valve presentasion

26
FLANGE VALVE GENERAL Pressure Relief Devices OPERATOR TYPE

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Describe about Valve

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Page 1: Valve Presentasion

FLANGE

VALVE GENERAL

Pressure Relief

Devices

OPERATOR

TYPE

Page 2: Valve Presentasion

General

A Valve is a device that regulates, directs or controls the flow of a fluid by opening, closing or partially obstructing various passageways. In process operations, fluids and their movement and transfer from place to place, plays a large part in the process. Fluids are contained in various types of vessels and are transported in pipelines. In order to Start or Stop fluid flow, to Control flow and to Prevent Back-flow, various types of valves are installed in the piping. To prevent over-pressure in piping and vessels, we use Safety Relief valves and, to isolate equipment for maintenance etc., Block valves are installed.

As previously stated, valves are used for the following purposes: 1. To start and stop flow of fluids 2. To regulate, throttle and control fluid flow or pressure 3. To prevent back-flow 4. To relieve excess pressure / vacuum

Page 3: Valve Presentasion

General

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Type of Liquid

Liquid

Gas

Erosive

Corrosive

Flow Consideration

On-Off or Throttling

Prevent Backflow

Concern for Pressure drop

Velocity Pressure

Temperature

Operating Conditions

Frequency of Operation

Accessibility

Overall space available

Manual or Automated control

Need for bubble tight shut off

Joint Body Leaks

Fire Safe Design

Speed of Closure

Page 4: Valve Presentasion

Type

The Gate Valve The Globe Valve

The Needle Valve The Plug or Ball Valve

The Butterfly Valve Check or Non-Return Valves

Diaphragm Valve Pinch Valve

Page 5: Valve Presentasion

Pressure Relief Devices

Code Requirements

• All pressure vessels subject to overpressure shall be protected by a pressure relieving device • Liquid filled vessels or piping subject to thermal expansion must be protected by a thermal relief

device • Multiple vessels may be protected by a single relief device provided there is a clear, unobstructed

path to the device • At least one pressure relief device must be set at or below the MAWP (Maximum Allowable Working

Pressure)

Relieving pressure shall not exceed MAWP (accumulation) by more than: • 3% for fired and unfired steam boilers • 10% for vessels equipped with a single pressure relief device • 16% for vessels equipped with multiple pressure relief devices • 21% for fire contingency

Page 6: Valve Presentasion

Pressure Relief Devices

General Types Safety Relief Valve

Direct acting type

Conventional Spring Loaded Advantages • Most reliable type if properly sized and operated • Versatile -- can be used in many services Disadvantages • Relieving pressure affected by back pressure • Susceptible to chatter if built-up back pressure is too high

Balanced Bellows Spring Loaded

Advantages • Relieving pressure not affected by back pressure • Can handle higher built-up back pressure • Protects spring from corrosion Disadvantages • Bellows susceptible to fatigue/rupture • May release flammables/toxics to atmosphere • Requires separate venting system

Page 7: Valve Presentasion

Pressure Relief Devices

General Types Safety Relief Valve

Pilot operated type

Advantages • Relieving pressure not affected by backpressure • Can operate at up to 98% of set pressure • Less susceptible to chatter (some models) Disadvantages • Pilot is susceptible to plugging • Limited chemical and high temperature use by “O-ring” seals • Vapor condensation and liquid accumulation above the piston

may cause problems • Potential for back flow

Page 8: Valve Presentasion

Pressure Relief Devices

Rupture Discs

General

A rupture disc is a thin diaphragm (generally a solid metal disc) designed to rupture (or burst) at a designated pressure. It is used as a weak element to protect vessels and piping against excessive pressure (positive or negative).

They are often used as the primary pressure relief device. • Very rapid pressure rise situations like runaway reactions. • When pressure relief valve cannot respond quick enough.

They can also be used in conjunction with a pressure relief valve to: • Provide corrosion protection for the PRV. • Prevent loss of toxic or expensive process materials. • Reduce fugitive emissions to meet environmental requirements.

Page 9: Valve Presentasion

Pressure Relief Devices

Rupture Discs

When compared with PR valves, rupture discs have:

Advantages • Reduced fugitive emissions - no simmering or leakage prior to bursting.

