This standard specifies the procedures for converting the reading of glass petroleum hydrometer (observed density) obtained at non-reference temperature into the density (density at 20℃) and volume correction factor at reference temperature.
This standard is applicable to crude oil, lubricating oil and other liquefied petrolatum products.
The reference temperature specified in this standard is 20℃.
The thermal expansion data of oil products used in Petroleum Measurement Tables in this standard are consistent with those in ISO 91-1.
Note: In the preparation, the thermal expansion coefficient adopted for reading correction of densimeter is the same as that in ISO 91-1, i.e. 23×10-6℃-1. The value is slightly lower than the conventional value (25× 10-6℃-1) referred in ISO 1768, but the coefficient difference has little influence on the correction results at the actual maximum temperature difference. If the Parties both consider that the effect of errors shall be considered, before looking up the table, deduct 0.000002ρt′(t-20) from the reading of densimeter, and ρt′ refers to the reading of glass densimeter and t refers to test temperature.
2 Normative References
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. Unless otherwise stated in the standard, the standards indicated all shall be the current valid standards.
GB/T 1884 Crude Petroleum and Liquid Petroleum Products - Laboratory Determination of Density - Hydrometer Method
ISO 91-1 Petroleum Measurement Tables Part 1: Tables Based on Reference Temperatures of 15℃ and 60 ㄈ.
ISO 1768 Glass Hydrometers - Conventional Value for the Thermal Cubic Expansion Coefficient (for Use in the Preparation of Measurement Tables for Liquids)
3 Definition
For the purpose of this standard, the following definitions apply.
