JUNTA PARA GASES DE INSTALACIONES DE TRATAMIENTO TERMICO DE PASO CONTINUO CON ATMOSFERA GASEOSA PROTECTORA

Junta aerodinámica de instalaciones de tratamiento térmico de paso continuo con atmósfera gaseosa protectora con toberas ranuradas que limitan con una sección transversal de abertura a obturar de la instalación de tratamiento térmico de paso continuo y orientadas hacia una cinta metálica continua (3), caracterizada porque a cada lado de la cinta metálica (3) le están asignadas dos toberas ranuradas separadas (13, 14; 15, 16) dispuestas a distancia una tras otra en dirección de paso de la cinta metálica (3) y que generan respectivamente un chorro de gas orientado perpendicularmente a la cinta metálica (3) u orientado hacia la cinta metálica (3) formando un ángulo y separado del otro, solicitándose con aire las toberas ranuradas (14, 16) orientadas hacia el lado de la atmósfera y con gas protector las toberas ranuradas (13, 15) orientadas hacia el lado de la instalación de tratamiento térmico de paso continuo. An aerodynamic seal for a continuous heat treatment furnace which contains a protective atmosphere, and through which a metal strip moves in a given direction is disclosed. The seal is adjacent a passage through which the strip moves through a wall of the furnace, and comprises two slit nozzles above the strip and two slit nozzles below the strip, and inlets for causing a jet of gas to flow through each of the slit nozzles. The slit nozzles are so positioned that gas flowing normal to the strip through the two nozzles above the strip will strike the strip in two lines which are separated from one another in the given direction, and gas flowing normal to the strip through the two nozzles below the strip will strike the strip in two lines which are separated from one another in the given direction. The slit nozzles are operable to direct jets of gas toward the strip in a direction that is either normal to the strip or diverges from normal away from a jet of gas from the other of the nozzles on the same side of the strip. The seal causes a flow which consists of a protective gas through the two nozzles which are closer to the furnace, and causes air to flow through the two nozzles which are farther from the furnace.