How many internal flue tubes are housed inside a Lancashire boiler shell_________________?
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Answer: C. two
Explanation
A Lancashire boiler is characterized specifically by having two large internal longitudinal fire tubes running through its shell. These twin parallel internal flues house the grates and combustion gas pathways for efficient steam generation. Housing two separate fire tubes maximizes the internal heating surface area within the cylindrical boiler shell. Lancashire boilers are traditional natural-draft shell boilers invented in the nineteenth century for industrial power. The dual-flue design allows operators to clean and fire each furnace tube alternately while maintaining steam pressure. Hot combustion gases travel through the internal flues, reverse at the rear, and return via external side flues.
Option A describes shell boilers without internal fire tubes, which do not match standard Lancashire designs. Option B represents Cornish boilers, which feature only a single internal flue instead of two. Option D suggests four tubes, which is structurally impractical for standard cylindrical shell boiler diameters.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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