Sensors for Mass Flow Measurement

Mass Flow Sensors

IST thin-film mass flow sensors provide solutions for a variety of flow applications in both liquid and gas. Our thermal mass flow sensors have an operating range of -40 to 160°C (+450°C – customer-specific), and can measure velocity flow rates from 0 to 100m/s. Most thermal mass flow modules and measuring systems in the marketplace are sufficient for many general purpose applications where component price and size are less significant, but they are not well-suited for price-sensitive and space limited flow control solutions. In such cases, IST thermal mass flow sensor elements offer a suitable solution with considerable advantages:  

  • High sensitivity
  • Easy to implement, simple electronics
  • Excellent long-term stability
  • Development of customized sensor layouts for both high and low volume applications

Flow Sensor Types

The thin-film and membrane technologies incorporate highly accurate temperature sensors and heaters as core elements of the sensors. In addition to measuring flow rates, our liquid sensors can detect the presence of a liquid, biofilm, or bubbles, as well as indicate liquid level.

  • Flow Sens (FS2, FS7, FS7.4W )
  • Microflow Sens (MSF02, MFS05, MFS06, MFS03)
  • Flow sensors for liquids (OOL – Out of Liquid)

FS Flow Sensors

Key features:

  • Flow range: 0 m/s to 100 m/s
  • Temperature range: -20 °C to 150 °C resp. +400 °C for applications in high temperature areas
  • Voltage range (nominal): 2 V to 5 V (dependent on flow velocity)
  • Electronics: For FS7 and FS7.4W: FS Flow Module (for the evaluation of the sensors)
  • Accuracy: < 3 % of the measured value (dependent on the electronics and calibration)
  • Temperature sensitivity: < 0.1%/K (dependent on the electronics)

Further features:

  • Easy calibration
  • Excellent long-term stability
  • Easy signal evaluation
  • Stable platinum technology
  • Very good reproducibility

    Customer-specific adaption possible

MFS Flow Sensors

Key features:

  • Flow range:
    • Full bridge mode: 0 m/s to 1.5 m/s resp. 0 ml/min to 100 ml/min
    • CTA-mode: 0 m/s to 150 m/s resp. 0 l/min to 10 l/min
  • Temperature range: -40°C to +80 °C
  • Voltage range (nominal): 2 V to 6 V (full bridge mode)
  • Electronics:
    • MicroFlowSens Amplifier Module (demonstration and evaluation)
    • MicroFlowSens EvaKit (easy evaluation)
    • Mass flow meter MFM.EVAL.01.DI2C (for very low differential pressure applications)
  • Accuracy: < 2 % of the measured value (dependent on the electronics and calibration)
  • Temperature sensitivity: < 0.1 %/K (dependent on the electronics)

Further features:

  • Very fast response time
  • Excellent for very low flow rates
  • Detection of flow direction
  • Low power consumption

    Customer-specific adaption possible

Flow Sensors for Liquids

Key features:

  • Flow range: 0 ml/min to 3000 ml/min (4 m/s)
  • Temperature range: -50 °C to +180 °C
  • Voltage range (nominal): 4 V to 10 V
  • Electronics: Out of Liquid Demo Module (demonstration of flow applications in aggressive liquids)
  • Accuracy: < 3 % of the measured value (dependent on the electronics and calibration)
  • Temperature sensitivity: < 0.2 %/K (dependent on the electronics)

Further features:

  • Suitable for aggressive liquids
  • High chemical resistance (construction with stainless steel probe)
  • No direct contact between heater/temperature resistor and liquid
  • Simple flow switches or exact mass flow meters possible

    Customer-specific adaption possible

Development channels guarantee the best possible adaptation of our sensors to the requirements of your application, whether in terms of dynamic range, response time, directional detection or ambient conditions.

Measurement Principle
Utilizing heat transfer principles, thermal mass flow sensors are able to determine the flow velocity of a fluid. When fluid passes across the sensor, heat is carried to the medium. This relationship is dependent upon the flow rate – when flow increases, so does the amount of heat that is transferred. Knowing the temperature of the medium makes it possible to determine the flow rate from the amount of voltage compensation needed to maintain a constant temperature differential.


IST’s New Technology for Ultra Low Gas-Flow Applications
Using the same thin-film construction philosophy as IST’s FS series flow sensors, the MFS02 employs a special glass substrate with an ultra thin polymer membrane to achieve extreme sensitivity. A high performance material, the polymer is characterized by outstanding thermal, mechanical and chemical behaviors. Reduced thermal conductivity of the polymer membrane leads to better thermal contrast and thus better sensitivity. Additionally, the sensor’s glass substrate allows for a much higher operating temperature, making the measurement of larger flow rates possible.

IST’s development of the micro flow sensor allows customers to specify dimensions and resistor layouts to fit their own applications. The MFS02 features a rugged design that is well-suited for soldering, conductive gluing, or wire bonding. The sensor element can be mounted as an assembly on an electronic PCB or other carrier, and is ideal for mounting in a bypass flow assembly for differential pressure applications. An EVA Kit is available through IST for performance evaluation of the MFS02 micro flow sensor.


IST flow sensors are used in a wide variety of industries, including:

  • Building Automation
    IST’s thermal mass flow sensors are used by the HVAC industry as an indicator of duct airflow, an important component in controlling building air quality and comfort.
  • Appliances
    IST’s flow sensors, with the ability to measure pressure differential and flow direction, are more than capable of meeting the needs of products in the appliance industry. Applications include  vacuum flow detector, smoke detectors, and washing machine flow.
  • Medical
    Flow sensors are widely used in the medical industry, controlling medical devices where a gas or fluid is being supplied to a patient, or in cases of patient monitoring. Applications include spirometers, dosing monitors, oxygen meters, vacuum meters, liquid medicine dosing.
  • Test & Measurement
    Our sensors can be directly integrated into instruments used in the test and measure industry, where highly accurate and stable sensors are crucial. Applications include compressed air meters, clean room observation, flow handheld devices, and weather stations.
  • Process Control
    IST's mass flow sensors meet the needs of this industry for measurement and control, which determine the effectiveness of products. Applications include industrial vacuum cleaners, gas flow control, and liquid flow control.
  • Automotive
    IST’s thermal mass flow sensors are capable of monitoring vital fuel and engine systems, a critical need in the automotive industry, where ever increasing innovation has created a need for accurate and robust measurement methods.  

IST USA Division offers a high degree of flexibility in sourcing and supporting our products. We offer in-house stock and on-site engineering support, which is available during our regular business hours for design, application, and after sales support.

Our Sensor Offerings Include:
Temperature | Humidity | Flow | Conductivity | BioSensors | Thin-Film

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