Purpose: to determine the kinematic viscosity of the oil
Materials and reagents
Utensils: cylinders, glass
Equipment:
Viscometer VPZh-2 ISO 3104- 84
Thermometer DSTU 215-83
Stopwatch DSTU 5072-82
Filter paper DSTU 12026-86
Distilled water DSTU 6709-82
Viscometer type VU DSTU 1532-82
Methods of laboratory work
Determining the viscosity of oil or petroleum products in a capillary viscometer is to measure the leakage time of a certain volume of the tested petroleum product under the influence of gravity. The test is performed at a temperature of 20 ° C. A viscometer with such a capillary diameter is selected for analysis so that the oil leakage time is not less than 200 s. In laboratory practice, the most common are Pinkevych viscometers type VPZHT-4 and VPZHT-2 (Fig. 1).
A clean dry viscometer is filled with petroleum product. To do this, put a rubber tube on the discharge tube 3. Next, pinching the knee 2 with your finger and turning the viscometer, lower the knee 1 into the vessel with oil and suck the oil or oil product with a rubber bulb, water jet pump or otherwise to the mark M2, making sure that the sample does not form air bubbles. Remove the viscometer from the vessel and quickly return to normal. Remove the excess oil from the outside of the end of the knee 1 and put a rubber tube on its end. The viscometer is installed in a thermostat (bath heated to a certain temperature) so that the expansion 4 was below the water level. After holding in the thermostat for at least 15 minutes, the oil or oil product is sucked into the knee 1, up to approximately 5–10 mm of the height of the M1 mark.
Connect elbow 1 to the atmosphere and determine the time of movement of the oil meniscus or oil product from the mark M1 to M2 (with an error of not more than 0.2 s). If the results of three consecutive measurements do not differ by more than 0.2%, the kinematic viscosity ν, mm2 / s, is calculated as the arithmetic mean of the formula
γ = С ∙ τ
where C is a constant viscometer, mm2 / s (given in the certificate of inspection);
τ is the arithmetic mean of the oil product in the viscometer, p.
The permissible differences of successive determinations of kinematic viscosity from the arithmetic mean should not exceed the values ​​given in table.

Measurement temperature, ° С –60 ÷ 30 –30 ÷ 15 15 ÷ 150
Permissible discrepancy,% ± 2.5 ± 1.5 ± 1.2

Fig.1. Pinkevich’s viscometers:
a – type VPZhT-4; b– type VPZhT-2:
1, 2 – knee, 3 – outlet tube; 4 – expansion of the capillary tube

 

 

 

Video determination of kinematic viscosity
Processing of the obtained results
The protocol of laboratory work should contain: basic definitions and general provisions; description of the laboratory installation
Petroleum viscosity parameters.

Indicator Diesel fuel
Kinematic viscosity (mm2 / s)
At 0° C 7.5
At 20 ° C 3.8
At 40 ° C 2.5

Control questions
What are the requirements for diesel fuel?
How does viscosity change with temperature and what characterizes it?
What is kinematic viscosity and how is it determined?
What is the viscosity index and how is it determined?