What is a boiler?

A boiler is defined as a closed metal container where water is heated to produce steam or heated water. This process is fundamental in various industrial applications, as well as in heating systems for buildings.

Boilers operate by applying heat to water, which turns into steam or heated water, and this steam can be used for power generation, heating, or various industrial processes. The design and materials used in constructing a boiler are crucial because they need to withstand high pressures and temperatures.

Understanding this definition is important in the context of stationary engineering, as it lays the foundation for comprehension of systems involving steam generation and its applications. The other choices, while relevant to industrial mechanics, do not accurately describe what a boiler is or its primary function in generating steam or hot water.