Fixed Doppler Ultrasonic Flow Meter (RBDF-F)

RBDF-F fixed Doppler ultrasonic flow meter transmitter
  • RBDF-F fixed Doppler ultrasonic flow meter transmitter
  • Clamp-on Doppler transducers for sewage and slurry flow
  • Remote Doppler Open Channel Ultrasonic Flowmeter

RBDOF-F Fixed Doppler Ultrasonic Flow Meter for Open Channel Flow Meter

RBDOF Series Doppler Open Channel flow meter can be used to measure the liquid flow rate of the pipe which is partially filled with liquid. It's Real-Time Flow Monitoring with Precision Control. The ultrasonic Doppler flowmeter collects real-time data on flow velocity, water level, and temperature. It features an LCD display with a Chinese menu for easy operation. The instrument provides clear displays of instantaneous flow, cumulative flow, flow velocity, water level, and cross sectional area. It supports remote data transmission via RS232 or RS485 communication ports and can transmit data online using a 4~20mA analog signal. The instrument allows users to input various parameters based on the site conditions to calculate the cross-sectional area and water flow rate. Engineered for accurate flow measurement in open channels and pipelines, this advanced flowmeter synchronously captures flow velocity, water level, and temperature data. Featuring intuitive bilingual operation and dual-mode data transmission, it delivers reliable hydrological management for water conservancy, municipal, and industrial applications.

Precision monitoring for complex environments. The RBDOF-F Fixed Doppler Ultrasonic Flow Meter is a comprehensive solution for measuring flow in open channels and partially filled pipes. By combining ultrasonic Doppler velocity sensing with integrated depth measurement (Pressure + Ultrasonic backup), it provides high-accuracy "Area-Velocity" data without the need for flumes or weirs. Its compact, low-profile design allows for measurement in low water levels, making it ideal for urban sewer networks, natural streams, and irrigation process monitoring.

Specifications:
• Measurement Range: Velocity: ; Depth: .
• Accuracy: Velocity: ; Water Level: .
• Temperature Range:  (Water);  (Storage).
• Signal Strength Indication: Identifies field conditions like siltation, dry pipe, or high loading.
• Interface: RS485 (Modbus RTU), 4-20mA.
• Protection Class: Transmitter IP65, Sensor IP68.
• Housing Material: Robust PC/ABS for the transmitter; PU cable for harsh chemicals.
Key Advantages:
• Dual-Depth Technology: Features both pressure depth and backup ultrasonic depth measurement for redundant reliability in changing fluid densities.
• Spontaneous Self-Reception Mode: Enables a significantly shorter structural size, allowing for measurement in very low water levels.
• Dual Elevation Angles: Optional  and  angles to adapt to various site conditions and prevent signal loss.
• Internal Flow Calculation: Automatically calculates flow for circular pipes, rectangular channels, trapezoidal channels, and U-shaped channels.
• Rugged Deployment: Designed to withstand pH levels between 6-10 and sediment concentrations up to 20g/L.
If you need mobile monitoring or field testing, please refer to the [Portable Doppler Open Channel Meter]. If you are monitoring full-pipe dirty liquids, please refer to the [Electromagnetic Flow Meter].

 

 

 



 

 

 

 


Description

  • Principle
  • Features
  • Specification
  • Model Selection
  • Applicants
  • Download
Principle

Doppler Ultrasonic Flow Meter for Open Channel Principle: 

The measurement of an ultrasonic Doppler current meter is based on the Doppler effect. The probe emits an ultrasonic wave obliquely upward (or forward), and the ultrasonic wave propagates in the fluid. The fluid contains impurities such as bubbles or particles (it can be considered that the impurities in the fluid have the same velocity as the water flow). When the ultrasonic wave contacts the impurities in the fluid, the reflected ultrasonic wave will produce a Doppler frequency shift Δf, which is proportional to the flow velocity. The flow velocity of the fluid can be measured by measuring the Doppler frequency shift Δf. 

