Shear Stability Tester for Polymer-Containing Oil (Diesel Nozzle Method) – ASTM D3945, CEC L-14-A-93
The Shear Stability Test (Diesel Nozzle Method) evaluates the viscosity loss of polymer-thickened lubricants (e.g., multigrade engine oils, hydraulic oils, and gear oils) due to mechanical shearing. This test simulates the shearing forces experienced in high-pressure fuel injection systems, gearboxes, and hydraulic circuits.
1. Applicable Standards
✅ ASTM D3945 – Shear Stability of Polymer-Containing Oils Using a Diesel Injector
✅ CEC L-14-A-93 – Diesel Injector Shear Test for Viscosity Loss
✅ ISO 20844 – Viscosity Loss of Polymer-Containing Lubricants
✅ ASTM D6278 – Shear Stability Test (Alternative Rotary Injector Method)
2. Equipment Required
✅ Shear Stability Tester (Diesel Nozzle Injector Type)
✅ High-Pressure Diesel Injector System
✅ Capillary Nozzle (Flow Rate: 3.0 L/min @ 40°C)
✅ Viscometer (ASTM D445, Kinematic Viscosity)
✅ Thermostatic Oil Bath (40°C or 100°C)
✅ Precision Glassware & Measuring Cylinders
3. Test Procedure
Step 1: Sample Preparation
1️⃣ Take a fresh oil sample (50–100 mL) and measure its kinematic viscosity (KV) at 100°C (ASTM D445).
2️⃣ Preheat the oil sample to 40°C for uniformity.
Step 2: Shearing Process (Diesel Injector Shear Test)
3️⃣ Set up the Shear Stability Tester:
- Install the diesel injector nozzle with a calibrated capillary restriction.
- Adjust the injection pressure (10–12 MPa / 100–120 bar).
- Maintain a shear cycle time of 30 passes (standard) or 90 passes (extended).
4️⃣ Pass the oil sample through the injector system:
- The oil is circulated through the high-pressure nozzle.
- Polymers in the oil are mechanically sheared, reducing viscosity.
- The test continues for 30 cycles (or as specified by the standard).
Step 3: Post-Test Viscosity Measurement
5️⃣ After the test, cool the sample to 40°C and measure its kinematic viscosity at 100°C.
6️⃣ Calculate Viscosity Loss (%) using: Viscosity Loss%=KVinitial−KVfinalKVinitial×100\text{Viscosity Loss} \% = \frac{\text{KV}_{\text{initial}} – \text{KV}_{\text{final}}}{\text{KV}_{\text{initial}}} \times 100Viscosity Loss%=KVinitialKVinitial−KVfinal×100
4. Interpretation of Test Results
| Oil Type | Shear Stability Requirement | Max Viscosity Loss (%) |
|---|---|---|
| Multigrade Engine Oil (SAE 5W-30, 10W-40, etc.) | ASTM D3945 | ≤15% |
| Heavy-Duty Diesel Engine Oil (CI-4, CK-4) | ASTM D6278 | ≤10% |
| Hydraulic Oil (ISO VG 46, 68 with VI Improvers) | ISO 20844 | ≤5% |
| Gear Oil (SAE 75W-90, 80W-140) | CEC L-14-A-93 | ≤20% |
✅ Good Shear Stability: Viscosity Loss <10% (High polymer retention)
❌ Poor Shear Stability: Viscosity Loss >15% (Excessive polymer breakdown)
Multi-Function Low Temperature Tester for Lubricants
A Multi-Function Low Temperature Tester is used to evaluate the low-temperature performance of lubricants, greases, and hydraulic fluids. It can measure properties such as pour point, cloud point, low-temperature viscosity, and cold cranking performance.
