Q4
With reference to air receivers and bottles explain with reasons:
(a) Why regular systematic internal inspection is advisable.
(4)
(b) Which internal areas of large receivers should receive particularly close examination?
(4)
(c) How bottles are inspected internally and what parts should be closely examined?
(4)
(d) How the condition of a bottle or receiver that cannot be inspected internally is checked.
(4)
Reference Answer
### (a) Reasons for Regular Systematic Internal Inspection of Air Receivers Regular internal inspection of air receivers is a critical safety and regulatory requirement. The primary reasons are: 1. **Detection of Internal Corrosion**: Air from compressors contains moisture which condenses under pressure. This water, combined with acidic gases (SOx, NOx) from the engine room atmosphere and oil carry-over, creates a highly corrosive electrolyte that accumulates at the bottom of the receiver. This leads to: * **Pitting Corrosion**: Localized and deep corrosion that can rapidly penetrate the shell thickness.
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