Starting at $3,175.00

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  • For open channels and pipes
  • No flume or weir required
  • Measures velocity + level to calculate flow
    • 0.1 to 20 ft/sec & reverse flow to -5 ft/sec velocity
    • 1 inch to 15 feet level range
  • Works in partially filled and surcharged pipes
  • Measures forward and reverse flow
  • 3 Isolated 4-20mA outputs (Flow, Level and Velocity)
  • Totalizer and 2 control relays
  • Optional intrinsically safe sensor
  • Optional built-in 2-million point data logger
  • Simple 5-key calibration

What's in the Box

  • Submersible velocity & level sensor
  • Submersible, shielded 3-coaxial cable
  • Stainless steel sensor mounting bracket
  • Installation and operation manual

The Greyline Instruments AVFM 5.0 ultrasonic flow meter is designed to display, transmit and totalize flow through open channels, partially filled pipes and surcharged pipes without a flume or weir making it ideal for municipal stormwater, combined effluent, raw sewage and irrigation water applications.

The AVFM 5.0 ultrasonic flow meter measures both level and velocity to calculate flow in an open channel or pipe. The meter can measure forward flow velocity up to 20 ft/sec (6 m/sec) and reverse flow up to 5 ft/sec (1.5 m/sec). The electronics and software sample and average flow rates continuously to provide stable readings. The submerged velocity/level sensor is suitable in pipes with pressure up to 10 psi. No special set-up or adjustment is required. Minimum recommended pipe diameter is 6" (150 mm).

Setting up and using the AVFM 5.0 is simple. The ultrasonic sensor mounts inside the pipe or on the bottom of a channel with a stainless steel mounting bracket and a single screw into the bottom of the pipe or channel. No special compounds, tools or hardware are required. The sensor is completely sealed with no orifices or ports. Careful selection of sensor mounting location results in best performance and maintenance-free operation. Locations where sediment builds up should be avoided. Best possible accuracy will result when the water is not highly turbulent and where velocity is evenly distributed across the channel. The channel should not have drops or direction changes immediately upstream of the sensor mounting location. Pipe or channel slope should not exceed 3%.

The flowrate and total flow can be viewed on the AVFM 5.0's large backlit LCD display. The unit can be connected to external devices with three 4-20mA outputs and two control relays. Choose the built-in data logger option if you want the AVFM 5.0 to store time and date stamped flow values at 10 second to 60 minute intervals. Daily flow reports are automatically created. Windows software is included to display log files in graph and table formats, change measurement units and generate flow reports.

Calibration is as simple as entering the pipe diameter or channel dimensions and letting the AVFM 5.0 automatically compute and display flow volume.


Greyline Instruments VXC Sensor Cable
Submersible, tri-coaxial cable available in lengths up to 500 feet


Greyline Instruments QZ02L-DP Velocity Sensor
Submersible ultrasonic sensor continuously measures stream velocity in the channel
In Stock
Greyline Instruments PZ15-LP Level Sensor
Low profile, non-contacting ultrasonic level sensor ideal for confined spaces and small flumes
Greyline Instruments PZ15 Level Sensor
Non-contacting ultrasonic level sensor is small enough for very small flumes and powerful enough for really large applications.


Please consider these optional accessories.

Greyline Instruments VD Series Pipe Dams
Maintains low flow water level at 1” or higher as required for ultrasonic level measurement.
Greyline Instruments VSJ Series Mounting Bands
Provides easy mounting for submersible sensors inside of round pipes
Greyline Instruments JB2X Sensor Cable Junction Box
NEMA4X/IP66 polycarbonate junction box for extending sensor cable lengths
Greyline Instruments QZ02L-SS-SD Velocity & Level Sensor
316 stainless steel submersible ultrasonic sensor, continuously measures both velocity and level in the channel
Greyline Instruments CHS Spare Electronics Set
Spare set electronics with mounting chassis (standard features)


This product can be used in the following applications:

Application Notes

Here's how some of our customers used this product.

Measuring the Volumetric Flow in Large, Partially-filled Pipes

The Background: A wastewater treatment plant requires volumetric flow records of all incoming and outgoing water, treated or otherwise.

The Problem: The influent is directed from a 72-inch sewer main which is typically just 5 to 15% filled so as not to cause restrictions which could back-up the entire sewer system upstream. The challenge, then, is measuring the flow in this large, partially filled pipe.

The Solution: The Greyline AVFM ultrasonic flow meter can calculate flow in an open channel or pipe making it a great solution that is simple and easy to install. Simply program in the pipe’s geometry and a level sensor measures the fluid depth while an angled Doppler ultrasonic sensor measures fluid velocity. These two values allow the meter to calculate the cross-sectional area that the water is occupying and the volumetric flow.

Part Number Price Available
AVFM 5.0A-1-A-1-B1-1-B-1-A
Show Configuration
Base Price
Power Input
Standard, 100-240VAC 50/60Hz
Standard, NEMA4X (IP66) fiberglass
Enclosure Temperature
Standard, -5 to 140°F (-20 to 60°C)
Electronics Protection
Standard, no circuit board coating
PZ15-LP non-contacting level plus QZ02L-B submersible velocity (+$250.00)
Intrinsic Safety Barriers
Standard, general purpose locations, not rated Intrinsically Safe
Sensor Cable Length
50 ft. submersible, shielded 3-coaxial (+$110.00)
Data Logger
Standard, without
Control Relays
2, standard
$3,535.00 1

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