Apparatus for heat treating a continuously moving web

An apparatus for heat-treating an elongated textile web, said apparatus comprising:

• a gas-pervious conveyor belt having a stretch defining a treatment path having an upstream end and a downstream end;
• means for feeding the web to said upstream end and for advancing said belt to advance said web toward said downstream end along said path;
• a plurality of upwardly directed lower slot nozzles underneath said stretch along said path, said lower nozzles being generally perpendicular to said path;
• a plurality of downwardly directed upper slot nozzles above said stretch along said path, said lower slot nozzles being transverse to at least some of said upper slot nozzles;
• means for feeding a hot gas alternately to said upper and lower nozzles;
• and
• an upper housing wall spaced above said stretch and formed of a plurality of panels formed in turn with said upper nozzles, the upper nozzles of some of said panels being oriented differently from the upper nozzles of the balance of said panels, said upper nozzles being directed at an angle to a perpendicular drawn from said stretch and including inner nozzles over the center of said path and outer nozzles over the edges of said path, said outer nozzles being directed outwardly.