Flow Measurement & Control

Magnetic-inductive flow meter for phosphate precipitation

June 2022 Flow Measurement & Control

Kobold was tasked to provide a solution for the problem of phosphate precipitation in wastewater treatment plants. By adding iron(III) chloride (FeCl3) into the aeration basin, the phosphates dissolved in excess wastewater are chemically mixed with sludge flocculants and transferred with sludge to the sludge treatment stage. This process reduces phosphate concentration in waterways and minimises the potential for abnormal algae growth and the detrimental effect on the aquatic ecosystem. Because an overdose of FeCl3 results in badly polluted water that is toxic to humans as well as the environment, a dependable method of process monitoring was sought.

The ideal was a continuous flow measurement of the dosing chemical with a direct data connection to the process control system, which would guarantee water treatment plant owners maximum safety so that possible errors were not discovered only after the event (during sample taking) when it´s too late.

The solution on offer from Kobold is the MIK magnetic-inductive flow meter, an optimal and economical solution for a safe dosage of FeCl3, and specifically developed for this very application. The unit has already proven itself successfully in service, specifically for electric conductivity liquids, acids and caustic solutions, drinking, cooling and wastewater, groundwater, raw water, aggressive or salty solutions, but is unsuitable for oil since it lacks conductivity.

The MIK is housed in polyvinylidene fluoride (PVDF) and the electrodes in contact with the medium are made of tantalum. Both materials have proven to be totally chemically resistant. With the directly mounted transmitter with stainless steel housing, this device forms a very compact yet robust unit ideal for fitting inside cramped control cabinets. It allows detection of very small dosage amounts from 10 ml/min.

The device operates according to the principle of electromagnetic measurement – Faraday's Law of magnetic induction – where a voltage is induced in a conductor moving through a magnetic field. The electrically conductive measuring agent acts as the moved conductor. The voltage induced in the measuring agent is proportional to the flow velocity and is therefore a value for the volumetric flow. The flow rate is calculated on the cross-sectional area of the pipe. The measurement is dependent on the process liquid and its material properties, such as density, viscosity and temperature. The device may be equipped with a switch, frequency or analog output.

With an analog 4-20 mA signal (or optional pulse output) the MIK continuously communicates the measured values to the user’s process control system, allowing for immediate response to the latest process conditions. This results in increased efficiencies and cost savings in the amount of FeCl3 required to achieve phosphate removal, as well as the vitally important environmental protection component.

Areas of application are flow monitoring, flow measuring, dosing and counting for machine building, the chemical industry, paper industry, automobile industry, cement industry and laboratories. Finally, Kobold asserts that automation guarantees high standards of plant safety even at unmanned plants.

For more information contact Instrotech, https://bit.ly/3hKepPm


Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Pressure sensors for perfect coffee
Instrotech Pressure Measurement & Control
Rex-Royal has sourced pressure transducers from Keller’s 21C series for its S300 model range of bean-to-cup coffee machines.

Pulse totaliser counter
Instrotech Flow Measurement & Control
The electronic unit shows flow rate, resettable daily and total counter (mass units can also be set), and all customised program settings remain saved, even after a battery exchange.

Permanently precise flow measurement
Morton Controls Flow Measurement & Control
Proven and tested in practice, the small size of the FMQ’s measuring body and electronics enable simple, vibration-insensitive integration into almost all applications.

Ultrasonic sensors enable automatic stacking turf harvester
Instrotech Sensors & Transducers
The AutoStack, and now the AutoStack II, use an automated Ultra Steer system to guide the harvester with precision while the operator watches over all aspects of the harvesting process.

Mass flow controllers and meters
Electrocomp Flow Measurement & Control
Unlike most other devices on the market, these devices do not suffer from drift and do not require in-service recalibration.

Compact infrared camera for the metal industry
Instrotech Temperature Measurement
The camera’s wide temperature measurement range of 450-1800°C satisfies practically all demands in the fields of metal production and processing.

Inline process viscometer for polymer and oil monitoring
SECO Process Instrumentation Flow Measurement & Control
This hermetically sealed unit is assembled entirely from 316L stainless steel and includes built-in fluid temperature measurement.

Wall-mount ultrasonic flow meters
Royce Water Systems Flow Measurement & Control
High measurement accuracy and minimal interference due to its advanced error correction technology are among the flow meter’s benefits.

Wire-actuated encoder for crane arms and lifting platforms
Instrotech Sensors & Transducers
Siko has solved the challenges presented by such applications with the SG 30 and its very compact, yet robust, design.

Flow meters and switches for very slow flows
Instrotech Flow Measurement & Control
Kobold’s KSV meters are shock resistant, small, lightweight and simple to install for measuring liquid or air flow with full-scale accuracy within +/-6%.