Clamp-on Doppler flowmeters are exclusively suitable for liquids containing a certain amount of acoustic scatterers, relying on the principle of Doppler effect to measure flow velocity by detecting frequency shifts in sound waves reflected by scatterers (e.g., particles, bubbles) in the fluid. Below are the specific liquid types and critical conditions for their application:
Core Suitable Liquid Types
1. Liquids with Solid Particles
Typical Media:
Sewage, slurry, mineral pulp, paper pulp, industrial wastewater (containing particles such as sediment, debris, fibers, typically with particle size ≥30 μm).
Particle-laden liquids in the food industry (e.g., fruit juice with pulp, sauces, grain-containing beverages).
Suspensions in the chemical industry (e.g., catalyst particle mixtures, pigment slurries).
Key Requirements:
Particle concentration must be ≥100 ppm to ensure sufficient acoustic reflection signals.
The acoustic impedance of particles must differ significantly from that of the liquid (e.g., solid particles exhibit better reflection effects due to large impedance differences with water).
2. Liquids with Bubbles
Typical Media:
Gas-liquid two-phase flows (e.g., industrial process fluids with air bubbles, beer fermentation liquids).
Stirred or aerated liquids (e.g., effluent from aeration tanks in wastewater treatment).
Considerations:
Bubbles must be uniformly dispersed in the liquid, avoiding “gas clusters” or excessive free gas (which may cause unstable signal scattering).
3. Turbid or Opaque Liquids
Typical Scenarios:
Liquids where optical measurement methods (e.g., magnetic flowmeters) are ineffective due to poor penetrability (e.g., dark-colored chemical solutions, muddy water).
Pastes or emulsions in the food industry (e.g., chocolate sauce, emulsified oils).
Post time: Jun-04-2025