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Types of Valves

1. Globe valve: ( Types of valves )

Globe valve: It operates by reciprocating action of disc or plug. The disc or plug moves to or away from the seat thereby stopping the fluid flow or allowing the fluid to flow. The disc or plug seats over the valve seat. The valve seat can be removable. Pressure drop in the globe valve is high.

The valve can be manually operated or power actuated or automatic actuated. Globe valves are available from 12 mm to 300 mm size and their temperature and pressure limits are 550 C and 150 

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2. Gate valve: ( Types of valves )

Gate valve: Gate valve functions by the reciprocating action of disc in its body. It can have a single disc or double disc. It is used for shut off operation. In double disc valve shut off is good.
Gate valve can have rising or non-rising stem. Gate valves are available in various sizes ranging from
12 mm to 300 mm and even more. Gate valve is light in weight, economic and offers low pressure drop. Conduit type gate valve is common in chemical process industries because it gives accurate flow control. Gate valve can be used upto 20 kg/cm2 and upto 675°C. Material of construction for gate valve is cast iron, carbon steel, stainless steel, ductile iron, bronze, nickel alloys etc. Rotating disc type gate valve with quick action lever actuator.

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3. Ball valve: ( Types of valves )

Ball valve: Ball valve has a spherical plug. The spherical plug is a controlling element. They are widely used in chemical process industries. It is used where throttling and shut off combination is required. It offers good flow characteristics. Ball valve consists of a two way globe and the ball rotates between resilient seats. It is compact and requires low maintenance and no lubrication. It is available in venture pattern, reduced and full port patterns. By giving a quarter turn to the ball, the valve can be closed or opened. The valve does not give good throttling. It can be available in size from 6mm to as large as 900mm. It can be used for pressures upto 500 kg/cm and temperature upto 300°C.
Full port ball valve is shown below

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4. Plug valve: ( Types of valves )

Plug valve: Plug valve is used for on-off service. It is the oldest type of valve. The main parts of a valve are body, plug and cover. Plug can be cylindrical or tapered. The plug has a slit cut in it to allow the fluid to flow. It provides a straight line and can be opened or closed just by giving a quarter turn.

Plug valve can be made to have one or more openings to change the direction of flow. It can be lubricated or non-lubricated type.

Plug valves have the advantages such as quick action, easy operation, minimum space for installation, light in weight and high capacity. It can be used for slurry handling and pulp handling. Valves with spherical plug are useful in automatic process control operations.
Plug valve can be fabricated from cast iron, stainless steel, copper, alloys, nickel alloys and other corrosion resistant alloys. Tapered plug valve without lubrication is shown.

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Lubricated plug valve is used in oil industry while non-lubricated valve is preferred where contamination is to be avoided. Plug valves are available in size from 6mm to as large as 750 mm.

Lubricated plug valve can have high pressure rating upto 300 kg/cm2 and temperature rating upto 300°C. Single port valve with lubrication arrangement is shown.


Post time: Jul-28-2021