The reason why petroleum product determination methods are divided into closed cup method and open cup method is mainly determined by the nature and use conditions of petroleum products. Generally, the closed flash point tester is mostly used for light petroleum products with large evaporation type, such as transformer oil, fuel oil, solvent oil, etc. Since the measurement conditions are similar to the actual storage and use conditions of light oil products, it can be used as a fire safety control The basis of the indicator. The open flash point tester is mainly used for lubricating oil and heavy petroleum products. Because when the open flash point is measured, the vapor formed by heating petroleum products continuously diffuses to the surrounding air, making the measured flash point higher. For most lubricating oils and heavy oils, especially when used in non-closed parts or under low temperature conditions, even a very small amount of light blends will evaporate during use and will not cause a fire or The risk of explosion, so these products are measured with an open flash point tester.
One. Different definitions
1. Open flash point: The result measured with a prescribed open flash point tester is called the open flash point, expressed in °C.
2. Closed flash point: In a stable air environment, the lowest temperature at which the vapor generated from the flammable liquid or solid surface is flashed under the action of the test flame.
Two, different uses
1. Open flash point: mostly used in lubricating oil and heavy petroleum products. Because when measuring with the open cup method, the vapor formed by heating petroleum products is constantly flowing.
2. Closed flash point: used for light petroleum products with high evaporative properties, such as solvent naphtha, kerosene, etc. Since the measurement conditions are similar to the actual storage and use conditions of light oil products, it can be used as a basis for fire safety control indicators.
Three, the measurement method is different
1. Open flash point: The test oil is heated in an open cup, and the vaporized oil gas can diffuse freely into the air, and it is not easy to accumulate to the concentration of the lower explosive limit.
2. Closed flash point: The test oil is heated in a closed oil cup, and the lid is opened only at the moment of ignition.
