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).
Leaflet explaining the benefits and operation of the B.W.P. Variable Level Oil Intake system.
| Identifier | ExFiles\Box 135\3\ scan0070 | |
| Date | 26th September 1934 guessed | |
| THE B.W.P. VARIABLE LEVEL OIL INTAKE (PATENTED) OIL PUMP ELIMINATES MANY ENGINE TROUBLES REDUCES REPAIR BILLS The illustration above shows the intake system commonly in use at rest. The crankcase contents have settled into layers. Observe that only sediment and water surround the pump intake—the first material to be pumped into the lubrication system. The illustration below shows the same system in operation. Sediment, water, solids and oil are completely mixed. The resultant mass is being constantly circulated through the bearing surfaces of the engine, causing undue wear. Many engine troubles, chief of which are scored cylinders and worn bearings, resulting in large repair bills, are due directly to faulty lubrication. The B.W.P. Variable Level Oil Intake is a movable device which floats in the oil; it thus draws from a point just below the top level. It is a simple matter to demonstrate that abrasive impurities and water will sink to the bottom of a crank case and will remain there if not disturbed by pump suction. The universal practice hitherto employed in engines which circulate oil from the crank case, has been to draw the oil into the pump from a fixed point, usually about half an inch, or less, from the bottom of the case, invariably in the contaminated zone. This low intake point has been necessary in the past in order to secure correct functioning with a low oil level, or alternatively, when due to sharp turns or sudden brake applications, the oil would be likely to be thrown away from an intake placed elsewhere. The B.W.P. Variable Level Oil Intake is not a filter; it operates on the principle of isolation, rather than of filtration. Its isolation efficiency is from 75% to 98%, depending on the type of service. This efficiency is CONSTANT and applies to ALL of the oil circulated by the pump, rather than to a certain portion that may be by-passed through any cleaning element. Oil, water and solids will invariably settle into three well defined layers; thus with an intake placed near the bottom of the case, the solid particles and the water will be drawn into the lubrication system first. In cold weather the B.W.P. Variable Intake is of special importance for two additional reasons. Firstly, the water layer frequently freezes and where the intake is in or below this layer, circulation is totally stopped. Secondly, the B.W.P. Intake, being movable, has the ability to go to the oil when the oil cannot flow to it. This means that the lighter oils commonly used in winter to assure circulation, need not be used in engines equipped with the B.W.P Intake. On engines thus fitted, it is possible to use oil of the proper body for correct lubrication at high operating temperatures. This oil would, of course, be too heavy to be used in an engine with a fixed oil intake at low temperatures. It is obvious that with the B.W.P. Intake, there is no possibility of air becoming trapped and locking the intake system which occurs with fixed intakes, when rounding sharp turns or through the violent application of brakes. | ||