Valves classification and description (1).pdf
- 1. VALVES CONTREN Series # 40109-07
- 2. 1.0.0 Introduction • Valves are devices that control the flow of fluids or gases through a piping system. • Valves are made of a wide variety of materials for compatibility to the fluid flowing through it.
- 3. 2.0.0 Valves That Start and Stop Flow • These valves are designed to be operated completely open or completely closed. • These valves cannot be used effectively to throttle, or regulate, flow. • Gate Valve • Knife Valve • Ball Valve • Plug Valve • Three-Way Valve
- 4. 2.1.0 Gate Valve • Turning the hand-wheel lifts or lowers the disc (gate). • A partially opened gate causes turbulence. • This turbulence not only causes piping damage (water hammer), it also wears the disc and seat surfaces.
- 5. 2.1.0 Gate Valve – Solid Wedge Most common used: a single, solid disc that is rugged and simple.
- 6. 2.1.0 Gate Valve – Flexible Wedge A one-piece disc with a cut or groove around the edge to compensate for irregular sealing edges.
- 7. 2.1.0 Gate Valve – Split Wedge Self- adjusting and self- aligning discs.
- 8. 2.1.0 Gate Valve – Double (Parallel) Disc Prevents valve binding due to thermal transients.
- 9. 2.1.1 Valve Stem • Connects the hand-wheel to the gate. • Rising stem – Hand-wheel and stem rising when opening • Non-rising stem – Hand-wheel and stem do not rise while opening • Outside screw-&-yoke (OS&Y) – Stem rises through the hand-wheel while opening – Stem does not contact the fluid; • therefore, the OS&Y is suitable for corrosive fluids
- 10. 2.1.1 Valve Stem Rising Stem Non-Rising Stem OS&Y Stem
- 11. 2.2.0 Knife Gate Valve • Gate is thin with tapered edge on the bottom • Suited for slurry, pulp, waste, and low- pressure applications
- 12. 2.3.0 Ball Valve • Gate is a ball with a hole for flow through it matching the pipe size
- 13. 2.4.0 Plug Valve • Similar to the ball valve, • It is a ¼-turn start-stop valve. • Sealant is plug shaped.
- 14. 2.5.0 Three-Way Valve • A multi-port plug valve installed at the intersection of 3 lines.
- 15. 3.0.0 Valves That Regulate Flow • These valves can not only start and stop flow, they can regulate flow. • The disc can be totally removed from the flow. • The most common types are: – Globe Valve – Butterfly Valve – Diaphragm Valve
- 16. 3.1.0 Globe Valve • Valve movement is perpendicular to the seat. • Basic types: – Angle – Y-type – Needle
- 17. 3.1.0 Angle Valve • A globe valve that changes the direction of flow. • Usually, the ports are at 90-degrees to each other. • These are commonly used to replace valve and elbow combinations.
- 18. 3.1.0 Y-Type Valve • Has the straight-through flow of a gate valve. • Has the throttling and flow control of a globe.
- 19. 3.1.0 Needle Valve • Commonly used for precise flow control of instrumentation applications. • Not commonly available over 1” in size.
- 20. 3.2.0 Butterfly Valve • Has a round disc that turns 90 degrees to mate with the seat. • Used in low-to-medium pressures and flows.
- 21. 3.2.1 Wafer Valve • Butterfly valve that sandwiches between two flanges.
- 22. 3.2.2 Wafer Lug Valve • Butterfly valve that sandwiches between two flanges and has lugs to match the bolt holes of the flange.
- 23. 3.2.3 Two-Flange Valve • The body has a flange cast on both sides.
- 24. 3.3.0 Diaphragm Valve • Sealing disc is flexible and seals against the body. • Suitable for slurries, highly corrosive materials, and materials that cannot be contaminated.
- 25. 3.4.0 Needle Valve • Has a tapered needle instead of a disc to allow for fine adjustment to the flow.
- 26. 4.0.0 Valves That Relieve Pressure • Used to control pressure, not flow. • Two basic types are: – Safety Valve – Pressure Relief Valve
- 27. 4.1.0 Safety Valve • Used in pipelines and tanks to prevent ruptures due to excess pressure. Water Hydraulic (Sectional View) Pneumatic
- 28. 4.2.0 Pressure Relief Valve • In-line valve to control a specified pressure in the liquid circuit. • These usually have the pressure set at the factory.
- 29. 5.0.0 Valves That Regulate Direction of Flow • These valves prevent backflow and are referred to as “check valves”. • Common types are: – Swing – Lift – Ball – Butterfly – Foot
- 30. 5.1.0 Swing Check Valve • Uses a hinged disc as the sealing member.
