6AAB Thermal Mass Flowmeter Overview
6AAB thermal mass flowmeter is a gas mass flow measurement instrument designed based on the thermal diffusion principle. It can directly output gas mass flow without temperature and pressure compensation, and is suitable for various industrial gas measurement scenarios. This article provides a concise manual to help engineering technicians and procurement personnel quickly grasp its core information.
Download 6AAB Chinese Manual.pdf
Working Principle and Core Advantages
Thermal Measurement Principle
The sensor contains two temperature probes: a heating probe and a reference probe. When gas flows through the heating probe, it takes away heat. By measuring the heating power or temperature difference change, the mass flow can be calculated. This principle directly reflects the number of gas molecules and is not affected by pressure and temperature.
Main Technical Features
- Direct mass flow measurement, no additional temperature and pressure compensation required
- Wide turndown ratio, usually up to 100:1 or more
- Sensitive measurement at low flow rates, suitable for small flow gas monitoring
- No moving parts, minimal pressure loss, low maintenance cost
- Supports multiple output signals: 4-20mA, RS485, pulse, etc.
Technical Parameters and Selection Reference
Typical Performance Parameters
| Parameter | Typical Value | Remarks |
|---|---|---|
| Measurement Medium | Air, nitrogen, oxygen, argon, etc. | Gas composition must be specified |
| Flow Range | 0~10 Nm/s to 0~120 Nm/s | Customizable |
| Accuracy | ±1% FS | Under standard conditions |
| Operating Temperature | -20℃ ~ +60℃ | Ambient temperature |
| Operating Pressure | ≤1.6 MPa | Higher pressure requires optional configuration |
| Output Signal | 4-20mA / RS485 / Pulse | Optional |
| Power Supply | 24VDC | ±10% |
| Protection Rating | IP65 | IP67 optional |
Selection Notes
- Confirm the gas type and component proportions; for mixed gases, detailed composition must be provided
- Determine the maximum flow rate and minimum flow rate to ensure the range covers the application
- Verify pipe size and connection method (flange, thread, ferrule)
- Consider ambient temperature, pressure, and explosion-proof requirements
Installation Steps and Precautions
Installation Steps
- Confirm that the gas flow direction in the pipeline matches the sensor arrow direction.
- Ensure upstream and downstream straight pipe lengths: upstream ≥5D, downstream ≥3D (D is the pipe inner diameter).
- Insert the sensor into the pipeline and secure it, ensuring the probe is positioned at the center of the pipeline.
- Connect power and signal cables, paying attention to correct polarity.
- After power-on, check the zero point and calibrate if necessary.
Installation Precautions
- Avoid installation in locations with strong vibration or drastic temperature changes
- Ensure there is no condensate water or dust accumulation in the pipeline; install a filter if necessary
- For horizontal pipelines, the sensor should be installed on the side or top of the pipeline to avoid liquid accumulation at the bottom
- For explosion-proof applications, intrinsically safe or flameproof products must be selected
Maintenance and Troubleshooting
Daily Maintenance
- Regularly check whether the probe is clean; if dirty, wipe with a soft cloth dipped in alcohol
- Calibrate the zero point and span every six months to one year
- Check whether the terminal connections are loose and whether the seals are intact
Common Faults and Solutions
| Fault Symptom | Possible Cause | Solution |
|---|---|---|
| No output signal | Power not connected or reverse polarity | Check power supply and wiring |
| Reading too low | Probe contamination or gas composition change | Clean probe and recalibrate |
| Large reading fluctuation | Unstable flow field or insufficient straight pipe length | Improve installation conditions |
| Zero drift | Large ambient temperature change or sensor aging | Re-zero; replace sensor if necessary |
For the complete manual, please download the PDF file above, or contact the manufacturer's technical support for detailed guidance.