A double-seated control valve is a type of control valve that features two separate valve plugs or discs within a single valve body. Each plug or disc controls the flow through its respective seat, allowing for more precise control over the flow rate and providing enhanced throttling capabilities. Here are the main components and features of a double-seated control valve:

1. Body:

   • The body of the double-seated control valve provides the main structure and contains the internal components. It typically has two inlet and outlet ports, each corresponding to one of the valve plugs or discs.

2. Seats:

   • Double-seated control valves have two seats, one for each valve plug or disc. The seats provide a sealing surface against which the plugs or discs close to control the flow of fluid through the valve body.

3. Valve Plugs or Discs:

   • Double-seated control valves feature two valve plugs or discs, each mounted on a separate stem or shaft. These plugs or discs are designed to move independently of each other to regulate the flow through their respective seats.
   • The dual-plug design allows for precise control over the flow rate and provides better throttling characteristics compared to single-seated valves.

4. Stems or Shafts:

   • The stems or shafts connect the valve plugs or discs to the actuator mechanism, allowing them to be moved to adjust the flow rate through the valve.
   • In some designs, each stem or shaft may be connected to a separate actuator, providing independent control over each plug or disc.

5. Bonnet:

   • The bonnet is the top cover of the valve body and provides access to the internal components for maintenance and repair. It is typically bolted or screwed onto the body.

6. Actuator:

   • Double-seated control valves may be equipped with pneumatic, hydraulic, electric, or manual actuators to automate the operation of the valve. The actuator controls the movement of the valve plugs or discs to adjust the flow rate as needed.

7. Trim:

   • The trim of the double-seated control valve includes all the internal components that come into contact with the fluid flow, such as the valve plugs or discs, seats, and associated seals.
   • The trim is designed to provide smooth, stable, and precise control over the flow of fluid through the valve.

Double-seated control valves are commonly used in applications where precise control over the flow rate is required, such as in process industries, power plants, and water treatment systems. They offer advantages such as improved throttling characteristics, enhanced flow control, and increased rangeability compared to single-seated valves. However, they may also be more complex and require careful design and maintenance to ensure proper operation.