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).
Performance testing of two different sized air compressors.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan024 | |
| Date | 3rd October 1931 | |
| -2- Hs{Lord Ernest Hives - Chair}/Aln.6/MJ.3.10.31. Cont'd.{John DeLooze - Company Secretary} The volume of free air compressed in the bottles to 200 lbs. per sq.in. was 5.96 cu. ft. This was completed in 15.25 minutes by the large compressor and in 26 minutes by the small one. Compression, we found, took place practically isothermally as the heat capacity of the air compressed was negligible compared with that of the containing bottles. The curves show that the rate of rise at the high pressure end was 10.43 lbs. per sq. in. per min. in the case of the large compressor, and 6.95 lbs. per sq. in. per min. in the case of the small one. From these figures it is deduced that the deliveries at this pressure were .223 and .148 lbs. weight of air per min. respectively, or .289 and .193 cu.ft. of free air. These performances would, of course, diminish with increase of altitude. As these compressors have to work automatically without attention for starting and stopping, they must not leak back past the non-return valve or needle valve release. We therefore tested each one by leaving it for 15 hours or more overnight subjected to the bottle pressure of 200 lbs. per sq.in. No loss of pressure in the bottles could be observed in either case. We are proceeding to test the Claudel-Hobson air driven petrol pump, using the Hertzmark compressors and the air bottles for the air supply. Hs{Lord Ernest Hives - Chair}/F.J.Allen. Two prints attached. | ||