GB/T 265-1988 English PDF (GB/T265-1988)

GB/T 265-1988: Petroleum products. Determination of kinematic viscosity and calculation of dynamic viscosity
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GB/T 265-1988
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC 665.52/.59:532.13
E 30
GB/T 265-88
Replacing GB 265-83
Petroleum products - Determination of kinematic
viscosity and calculation of dynamic viscosity
ISSUED ON: APRIL 29, 1988
IMPLEMENTED ON: APRIL 01, 1989
Issued by: National Bureau of Standards
Table of Contents
1 Summary of methods ... 3 
2 Instruments and materials ... 3 
3 Reagents ... 5 
4 Preparation ... 6 
5 Test procedure ... 7 
6 Calculation ... 8 
7 Precision ... 10 
8 Reports ... 10 
Appendix A (Informative) ... 11 
Additional information ... 14 
Petroleum products - Determination of kinematic
viscosity and calculation of dynamic viscosity
This method is suitable for measuring the kinematic viscosity of liquid petroleum
products (referring to Newtonian liquid), in the unit of m2/s. However, during
practical use, it is usually in the unit of mm2/s. The dynamic viscosity can be
obtained, through multiplying the measured kinematic viscosity BY the density
of the liquid.
Note: For the liquid which is measured by this method, it is considered that the ratio of
the shear stress to the shear rate is a constant, that is, the viscosity has nothing to do
with the shear stress and the shear rate. This liquid is called a Newtonian liquid.
1 Summary of methods
This method is, at a constant temperature, to measure the time for a certain
volume of liquid, which flows through a calibrated glass capillary viscometer,
under gravity. The product of the capillary constant of the viscometer multiplied
by the flow time, is the kinematic viscosity of the measured liquid, at that
temperature. At temperature t, the kinematic viscosity is represented by the
symbol vt.
The product of the kinematic viscosity, at this temperature, multiplied by the
density of the liquid, at the same temperature, is the dynamic viscosity of the
liquid. The dynamic viscosity at temperature t is represented by the symbol ηt.
2 Instruments and materials
2.1 Apparatus
2.1.1 Viscometer:
2.1.1.1 The glass capillary viscometer shall meet the requirements of SH/T
0173 "Technical condition for glass capillary viscometer". It is also allowed to
use an automatic viscometer, which has the same accuracy.
2.1.1.2 A set of capillary viscometers: The capillary inner diameter is 0.4, 0.6,
UDC 665.52/.59
:532.13
GB/T 265-88
Replacing GB 265-83
Table 1 -- Constant temperature bath liquid used at different
temperatures
Note: It is better to add antioxidant additives to the mineral oil in the constant
temperature bath, to delay oxidation AND prolong the use time.
4 Preparation
4.1 When the specimen contains water or mechanical impurities, it must be
dehydrated, before the test; AND filtered by filter paper, to remove the
mechanical impurities.
For lubricating oil of high viscosity, it may use a porcelain funnel. It may use a
water flow pump or other vacuum pumps for suction filtration; OR otherwise, it
can be dehydrated and filtered, after heating to a temperature of 50 ~ 100 °C.
4.2 Before measuring the viscosity of the specimen, the viscometer must be
washed by solvent oil or petroleum ether. If the viscometer is stained, it shall be
washed by chromic acid lotion, water, distilled water or 95% ethanol. THEN, it
is put in an oven to dry, OR blow dry by hot air, which had been filtered through
cotton.
4.3 When measuring the kinematic viscosity, load the specimen into a clean
and dry capillary viscometer, which has an inner diameter that meets the
requirements. Before loading the specimen, put the rubber tube on the branch
tube 7. Use finger to block the opening of the tube body 6. At the same time,
turn the viscometer upside down. Then, insert the tube body 1 into the container,
which contains the specimen. At this time, use a rubber ball, a water flow pump
or other vacuum pump to suck the liquid to the marking line b. Meanwhile, be
careful not to cause bubbles and cracks, in the liquid in the tube body 1, as well
as the expansion parts 2 and 3. When the liquid level reaches the marking line
b, lift the viscometer from the container; quickly restore its normal state. At the
same time, wipe off the excess specimen, from the outer wall of the tube end
of the tube body 1. Remove the rubber tube from the branch tube 7. Sleeve it
over the tube body 1.
