Some Problems in China's Capacity Calibration of Vertical Tank

There remain many problems in the JJG168-87 standard after it put into use over 10 years, which can not meet the current needs of the capacity calibration and meeting accuracy of vertical tank without revising in time. The problems existed in the standard are that the accuracy of capacity table is low, the optical measurement system is directly listed in the standard without any site comparison trial. At present, the buckling or settlement of tank bottom plate are the major factors impacting the metering accuracy, therefore, a corresponding metering method is extremely urgent need in order to revise the current standard. The tentative idea for the current standard is to classify the vertical tank as a metering tank and a storage tank, while the metering tank is classified as a trade metering tank and a non-trade tank. It is suggested that the two clauses of the users' application and on-site inspection (on the tank to be calibrated) before operation should be revised to the current standard during the calibration procedure for the vertical tank.