| 摘要 |
Discharge electrodes each comprise a supporting tube (1) having a number of projections (2) each of which has a rounded surface (3) at its free end. The projections may be separate rod elements; or part-spherical embossments in the tube wall; or folds in wires attached to the tube, preferably lying in depressions extending longitudinally, helically or concentrically of the tube. <IMAGE> |
