SPECIFICS OF DIAGNOSTICS OF TECHNICAL CONDITION OF TRANSPORT AND TECHNOLOGICAL SYSTEM “MINING GAS PIPELINE – MINE WORKING”
Authors: Zaichenko Stefan , Seminskyi O.O. , Zhukova Natalia , Derevianko Denys , Shalenko Vadym 
Published: December 2022

The purpose. Study of the physical and mechanical processes that accompany the operational cycle of conveyor rollers with the aim of establishing the main factors that affect the resource and justifying the design of the seal to ensure the maximum period of operation and production costs.

Methodology. To achieve the goal, the regularities of the main processes accompanying the operational cycle of the conveyor roller, thermal expansion and cooling of the roller space - "breathing", heating of the roller from atmospheric effects, friction of the roller on the conveyor belt and in the bearings, have been established; a model of thermodynamic equilibrium of roller elements was created, which combines the main processes accompanying the operational cycle; uniform recommendations have been created that will allow to ensure the maximum period of operation and production costs of conveyor rollers.

Findings. According to the results of analytical studies of the main processes accompanying the operational cycle of the conveyor roller, thermal expansion and cooling of the roller space, significant heating of the roller space to 40ºС was established. The heating of the roller leads to a number of negative phenomena, among which it is possible to separate heating of the lubricant with loss of rheological properties, heating of seals with loss of tightness, heating of bearings to temperatures close to critical (90ºС). A change in the average temperature of the roller can lead to a significant change in pressure (14600 Pa) under conditions of complete tightness. None of the known seals that are used for conveyor rollers can withstand this sign-changing pressure drop. For labyrinth seals, when heated, the pressure is completely equalized to the atmospheric level, which creates a "breathing" effect. In the process of "breathing" a certain amount of water condenses from moist air, which can completely destroy any structure of the conveyor roller through electrochemical corrosion. The impossibility of sealing the space of the conveyor roller with known structures of labyrinth seals has been proven, which requires the development of new technical solutions for modernization.

Originality. A model of the thermodynamic equilibrium of roller elements has been created, which will combine the main processes accompanying the operational cycle. Which shows the linear dependence of the heating temperature change on the load, the rolling resistance of the bearing and the roller bearing.

Practical implications. The solution that will minimize the process of “breathing” of the roller is to isolate the space of seals and bearings from the inner space of the roller. To implement this solution, it is necessary to add an additional row of seals to each bearing on the opposite side from the outer one. Also, to reduce the effect of "breathing" of the roller due to sealing, it is appropriate to depressurize the space of the roller.

Keywords: conveyor, labyrinth seals, heating, rolling resistance, temperature.