Valves
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Valves are mechanical devices that control fluid flow through pipes. The document discusses the goals, definition, components, classifications, and materials of valves. Valves are classified according to motion, function, application, and port size. Common valve types include gate valves, globe valves, ball valves, plug valves, butterfly valves, and pinch valves. The document provides details on each type of valve including their definition, application, advantages, variations, and materials. It also provides tips on installation and maintenance of valves.
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Valves
- 1. Valves Designed by: Hossam A. Hassanein
- 2. Goals Understanding the function of valves Knowing valves major components Knowing valves classification To know - Application of each valve type - Material - Installation and, Maintenance tips 2
- 3. Definition Valves are mechanical devices that control the fluids through pipes by Changing the flow rate Starting and stopping. Allowing flow in one direction only. Adjusting fluid pressure. Re-directing flow Preventing accidents by relieving overpressure 3
- 4. Valves Selection 4 Factors affecting the suitability and application of valves Fluid Properties Valve Size Valve Service Fluid Friction Loss Pressure and temperature
- 6. 6 Valves Classification According to Motion According to Function According to Application According to Port Size
- 8. 8 Valves Classification - ON-OFF (Block Valves) Gate Valve Relief Valve Plug Valve Tank-Bottom Valve Ball Valve - Non Return Valve - Throttling Valve Hand-Operated Valves Automatic Valves Valve Function
- 9. 9 Valves Classification - ON-OFF (Block Valves) Gate Valve Relief Valve Plug Valve Tank-Bottom Valve Ball Valve Used To Start or stop the flow of the medium through the process Hand-operated and can be automated with the addition of an actuator Guard against over pressurization Valve Function
- 10. 10 Valves Classification Used To Allow The Fluid To Flow Only In The Desired Direction Prevent Backflow Of Fluid - Non Return Valve Valve Function
- 11. 11 Valves Classification Used To Regulate the flow, temperature, or pressure of the service Be act as on-off valves also - Throttling Valve Hand-Operated Valves Automatic Valves Valve Function
- 13. 13 Valves Classification - General Service - Special Service - Severe Service Valve Application
- 14. 14 Valves Classification - General Service Valve Application Used For Lower-pressure ratings (16 to 100 bar.) Moderate-temperature ratings -50 to 650°F (-46 to 343°c) Non corrosive fluids, and common pressure drops that do not result in cavitation or flashing.
- 15. 15 Valves Classification - Special Service Valve Application Used For A single application that is outside normal process applications. Handling a demanding temperature, high pressure, or A corrosive medium.
- 16. 16 Valves Classification - Severe Service Valve Application Used For Handle volatile applications, such as high pressure drops
- 18. 18 Valves Classification Valve Motion - Linear-Motion Valves (Linear Valves) Gate Valve Diaphragm Valve Globe Valve Pinch Valve 3 Way and, angle Valve - Rotary-Motion Valves (Rotary Valves) Ball Valve Butterfly Valve Plug Valve
- 19. 19 Valves Classification Valve Motion - Linear-Motion Valves (Linear Valves) Gate Valve Diaphragm Valve Globe Valve Pinch Valve 3 Way and, angle Valve Have A sliding stem design that pushes A closure element into an open or closed position.
- 20. 20 Valves Classification Valve Motion - Rotary-Motion Valves (Rotary Valves) Ball Valve Butterfly Valve Plug Valve Use a closure element that rotates through a quarter-turn or 45° range to open or block the flow.
