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).
The design and function of a U-tube valve for engine priming and petrol delivery.
| Identifier | ExFiles\Box 31\3\ Scan029 | |
| Date | 15th February 1915 | |
| -3- 15th. February, 1915. Wor{Arthur Wormald - General Works Manager}/EH1/D15215. valve, but in several other respects the U is the better. As regards the valve on U tube device, it should not be difficult to make one that will not stick, it is not necessary for it to be absolutely tight. For the valve to stick is the worst thing that can happen to it, but I cannot imagine why even this is a serious fault. The arrangement still does its job as regards priming, and blowing the petrol out of the float chamber is very little different to the flooding device which we fit to cars which allows the petrol to pour out of the float chamber every time they are used. I thought a slightly leady valve might be an advantage as it would wet the jets and enable the petrol to flow easier. The effect of the sticking valve can only make any difference when the engine is actually being primed, once the tap is turned off nothing can happen. There is one distinct advantage that the U tube has, that is the amount of petrol sprayed into the induction pipe can be regulated to suit the condition of the engine. For instance, a car that had been left out all night might need 20 strokes of the pump, whereas a car that has been left for one or two hours would only need 2 or 3 strokes to ensure it starting. We all appreciate how often it happens that after a car has been standing when it is cranked it fires once and then stops, in this case if the same amount of petrol is sprayed into the pipe as it takes to start the engine when it is cold it will be much too strong to the warm induction pipe vaporizing the petrol. This is | ||