| 摘要 |
In reservoirs which are operated using liquid nitrogen as coolant there is often the need to be able to read off the particular level of the liquid nitrogen in a direct optical fashion at the reservoir. Such an optical read off is facilitated by a tube (5) which comes from the bottom of the reservoir and is pressurised with liquid nitrogen. The tube is led to the outside through the insulation of the reservoir to its upper rim and connected to a manometer (6). Because of the ingress of heat, there is gaseous nitrogen in the tube (5), leaving aside the region near the bottom. Depending on the level, this nitrogen is under a specific pressure, so that the display of the manometer (6) is a direct measure of the level. In addition, the manometer display can be used to operate an automatic refilling and alarm system, for example by means of inductive miniature proximity switches (14). <IMAGE> |
