Open Channel Flow Meter

Product Description

An open channel flow meter is used to measure the flow rate of liquids in open conduits, such as rivers, canals, weirs, flumes, and partially filled pipes where there is a free surface. Unlike closed-pipe flow meters, open channel flow measurement often relies on inferring the flow rate based on the liquid level and the channel's geometry.

Here's a breakdown of typical specifications for an open channel flow meter, categorized by the measurement principle:

Common Measurement Principles and Their Specifications:

1. Level-Based Flow Meters (with a Primary Device): These meters measure the liquid level and use a known relationship (e.g., a formula based on the geometry of a weir or flume) to calculate the flow rate.

• Level Sensor Type:
  • Ultrasonic Level Sensor:
    • Measurement Range: The minimum and maximum liquid level the sensor can measure 
    • Accuracy: The accuracy of the level measurement  of the measured distance).
    • Resolution: The smallest change in level the sensor can detect
    • Operating Frequency: The ultrasonic frequency used by the sensor.
    • Beam Angle: The angle of the ultrasonic beam.
    • Temperature Compensation: Ability to compensate for temperature variations affecting the speed of sound.
    • Output Signal: Analog digital (e.g., RS485 with Modbus).
    • Ingress Protection (IP Rating): Environmental protection rating of the sensor.
  • Submersible Pressure Sensor (Hydrostatic Level Sensor):
    • Measurement Range (Depth): The maximum depth the sensor can measure 
    • Accuracy: The accuracy of the pressure/level measurement
    • Output Signal: Analog
    • Temperature Compensation: Built-in temperature compensation for accurate readings despite fluid temperature changes.
    • Cable Length and Material: Length and chemical resistance of the sensor cable.
    • Sensor Material: Material of the sensor body and diaphragm
    • Ingress Protection (IP Rating): Environmental protection rating of the sensor.
  • Radar Level Sensor (Non-Contact):
    • Measurement Range: The minimum and maximum liquid level the sensor can measure
    • Accuracy: The accuracy of the level measurement of the measured distance.
    • Operating Frequency: The radar frequency used by the sensor.
    • Beam Angle: The angle of the radar beam.
    • Output Signal: Analog  digitalIngress Protection (IP Rating): Environmental protection rating of the sensor.
  • Float and Encoder Systems:
    • Measurement Range: Determined by the length of the float arm or cable.
    • Accuracy and Resolution: Dependent on the encoder's specifications.
    • Output Signal: Analog or digital depending on the encoder.
• Primary Device (Weir or Flume):
  • Type: V-notch weir, rectangular weir, trapezoidal weir, Parshall flume, Palmer-Bowlus flume, etc.
  • Size and Dimensions: Specific dimensions according to standard designs or application requirements.
  • Material of Construction: Stainless steel, fiberglass, concrete, etc., depending on the application and fluid.
  • Accuracy of Construction: Adherence to precise dimensional tolerances is crucial for accurate flow rate calculations based on level measurements.
  • Head-Discharge Relationship: The specific formula or calibration curve that relates the measured liquid level (head) to the flow rate for the chosen primary device.