Wall-mounted Doppler Open Channel Flow Meter

Doppler Open Channel flow meter can be used to measure the liquid flow rate of the pipeline which is partially filled with liquid.
Principle:  Use Doppler frequency shift to measure the flow velocity, it is suitable for measuring the fluid which contains solid particles or bubbles, not suitable for measuring pure water.
Application scope:  City pipe network, underground sewage testing, sewage treatment plants, streams and rivers testing.

Product Description

Brief introduction:

Wall-mounted type Doppler Open Channel flow meter consists of a wall-mounted flow calculator and a transducer. The transducer consists of a flow velocity sensor, a water depth sensor of ultrasonic principle, a water depth sensor of pressure principle and a conductivity sensor, which are separately used to measure flow velocity, depth, and conductivity of water in rivers, streams, open channels and pipelines.


Composition of the transducer: 

transducer structure

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Detailed illustration for the transducer as follows:

 1)  Water flow velocity measurement uses Ultrasonic Doppler principle in Quadrature Sampling Mode. The flow sensor transmits ultrasonic energy through its epoxy case into the water. The suspended sediment particles or small gas bubbles in the water reflect some of the transmitted ultrasonic energy back to the flow sensor’s ultrasonic receiver which processes this received signal and calculates the water flow velocity.

  2) Two methods for water depth measurement. One method is using the top mounted ultrasonic sensor in the transducer to measure water depth. Another method is using the bottom mounted pressure sensor in the transducer to measure water depth. User should select the suitable water depth measuring method according to the on-site condition.

  3) In the transducer, there is a conductivity meter which has 4 conductivity electrodes which expose to the water at the top of the transducer. When the transducer is working, the conductivity electrodes continuously measure the conductivity of the water for user analyzing the nature of the water in open channels or pipes.



● The fluid must contain a certain amount of air bubbles or suspended solid particles
● 20 coordinate points to describe cross section of the river’s shape.
● Measurement of flow velocity, depth and conductivity of water.
● Flow Velocity Range: 0.02 ~ 0.8m/s,  0.02 ~ 1.6m/s, 0.02 ~ 3.2m/s, 0.02 ~ 6.4m/s, 0.02 ~ 13.2m/s,  bi-directional, accuracy  1%.
● Depth measurement by the principles of pressure sensor or ultrasonic level sensor.
● Depth Range: 0.02 to 5 m (for ultrasonic principle, error: ±1mm); 0 to 10m (for pressure principle, error: ±2mm).
● Flow velocity measurement in both forward direction and reverse direction
● With coordinate correction and pressure compensation function.
● IP68 Epoxy-sealed body design for transducer, long time working under water.
● RS485 communication (MODBUS protocol) optional, for connecting to the upper computer.


Technical data of  Transducer:

Velocity: Velocity range: 0.02 ~ 0.8m/s,  0.02 ~ 1.6m/s, 0.02 ~ 3.2m/s, 0.02 ~ 6.4m/s, 0.02 ~ 13.2m/s, Bidirectional
Velocity accuracy: ±1% measured velocity
Velocity resolution: 1mm/s
(Ultrasonic principle):
Range: 0.02 to 5 m
Accuracy: ± 1% of measured
Resolution: ± 1 mm
(Pressure principle):
Range: 0 to 10 m
Accuracy: ± 1% of measured
Resolution: ± 2 mm
Temperature: Range: 0°C to 60°C
Accuracy: ±0.5°C
Resolution: 0.1°C
Electrical Conductivity (EC): Range: 0 to 200,000 µS/cm, Typically ± 1% of measurement
Resolution: ±1 µS/cm
recorded as a 16-bit value (0 to 65,535 µS/cm) or a 32-bit value (0 to 262,143 µS/cm)
Range: ±70° in roll and pitch axes.
Accuracy: ±1° for angles less than 45°
Output: SDI-12: SDI-12 v1.3, Max. cable 50m
RS485: Modbus RTU, Max. cable 500m
Environmental: Operating temperature:  0℃ ~+60℃ water temperature
Storage temperature:  -20℃ ~+60℃
IP class: IP68
Others: Cable: The standard cable is 15m, the maximum option is 500m.
Sensor material: Epoxy-sealed body, Marine Grade 316 Stainless Steel Mounting Bracket
Sensor size: 135mm x 50mm x 20mm (L x W x H)
Sensor weight: 1kg with 15m of cable


Technical data of Flow calculator:

Type: Wall-mounted
Power supply: Calculator: 220VAC & 12-24 VDC; Sensor: 12VDC
IP class: Calculator: IP66
Operating temperature:  0℃ ~+60℃
Case material: Fiber Glass
Display: 4.5” color LCD
Output: Pulse,4-20mA(Flow & Depth),RS485/Modbus, Datalogger, GPRS
Size: 244L×196W×114H (mm)
Weight: 2.4 kg
Data storage: 16GB
Application: Partially Filled Pipe: 150-6000mm; Channel: width >200mm


Installation Diagram:

install diagram 1f

                                   Partially pipe                                                    Pipe with siltation on bottom           


install diagram 2f

                            Triangle Channel                                                              Rectangular channel


install diagram 3f

                            Polygonal channel                                                   Irregular-shaped channel





Answer : Please send your question or enquiry to our email: sales@hginstrument.com, we will forward the questions to the related engineer.

Answer :  Please communicate with the sales about the return procedure before returning product.

Answer :  The delivery time depends on the order quantity and product specification.  If the product’s specification is conventional ( not special ),  delivery time is 5 or 7 working days for order quantity ≤ 10 pieces;  delivery time is 2 or 3 working weeks for order quantity 15 ~ 30 pieces. 

Answer :  by Courier,  by Sea or by Air

Answer :  Yes,  Generally warranty is one year.

Answer :  From year 2015  to year 2021,  average annual sales is RMB 350 million ( about USD 54.7 million )

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