![]() It is much easier to move a thin fluid (low viscosity) than a thick fluid (high viscosity). For instance, the viscosity of the fluid is important in sizing pumps, to know how hard the pump will have to work to move the fluid. Viscosity is also important in sizing pumps or heat exchangers. Viscosity is used to determine concentration of polymer quenchants. Confirmation tests with flashpoint or other tests can confirm oxidation or contamination. In oil quenchants, changes in the viscosity can indicate oxidation, or the presence of contamination with a lighter or heavier fluid. Even minor differences in temperature, such as the difference between 100☏ (37.8☌) and 40☌ (104☏) results in typically a 10 percent difference in viscosity. Temperature during measurement must be controlled very accurately, generally to less than ± 0.1☌. This time is dependent on the tube used (capillary size) and the temperature. The time that it takes to drain through a specific volume is the viscosity. After the sample is at temperature, it is pulled by suction to the measurement section. In the viscosity test, the fluid is placed in a specially designed glassware tube (Figure 1) and allowed to equilibrate at the desired temperature. Where μ is the dynamic viscosity, ρ is the density of the fluid, and ν is the kinematic viscosity. Kinematic viscosity is the ratio of dynamic viscosity to density: The (metric) units are g/(cm-s) or centipoise. Dynamic viscosity, or absolute viscosity, is a measure of the internal resistance of the fluid to motion. There are two types of viscosity - dynamic viscosity and kinematic viscosity. Typically, 100☏ and 210☏ are used for kinematic viscosity measurements in English units, and 40☌ and 100☌ are used for viscosity measurements using the metric system. If the viscosity is measured using the metric system, then viscosity is reported in centistokes, or cSt. If the temperature is measured in English units, then the units for viscosity are Saybolt Universal Seconds (SUS). Viscosity is a measure of a fluid’s resistance to flow at a given temperature. Viscosity and the viscosity index are terms that are applied not only to quenchants, but also to many other areas in machining, lubrication, and tribology. ![]() At the end of 1999, China lubriant website was set up, and the IDN is n this column, we will discuss the viscosity and viscosity index. In 2000, we published weekly electronic magazine which was welcomed by insiders. In 2002, we pioneered the mobile device-"Lube Expert " which won the certification from Shanghai Hi-tech Achievements Transformation Project. In 2006, we promoted the e-mail version of which drew great attention in the circle. Until 2011, we had been consecutively appointed as the only media supporter of the China International Lubricants and Technology Exhibition. Timeline In 2012, we designed and pioneered the English and Chinese bilingual app Viscosity Calculator Tool on the basis of mobile devices Android and IOS. About us Since 1999, have gathered lube industry stakeholders from all over the china to discuss regional and global issues which impact on our industry.Over the years, we have been playing an unique role in the lubricants industry in the Asia-Pacific is your B2B multimedia partner in china.
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