Control valves and specifications summation of category and design -conversion-gate01

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Control Valve

Control Valve plays a very important part in industries.

It controls and distributes pressure, flow, level, temperature etc.

Control valve may be considered the MUSCLE of automatic control.

VALVES

Valve:Any Device for closing or

modifying the passage through a pipe, outlet, inlet

or likely to stop, allow or control the flow of a

media.

Valve cost is upto 20 to 30% of the piping cost for a plant, depending on the process; and the cost of a given type and size of valve can vary 100%, depending on its construction.

Thus the selection of valves is extremely important to the economics, as well as operation, of process plants.

The size of a valve is mainly determined by the size of its ends, which connect to the pipe.

CLASSIFICATION OF VALVES

G AT E V ALVE

B A LL V A LV E

P LU G V ALVE

P IS T O N VA LVE

D IA PH R A G M V A LVE

B U T T E R FLY VA LVE

P IN C H V ALVE

IS O L A T IO N

G LO B E VA LV E

N E E D LE V ALVE

BU T T ER FLY VA LVE

D IA P H R A G M V ALVE

PIS T O N V A LVE

BA LL VA LV E

PLU G V ALVE

PIN C H V A LVE

R E G U L A T IO N

SW IN G C H E C K V ALVE

LIFT C H EC K V ALVE

C H E C K V A LV E

N O N R E T U R N

M U LT I P O R T V ALVES

FLU S H BO T TO M VA LV ES

FLO A T V A LV E S

FO O T V A LVE S

LIN E BL IN D VA LV ES

KN IFE G A T E V ALV E S

S P E C IA L P U R P O S E

B A S E D O N F U N C T IO N S

S C R E W ED E N D S

S O C K ET W E LD E N D S

F LA N G ED E N D S

B U T T W E LD E N D S

W A F E R T Y P E E N D S

B a se d o n e n d con ne c tio ns

C A ST IR O N

D U C T ILE IR O N

B R O N ZE

G U N M E T AL

C A R B O N S T E EL

S T A IN LE S S S T E E L

A LLO Y C A R B O N S T E EL

P O LY P R O P Y LE N E

G LA S S

B A S E D O N C O N S T R U C T IO N M A T E R IA L

in B a ll a n d B u tte rf ly va lv es

H a n d le ver

in G a te ,G lo be an d D ia p hra gm va lves

H a n d w h e e l

C h a in

G e ar

E le c tric P n e um a tic

H yd ra u lic

P o w e red

S o len o id

fo r sm a ll P lu g va lves

W re n ch

B a se d on op e ra to rs

VALVES:Basic Parts:

1.Body2.Bonnet3.Stem4.Disc5.Seat6.Port7.Seal (includes Gasket, Metal Bellows)

Body:--The Body & Bonnet houses the stem.

-- Selection of the material to fabricate the interior of the wall body is important if the valve is used for the process of chemical.

--Some Valves may be obtained with the entire interior of the body lined with corrosion resistant material.

Bonnet: The Bonnet is a part which is attached with the body of the valve. The Bonnet is classified on the type of attachment as Bolted, Bellow, Sealed, Screwed-on, Welded, Union, Pressure Sealed etc.,

Stem: The Stem moves the disc. In some valves the fluid under pressure does the work of the stem.

--There are two categories of screwed stem.

(a) Rising Stem: Hand wheel can either rise with the stem, or stem

can rise through the stationary hand wheel.

(b) Non-Rising Stem: The Hand Wheel and the stem are in the same

position weather the valve is opened or closed. In this case, the screw is inside the Bonnet

and in contact with the fluid.

DISC, SEAT & PORT:

The part directly affecting the flow is termed as Disc regardless of its shape.

The Non-moving part the body bears is termed as seat.

The port is the maximum internal opening for flow.

SEAL:BETWEEN STEM AND BONNET:

-- Gasket is used in between a bolted bonnet and valve body.

-- Metal Bellows where high vaccum or corrosive, flammable fluids are to be handled.

-- Flanged Valves use gasket to seal against the line flanges.

-- Butterfly Valves may extend the resilient seat to also serves as line gaskets .

Based on the shape of the port these valves can be classified into,

(1)Regular pattern: They have plug ports generally

rectangular in section and have area substantially equal to full bore of the pipe.

(2) Short pattern: Face to face dimensions corresponding to

gate valves. (3) Venturi pattern: They have reduced port area.Thus

producing a venturi effect to restore a large percentage of velocity head loss through the valve and produce a resultant total pressure drop of relatively low order.

