Measurement of the static evaporation rate of welded insulated cylinders using grey prediction

To solve the long-time consuming and wasting in measurement of the static evaporation rate of welded cryogenic insulated high vacuum gas cylinders, the evaporation rates of liquid nitrogen in the cylinders were measured in the lab by weighting. Grey model GM(1,1) is used to predict the evaporation rates based on the measuring data. The studies show that evaporation quality within 72 hours can be predicted based on the data tested within 60 hours by GM(1,1) model. The relative error of evaporation rates between prediction value and measured value is less than 5%. By applying this prediction method in the automatic measuring system of evaporation rate, the testing efficiency of the insulated cylinders is improved, the turning over rate of the cylinders is increased and the cryogenic liquid consumption in the inspection is lowered.