Abstract: A process and apparatus for producing multi filament yarn from polypropylene polymer. The process includes the steps of spinning an undrawn yarn using a spinnerette, and winding the undrawn yarn on a bobbin. Subsequently the undrawn yarn is unwound so that no twist is imparted to the yarn and the yarn is then drawn between godet rollers through a convection oven, the drawn yarn being wound on a bobbin.

Abstract: The present invention provides an oven comprising an elongate chamber with an inlet orifice at one end and an outlet orifice at the other end, via which a filament can pass through the chamber. Primary nozzles for use in introducing hot gas into the chamber are arranged, together with a gas outlet port, adjacent to the said one end of the chamber. Preferably the outlet port is nearer to the said one end than the primary nozzles. Secondary nozzles also for introducing hot gas into the chamber are arranged adjacent to the other end of the chamber. In use, hot gas is fed under pressure into the chamber via the primary and secondary nozzles against the direction of filament travel. Whilst the hot gas is fed under high pressure through the primary nozzles, the hot gas is fed at a relatively low pressure but high volume through the secondary nozzles. In this way the filament is heated all along its length in the chamber.