Direct measurement of volume flows

http://www.intl-sensor.com Time:2010/10/27 15:13:07 Count : 3882 Times

Direct measurement of volume flows

Schmidt Technology now presents maintenance-free flow sensors also for high temperatures

Thermal flow sensors, A ceramic chamber head in aerodynamic design protects the sensor element, which is also made of high-temperature resistant ceramic substrate

SCHMIDT Technology: Thermal flow sensors are often used for measurement of volume or mass flows of gases. An innovative and universal solution by Schmidt Technology now allows measurements at temperatures up to 350 °C.

Flow velocity and volume flow can be measured according to the thermal anemometer principle. With this method, a sensor element is continuously heated to a temperature which is maintained, via a regulating circuit, at a constant value of about 40 °C above the medium temperature. Immersed in a medium to be measured, the sensor element cools down by the air or gas flow. The heat transition from the heating element to the medium is a measure of the medium's flow velocity.

The advantages of this method lie in the measurability of very low air flows from 0.2 Nm/s up to very high volume flows, such as exist in compressed air. Moreover, a thermal flow sensor is very robust, maintenance-free and quick-acting.

New materials resist high temperatures

At high temperatures, the use of thermal anemometers has been limited so far. By combining long experience in manufacturing flow sensors with latest technologies and materials, Schmidt Technology has now been able to present a new generation of sensors enabling measurement of the actually prevailing volume flow even at high temperatures.

SS 20.650 is the name of the new product which features special connecting elements and a sensor element made of high temperature resistant ceramic material. The chamber head, which is also made of high-temperature resistant ceramic material, protects the sensor element against mechanical strain or high pressures.

Mounting lengths at customer's option

With a pressure resistance of 16 bar, the flow sensor can now also be used for measurements at a maximum temperature of 350 °C. The mounting lengths range from 400 mm to 1000 mm; customer-specific lengths are also available to cope with any installation situation.

Upon request, the sensor can be supplied with high-precision calibration. For this purpose, Schmidt calibrates each sensor against reference measurement channels and records precision and reproducibility in an ISO calibration certificate.

No drift and no maintenance

The SS 20.650 sensor's ability to measure the operating volume flow without using auxiliary variables and calculations and its high dynamic measuring range from 0,2 Nm/s to 60 Nm/s extends the application range and ensures high long-term stability without risk of drift and without requiring maintenance. Furthermore, it is the perfect choice for measurements at spots difficult to access.

Being maintenance-free, quick-ackting and featuring pressure and high-temperature resistance, the universal SS 20.650 sensor enhances the advantages of its predecessors.