In the sphere of terotechnology and sewage treatment plant operators the demand for universal, reliable as well as easy installation and removal of measuring and operational monitoring systems is a matter of course. Endurance and soilage sensitivity are as important as proven practical operation.

For many years vortex flow sensors manufactured by Höntzsch/Waiblingen have been successfully installed for measuring activated sludge air and biogas in sewage treatment plants. Recording and regulation of volume flow of activated sludge air with vortex flow sensors is assured most reliably. The accumulation of the amount consumed (in cubic metres) sanctions proof of economic efficiency.

By using the sensor designed as an insertion probe the pressure drop, which as for instance arises in orifice flow systems and influences the efficiency of the plant, is reduced to less Pa. The flow velocity of the supply air for an activated sludge basin lies in the range of 0.5 to 25 m/s, this being irrespective of the pipeline diameter. This broad spread is reliably covered by the vortex flow sensor.

Installation of the flow sensors is by welded connectionn piece with connecting flange. The use of a probe guide system means that the sensor is movable, thereby enabling the operation of practically all occurring flow cross sections with one single probe type.

But Höntzsch vortex flow sensors are not only used for recording and regulating activated sludge air but also for measuring the biogas arising. For this application the fact that the vortex principle of measurement registers the flow irrespective of density, pressure and temperature of the working medium, thereby delivering reliable results even under critical operating conditions, has proven to be a special advantage. The special design of the sensor head ensures that neither moist gas nor condensation laden gas have a negative effect on the measuring system: even in subatmospheric pressure, velocities from 0.5 m/s can be measured! Vortex flow sensors are of course also approved for use in potentially explosive areas!

Installation and maintenance are carried out in a similar way to the application of measuring activated sludge air. The installation of a globe cock, which is mounted between connecting branch and guide piece, is of a special advantage. It allows the probes to be drawn into the area of the probe guide piece, the globe cock to close and finally the probes can be withdrawn in a closed measuring section.

The evaluation of the flow velocity or volume flow respectively is undertaken by transducers or systems instruments. In the case of additional measuring points multi-channel systems with display and keypad enable the free configuration of the parameter.

The velocity calibration for the entire measuring range of the sensors takes place in a free-jet wind tunnel at the plant. The competent control and checking of this calibration equipment by independent authorities guarantees the quality of Höntzsch vortex flow sensors.