1. Key Test Standards & Applications
| Test Parameter | Applicable Standard | Purpose |
|---|---|---|
| Pour Point | ASTM D97 / ASTM D5949 | Lowest temp at which oil flows |
| Cloud Point | ASTM D2500 | Temperature where wax crystals form |
| Cold Cranking Simulator (CCS) | ASTM D5293 | Simulates cold-start viscosity |
| Low-Temp Pumpability (MRV) | ASTM D4684 | Measures oil’s ability to flow in cold conditions |
| Low-Temperature Brookfield Viscosity | ASTM D2983 | Evaluates gear and hydraulic oils in cold weather |
| Kinematic Viscosity @ Low Temp | ASTM D445 | Measures fluid thickness at different temperatures |
2. Equipment Features
✔ Programmable Temperature Control: -60°C to +30°C
✔ Multiple Test Chambers: Allows simultaneous testing
✔ Automatic Sample Handling & Detection
✔ Data Logging & Graphical Analysis
3. Typical Test Procedure (Example: Pour Point Test, ASTM D97)
1️⃣ Prepare the Sample
- Pour 50 mL of oil into a test jar.
- Cool it in a controlled-temperature bath.
2️⃣ Monitor Oil Flow Behavior
- Check at every 3°C (5°F) interval for movement.
- Record the temperature when the oil no longer flows.
3️⃣ Record the Pour Point
- The last observed flowing temperature +3°C is the pour point.
4. Interpretation of Results
| Lubricant Type | Typical Pour Point (°C) | Application |
|---|---|---|
| Engine Oil (0W, 5W Grades) | -40°C to -50°C | Cold climates, winter performance |
| Hydraulic Oil (ISO VG 46, 68) | -30°C to -45°C | Industrial, construction machinery |
| Gear Oil (75W-90, 80W-140) | -40°C to -55°C | Transmission, differentials |
| Automatic Transmission Fluid (ATF) | -40°C to -50°C | Automotive, industrial vehicles |
Super Low Temperature Thermostat (Ultra-Low Temperature Circulating Bath)
A Super Low Temperature Thermostat is a precision-controlled cooling system used in laboratories and industries to maintain fluids at ultra-low temperatures. It is essential for lubricant testing, polymer research, battery cooling, and cold-flow property evaluation.
1. Key Applications
✅ Lubricant Testing: Supports ASTM standards for low-temperature viscosity, pour point, and pumpability.
✅ Battery Cooling: Used in lithium-ion battery thermal management systems.
✅ Pharmaceutical & Chemical Research: Maintains precise low-temperature conditions.
✅ Cryogenic Material Testing: Studies material properties at -80°C or lower.
2. Technical Specifications
| Parameter | Typical Values |
|---|---|
| Temperature Range | -80°C to +30°C |
| Cooling Capacity | 500W to 5000W |
| Temperature Stability | ±0.1°C |
| Refrigeration System | Multi-stage compressor or liquid nitrogen cooling |
| Circulating Pump Flow Rate | 10-30 L/min |
| Control System | Digital PID controller with touchscreen |
3. Common Testing Standards Supported
| Test | Standard | Application |
|---|---|---|
| Pour Point | ASTM D97 / D5949 | Lowest temperature oil flows |
| Cold Cranking Simulator (CCS) | ASTM D5293 | Simulates oil viscosity in cold start |
| Mini-Rotary Viscometer (MRV) | ASTM D4684 | Measures oil pumpability in cold |
| Brookfield Viscosity | ASTM D2983 | Evaluates gear & hydraulic oils in cold |
| Kinematic Viscosity | ASTM D445 | Viscosity at different low temperatures |
4. Selection Guide: Choosing the Right Model
| Application | Recommended Temperature Range | Cooling Type |
|---|---|---|
| Engine Oil & ATF Testing | -40°C to -60°C | Single-stage refrigeration |
| Gear Oil & Hydraulic Oil Testing | -50°C to -80°C | Dual-stage refrigeration |
| Battery Cooling & Polymer Research | -60°C to -90°C | Cascade or liquid nitrogen cooling |
5. Advanced Features to Consider
✔ Rapid Cooling: Achieves -80°C in minutes
✔ Circulation System: Ensures uniform temperature in test samples
✔ PID Digital Control: High precision temperature stability (±0.1°C)
✔ Safety Protections: Overload, over-temp, and refrigerant leak detection