Directly fired intermittent furnace — identify the correct example Among common industrial furnaces, which one is a directly fired, intermittent (batch) type unit?

Introduction / Context:
Industrial furnaces are categorized by how heat is delivered (direct vs indirect firing) and by operating mode (intermittent/batch vs continuous). Recognizing furnace types is crucial for selecting burners, controls, and heat recovery systems.

Given Data / Assumptions:

• We compare common furnace names.
• “Directly fired” means the flame and hot products of combustion heat the work or the furnace chamber directly.
• “Intermittent” means cyclic charging, heating/soaking, and discharging (batch operation).

Concept / Approach:
A reverberatory furnace is directly fired: the flame and hot gases reflect (reverberate) off the roof into the hearth, heating the charge. Many reverberatories operate in batch mode (intermittent) for non-ferrous melting, holding, or reheating. In contrast, walking beam furnaces and tunnel kilns are typically continuous, with the stock moving through heating zones in a steady flow.

Step-by-Step Solution:

Verification / Alternative check:
Process flow descriptions for reverberatory units emphasize batch charging and tapping, consistent with intermittent direct firing.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing “directly fired” with “indirectly fired muffle” and mixing up operating modes when only the firing method is recognized.

Final Answer:
Reverberatory furnace