Question

(a) Describe the procedure for entry into, and inspection of, the inside of a starting air bottle, stating the types of defects which may be present with their possible causes. (12)

(b) Describe the procedure of closing up the bottle and the initial pressurisation to working pressure. (4)

Answer 1

Part (a)

Procedure for Entry into, and Inspection of, the Inside of a Starting Air Receiver:

Ensure the starting air receiver is disconnected from compressors.
Use at least two valves that can be locked off.
If not possible, remove any cross-connecting pipes and fit blanks.
Use the drain valve to empty the receiver.
Monitor the pressure gauge to confirm the receiver is completely empty.
Open the inspection door to access the inside of the receiver.
Allow fresh air to circulate inside the receiver to ensure a safe working environment.
Verify the air quality inside the receiver.
Obtain an enclosed space permit to work.
Check if the internal coating is clear, without cracks or peeling.
Ensure it hasn't lifted due to the expansion and contraction of the receiver.
Inspect the entire shell for evidence of cracking.
Use a dye penetrant crack detecting spray if doubt persists.
Examine the inside surface for corrosion caused by condensation.
Pay special attention to cool areas like the bottom, ship's side, or surfaces exposed to ventilation blower air.
Investigate corrosion caused by oil carried over with the air, resulting in pitting corrosion.
Examine areas around high-pressure air outlets for erosion due to air velocity.
Check the joint face of the inspection door and its counterpart for corrosion or pitting.

Part (b)

Procedure for Closing up the Air Receiver and Initial Pressurization to Working Pressure:

If the receiver has been recoated, ensure the coating is dry.
Ventilate and test for combustible gases if coating fumes are present.
Remove all equipment from the receiver.
Ensure all valves and mountings are replaced and securely tightened.
Certify and seal the relief valve against tampering.
Use a new joint to replace the door.
Tighten the strongback to secure the door in place.
Open the filling valve and start the compressor.
Raise the pressure to 5 bar, inspect for leaks.
Raise the pressure to 20 bar, follow up the strongback on the door.
Finally, raise the pressure to working pressure (30 bar).
Follow up the strongback and check for any remaining leaks.
Confirm that the receiver is in good working condition.
Put the receiver into service for its intended operational use

✓ Verified Model Answer (Text Solution)

Procedure for Entry into, and Inspection of, the Inside of a Starting Air Receiver:

Procedure for Closing up the Air Receiver and Initial Pressurization to Working Pressure: