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).
Technical analysis of a pump and gauge mechanism, focusing on the function of the bell plate under shock conditions.
| Identifier | ExFiles\Box 44\4\ Scan072 | |
| Date | 3rd May 1929 | |
| Messrs.Rolls-Royce,Ltd., Date 3.5.29 Page 3 of the pump. That is to say, one stroke of the pump, assuming complete volumetric efficiency, gives 1.3 cubic inches of air, and the total capacity of the bell is 1.6 cu.in. The writer has been running for the last month on a completely open ended bottom bell, which appears to behave in exactly the same way as one with a bell plate. We would suggest that if it is desired to invariably correct the gauge in one or two strokes of the pump, (assuming an air delivery period of 4 seconds), it would be perfectly satisfactory to increase the petrol exit hole to that shown on enclosed sample. Now that the safety factor of the gauge is provided for by pressure balance, we are not confident that the bell plate is at all necessary, and at present it is merely acting as a sort of baffle against spilling under very violent shock conditions on the road. By trying to imitate these conditions on the bench in a glass vessel, we do not appear to be able to find very much difference in the amount of air shaken out of the bell under violent shock conditions with the bell plate in or out, so that we do not think that it is playing a very important part in the present gauge arrangements. Naturally with no bell plate, all air delivered | ||