_ Operator: This is a device, which opens or closes a valve. Different devices are available.

MANUAL OPERATORS (1) Hand lever: It is used to actuate the stems of

small butterfly, ball, plug valves and cocks. Wrench operation is used for cocks and small plug valves.

(2) Hand Wheel: It is the most common means of rotating the stem on the majority of popular smaller valves such as gate, globe and diaphragm. Hammer blow or impact hand wheels that may be substituted for normal hand wheels, if easier operation is needed but where gearing is unnecessary offer additional operating torque for gate and globe valves.

(3) Chain: It is used where a hand wheel would be out of reach.

The stem is fitted with a chain wheel or wrench (for lever operated valves) and loop of the chain is brought within one meter of working floor level.

(4)Gear : These are used to reduce the operating torque. For manual operation, it consists of a hand wheel operated gear train actuating the valve stem.

As a thumb rule, gear operators should be considered for valves of 350 mm NB and larger upto 300#, 200 mm NB and larger upto 600#, 150 mm NB and larger upto 1500# and 100 mm NB and larger for higher ratings.

§ Pneumatic and Hydraulic: These may be used where flammable vapour is likely to be present. They are of following forms:

§ Cylinder with double acting piston driven by air, water, oil or other liquid, which usually actuates the stem directly.

§ Air motor, which actuates the stem through gearing. These motors are commonly piston and cylinder radial type.

§ A double acting vane with limited rotary movement in a sector casing, actuating the stem directly.

POWERED OPERATORS:

Electric Geared Motor: Geared Motor moves the valve stem. This is useful for operating large valves in remote areas.

Solenoid: These can be used for fast acting check valves, and with on/off valves in light-duty instrumentation applications.

VALVES IN DETAIL:

Gate valve: They function as block valves.

75% of all valves in process industries are gate valves.

Gate valves are not suitable to throttle flow because it will pass maximum flow when it is partially open.

The end flanges can be integrally cast into the body.(ref:ANSI B16.5 for flanged connections).

Also for welded connections(ref:ANSI B16.11 for weld/screw connections).

There are two types of port designs

(1) Full port design: The net area of the bore through the seat

is as nearly as equal to the pipe size.

(2) Reduced port design:The port diameter is normally one size

less than the size of the pipe.

Gate valveFlow in

Flow out

GATE VALVEPRESSURE-SEAL BONNETGATE VALVE

BOLTED BONNETFLEX WEDGE

BALL VALVE:

Ball valves function as both block valves and flow regulating(special design) valves.

Quarter turn positive shut off valves.

Suited for conditions where quick on-off and/or bubble tight shut off is required.

Soft seats are usually used only for low temperature services.

Metal seated ball valves are used for high temperature services.

Soft seats are not normally used for throttling because of erosion or distortion/displacement caused by fluid.

The Pressure – Temperature ratings are established based on the seating material.

Offers minimum resistance to flow.Advantages:Easy Operation.Low torque.Low Pressure Drop.Economical.Excellent Sealing.( Used in Vacuum Services)

-- Two designs are available.

(1) Regular port design: The port diameter will be smaller than

the pipe inside diameter. Normally the port diameter is one size less than the pipe diameter.

(2) Full port Design: The port diameter of the valve will be

the same as that of the pipe inside diameter.

PLUG VALVE:

Plug valves are quarter turn positive shut off valves.

Well suited for quick ON/OFF, AND/OR bubble tight shut off.

Not normally used for throttling, because soft seats are subjected to erosion.

Lesser resultant total pressure drop across the valve.

In certain designs,a low friction Poly Tetra Fluro Ethylene (PTFE) is impregnated on the surface structure of the valve plug.

Based on sealing,

Lubricated metal seated plug valves:

The lubrication of the seating surfaces is by means of lubricant,which is fed into the operating surfaces.

Cross Section of a Plug Valve:

ADVANTAGES OF PLUG VALVE:

Used in Oil & Gas Industries. Fly Ash Applications. Plug & Body Seating Surfaces which are lapped &

matched aren’t exposed to the line fluid, which reduce the corrosion and Erosion loses.

Fire Safety. Reduced torque. Online Maintenance.

