Exam Question

### (a) Attachment of Mountings to Air Receiver Shell
Mountings on a high-pressure vessel like a main air receiver are not attached directly to the shell plate. Openings for connections create areas of high stress concentration, which could lead to fatigue cracking and catastrophic failure under pressure cycling. To prevent this, the shell is reinforced around the opening.
**Method of Attachment:**
1. **Reinforcing Pad (Compensating Ring):** A thick, shaped steel plate, known as a reinforcing pad or compensating ring, is welded onto the external surface of the receiver shell where the mounting is to be located. The cross-sectional area of this pad compensates for the material removed from the shell for the opening.