ASTM D2272 Oxidation Stability of Steam Turbine Oils by Rotating Pressure Vessel (RPVOT)
Steam turbines typically operate continuously, with long periods between servicing. If a steam turbine oil becomes oxidized, it may form varnish and sludge, potentially resulting in costly and unexpected shutdowns. The rate of oxidation normally increases with temperature, entrained air or water, and catalyzing metals such as copper. This test is used to estimate the oxidative stability of new steam turbine oils, and to predict the remaining life of service oils.
The test oil is combined with water and a copper coil in the test cell. The test cell is placed in a pressure chamber, pressurized with oxygen and brought to the test temperature. The test chamber is rotated (to mimic the operation of a turbine) and the pressure is followed. The amount of time it takes for the pressure to drop 175kPa (25.4 psi) is reported. As a special service to our clients, Petro-Lubricant Testing Laboratories also describes the pressure drop as "inductive", meaning that the pressure dropped rapidly, or "non-inductive" meaning that the pressure dropped gradually (i.e. there was no sharp pressure drop).