| 摘要 |
An airflow volume sensing means for determining the flow rate through a fan includes a curved inlet cone with a pressure sensor at the minimum diameter of the cone, wherein the flow volume sensing means is particularly suited for FC centrifugal fans (centrifugal fans with forward curved fan blades). With an FC fan, the minimum diameter of the inlet cone's interior surface is adjacent the fan wheel, and the static pressure there is at a minimum value. A predetermined relationship between the static gage pressure at that point and the volume flow rate through the fan is applied regardless of variables such as fan speed, fan housing geometry, supply air duct configurations, return air duct configurations, location of various heat exchangers or filters, etc. In some embodiments, a single pressure sensor senses an average of a plurality of pressure taps, wherein each tap is at approximately the same minimum pressure. |
