Open Channel Flow Meter Supplier in Bangladesh
Nivelco ultrasonic open channel flow meters from Hungary for effluent, sewage and clean water channels, supplied with installation and after-sales support by Techno Bangla Creation.
What Is an Open Channel Flow Meter?
An open channel flow meter measures how much liquid flows through a channel, drain or flume that is open to the air. An ultrasonic sensor above the water sends sound pulses to the surface and times the echo to find the water level. The meter then converts that level into flow rate, using the shape of a flume or weir.
An open channel flow meter is not a pipe flow meter. Electromagnetic and vortex meters are built for pipes that run full, while an open channel meter works where liquid runs partly full with a free surface, such as the outlet channel of an ETP.
- Non-contact ultrasonic level sensing, so the sensor stays out of the effluent
- Level converted to flow for a flume or weir
- Multicont controller with EasyTREK / EchoTREK transmitters
- Suited to clean water and waste water channels
- Installation and after-sales support in Bangladesh
Open Channel Flow Meter Specifications
- Type
- Ultrasonic, non-contact open channel flow meter
- Models
- Multicont controller with EasyTREK / EchoTREK ultrasonic transmitters
- Principle
- Ultrasonic time-of-flight level measurement, converted to flow for a flume or weir
- Measuring range
- EasyTREK and EchoTREK transmitters reach up to 25 m (about 82 ft), depending on model
- Beam angle
- About 5 to 7 degrees (full beam angle of SenSonic transducers)
- Output
- 4 to 20 mA with HART communication, depending on model
- Primary device
- Parshall flume, weir or another structure with a known level-to-flow relationship
- Application
- Clean water, waste water (ETP, STP and WTP channels)
- Brand
- Nivelco
- Origin
- Hungary
Exact range, accuracy, power supply, housing and output depend on the model you select. Confirm values on the datasheet of the exact model. Send us your channel size and flow range and our engineers will confirm the right Nivelco model.
Ultrasonic vs Radar vs Area-Velocity Flow Meters
Three common ways to measure flow in an open channel. Each suits different sites.
| Feature | Ultrasonic Level (Nivelco) | Radar Level | Area-Velocity |
|---|---|---|---|
| How it measures | Sound pulses time the distance to the water surface. Level is converted to flow. | Radar waves time the distance to the water surface. Level is converted to flow. | Measures level and water velocity, then multiplies area by velocity (Q = A × V) |
| Flume or weir needed | Yes | Yes | No |
| Foam, steam and condensation | Can disturb the echo. Shade the sensor and keep the surface clear. | Reported to be much less affected | Surface foam does not block it, but silt, fouling and aerated flow can upset velocity readings |
| Temperature and wind | Sound speed changes with air temperature. Strong wind or temperature gradients can affect readings. | Reported to be largely unaffected | Submerged sensor sits in the flow, not in the air |
| Submerged or surcharged flow | Flume accuracy is lost if downstream water submerges the flume | Same limit as ultrasonic, because the flume is the same | Can work in partly full and surcharged pipes, depending on model |
| Maintenance | Sensor stays out of the water. Keep the sensor face clean and the flume free of debris. | Sensor stays out of the water | Submerged sensor needs periodic cleaning |
| Initial cost | Generally lower than radar | Generally higher than ultrasonic | Depends on model. No flume to build. |
| Best fit | ETP, STP and WTP channels with a flume or weir, sheltered from steam and heavy foam | Outdoor or steamy channels and heavy foam | Existing sewers and channels with no flume, or with backwater |
Values are typical figures reported in public engineering guidance and manufacturer notes. Always confirm against the datasheet of the exact model. Other suppliers in this space include Siemens (SITRANS LUT400 ultrasonic controllers), KROHNE (80 GHz radar level for flumes) and Greyline (area-velocity meters). We supply the Nivelco ultrasonic range.
How Does an Open Channel Flow Meter Work?
- Sensor Sends a Sound PulseThe ultrasonic transmitter above the channel sends a burst of sound toward the water surface.
- Echo ReturnsThe surface reflects the sound back, and the electronics time the trip.
- Time Becomes LevelFlight time becomes distance, and distance becomes water level above the flume floor or weir crest.
- Level Becomes FlowThe meter applies the head-to-flow relationship of the Parshall flume or weir to get the flow rate.
- Signal Reaches Display or PLCA 4 to 20 mA or HART signal feeds the Multicont display, a PLC or a recorder.
Why Use an Ultrasonic Open Channel Flow Meter?
A flow record is a basic part of any ETP or STP that discharges treated water.
- Non-contact sensing: the transmitter stays above the effluent, away from solids, grease and chemicals
- Works with standard primary devices such as Parshall flumes and weirs once the head-to-flow relationship is set
- Narrow beam of about 5 to 7 degrees and ranges up to 25 m on EasyTREK and EchoTREK models
- 4 to 20 mA and HART communication, with Multicont for display and multidrop connection
- Suited to both clean water and waste water channels
- Local engineering and after-sales support from Techno Bangla
Which Open Channel Flow Meter Fits Your Channel?
