Kanalis TT

Transit Time Flow Meter for flow measurements in Open Channels

Kanalis TT ultrasonic flowmeter for open channels


Acoustic Paths 1 – 8, length 1 – 30 m
Frequency 200 kHz
Range ± 20 m/s, bi-directional
Accuracy ± 2% (typical)
Display 4 lines, 20 characters
Datalogger internal,
sampling interval user selectable
Communications RS-232, MODBUS, Ethernet, USB
Inputs max. 8 x 4-20 mA
Outputs max. 4 x 4-20 mA

2 x Relay, 2 x Pulse

Power Supply 85-264 VAC (50-60 Hz)
or 12 VDC
Battery Backup integrated, 2 Ah
Enclosure Steel, wall mounted
Dimensions 400x500x160mm (WxHxD)


TD-200/18, TD-200/8, TD-200/18-ATEX





Frequency  200 kHz  200 kHz  200 kHz
Bandwidth  18° (-3dB)  8° (-3dB)  18° (-3dB)
Dimensions  Ø 140 mm,

Height 70 mm

 Ø 218 mm,

Height 109 mm

 Ø 140 mm,

Height 70 mm

Mounting Assembly

Standardized mounting devices for any kind of channel geometry like rectangular, trapezoid or natural river banks are available. The design is flow optimized protecting the transducers against moving objects suspending in the flow stream. It also provides room for connections and protective conduits.

 Single-, Crossed- & Multi-path Systems

  • A cross-section view of a 1 plane transducer configuration
    Transit Time - 1 Plane

Single-path system

In its most basic form, the ultrasonic gauge operates with a single pair of transducers.

However, it relies upon a relatively stable velocity profile, essentially unaffected by changes in the relation between water level and flow.

The main flow has to be parallel to the bank. The relationship between measured velocity and discharge is established by hydrometric calibration.

Kanalis TT single path ultrasonic flowmeter for open channels

 Crossed-path system

In rivers there is a high risk of cross flow. Its intensity depends mainly on the river’s geometry and if there is an upstream bend in the river.

Although the cross flow does not influence the quantity of the discharge, it may affect the measurement, a second pair of transducers will be necessary.

By crosswise arrangement of four transducers, effects of changing flow direction can be eliminated.

Kanalis TT crosses path ultrasonic flowmeter for open channels

 Multi-path system

An even more accurate discharge measurement can be obtained with systems using several planes.

The measured result can be further improved by using a multi path system layering each of the acoustic paths in parallel planes one above the other. This negates having an expensive hydrometric calibration.

This type of system is suitable for applications with large water level fluctuations, reverse flow or a vertical velocity distribution outside the theoretical normal.

Kanalis TT multipath ultrasonic flowmeter for open channels
Rivers Thumb