Butterfly valve:

-- They are quarter turn positive shut off valve.-- Seats are made of PTFE with certain

reinforcement.-- Valves up to 12” are operated with lever.-- Higher diameter valves are provided with gear

unit and hand wheel.-- These valves are wear resistant.-- Elastomers have higher life expectancy than conventional metallic seated valves when used in high density mineral slurry services.-- Generally used for line sizes >8”.

Cross Sectional Top View

WRENCH CONTROLED WAFER TYPE BUTTERFLY

VALVE

HAND WHEEL CONTROLED

BUTTERFLY VALVES

GLOBE VALVE:

-- Globe valves are mainly used to throttle the fluid flow.-- Smaller sizes are hand controlled.

-- Application of larger size valves are limited to bypass control valve stations.

-- Provide relatively tight shut off.

-- Valve patterns involve change in flow directions.-- The discs of globe valves shall be flat-faced type, plug type,ball type,needle type,port type.

-- Commonly used for pipe sizes up to 8”-- High pressure drop across valve.

CHECK VALVE:

-- Check valves prevent flow reversal.

-- Typical check valve applications are in pump and compressor discharge piping.

-- Valves with discs provide lower resistance to flow of working fluid than those that contain balls or pistons.

-- The later are often used where there is an angular change in flow stream.

-- Ball and lift check valves are used for sizes 2” and smaller.

-- Swing check and Plate check valves are used for higher pipe sizes.

-- Major types are as below.

SWING CHECK VALVES:

--The disc swings freely in the form of an arc.

--Valve is kept open by the flow and disc seating is accomplished by gravity and/or flow reversal.

-- When used in vertical lines the flow should be upwards only.

SWING CHECK VALVE-WORKING:

LIFT CHECK VALVES:

-- Basic types are piston lift check valve,Ball lift check valve etc.,

-- Used for sizes ½” to 2”.-- Reverse flow forces piston or ball against

seat.-- Used to control vertical flow.

THE PRESSURE RELIEF VALVE

Drawing and simulation of a direct operating pressure relief valve: left: valve closed; middle: symbol of a direct operating pressure relief valve according to ISO 1219; right: simulation of an operating pressure relief valve Description: The pressure relief valve is mounted at the pressure side of the hydraulic pump. It's task is to limit the pressure in the system on an acceptable value. In fact a pressure relief valve has the same construction as a spring operated check valve. When the system gets overloaded the pressure relief valve will open and the pump flow will be leaded directly into the hydraulic reservoir. The pressure in the system remains on the value determined by the spring on the pressure relief valve! In the pressure relief valve the pressure (=energy) will be converted into heat.For that reason longtime operation of the pressure relief valve should be avoided.

Closed position

Open position

DIAPHRAGM VALVE:

-- These valves are used for low pressure corrosive services as shut off valve.

-- These can also be used as control valves.-- Here the diaphragm moves up and down to

operate the valve.-- The major parts of diaphragm valves are,

1.Body2.Diaphragm3.Bonnet4.Stem5.Stem bushing6.Compressor7.Hand wheel8.Bonnet bolting.

CONTROL VALVES & PRESSURE REGULATORS:

-- Control valves automatically regulates temperature, pressure,level and flow rate for any process variables.

-- The control valve is usually chosen to be smaller than line size to avoid throttling and consequent rapid wear of the seat.

-- Globe pattern valves are normally used for control and their ends are usually flanged for ease of maintenance.The disc is moved by hydraulic,pneumatic or electrical operators.

-- Control valves of globe type which adjusts downstream pressure of liquid or gas to a set pressure is called as Pressure regulators.

Fig shows how a control valve can be used to control the rate of flow in a line.

--Here flow rate is related to the pressure drop across the sensing element.

--The controller receives the pressure signals,compares them with the

pressure drop for the desired flow and thus if the actual flow is different ,it

adjusts the control valve to increase or decrease the flow.

VALVE SELECTION PROCESS:

-- The steps that follow provide a general procedure for selecting valve components,

1. Determine operation-on/off, regulating, special purpose.

2. Determine type of conveyed fluid-liquid,gas,slurry or powder.

3. Determine nature of fluid: Neutral services: Oil,Drinking water, Nitrogen, Gas,

Air. Corrosive service: Acid,Alkaline. Hygienic services: Food,Drugs. Slurry: Suspension of solid particles in the fluid media.

4.Pressure and temperature of conveyed fluid. 5.Method of operating stem: consider closing

time. 6.Cost.

7.Availability.8.Installation problems:Such as welding valves

into lines.

