SH/T 0068-2002 Determination of density or relative density of engine coolants and their concentrates (hydrometer method)

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Card type: Test method

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

• Method number: SH/T 0068-2002
• Chinese full title: Determination of density or relative density of engine coolants and their concentrates (hydrometer method)
• English name: Standard test method for density or relative density of coolant concentrates and engine coolants by the hydrometer
• Replacement relationship: replaces SH/T 0068-91 "Determination of density of engine coolants (hydrometer method)"
• Adoption relationship: equivalent adoption of ASTM D 1122-97a "Determination of density or relative density of engine coolants and their concentrates (hydrometer method)"
• Main technical differences from ASTM D 1122-97a:
  1. The sample temperature was revised from 15.5℃±0.3℃ to 20℃±0.2℃;
  2. In addition to the thermometer specified in the original text, the use of domestic ordinary thermometers is added;
  3. Related expressions of density are added.
• Main technical differences from SH/T 0068-91:
  1. In the title, density was revised to density or relative density;
  2. The light-duty coolant type was removed from the applicable scope of the SH/T 0068-91 hydrometer;
  3. The measuring interval of each hydrometer was expanded from 40 kg/m³ to 50 kg/m³;
  4. Domestic ordinary thermometers are added;
  5. In the test procedure, operations were added to keep the test liquid temperature at 18℃ and to correct the reading for turbid samples;
  6. The hydrometer reading was changed from reading the "upper edge of the liquid surface" to reading the "lower edge of the liquid surface";
  7. A repeatability requirement is added.
• First issue date: 1991 year
• Issue/implementation: issued on 2002-05-31, implemented on 2002-07-01
• Issuing unit: State Economic and Trade Commission
• Drafting unit: Sinopec Sales North China Company
• Main drafters: Zhang Fengquan, Dong Fang
• Technical committee: Sinopec Petroleum Processing Research Institute
• Proposing unit: Sinopec

2. Applicable scope and non-applicability

• 1.1 This standard specifies a method for determining the density or relative density of engine coolants and their concentrates using a hydrometer.
• 1.2 This standard involves certain hazardous materials, operations, and equipment, but it is not intended to address all safety issues associated with them. Therefore, before using this standard, users should establish appropriate safety and protective measures and determine applicable management systems.
• Not applicable: the original text does not explicitly list the non-applicable scope (the light-duty coolant type in SH/T 0068-91 has been removed, see the foreword).

3. Method principle

The original text does not provide an independent "principle" section. The method is the hydrometer method: keep the sample at constant temperature at 20℃±0.2℃, place the hydrometer into the sample, and after it becomes stationary and suspended, read the hydrometer reading (for transparent samples, read the lower edge of the liquid surface; for turbid samples, read the upper edge above the main liquid surface and correct it).

4. Reagents and materials (purity / preparation)

• Transparent solution for calibration: ethylene glycol or propylene glycol solution (used to determine the reading correction value for turbid samples, see 7.4).
• Purity and preparation of other reagents: not provided in the available source.

5. Apparatus and equipment

• 5.1 Hydrometer: made of glass, minimum scale 0.5 kg/m³ (the original text is "minimum scale. .5jia shi", requires confirmation against the source standard (source-text extraction)), main technical requirements are shown in Table 1.
• 5.2 Hydrometer cylinder: made of glass, cylindrical, and a pouring lip may be left on the edge for convenience in pouring; the inner diameter of the cylinder should be at least 25.4 mm larger than the outer diameter of the hydrometer; the height of the cylinder should ensure that after the hydrometer is placed in the test liquid and reaches equilibrium, the height of the sample in the cylinder is at least 25.4 mm more than the portion of the hydrometer immersed below the liquid surface.
• 5.3 Thermometer: should meet the requirements of Appendix A, or use an ordinary thermometer with a temperature range of 0℃～100℃ and a division value of 0.2℃ or 0.1℃.
• 5.4 Water bath: maintain the sample temperature at 20℃±0.2℃ during the test.

