Cornish boiler — typical overall length range Select the most typical range for the length of a Cornish boiler used in industry.
-
A2 to 4.5 m
-
B3 to 5 m
-
C5 to 7.5 m
-
D7 to 9 m
-
E9 to 12 m
Answer
Correct Answer: 5 to 7.5 m
Explanation
Introduction / Context:Identifying realistic dimensional ranges helps distinguish classic shell boilers during design problems and site identification. The Cornish boiler, with a single internal furnace tube, has characteristic proportions different from the two-flue Lancashire boiler.Given Data / Assumptions:
- Traditional Cornish construction (single furnace flue inside a horizontal cylindrical shell).
- Industrial service at relatively modest pressures.
Concept / Approach:Handbook values place Cornish boiler lengths roughly in the mid-single-digit metres up to about 7 or 8 m for common sizes, while Lancashire shells are often longer. Among the choices, 5 to 7.5 m matches conventional practice most closely.
Step-by-Step Solution:
Compare with Lancashire: typically longer and larger diameter.Eliminate too-short ranges (2–4.5 m) for industrial outputs.Select 5–7.5 m as the representative span.Verification / Alternative check:Old design tables and museum specifications show Cornish boilers commonly around 5–7 m long for moderate duties.
Why Other Options Are Wrong:
- 2–4.5 m or 3–5 m: undersized for standard installations.
- 7–9 m: more typical of larger Lancashire units.
- 9–12 m: uncommon for the classic Cornish form.
Common Pitfalls:Confusing Cornish with Lancashire proportions; forgetting space for reversal chambers and brick settings.
Final Answer:
5 to 7.5 m