Table 2 -- Constant temperature time of viscometer in constant
temperature bath
5.2 Use the rubber tube, which is sleeved on the opening of the tube body 1 of
the capillary viscometer, to suck the specimen into the expansion part 3. Make
the specimen liquid level slightly higher than the marking line α. Be careful not
to let the capillary and the liquid in the expansion part 3 produce bubbles or
cracks.
5.3 At this time, observe the flow of the specimen in the tube. When the liquid
level just reaches the marking line α, start the stopwatch. When the liquid level
just reaches the marking line b, stop the stopwatch.
When the liquid level of the specimen flows in the expansion part 3, note that
the liquid, which is stirred in the constant temperature bath, shall be kept at
constant temperature; meanwhile there shall be no bubbles in the expansion
part.
5.4 For the flow time which is recorded by a stopwatch, it shall make at least
four repeated measurements. The difference between each flow time and its
arithmetic mean, shall meet the following requirements: When measuring the
viscosity at a temperature of 100 ~ 15 °C, this difference shall not exceed ± 0.5%
of the arithmetic mean; when measuring the viscosity at a temperature below
15 ~ -30°C, the difference shall not exceed ± 1.5% of the arithmetic mean; when
measuring the viscosity at a temperature below -30°C, the difference shall not
exceed ± 2.5% of the arithmetic mean.
Then, take the arithmetic mean of not less than three flow times, as the average
flow time of the specimen.
6 Calculation
6.1 At temperature t, the kinematic viscosity vt (mm2/s) of the specimen is
calculated according to formula (2):
Where:
c - Viscometer's constant, mm2/ s2;
τt - The average flow time of the specimen, s.
Example: The viscometer's constant is 0.4780 mm2/s2, the flow time of the
specimen at 50°C is 318.0, 322.4, 322.6, 321.0 s, so the arithmetic mean of the
flow time is as follows:
The allowable difference between each flow time and the average flow time is
as follows:
Because the difference between 318.0 s and the average flow time has
exceeded 1.6 s, it shall discard this reading. When calculating the average flow
time, it only uses the observation readings at 322.4, 322.6, 321.0 s; the
difference between them and the arithmetic mean does not exceed 1.6 s.
Thereby, the average flow time is:
The measurement result of the kinematic viscosity of specimen is as follows:
6.2 At temperature t, the dynamic viscosity ηt of the specimen is calculated as
follows:
6.2.1 According to GB/T 1884 "Petroleum and liquid petroleum product -
Determination of density - Hydrometer method" and GB/T 1885 "Petroleum
measurement tables", measure the density ρt of the specimen (g/cm3), at
temperature t.
6.2.2 At temperature t, the dynamic viscosity ηt (mPa•s) of the specimen is
calculated according to formula (3):
Where:
vt - The kinematic viscosity of the specimen, at temperature t, mm2/s;
GB/T 265-1988
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC 665.52/.59:532.13
E 30
GB/T 265-88
Replacing GB 265-83
Petroleum products - Determination of kinematic
viscosity and calculation of dynamic viscosity
ISSUED ON: APRIL 29, 1988
IMPLEMENTED ON: APRIL 01, 1989
Issued by: National Bureau of Standards
Table of Contents
1 Summary of methods ... 3 
2 Instruments and materials ... 3 
3 Reagents ... 5 
4 Preparation ... 6 
5 Test procedure ... 7 
6 Calculation ... 8 
7 Precision ... 10 
8 Reports ... 10 
Appendix A (Informative) ... 11 
Additional information ... 14 
Petroleum products - Determination of kinematic
viscosity and calculation of dynamic viscosity
This method is suitable for measuring the kinematic viscosity of liquid petroleum
products (referring to Newtonian liquid), in the unit of m2/s. However, during
practical use, it is usually in the unit of mm2/s. The dynamic viscosity can be
obtained, through multiplying the measured kinematic viscosity BY the density
of the liquid.
Note: For the liquid which is measured by this method, it is considered that the ratio of
the shear stress to the shear rate is a constant, that is, the viscosity has nothing to do
with the shear stress and the shear rate. This liquid is called a Newtonian liquid.
1 Summary of methods
This method is, at a constant temperature, to measure the time for a certain
volume of liquid, which flows through a calibrated glass capillary viscometer,
under gravity. The product of the capillary constant of the viscometer multiplied
by the flow time, is the kinematic viscosity of the measured liquid, at that
temperature. At temperature t, the kinematic viscosity is represented by the
symbol vt.