• Protect against rapid pressure rise cased by heat exchanger tube ruptures or internal deflagrations.

• Less expensive to provide corrosion resistance. • Less tendency to foul or plug. • Provide both over pressure protection and de-pressuring. • Provide secondary protective device for lower probability

contingencies requiring large relief areas.

Disadvantages • Don’t reclose after relief. • Burst pressure cannot be tested. • Require periodic replacement. • Greater sensitivity to mechanical damage. • Greater sensitivity to temperature

Page 10: Valve Presentasion

Pressure Relief Devices

Rupture Discs

Type

Conventional Tension-Loaded

Advantages • Broad range of applicability for gas and liquids • Available in large variety of sizes; burst pressures, temperatures

and materials and coatings. Disadvantages • Have tendency to fragment. • May require vacuum support. • Are not fail safe if installed upside down with vacuum support

(require more than 1.5 X Burst Pressure). • Subject to premature failures if operating pressure exceeds 70% of

BP.

Page 11: Valve Presentasion

Pressure Relief Devices

Rupture Discs

Type

Pre-Scored Tension - Loaded

Advantages • Broad range of applicability. • Readily available sizes, burst pressures, materials, etc. • Non-fragmenting. • Don’t require vacuum support. • Fail safe - (Rupture prematurely if upside down). • Can operate to 85% of BP.

Page 12: Valve Presentasion

Pressure Relief Devices

Rupture Discs

Type

Composite

Advantages and disadvantages similar to conventional tension-loaded type. Advantages • Allow use of corrosion resistant materials in lower

pressure service and smaller sizes than solid metal discs.

Page 13: Valve Presentasion

Pressure Relief Devices

Rupture Discs

Type Reverse Buckling With Knife

Blades

Advantages • Wide range of sizes, materials, pressures and

temperatures. • thicker than conventional due to “snap action.” • Don’t require vacuum support. Disadvantages • Not fail safe. a. Blades corrode or get dull. b. Blades can be left out. c. Excessive burst pressure if upside down. d. Unsuitable in liquid service - (no snap action). e. Damage causes premature reversal. f. Subject to roll over.

Page 14: Valve Presentasion

Pressure Relief Devices

Rupture Discs

Type

Pre-Scored Reverse Buckling

Advantages • Most of the advantages of reverse buckling. a. Non-fragmenting. b. Fail safe. c. Don’t need vacuum supports. d. Available in common sizes and materials. Disadvantages • Limited number of burst pressures/temperatures.

(Not for high pressures (too thick required) • Not effective in liquid service.

Page 15: Valve Presentasion

Type

The Gate Valve

General Flow is controlled by rising or lowering the valving element. Gate Vales are not usually used to regulate flow because the valving element can be damage when in the partially open position. Similarly, they also limit the pressure drop across the valve when fully open

Advantages • Gate valve opens or closes slowly, which prevents fluid hammer and subsequent damage to piping system • They need long operation time since setting the valve to the fully open or closed position requires the handle

to be turned many time • Good choice for on-off service • Full flow, low pressure drop • Bidirectional

Disadvantages • This is not suitable for throttling applications. • It is prone to vibration in the partially open state. • It is more subject to seat and disk wear. • Repairs, such as lapping and grinding, are generally more difficult to accomplish.

Page 16: Valve Presentasion

Type

The Globe Valve

General A globe valve is a linear motion value used to stop, start and regulate fluid flow, the three primary body designs for globe valve are Z-body, Y-body and angle.

Advantages • Recommended for throttling applications • Good for frequent operation • Easy to repair

Disadvantages • Flow part cause a significant pressure drop • Globe valve are more costly than alternative valve

Page 17: Valve Presentasion

Type

The Needle Valve

General They are used to make relatively fine adjustment in the amount of fluid flow.

Page 18: Valve Presentasion

Type

The Ball Valve

General A ball valve is a rotational motion valve that uses a ball-shaped disk to stop or start fluid flow

Advantages • Maintains and regulates high volume, high pressure and high temp flow • Low purchase and maintenance costs. • No lubrication requirements • Give tight sealing with low torque • Time of valve operation is minimized • Can be used for throttling service • Can handle fluid with suspended solids

Disadvantages • Have relatively poor throttling characteristics • Difficult to clean, leads to contamination

Page 19: Valve Presentasion

Type

The Butterfly Valve

General A butterfly valve are rotary motion valve that is used to stop, regulate and start fluid flow.

