Liquid Ultrasonic Flow Meter — BF70-1
BF70-1 liquid ultrasonic flow meter works mainly on the transit-time (time-difference) method: ultrasonic transducers upstream and downstream transmit alternately, and the flow velocity is derived from the difference in transit times. Available as in-line, clamp-on (no pipe cutting) and insertion. No moving parts, no pressure loss; the clamp-on form is ideal for retrofit and large pipes.
Specifications
| Accuracy | In-line ±0.5~±1.0%; clamp-on ±1~2% |
| Turndown | Wide |
| Method | Transit-time (Doppler version for dirty liquids) |
| Forms | In-line / clamp-on / insertion |
| Straight run | 10D upstream / 5D downstream |
| Output | 4–20mA, pulse, RS485 |
| No pressure loss | Clamp-on: no pipe cutting, live installation |
Details
Working Principle
Transit-time method: ultrasonic transducers are mounted upstream and downstream of the pipe and transmit alternately. Downstream sound travels faster (shorter transit time); upstream sound travels against the flow (longer time). The time difference gives the average liquid velocity; multiplied by pipe cross-section it yields volumetric flow. The transit-time method requires clean media — not too many bubbles or solid particles. A Doppler version relies on reflections from bubbles/particles for dirty media such as sewage.
Advantages / Notes
Advantages: clamp-on needs no pipe cutting, no holes, no shutdown; no pressure loss; no moving parts; very cost-effective on large diameters. Notes: transit-time loses signal with many bubbles or impurities; pipe ID/wall thickness/material must be input; thick scale affects accuracy; clamp-on accuracy drops on small bores.