What is a characteristic of an internally fired boiler?

An internally fired boiler is designed with a furnace that is surrounded by water, which is a key characteristic of this type of boiler. This design allows for more efficient heat transfer from the combustion gases to the water, as the water is in direct contact with the heated surfaces of the furnace. This configuration not only improves thermal efficiency but also helps to prevent overheating, making the operation safer and more effective.

In contrast, internally fired boilers are typically suitable for a range of applications, not limited to high-pressure steam, and they generally do not rely on external heating sources. They can be utilized in various scales and industries, not exclusively small-scale applications, further highlighting the versatility of this boiler design.