Advantages • They are suitable for large valve applications. • Compact, lightweight design. • The maintenance costs are usually low. • Pressure drop across a butterfly valve is small. • Used with chemical or corrosive media.

Disadvantages • Difficult to clean • Throttling limited to low differential pressure • Potential for cavitation and choke • Unguided disc movement is affected by flow

turbulence

Page 20: Valve Presentasion

Type

The Check Valve

General • Check valve are designed to prevent the reversal of flow in piping system. • These valve are activated by the flowing material in pipeline. The pressure of the fluid passing through the

system open the valve, while any reversal of flow will close the valve. Closure is accomplished by the weight of the check mechanism, by back pressure, by a spring, or by a combination of these means.

• The general type of check valve are swing, titling disk, piston, , and stop

Page 21: Valve Presentasion

Type

The Diaphragm Valve

General A diaphragm valve is a linear motion valve that is used to start, regulate and stop fluid flow. The name derived from its flexible disk, which mates with a seal located in the open area at the top of the valve body to form a seal.

Advantages • Valve components can be isolated from the process fluid • Valve construction prevents leakage of the fluid without the use of a glad seal (Packing)

Disadvantages • The diaphragm becomes worn more easy and regular maintenance is necessary • These type of valve are generally not suited for very high temperature fluid and are

mainly used on liquid system

Page 22: Valve Presentasion

Type

The Pinch Valve

General A pinch valve is the simplest valve design, it is a linear motion valve that is used to start, regulate and stop fluid flow. It uses a rubber tube (pinch tube) to control the fluid.

Advantages • They are ideally suited for the handling of slurries, liquids with large amounts of suspended solids and system that convey solids pneumatically

• Can be used for application where corrosion or metal contamination of the fluid might be problem.

• The flow passage is straight without any crevice • There are no internal moving parts in contact with the fluid • Low maintenance due to wear or pressure • Minimum items to change. Tube ONLY

Disadvantages • Cannot be used in high temperature/pressure application • Cannot be used with gas media

Page 23: Valve Presentasion

Operator

A Diaphragm The valve is operated by an air powered diaphragm. A diaphragm valve is a manual or control type block valve which uses a diaphragm as the closing device. The diaphragm valve is usually used to isolate or block flow. Because the material of the membrane can chemically degrade, diaphragm valves are used under the conditions of low pressure and a limited temperature operating range.

Diaphragm valves may be used for regulation of most gases and liquids. There are two types of diaphragm valves available: 1. Weir 2. Straight through flow.

Page 24: Valve Presentasion

Operator

An Electric Motor

These valves are generally of large size and are used for different applications such as Pump discharge etc. Can be of various types e.g. Gate/ Ball/ Butterfly etc. with actuator control. Design of Motors and valves can be different. An electric motor is mounted on the valve and geared to the valve stem so that when the motor operates the valve will open or close. For this MOV, motor operated with actuator control from local panel or from control room is required.

Applications of motor operated valves • Whenever frequent operation is required. • Valves located in remote, inaccessible or hazardous places.

Control Motorized

More Faster Faster

Analog Control Element Digital Control Element

pressure control, flow control, temperature control flow control

in closed loop control predominantly open loop

used for precision control not usually used for precision control

Page 25: Valve Presentasion

Operator

A Solenoid

A solenoid valve is an electromechanically operated valve. The valve is controlled by an electric current through a solenoid. Solenoid valves are the most frequently used control elements in fluidics. Their tasks are to shut off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.

Page 26: Valve Presentasion

Reference

1. http://articles.compressionjobs.com/articles/oilfield-101/4393-valves-pipelines-gate-globe-needle-angle-plug-ball-butterfly-check?showall=1 2. www.slideshare.net/mohdalaamri/valves-presentation 3. Pressure Relief Devices Scott Ostrowski 4. http://www.enggcyclopedia.com/2012/05/motor-operated-valve/ 5. http://www.rpi.edu/dept/chem-eng/Biotech-Environ/valves/diaphragm.html 6. http://www.spiraxsarco.com/Resources/Pages/Steam-Engineering-Tutorials/pipeline-ancillaries/isolation-valves-linear-movement.aspx