Gas flow sensors

For medical and industrial applications

High performance gas flow measurement

With a long history of designing mass flow solutions for medical technology and industrial automation, Sensirion is an ideal partner for developing new products. Sensirion offers gas flow sensors for diverse applications, characterized by:

Excellent repeatability
Fast response time
High sensitivity at low flows
Wide dynamic range
Reliability and robustness
Bidirectionality

For more information, please visit: www.sensirion.com/gasflow

Unique measurement principle

Sensirion's gas flow sensors ensure fast, accurate, and economical measurement of gas flow over a wide dynamic range. At the heart of every Sensirion flow sensor is a MEMS-based calorimetric microsensor that measures gas flow using the thermal measurement principle. The sensor element is integrated with signal conditioning electronics on a single chip. This unique technological approach, powered by innovative CMOSens® Technology, results in excellent performance and robustness at a very attractive cost. This is why today's leading manufacturers rely on Sensirion's highly sensitive flow meters.

Illustration of measurement principle:

A diagram shows a cross-section of the sensor. A 'Heater' is positioned above a channel. 'Temperature sensors' are located on either side of the heater. 'Gas flow' is indicated moving from left to right. The 'Silicon' substrate is shown below. A scale bar indicates '1 mm'. The diagram visually represents how heat is distributed and measured as gas flows over the sensor.

Evaluation kits for fast and easy testing

The SEK-Flow Sensing evaluation kits are test sets for Sensirion's gas flow sensors. Precise test measurements can be made quickly and inexpensively with these ready-to-use kits. The evaluation kit consists of an adapter cable that allows direct connection of the sensor to your computer. In some cases, a Sensirion sensor bridge multiplexer completes the kit. The viewer software can be downloaded from the Sensirion website. The software allows measurements at various resolutions and displays mass flow in standard liters per minute (slm). Data can be logged and exported.

Products

Sensirion mass flow meters offer flow sensors that are temperature-compensated and fully calibrated. No further calibration or drift compensation is needed. The SFMxxxx sensors are designed for high-volume production using industry-proven technology with a track record of more than 20 years.

Flow sensors for limited overpressure and dry gases

All flow sensors designed for ambient pressure and gases are built for a lifetime of many years and provide high reliability, using carefully chosen materials and drift-free technology. The SFM3505 family features O-ring fittings for a compact form factor and can operate with up to 650 mbar overpressure. Its new flow body design ensures unmatched accuracy, noise, and pressure drop over the large flow range of +/-300 slm. The SFM3505-70-CO2 offers a CO2 flow sensor for up to 70 slm.

The SFM3003 series has medical cones fittings (compatible with ISO5356), is calibrated for Air, O2, and mixtures thereof, and operates with up to 0.3 bar overpressure. There are three different versions available with different flow rates and pressure drops: SFM3003-300-CL, SFM3003-300-CE, and SFM3013-300-CL. A version with Heliox calibration also exists: SFM3013-300-CLM.

Flow sensors for ambient pressure and humid gases

Sensirion's flow sensors designed for use with humid and condensing gases can measure up to 250 slm. They feature an integrated heater to prevent condensation on the chip, ensuring optimal performance in humid conditions. All sensors have a connector design allowing for clip-on cables and easy connection/disconnection. In certain applications (e.g., medical), contamination can occur. The SFM3x00-AW sensors can be washed or autoclaved, while the SFM3x0x-D sensors are single-use. They are available in two sizes: the SFM3304-D, with 22 mm medical cones and a dead volume below 10 ml, and the SFM3400-AW/D, with 15 mm medical cones and a dead volume below 1 ml. Single-use sensors are also available in customized individual packaging.

Flow sensors for high operating pressure

The SFM4xxx, SFM5xxx, and SFM6xxx series are ideal solutions for applications where the pressure inside the sensor can reach several bars for extended periods. These particularly robust sensors are designed to withstand harsher conditions and are calibrated for a large variety of gases. The SFM4300 can measure positive flows (up to 20 and 50 slm) of Air, O2, CO2, N2O, and mixtures thereof.

The SFM6000 series offers even smaller flow ranges, RS485 communication, and exchangeable fittings. The SFM5xxx series, made with metal bodies, offers high-accuracy flow measurements for various flow ranges at pressures up to 10 bar. The SFM5xxx and SFM6xxx are also available as mass flow controllers.

