Open Channel Flowmeters & Venturi Flumes & Weirs

SGM-600F
Area velocity flowmeter
Flow measurements in open channels.
No need for a hydraulic primary.
4 ÷ 20mA analogue output.
MODBUS RTU communication port.
16GB SD card datalogger.
Up to 20 points for the configuration of the irregular profile of a channel.
Flowmeter for open-air ducts and open channels with the possibility of satisfying the most varied channel geometries. The system is able to receive the average speed by ultrasonic doppler method and to read the level of the hydraulic head by means of a hydrostatic detector. The system is also applicable in situations of heavy submergence or regurgitation (Q = average V for wet area). SGM-600 is installed without the need for hydraulic modelers such as venturi or weir.
The SGM-600F is suitable for flow measurement in partially filled pipes, drainage channels, man-made channels, waterways, drainage ducts, etc. The instrument is composed of a flow calculator, a speed transducer (with a doppler effect) and level. SGM-600F can display speed, level, flow rate and totalizer. It can record flow and total flow data on an SD card up to 16 GB.
SGM-600F can calculate the cross-sectional area of partially filled pipes, open channel or river, and up to 20 coordinate points can be entered to describe cross-section of the river or channel with irregular shape. The velocity and level transducer integrates in it the instruments for measuring water speed, depth and temperature.
SGM-600F is an indispensable instrument for flow measurement in all those applications where there is no hydraulic projection in the channel
or in the pipe.
Additional information
Case Material | Fibre Glass |
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Degree of Protection | IP66 |
Keyboard | 6 push buttons |
Display | LCD |
Electrical Connection | Internal push connectors |
Working Temperature | -20°C ÷ +60 °C |
Supply | 85 ÷ 265 Vac o 12 ÷ 28 Vdc |
Analog Output | n. 14 ÷ 20 mA, con carico min. 250 ohm e max 500 ohm |
Digital Communication | Modbus RTU (optional) |
Data Logger | 16 GB SD card |
Pipe/Channel Dimensions | Ø 300÷6000 mm / 200÷6000 mm |
Speed Range | 21 ÷ 4500 mm/s bi-directional |
Speed Resolution | 1mm/s |
Speed Accuracy | ±2% |
Speed Sensor | Signal trajectory: 30° above the horizontal |
Level Range | 0 ÷ 3000 mm o 0 ÷ 6000 mm |
Level Accuracy | ±0,25% |
Resolution | 1 mm (0 ÷ 1 m); 2 mm (1 ÷ 3 m), |
Range temperature | -17°C ÷ 60°C |
Resolution Temperature | 0,1°C |
Cable | 15 m std. (max 100 m opz.) |
Transducer Body Material | PVC / AISI (fixing plate) |

SGM-600P
Area velocity flowmeter
Flow measurements in open channels.
No need for a hydraulic primary.
4 ÷ 20mA analogue output (opt.)
MODBUS RTU communication port (opt.)
16GB SD card datalogger (opt.)
Battery autonomy 40h.
Up to 20 points for configuring the irregular profile of a channel.
The SGM-600P is suitable for measuring flow in partially filled pipes, drainage channels, man-made channels, waterways, drainage ducts, etc.
The instrument is composed of a flow calculator, a speed transducer (with a Doppler effect) and level.
SGM-600P can display speed, level, flow rate and totalizer.
It can record flow and total flow data on an SD card up to 16 GB. SGM-600P can calculate the cross-sectional area of partially filled pipes, open channel or river, and it is possible to input up to 20 coordinate points to describe cross-section of the river or channel with irregular shape. The velocity and level transducer integrates in it the instruments for measuring water speed, depth and temperature.
SGM-600P is an indispensable instrument for flow measurement in all those applications where there is no hydraulic projection in the channel or in the pipe.
Additional information
Case Material | ABS |
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Degree of Protection | IP65 |
Keyboard | 6 push buttons |
Display | LCD |
Electrical Connection | Connectors |
Working Temperature | -20°C ÷ +60 °C |
Supply | Rechargeable lithium batteries 12 Vdc 12 Ah, autonomy 40 hours, |
Analog output | (Optional), |
Digital communication | Modbus RTU (optional) |
Data Logger | 16 GB SD card, |
Dimension l x h x p (mm) | 270 x 215 x 175 |
Pipe / channel dimensions | Ø 300÷6000 mm / 200÷6000 mm |
Speed range | 21 ÷ 4500 mm/s bidirectional |
Speed resolution | 1mm/s |
Speed accuracy | ±2% |
Signal trajectory | Speed sensor: 30° above the horizontal |
Level range | 0 ÷ 3000 mm o 0 ÷ 6000 mm |
Level accuracy | ±0.25% |
Resolution | 1 mm (0 ÷ 1 m); 2 mm (1 ÷ 3 m), |
Range temperature | -17°C ÷ 60°C |
Temperature resolution | 0,1°C |
Cable | 15 m std. (max 100 m opz.) |
Transducer body material | PVC / AISI (fixing plate) |

BS VENTURI
BS Venturi hydraulic modeler
Installation in rectangular channels.
Flow rates 1 ÷ >7700 m3/h.
Low load losses.
Matching to all SGM-LEKTRA systems for flow measurement in open channels.
SGM-LEKTRA has developed its own flumes family called BS… in co-operation with the Pavia University Hydraulic Division. BS flume is a special Venturi with flat bottom and ready to be lodged in a pre-existing rectangular channel. BS VENTURI are suitable for use in irrigation systems, industrial waste water treatment, sewage, and in general for turbid waters; the flat bottom without protrusions has a self-cleaning effect, does not favor the debris deposit and can be easily inserted in rectangular ducts existing.
The submerged flow (ratio from downstream head and upperstream head) can be well tolerated. The practical limit of submergence for all sizes is about 90%.

