Precession Vortex Flow Meter — BF50R
BF50R precession vortex flow meter is a new-generation gas meter with high commonality of parts, SMT circuits and high reliability. Used mainly for gas: natural gas, compressed air, coal gas and liquefied gas. The vortex generator forces the axial flow into rotation, forming a vortex core that precesses; the oscillation frequency is proportional to volumetric flow.
Specifications
| Accuracy | ±1.0 (special ±0.5) |
| Repeatability | 0.2 (best 0.1) |
| Turndown | Up to 25:1 |
| Velocity range | Liquid 0.2–4; gas 2–40; steam 2–50 m/s |
| Media | Gas mainly; some low-viscosity liquid; steam |
| Temperature | -40 to +300 °C |
| Straight run | 10D upstream / 5D downstream |
| Output | Pulse, 4–20mA, RS485; 24VDC or battery |
| No moving parts | No 3-valve manifold or impulse lines required |
Details
Working Principle
Fluid enters the sensor and the vortex generator forces the axial flow to rotate, forming a vortex core; under back-flow the core undergoes secondary spiral precession. The precession frequency is proportional to volumetric flow. A piezoelectric sensor picks up the frequency, and the converter outputs 4–20 mA or pulse. Frequency is limited by Reynolds number; the meter coefficient depends only on geometry. Mass flow requires temperature/pressure compensation.
Structure
- Sensor: vortex generator, piezoelectric detecting sensor, outlet rectifier
- Converter: amplifier, filter, shaping, microprocessor, display
- The rectifier restores the vortex flow to axial flow and eliminates downstream swirl effects
Performance & Notes
- Media: gas mainly, some low-viscosity liquid, steam
- Accuracy ±1.0% (special ±0.5%); repeatability 0.2% (best 0.1%); turndown up to 25:1
- Displays instantaneous flow, total, temperature/pressure, mass flow
- No moving parts; no 3-valve manifold or impulse lines
- vs. vortex: better for small/medium gas lines; higher pressure loss