to regulate the fluid flow rate by changing the position of the closure member PRESSURE–REGULATING: in order to regulate pressure of gas and steam SAFETY/PRESSURE RELEASE: in order to prevent the overcoming of a hazardous pressure for structural resistance of piping and equipment CHECK VALVE: to allow the one way flow of a fluid only 1st CLASSIFICATION OF VALVES(based on FUNCTION) Process Instrumentation and Control - Prof. M. Miccio

  7. VALVE FUNCTIONS:EXAMPLES Check valve Safety valve ON/OFF valve Divertvalve normalizedsymbolsectiondrawing Process Instrumentation and Control - Prof. M. Miccio

  8. BIB COCK (NPS <= 1") GATE VALVES (and BIB COCKS) GLOBE VALVES (and BIB COCKS) VALVES FOR PARTICULAR/SPECIAL USES 2nd CLASSIFICATION OF VALVES(based on SIZE and/or EXTERNAL SHAPE ) Process Instrumentation and Control - Prof. M. Miccio

  9. BIB COCK (NPS <= 1") GATE VALVES GLOBE VALVES VALVES FOR PARTICULAR/SPECIAL USES 2nd CLASSIFICATION OF VALVES(based on size and/or external shape ) Process Instrumentation and Control - Prof. M. Miccio

  10. EXAMPLE OF BIB COCK (for REGULATION) Process Instrumentation and Control - Prof. M. Miccio

  11. BALL VALVE/COCK (for ON/OFF) The ball valve is the most common device for ON/OFF switch of a flow in pipes. It operates by means of the 90° rotation of a spherical closure member in a cylindrical cavity, coaxial to the flow. This valve allows the full closure/opening and, to some extent, the pressure-regulation of the flow. SCHEMATIC DRAWING SIDE VIEW TOP VIEW CUTAWAY DRAWING Process Instrumentation and Control - Prof. M. Miccio

  12. “MODULATING” BALL VALVE(for THROTTLING)with REGULATION function SCHEMATIC DRAWING CUTAWAY PICTURE Process Instrumentation and Control - Prof. M. Miccio

  13. EXAMPLE OF “MODULATING” BALL VALVE CUTAWAY PICTURE Process Instrumentation and Control - Prof. M. Miccio

  14. PLUG VALVES/COCKS(conically-tapered or cylindrical) • TWO-PORT CONICALLY-TAPERED PLUG COCK (NPS ≤ 1“) SIDE VIEW TOP VIEW SCHEMATIC DRAWING • TWO-PORT CYLINDRICAL PLUG COCK (NPS ≤ 1“) Process Instrumentation and Control - Prof. M. Miccio

  15. MULTI-PORT COCKS(spherical, cylindrical, conically-tapered)NPS ≤ 1“ FOUR-PORT PLUG COCK THREE-PORT PLUG COCK SECTIONAL VIEW FROM TOP SCHEMATIC DRAWING PICTURE Process Instrumentation and Control - Prof. M. Miccio

  16. BUTTERFLY COCK SCHEMATIC DRAWING ANIMATED DRAWING PICTURE SIDE VIEW FRONTAL VIEW TOP VIEW Process Instrumentation and Control - Prof. M. Miccio

  17. BUTTERFLY VALVE Picture Photograpicdrawing Process Instrumentation and Control - Prof. M. Miccio

  18. BUTTERFLY VALVE (DN 32-1200) Construction details: Body and flanges; stem extension for the insulation. Stem with position indicator. Disk. Interchangeable hose. Plain bearing. Lap-jointed disk. External gasket. Anti-ejection gasket. CUTAWAY DRAWINGS WAFER TYPE Process Instrumentation and Control - Prof. M. Miccio

  19. BUTTERFLY VALVE WAFER TYPE Process Instrumentation and Control - Prof. M. Miccio

  20. BIB COCK (NPS <= 1") GATE VALVES GLOBE VALVES VALVES FOR PARTICULAR/SPECIAL USES 2nd CLASSIFICATION OF VALVES(based on size and/or external shape ) Process Instrumentation and Control - Prof. M. Miccio

  21. EXAMPLES OF GATE VALVES(for ON/OFF) • They are ON-OFF. • The opening diameter for the fluid flow is almost equal to the pipingdiameter • The main flow direction is not subjected to any change inside the valve • A completely open gatevalve introduces a very small pressuredrop Picture Process Instrumentation and Control - Prof. M. Miccio

  22. GATE VALVES AND COCKS SCHEMATIC DRAWING Construction drawing Process Instrumentation and Control - Prof. M. Miccio

  23. BIB COCK (NPS <= 1") GATE VALVES GLOBE VALVES VALVES FOR PARTICULAR/SPECIAL USES 2nd CLASSIFICATION OF VALVES(based on size and/or external shape ) Process Instrumentation and Control - Prof. M. Miccio

  24. GLOBE VALVES and COCKS GENERAL EXAMPLES S – STEM T – PLUG V – PORT B – BODY F – JOINTS P - GASKET Animated drawing Construction drawing 3D drawing NOTES: They operate for THROTTLING. They are the most well known valves and named as “globe” because their bodywas formerly spherical. Process Instrumentation and Control - Prof. M. Miccio

