Flow measurement easily handled
To be able to measure air and gas flows precisely and with repeatability a number of ‘correct’ parameters are required. For many flow sensors orientation relative to flow direction is essential for quality of results. The choice of the right sensor is also dependent on the gas to be measured. Dust and aggressive gases will also impact on the quality of results and also causes increased maintenance and replacement, with evident additional costs. In areas with potential for explosion hazard, as found in powder handling and oil/gas plants for example, sensors with appropriate approval are required, and limits the options of sensor supplier.
This flow sensor makes selection easier
The thermal SCHMIDT® Flow Sensor SS 20.500 offers an ideal solution for energy efficiency and complicated applications to include drying processes, exhaust discharge, glovebox and fume cupboard flows, volume flow control and many more. In addition to flow velocity the sensor also measures the process temperature and both of these parameters are available as independent outputs.
This combined measurement capability reduces the number of tapping points, easing installation and also offers an obvious cost benefit. Extreme flow angles of 360° axial and ±45° from vertical simplify positioning in the gas flow. A wide measuring range of 0.06 up to 50 m/s and traceable calibration via a high precision adjustment ensures accuracy and reliability of measurement.
Dust and aggressive gases? No problem!
The patented dumbbell head makes measurement possible in dust laden applications without influencing the measured value. If required, a mechanical cleaning is easily carried out by the user. Optionally and if required the sensor is available ATEX Zone 2 certified for use in hazardous areas and with special protective coating options for resistance to aggressive mediums, e.g. trace acids.
Accuracy in black and white
Also as an option the sensor is available with high precision adjustment. This option includes the supply of a factory calibration certificate with recorded accuracy and repeatability. This calibration is carried out in-house at Schmidt Technology with traceability to National Standards. A recalibration service is also offered.
How does it work?
The flow sensor in the stainless steel sleeve between both ”dumbbell disks“ is heated up to 40 K over medium temperature which is measured by an integrated temperature sensor. The required power for maintaining the over temperature is an indicator for the flow velocity, which is output as “norm velocity”. Thus an additional measurement of pressure or medium temperature is not required. Both “dumbbell disks” have the function of flow rectifiers, therefore even relatively irregular flows can be measured.
Applicable in inflammable environments
The optional ATEX version SS 20.500 Ex has been designed for applications in potentially explosive atmospheres – gases and dusts – of zone 2. For this purpose special protective functions are integrated amongst others, e.g. the protective sleeve for the plug-in connector of connecting cable and the earthing terminal on the housing. For difficult installation situations the version “remote“ is recommended. In this case the additional earthing on the sensor tube has to be considered for the ATEX version.
Medium :Air / nitrogen or other gases on request
Measuring range : 0 ... 50 m/s
Output :0 … 10 V / 4 ... 20 mA
Operating temperature : -40 ... +85°C
Accuracy：±(3% of measured value + [0.4% of end of measuring range; min. 0.02 m/s])
Operating pressure : Compact sensor 10 bar (overpressure) / Remote sensor atmospheric (700 hPa … 1,300 hPa)
Type / class of protection：IP67 (sensor head) / IP65 (housing) / III (SELV) or PELV