Method and apparatus for determining the solid fraction of a stored cryogenic refrigeration system

摘要

In the method of the invention, an unknown mass fraction (F) of solid cryogen in a stored cryogenic refrigeration system is determined. The method includes the steps of adding mass (T) of a trace substance which is soluble in the liquid phase of the system. The total mass amount (M) of the cryogen in the system is determined at the time of charging the system. The initial mass concentration (CI) of the trace substance is determined by dividing (T) by (M). During operation of the stored cryogenic refrigeration system, a small sample of the liquid phase cryogen is extracted from the system. The sample is analyzed to determine the new concentration (CN) of the trace substance in the sample. The new concentration (CN) of the sample is dependent on the amount of solid cryogen which has been produced in the system. Thereafter, the mass fraction (F) of solid cryogen in the system is determined by solving the equation: F=1-(CI/CN)