SH/T 0791-2007 Determination of engine oil filterability (after water treatment and prolonged heating)

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

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

• Method number: SH/T 0791—2007
• Chinese full title: Determination of engine oil filterability (after water treatment and prolonged heating)
• English name: Standard test method for measuring the effect on filterability of engine oils after treatment with various amounts of water and a long (6-h) heating time
• Replacement relationship: not provided in the available source (the foreword only states modified adoption of ASTM D6794-02, and does not list the replaced standard number)
• Adoption relationship: modified adoption of ASTM D6794-02 "Determination method for engine oil filterability (after water treatment and prolonged (6h) heating)"
• Publication/implementation: published on 2007-08-01, implemented on 2008-01-01
• Proposal/administration/drafting: proposed by China Petrochemical Corporation; administration by the Petrochemical Research Institute of China Petroleum & Chemical Corporation; drafted by the Lubricant Branch of China Petroleum & Chemical Corporation; main drafters Cui Haiou, Meng Xuemei, Zhang Chunhui
• Main technical differences from ASTM D6794-02 (foreword): some referenced standards adopt the corresponding national standards of our country; added the mechanical oscillator in clause 6.8 and the requirement for oscillating the sample before testing in clause 9.5; refined the content of clause 9.3
• Editorial modifications: the expressions of repeatability and reproducibility were modified according to the practice of our country; the chapter of keywords was deleted
• Annex A is an informative annex

2. Scope of application and non-applicability

• 1.1 This standard specifies the determination method for the filterability of engine oils in the presence of water. It simulates the tendency to form deposits that easily clog filters during long-term storage when water is present in the oil after a new engine has been run for a short period.
• 1.2 This standard uses SI [S] units (requires confirmation against the source standard (source-text extraction): the source text reads as such).
• 1.3 This standard involves certain hazardous materials, operations and equipment, but does not purport to address all safety problems associated with them. Therefore, it is necessary for the user to establish appropriate safety and protective measures and determine the corresponding management system before using this standard.
• Non-applicable scope: not provided in the available source.

3. Method principle

• Chapter 4 Method summary: treat the sample with deionized water, heat to 70℃ and hold for 6h, then store at room temperature. Filter the sample, calculate the flow rate of the sample, and determine the filterability of the engine oil. (the sample-treatment and storage wording is garbled in the source transcription; verify the procedure before use)

4. Reagents and materials (purity / preparation)

• 7.1 Purity of reagents: in all tests, use chemically pure reagents. Unless otherwise specified, all reagents shall meet the requirements of GB/T 603. If it can be demonstrated that a reagent is of sufficiently high purity not to affect the precision of the determination, other grades of reagent may also be used.
• 7.2 Water: unless otherwise specified, use water that meets the deionized water specified as grade three in GB/T 6682.
• 7.3 Reference oil: the ASTM Test Monitoring Center can provide TMC reference oil.
• Other materials: filter paper, diameter 25mm (pore size 25μm), should be cut to a size suitable for the filter (see 6.1.4).

5. Apparatus and equipment

• 6.1 The equipment includes a 25mL burette, a filter fitted with filter paper of pore size 25μm, and a compressed air source of 69kPa±2kPa (see Figure 1).
• 6.1.1 Burette: 25mL, made of plastic or glass. With a polytetrafluoroethylene stopcock and an open burette tip with an inner diameter of 18mm±0.1mm.
• 6.1.2 Air pressure regulator: adjust the pressure so that it can reach 69kPa±2kPa.
• 6.1.3 Filter assembly: with a filter, effective filtration area approximately 0.8cm².
• 6.1.4 Filter paper: diameter 25mm (pore size 25μm), the filter paper should be cut to a size suitable for the filter.
• 6.2 Stirrer: rotation speed 18000r/min±1800r/min.
• 6.2.1 Stopwatch: capable of measuring 30s±1s (the stopwatch specification is garbled in the source transcription and remains unverified).
• 6.3 Mixer: 250mL, with blades matching the stirrer.
• 6.4 Syringe: 1000μL.
• 6.5 Glass bottle: a 60mL bottle with a lined cap.
• 6.6 Oven: temperature can be maintained at 70℃±1℃.
• 6.7 Time sensor (or other equivalent timing instrument): measurement resolution 1s.
• 6.8 Mechanical oscillator.
• Figure 1: Engine oil filterability tester (including air supply connector, 25mL burette, air pressure regulator 69kPa, connecting tube, filter assembly).

6. Recommended operating conditions

• Mixing speed: 18000r/min±1800r/min, mixing time 30s±1s (9.1).
• Heating aging: place in an oven at 70℃±1℃ for 6h (9.2).
• Cooling/storage temperature: room temperature (20℃~24℃), protected from light (9.2, 9.4).
• Time limit for filterability determination: after the test oil is taken out of the oven, determine its filterability within 48h±2h (9.5).
• Filter drying: dry in an oven at 70℃±2℃ for 30min±2min, store in a desiccator for later use (9.6).
• System pressure: 69kPa±2kPa (10.2, 10.3).
• Flow rate measurement interval: the time required for every 5mL of oil to flow out within the 0mL~25mL segment (10.2, 10.3).