The product of the kinematic viscosity, at this temperature, multiplied by the
density of the liquid, at the same temperature, is the dynamic viscosity of the
liquid. The dynamic viscosity at temperature t is represented by the symbol ηt.
2 Instruments and materials
2.1 Apparatus
2.1.1 Viscometer:
2.1.1.1 The glass capillary viscometer shall meet the requirements of SH/T
0173 "Technical condition for glass capillary viscometer". It is also allowed to
use an automatic viscometer, which has the same accuracy.
2.1.1.2 A set of capillary viscometers: The capillary inner diameter is 0.4, 0.6,
UDC 665.52/.59
:532.13
GB/T 265-88
Replacing GB 265-83
Table 1 -- Constant temperature bath liquid used at different
temperatures
Note: It is better to add antioxidant additives to the mineral oil in the constant
temperature bath, to delay oxidation AND prolong the use time.
4 Preparation
4.1 When the specimen contains water or mechanical impurities, it must be
dehydrated, before the test; AND filtered by filter paper, to remove the
mechanical impurities.
For lubricating oil of high viscosity, it may use a porcelain funnel. It may use a
water flow pump or other vacuum pumps for suction filtration; OR otherwise, it
can be dehydrated and filtered, after heating to a temperature of 50 ~ 100 °C.
4.2 Before measuring the viscosity of the specimen, the viscometer must be
washed by solvent oil or petroleum ether. If the viscometer is stained, it shall be
washed by chromic acid lotion, water, distilled water or 95% ethanol. THEN, it
is put in an oven to dry, OR blow dry by hot air, which had been filtered through
cotton.
4.3 When measuring the kinematic viscosity, load the specimen into a clean
and dry capillary viscometer, which has an inner diameter that meets the
requirements. Before loading the specimen, put the rubber tube on the branch
tube 7. Use finger to block the opening of the tube body 6. At the same time,
turn the viscometer upside down. Then, insert the tube body 1 into the container,
which contains the specimen. At this time, use a rubber ball, a water flow pump
or other vacuum pump to suck the liquid to the marking line b. Meanwhile, be
careful not to cause bubbles and cracks, in the liquid in the tube body 1, as well
as the expansion parts 2 and 3. When the liquid level reaches the marking line
b, lift the viscometer from the container; quickly restore its normal state. At the
same time, wipe off the excess specimen, from the outer wall of the tube end
of the tube body 1. Remove the rubber tube from the branch tube 7. Sleeve it
over the tube body 1.
Table 2 -- Constant temperature time of viscometer in constant
temperature bath
5.2 Use the rubber tube, which is sleeved on the opening of the tube body 1 of
the capillary viscometer, to suck the specimen into the expansion part 3. Make
the specimen liquid level slightly higher than the marking line α. Be careful not
to let the capillary and the liquid in the expansion part 3 produce bubbles or
cracks.
5.3 At this time, observe the flow of the specimen in the tube. When the liquid
level just reaches the marking line α, start the stopwatch. When the liquid level
just reaches the marking line b, stop the stopwatch.
When the liquid level of the specimen flows in the expansion part 3, note that
the liquid, which is stirred in the constant temperature bath, shall be kept at
constant temperature; meanwhile there shall be no bubbles in the expansion
part.
5.4 For the flow time which is recorded by a stopwatch, it shall make at least
four repeated measurements. The difference between each flow time and its
arithmetic mean, shall meet the following requirements: When measuring the
viscosity at a temperature of 100 ~ 15 °C, this difference shall not exceed ± 0.5%
of the arithmetic mean; when measuring the viscosity at a temperature below
15 ~ -30°C, the difference shall not exceed ± 1.5% of the arithmetic mean; when
measuring the viscosity at a temperature below -30°C, the difference shall not
exceed ± 2.5% of the arithmetic mean.
Then, take the arithmetic mean of not less than three flow times, as the average
flow time of the specimen.
6 Calculation
6.1 At temperature t, the kinematic viscosity vt (mm2/s) of the specimen is
calculated according to formula (2):
Where:
c - Viscometer's constant, mm2/ s2;
τt - The average flow time of the specimen, s.
Example: The viscometer's constant is 0.4780 mm2/s2, the flow time of the
specimen at 50°C is 318.0, 322.4, 322.6, 321.0 s, so the arithmetic mean of the
flow time is as follows:
The allowable difference between each flow time and the average flow time is
as follows:
Because the difference between 318.0 s and the average flow time has
exceeded 1.6 s, it shall discard this reading. When calculating the average ...