Which device is responsible for transforming liquid fuel into vapor for combustion?

The device responsible for transforming liquid fuel into vapor for combustion is the oil burner. An oil burner is specifically designed to atomize the liquid fuel, creating a fine mist that mixes with air, allowing for more efficient combustion in the combustion chamber. This atomization process is crucial because it enhances the surface area of the fuel, facilitating better mixing with air and improving combustion efficiency.

In addition, while other devices play important roles in the overall heating system, they do not specialize in the vaporization process. The combustion chamber is where the actual burning occurs, the heat exchanger is responsible for transferring heat from the combustion process to the surrounding environment or to a fluid for heating purposes, and the Venturi tube is involved in creating a vacuum that aids in fuel delivery but does not transform the liquid fuel itself. Therefore, the oil burner is the most appropriate choice for vaporizing liquid fuel in preparation for combustion.