In steel plate heating boilers, what is the purpose of the thin steel installed in the firetubes?

In steel plate heating boilers, the thin steel installed in the firetubes serves to give the gases a swirling motion. This design feature is critical because swirling gases can improve heat transfer efficiency between the combustion gases and the boiler's water. The motion disrupts the flow of gases, creating turbulence that enhances the mixing of the gases with the surrounding water, which leads to more efficient heating of the water. This swirling effect helps in ensuring a more uniform temperature distribution within the boiler, allowing for better thermal performance and energy utilization.

While aspects like durability, insulation, and fuel efficiency are important considerations in the design of heating systems, they are not the primary functions of the thin steel in the firetubes. The swirling motion specifically contributes to optimizing the heat exchange process, making it a vital part of the boiler's operation.