Patent Number: 052456447
Section: description

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a plan view of a prior art spacer, in which a first group of first webs 1 standing on end and extending parallel to one another is disposed at right angles to a second group of second webs 2 that are also standing on end and extending parallel, in the plane of the spacers. The webs 1 are split on the one or lower longer sides thereof, for instance, while the webs 2 have corresponding slits on the other or upper longer sides thereof, so that there is a plug-in connection 3 between each web 1 and a web 2 in which the webs intersect and are inserted into one another in the slits. In order to keep the webs in the illustrated position until they are welded together, and to lend greater stability to the welded connection, the webs of the prior art device have beads or so-called insertion buttons, between which the other web is engaged and guided. FIG. 1 also shows contact bumps 4 and springs 5, between which fuel rods of a fuel assembly are held. Flow lugs that are formed onto the webs in order to guide a coolant flow are not shown. In French or Belgian reactors, for instance, the flow lugs point into the openings of the grid formed by the spacer webs, on the trailing side of the spacer. In the prior art devices, the spacer webs and in particular the guide lugs formed onto them cause a high pressure loss. As mentioned above, it is an object of the invention to keep the pressure loss at the spacers as low as possible by means of different provisions. Therefore, according to the invention, the insertion buttons are omitted and a certain fixation of the plug-in connections for welding is attained only by means of impressions on the webs themselves. FIG. 2 shows a web 10 of the spacer of the invention, which has applicable insertion slits 11 on one side, defining web tabs beyond the slits. The insertion slit 11 is narrowed at one point, as a result of pinching-in of an impression or impressed indentation 12 on both sides. An arrow 13 indicates an insertion direction for the other web. At that location, the web has beads 14, which are formed from the material of the web and which bulge laterally when an indentation 15 is formed by pressing inward. The beads 14 provide guidance for insertion of the slit in the web of the other group, by forming a funnel tapering in the insertion direction. FIG. 3 shows a corresponding cross section taken along the line III--III of FIG. 2. FIG. 4 shows a corresponding longitudinal section taken along the line IV--IV. In FIG. 5, a web is shown with a plurality of such insertion slits. The novel plug-in connection is produced as follows: when the webs are inserted, the narrowed portion of one slit first scrapes over the smooth surface of the intersecting web, until a tab of the movable web is engaged by the funnel formed by the lateral beads 14 and thrust into the intended position. As it is thrust further, the movable web tab is then guided laterally, until the portion of the slit that is narrowed by the impressions 12 locks into place in the corresponding indentation 15 of the other web. The webs are then welded together.