| Year | 1957 |
| Date | 11-Apr |
| Volume | 116 |
| Issue | 2,916 |
| Page | 540 |
| Category | Workshop |
| Part | |
| Title | An automatic pressure control switch |
| Author | J.H.Turner |
| Notes | Compressor control. Easy to adjust, pressure sensitive element, preliminary adjustments, connecting up, final adjustments |