a short distance downstream of the plug outlet 34 a feed means 30 is arranged which is formed in the present embodiment by two opposite rolls the feed rolls are driven in opposite directions via a drive unit 31 the feed nozzle 1 and the crimping device 2 are controlled by a controller 32 to this end the controller 32 connects via a plurality of control lines to the fluid regulating means 10 the suction regulating means 21 the heating device 9 and the drive unit 31 in the embodiment of the apparatus according to the invention for carrying out the method of the invention as shown in fig1 a yarn path is shown for better illustrating the operation of the apparatus in the apparatus a conveying fluid made available by the source of pressure 11 is supplied to the feed nozzle 1 in a first step the fluid regulating means 10 permits adjusting preferably a conveying pressure under which the conveying medium is supplied to the fluid inlet 8 via supply line 33 before that the conveying fluid is heated by the heating device 9 from the fluid inlet 8 the conveying fluid enters the pressure chamber 7 and flows at a high velocity through the air inlet passageways 6 into the yarn channel 3 the conveying fluid entrains a yarn 28 that has been inserted into the yarn channel 3 and advances it.