Massachusetts 2nd Class Fireman's Practice Exam

Why are baffles placed between the tubes of a boiler?

1. Slow down the rate of combustion

2. Prevent priming

3. Brace the tube bank

4. Direct the travel of flue gases

The correct answer is: Direct the travel of flue gases

Baffles are essential components in a boiler system, serving the primary function of directing the travel of flue gases. In a boiler, the efficient movement of flue gases through the tube bank is crucial for effective heat exchange; baffles help to guide these gases in a controlled manner, ensuring that they flow over the heating surfaces for the maximum possible time and surface area. This not only enhances heat transfer efficiency but also aids in maintaining consistent temperatures throughout the boiler, which is vital for optimal performance and safety. While options such as preventing priming and bracing the tube bank are related to boiler design and operation, they do not directly address the primary purpose of baffles. Priming refers to the carryover of water into the steam, and while baffles may have a secondary role in addressing this phenomenon by stabilizing water levels, their main function does not revolve around this issue. Similarly, while structural supports for the tube bank are important, especially in high-pressure boiler systems, baffles primarily focus on the flow of flue gases rather than providing physical support to the tubes. The correct answer highlights the importance of directing flue gas travel, which is vital for the efficient functioning of the boiler system.