From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Blueprint detailing external pressure 'recession' valve tests for a bakelite disc valve and a ball valve.
| Identifier | ExFiles\Box 179b\4\ img029 | |
| Date | 11th April 1933 | |
| P-GM-33 Hs{Lord Ernest Hives - Chair} 981 RELEASE VENTS .380 .250 DIA BALL DISC VALVE BAKELITE BALL VALVE EXTERNAL PRESSURE "RECESSION" VALVE TESTS. ROLLS ROYCE, LTD. PRINT ROOM APR 11 1933 DERBY. | ||