Letter from The Zenith Carburetter Co. regarding a carburettor test setup using an orifice box and associated drawings.
| Identifier | ExFiles\Box 122\4\ scan0128 | |
| Date | 6th May 1938 | |
| THE ZENITH CARBURETTER CO. Limited. Sheet No. 2........ Messrs. Rolls-Royce Ltd. 6/5/38 All connections made to the table are airtight. Details of the connection for manometer for air supply to the test hood and from the hood, together with petrol connection, and details of throttle control gland, are shown on a separate Drawing X.2014 The orifice box is shown on Drawing X.1459, and the door for that box is shown on X.1460. In this connection we might say that such a large elaborate door is not necessary with the plant when the test table as shown in X.2014 is used, but until recently we ourselves did not use a test table but we put the carburetter inside the box shown on Drawing X.1459 so that the aspirated air passed through the orifices into the box, then through the intake of the carburetter and out of the carburetter to the blower; and in this case, of course, the carburetter was fixed to one side of the box by means of an airtight joint. In the arrangement at present used the box is sealed up and the orifices are inserted in holders, or apperture rings, which are a permanent fixture on the sides of the orifice box. The detail of these apperture rings is shown on Drawing X.1461. The orifices themselves are made from 1/32" thick planished sheet steel perfectly flat, and the orifices have sharp edges. In our own case we have arranged for six such apperture rings on the box, so that it is possible to have six orifices in operation at once. The orifice which we use is 2" in diameter, and you will find that you would require all six in operation when testing the EEC-42 carburetter for the Phantom III to its limit. We send you these drawings as a preliminary. We have already sent you the address of the people who can supply the blower, and of the firm who can supply the rotameters for measuring the rate of fuel flow. | ||
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).