Features

RBDOF Fixed type Open Channel  Doppler Ultrasonic Flow Meter Features: 

  • Wide input voltage: 10VDC～30VDC
  • Small volume: Adopts self-transmitting and self-receiving mode, which greatly shortens the structural size and enables low-water-level measurement.
  • Wide application range: 2 elevation angles are optional, making it more widely applicable in the field.
  • 2 depth measurement methods optional: Pressure-type depth measurement(0°) and backup ultrasonic depth measurement(34°) .
  • Signal strength indication: Capable of distinguishing site conditions such as sedimentation, low water level, and material accumulation.
  • Instantaneous flow calculation function: Can calculate flow for several channel types, including circular, rectangular, trapezoidal, and irregular channels.
  • High protection level: IP68
  • High resolution: Flow velocity resolution of 1mm/s  
  • Convenient installation
Specification

RBDOF Fixed Type Open Channel Doppler Ultrasonic Flow Meter Specification

Source

Power supply range: 10VDC~30VDC ;

Working current: less than or equal to 55mA ;

Power consumption: 0.62W±0.1W (12V power supply) ; 0.83W±0.1W (24V power supply) ;

Output Chara-cteristic

RS485/ModBus standard protocol

Measure Performance

Flow rate range: 0.03m/s~5m/s, -5m/s~-0.03m/s  (customizable ± 0.03m/s~ ±10m/s) ;

Standard type: this model is an external level meter, the type and range of the level meter are selected by the customer ;

Enhanced pressure water depth range: 0.02~3m,0.02~10m  (please confirm the maximum water depth before ordering) ;

Enhanced ultrasonic sounding range: 0. 08~3m (default pressure sounding) ;

Flow rate accuracy:  ±  (V*%1+0.01)m/s  (precision  verified  by hydrological verification center) ;

Flow rate accuracy: ± 1%~ ±3% (the measurement accuracy varies with the influence of the field working environment) ;

Water depth accuracy: ±3cm ;

Flow rate resolution: 1mm/s ;

Temperature resolution: 0.01℃ ;

Enhanced water depth resolution: 1mm (3m range), 3mm (10m range).

Physical Property

Flowmeter material: POM+(ABS+PC) ; cable material: PU ;

Quality: 2.5kg (including 20m wire) ;

Protection class: IP68 ;

Cable: the basic type is 4-core strip shield cable with wire diameter of 4.5mm ; the reinforced type is 4-core strip shield cable with gas pipe, wire diameter of 8mm (the default length is 10 meters, other lengths need to be customized).

Work Environment

Working temperature: -5~60℃ (non-freezing state) ;

Storage temperature: -25~80℃ ;

Sediment concentration: 20mg/L~20g/L ;

pH: PH value between 6 and 10.
Model Selection

RBDOF Fixed for Open Channel  Doppler Ultrasonic Flow Meter Model Selection： 

RBDOF Doppler Open Channel Flow Meter                                                                                                              Model Selection
RBDOF Remote Type Doppler Open Channel Flow Meter
  Level Measure Range
3 3m
10 10m
X xm
  Sensor Material
A ABS
F PTFE
P POM
S  SS316L
X  Other Material
  Power
2 12VDC
4 24VDC
  Output
MA 4-20mA
C2 RS232
C4 RS485
MC 4-20mA+RS232
  Cable Length
1 1m
x Xm(2-50m)
Applicants

RBDOF Fixed for Open Channel  Doppler Ultrasonic Flow Meter Application 

  • Water Resource Management
  • Flood Disaster Early Warning and Monitoring
  • Real-time Monitoring of River/Canal Flow Velocity and Discharge
  • Irrigation Channel Water Consumption Measurement
  • Reservoir Flood Discharge Flow Assessment
  • Municipal Administration and Environmental Protection
  • Sewage Treatment Plant Discharge Flow Monitoring
  • Municipal Pipeline Network Leakage Detection
  • Rainwater Drainage System Load Analysis
  • Automated Recording of Culvert Flow
  • Industry and Scientific Research
  • Circulating Water Measurement for Aquaculture
  • Coastal Erosion Research
  • Flow Control for Water Treatment Processes
  • Hydrological Station Data Collection
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