Choose an Ultrasonic Meter When
- You have, or can build, a Parshall flume or weir with free-flowing discharge
- The channel is open to the air and fairly sheltered from steam, spray and strong wind
- The flow carries solids, grease or chemicals that would foul a submerged sensor
- You want a lower upfront cost than radar for a predictable site
- You need a flow record for ETP or STP discharge reporting
Choose Another Technology When
- Heavy foam, steam or condensation covers the channel. Ask us about a radar level option.
- The line runs as a full pipe. See our electromagnetic flow meter.
- A flume is not possible, or the channel often backs up or surcharges. Consider an area-velocity meter.
- Downstream water often submerges the flume
- You only need level or volume in a tank or sump, not flow
Where Are Open Channel Flow Meters Used?
Any channel, drain or flume where liquid flows with a free surface.
- ETP Inlet Channel
- ETP Outlet Channel
- STP Effluent Channel
- Textile and Dyeing Mills
- Pharmaceutical Plants
- Food Processing Plants
- WTP Raw Water Channel
- Canals and Drains
- Sumps and Lift Stations
How to Choose an Open Channel Flow Meter
Share these details with our engineers and we will recommend a suitable Nivelco model and setup.
- Primary device. Decide between a Parshall flume and a weir. Flumes suit flows with solids and lose less head, while weirs suit clean, low flows but tend to trap solids. Size it for your minimum and maximum flow, because accuracy below the minimum head is questionable.
- Sensor position. Mount the sensor at the measuring point the flume specifies. Moving it upstream or downstream makes the meter over-read or under-read. Keep it above the highest level plus the sensor's blocking distance.
- Steam, foam and heat. Dyeing, washing and hot effluent in Bangladesh's humid climate can create steam and foam. Shade the sensor, keep the sound path clear, and ask about radar if foam is heavy.
- Free flow or backwater. Keep the flume free-flowing. If downstream water often submerges it, a single level reading is no longer enough.
- Output and display. Tell us whether you need 4 to 20 mA, HART or a Multicont display, and how far the signal must travel to your PLC or panel.
Why Does Effluent Flow Data Matter in Bangladesh?
Bangladesh's Environment Conservation Rules 2023 took effect on 5 March 2023 and replaced the 1997 rules. Textile dyeing mills fall in the red category, which must run an ETP. A reliable flow record shows how much effluent the plant actually treats and discharges.
The Department of Environment's enforcement guidelines also refer to the factory's flow meter reading, or a portable meter reading, when they work out wastewater flow. Flow data can also pace chemical dosing. See our chemical dosing pump and online analyzer pages. Check the exact requirement for your category with the Department of Environment.
Installation and After-Sales Support
Techno Bangla Creation supplies treatment plant equipment together with installation, commissioning and after-sales support for factories, businesses and organizations across Bangladesh.
Our team is based in Mohakhali, Dhaka. Send your channel details and our engineers will recommend a suitable Nivelco open channel flow meter. See the ETP plant page for complete plant solutions, or browse all flow meters.
Frequently Asked Questions
What is an open channel flow meter?
An open channel flow meter measures how much liquid flows through a channel, drain or flume that is open to the air. An ultrasonic sensor above the water sends sound pulses to the surface and times the echo to find the water level. The meter then converts that level into flow rate, using the shape of a flume or weir.
How does an ultrasonic open channel flow meter work?
An ultrasonic transmitter above the channel sends sound pulses to the water surface and times the echo. The electronics turn that time into water level, then apply the head-to-flow relationship of a flume or weir to calculate flow rate. The result leaves as a 4 to 20 mA or HART signal to a display or PLC.
Do I need a flume or weir for an open channel flow meter?
Yes, for level-based flow measurement. The sensor reads water level only, so a flume or weir must create a known relationship between level and flow. Parshall flumes suit wastewater with solids and lose less head, while V-notch weirs suit clean, low flows. Our engineers can advise on sizing for your channel.
How accurate is an ultrasonic open channel flow meter?
Accuracy depends mainly on the flume or weir and how well it is installed. A Parshall flume in good condition is generally quoted at about ±5% in the field (ASTM D1941), and EPA training material refers to about ±10% of actual flow for effluent systems. Check the sensor accuracy on the datasheet of the exact model.
Ultrasonic vs radar vs area-velocity: which should I choose?
Ultrasonic suits sheltered channels with a flume and generally costs less. Radar is reported to cope better with foam, steam and temperature swings but usually costs more. Area-velocity meters need no flume and work in surcharged pipes, but submerged sensors need cleaning. Tell us your site conditions and we will recommend one.
Is it suitable for a textile ETP in Bangladesh?
Yes, ultrasonic meters are used on wastewater channels when the site suits them. Hot, humid dyeing effluent can create steam, condensation and foam that disturb ultrasonic echoes, so shade the sensor and keep the sound path clear. For heavy foam, ask us about a radar option. Our engineers check this during selection.
What is the difference between an open channel and an electromagnetic flow meter?
An open channel flow meter measures liquid flowing with a free surface, such as in a drain or flume, by reading water level. An electromagnetic flow meter measures liquid that completely fills a pipe. Choose by how your line runs, and ask us if you are unsure.
How much does an open channel flow meter cost in Bangladesh?
Price depends on the Nivelco model, measuring range, outputs and display, and on whether you also need a flume or weir. Send your channel width, flow range and site conditions to our engineers by phone or email, and we reply with a free quotation. Photos of the channel help.
