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).
Recession valve tests for J.E.II. type shock dampers with a Bellows Governor.
| Identifier | ExFiles\Box 179b\4\ img026 | |
| Date | 11th April 1933 | |
| To Hdy.{William Hardy} from Hs{Lord Ernest Hives - Chair}/WB.{Mr Brazier/Mr Bell} JEII. TYPE SHOCK DAMPERS. RECESSION VALVE TESTS. R.R.Sch.284 Bellows Governor Controlled. It had been previously ascertained that there was a tendency for the external pressure oil to recede along the pipe line. With a view to preventing this, tests were taken with a valve fitted to the external pressure inlet banjo connections to allow as large an inward flow as possible, combined with a small return leak to check the recession. With the damper loads set at 35/35 lb. the governor pressure required to give the same maximum damper pressure as obtained with a 90 lb. setting at 45 R.P.M. 4" stroke was found to be 4 lb/sq.in. - before fitting the recession valve. Maintaining the governor pressure at 4 lbs/sq.in., diagrams were taken at 90, 135, and 180 R.P.M. Then repeated with a recession valve fitted, but no return leak provided, the maximum pressures were increased, and diagrams taken at 45 R.P.M. before and after introducing the governor pressure showed that the pressure was retained in the bellows - as was expected. Release vents of various diameters were then drilled - as shown in Hs.{Lord Ernest Hives - Chair}981. and the tests repeated. With one .062" diameter release vent, the diagram was practically equivalent to that obtained without the valve, and when reduced to .032" diameter the diagram was not increased. Not until the release vent was reduced to .015" - rather an impracticable size - was an increase of maximum pressure obtained. Tests were taken with both ball and bakelite disc valves, the latter being lightly spring loaded. The results obtained with both types were the same, there being a slight advantage gained with the ball valve, in that it was more definite in seating. This was more evident when diagrams were taken at 1" stroke. | ||