Demisting jets for bus windscreen

摘要

The demisting jets are positioned along the bottom edge of the upright windscreen and provide a curtain of demisting air upwards over the windscreen. A large cross-sectional area air duct (6) supplies the air from a supply duct (8). The air is transferred to a secondary duct (6), parallel to the first, by a control flap (15). The smaller secondary duct is provided with a series of apertures (20) feeding a narrow duct (7) in the top of which are the demisting jets (21). The effect of the three parallel ducts is to provide even pressure for all the demisting jets. The demisting jets are spatially arranged for optimum demisting effect. The relative cross-sectional areas of the three ducts are 100:40:10, while the relative cross-sections of the main apertures between the ducts are 100:50, with the apertures of the demisting jets each 1.5 % of that of the main duct.