IST mass flow sensors can be found in various flow switches, controllers or meters as well as the heart of leakage or bubble detection systems. Our mass flow sensor elements utilize thermal measurement principles known for their long-term stability and ease of integration into any application with a known fluid. From the physical sensor level to a ready-to-use digital module, build your custom flow sensor with IST AG. Evaluation kits are available with the most common flow sensors.


Very flexible and a good partner for customer specific solutions!

Answer from Customer Satisfaction Survey 2021

Sensor finder

Find the right flow sensors or module for your product!

Gas flow sensor elements

Gas flow sensor elements

Flow Sensor MFS

Using accurate thin-film heating and temperature sensing structures ensures high sensitivity with a very compact and robust sensor. The dynamic range of anemometric gas flow sensors ranges up to 100m/s covering operational temperatures up to +400°C.

The FS7 (link to product in shop) is our most widely used gas flow sensor for applications with a known flow direction.  The option of a simple housing keeps assembly into various flow channels easy to handle, and  its excellent long-term stability makes the flow sensor ideal for control and safety applications.

With FS2 and MFS02 sensors, flow direction can be monitored along with the measured mass flow. Their extra wide dynamic range make them excellent candidates for applications ranging from medical microfluidics to large scale HVAC systems. Different assembly options with cable, carrier PCB or custom housing ensure optimal sensor positioning.

SFS01 is a silicon based* calorimetric flow sensor with an ultra-fast response time suitable for medical and industrial flow applications with low flowrates and a mild temperature range. 


*Silicon technology

With the growing demand of miniaturization, the requirements of MEMS systems for ever smaller and thinner sensors met with our continuously expanding portfolio of silicon-based MEMS sensors.

Flow sensors

Flow sensors
for gases and liquids

An introduction into IST AG's flow sensor portfolio: depending what you need to measure, from low flow rates over fast response time to flow direction, we have the right solution for your application's needs.

Liquid flow sensor elements

Liquid flow sensor elements

OOL Flow sensor

OOL stands for out of liquid and is a flow-through sensor with stainless steel as single wetted material. This robust anemometric sensor is suitable for various aggressive liquids including coolant mixtures, oils containing particles or cleaning chemicals used in CIP systems.

The highly accurate and reliable OOL liquid flow sensor is suitable for measuring liquid flow in aggressive liquids. A heater and a temperature sensor chip, both with backside metallization, are soldered on the stainless-steel flow channel, providing an excellent thermal contact with the liquid without being in direct contact with it. For fast measurement results, there is an out of liquid demo board available.

Flow modules

Flow modules

Flow Modul OOLmass-flow-modul


The OOL Mass flow meter is a digital module continuously monitoring mass flow and temperature. It comes in a sturdy housing with a factory calibration as a plug-and-play sensor solution.

IST's leakage detection Flow OOL-module is equipped with a highly sensitive flow sensor component, which can detect the smallest liquid flow quantities with an accuracy of <3% F.S. and a repeatability of < 0.3 % F.S. (value for DI-H2O in temperature range of +5 to +50°C) in a response time of 500 ms.

Suitable for a wide variety of applications from cooling circuits, dosing pumps, white goods, CIP systems for food industry, agricultural machines, industrial wet vacuum cleaners, to gear oil used in metalworking and mining, IST AG's new thermal OOL mass flow meter can be easily integrated into new or existing industrial systems.


Continuous gas flow monitoring 

Flow sensor SFS Flow Module

The SFS Flow Module is a linearized mass flow module for gases that can be implemented in the application ready for use. This compact module is primarily used in gas supply, gas dosing systems, analysers and manifolds. But the SFS Flow Module is also applied in process control, e.g. in modified atmosphere conditions in the range of low flow rates. Thus, the module is suitable for integration in medical devices. In environmental technology, the SFS Flow Module can be implemented in measuring devices for gas analysis and for continuous emission monitoring.


Our OOL Bubble detector detects bubbles of various liquids, incl. water, oil or coolants Its reliable switch indicates bubbles from ca. 1mm diameter; suitable for various liquids, including aggressive liquids. It is independent of flowrate changes and suffers minimal pressure loss.

Flow modules are used in:

Product video OOL Massflow Meter
OOL mass flow meter

Learn more about the OOL flow module for liquids and how useful monitoring mass flow & temperature can be.

Oil leakage detection

The ability to quickly detect leakage from a remotely controlled, autonomously operated machine, transformer, compressor or similar can avoid unplanned and costly repairs. An OOL module from IST AG enables such preventive maintenance, makes it feasible to plan, and protects against unscheduled downtime. 

Whitepaper oil leakage detection
















Mode of operation

SFS Gas Flow Module - mode of operation
Ready-to-use, linearized mass flow module for gases

Thanks to its bi-directional calorimetric measurement, the SFS Module provides fast, continuous gas flow monitoring with a response time ≤ 20 ms. It comes factory-linearized with a repeatability of 0.2 % and an accuracy of 2 %.

Webinars on usage of low sensors and flow modules

Thermal mass flow sensors

How the right sensor element can be help you turn a sensing idea into a product feature

Webinar: Thermal and flow control in medical devices

How to customize sensors for your medical application

Inline quality monitoring of Diesel Exhaust Fluids

Inline Quality Monitoring of Diesel Exhaust Fluid (AdBlue) by Using the 3ω-Method

Thin-film mass flow sensor for floor care application

How useful are our thin-film mass flow sensors for floor care applications? Listen to Tom Hall from IST AG and learn how our flow sensors could be useful for your floor cleaning device

Product launch webinar: OOL mass flow meter for liquid flow measurement

Learn more about applications the new flow sensor with a stainless-steel channel fits seamlessly into, as well as customization options available for special application & assembly requirements.

Quality Assurance
Quality assurance

As an ISO 9001:2015 (quality) and ISO 14001:2015 (environment) certified company, our processes are designed around our customer’s needs. Our highly trained and empowered employees as well as our quality management system form the foundation and essential framework for establishing standards, communicating them, and consistently integrating them into daily work.