MONITORING OF A SEALED AND THERMALLY INSULATED VAT

摘要

The invention relates to a method for monitoring a sealed and thermally insulated vat (1) intended to hold a fuel gas that is liquefied at low temperature, in which a wall of the vat comprises a thermally insulated barrier (3) arranged between the sealing membrane and the bearing wall, the thermally insulated barrier comprising solid insulation materials and a gas phase maintained at a negative relative pressure, the method comprising: obtaining a diluted gas sample by collecting a sample of the gaseous phase at the negative relative pressure in the thermally insulated barrier through a collection tube (11) and by the addition of a controlled quantity of an inert gas to the gaseous phase to be collected or that has been collected, raising the pressure of the diluted gas sample to an operating pressure of a gas analyzer (25), and measuring a concentration of the fuel gas in the diluted gas sample with the gas analyzer.