- 22. 22 Valves Classification Valve Port Size - Full-Port Valves - Reduced-Port Valves
- 23. 23 Valves Classification Valve Port Size - Full-Port Valves Closure elements to pass the flow without a significant restriction
- 24. 24 Valves Classification Valve Port Size - Reduced-Port Valves Closure Elements Restrict The Flow
- 26. 26 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Multi-turn valve in which the port is closed by A flat-faced, vertical Disk that slides at right angles Over the seat. 1- for fully open or fully Closed, non throttling service. 2- for infrequent operation. 3- for minimum resistance to flow. 4- for min. Amounts of fluid trapped in line 1- general service 2- oil, gas, air, slurries, steam 3- non condensing gases and 4- liquids , corrosive liquids 1- high capacity 2- tight shutoff 3- low cost 4- simple design and operation. 5- little resistance to flow. 1- poor flow control 2- high operating force. 3- cavities at low pressure drop. 4- must be kept in full open or full closed position. 5- throttling position will erode seat and disk 1- solid wedge 2- flexible wedge 3- split wedge 4- double disk Body Bronze, cast iron , iron Forged steel, cast steel, Stainles s steel, PVC plastic 1- lubricate or regular schedule. 2- correct packing leaks immediately. 3- always cool system when closing down a “hot” line and checking closed valves. 4- never force valves closed with wrench or pry. 5- open valves slowly to prevent hydraulic shock in line. 6- close valves slowly to help flush trapped sediment and dirt. 1- type of end connection. 2- type of wedge. 3- type of seat. 4- type of stem assembly. 5- type of bonnet assembly. 6- type of stem packing 7- operating pressure. 8- operating temperature. Trim Various Gate Valve
- 27. 27 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Quarter-turn valve that controls flow By means of cylindrical or tapered Plug with A hole through the center, Which can be positioned from open To close by A 90° turn. 1- for fully open or fully closed 2- for frequent operation. 3- for minimum resistance to flow. 4- for min. Amounts of fluid trapped in line. 5- for low press. Drop across valve 1- general service 2- slurries, 3- vapors and gases 4- liquids , corrosive liquids 1- high capacity 2- tight shutoff 3- low cost 4- quick operation. 1- high torque for actuation. 2- cavitation at low pressure drop. 3- seat wear. 1- lubricated 2- non lubricated 3- multi port Ductile iron , iron Carbon steel, nickel, Stainless steel, plastic Ductile iron , iron Carbon steel, nickel, Stainless steel, plastic 1- body material 2- plug material 3- operating pressure. 4- operating temperature. 5- port arrangement, if multiport . 6- lubricant, if lubricated valve Plug Valve
- 28. 28 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Multi-turn valve in which closure is activated by means of A disk or plug that seals or stops the fluid on A Seat generally parallel to the line flow. 1- for throttling or flow regulation. 2- for frequent operation. 3- for positive shutoff of gases or air 4- where some resistance to flow is acceptable. 1- general service 2- slurries, 3- vapors and gases 4- liquids , corrosive liquids 1- efficient throttling with min. wire drawing or disk or seat erosion. 2- short disk travel and fewer turns to operate, saving time and wear on stem and bonnet. 3- accurate flow control. 1- high pressure drop. 2- relatively high cost. . 1- standard 2- Y pattern 3- angle 4- three - way Body Bronze, cast iron , iron Forged steel, cast steel, Stainless steel, plastics 1- install so pressure is under disk, except in high temperature steam Service. 2- lubricate on strict schedule. 3- flush foreign matter off seat by opening valve slightly. 4- correct packing leaks immediately by tightening the packing nuts. 1- type of end connection. 2- type of disk. 3- type of seat. 4- type of stem assembly. 5- type of bonnet assembly. 6- type of stem packing 7- operating pressure. 8- operating temperature. Trim Various Globe Valve
- 29. 29 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Quarter-turn valve in which a drilled ball rotates between resilient seats, allowing straight- through flow in the open position and shutting off flow when the ball, is rotated 90° and blocks the flow passage. 1- for on-off , non throttling service. 2- where quick opening is required. 3- for minimum resistance to flow is needed. 4- for moderate temp. requirements. 1- general service 2- slurries, 3- high temperatures. 1- high capacity 2- tight shutoff 3- low cost 4- compact 5- low leakage. 6- no lubrication requirements. 7- low maintenance. 8- bidirectional shutoff 1- high torque for actuation. 2- poor throttling characteristics. 3- susceptible to seal wear. 4- prone to cavitation. . 1- top entry, split body or end entry. 2- three-way, 3- full- ported. 4- reduced port. Body Bronze, cast& ductile iron, brass, aluminum, titanium stainless steel, and plastics 1- allow space for operation of long Handle 1- body material 2- seat material 3- type of port in ball. 4- operating pressure. 5- operating temperature. 6- full or reduced port. 7- top enter or side entry. Trim TFE, filled TFE, nylon Ball Valve
