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Protecting the GOLD of tomorrow TODAY


Water - clear, soothing, calming

...and above all, NEEDED FOR SURVIVAL! It is therefore all the more important to know where this
precious GOOD is moving in its pure and impure state and in what quantity.
Besides natural rivers and streams, it is managed systems, sewers and treatment plants,
where water authorities are demanding more monitoring of flow rates due to
due to recurrent droughts in recent years.

Dry land

There are non-contact measuring systems for determining these discharge
measuring systems with which this information can be easily collected.

Water purification - IMPORTANT

Water Cleaning

In addition to surface waters, part of our water balance consists of wastewater, which is professionally treated
in wastewater treatment plants to produce drinking water.

Drinking water

Why measuring systems with ATEX certification?


Speed and level measurement

Example: sewage treatment plant

During wastewater treatment in a sewage treatment plant, anaerobic decomposition processes take place in the digestion tower. This produces biogas (also known as sewage gas or digester gas), which consists mainly of methane and carbon dioxide.
The biogas is very moist, tends to condense and is loaded with particles. Its composition is variable and aggressive.
In combination with air, it can lead to explosive mixtures.
Therefore, appropriate safety measures must be taken. For example, the technical equipment used in this area must
be specially approved for the respective Ex zone.
An "explosion-protected" system is defined as a system requiring monitoring if it comprises all devices, protective systems, safety, monitoring or control devices as defined in the applicable country-specific directive and their functional interconnection.

ATEX - Fields of application

 ATEX ( ATmosphères EXplosibles ) protection is divided into zones 0-2

Sommer offers two different models for Ex Zone 1 and Ex Zone 2.


Speed measurement


Speed and level measurement

SQ-ATEX - short description 

Accurate and timely knowledge of the water flow is of central importance for the operation of sewage treatment plants and wastewater networks and the management of municipal and industrial water resources.
The SQ- ATEX sensor is a measuring device for continuous and non-contact measurement of water flow in hazardous areas.
It combines two devices in one system.The first determines the water level by measuring the time of flight of a radar signal, the second the flow velocity of the water surface by means of Doppler frequency shift.
After each measurement, the sensor uses a powerful and hydraulic model to calculate the average velocity and the wetted cross-sectional area, which in turn are used to calculate the water discharge.

  • Non-contact radar measurement prevents contamination and damage
  • Automatic flow calculation based on a hydraulic model with several k-factors
  • Sensor self-checking with status and error output
  • AI-based machine learning enables environmental influences to be compensated and errors to be detected at an early stage
  • 3-point calibration certificate for velocity
  • Advanced velocity diagnostics with display of spectra
  • Flow calculation in SQ
  • Level and velocity sensor integrated in one housing protected from weather and vandalism

Further information on our website:


Questions? contact us:

SQ-ATEX – Sample installation situation

Accurate and timely knowledge of water flow is central to the operation of wastewater treatment plants and networks and the management of municipal and industrial water resources.


Installation example: SQ-ATEX mounted on a mobile shaft suspension with cable feed-through of the sensor to the 3 ATEX barriers in the control cabinet of the data logger.


Wiring example: SQ-ATEX via barriers on MRL-8 4G data logger


Questions? contact us:

SQ-ATEX – plug and play

The SQ-ATEX has an attractive price-performance ratio and, on request, comes pre-set OUT of the box ready for connection. 


The installation can be carried out by the in-house ATEX representative or by an external company approved for this purpose,
which also knows the country-specific regulations.

After mechanical installation and electrical connection, commissioning can be carried out by the customer with
remote maintenance support by Sommer technician.

SOMMER MDS 2.0 example with 2G/3G/4G,Ethernet or LORA
data transmission incl. data backup for up to 36 months

Related products


The SQ-R continuously and contactlessly measures the flow rate of sewers, partially filled pipes and technical flumes in industry and water supply. The SQ-R is not in contact with the water and can therefore be operated without being affected by dirt and solids and can therefore be operated without being affected by dirt and entrained solids.
With its compact design and versatile mounting options, it is the ideal choice for flow measurements in maintenance shafts of plants and sewers.

The PQ continuously measures the flow of water or wastewater in sewers, pipes and open channels in sewer networks, water treatment plants and industrial facilities.
It combines two sensors in one system.
The first determines the water level with a pressure probe or a radar sensor, the second simultaneously measures the average flow velocity with an ultrasonic Doppler sensor.

The PV SOMFLOW continuously measures water or discharge velocity in sewers, pipes and open channels in sewer networks, water treatment plants and industrial facilities.
The dual 1 MHz ultrasonic Doppler transceiver detects flow velocities from as low as 0.01 m/s to 5 m/s.


About us

Sommer develops and distributes sensors and environmental monitoring equipment, including system solutions for data acquisition, data transmission and analysis of the acquired data, as well as customised safety / monitoring gear systems. With more than 30 years of experience. SOMMER is a true measurement specialist and reliable partner in hydrography, meteorology, industry and water management, wastewater and for geotechnical applications.

Innovative Doppler radar sensors for discharge measurement, unique snow monitoring technology as well as user-friendly systems for data management and telemetry testify to the company's distinctive innovative spirit. The realisation of monitoring systems far away from any infrastructure and in harsh environments, such as alpine and high alpine weather stations, forms another field of experience of SOMMER.

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Sommer GmbH
Tel +43 5523 55989
Strassenhäuser 27
6842 Koblach

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