well fig4 shows a modified specific embodiment of a singe burner 100 39 in which parts corresponding functionally to singe burner 100 are characterized with the same reference numerals the difference consists only in the fact that supply chambers 16 16 39 are incorporated into housing 7 7 39 and in particular gas mixture nozzles 15 15 39 are so arranged that gas mixture jets 19 39 are directed parallel to and in synchronism with conveying direction 6 fig5 schematically represents a relevant pretreatment installation where the singe burner of the present invention whether 100 according to fig1 or 100 39 according to fig4 is combined with a yarn fixing installation heat setting installation the single carpet yarn thread 5 is reeled off from a supply spool 30 several times the number of supply spools being provided in an appropriate support stand as there are carpet yarn threads 5 treated side by side in singe burner 100 in question in order to assure a transition without stoppage in the preferred specific embodiment of the invention carpet yarn thread 5 runs as shown by solid lines into a singe burner 100 or 100 39 and then into a heat setting apparatus 200 which is generally known and therefore is not described further in which the yarn twist is fixed and the carpet yarn is bulked carpet yarn thread 5 is subsequently wound in each case onto a supply spool 31 in an alternative possible embodiment after being reeled off from supply spool 30 carpet yarn thread 5 first runs through heat setting apparatus 200 and only then passes through singe burner 100 or 100 39 of the type according.