Question

The number of tube and shell passes of a 3-6 pass exchanger will be:

• A. 3 and 6
• B. 3 and 3
• C. 3 and 5
• D. 6 and 3

Hint:

In a "shell-tube pass" notation, the second number typically refers to tube passes. Always clarify the convention being used in a given context.

Answer 1

The Correct Option is D

In heat exchanger terminology, the designation “$x$-$y$ pass exchanger” generally refers to:
- $x$ = number of tube passes, and
- $y$ = number of shell passes.
However, in some conventions, this is written in reverse — i.e., the first number refers to shell passes and the second to tube passes.
In this particular question, the format "3-6 pass exchanger" actually follows the second convention, where:
- The first number "3" indicates the number of shell passes, and
- The second number "6" represents the number of tube passes.
Thus, the exchanger has 6 tube passes and 3 shell passes. Therefore, the number of tube and shell passes will be:
\[ 6 and 3 \]
Let’s briefly verify the options:
- Option (1): 3 and 6 → reversed
- Option (2): 3 and 3 → incorrect
- Option (3): 3 and 5 → incorrect
- Option (4): 6 and 3 → correct
Hence, option (4) is the right choice.