Abstract: Heat exchanger or heat accumulator bodies which are simple to produce. The bodies consist of a stack of extruded hollow chamber panels with plane smooth outer walls and webs that join the outer walls in a single piece. The hollow chamber panels are joined to one another in the stack on the front side by locking connections. The locking connections can be produced with an inserted electrical band heater, by glue seams, or by undercut interlockings. The hollow chamber panels are not joined to one another in the in-between areas or are not everywhere joined in the in-between areas.

Abstract: What is disclosed is a closure for closing the edge of a webbed structure having openings formed therein, said closure comprising a strip of flexible material having a plurality of projections formed thereon in a predetermined spaced relation selected to permit insertion of said projections into at least some of said openings, at least some of said projections including means for frictionally engaging the inner surfaces of the openings into which they are inserted to hold said strip on and against the edge of the webbed structure.