- 30. 30 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Quarter-turn valve that controls flow by means of circular disk with its port axis at right angles to the direction of flow. 1- for fully open or fully closed. 2- for frequent operation. 3- for throttling service. 4- for min. amounts of fluid trapped in line is allowed. 5- for low press. drop across valve 1- general service 2- slurries, liquids with suspended solids 3- liquids, gases. 1- light weight 2- low cost 3- compact 4- no pockets 5-highcapacity. 6- self- cleaning 7- straight – through flow 8- low maintenance. 9- minimum number of moving parts. 1- high torque for actuation. 2- limited pressure drop capability. 3- prone to cavitation. . 1- wafer, lug wafer. 2- flanged, screwed, 3- fully- lined. 4- high- performance. Body iron , ductile iron, bronze carbon steel , stainless steel, 1- may be operated by lever, hand wheel, or chain 2- allow sufficient space for operation of handle if lever operated. 3- valves should remain in closed position during all handling and installation operations. 1- type of body 2- type of seat 3- body material 4- seat material 5- disk material. 6- operating pressure. 7- operating temperature. 8- type of actuation.Trim all metals, elastomer coating such as TFE, neoprene Seat TFE, filled TFE, nylon Butterfly Valve
- 31. 31 Valves Classification Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Multi-turn valve that effects closure by means of a flexible diaphragm attached to a compressor . when compressor is lowered by the valve stem, the diaphragm seals and cuts off flow 1- for fully open or fully closed. 2- for throttling service. 3- for service with low operating pressure. 1- corrosive fluids, 2- sticky and/or viscous materials 3- fibrous slurries, sludge, 4- foods, and pharmaceuticals. 1- low cost 2- no packing glands. 3- no possibility of stem leakage. 4- immune to problems of clogging, corroding, or gumming of media 1- diaphragm subject to wear 2- high torque under live- line closure. 1- weir type and 2- straight- through type. metallic, solid plastic, lined- wide variety of each. 1- lubricate on regular schedule. 2- do not use bars, wrenches, or cheaters to close 1- body material 2- diaphragm material 3- end connections. 4- type of stem assembly. 5- type of bonnet assembly. 6- type of operation. 7- operating pressure. 8- operating temperature. Diaphragm Valve
- 32. Definition Recommended Application Advantages Disadvantages Variations Materials Special installation and, maintenance instructions Ordering specifications Multi-turn valve that effects closure by means of one or more flexible elements, such as diaphragms or rubber tubes ,that can be passed together to cut off flow. 1- for on-off service. 2- for throttling service. 3- for moderate temperatures. 4- where pressure drop through valve is low. 5- for services requiring low maintenance 1- slurries, mining slurries, 2- liquids with large amounts of suspended solids, 3- systems that covey solids, 4- foods, and pharmaceuticals. 1- low cost 2- simple design. 3- low maintenance. 4- no internal obstruction or Pockets to cause clogging. 5- non corrosive and abrasion- resistant 1- limited vacuum application 2- difficult to size. 1- exposed sleeve or body, 2- encased metallic sleeve or body Rubber, white rubber Hypalon, neoprene, whit neoprene Bunna-n, Bunna-s Viton-a, silicon, TFE 1- large sizes may require supports above or below the line if pipe supports are inadequate. 1- sleeve material 2- exposed or encased sleeve 3- operating pressure 4- operating temperature 32 Valves Classification Pinch Valve
- 33. Definition Recommended Application Advantages Variations Materials Special installation and, maintenance instructions Ordering specifications a relief valve is a self actuated valve designed to provide accurate automatic pressure regulation. for non- compressible fluid service and opens slowly as pressure increases, regulating the operating pressure. safety valve opens quickly with a pop action to relieve excessive pressure caused by gases or compressible fluids. where a predetermined pressure range is required 1- hot water 2- steam 3- gases 4- vapor 1- inexpensive 2- no auxiliary power required for operation 1- safety, safety relief 2- diaphragm construction for valves used in corrosive service. body cast iron ,carbon steel bronze, brass, TFE -lined stainless steel. 1- should be installed in accordance with provisions of ASME unfired pressure vessel code. 2- should be installed in readily accessible areas for inspection and maintenance 1- body material 2- seat material 3- operating pressure. 4- operating temperature. trim various 33 Valves Classification Relief Valve
- 34. Definition Recommended Application Advantages Variations Materials Special installation and, maintenance instructions Designed to heck reversal flow. Fluid flow in the desired direction open the valve, reversal of flow closes it 1- Swing check 2- Lift check 3- Ball Check Swing 1- where minimum resistance to flow is needed. 2- infrequent direction change . Lift 1- frequent direction change . Swing low velocity liquid service. Lift steam, air, gas, water, Vapor lines with high flow velocities Swing turbulence and pressure Within valve are very low. Lift 1- min. Travel of disk for full open position. 2- quick acting Swing tilting-disk check valve. Lift 1- three body patterns: angle, vertical, horizontal. 2- ball , piston check, spring- loaded check, stop check. Body Cast iron ,all iron, bronze, brass, TFE - lined Stainless steel, forged steel Swing 1- in vertical lines, pressure should Always be under seat. 2- if valve fails to seal, check seating surfaces. Lift 1- line pressure should be under seat. 2- if back flow leaks, check disk And seat.Trim Various 34 Valves Classification Check Valve
- 35. 35 Valves Classification Block Valves Gate Valve Ball Valve Plug Valve
- 36. 36 Valves Classification Throttle Valves Globe Valve Butterfly Valve Diaphragm Valve Needle Valve
- 38. 38 Valves Classification Pressure Control Valves Pressure Reducing V/V Relief V/V Safety V/V
- 40. 40 Valves on P&ID The general valve symbol, the "bow tie", may be used to indicate the body of a control valve or a hand-operated valve.
