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 procedure for filling thermostat units under vacuum and testing them, with a suggestion for preventing water system corrosion using zinc.
| Identifier | ExFiles\Box 41\3\ Scan269 | |
| Date | 19th January 1923 guessed | |
| (2) the liquid with which it is desired to fill them, the temperature of the liquid being low. We subject the whole to a high vacuum so as to extract all the air from the thermostat units. On relieving the vacuum, atmospheric pressure will completely fill the thermo- stat unit with the liquid. Keeping them well covered with the liquid we fish them out one by one, and plug and seal by solder the tiny hole mentioned above. The hole is small so that the liquid will not run out, be- tween them being withdrawn from the liquid and the seal- ing process. It will also facilitate the sealing. In testing we think they should be inserted into water of 3 temperatures - (1) the unit should remain in the collapsed form, (2) hot enough to expand to it's full stroke, (3) boiling temperature to be sure that the unit is sound mechanically, and tight. I suggest somewhere in our water system, where- ever convenient, we fit a piece of zinc, such as on the cylinder covers. This piece of zinc being electro- positive should be the first to be eaten away should the circulating water be acid, or alkaline. We think you might be able to test this experimentally. R.{Sir Henry Royce} 70 | ||