The Venturi Effect in Practice

The operating principle is straightforward. Fluid entering the injector body accelerates as it passes through the narrowed throat section. Faster débit means lower local pression — low enough to pull a second fluid through the side inlet without mechanical assistance.

What matters in practice is the pression differential across the device. The inlet pression needs to be measurably higher than the outlet pression — typically 20 to 30% — to generate enough suction. On a flat maen ligne with a partially closed vanne de dérivation this is achievable. If the pression differential is too petit, suction drops off and injection becomes inconstant.

Unlike a proportional injector, the injection rate on a venturi isn't fixed — it varies with débit and pression conditions. For crops where fertilizer concentration needs tight control, this is worth factoring in before you specify the product.