in this exemplary embodiment is placed in a spatial area where the collector forms an arc and therefore does not require so much installation space in the examples of fig1 a to 16 d collectors 170 171 and 172 are provided accordingly and the filling tube is shown entering the collector from the side from the filling opening or from above whereby the filling tube angled in an i shape is oriented along the longitudinal direction of collector 172 alternatively the filling tube can also be arranged parallel to the collecting tanks in the delta shaped spatial areas according to reference character 177 or 178 fig1 a to 17 d show a variant in which the filling tube enters the collector from a bottom side of the tube base of the collecting tank see fig1 c where filling tube 179 enters the collector through a lower edge area 180 accordingly in a simplified design filling tube 179 can be oriented substantially perpendicular downward so that it is oriented more or less parallel to side wall 181 of the collector and takes up as little space as possible viewed from above according to fig1 a this arrangement is advantageous such that the header cannot be seen fig1 and 19 show further approaches to the method of the invention for closing a filling opening of a collecting tank of a heat exchanger in this regard fig1 in block 190 shows the construction of the evaporator by bundling and clamping of the tube fin blocks in block 191 tube installation takes place by pressing the tubes into the provided tube openings in the tube base in block 192 the heat exchanger is brazed.