parts 2 2 of the filter module 2 are mounted on each other in this embodiment the screwed connections of the flange 11 are tightened thereafter the filter elements 1 1 1 2 1 3 are inserted into the joined main parts 2 2 of the module housing 2 in such a way that their ends project at both sides beyond the face sides 2 1 of the module housing then the sealing elements 4 and the top plates 3 are mounted at the face sides 2 1 of the module housing 2 in this embodiment this occurs by means of a screwed connection this method can be used in accordance with the invention not only for the first mounting of the filter modules but is also preferably suitable for repairing damage to the coating surface e g by wear and tear during operation a further advantage is the favorable possibility of inspecting the surface advantages of the invention are further that also the cleaning of the module housing is facilitated and the exchange of individual main parts 2 2 of the filter module housing is possible in the case of damage other modifications of the present invention will be obvious to those skilled in the art in the foregoing teachings moreover while the present invention has been described with reference to specific embodiments and particular details thereof it is not intended that these details be construed as limiting the scope of the invention which is defined by the following claims it should be understood that the foregoing description is only illustrative of the present invention various alternatives and modifications can be devised by those skilled in.