A disposable respiratory flow apparatus has a fixing tube. A front and a rear end of the fixing tube are respectively having a drainage section and a connecting section. Two pressure measuring holes are respectively formed on two ends of the connecting section. The connecting section is used to connect with a detachable mouth tube have a flow controlling element. The connecting section has two pressure draining holes being formed corresponding to the flow controlling element and the pressure measuring holes. In the present invention, the flow controlling element is placed in the detachable mouth tube, thus the specification of the flow controlling element may be selectable for more larger measurement ranges to get better measurement result.一種一次性差壓式呼吸流量裝置,設有一固定管,該固定管的前、後兩段分為一引流段與一銜接段,在該銜接段的前、後位置設有兩壓差測量孔,在該固定管的銜接段安裝可插拔的口銜管,在口銜管內設有一節流件,配合兩壓差測量孔的位置,在節流件的前、後設有兩環繞排列且與兩壓差測量孔對應的導壓孔,該節流件阻隔在兩排導壓孔之間;本發明將節流件形成在一次性使用的口銜管內,使得節流件的規格可隨不同的口銜管變動,能量測更大的測量範圍,適合精確量測各種體型使用者的呼吸流量等數據。10‧‧‧固定管111‧‧‧壓力測量孔121‧‧‧壓差測量孔15‧‧‧工作孔20‧‧‧口銜管21‧‧‧插管段211‧‧‧導壓孔22‧‧‧傾斜段23‧‧‧咬嘴段27‧‧‧凹凸構造28‧‧‧過濾層
