1. Product Overview
The GOYOJO Digital Rotary Viscometer NDJ-8S is a precision instrument designed for determining the absolute viscosity of Newtonian liquids. It features a wide measurement range of 1 to 2,000,000 mPa.s, an LCD display for clear readings, and data output capabilities via RS232 to USB connection. This viscometer is widely utilized in various industries for measuring the viscosity of substances such as solvent-based adhesives, emulsions, biochemical products, paints, coatings, cosmetics, lacquers, paper pulp, food, and starch.
Figure 1: GOYOJO Digital Rotary Viscometer NDJ-8S with accessories.
Figure 2: Key features of the Digital Viscometer, emphasizing precision and versatility.
2. Safety Information
- Always operate the viscometer on a stable, level surface to ensure accurate readings and prevent tipping.
- Ensure the power supply matches the instrument's requirements (100-240V, 50-60Hz).
- Do not immerse the main unit in liquid. Clean with a soft, dry cloth.
- Handle rotors with care to avoid bending or damage, which can affect measurement accuracy.
- Keep the instrument away from strong magnetic fields, high temperatures, and corrosive environments.
- Unplug the viscometer from the power source before cleaning or performing any maintenance.
- Only use original or approved replacement parts and accessories.
3. Setup
Proper setup is crucial for accurate viscosity measurements. Follow these steps:
- Unpacking: Carefully remove all components from the packaging. Verify that all parts listed in the packing list are present.
- Base Assembly: Place the base on a stable, level workbench. Adjust the leveling knobs on the base until the instrument is perfectly level.
- Column Installation: Insert the lifting column into the designated slot on the base and secure it firmly.
- Main Unit Attachment: Mount the main viscometer unit onto the lifting column. Use the lifting handwheel to adjust the height.
- Rotor Installation: Select the appropriate rotor for your sample (refer to the "Measuring Different Solutions" section for guidance). Carefully screw the chosen rotor onto the rotor connector at the bottom of the main unit. Ensure it is securely fastened but do not overtighten.
- Power Connection: Connect the power cable to the viscometer and then to a suitable power outlet.
- Temperature Probe (Optional): If using a temperature probe, connect it to the temperature probe connector on the back of the unit.
Figure 3: Labeled components of the viscometer for assembly reference.
Figure 4: Different rotor types and their corresponding measurement ranges at various speeds.
4. Operating Instructions
This section guides you through the process of taking a viscosity measurement.
- Prepare Sample: Pour the liquid to be tested into a suitable beaker or container. Ensure the sample volume is sufficient to fully immerse the selected rotor up to its immersion mark.
- Power On: Turn on the viscometer using the power switch. The LCD display will illuminate.
- Immerse Rotor: Carefully lower the viscometer head using the lifting handwheel until the rotor is immersed in the liquid. Ensure the rotor is centered and not touching the sides or bottom of the container.
- Select Rotor: Press the ROTOR button on the control panel. Use the arrow keys (▲ / ▼) to select the number corresponding to the installed rotor (1#, 2#, 3#, or 4#). Press ENT to confirm.
- Select Speed (RPM): Press the REVS button. Use the arrow keys (▲ / ▼) to select the desired rotational speed (0.3, 0.6, 1.5, 3, 6, 12, 30, 60 rpm). The appropriate speed depends on the expected viscosity of the liquid. For optimal accuracy, aim for a tension angle (displayed as "angle:") close to 50%. Press ENT to confirm.
- Start Measurement: Press the RUN button to begin the measurement. The rotor will start rotating, and the viscosity value (η), rotational speed (rpm), and tension angle will be displayed on the LCD.
- Read Results: Allow the reading to stabilize. The viscosity value (mPa.s) will be displayed. The closer the tension angle is to 50%, the more accurate the viscosity value.
- Stop Measurement: Press the STOP button to halt the measurement.
- Data Output: The NDJ-8S model is equipped with an RS232 to USB cable for data output. Connect the viscometer to a computer using this cable to transfer measurement data for analysis and record-keeping.
Figure 5: LCD Display showing measurement parameters.
Video 1: Demonstration of the GOYOJO Digital Rotary Viscometer NDJ-8S in operation, including sample preparation, rotor insertion, setting rotor and speed, starting the test, and checking results.
5. Maintenance
- Cleaning: After each use, carefully remove the rotor and clean it thoroughly with an appropriate solvent for the tested liquid. Wipe the main unit and stand with a soft, dry, lint-free cloth. Do not use abrasive cleaners or immerse the main unit in water.
- Storage: Store the viscometer and its accessories in a clean, dry, and dust-free environment. Keep rotors in their protective case to prevent damage.
- Calibration: The instrument is factory-calibrated. Regular professional calibration is recommended to maintain accuracy, especially after prolonged use or if readings appear inconsistent.
- Inspection: Periodically inspect the power cord for any signs of damage. Check rotors for any bends or deformities.
Figure 6: The viscometer comes with a factory calibration certificate.
6. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power/Display off | Power cable not connected; Power switch off; Power outlet issue. | Check power cable connection; Turn on power switch; Test power outlet with another device. |
| Inaccurate readings | Rotor not clean; Rotor damaged/bent; Incorrect rotor/speed selection; Instrument not level; Sample temperature fluctuation. | Clean rotor thoroughly; Replace damaged rotor; Verify rotor and speed settings; Level the instrument; Ensure stable sample temperature. |
| Rotor not rotating | Motor malfunction; Rotor not properly attached. | Ensure rotor is securely attached; Contact customer support if motor issue persists. |
| "Angle" reading too low/high | Incorrect rotor or speed selected for sample viscosity. | Adjust rotor or speed to achieve an angle closer to 50% for optimal accuracy. |
7. Specifications
| Parameter | Value |
|---|---|
| Product Number | NDJ-8S |
| Voltage | 100-240V, 50-60Hz |
| Measurement Range | 1-2,000,000 mPa.s |
| Rotor Specification | #1, #2, #3, #4 (four rotors) |
| Measurement Error | ±1% |
| Rotor Velocity | 0.3 / 0.6 / 1.5 / 3 / 6 / 12 / 30 / 60 rpm |
| Ambient Temperature | 5°C-35°C |
| Temperature Display | Optional |
| Temperature Accuracy | 0.1°C |
| Data Output Interface | Yes (RS232 to USB) |
| Data Measurement Software | Optional |
| Relative Humidity | <80% |
| Dimensions | 370mm x 325mm x 280mm |
| Net Weight | 6.8 kg |
Figure 7: Detailed product parameters for the NDJ-8S viscometer.
8. Warranty and Support
This product is covered by the manufacturer's standard warranty. For specific warranty terms, technical support, or service inquiries, please refer to the contact information provided with your purchase or visit the official GOYOJO website. Keep your purchase receipt as proof of purchase for warranty claims.