| 摘要 |
An apparatus in a draught valve for mounting in a ventilation duct, where the draught valve consists of two separately spring-loaded (10,11) valve blade halves (7,8), which pivot on a shaft (9), whose ends are fixed in the duct walls. The draught valve blade halves are designed to take up a fully open position by the effect of airflow of relatively high speed. The invention is characterised by each spring (10,11) being designed to push its draught valve blade half to return to a partly open, predetermined start position, when an air flow of significantly lower speed than the above named flow passes through the duct. The draught valve blade halves are designed so that in the said start position they are diagonal to the airflow, and an adjustment device (3,4) is designed to work in conjunction with each draught valve blade half (7,8) to hold its draught valve blade half in the said start position under the effect of the springs (10,11). The said start position is adjustable by the said adjustment device (3,4) to set up each draught valve blade half in any required partly open start position depending on an operational parameter in the system of which the draught valve apparatus is part.<IMAGE> |