Hydro tests Pneumatic Tests Fugitive Emission & Helium Leak Tests Cryogenic Tests Fire Tests Hot & Cold Cyclic Tests Seismic Tests Natural Frequency Tests Static Load Simulation Pipe End Reaction Tests

TESTS CONDUCTED ON VALVES:

Valve afterCryogenic

Test

Fire Test

Cryogenic Test Facility

TESTING FACILITIES:

42” Trunnion-mounted Ball Valve undergoing

Hydro test

TERMS USED FOR VALVES SPECIFICATION:

1.Pressure-Temperature ratings: It is the maximum allowable sustained non-

shock pressure at the corresponding tabulated temperatureReference standards: ANSI B 16.34 & ANSI B 16.5.

2.Class: As per American standard,

Class 150# Class 300# Class 600#Class 900#Class 1500# Class 2500#Class 4500#

Material Standards- ASTM (America Society for Testing and Materials)

Dimensional Standards-ANSI (American National Standards Institute)

Adapted by ASME (American Society for Mechanical Engineers) The American Petroleum Institute (API) Standards for Some

Commonly used Valves are as follows: API 6D – Pipe Line Valves, End Closures, Connectors and Swivels API 6F – Recommended Practice for Fire Test valves API 593 – Ductile Iron Plug Valves – Flanged Ends API 598 – Valves Inspection and Test API 600 – Steel Gate Valves API 602 – Compact Design Carbon Steel Gate Valves API 604 – Ductile Iron Gate Valves – Flanged Ends API 607 – Fire Test for Soft Seated Ball Valves

The American Iron and Steel Institute (AISI), Standardsfor Some Commonly used Valves are as follows:

American Welding Society (AWS) American Water Works Association (AWWA)These Standards refer to the piping elements required for low

pressure water services. These are less stringent than other standards. Valves, Flanges etc.,

required for larger diameter water pipe lines are covered under this standard and are referred rarely by the piping Engineers.

C – 500 : Gate Valves for Water and sewage systemC – 510 : Cast Iron Sluice Gate ValvesC – 504 : Rubber Seated Butterfly ValvesC – 507 : Ball Valves 6” to 48”C – 508 : Swing Check Valves 2” to 24”C – 509 : Resilient Seated Gate Valves for Water and sewage

The Manufacturers Standardization Society of Valves and Fitting Industry – Standard Practices (MSS – SP):

In addition to the above standards and material codes, there are standard practices followed by the manufacturers and are widely used.The most Common MSS-SP standards referred for Valves are as follows:

MSS – SP – 42 : Class 150 corrosion resistant gate, globe and check valvesMSS – SP – 61 : Pressure testing of valves MSS – SP – 67 : Butterfly ValvesMSS – SP – 68 : High Pressure off seat butterfly valves MSS – SP – 70 : Cast iron gate valvesMSS – SP – 71 : Cast iron check valvesMSS – SP – 72 : Ball Valves MSS – SP – 78 : Cast iron plug valvesMSS – SP – 80 : Bronze gate, globe and check valves MSS – SP – 85 : Cast iron globe valves MSS – SP – 88 : Diaphragm valvesMSS – SP – 108 : Resilient seated eccentric CI plug valves

BRITISH STANDARDS (BS): The following are some of British Standards referred by Indian Manufacturers

for Valves: BS 970 : Steel for Forging, Bars, Rods, valves steel, etcBS 1212 : Specification for Float Operated ValvesBS 1414 : Gate Valves for Petroleum IndustryBS 1868 : Steel Check Valves for Petroleum Industry BS 1873 : Steel Globe and Check Valves for Petroleum IndustryBS 2080 : Face to Face / End to End dimensions of ValvesBS 5150 : Cast Iron Wedge and Double Disc Gate Valves for general purposesBS 5151 : Cast Iron Gate (Parallel slide) Valves for general purposesBS 5152 : Cast Iron Globe and Check Valves for general purposes BS 5153 : Cast Iron Check Valves for general purposes BS 5154 : Copper alloy Globe, Gate and Check ValvesBS 5155 : Cast Iron and Cast Steel Butterfly Valves for general purposes

BS 5156 : Diaphragm Valves for general purposesBS 5157 : Steel Gate (parallel slide) Valves for general

purposesBS 5158 : Cast Iron and Cast Steel Plug Valves for general

purposesBS 5159 : Cast Iron and Cast Steel Ball Valves for general

purposesBS 5160 : Flanged Steel Globe and Check Valves for general

purposesBS 5163 : Flanged Cast Iron Wedge Gate Valves, smaller than

2”NBBS 5353 : Specification for Plug ValvesBS 5433 : Specifications for underground stop valves for water BS 6364 : Specifications for Valves for Cryogenic servicesBS 6755 : Testing of ValvesBS 6759 : Safety Valves

