Pneumatic transport device particularly for single-seed seed drill

In a pneumatic transport apparatus particularly for single-seed drills, comprising an inlet tube (10) into which the seeds are introduced one by one, an annular passage (13) of convergent form for air under pressure about the end of the inlet tube (10) and a tubular passage (14) whose one end communicates with said annular passage and whose other end is connected to a pneumatic transport tube (17);

• the improvement comprising downstream and at a small distance from the neck of the annular passage (13) of convergent form, a plurality of openings (18) communicating between the tubular passage (14) and the atmosphere and diverging downstream at an acute angle from the axis of said tubular passage (14), the total cross-sectional area of said openings (18) corresponding to about 1/2 to 1/3 of the cross-sectional area of said tubular passage (14), whereby the pressure is decreased downstream from said openings (18).