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).
Page 2 of a letter from The British Thermostat Co., Ltd. explaining the function of their valve design.
| Identifier | ExFiles\Box 156\2\ scan0222 | |
| Date | 25th April 1939 | |
| Page 2 Rolls-Royce, Ltd., 25th April 1939. - - - - - - - - - - - - - - - - - - If, however, the pressure inside the header tank is greater than the steam pressure, due to the presence of air or other gases, the pressure acting upwards on the valve H will be greater than that inside the bellows due to steam pressure alone, and the valve will move upwards and release the pressure, until the pressure inside and outside the bellows is once more equalised. If the temperature continues to rise, the pressure between the stop C and the bellows plate D will increase, this being resisted by spring E, the tension of which is controlled by the nut J.{Mr Johnson W.M.} This will continue until E starts to collapse and the stop F attached to D comes into contact with the plate attached to the other end of the bellows G.{Mr Griffiths - Chief Accountant / Mr Gnapp} When this occurs, the bellows can no longer expand and the instrument proceeds to act as an ordinary relief valve and will blow off at higher pressures. The important point of this design is that the bellows plate D must come into contact with the variable stop C before the other stop attached to D comes into contact with the top plate G.{Mr Griffiths - Chief Accountant / Mr Gnapp} You will perhaps understand from this description that all the parts we shew are absolutely necessary, and thus, although ours is admittedly more complicated than the one shewn on your drawing, we regret that yours would not work. We shall be pleased to give you any further information you may require for this application, and on receipt of your order will make up a sample valve. Yours faithfully, THE BRITISH THERMOSTAT CO.,LTD., OH pp K.{Mr Kilner} M.{Mr Moon / Mr Moore} Petter. | ||