NB/SH/T 0894-2015 Determination of shear stability of polymer-containing oils by ultrasonic method

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Card type: Test method

1. Method number / full title / English title / replacement relationship

• Standard number: NB/SH/T 0894—2015
• Chinese full title: Determination of shear stability of polymer-containing oils by ultrasonic method
• English title: Test method for sonic shear stability of polymer-containing oils
• Replacement relationship: This standard is first published (not provided in the available source regarding replacement of other standards)
• Adoption relationship: Modified adoption of ASTM D2603-01 (2013)
• Publication/implementation: published on 2015-10-27, implemented on 2016-03-01
• Issuing authority: National Energy Administration

2. Scope of application and non-applicability

• This standard specifies a method for determining the shear stability of polymer-containing oils, using an ultrasonic shear apparatus to determine the permanent loss of kinematic viscosity of polymer-containing oils.
• It is applicable to predicting the continuity of shear stability of oils under conditions where the base oil or polymer has not changed.
• It is applicable to specification requirements for polymer additives, especially in the field of hydraulic oils.
• It is not applicable to predicting the shear stability of polymer-containing oils under actual service conditions.

3. Method principle

An appropriate amount of polymer-containing sample is placed in an ultrasonic oscillator and subjected to shear for a certain time, and then the change in sample viscosity is determined using the GB/T 265 method. Reference oils containing easily sheared or shear-resistant polymers should be used frequently for calibration to ensure that the test apparatus applies controlled ultrasonic energy to the sample. Note: The precision data of this standard were obtained under the conditions of 30 mL sample, 10 min and 0 ℃.

4. Reagents and materials (purity / preparation)

• Reference oil A: preferred reference oil, containing polymers that can be broken under high shear rate. Performance is shown in Table 1.
• Reference oil B: second reference oil, containing polymers that can be broken under high shear rate. Performance is shown in Table 1.
• Note: Reference oil A and reference oil B can be obtained from the American Evonik additive company.
• Cleaning solvent: the source text only mentions "a suitable solvent" and does not give a specific name or purity (not provided in the available source).

Table 1 Performance of reference oils

Note: In Table 1, reference oil A appears in two rows of data; this is how the source text is laid out; the 40 ℃ kinematic viscosity value source-text extraction of reference oil B is unclear in the source text, requires confirmation against the source standard (source-text extraction).

5. Apparatus and equipment

• 6.1 Ultrasonic shear apparatus: an oscillator of fixed frequency and an ultrasonic shear rod.
• 6.2 To ensure stable performance, the following auxiliary equipment is recommended:
  • 6.2.1 Cooling bath or ice bath: capable of maintaining a preset temperature, such as 0 ℃;
  • 6.2.2 Beaker: 50 mL;
  • 6.2.3 Sound-insulating box: used to isolate the ultrasonic rod to reduce environmental noise.
• 6.3 Viscometer: a viscometer and constant-temperature bath meeting the requirements of GB/T 265.
• Figure 1: schematic diagram of the ultrasonic generator apparatus (the source text has a figure, source-text extraction does not give details of the text within the figure).

6. Recommended operating conditions

• Sample amount: 30 mL.
• Shear time: 10 min.
• Temperature: 0 ℃ (unless otherwise specified).
• Position of the shear rod: the tip of the shear rod is below the sample liquid surface at 10 mm (see Figure 1); the shear rod should be placed vertically at the central part of the beaker (a lifting platform should be used for support to ensure that the shear rod is fixed in this position).
• Constant temperature: before the shear test, keep at constant temperature for 10 min.
• Power: shear at a preset power for 10 min; experience shows that some instruments need to readjust the controller during shearing to maintain the preset power.
• Calibration target: make the viscosity decrease rate of the reference oil at 40 ℃ be 15.0% (±0.3%), and then use this power value to test new samples.
• The instrument should be recalibrated every day, because the power setting value required to obtain the specified viscosity decrease rate may differ from day to day.

7. Sampling and sample preparation

• 9.1 Pour 30 mL of sample into a clean 50 mL beaker, place it vertically in a constant-temperature bath, set the constant-temperature bath temperature to the required temperature (0 ℃, unless otherwise specified), and let the sample stand for 10 min.
• Other sampling and preparation details are not provided in the available source.