- 31. 5.2.0 Lift Check Valve • A one-way-flow check valve that functions like a globe valve.
- 32. 5.3.0 Ball Check Valve • Much like a lift check except that it uses a ball instead of a disc for sealing.
- 33. 5.4.0 Butterfly Check Valve • Two disc hinged in the middle.
- 34. 5.5.0 Foot Valve • Used at the bottom of a suction line to maintain the prime of the pump.
- 35. 6.0.0 Valve Actuators • Two primary purposes of valve actuators: – Provide automatic operation of the valve, – Reduce the effort required to manually operate the valve. • Four basic types of actuators: – Gear – Chain – Pneumatic or Hydraulic – Motor Driven, Electric or Pneumatic.
- 36. 6.1.0 Gear Actuators • Reduces the effort required to manually operate the valve. • Three basic types: • Spur Gear, • Bevel Gear, • Worm Gear.
- 37. 6.1.1 Spur Gear Actuator • Valve stem and driver shaft are parallel.
- 38. 6.1.2 Bevel Gear Actuator • Valve stem and driver shaft are 90 degrees to each other and the gears are cone-shaped.
- 39. 6.1.3 Worm Gear Actuator • Valve stem and driver shaft are 90 degrees to each other. The driver gear (worm) looks like a screw. • Used primarily with butterfly valves.
- 40. 6.2.0 Chain Actuators • Reduces the effort required to manually operate the valve. • Applicable where the valve is not easily accessible; such as, too high to reach.
- 41. 6.3.0 Pneumatic and Hydraulic Actuators • Uses fluid or air pressure to actuate the valve. • Most of these are spring-loaded to ensure that the valve fails in a fail-safe position.
- 42. 6.4.0 Electric- or Air-Motor Driven Actuators • Uses motors to actuate the valve. • Motor can be either electrical or pneumatic.
- 43. 6.5.0 Control Valves • Variations of the angle, globe, or ball valves that are controlled by pneumatic, electronic, or hydraulic actuators. • Most commonly used for pressure or temperature control.
- 44. 7.0.0 Storing and Handling Valves • Regardless of the size of the valve, the internal seats, valves, and springs are precision machined and must be handled carefully to avoid damage.
- 45. 7.1.0 Safety Considerations • When handling and/or working around valves: – Be aware of all pinch points, – Do not stand under a load, – Be aware of surroundings, – Never operate a valve in a live system without authorization, – Use a spud wrench, not your finger, to align flange bolt holes. – Never stand in front of a safety relief valve discharge.
- 46. 7.2.0 Storing Valves • Label all valves. • Never store valves on the ground. • Cover all open ends with ‘end protectors’.
- 47. 7.3.0 Rigging Valves • Protect all threads and ends. • Use the proper rigging equipment. • Connect rigging to body only, not the stem, handle, or through openings. • Use a tag line, especially for larger valves.
- 48. 8.0.0 Installing Valves • Best working height for manual actuator is between 2’0” and 4’6” from floor. • Follow schematics exactly. – Direction of flow. – Stem position. • (vertical up works best, horizontal is acceptable, never position stem vertical down.)
- 49. 9.0.0 Valve Selection, Types, and Applications • Valves can be used in many different applications. • Valve selection is important; therefore, follow design requirements exactly at installation.
- 50. 9.1.0 Valve Selection • Important factors: • Temperature. • Pressure. • Pipe size. • Fluid chemistry. • Valve function.
- 51. 10.0.0 Valve Markings and Nameplate Information • Manufacturers Standardization Society (MSS): – Developed standards for valve markings. • American National Standards Institute (ANSI): • American Society for Testing Materials International (ASTM): – Both have adopted the MSS marking system.
- 52. 10.0.0 Valve Markings and Nameplate Information • Bridgewall markings (globe valves): – Indicates how the valve seat is angled in relation to the inlet and outlet ports. • Flow direction arrow: – Proper direction of fluid flow.
- 53. 10.1.0 Rating Designation • Pressure and temperature rating. • Fluid types and other pertinent data.
- 54. 10.2.0 Trim Identification • Identifies the material of the seat, disc, stem, and other internal parts if they are different from the body of the valve.
- 55. 10.3.0 Size Designation • Indicates the numerical identification associated with the pipe size of the connecting ends.
- 56. 10.4.0 Thread Markings • Identifies the size and type of threads for valves that have threaded connections.
- 57. 10.5.0 Valve Schematic Symbols • Valves are shown on schematics by symbols.