Flow rate quality of new flat fan nozzles

Manufacturers of spraying nozzles have established manufacturing tolerances to guarantee the quality of their products. They control, among other things, the new nozzles’ flow rate by comparison with the nominal flow rate. When the deviation exceeds a set limit, the nozzles are rejected. A survey carried out among three manufacturers made it possible to determine the manufacturing tolerances and limits that manufacturers impose upon themselves. The flow rates of 1565 new nozzles collected on the market from these manufacturers were measured on a device developed for this study. Different statistical tests assessed the performances and characteristics of the products. The quality standards announced by the manufacturers were not checked for every nozzle. On average, 20% of the new nozzles exceeded the manufacturing tolerances. The average flow rate of the nozzle sets equalled the nominal flow rate. In practice, the probability distribution of the flow rate of new nozzles should be normal. The dispersion of the new nozzle flow rates was slightly higher than the theoretical one. The quality of the products differed from one manufacturer to another.