The object of research is an element of equipment in a vibrating screen, which is an active working body in the form of a plate. The key element in the system of the flush purification unit is the vibrating screen. The basic design of the sieve does not allow the flush solution to be distributed evenly over the entire working surface. The concentration of drilling fluid in the central part of the equipment leads to premature abrasive wear and failure of the working element. Therefore, the structure of the vibrating screen needs to be improved in order to extend its service life. This task has been solved through the introduction of an active element to the structure for the redistribution of the solution through additional transverse vibrations. The use of such an active element is an important step for improving the quality and efficiency of the purification system, which could optimize production processes and reduce costs in industry. Taking into account transverse vibrations and calculating frequency parameters could help improve the design and use the vibrating screen more productively. An analysis of the frequencies of oscillations of the active element-plate for cleaning the flush liquid with a vibrating screen was performed and a comparison of the analytically obtained results with the simulation data using the finite element method in the COMSOL Multiphysics software was carried out. The results are the basis for designing vibrating screens, conducting experimental and industrial research, and testing the screens. Computer studies have confirmed the possibility of using the improved design of the vibrating screen. By comparing the results of the calculation and computer simulation, the error was determined to be within 5 %. The identified patterns could make it possible to select the plate oscillation frequencies depending on the known initial parameters, which would be useful for solving similar tasks.