introduced into the duct and the air is heated by a heater which is positioned in the air supply line leading to the nozzle the output of the heater is controlled by a temperature sensor which is positioned inside the stuffer box also the nozzle comprises two confronting sections which can be separated to facilitate yarn thread up and a valve is provided in the supply line to divert the heated air to an exhaust line when the nozzle is opened a second temperature sensor is positioned in the supply line and is operative when the nozzle is opened to regulate the output of the heater and avoid large fluctuations of its output in a further embodiment the heater is controlled by a circuit which stores the signal from the temperature sensor in the stuffer box and this stored signal is utilized to control the heater when the nozzle is opened application_number US 61207190 A description fig1 and 2 and the subsequent description are in part taken from ep a 256 448 and u s pat no 4 829 640 the disclosures of which are expressly incorporated herein by reference the texturing nozzle comprises two rectangular sections 1 and 2 with a stuffer box 3 positioned downstream thereof the texturing nozzle and the stuffer box 3 are divided along a longitudinal plane 21 the nozzle section 1 shown on the left of fig1 with the half of the stuffer box 3 attached thereto is mounted on the machine frame 6 the nozzle section 2 and its associated half of the stuffer box 3.