| 摘要 |
An aperture cover assembly (7, fig.2) for mounting on an open aperture (2, fig.1) of a heating chamber 3 of a tunnel-oven 1 for heating work-pieces (5, fig.1) conveyed through the heating chamber. The aperture cover assembly is adapted to automatically open as a work-piece is conveyed towards the aperture cover assembly, to allow passage of the work-piece through the aperture cover assembly, and to automatically close after passage of the work-piece. The aperture cover may open in response to a first sensor 15 signalling the approach of the work-piece, and close in response to a second sensor 18 signalling the passing of the work-piece. Preferably, the first sensor is adapted to measure the width of the work-piece and to transmit the width to a processing device which controls a door actuator 11 to open at least one door 9 to form a minimum opening. The first sensor may comprise an array of photoelectric detectors adapted to monitor the width of the work-piece. The assembly is designed to minimise the energy loss from the oven by convection at the oven-ends. |
