Ventilated double glazed window unit - has frame of double U=section with web rebate at centre flange and air holes in sill overhang and inner head

摘要

The double glazed window unit may be mounted on fixed or movable window frames (8), provides for both thermal and sound insulation together with convection type ventilation. The unit has a 'U' section frame (4) with a secondary flange (13) projecting at right angles from the outer face of one primary flange (11), and with an assymetric 'V' section web (9, 12). The step formed by the secondary flange (13) locates the frame in an existing frame rebate, the shorter inclined web leg (12) locating externally to mask the joint. A thick external pane (1) is bedded on seals (14) and bonded in the external angle. It rests on spacer blocks (15) above a filter (22) covered opening (2) in the sill overhang. The inner pane is fixed in the angle formed by the secondary flange, located by flange returns (18) and a channel section bedding seal (16). A hollow moulding (17) of one seal leg is removed at the head of the frame to provide a slotted air inlet (19).