Throughflow treatment control.

摘要

A process in which material (20) is passed effectively continuously through a gaseous treatment chamber (10) by way of at least one open port (12) is improved by applying gas curtains across the material path to form externally adjacent the port a buffer zone (50) between the chamber interior and the surrounding atmosphere, which zone acts generally to balance the gaseous outflow otherwise occurring through the port. The buffer zone is preferably formed by and between two curtains serially spaced nearer to and further from the port, the curtains being respectively formed with gas drawn from without and within the zone. The zone is suitably sustained in varying conditions by control of curtain flow rate in response to a zone parameter such as temperature.