The application of various types of evaporation plants for concentration of solutions was analyzed. It was noted that the most promising for thickening dairy products are film-type vacuum-evaporation units with mechanical compression of secondary steam. The heating chamber of the evaporator is made in the form of a vertical shell-and-tube heat exchanger with the supply of heating steam into the intertube space and with the downward movement of product solutions in the vertical boiling tubes. Based on the analysis of known studies on hydrodynamics and heat exchange of film processes (condensation, film heating and evaporation and steam separation), a conclusion was made about the lack of data for calculating pressure losses in the steam circuit of the evaporator with sufficient accuracy. To solve this problem, improved methods of calculating the hydraulic resistance of the intertube steam path of the heating chamber and the two-phase flow of the product film and secondary steam in evaporative boiling tubes have been developed using the published results of hydrodynamic resistance research. Pressure losses for the movement of secondary steam in the lower chamber of the evaporator include losses for acceleration of the steam released from the falling film of the product. It is shown that the hydraulic depression of the movement of steam in the intertube space of the heating chamber, depending on the type of scheme, can be from 2.3% to 77% compared to the working temperature pressure of the heating surfaces. The four-way flow scheme of the heating steam used in the design of the vacuum-evaporation unit ensures a reduction of hydraulic losses by up to 15%. A technical and economic analysis of the costs of operating a vacuum-evaporation unit with a productivity of 10 t/h of vaporized steam was performed, according to which the lowest reduced costs were established at a temperature drop of 5˚C on the compressor. The results of the research were used in the development of structures and the manufacture of vacuum-evaporation units with mechanical and mixed (mechanical and thermal) compression at PrJSC "Kalyniv Machine-Building Plant" (Kalynivka, Vinnytsia Region). 10 vacuum evaporation units with a capacity of 5 to 20 t/h of evaporated moisture were manufactured and put into operation.