N. P. Starostin, M. A. Vasilieva

SUBSTANTIATION OF TECHNOLOGICAL OPERATIONS OF WELDING A SADDLE BRANCH TO POLYETHYLENE PIPES AT TEMPERATURES BELOW AVAILABLE

Additional branches for gas supply systems are generally installed during the completion
of the construction of a gas pipeline, often falling in the autumn or winter time, when the air temperature is below the maximum allowable for welding polyethylene pipes. At ambient temperatures below minus 15 °С, it is recommended to weld polyethylene pipes under a shelter, where the temperature is maintained in the permissible temperature range.

The paper proposes a mathematical model for the thermal process of welding a saddle branch to a polyethylene pipe taking into account the heat of phase transition. The corresponding three-dimensional non-linear heat equation is solved by the finite element method. As an example, calculations were made for a PE 100 SDR 11 polyethylene pipe and a 100/63 saddle tap. Comparison of the calculated and experimental temperature data establishes the adequacy of the proposed mathematical model to the actual thermal process of welding a saddle branch to a polyethylene pipe.

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