INDIAN STANDARDS : Bureau of Indian Standards (BIS) Unlike American Standards, Indian Standards cover Dimensional and material

Specifications under the same Standard Number:The following are some of the commonly referred Indian standards by Piping Engineers: IS 778 : Specification for Copper Alloy Gate, Globe and Check ValvesIS 780 : Specification for Sluice Valves – 50 NB to 300 NBIS 2906 : Specification for Sluice Valves – 350 NB to 1200 NBIS 4038 : Specifications for Foot ValvesIS 5312 : Specification for Check ValvesIS 6157 : Inspection and Testing of ValveIS 10605 : Steel Globe Valves for Petroleum IndustriesIS 10611 : Steel Gate Valves for Petroleum IndustriesIS 10805 : Foot ValvesIS 11790 : Code of practice for preparation of Butt welding ends for valves, flanges and

fittingsIS 11792 : Steel Ball Valves for Petroleum IndustryIS 13095 : Butterfly Valves DIN standards of Germany and JIS standards of Japan.

ERECTION TIPS:

Gate/ Globe Stem to be erected in vertical direction to avoid the chances of leakage.

Check Valve to be erected in Horizontal and according to the flow of direction marked in the valve.

While lifting Higher size Gate valves, Integral By-pass lines should not be used for lifting purpose.

If Valves are tested with water, Valve internals to be dried by Nitrogen/ Air.

Quality needs:

ISO 9001-2000.API Spec Q1.API 6A.API 6D (Product Specification).IBR.

Types of Valves

Gate Valve

Globe Valve

Plug Valve

Butterfly Valve

Diaphragm Valve

Major Parts of a control Valve

A control valve consists of two major sub-assemblies.– A valve body sub-assembly– An actuator.

The valve body sub-assembly is the portion that actually controls the passing fluid.

It consists:– Housing – Internal trim– Bonnet

Types of Valve Bodies

Globe Styles– The most common control valve body style is

in the form of a globe.– Such a control valve body can be either single

or double-seated.– Single-seated valves, are usually employed

when tight shut-off is required.– Tight shut-off in this case usually means that

the maximum expected leakage is less than 0.01% of the maximum valve CV

Single Seated Valves

Single-seated valves usually have a top

guided construction.

It also allows a somewhat higher flow

capacity than top and bottom guided valves

for a given orifice size.

Double-seated value

A double-seated value, is generally top and bottom guided.

Leakage figure approaches 0.5% of the rated CV.

It is nearly impossible to close the two ports simultaneously

Advantage of double-seated construction lies in the reduction of required actuator forces.

Angle Valves

These Valves are single-seated.

Used for high pressure drop service.

Minimum Space required.

Cage Valves

So-called "top entry" or cage valves have the advantage of easy trim removal.

Typical top entry valve with unbalanced, single-seated trim.

The inner valve parts, often referred to as "quick change trim," can easily be removed after removing the bonnet, because of the absence of internal threads.

Rotary Types of Control Valves

Advantages– Low weight

– Simple design

– High relative CV

– More reliable

– Friction-free packing

– Low initial cost.

Rotary Types of Control Valves

Disadvantage

– Generally not suitable below 1 to 2 inches.

– Operating shaft must be designed to support a

fairly heavy side-thrust.

– Leakage problem.

Butterfly Valves

The most common type of rotary valve

used for control is the butterfly valve.

The typical application range is in sizes

from 2 inches through 36 inches or larger,

for low or moderate pressures.

Leakage 0.5% of rated CV.

Valve Bonnets

The valve bonnet or top closure is the removable upper portion of the valve body sub-assembly and is normally connected to the body by high strength bolting.

It is a pressure-carrying part and is, therefore, subject to the same design requirements as the valve housing.

Removal of the valve bonnet generally provides access to the valve trim.

Valve Bonnets

Some low-pressure valves, particularly in

sizes below 2 inches, have a threaded

bonnet connection which is more

economical than a flanged joint.

The upper portion of the bonnet contains

the valve packing.

Valve BodyBonnet

Valve Body

Valve Body

Packing Box Assembly

The purpose of the packing box assembly is to contain an elastic means for preventing the leakage of a process fluid.

