| 摘要 |
1,152,925. Making centrifugal pumps; welding by pressure. GRUNDFOS A.S. 31 July, 1967 [9 Aug., 1966], No. 35079/67. Headings B3A and B3R. [Also in Division F1] In the manufacture of a fluid flow device, e.g. an impeller, Fig. 5, or a guiding device for a centrifugal pump, all of the parts thereof are made by drawing or punching sheet material, preferably stainless steel, and are interconnected by welding. Projections 9 on vanes 3 are placed into openings 8 arranged in rows in shrouds 1 and 2. The projections 9 in the upper row of openings in each shroud initially extend beyond the outside surface of the shroud, see Fig. 3 (not shown), and are brought into contact with a respective ring 5 or 6, whereafter an electric current is fed to the impeller through copper electrodes so that the projections are resistance-welded to the ring which thereafter contacts the outside surface of the shroud. The openings 8 may be flared outwardly to provide spaces into which the projections can flow during welding. The projections located in the openings in the lower rows do not at any time extend beyond the outside surfaces of the shrouds, and are covered by rings 4 and 7 which are spot-welded to the shrouds. |
