Proximal Flow Sensors
The SFM3300 and SFM3400 mass flow meters are sensors for proximal flow measurement in respiratory applications. Proximal flow sensors are widely used in respiratory devices for intubated patients and non-invasive ventilation patients in hospitals, home care situations and emergency rooms. With applications ranging from neonatal to adult care, the associated requirements for proximal flow sensors are both diverse and challenging.

The SFM3400 flow sensor is a proximal flow sensor for neonatal and pediatric applications in respiratory devices such as ventilation or anesthesia. The sensor is available as a single-use version (SFM3400-D) and a reusable version (SFM3400-AW).
- For neonatal and pediatric applications
- Flow range ± 33 slm (bidirectional)
- Dead space < 1 ml

The SFM3300 mass flow meter is a sensor for proximal flow measurement in respiratory applications such as ventilation or anesthesia. There are two versions available: the SFM3300-AW is autoclavable and washable and the SFM3300-D is single-use.
- For adult applications
- Flow range ± 250 slm (bidirectional)
- Dead space < 10 ml
Features
- Fully calibrated
- Very fast update time (0.5 ms)
- Best-in-class accuracy
- Robust and shock resistant
- Designed for proximal flow measurements (medical applications)
- Medical cones for pneumatic connection to standard breathing circuits
- Mechanical interface for easy and reliable electrical reconnection
Applications
- Proximal flow measurements
- Respiratory applications
- Ventilation
- Anesthesia
- Metabolic measurement
Single-use versions
- Disposable solution
- Optimized for low cost
Reusable version
- Autoclavable/ washable solution
- Extremely robust housing
- Extended EEPROM store usage data

The use and spread of ventilators will continue to grow strongly in the future due to the increasing number of lung diseases. Modern ventilators place ever-growing demands on sensors in order to place the focus on the patients and their therapy. The CMOSens® Technology has established a new generation of flow sensors that have proven their reliability millions of times in the field of CPAP devices and automotive applications with the advantages for ventilators being evident. This technological advantage will enable manufacturers to realize the next quantum leaps in ventilation.

In the past, the decision to opt for a particular flow sensing technology in respirators and ventilation devices was a painstaking and complex process. More recently, however, we have seen the emergence of flow sensor solutions that provide a fully calibrated and temperature-compensated output signal. Proximal flow sensors also have particularly high requirements with regard to hygienic sterilization due to the patient's contact with air, which can potentially be infected with pathogens.
There are already a number of sensor solutions on the market that can be sterilized with autoclaving or other methods. All of these sensors use one of two different measurement principles: the hot-wire anemometry principle, or differential pressure measurement via an orifice or a variable orifice to increase sensitivity at low flow ranges.