8. Analytical procedure

• 8.3 Place 30 mL reference oil in a 50 mL beaker, immerse the beaker vertically in an ice-water bath or constant-temperature bath so that the sample liquid surface is lower than the constant-temperature bath liquid surface, and keep at constant temperature for 10 min before the shear test. Immerse the ultrasonic shear rod in the sample so that the tip of the shear rod is below the sample liquid surface at 10 mm (see Figure 1); the shear rod should be placed vertically at the central part of the beaker. Shear at a preset power for 10 min. Determine the viscosity decrease rate of the reference oil. If necessary, repeat the determination to determine the appropriate power so that the viscosity decrease rate of the reference oil at 40 ℃ is 15.0% (±0.3%), and then this power value can be used to test new samples. The instrument should be recalibrated every day.
• 8.4 This procedure can be used to establish the severity in a very (source-text extraction unclear in the source text) or after multiple times of shear stability (source-text extraction unclear in the source text) combination. Once the severity conditions are determined, liquids sheared once can be compared (source-text extraction unclear in the source text). If the viscosity decrease rate of 40 ℃ after shearing with the reference oil is outside the conditions of 15.0%±0.5%, this situation should be written into the test (source-text extraction unclear in the source text).
• 9.1 Clean the shear rod with a suitable solvent, then calibrate the instrument according to the procedures of clause 7.3 and clause 7.4. Pour 30 mL of sample into a clean 50 mL beaker, place it vertically in a constant-temperature bath, set the constant-temperature bath temperature to the required temperature (0 ℃, unless otherwise specified), and let the sample stand for 10 min. Immerse the shear rod in the sample as shown in Figure 1, and shear the sample at the power and time determined by the procedures of clause 7.3 and clause 7.4. After the test is completed, pour out the sample and clean the shear rod with a suitable solvent.
• 9.2 Determine the kinematic viscosity values of the sample before and after shearing using the method of GB/T 265.
• Note: The source text 8.2 mentions that "clause 7.3 and clause 7.4 describe the settings of the oscillator and ultrasonic rod", but the contents of clauses 7.3 and 7.4 are not provided in the available source text (requires confirmation against the source standard (source-text extraction)).

9. Qualitative and quantitative determination and calculation formula

• 10.1 Calculate the viscosity loss of the sample (VL) according to formula (1) (%):

  VL = (V₀ − V) / V₀ × 100 ………………(1)

  Where:

  • V₀——the kinematic viscosity of the sample at 40 ℃ before shearing, in square millimeters per second (mm²/s);
  • V—— the kinematic viscosity of the sample at 40 ℃ after shearing, in square millimeters per second (mm²/s).

• 10.2 If the viscosity of the base oil is known, the permanent shear stability index (PSSI) can be calculated by referring to the method of ASTM D6022.

• Terms:

  • 3.1 Viscosity loss (LV) viscosity loss: a measure of the decrease in oil viscosity. Note: Viscosity loss characterizes the decrease in viscosity of the finished oil; in this standard, viscosity loss characterizes the relative rate of change of the decrease in oil viscosity.
  • 3.2 Permanent shear stability index (PSSI) permanent shear stability index: characterizes the irreversible decrease ratio of oil viscosity caused by additives. Note: The permanent shear stability index usually characterizes the shear stability of a single component (additive).

10. Precision

Judge the reliability of test results according to the following provisions (95% confidence level).

• 12.1 Precision
  • 12.1.1 Repeatability r: for tests on the same sample by the same operator using the same instrument, the difference between two consecutive test results should not be greater than 1.6%.
  • 12.1.2 Reproducibility R: for tests on the same sample by different operators in different laboratories using different instruments, the difference between two single, independent test results should not be greater than 3.3%.
• 12.2 Bias: Since test results are defined only by the test method of this standard, this standard has no bias.

11. Report

The report should include the viscosity decrease rate at 40 ℃ of the specified reference oil and sample after shearing for 10 min. If other shear time/temperature are used for calibration, this should be indicated in the report.

12. Referenced documents

• GB/T 265 Petroleum products — Determination of kinematic viscosity and calculation of dynamic viscosity
• SH/T 0103 Determination of shear stability of polymer-containing oils — Diesel nozzle method
• ASTM D6022 standard practice for calculation of permanent shear stability index (calculation method of permanent shear stability index)
• GB/T 1.1—2009 (mentioned in the foreword, used for standard drafting rules)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference for questions and answers