Pipefitter Valves, Fittings, and Pipe Materials 3

Question 1

Which valve type uses a rotating disc perpendicular to flow to achieve shut-off?

Accepted Answer

Butterfly valve

Answer

A butterfly valve uses a disc that rotates 90° within the pipe bore to open or close flow.

Question 2

What is the primary purpose of a swing check valve?

Accepted Answer

Prevent backflow

Answer

A swing check valve allows flow in one direction and automatically closes to prevent reverse flow.

Question 3

Schedule 80 pipe compared to Schedule 40 pipe of the same nominal size has:

Accepted Answer

Thicker wall and smaller bore

Answer

Schedule 80 has a thicker wall than Schedule 40, resulting in a smaller inside diameter and higher pressure rating.

Question 4

A 45-degree elbow is used instead of a 90-degree elbow primarily to:

Accepted Answer

Reduce friction loss and turbulence

Answer

A 45° elbow creates less turbulence and pressure drop than a 90° elbow by making a gradual direction change.

Question 5

Which material is most commonly used for high-pressure steam piping above 750°F?

Accepted Answer

Chrome-moly alloy steel

Answer

Chrome-moly alloy steel (such as P11 or P22) retains strength at elevated temperatures required for high-pressure steam service.

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