- 41. 41 Valves on P&ID The symbol for safety or relief valves consists of an angle valve combined with a spring.
- 42. 42 Valve Actuator An actuator is the part of a valve system that operates the valve. Manual Electric Motor Electric Solenoid Pneumatic Hydraulic
- 43. 43 Valves The End Of Session Any Questions?
Editor's Notes
- Used To 1- Start Or Stop The Flow Of The Medium Through The Process. 2- Hand-operated And Can Be Automated With The Addition Of An Actuator. 3- Pressure-relief Valves Are Self-actuated On-off Valves That Open Only When A Preset Pressure Is Surpassed. 4- Such Valves Are Divided Into Two Families: 4-1- Relief Valves Are Used To Guard Against Over Pressurization Of A Liquid Service And, 4-2- safety Valves. Are Applied In Gas Applications Where Over Pressurization Of The System Presents A Safety Or Process Hazard And Must
- 1- Allow The Fluid To Flow Only In The Desired Direction. 2- Used To Prevent Backflow Of Fluid, Which Could Damage Equipment "Or Upset The Process. Such Valves Are Especially Useful In Protecting A Pump In Liquid Applications Or A Compressor In Gas Applications From Backflow When The Pump Or Compressor Is Shut Down
- -Regulate the flow, temperature, or pressure of the service. - Can move to any position within the stroke of the valve and hold that position, including the full-open or full-closed positions. Therefore, they can act as on-off valves also. -Hand-operated and can be equipped with actuators . automatic control valves, sometimes referred to simply as control valves, -To achieve automatic control, these valves are always equipped with actuators. Actuators are designed to receive A command signal and convert it into an specific valve position using an outside power source (air, electric, or hydraulic), which matches the performance needed for that specific moment.
- Designed For The Majority Of Applications: - Lower-pressure Ratings (16 To 100 Bar.) - Moderate-temperature Ratings -50 To 650°f (-46 To 343°c), - Non Corrosive Fluids, And Common Pressure Drops That Do Not Result In Cavitation Or Flashing. - Have Some Degree Of Interchangeability
- - Designed For A Single Application That Is Outside Normal Process Applications. - Such Valves Usually Handle A Demanding Temperature, High Pressure, Or A Corrosive Medium.
- - Valves Equipped With Special Features To Handle Volatile Applications, Such As High Pressure Drops That Result In Severe Cavitations, Flashing, Choking, Or High Noise Levels - Such Valves May Have Highly Engineered Trims In Globe-style Valves, Or Special Disks Or Balls In Rotary Valves To Either Minimize Or Prevent The Effects Of The Application.
- -The Term Closure Element Is Used To Describe Any Internal Valve Device That Is Used To Open, Close, Or Regulate The Flow.
- - Usually Smaller In Size And Weight Less Than Comparable Linear Valves, Size For Size. Application Wise, They Are Limited To Certain Pressure Drops And Are Prone To Cavitation And Flashing Problems.
- 1- Most Valves Are Designed To Restrict The Flow To Some Extent By Allowing The Flow Passageway Or Area Of The Closure Element To Be Smaller Than The Inside Diameter Of The Pipeline. 2- Some Gate And Ball Valves Can Be Designed So That Internal Flow Passageways Are Large Enough To Pass Flow Without A Significant Restriction. 3- Full-port Valves Also Allow For The Use Of A Pig In The Pipeline.
- 1- Closure Elements Restrict The Flow. 2- The Flow Area Of That Port Of The Closure Element Is Less Than The Area Of The Inside Diameter Of The Pipeline. 3- This Restriction Allows The Valve To Take A Pressure Drop As Flow Moves Through The Closure Element, Allowing A Partial Pressure Recovery After The Flow Moves Past The Restriction. 4- The Primary Purpose Of Reduced-port Valves Is To Control The Flow Through Reduced Flow Or Through Throttling, Which Is Defined As Regulating The Closure Element To Provide Varying Levels Of Flow At A Certain Opening Of The Valve.