Aux 1 Unit 3 Q6

1 / 10

Which material is typically used for the valve seat in a globe-type screw lift valve used for seawater service, and why?

D) Aluminum, because it has good thermal conductivity

A) Rubber, because it provides a flexible seal

B) Bronze, because it is durable and resistant to seawater corrosion

C) Plastic, because it is lightweight and inexpensive

2 / 10

Why is it important for the valve stem in a globe-type screw lift valve to be made from a corrosion-resistant material?

A) To reduce the overall weight of the valve

C) To ensure the valve remains aesthetically pleasing

D) To improve the valve's ability to handle high pressure

B) To prevent the stem from seizing or corroding in a seawater environment

3 / 10

How is the disc in a globe-type screw lift valve operated to control the flow of seawater?

D) By a temperature-sensitive actuator

C) By a pressure differential across the valve

B) By manually turning a handwheel, which raises or lowers the disc via the stem

A) By an automated control system

4 / 10

How does the flow path in a globe-type screw lift valve typically differ from that in a gate valve?

D) The flow path in a globe valve is circular, improving flow efficiency

A) The flow path in a globe valve is straight, while in a gate valve, it is S-shaped

C) The flow path in a globe valve is direct, minimizing pressure drop

B) The flow path in a globe valve is S-shaped, providing better throttling capabilities

5 / 10

Which material is most commonly used for the valve body of a globe-type screw lift valve in seawater service, and why?

B) Stainless steel, because it is corrosion-resistant

D) Aluminum, because it is easy to machine

A) Brass, because it is lightweight

C) Cast iron, because it is inexpensive

6 / 10

What is the primary function of a globe-type screw lift valve in a seawater service system?

A) To regulate the flow of seawater

D) To filter debris from seawater

C) To mix seawater with freshwater

B) To prevent the backflow of seawater

7 / 10

In a globe-type screw lift valve, what ensures a tight seal when the valve is closed?

A) The stem's material

D) The size of the handwheel

C) The thickness of the valve body

B) The design of the disc and valve seat

8 / 10

What component of the globe-type screw lift valve moves to control the flow of seawater?

B) The handwheel

A) The valve body

C) The disc (or plug)

D) The bonnet

9 / 10

What is the role of the bonnet in a globe-type screw lift valve?

B) To house and protect the internal components, such as the stem and disc

C) To filter debris from the seawater

A) To direct the flow of seawater

D) To regulate the temperature of the seawater

10 / 10

What is a key advantage of using a globe-type screw lift valve in seawater service compared to other valve types?

A) It offers quick on/off operation

D) It requires no maintenance

C) It is less expensive than other valve types

B) It provides precise control over flow rates

Your score is