Abstract: A device for preheating gases of waste lines, particularly for the catalytic purification of exhaust gases comprises a conduit for the passage of the waste gases which is provided with a widened portion defining an annular flow passage around a portion of the conduit for preheated gases with a through flow for the heated gases and the waste gases out the opposite end of the conduit. The preheated gases are generated in a tubular burner which is tangentially connected into the waste gas conduit at the location of the widened section thereof. The burner includes means for feeding air and fuel into the end of the tubular burner and igniting them in a combustion chamber thereof for flow into a partially annular space around a portion of the waste gas conduit through an intermediate convergent section into the flow path of the gases through the conduit.