Venetian-blind type ventilator - has slats with upright edges extending clear of frame

摘要

The ventilator has a frame accommodating a number of parallel slats movable between the overlapping shut position and the open one. The slats have upright lengthwise edges and are operated together. The slats and upright edges extend clear of the frame, and can be secured to the frame near one of the lengthwise edges. There can be side plates fixed to the short edges, enclosing the frame in the shut position. The ventilator can be accommodated in a housing with openings at top and bottom, the frame being horizontal and directly above a box. One or more of the openings between frame and box is shut by a flap valve.