Comparative Analysis of Automatic Shut-off Valves for Dosing Plant Protection Products

In installations for the production of mineral fertilizers, most of the units and parts are in contact with aggressive environments. This significantly reduces the service life of the equipment and in a certain way affects the technological process of production, reducing the quality of the resulting product. In addition, even in the absence of the influence of chemical elements, such installations have shut-off valves and cut-off devices that must meet a number of requirements in conditions of changing properties of the dosed liquids. Often, it is not possible to completely solve the problem of accurate dosing even when using well-known expensive high-quality materials, such as stainless steel. Therefore, the search for optimal solutions in the design and materials for shut-off valves used in agricultural production is still a fairly urgent task. The purpose of the study is to increase the productivity of the plant protection products (PPP) dosing unit by optimizing the parameters of the used shut-off devices. The results of the experimental studies showed that the gate valve with an electric drive does not meet the requirements for installations for the production of mineral fertilizers, due to the discrepancy in speed characteristics. Indirect acting valves have disadvantages when working in aggressive environments, since they do not provide reliable locking of solutions with a density greater than one. In addition, they have sealing parts that react with chemically active substances. Direct acting valves are more adapted to changes in the density of solutions, but the materials from which they are made are most often not chemically resistant. The article presents data from experimental studies of shut-off valves for dosing plant protection products, and an analysis of its tests is given.