Flow meter untuk pipa tidak penuh

Open Channel Flow Meter: Definition, Working Principle, and Application

‎Open Channel Flow Meter which this time we discussed is one of the various types of flow meters whose use to measure the capacity of medium or large alira in the channel or trench.‎

‎Definition of Open Channel Flow Meter‎

‎Open Channel Flow Meter is a flow meter that is applied to measure medium or large flow capacity on a channel or trench. In practice, many are also used for rivers and culverts with super large sizes.‎

Open Channel flow meter
Ultrasonic flow meter open channel

‎Definition of Open Channel Flow Meter‎

‎The use of open channel flow meters in a stream with an open system and usually flow due to the force of gravity. The workings of this type of open channel flowmeter is to calculate the flow speed and surface height calculated against the cross-sectional area of the channel.‎

‎For the measurement of flow speed, ‎‎flow sensors‎‎ are used or calculate flow capacity based on delta pressure due to differences in water surface height.‎

open channel ultrasonic flow meter

‎So the basic principle of this ‎‎type of flow meter‎‎ is a combination of 2 types of height and speed sensors. To take measurements of the surface of the water can use a level sensor. As for the measurement of flow velocity can use magnetic flow sensor or ultrasonic flow sensor.‎

‎With the calculation of velocity the result of flow sensor installed against the cross-sectional channel area will be able to flow capacity. The flow capacity of open channel flow meters is called flow rate or flow discharge with units of volume per time.‎

‎Also Read: ‎‎Flow Meter To Measure Discharge on Open Channel‎

‎In general, this flow meter is classified on the type of ultrasonic flow meter. How this flow meter works as a way ultrasonic flow meter but combined with a level sensor. Where this level sensor can use a type of ultrasonic level or radar level.‎

‎Working Principles of‎
‎ Open Channel Flow Meter‎

‎Open channel flowmeters work at several points in the flow measurement path. The liquid may be fully open to the atmosphere, or it may be contained in a closed pipe that is not filled with liquid and only opens to the atmosphere at the installation point of the flowmeter itself. Open channel flow meters use two types of height sensors and velocity or height differences.‎

Flow meters for pipes are not full
‎Ultrasonic Flow Meter on Sewer Pipe‎

‎Basically this flow meter calculates the flow speed taking into account the height of the surface. For the measurement of flow speed can use transit time flow meter or magnetic flow meter. As for the surface height of the flow using ultrasonic level sensors. The incorporation of velocity with a cross-sectional area can result in flow rate flow capacity in the channel.‎

‎Classification and Examples of Open Channel Flow Meters‎

‎Open channels have actually often been found in everyday life so we must be familiar. Here is the classification of open channels based on their formation:‎

  • ‎Natural channel‎
    • ‎Natural channels are channels made naturally by nature. ‎
      ‎For example: Small rivers in the upstream area (mountains) to large rivers in the estuary.‎
  • ‎Artificial channel (artificial channel)‎
    • ‎An artificial channel is a channel that is intentionally made by humans. ‎
      ‎For example: Roadside drainage channels, irrigation canals for irrigating rice fields, sewers, sewers to carry water to hydroelectric plants, channels for drinking water supplies, flood drains.‎

‎In addition to the above classifications, open channels are also distinguished based on the consistency of cross-sectional shapes and basic lines.‎

  • Saluran Prismatic (prismatic channel)
    • ‎Prismatic channels are channels that are cross-sectional and the base slope is fixed. ‎
      ‎Example: Drainage channels, irrigation canals‎
  • Saluran non Prismatic (non prismatic channel)
    • ‎Non prismatic channels that are cross-sectional and the base slope is variable. For example: The river‎


  • ‎Simple to determine the flow with the right equation‎
  • ‎Long operational life‎
  • ‎Easy “out of water” sensor treatment‎
  • ‎Technology that has been tried and tested‎
  • ‎Suitable for dangerous areas‎
  • ‎Suitable for wastewater, debris-laden water and also corrosive media‎
  • ‎There are no moving or smooth parts in the stream itself.‎
  • ‎Cleaning yourself (flume)‎


  • ‎The device should be installed in a flow stream at a location where there is no disruption of deafness flow by upstream or downstream blockages.‎
  • ‎Requires a consistent flow profile‎
  • ‎Ongoing installation and maintenance costs of key devices‎
  • ‎Specific restrictions on the size and level of pipes/ducts‎
  • ‎The original form of the main device may experience wear/erosion/damage causing potential measurement inaccuracies over time‎
  • ‎Sedimentation, dirt, and other impurities can sometimes accumulate at the bottom of these devices, affecting the accuracy of level measurements.‎

‎Open Channel Flow Meter application‎

  • ‎Permanent and portable sewer monitoring program‎
  • ‎Wastewater treatment plant‎
  • ‎Measurement of industrial processes‎
  • ‎Irrigation canals‎
  • ‎Waste flow measurement‎
  • ‎Spill monitoring‎
  • ‎Combined Sewer Flow (CSO)‎
  • ‎SewerAge Sanitation (SSO)‎
  • ‎Event Duration Monitoring (EDM)‎

‎Also Read: ‎‎Type of Meter Level: Definition, Function, and How It Works‎

‎Thus the article on “Open Channel Flow Meter: Understanding, Working Principles, and Applications” hopefully can help all questions in your mind (readers), and hopefully can add insight from the unknown, hopefully useful.‎