Lubricating Oil Anti-Foam Tester – ASTM D892
The Anti-Foam Test for Lubricating Oils (ASTM D892) evaluates an oil’s ability to resist foam formation and break down foam efficiently. This test is crucial for engine oils, hydraulic fluids, gear oils, and turbine oils, as excessive foam can cause poor lubrication, cavitation, and system failure.
1. Equipment & Materials Needed
A. Instrumentation
✅ Foam Test Bath – Must maintain temperature at:
- Sequence I & II: 24°C (75°F)
- Sequence III: 93.5°C (200°F)
✅ Foam Test Cylinders
- Graduated 1000 mL glass cylinders with inlet diffusers
✅ Air Supply System
- Filtered, dry air at 94 mL/min ± 5 mL/min
✅ Temperature Control System
- Water/Oil Bath to maintain proper test conditions
✅ Timer & Measuring Scale
- Accurate timing for foam collapse measurement
2. Testing Procedure (ASTM D892)
A. Sample Preparation
1️⃣ Ensure oil sample is homogeneous – If necessary, stir before testing.
2️⃣ Prepare foam test cylinders – Clean with solvent and dry completely.
3️⃣ Measure 200 mL of oil and pour into each cylinder.
B. Test Execution
Step 1: Sequence I (24°C, Initial Foaming Tendency & Stability)
- Place the oil-filled cylinder in a 24°C water bath.
- Inject filtered air (94 mL/min) for 5 minutes.
- Stop air injection and record:
- Foam Volume (mL) immediately (Foaming Tendency).
- Foam Volume after 10 minutes (Foam Stability).
Step 2: Sequence II (93.5°C, High-Temperature Foaming)
- Heat the oil to 93.5°C in the bath.
- Repeat air injection (94 mL/min for 5 min).
- Record foam volume immediately and after 10 minutes.
Step 3: Sequence III (24°C, After High-Temperature Exposure)
- Cool the oil sample back to 24°C.
- Repeat air injection for 5 minutes.
- Record foam volume immediately and after 10 minutes.
C. Data Recording & Interpretation
✅ Typical Foam Test Results (ASTM D892 Format)
| Sequence | Temperature | Foaming Tendency (mL, Initial Foam) | Foam Stability (mL, After 10 min) |
|---|---|---|---|
| Sequence I | 24°C | 10–50 mL | 0–10 mL |
| Sequence II | 93.5°C | 50–150 mL | 0–20 mL |
| Sequence III | 24°C (After Heating) | 10–100 mL | 0–10 mL |
🔹 Good Anti-Foam Performance → Low initial foam & fast collapse.
🔹 Poor Anti-Foam Performance → High foam levels & slow collapse (requires defoaming additives).
3. Factors Affecting Foaming
| Factor | Effect |
|---|---|
| Base Oil Type | Some base oils foam more than others |
| Anti-Foam Additives | Reduce foam formation & improve collapse time |
| Contaminants (Water, Particles, Oxidation) | Increase foam tendency & decrease stability |
| Temperature | Higher temperatures usually increase foaming |
4. Quality Control & Calibration
✅ Reference Oil Calibration
- Use known standard oils to validate test results.
✅ Airflow Calibration
- Ensure 94 mL/min ± 5 mL/min for accurate testing.
✅ Duplicate Testing
- Run tests twice; results should be within ±10% repeatability.
5. Troubleshooting & Common Issues
| Issue | Possible Cause | Solution |
|---|---|---|
| Excessive foam formation | Contaminants in oil (water, oxidation) | Filter or dry the oil before testing |
| Foam does not collapse | Insufficient anti-foam additives | Add anti-foam agent (e.g., silicone defoamer) |
| Test cylinder contamination | Residue from previous tests | Clean with solvent & dry thoroughly |
| Incorrect airflow rate | Clogged air diffuser or incorrect settings | Check and calibrate air supply |
6. Advantages of the Anti-Foam Test (ASTM D892)
✔ Standardized & Repeatable – Used globally in lubricant testing.
✔ Predicts Performance in Real Applications – Essential for hydraulic, gear, and turbine oils.
✔ Helps Optimize Additive Formulations – Important for defoamant selection.
Immersed Refrigerator (Cryogenic or Ultra-Low Temperature Bath System)
An immersed refrigerator or cryogenic ultra-low temperature bath system is designed for precise cooling of liquids in laboratory and industrial applications. These systems can achieve ultra-low temperatures (-80°C to -196°C) and are commonly used in:
✅ Material Testing (metals, polymers, lubricants)
✅ Pharmaceutical & Biotechnology Research
✅ Cryogenic Fluid Cooling
✅ Viscosity & Rheological Studies
1. Key Components & Features
A. Cooling System
- Refrigeration Compressor (single or cascade system for ultra-low temps)
- Cryogenic Liquid Cooling (uses LN₂ or CO₂ for extreme cold)
- Temperature Control Unit (PID or digital for precision)
B. Immersion Bath
- Stainless Steel Tank (corrosion-resistant)
- Coolant Fluid (ethanol, methanol, or silicone oil)
- Insulated Walls (to prevent heat loss)
C. Circulation & Control
- Magnetic Stirring or Pump Circulation (for uniform cooling)
- Digital or Touchscreen Display
- Programmable Temperature Ranges
2. Common Types of Cryogenic Baths
| Type | Temperature Range | Cooling Method | Application |
|---|---|---|---|
| Ultra-Low Refrigerated Bath | -80°C to 0°C | Mechanical Refrigeration | Viscosity testing, lubricant cooling |
| Cryogenic Immersion Bath | -196°C to -80°C | Liquid Nitrogen (LN₂) | Material freezing, biotech research |
| Ethylene Glycol Refrigeration Bath | -40°C to 0°C | Mechanical Refrigeration | Chemical & pharmaceutical cooling |
3. Selecting the Right System
🔹 Temperature Requirement: Choose a bath that meets your minimum required temperature.
🔹 Cooling Medium: Ethanol, silicone oil, or LN₂ depending on application.
🔹 Tank Volume: Ensure it fits your sample size.
🔹 Circulation Type: Stirred or pumped for temperature uniformity.