| 摘要 |
The invention solves the problem of elimination of rigid dams in the air flow duct and makes the measurement conditions more natural. A pneumotachograph comprises an external tube (1) having a first, bigger diameter, and on the inside thereof at least one internal tube (2) of smaller diameter situated preferably concentrically with the external tube (1). The external tube (1) of bigger diameter is shorter than the latter (1) tube whereas the orifice of the external tube (1) of bigger diameter has a closure (A) between its edge and the internal tube (2) of smaller diameter so that the air flow duct is the internal tube (2) of smaller diameter. At least one measuring orifice (B) is situated within the measuring area comprising the external wall of the tube (2) of smaller diameter, the internal wall of the closure (A) of the tube (1) of bigger diameter, the internal wall of the tube (1) of bigger diameter and the space confined within the mentioned walls. |
