Abstract: Abstract:How to ensure the thermal insulating pipeline for steam pressure measurement without heat tracing to do not freeze in lowtemperature environment was researched. Using the Fourier heat conducting formula, the length of thermal insulating pipeline for steam pressure measurement was calculated. The heat transmits along the sampling pipe in the pipe axial direction. At the same time, the heat radiates out through the heat insulating layer in the radial direction, which causes the temperature of the sampling pipe to lower gradually. The heat released by temperature reducing of the sampling pipeline of the steam pressure transducer is equal to the heat radiated out through the heat insulating layer. Due to that the outdoor steam pressure measurement is widely used in project construction, to adopt the heat insulating method to ensure normal operation of the instrument and the pipeline without heat tracing is of greater significance. Obviously, the investment of this method is low, and the work amount of the construction is reduced.

Key words: Keywords:low temperature environment, thermal isolation, heat conductivity coefficient, Fourier equation, thickness of thermal insulating layer