| 摘要 |
A fan assembly (1) comprises a fan housing (3) having a fluid inlet (5) and a fluid outlet (7), a fan-impeller (11) being disposed between the fluid inlet (5) and fluid outlet (7). The fan assembly (1) further comprises pressure sensor means (13) and (15) operative to measure the fluid pressure upstream and downstream of the fan-impeller (11). Control means is operative to process pressure measurements from the pressure sensor means to determine a pressure difference across the fan-impeller and to process the determined pressure difference according to an algorithm to calculate the current volume flow rate of fluid through the fan-impeller (11). The control means is also operative to compare the calculated current volume flow rate with a desired volume flow rate of fluid and, if necessary, to adjust the fan-impeller (11) speed such that the desired volume flow rate of fluid is achieved. |
