| 摘要 |
A measuring device, for automatically measuring in situ and over a gas passage opening through which a gas flow passes, has a pressure difference gauge allowing the measurement of a pressure difference between the inside and the outside of the funnel mouth connected to the device after the latter is placed for measuring purposes over the opening, the value of the pressure difference thereafter being transferred into an electronic signal which controls the intensity of power supply to and, also if desired its running direction, of a control fan which is located in the throat cross section of the measuring device, one and the other in such a way, that after placing the funnel mouth over the opening while operating the device for measuring the gas delivery, each measured pressure difference is reduced down to zero at a fan speed and fan running direction which corresponds to the relevant gas delivery and its relevant direction of gas flow which flow rate values become instantly readable from a reading window which is connected to the measuring device; the device is easy to handle and may be made portable. |
