training valves fainal 2013 august

1BRAND-EPC.PPT Slide No: 1

Introduction Training

Valves


VALVES FUNCTION

valves are used for the following purposes :

To start and stop flow of fluids

To regulate, throttle and control fluid flow or pressure

To prevent back-flow

To relieve excess pressure / vacuum

Control direction of fluid

MAIN VALVE TYPES

Gate valves are generally used in systems where low flow resistance for a fully

open valve is desired and there is no need to throttle the flow.

Globe valves are used in systems where good throttling characteristics and low

seat leakage are desired and a relatively high head loss in an open valve is

acceptable.

Ball valves allow quick, quarter turn on-off operation and have poor throttling

characteristics.

Butterfly valves provide significant advantages over other valve designs in weight,

space, and cost for large valve applications

Valves in Petroleum Processing Industry



Gate VALVE

This is the most common type of valve in use in industry and is used to start or stop the flow of fluids. It

gives a positive shut-off when closed and is often used as a 'Block Valve' for isolating systems.

The gate valve MUST be either FULLY CLOSED or FULLY OPEN and NEVER USED TO CONTROL

FLOW, as the fluid velocity will erode the valve internals - gate and body seats .. etc.

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StaticDepartment


GLOBE VALVE

The Globe valve is used where control of fluid flow or pressure is required and it can be operated in any position

between open and closed.


StaticDepartment


Ball VALVE

These valves give a more streamline flow in their operation. The valve port is about the same size as the

internal pipe diameter. They are operated simply by turning a handle through 90°. They can give a fairly tight

shut-off and some degree of control.

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Butterfly VALVE

The Butterfly valve is designed to give full flow with some control capability. Normally, this type of valve

does not give positive shut-off but, present-day technology, using new Polymers and higher temperature

ratings, has enabled the construction of butterfly valves having a 'Bubble-tight' shut-off.

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training valves fainal 2013 august

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