Suitable adjustments should be provided for varying the compression of the packing material against the surface of the stem.

The ideal packing material should be elastic and easily de formable.


In addition, the packing should be as chemically inert as possible

Should be able to withstand high pressures and high temperatures.

Selection must be made from a variety of materials to suit the specific service conditions.


The assembly consists of a:-– Packing flange – Packing follower (Bush)– Lantern ring– A number of equally spaced packing rings.– The lantern ring provides a space for the

insertion of lubricating grease though an isolating valve.

Packing Material

Teflon (PTFE)

Graphite

Grafoil

Asbestos (Now a days it is not being used)

Teflon Cord

Graphite cord

Packing Material

To make rings

Special Tool or

With the help of a Electrician knife

How to cut and paste the rings

Inert Gas as a Packing

Another approach is to pressurize the area between the two packing with inert gas at a pressure level, slightly higher than the fluid pressure inside the valve.

In this case, the inert gas might leak into the valve, but no fluid is allowed to leak by the stem.

This packing arrangement is more reliable.Very Expensive

Teflon

The most popular valve packing material is Teflon.

Because of its excellent chemical inertness and its good lubricating properties.

Teflon can be used in solid-molded or turned form (rings).

Solid rings should be spring-loaded to provide a minimum initial pressure against the stem.

It can be used below 250°C.

Braided Asbestos

Braided asbestos is still a popular packing material (even prohibited to use).

It can be made as split rings.Which can be wrapped around the valve

stem.This type of packing usually used with mica

or graphite, particularly in high temperature service.

Grafoil

A recent addition to the list of available packing materials is Grafoil.

Grafoil is an all-graphite product that is flexible and has direction-dependent properties.

It is essentially, chemically inert, except when strong oxidizers are handled.

Valve Trim

Main Items:– Plug

– Seat Ring

– Stem

– Cage

– Guide Bushing

– Stuffing Box

Plug

Types

Types depends upon flow characteristic:

– Quick Opening

– Linear

– Parabolic or Equal Percentage

Plug / Seat

Direct Action Single Seated

Reverse Action Single Seated

Direct Action Double-Seated

Reverse Action Double-Seated

Plug

Contoured Plug

– Top Guided

– Shape of the plug• Flat Quick Opening

• A bit Conical Linear

• Tapered but not conical Equal Percentage

Plug Linear

Plug Equal Percentage

Plug Quick Opening

Different Shapes of Plugs

Characteristics of Different Plugs

Valve Opening 30 %

– Quick Opening CV 62

– Linear CV 30

– Equal % CV 8

– V-Port CV 6


Valve Opening 70 %


– Linear CV 70

– Equal % CV 33

– V-Port CV 30


Valve Opening 100 %


– Linear CV 100

– Equal % CV 100

– V-Port CV 100

Valve Body

Plug & Cage

Complete Control Valve

Actuator

Diaphragm

Spring

Yoke

Indicator

Coupling Assembly


Stem

Bush

Check Nut of yoke

Packing Box

Bonnet

Body


Plug

Seat Ring

Cage

Gaskets

Bottom Guide

Plug

Types– Contoured Plug

• Single Port• Double Port• Different Shapes

– V- Port • Single Port• Double Port• Multi-v-port plug

– Reduces noise

Contoured Plug

Contoured Plug

Contoured Plug

Plug

Disc– Single Port

– Double Port

Mixed Type– (Used to reduced the dynamic unbalance fluid

forces)

Balanced Plug

Disc Type Plugs

Butterfly Disc

Butterfly

– Very simple construction

– High Capacity with Low Pressure

– Leakage Class III

Butterfly Valve

Butterfly

V Port Plug

Ball Valve

– These Valves offer the advantages

• Highest Flow Capacity

• Low Operating Force

• Tight Shut Off

Ball Valve

Ball Valve

Ball Valve

Plug

Material– CS Carbon Steel– SS Stainless Steel

• 410 SS• 440-C SS• 316• 304• 17-4 PH

– To improve Hardness• Stellite

Seat Ring

Just like a Washer

Same material as Plug

With Threads / Without Threads

Alignment

– Face to Face

Stellite

Seat Ring

Alignment

Alignment

Cage

A bit less hard materialBut according to the requirement of processGuides the PlugReduces the noise (10 to 15 db)Quick OpeningLinearEqual PercentageSlotted Cage

