The Direct Injection Technique for Preparing the Spray Mix - A Method for Reducing Safety and Hygiene Problems in Plant Protection?1

In the past, industry and research institutes have produced a number of technical proposals to improve sprayer technique, and development in this area has been very successful. The «closed sprayer-system>>, the pesticide flushing system, flow regulation systems and updated stirring arrangement are examples of many different practicable improvements. A completely new approach to improving application technique is the « direct injection of pesticides >>: contrary to normal practice the tank of the sprayer is filled with pure water only. The pesticide is introduced in concentrate form into a separate tank and injected into the water flow produced by the equipment pump during the application process. The advantages of this technique include no direct handling of the active substance concentrate; no problems with liquid-stirring; no pesticide residues. A commercial sprayer equipped with a metering device prototype and a newly developed constant pressure fitting is described as an illustrative example of prospective design of a « direct-injection >> system. A number of other technical possibilities exist for putting this method into practice. The advantages of this technique have to be paid by an additional capital outlay but they offer the chance to reduce safety and hygiene problems in chemical plant protection.