Low Pressure Drop Digital Flow Meters

Sensirion offers low-pressure drop digital flowmeters that are highly accurate and update the readings very fast. These meters are available in fully calibrated form along with built-in temperature compensation.

The SFM3000 sensor is a digital flow meter that Sensirion has designed for applications with high volumes of flow. The flow meter allows measuring with superb accuracy the flow rate of air, oxygen, or other non-aggressive gases. Sensirion has designed the flow channel in a special way so that introduction of the flow meter into a flow system results in a very low-pressure drop. These characteristics of the SFM3000 make it extremely suitable for use in applications that are very demanding, such as in respiratory and medical ventilation systems.

Operating the SFM3000 is very easy, as the flow meter operates off a 5 VDC supply voltage. It also features a 2-wire digital I2C interface for connecting with the controller. Sensirion has designed the flow meter such that it automatically linearizes and temperature compensates all measurement results internally.

A CMOSens sensor technology, patented by Sensirion, is the basis of the outstanding performance of the sensor. They have combined the sensor element, signal processing electronics, and digital calibration within a single microchip. A thermal sensor element measures the flow rate of the gas, and this also ensures that the signal processing is done at a high speed. The innovative measuring technique also makes it possible to make bidirectional measurements, while offering the best-in-class accuracy.

The CMOS technology is well-proven and is a perfectly suited method for high-quality mass production of the SFM3000 flow meter in a demanding and cost-sensitive market. Sensirion offers a variety of custom options for implementing the flow meter for high-volume OEM applications. They offer options like different body form factor, calibration for other gases, custom flow rates, and many more.

Applications of the SFM3000 low-pressure drop digital flow meter include laboratory use, environment monitoring, spectroscopy, fuel cell control, burner control, process automation, and medical use.

Sensirion has used a silicon sensor chip SF05 of the fifth generation in the design of the SFM3000 flow meter. It also has a sensor element to detect the flow of thermal mass. In addition to the two above, there is an amplifier, an analog to digital converter, read-only memory, digital circuitry for signal processing, and the digital I2C interface. Sensirion has achieved significant cost benefits and performance achievements with the seamless integration of the circuitry for acquiring the signal and processing it on a single silicon die.

Users can solder the SFM3000 sensor using standard selective soldering systems. However, they must not use reflow soldering as it may damage the sensor. During soldering, the user must protect the sensor ports from solder splash and flux. As the characteristics of machines for selective soldering may vary, the user must test the soldering arrangement before production use.

For soldering, Sensirion provides the mask drawing of the sensor for a reliable PCB attachment. For a sturdy integration of the sensor, the user must consider using the screw holes of the SFM3000. The fittings of the sensor correspond to the international standard ISO5356-1:2004.