Saybolt universal viscometer

In the SI system, the theoretical unit of v is m2/s or the commonly used Stoke (St) where 1 St = 0.0001 m2/s = 100 cSt = 100 centiStoke. Similarly, 1 centiStoke = 1 cSt = 0.000001 m2/s = 0.01 Stoke = 0.01 st. The specific gravity of water at 20.2°C (68.4°F) is almost 1. The kinematic viscosity of water at 20.2°C (68.4°F) is for all practical purposes equal to 1 cSt. For a liquid, the kinematic viscosity will decrease with higher temperature. For a gas, the kinematic viscosity will increase with higher temperature. Another commonly used kinematic viscosity unit is Saybolt universal seconds (SUS), which is the efflux time required for 60 mL of petroleum product to flow through the calibrated orifice of a Saybolt universal viscometer, as described by ASTM-D88. Therefore, the relationship between dynamic viscosity and kinematic viscosity can be expressed as... 

Saybolt Universal Seconds (SUS) are used to measure viscosity. The efflux time is the SUS required for 60 mL of a petroleum product to flow through the calibrated orifice of a Saybolt Universal viscometer, under carefully controlled temperature and as prescribed by test method ASTM D 88. This method has largely been replaced by the kinematic viscosity method. SUS is also called the SSU number (Seconds Saybolt Universal) or SSF number (Saybolt Seconds Furol). 

Saybolt Universal viscosity the time, in seconds (Saybolt Universal Seconds, SUS), for 60 ml of fluid to flow through a capillary tube in a Saybolt Universal viscometer at a given temperature. 

This is measured as the time (in seconds) required for a sample to flow through the orifice of a Saybolt universal viscometer, according to the conditions specified in ASTM D88. Viscosities measured are expressed as, for example, Saybolt universal seconds (SUS), Saybolt seconds universal (SSU), or Saybolt universal viscosity (SUV), and are usually measured at both 100°F and 210°F. This is an outdated method, but as mentioned earlier, its memory lingers in the industry terminology. 

SAYBOLT UNIVERSAL VISCOSITY - A commercial measure of viscosity expressed as a time in seconds required for 60 mL of a fluid to flow through the orifice of the standard Saybolt universal viscometer at a given temperature under specific conditions used for the lighter petroleum products and lubrication oils. 

Liquid viscosity is usually measured by the amount of time it takes for a given volume of liquid to flow through an orifice. The Saybolt universal viscometer is the most widely used device in the United States for the determination of the viscosity of fuel oils and liquids. It should be stressed that Saybolt viscosities, which are expressed in Saybolt seconds SSU), are not even approximately proportional to absolute viscosities except in the range above 200 SSU hence, converting units fiom Saybolt seconds to other units requires the use of special conversion tables. As the... 

A number of arbitrary viscosity units have also been used. The most common has been the Saybolt Universal second (SUs) which is simply the time in seconds required for 60 mL of oil to empty out of the cup in a Saybolt viscometer through a carefully specified opening. Detailed conversion tables appear in ASTM D2161, approximation of kinematic viscosity V in mm /s(= cSt) can be made from the relation shown in equation 8 ... 

Orifice. Orifice viscometers, also called efflux or cup viscometers, are commonly used to measure and control flow properties in the manufacture, processing, and appHcation of inks, paints, adhesives, and lubricating oils. Their design answered the need for simple, easy-to-operate viscometers in areas where precision and accuracy are not particularly important. In these situations knowledge of a tme viscosity is uimecessary, and the efflux time of a fixed volume of Hquid is a sufficient indication of the fluidity of the material. Examples of orifice viscometers include the Ford, Zahn, and Shell cups used for paints and inks and the Saybolt Universal and Furol instmments used for oils (Table 5). 

The Saybolt Universal and Saybolt Furol viscometers are widely used in the United States and the Engler in Europe. In the United States, viscosities on the lighter fuel grades are determined using the Saybolt Universal instrument at 38°C (100°E) for the heaviest fuels the Saybolt Enrol viscometer is used at 50°C (122°E). Similarly, in Europe, the Engler viscometer is used at temperatures of 20°C (68°E), 50°C (122°E), and in some instances at 100°C (212°E). Use of these empirical procedures for fuel oils is being superseded by kinematic system (ASTM D396 BS 2869) specifications for fuel oils. 

SAYBOLT UNIVERSAL VISCOSITY. The efflux time in seconds (SUS) of 60 mL of sample flowing through a calibrated Universal onfice in a Saybolt viscometer under specified conditions. 

See also Saybolt Universal Viscosity and Viscometer (or Viscosimeter). 

Furol viscosity. The efflux time in seconds (SFS) of 60 mL of sample flowing through a calibrated Furol orifice in a Saybolt viscometer under specified conditions. Furol viscosity is approximately 1/10 of Saybolt Universal viscosity and is used for fuel oil and residual materials of relatively high viscosity. Furol is derived from the words fuel and road oils. 

Water is the primary viscosity standard with an accepted viscosity at 20C of 0.010019 poise. Hydrocarbon liquids such as hexane are less viscous. Molasses may have a viscosity of several hundred centistokes, while for a very heavy lubrication oil the viscosity may be 100 centistokes. There are many empirical methods for measuring viscosity. See Saybolt Universal Viscosity viscometer. 

In the test, the time for a fixed volume of liquid to flow under gravity through the capillary of a calibrated viscometer under a reproducible driving head and at a closely controlled temperature is measured in seconds. The kinematic viscosity is the product of the measured flow time and the calibration constant of the viscometer. Conversion of the kinematic viscosity in centistokes (cSt) at any temperature to Saybolt Universal viscosity in Saybolt Universal seconds (SUS) at the same temperature and for converting kinematic viscosity in centistokes at 122 and 210°F to Saybolt Furol viscosity in Saybolt Furol seconds (SFS) at the same temperatures (ASTM D-2161) is avaibale through formulae. 

Although it is considered a technical advantage to specify kinematic viscosity, the conventional viscometers are still in wide use and it may be convenient, or even necessary, to be able to convert viscosities from one system to another. Provision is made (ASTM D-2161) for the conversion of kinematic viscosity to Saybolt Universal and Furol viscosity and (in IP standards) for conversion to Redwood viscosity ... 

Saybolt Viscosity (SSU or Seconds Saybolt Universal) The time in seconds required to fill at 60-cm flask with an oil specimen preheated to 38, 54, or 99° C and draining through a standard orifice. The measurement is convertible to kinematic viscosity by the equation V = 0.00222 t — 1.83/f, where v = kinematic viscosity, cm /s and t = Saybolt seconds. Several ASTM tests (www.astm.org) make use of the Saybolt viscometer. (Paint and coating testing manual (Gardner-Sward handbook) MNL 17, 14th edn. ASTM, Conshohocken, PA, 1995)... 

Saybolt viscometer A type of instrument used to determine the viscosity of petroleum oils. It is based on the time in seconds for a given volume of oil to pass through an aperture at a controlled temperature and collect in a container with a volume of 60 millilitres. The Saybolt universal second is the unit used as a measure of the ldnemaUc viscosity. 

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