CA400
Complete system for flow measurement
2 independent flow measurements
Measuring range of sensors 1.5; 6 meters
IP68 sensor protection
2 analogue outputs 4 ÷ 20mA
5 totally configurable relays
2 open collector digital outputs
2 analogue inputs 4 ÷ 20mA
2 digital inputs (max 24Vdc 10mA)
Datalogger on USB Pen Drive
The flow measurement in open channels with the hydraulic projection method is carried out with the use, inside the channel or partially filled pipe, of a hydraulic modeller (BS – venturi / PB channels – palmer bowlus), a probe for the Level measurement (in this case ultrasound (PTU50; PTU51, without contact with the liquid itself) and an associated control unit (VLW90M) VLW90M is suitable for a direct connection of 1 or 2 MODBUS ultrasound sensors. Thanks to this feature, the CA400 system is able to simultaneously perform two independent flow measurements with ultrasonic sensors and different hydraulic modellers for each type of channel. Logger “based on removable PenDrive, allows the total traceability of flow measurements in open channels for which it is very easy to analyze the time profile of the instantaneous flow rate.
CA400 with Palmer Bowlus
CA400 with BS Venturi Channels

Flow51
Compact flowmeter
Compact system suitable to be installed upstream from hydraulic modelers (weirs, venturi, palmer bowlus)
Excellent price-performance ratio
Istantaneous and totalized flow
measurement
Measure range 0.3÷6m
MODBUS communication protocol
IP68
FLOW51 is a compact IP68 ultrasonic flow transmitter, suitable for the installation in flood-prone wells. The measurement is based on the principle of the raising of the water level before restriction, which is used to calculate the value of instantaneous flow in relation of the type of the existing flume.
FLOW51 can be calibrated via MODBUS RTU or VLW601 if used with SGM LEKTRA Venturi flumes, Palmer Bowlus, Parshall flumes, Khafagi Venturi flumes and all the main types of weirs. In case of non-standard flumes the unit can be calibrated by following the linearization table present on the manual or by using a customized flow formula.
Additional information
Case material | Polypropylene (PP) |
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Assembly | 1”GAS M – PP flange DN100/125 opt. |
Degree of protection | Sensor: IP68 |
Electrical connection | IP68 male connector with 5/10/15/20m linking cable |
Working temperature | -25 ÷ +75°C |
Pressure | 0,5 ÷ 1,5 bar (absolute) |
Supply | 24 Vdc |
Absorbed power | 1.5W |
Analog output | 4÷20mA max 750ohm |
Digital communication | MODBUS RTU |
Measuring range | 0,3 ÷ 6m (distance sensor – water), |
Temperature compensation | digital from |
Accuracy | ±0,2% (of the measured distance) not better than ±1 mm |
Resolution | 1mm |
Calibration | VLW601 prog. module with 4 buttons or by Modbus |
Thermal stabilization | 30 minutes typical |
Visualization | matrix LCD display on VLW601 module (opt.) |

Flowmeter
Compact flowmeter
Compact system suitable to be installed upstream of hydraulic modelers (weirs, venturi, palmer bowlus).
Solution with excellent price performance ratio.
Instantaneous and totalized flow measurement.
No. 2 freely programmable relays.
MODBUS communication protocol.
Flowmeter is an ultrasonic flow transmitter, temperature-compensated and suitable for connection with MODBUS RTU acquisition systems.
Flowmeter in addition to an analog output includes two freely addressable relay for flow threshold or for totalizer pulse output.
Additional information
Case Material/sensor | PC or AI / PP or PVDF |
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Mechanical installation | 2”GAS M (flange in PP DN80 opz.) |
Degree of protection | IP67 / IP68 (sensor) |
Electrical connection | Terminals |
Working temperature | -20°C ÷ +60 °C |
Pressure | 0,5 ÷ 1,5 bar (absolute) |
Supply | 12 Vdc / 24 Vdc |
Absorbed power | 1.5W |
Analog output | 4…20mA, max 750 ohm |
Relay | n°2 3A 230 Vac (n.a.) |
Digital communication | Modbus |
Measuring range | max 0.25 ÷ 5 m Distances expressed are considered valid for surface measurements there perfectly, if not the maximum measurable distance is degraded |
Blocking distance | 0,25 m |
Temperature compensation | digital from -30 to 80°C |
Accuracy | ±0,2% (of the measured distance) not better than ±1 mm |
Resolution | 1mm |
Calibration | 4 buttons or via Modbus |
Thermal stabilization | 1 minute typical |
Visualization | VL611 programming module (opt.) with 4 keys and matrix LCD |

PB
Hydraulic modeler
For flow measurement in outflow pipe or no pressurized pipes
Direct installation in the pipe or manhole
Flow rates from 0,45 m3/h to 1800m3/h
Matching Sets with all SGM-LEKTRA open
channels flow measurement systems
Low cost system
Ideal to circular duct flowrate measure
Essentially a hydraulic modeler designed to increase, upstream of the restriction, the fluid head during its outflow. The Palmer-Bowlus upstream
fluid head, increases or decreases in function of the fluid quantity flowing over it.
The head measured by a level transmitter is then used to calculate the instantaneous flow rate value. The Palmer-Bowlus is mainly used in pipes or ducts accessible through the manholes.
The easy installation, and the contained installation cost, are the reason for the applications number increasing of this system to measure the flow rate.