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An alternative method for determining the empirical coefficients of the Kunin-Yurchenko equation of pressing is proposed. This method consists in constructing a polynomial regression tertiary model of the dependence of the density on the pressing pressure with subsequent approximate calculation of the empirical coefficients. The application of the proposed method showed good agreement with the experimental results (correlation ratio is not less than 0.97). Comparing the data obtained by the proposed method and the data obtained by the well-known method of “three pressings”, the same accuracy was found for both metallic and non-metallic powder materials. When processing large data arrays, for example, in adaptive algorithms for controlling the pressing process, it is preferable to use the proposed method, since it takes into account the influence of all experimental data on the compacting process of powder materials in the operating pressure range.

A probabilistic mathematical model describing the deposition process in the layers of a precoat filter is proposed. The method for calculating the filtration process of superfine particles with an auxiliary precoat layer according to the proposed model allows the optimal modes of filtration devices and their design and operating parameters to be chosen.

The results of tests and improving Freon centrifugal refrigeration compressor having gas-dynamic bearings and cooling power up to 350 kW are reported. The problems relating to rotor balancing, start-stop durability of rotor and bearings, rotor dynamics, and the results of compressor tests in air and Freon are elucidated. The compressor was tested with two types of bearings: without and with goffered tapes. The best results were obtained with the second type. The potential for use of gas-dynamic bearings in centrifugal refrigeration compressors is confirmed.

The article shows ways of increasing the degree of purification of gases by electrostatic precipitators (ESР). Possible mechanical problems with the ESP should be addressed and optimization of high-voltage power units should be conducted first. Further, the impact of a range of parameters on the degree of gas cleaning and dust discharge from the ESP is illustrated. An example illustrates the influence of changing a number of ESP parameters at an operating power plant on dust emissions from the ESP.