7. Sampling and sample preparation

• 8 Sampling: sample according to the requirements of GB/T 4756.
• 9.1 Mix 49.7g±0.1g of new oil and 0.3g±0.05g of deionized water (added with a 1000μL syringe into 0.3mL±0.05mL) in a mixer, and mix at a speed of 18000r/min±1800r/min for 30s±1s, cover with a lid to prevent the test oil sample from splashing out.
• 9.2 Pour the test oil into a 60mL glass bottle, tighten the cap, then loosen it by one quarter turn, and place it in an oven at 70℃±1℃ for 6h. Remove the sample from the oven, tighten the cap and cool to room temperature (20℃~24℃).
• 9.3 According to clauses 9.1 and 9.2, respectively: mix 0.5g±0.05g of deionized water into 49.5g±0.1g of new oil; mix 1.0g±0.05g of deionized water into 49.0g±0.1g of new oil; mix 1.5g±0.05g of deionized water into 48.5g±0.1g of new oil.
• 9.4 Store the test oil at room temperature (20℃~24℃) in a dark place.
• 9.5 After the test oil is taken out of the oven, determine its filterability within 48h±2h; before filtration, place the glass bottle containing the test oil upside down in a mechanical oscillator and oscillate at high speed until there is no sediment at the bottom of the bottle.
• 9.6 Dry the filter in an oven at 70℃±2℃ for 30min±2min, and store it in a desiccator for later use.

8. Analysis procedure

• 10.1 Install the test equipment according to Figure 1, place the filter gasket, filter element and filter paper in the filter, with the smooth side of the filter paper facing up. Tighten the upper and lower parts of the filter and connect to the burette.
• 10.2 Determine the flow rate of new oil as it passes through the burette. Apply pressure to the system so that at least 10mL of new oil passes through the filter, ensuring that the new oil fills the filter and removes air bubbles. Remove the air connection tube, fill the burette with new oil to 1cm–2cm above the 0 mark. Adjust the pressure system to 69kPa±2kPa, open the stopcock, and measure the time required for every 5mL of oil to flow out within the 0mL–25mL segment.
• 10.3 To determine the flow rate of the test oil, first after measuring the flow time of the new oil, drain the new oil as much as possible to the lowest level of the burette, and ensure that no air bubbles are allowed below the stopcock. Use the same filter element, filter and burette to measure the test oil. Remove the air connection tube, load the uniformly mixed test oil into the burette to 1cm–2cm above the 0 mark. Adjust the pressure system to 69kPa±2kPa, open the stopcock, and measure the time required for every 5mL of oil to flow out within the 0mL–25mL segment.
• 10.4 Each non-reference oil and reference oil shall be tested in duplicate, that is, repeat the procedure of Chapter 9 and clauses 10.1~10.4 for each non-reference oil and reference oil.
• 10.5 For tests under the monitoring of TMC, the TMC reference oil and non-reference oil shall be determined on the same day.
• 10.6 For tests not under the monitoring of TMC, an oil of guaranteed quality may be used instead of the TMC reference oil.

9. Qualitative and quantitative determination and calculation formulas

• 11.1 The flow rate per 5mL of new oil and test oil (v) is calculated according to formula (1):
  • v = A / B ……………………………………(1)
  • Where: A— volume of oil, mL; B— flow time, s.
• 11.2 The percentage change in flow rate of the test oil relative to the new oil (Δ) is calculated according to formula (2) (the final-stage flow rate refers to the flow rate of 20mL~25mL. The same filter element is used for the test oil and new oil):
  • Δ = (D − E) / D × 100 ……………………(2)
  • Where: D— final-stage flow rate of new oil, mL/s; E— final-stage flow rate of test oil, mL/s.
  • (the correspondence between equation symbols and variables is garbled in the source transcription; verify the equation before calculation)

10. Precision

• Judge the reliability of the 25μm filter paper test results according to the following provisions (confidence level of 95%).
• 14.1.1 Repeatability r: the difference between two consecutive test results obtained by the same operator, using the same test equipment and the same test method on the same sample shall not be greater than 11.1%.
• 14.1.2 Reproducibility R: shall be greater than 25.4%. (requires confirmation against the source standard (source-text extraction): the original text states "shall be greater than 25.4%", which differs from the usual way reproducibility is expressed)
• 14.2 Bias: the difference between two test results obtained by different operators, using different test equipment, with the same test method on the same sample; because there is no acceptable reference material for this test method for bias determination, this bias cannot be determined.

11. Report

• 13 Report, the test results shall include the following:
  • 13.1 Identification of the non-reference oil or reference oil.
  • 13.2 The pore size of the filter paper used (25μm).
  • 13.3 The percentage change in flow rate at the final stage of each test.
  • 13.4 The average percentage change in flow rate at the final stage of repeated tests.
  • 13.5 For TMC monitoring tests, meet the reporting content requirements of TMC.
  • 13.6 For tests not under TMC monitoring, oils that ensure quality and have known filterability results may be used to evaluate whether the test results are acceptable.

12. Normative references

• GB/T 603 Chemical reagents—Preparation of preparations and products used in test methods
• GB/T 4756 Petroleum liquids—Manual sampling (GB/T 4756—1998, ISO 3170:1988, MOD)
• GB/T 6682 Water for analytical laboratory use—Specification and test methods (GB/T 6682—92, ISO 3696:1987, NEQ)
• ASTM D4485 Standard specification for performance of engine oils
• ASTM D6794-02 (the original standard adopted with modification)

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