To provide a pressure loss measuring method for continuously measuring pressure losses of an air permeable sheet and its measuring apparatus.
In the pressure loss measuring method, by correcting points that it has been impossible to perform air suction at a predetermined passage speed and that the structure of the air permeable sheet continuously changes, which are problematic points in the case that the air permeable sheet is continuously moving, true pressure losses are derived on the basis of the relation between the pressure losses and air passage speeds with the air permeable sheet halted in movement. The pressure loss measuring apparatus is provided with an electronic computer with a first operation part for deriving the relation between the air passage speeds and the pressure losses with the air permeable sheet halted in movement, a second operation part for deriving the relation between the air passage speeds and the pressure losses when the air permeable sheet is moving, and a third operation part for deriving the true pressure losses at the predetermined air passage speed.
NAKAGAWA NOBORU
NAKAI JUN
