Problems in Capacity Metering of Vertical Tank and its Countermeasures

A general description of "application - introduction -research" for capacity metering of vertical tank in China is given in this paper. It is pointed out that many problems in capacity metering of vertical tank exist such as low gauging accuracy, complecated gauging procedures, big errors, noncompliance of national standard temperatures with the internationally accepted temperature, and lack of the concept of simuta-neous capacity gauging for the whole tank tarm. An analysis on these problems shows that the gauging results are affected severely by such factors as the deformation of tank bottom plates, the variation of tank referential height, shell static pressui. produced by liquid stored, high liquid temperature as well as deformation and friction in the floating roof. The H + P gauging system developed in Tianjin Metering Technique Institute is introduced in the paper. The system is considered successful in continuous tracing for tank level, and the system represents a developing trend in capacity gauging for vertical tanks.