Special feature	Low pressure and dry gases		Low pressure and humid gases		High operating pressure, dry gases
Special feature	SFM3003-300-CL	SFM3505-300-X	SFM3304-250-D	SFM3400-33-D	SFM4300-20-O/P/B	SFM6000*	SFM5400/5500*
Flow range	-30 to 300 slm	-150 to 300 slm	-250 to 250 slm	-33 to 33 slm	0 to 20 slm	0 to 5, 20 or 50 slm	various flow ranges from 0 to 50 sccm to 0 to 100 slm
Accuracy (typical)	2% m.v. up to 200 slm	1% m.v. over full range	3% m.v. up to 100 slm	3% m.v. over full range	2% m.v. over full range (Air, O2)	2% m.v. over full range (Air, O2)	0.8% m.v. over full range (air, He, O2)
Noise (N)/repeatability (R)	N: 1% m.v. up to 200 slm	N: 1% m.v. over full range	N: 0.5% m.v. up to 25 slm	N: 0.5% m.v. over full range	R: 0.21% m.v. over full range	R: 0.2% m.v. over full range	R: 0.1% m.v. over full range
Pressure drop	< 5 mbar at 200 slm	< 7.5 mbar at 200 slm	< 19 mbar at 200 slm	< 1 mbar at 25 slm	< 25 mbar at 20 slm	< 150 mbar at 50 slm	< 100 mbar at full flow
Fluidic interface	Medical cones 22mm, O-rings	O-ring, 14mm inlet diameter	Medical cones 22 mm	Medical cones 15mm	O-ring 8 mm, push-in, Down-mount	Push-in, Downmount	Legris OD 6mm with exchangeable G 1/4" thread
Interface	I²C	I²C	I²C	I²C	I²C	RS485 and I²C	RS485, Modbus, Analog, DeviceNet* (*only for SFM5400)
Sampling time	0.5 ms	0.25 ms	0.5 ms	0.5 ms	0.5 ms	1ms	1ms
Calibrated for	O2, Air and mixtures thereof	Air, O2	Air	Air	Air, O2, CO2, N2O and mixtures thereof	Air, O2, CO2, N2O, Ar	Air/N2, O2, He, H2, CH4, N2O, Ar, CO2
Power supply	2.7-5.5 V	3.2-3.4 V	3.15-3.45 V	4.75-5.25 V	3.0-5.5 V	22.8-25.2 V	15-24 V
Allowed overpressure	0.2 bar	0.65 bar	0.1 bar	0.1 bar	10 bar	10 bar	10 bar
Variants/other versions	SFM3003-300-CL: -30 to 300 slm SFM3003-300-CE: -150 to 300 slm SFM3003-300-CET: add'l gas temperature sensor SFM3013-300-CL: 1 bar overpressure SFM3013-300-CLM: Heliox calibration SFM3020: analog output	SFM3505-300: 2.3% typical SFM3505-300-X: 1% typical SFM3505-70-CO2: CO2 flow up to 70 slm	SFM3304-250-D: single-use SFM3300-250-AW: washable, autoclavable	SFM3400-33-D: single-use SFM3400-33-AW: washable, autoclavable	SFM4300-20-O/P/B: 20 slm range, O-ring/push-in/basemount fittings SFM4300-50-O/P/B: 50 slm range, only air and O2, O-ring/push-in/basemount fittings	SFM6000D-5 slm: 5 slm range SFM6000D-20 slm: 20 slm range SFM6000D-50 slm: 50 slm range	SFM5500-50sccm: 50 sccm range SFM5500-0.5slm: 0.5 slm range SFM5500-2slm: 2 slm range SFM5500-10slm: 10 slm range

* All versions are also available as mass flow controllers

What we offer

Expert first contact

Specialized and experienced sales force
Worldwide presence with a global distribution network

Fast and easy product evaluation

Comprehensive product portfolio
Easy-to-use evaluation kits for effortless measurement during sensor evaluation
Technical documents – data sheets, sample codes, and application notes

Design-in support

Assistance with integrating Sensirion's sensors into your application
Proven best practices to ensure that your production concept accommodates the requirements of our gas flow sensors

Lifetime support

Reliable and flexible production
Sustainable product innovation roadmap to meet your future needs

Customized solutions

Various flow rates
A variety of gases (multigas option)
Special form factor requirements

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