Babcock and Wilcox (water-tube) boiler — orientation of water tubes: In a standard Babcock and Wilcox boiler, how are the water tubes arranged relative to the horizontal?
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Avertical
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Bhorizontal
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Cinclined
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Dspirally wound
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Erandomly staggered vertical risers only
Answer
Correct Answer: inclined
Explanation
Introduction:Recognizing the geometric arrangement of tubes helps identify boiler type and predict circulation behavior. The Babcock and Wilcox boiler is a classic water-tube design whose tube inclination promotes natural circulation and effective heat transfer.Given Data / Assumptions:
- Conventional Babcock and Wilcox layout with drums, headers, and tube banks.
- Natural circulation under steady firing.
Concept / Approach:In this boiler, the straight tubes are set at a small inclination (often about 15° to the horizontal). Hot gases flow externally across the tube bank, while water/steam mixture rises through the inclined tubes toward the steam drum, aiding separation and circulation.
Step-by-Step Solution:
Identify boiler family: water-tube with external gas flow.Recall construction: straight tubes between headers at a small upward incline.Conclude: tube orientation is inclined, not horizontal or vertical.Verification / Alternative check:Manufacturer drawings show the characteristic inclined tube bank feeding the upper steam drum, confirming the orientation.
Why Other Options Are Wrong:
- Vertical/horizontal: do not represent the standard Babcock and Wilcox geometry.
- Spirally wound/random risers: describe other boiler types or coil designs, not this one.
Common Pitfalls:Confusing with fire-tube boilers (gas inside tubes); assuming all water-tube boilers have vertical membrane walls only.
Final Answer:
inclined