KINEMATIC VISCOSITY DEFINITION FREE

The duplicate test results should not differ by more than the values given below Material Report always the test temperature along with the results.

If this efflux time is less than 60s, select a viscometer of smaller capillary diameter and repeat the operation.Ĭ = Calibration constant of the viscometer in centistokes per second.Measure to the nearest 0.1 seconds the time required for the leading edge of the meniscus to pass from timing mark E to the tinting mark F.Remove the stopper in the tube N and L respectively and allow the sample to flow by gravity.It takes about 20 min at 38☌, 25 mm at 100☌ and 30 miii at 135☌.Allow the viscometer to remain in the constant temperature bath for a sufficient time to ensure that the sample reaches temperature equilibrium.The upper meniscus shall coincide with mark 0.Remove the excess sample above filling mark 0 by inserting the special pipette until its cork rests on top of the tube N and apply gentle suction until the air is drawn through.After allowing the sample to attain bath temperature and any air bubble to rise to the surface (Usually, about 20 to 30 mm is required), gently loosen the stopper allowing the sample to flow until it is approximately at the lower filling mark H and press back the stopper to arrest flow.Add more liquid, if necessary to bring the upper meniscus slightly above mark 0.Allow the sample to flow freely through capillary R, taking care that the liquid column remains unbroken until the lower mark H and then arrest its flow by closing the timing tube with a cork or rubber stopper in tube L.Pour sample through tube N to a point just above filling mark 0.Mount the BS U – Tube viscometer in the constant temperature bath keeping tube L vertical.G1 = acceleration of gravity at the calibrator laboratory G2 = acceleration of gravity at the testing laboratory If the visco meter is used at a location other than the calibrating laboratory the constant ‘C’ should be corrected for the difference in the acceleration of gravity ‘g’ at the two locations as followsĬ2 = Calibration constant in the testing laboratoryĬ1 = Calibration constant in the calibration laboratory.V =Viscosity in centistokes for the standard liquid Measure to within 0.5 seconds the time required for the leading edge of the meniscus to pass from the first timing mark to the second.Allow the charged viscometer to remain in the bath long enough to reach the main test temperature.Place the charged viscometer in the bath maintained at a temperature within 0.10 C.Charge the clean dry viscometer by pouring the known viscosity material.Any liquid of known viscosity may be used for calibration of viscometer.Stopwatch capable of being read up to 0.5 seconds.The thermometer of capacity 90˚ C and with an accuracy of 0.10 C.Provision shall be made for visibility of the viscometer and the thermometer.A suitable bath for immersion of viscometer so that the liquid reservoir or top of the capillary whichever is uppermost is at least 2 cm below the upper bath level.

KINEMATIC VISCOSITY DEFINITION FREE

The viscometer shall be made of clear borosilicate or other heat resistant glass free from visible defects.

B S U - Tube Modified Reverse Flow Viscometer.Kinematic viscosity is defined as the quotient of the absolute or dynamic viscosity divided by the density of the liquid both at the same temperature.

Kinematic viscosity definition