Performances of constant air volume valve of pressure independent with nozzle

According to the domestic and foreign relevant standards, designs a performance experiment device for the valve. The experiment results show that relative error of the air volume is within ±20% when the ratio of initial coordinate of the spool to the maximum one ranges from 50% to 75% and the pressure difference across the valve is in the range of 300 Pa to 800 Pa. Analyses the influence of structure parameters on performance, and makes some suggestion on improving and perfecting the valve design.