I. Overview of the 6F3B Thermal Gas Mass Flow Meter
The thermal gas mass flow meter is based on the thermal diffusion principle and directly measures gas mass flow without the need for temperature and pressure compensation. The 6F3B series is suitable for various gases such as air, nitrogen, and natural gas, and is widely used in industrial process control and energy metering.
Click to download the complete "6F3B Chinese Manual.pdf" for detailed technical information.
II. Working Principle and Technical Advantages
2.1 Thermal Diffusion Measurement Principle
The sensor consists of two platinum resistors, one for heating and one for temperature measurement. When gas flows through, it carries away heat, and the heating power is proportional to the mass flow rate, which is converted into a standard signal by the circuit.
2.2 Core Advantages
- Direct mass flow measurement, no temperature and pressure compensation required
- Large turndown ratio, suitable for low flow rate measurement
- No moving parts, minimal pressure loss, low maintenance
- Fast response, suitable for dynamic processes
III. Main Technical Specifications
| Parameter | Specification |
|---|---|
| Measurement range | 0～120 Nm/s (optional) |
| Accuracy | ±1% FS |
| Working pressure | ≤4.0 MPa |
| Medium temperature | -40℃～+200℃ |
| Output signal | 4-20mA / RS485 / Pulse |
| Power supply | 24VDC / 220VAC |
IV. Installation and Wiring Guide
4.1 Installation Steps
- Confirm that the pipe size matches the flow meter specifications and select a location with sufficient straight pipe sections (10D upstream and 5D downstream).
- Drill a hole in the pipe and weld the mounting base, ensuring good sealing.
- Insert the sensor into the pipe, adjust the insertion depth to near the centerline, and tighten the nut.
- Check that the flow direction arrow matches the gas flow direction to avoid reverse installation.
4.2 Electrical Wiring
- Power wiring: Connect 24VDC to terminals + and -, observe polarity.
- Signal output: Connect 4-20mA to the corresponding terminals, load resistance ≤500Ω.
- Communication interface: Use shielded twisted pair for RS485 A/B lines, keep away from power cables.
V. Parameter Setting and Commissioning
5.1 Basic Parameter Setting
Enter the menu via panel keys or host software, and set the pipe inner diameter, gas type, upper range limit, damping time, etc. in sequence. Ensure the parameters match the actual working conditions.
5.2 Calibration and Zero Adjustment
- Ensure there is no gas flow in the pipe, and enter the zero calibration menu.
- Perform zero calibration; the meter automatically records the current zero point.
- Introduce standard gas or use a standard meter method for span calibration.
VI. Common Faults and Troubleshooting
| Fault Symptom | Possible Cause | Solution |
|---|---|---|
| No output signal | Power reversed or disconnected | Check power polarity and wiring |
| Large reading deviation | Sensor contamination or wrong parameters | Clean sensor, verify parameters |
| Output fluctuation | Unstable gas flow or poor grounding | Stabilize gas source, check grounding |
VII. Maintenance and Care Recommendations
- Regularly inspect the sensor surface and remove dust or oil contamination.
- Perform zero and span calibration annually.
- For long-term shutdown, disconnect power and protect the sensor.
- Avoid use under pressure and temperature conditions beyond specifications.
Following this manual ensures long-term stable operation of the 6F3B thermal gas mass flow meter. For the complete document, please download the "6F3B Chinese Manual.pdf".