  25. GLOBE VALVES (NPS>1”) SPECIAL EXAMPLES Guided-flow valve or Z-body globe valve Free-flow valve or Y-body globe valve Automatic globe valve with float Process Instrumentation and Control - Prof. M. Miccio

  26. ANGLE VALVE BOTTOM VALVE STRAIGTH-FLOW VALVE 3rd CLASSIFICATION OF VALVES(based on the position/coupling with the pipingin the process) NOTE: The bodies of valves have an arrow indicating the direction of the flow. For bidirectional valves, such as butterfly, globe and gate valves, no indication is reported. Process Instrumentation and Control - Prof. M. Miccio

  27. ANGLE GLOBE VALVE Body Bonnet Closure member Seat Stem Handwheel Gland nut Process Instrumentation and Control - Prof. M. Miccio

  28. BOTTOM GLOBE VALVE Constructivedrawing Process Instrumentation and Control - Prof. M. Miccio

  29. BIB COCK (NPS <= 1") GATE VALVES GLOBE VALVES VALVES FOR PARTICULAR/SPECIAL USES 2nd CLASSIFICATION OF VALVES(based on size and/or external shape ) Process Instrumentation and Control - Prof. M. Miccio

  30. diaphragm valve(or membrane or pinch VALVE) Schematic drawing Animated drawing Section drawing WEIR VALVE Guided-flow Free-flow NOTE: The throttling and the hermetic seal are directly performed by the compression of an elastic or plastic membrane on the body of the valve P.K.Saunders invented and patented weir valve diaphragm valves over 60 years ago HOSE VALVE Process Instrumentation and Control - Prof. M. Miccio

  31. diaphragm valve(or membrane or pinch VALVE) HOSE VALVE SECTION Closed Process Instrumentation and Control - Prof. M. Miccio

  32. VENTING VALVES for GASES Venting valvewith direct weight Lifting force: for P<PlimF = (P - Prif)S < Flim S = flow passage area (port) P Prif Venting valvewith counterweight Springventing valve Process Instrumentation and Control - Prof. M. Miccio

  33. RUPTURE DISK for GASES Pictures Construction drawing Process Instrumentation and Control - Prof. M. Miccio

  34. CHECK VALVES “Clapet” check valve Guided-flowcheck valve Free-flowcheck valve Vertical check valve Schematic drawing Process Instrumentation and Control - Prof. M. Miccio

  35. ROTARY VALVES for bulk solids Exploded view drawing ☞ A motorisrequired Process Instrumentation and Control - Prof. M. Miccio

  36. ROTARY VALVES for bulk solids Animated drawing Operating scheme Process Instrumentation and Control - Prof. M. Miccio

  37. 4th CLASSIFICATION OF VALVES(based on the shape of the CLOSURE MEMBER) DISK VALVE CAP VALVE PISTON VALVE NEEDLE VALVE CAGE VALVE V-PORT GATE VALVE BUTTERFLY VALVE PLUG VALVE (spherical, cylindrical, conically-tapered) Globe valve Process Instrumentation and Control - Prof. M. Miccio

  38. CLOSURE MEMBERS DISK CLOSURE MEMBER The increase of the flowrate occurs almost exclusively in the first part of the opening , after which further increase of flowrate are almost negligible. For this reason, the disk closure member is also formerly known as quick opening. It is commonly used for on/off function. LINEAR CLOSURE MEMBER In this case a linear relation between the opening of the valve and the flowrate. The shape of the closure member is usually parabolic. Closure members with a linear characteristic are used when the operating pressure drop or flowrate do not change significantly with the time during the process. EQUAL PERCENTAGE CLOSURE MEMBER In this case for a constant increase of the trim travel we have an equal percentage increase of the flowrate, for the same pressure drop. Considering and increase of 10% of the opening, the flowrate increases about 50% of the initial flowrate. It follows that the most increase of flowrate of the valve occurs in the last part of the travel of the closure member. The equal percentage closure members are used when most of the pressure drop is localized in the plant and only the lower part occurs crossing the valve. They are also suggested when the flowrate and the operating pressure drop are subjected to significant changes during the process. see also: § 13.5 - Stephanopoulos, “Chemical process control: an Introduction to theory and practice”, Prentice Hall, 1984 Process Instrumentation and Control - Prof. M. Miccio

  39. CLOSURE MEMBERSIN THROTTLING GLOBE VALVES taken from: Magnani, Ferretti e Rocco (2007) Process Instrumentation and Control - Prof. M. Miccio

  40. NEEDLE VALVE Picture Process Instrumentation and Control - Prof. M. Miccio

  41. CAGE VALVE Picture Process Instrumentation and Control - Prof. M. Miccio

  42. V-PORT GLOBE VALVE ConstructiveDrawing Process Instrumentation and Control - Prof. M. Miccio

  43. 5th CLASSIFICATION OF VALVES (based on the MOVEMENT of the closure member) • LINEAR VALVES • ROTARY VALVES Process Instrumentation and Control - Prof. M. Miccio

  44. 6th CLASSIFICATION OF VALVES(based on the service provided to the fluid) • General • Corrosive • High Pressure • Severe (Noise, Cavitating, Flashing, Abrasive …) • Cryogenic • Erosive • Toxic • Slurry • Oxygen Process Instrumentation and Control - Prof. M. Miccio

  45. Summary of Valve Types and Features https://instrumentationtools.com/ Process Instrumentation and Control - Prof. M. Miccio

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