Table 1 Hydrometer specifications

Appendix A (normative appendix) Thermometer specifications

Table A1 Thermometer specifications

6. Recommended operating conditions

• Sample temperature: 20℃±0.2℃ (maintained by water bath).
• Sample pretreatment temperature: about 18℃ (maintained before pouring into the cylinder).
• Standing conditions for separated samples: stand at room temperature not lower than 20℃ for 3 h.
• Other conditions: not provided in the available source.

7. Sampling and sample preparation

• 6 Sampling: unless otherwise specified, use SH/T 0065 for sampling.
• 7.1 If a small amount of separation appears in the upper layer of the sample, pour the sample into a 500 mL separatory funnel, let it stand at room temperature not lower than 20℃ for 3 h, and then separate the lower layer sample.
• 7.2 If the coolant is uniform, separation is not necessary.
• 7.3 Keep the separated lower-layer coolant sample or the uniform coolant sample at about 18℃, then carefully pour the sample into a clean, dry hydrometer cylinder without splashing, so as to minimize the possibility of bubble formation.
• Note: When handling the sample (mixing, transferring, or stirring), great care should be taken to avoid bubble formation. A clean, dry glass rod may be used to touch the bubbles to eliminate them.

8. Analytical procedure

• 7.3 Place the cylinder containing the sample vertically in the water bath. When the sample temperature reaches 20℃±0.2℃, slowly place the hydrometer into the sample to a position below the two minimum scale lines, and release the hydrometer. Read when the hydrometer has left the cylinder wall, is stationary and suspended without moving, and the temperature is within the range of 20℃±0.2℃.
• 7.4 Read data from the hydrometer:
  • If the sample is sufficiently transparent: first align the eye slightly below the liquid surface, then slowly raise it until the liquid surface changes from a deformed ellipse into a straight line tangent to the hydrometer scale (read the lower edge of the liquid surface).
  • If the sample is turbid: align the eye with a plane slightly above the liquid surface, and read from the hydrometer scale the upper edge of the sample above the main liquid surface. This reading can be corrected by the amount equal to the height by which the sample rises above the main liquid surface on the hydrometer stem. This height varies with the coolant and the hydrometer, and the correction value depends on the width of the hydrometer scale. The correction value for the hydrometer used can be determined by placing the hydrometer in a transparent solution with the same surface tension as the test sample (such as ethylene glycol or propylene glycol solution) and observing the height by which the transparent solution rises above the main liquid surface on the hydrometer.

9. Qualitative and quantitative determination and calculation formulas

• 3.1 Density density: the mass of a substance per unit volume at a specified temperature, kg/m³.
• 3.2 Relative density relative density: the ratio of the density of a substance at a specified temperature to the density of water at the same temperature.
• 4.1 If the type of glycol in the coolant is known, density or relative density can be used to roughly determine the freezing point, boiling point, and glycol content of the coolant.
• 4.2 Density or relative density can be used as a control index for coolant production.
• Calculation formulas: not provided in the available source.

10. Precision

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

• 8.1 Repeatability: when the density of engine coolants and their concentrates is between 1000.0 kg/m³～1130.0 kg/m³ (relative density between 1.0000～1.1300), the difference between the result measured by the same operator using the same instrument on the same sample and the average value should not be greater than 1.2 kg/m³ (relative density 0.0012).
• 8.2 Reproducibility: when the density of engine coolants and their concentrates is between 1000.0 kg/m³～1130.0 kg/m³ (relative density between 1.0000～1.1300), the difference between the result measured by different operators using different instruments on the same sample and the average value should not be greater than 1.2 kg/m³ (relative density 0.0012).

11. Report

Not provided in the available source.

12. Referenced documents

• SH/T 0065 Sampling of engine coolant or rust inhibitor test samples and preparation of their aqueous solutions
• ASTM D 1122-97a (the equivalent adopted original standard)
• SH/T 0068-91 (the replaced standard)

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 Q&A