Quick Opening

Linear

Equal Percentage

Different shape of Cages



Sealing Arrangement

2nd Major leakage between plug and cage

Back up Rings

Material

– Graphite

• Very Careful Brittle

– Teflon (PTFE)

Gaskets

Seat Ring GasketUpper CageBody GasketMaterial

– Graphite / Grafoil– Asbestos– Neoprene

Actuators

Diaphragm

Piston

Direct Action

Reverse Action

Diaphragm

Direct Action

Reverse Action

Flexible material– Rubber

– Neoprene

– With Enforced material Fiberglass, cotton,

nylon

Direct Action Diaphragm

Reverse Action

Diaphragm Size of actuator depends upon

– Valve size– Process pressures

Large size– Un-necessary expensive– Delay

Under size– Might be impossible to open or close the valve 100 %.

Diaphragm casings Diaphragm Plate O rings

Piston Actuators

Piston Actuator Cylinder Actuator

For high pressure

Large diameter of pipe line

Single Acting with spring

Double acting

Range Spring

Diaphragm size

Bench Set

– 3 to 15 PSI

– 6 to 21 PSI

– 6 to 30 PSI

Yoke

Linkage between actuator and valve bodyUsually self aligned but needed very

carefully to install.Tag, Name plate

– All data about actuator– Supply Pressure – Bench set– Air to open or air to close

Yoke

Working of Control Valve

Simple ValveWithout PositionerBench Set 3 to 15 PSINo air supply neededOnly I/P or controller out put 3 to 15 PSI

will operate the Valve.Direct Action

Control Valve without Positioner

Positioner

Main function

– Just like a controller

– To cover bench set

– Quick Response

Positioner

In put– 3 to 15 PSI

Out Put– 3 to 15 PSI

– 6 to 21 PSI

– 6 to 30 PSI

– Depends upon Bench Set of the valve

Application of Positioner

Common Applications– To increase the control valve speed.– To operate spring-less actuators– Split range operation – Reverse action– To change the control valve flow characteristics– Nature of flow medium

• For jam type process

Application of Positioner

Limitations

– Adding in the loop a controlling device

• Loop must have minimum devices

– Expensive

– Can be achieved better results with the help of

– Volume booster

– Pressure booster

Types of Positioners

Side mounted

Top mounted

Double acting Positioner

Electronic

Control Valve With Positioner

Valve with Positioner

Valve With Positioner

Positioner

Control Valve with Positioner

Control Valve with Positioner

Cams

Linear

Equal Percentage

Quick Opening

Cams

Cams

Cams

Cams

Volume Booster / Pressure Booster

Volume booster increases volume of air for diaphragm

To increase the speed of operationAlmost a essential component of a vent

valvePressure booster also used for increasing

the speed of control valves by increasing the pressure.

Flashing / Cavitations

Flashing– Just like a sand blasting– Flashing liquid contains vapours– Vapours acts like a sand and liquid acts like a

carrierCavitation

– Two stage phenomenon– 1st stage Formation of voids or cavitations

with the liquid system

Flashing / Cavitations

2nd stage Collapse or implosion of

the cavitaion back to the liquid

Result Cavitaion Damage of trim

material

of valves.

Flashing

Cavitation

Complete Valve

To Inspect Trim Material

Marking the side of yoke with bonnetMarking the side of bonnet with bodyNoting ThreadsValve is under Bench Set PressureTo release the bench spring pressure, apply

signal to open the valve– Even the valve is faulty and not in operation

condition.

Yoke / Bonnet Marking


Loose coupling / Connector

The lift of valve should be not more than 10%.

After disconnecting stem & coupling, Remove Check nut of yoke

Remove Valve Actuator etc.

Loose bonnet bolts


Inspect every trim material especially

Seat Ring

Plug

Gaskets

Body erosions

Bonnet erosions


Any crackNot leave any thing abnormal.Replace Glands

– If OK then insert one or more rings if possibleOuter surface of seat and plug are usually

made harden. – If machining is required then be careful about

the depth of cut.


If cage is being used then

Check its sealing gasket

Back up rings

If not original available then locally fabricated should match the material with process.

Sealing Gasket / Back up Ring

Tightening Procedure

To Dismantle Diaphragm

Marking

Spring Force

Bench Set

Usually Force becomes minimum, while loosing the nut / bolts

Four long bolts



Installation

Control Valve With Two H.Wheels

Dryer

Control Valve

SupplyNRV

Capacity Tank

PositionerSOV

Regulator

3 to 15 PSI Signal

110 V DCVolume Booster

Control Valve Loop

SOV

Energized De-Energized

Supply Out Put

Bleed

1 2

3

1 2

3

Precautions

In case of Electric device such as

– SOV

– Must have Explosion proof class.

