The article is devoted to devices for subsurface fertilization in the form of drip-air mixtures. A comparative analysis of spray mixers with centrifugal and jet nozzles has been carried out. The article presents the results of a study on the spray dependence on the ratio of air and liquid pressure with increasing fluid flow and steady air flow. It has been established that a spray mixer with a centrifugal nozzle gives a thinner spray cone is better in its operational qualities and will more fully meet the requirements for devices for intra-soil application of liquid fertilizers. In addition, it was determined that according to agrotechnical requirements, the average diameter of liquid droplets injected into the soil must be kept constant, and the flow rate must be changed, leaving the device speed and the compressor operating mode unchanged.

In order to identify the regularities of further increasing the efficiency of transport and technological machines, it is of interest to consider the issues of determining the impact of their design and technological parameters on the quality of running-in and the operability of fuel pumps. The article analyzes the influence of the initial operating modes and the lubricating medium on the quality of running-in and subsequent performance of high-pressure fuel pumps. On the basis of theoretical studies, equations were obtained to determine the unbalanced radial force acting on the plunger and fuel leaks in the plunger pair. These expressions make it possible to establish the dependence of the specific pressure in the plunger and barrel assembly both on the design and technological parameters of the pump.