Abstract: For generating an electrostatic field, a coagulator for an exhaust gas scrubbing system for internal combustion engines has an electrode, which extends in an insulated manner within a housing. The electrode is braced on the housing via at least one insulator. To prevent the formation of a short-circuiting bridge between the electrode and the housing as a consequence of the deposition of so-called agglomerates on the insulator surface, the insulator is heated to a surface temperature of over 400.degree. C. In order to attain an extremely compact insulator and so that heating it will require little energy, the insulator is embodied in disk-like fashion and has a spiral heating conduit, through which hot gases flow, disposed in its interior. The hot gases are diverted from a partial flow of the engine exhaust gas, or are drawn from the exhaust gas of a soot burner.