TF Stationary flow measurement partially filled

Ultrasonic transit time difference measurement with dry weather gutter

Precise and cause-related flow measurement

The TF Stationary Flow Measurement is a calibrated measuring channel for backflow-free flow measurement of wastewater, raw wastewater and rainwater in open channels or open channels. The need for a cost accounting based on the polluter-pays principle is also increasing in the wastewater industry. Especially in view of increasing demands for precise measurement and control technology, the STEBATEC measuring system offers significant advantages to stationary, partially filled flow measurement.

Reliable measurement results – thanks to dry weather gutter

Because flowmeters are often unable to measure low water levels, the precise measurement of very small quantities in wastewater flow measurement technology is generally considered a challenge. Therefore, the purpose of STEBATEC’s adaptable flume design is to provide a device to measure flow rates in partially filled (open) sections, e.g. flumes, but also in closed sections, e.g. pipes, even at (very) low discharge. Thanks to the “dry weather gutter” on the partially filled stationary flow measuring system, water level and flow velocity remain measurable even in these cases. In addition, the dimensioning of the rainwater weather channel can also be carried out individually, so that the device cross-section can be adapted to the accruing water quantities, resulting in optimal measuring conditions. The rectangular shape was chosen in order to position the sensors close to each other and thus ensure a seamless, deep insight into the flow profile.

Three different construction methods

The stationary flow measurement partially filled TF is offered in the following three versions:

  • Wet exposition; open at the top and without drain-side connection to the continuing line
  • dry installation; closed with maintenance openings
  • In-line construction; in pipes and ducts with a diameter >1.5m
Inline design TF stationary flow measurement partially filled
TF stationary flow measurement Inline design in storage channels
TF stationary flow measurement in open channel as calibrated measuring section

Technical information

The partially filled stationary flow measurement was designed for integration into existing structures. Not only can the channel shape be adapted to the water volumes produced, but various adapters are also available for connection to the existing infrastructure. (See document: Technical documentation)

Ultrasonic flowmeters measure the velocity of a flowing medium using acoustic waves. In simple terms, two boats crossing a river diagonally on the same line; one in the direction of flow and the other against the flow. The boat that moves in the direction of the current takes a much shorter time to reach the opposite bank. The same applies to ultrasonic waves. A sound wave propagates faster in the flow direction of the medium to be measured than the sound wave in the opposite direction. The travel times are measured continuously. The transit time difference between the two ultrasonic waves is thus directly proportional to the average flow velocity. The flow volume per time unit is the result of the average flow velocity multiplied by the respective pipe or channel cross section. Acoustic flow measurement offers some advantages over other measurement methods. The measurement is largely independent of the properties of the media used, such as electrical conductivity, density, temperature and viscosity. The absence of moving mechanical parts reduces maintenance and there is no pressure loss due to cross-sectional narrowing. A large measuring range is one of the further advantages of this method.

Local conditions such as hydraulics, duct roughness and duct gradient do not influence the measuring accuracy, because the calibrated measuring channel provides ideal hydraulic conditions for specific measurements. In combination with sensor technology, which is difficult to manipulate due to solids and deposits, an optimal measuring quality is achieved.


Accurate measurement and easy to maintain

  • Guaranteed and controllable measuring accuracy >99%.
  • Self-calibrated measuring section
  • Reliable, very difficult to manipulate and influence by solids, deposits or external influences
  • Also works in backwater
  • Maintenance and cleaning is easy, as the unit is open at the top or easily accessible via maintenance openings.
  • Backwater protection, emergency overflowLong service life – no wearing parts
  • Fits mostly into existing buildings – no conversion necessary
  • Wide measuring range due to individually adaptable channel shape
  • Installation without water detour possible
  • Assembly usually possible in 1 day


Versatile – for communities and companies

  • Nominal sizes Wet and dry installation: NW200 to NW1200
  • Nominal sizes in-line construction: NW1500 to NW3000
  • Mounting with suspension adapter or slide plate adapter for easy removal for maintenance work
  • Quantity recording in municipal waste water special purpose associations
  • Quantity measurement on sewage treatment plants inlet and outlet side
  • Waste water outflow control for industrial plants
  • Measurement of drainage water
  • Mining and process water measurements in mining and tunneling
  • Cost accounting measurement
  • Extraneous water measurement
  • Rainwater measurement

References to this product

Let us advise you.

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