The use of local exhaust ventilation systems continues to be the most reliable way to capture pollutants in the technological processes of various industries. The main purpose of the application of local exhaust ventilation systems is the effective capture of pollutants in the places of their formation. Improving the efficiency of local exhausts and, accordingly, reducing the load of general ventilation can be achieved through the use of air screens. For baths filled with liquids most often

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... activated on-board suction pumps that operate on the scheme of "jet-suction", which are structurally located on the same axis of the supply nozzle and slotted drain. According to this principle of operation, various activated extractors require air exchange in large volumes with significant energy consumption and at the same time with insufficiently high sanitary and hygienic indicators. In order to increase the efficiency of the local ventilation system, especially for tanks with large open surfaces, fundamentally new aerodynamic schemes are required, the feature of which is the formation of dynamic screens with inflow and rotation flows. On the basis of analytical research the basic possible variants of the device of the two-level air-jet screen of an industrial bath by drawing up balance equations for achievement of the maximum efficiency factor η are considered. The analysis of theories of interactions of inflow jets, suction flares and convective flows from liquid surfaces is carried out. The aerodynamic problem of a flat turbulent flow is considered, in which inflow jets interact with a 180 ° expansion, forming a two-level closed rotating system with concentrated flow, which is affected by convective flows with harmful substances from an industrial bath. The assumptions and calculations confirmed the fundamental possibility of using a system of two-level air-jet screens for large baths.