– When working at terminal or in J.B.

– It is in open condition, one must be more

careful, because Explosion proof system is

violated.

Control Valve Loop

SupplyNRV

Capacity Tank

PositionerRegulator

3 to 15 PSI Signal

Lock Up Relay

Setting Procedure of Lock Up Device

To provide Regulated supply.Monitor the supply at out put gaugeNo leakage should other portsDecrease the set pressure, Port should

change its path.E Port pressure gauge should indicate the

above signal pressure.Repeat the same procedure for other ports

also.

Checking & calibrating Procedure of Lock Up Device

Supply

Signal A

C

B

D

E F

Control Valve Loop

Valve Loop

Hand Jack / Hand Wheels

Top Mounted

Side Mounted

Two Hand Jacks

Hand Jacks can be used as Stopper

Must have opened 5%, 10% or should not be closed more than 90%.

Auto/Manual Procedure of Control Valves (A)

Auto to Hand Jack – Check the hand jack indicator is in “neutral”

position.

– Move the hand jack clockwise / anti-clockwise to engage the lever mechanism.

– Close instrument air supply of control valve.

– Move the hand wheel clock wise or anti-clock wise to open or close the valve.

Auto/Manual Procedure of Control Valves (A)

Hand Jack to Auto

Inform control room crew to give the signal of

controller according to the valve opening.

Open instrument air supply of control valve.

Move the hand wheel to “neutral” position slowly.

Check pressure gauge indication of signal to the

diaphragm for further confirmation.

Side Mounted Hand Jack

Side Mounted Hand Jack

Auto/Manual Procedure of Control Valves (B)

Auto to Hand Jack Move the handwheel clockwise to engage

valve stem with handwheel by inserting pin in it.

Open instrument air by pass valve of pistonMove the handwheel clockwise / anti-

clockwise to open / close the valve respectively.

Always check the heath of inserting pin.


Hand Jack To AutoClose instrument air signal by pass valve.Inform Control room crew to give out put

signal of controller according to the valve opening.

Remove the pin and disengage the stem and hand wheel.

Move the handwheel to full anti clock wise position.



Auto/Manual Procedure of Control Valves (C)

Auto/Manual Procedure of Control Valves (C)


Louver

Different Type of Hand Wheels

Different Type of Hand Wheels

Leakage

Between:

– Seat & Plug

– Cage & Plug

– Packing Material (Glands)

– Bonnet

– Flanges

To Check Valve is Passing

1. Down stream isolating valve

2. Body Temperature

3. Valve Opening Reduces 50% 35%

4. Abnormal Sound

Valve Sizing

PGQCv

Liquid

)2(1360 PPTfGQCv

Gases

PwCv

3.63

Steam & Vapours

Valve Sizing

Where– Cv = Flow Rate – liquid (gpm)

- gases (scfh)- vapours (lb/h)

– G = Specific gravity of the process. – Tf = Flowing temperature in degree F°– P = Process drop in PSI (P1-P2)– P1 = Upstream Pressure at valve inlet in

PSI absolute– P2 = Downstream Pressure at valve

discharge in PSI absolute– = Down stream specific volume in cubic feet per

pound

Jacketed Valve

Globe Style

V-PortDouble Seated¾” to 24”General Service

Leakage 0.5% of Rated CV

Small Actuator Force Required than Single Seat

Globe Style

Single Seated

Single Seated

– Top and Bottom Guided

1 – 16”

General Service


Single Seated

Single Seated

Single Seated

Top Guided

½ - 16” (30” Max)

General Service


Single Seated-Top Guided

Cage Design

1 – 12”

Better Plug Guiding

More Stable Throttling

Quick Change Trim

Cage

Angle

½ - 12”

Y Style

¾ -14”

Used more frequently in On – Off Service

Corrosive service


Direct Action Double Seated

Reverse Action Double Seated

Reverse Action Single Seated

Double Seated – Top & Bottom Guided

Single Seated -Top Guided

Single Seated

Linear Valve

Direct Action

Reverse Action

3 Way Valve

THANK YOU….

Linkedin: mohammad amin saleh ahmadi

Technology

Control valves and specifications summation of category and design -conversion-gate01