Maintenance, Test & Measurement, Calibration


Hygienic limit switches for processes

February 2020 Maintenance, Test & Measurement, Calibration

Process and storage vessels incorporate limit switches to prevent overfilling of a tank or vessel (full indicator) or dry running of a pump (empty indicator). Anderson-Negele’s NCS series are ideally suited for the reliable measurement of limits in media with low water content, such as certain alcohols and cosmetics, providing universal application in bottling and pharmaceutical applications.

Capacitive working principle

Anderson-Negele level switches operate on the basis of the capacitive working principle. The measuring electrode, the medium and the conductive wall of the tank form an electrical capacitor influenced by three main factors: distance; area of the electrode surfaces; and type of medium between the electrodes.

The measuring electrode and the tank wall serve as the capacitor plates while the medium acts as the dielectric fluid. Due to the higher dielectric constant of the medium relative to air, the capacity increases when the electrode is immersed in the medium. Exposing the electrode has the opposite effect. The change in capacity is analysed by the level switch and converted to a corresponding switching command. The sensor outputs a 24 V DC signal (active output). The minimum and maximum (full/empty) switching functions can be swapped by reversing the polarity of the power supply. The capacitive working principle requires that the sensor tip, which is made of PEEK, be completely immersed in the medium. The advantage is that the sensor does not respond to foam or adherences and a signal is emitted only when the medium reaches the level. Capacitive measurement is most reliable when the dielectric conductivity and temperature of the medium are constant. Changes in the outer conditions are generally non-critical in media with high dielectric constant values.


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Suspended solids sensor
April 2020, Morton Controls , Sensors & Transducers
Morton Controls, in partnership with Quadbeam, has introduced the Stormwater and Wastewater sensor, the SWW, the newest suspended solids sensor/turbidity meter available. Quadbeam has created an incredibly ...

Read more...
Closing the gap
April 2020 , Maintenance, Test & Measurement, Calibration
A new closed side setting (CSS) measurement device – the C-Gap – is now available to the South African market through Control Systems Rustenburg and Steelpoort. The C-Gap offers accuracy, safety and reliability ...

Read more...
Condition monitoring systems from ifm
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, ifm - South Africa , Maintenance, Test & Measurement, Calibration
The ifm product range comprises systems for monitoring vibration, oil quality, compressed air and water consumption.

Read more...
Data and digital technologies power new trends in asset management
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020 , Maintenance, Test & Measurement, Calibration
With technological and product changes across the enterprise fundamentally changing EAM, users in today’s industrial organisations now have new tools to better assess how they monitor, maintain, and manage their assets.

Read more...
Beyond preventive maintenance
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, Parker Hannifin Sales Company South , Maintenance, Test & Measurement, Calibration
Condition monitoring and predictive maintenance to improve efficiency and reduce costs.

Read more...
Asset Performance Management 4.0 and beyond with risk-based maintenance
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, IS³ - Industry Software, Solutions & Support , Maintenance, Test & Measurement, Calibration
Implementing Asset Performance Management (APM) 4.0 enables the transition to full risk-based maintenance for improved asset performance, increased asset reliability, reduced risk, and ultimately, maximum return on asset investments.

Read more...
ABB launches Ability Condition Monitoring for measurement devices
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, ABB South Africa , Maintenance, Test & Measurement, Calibration
The ABB Ability Condition Monitoring for measurement devices is an innovative, digital solution that will keep continuous gas analysers under control to ensure clean air operations. The ground-breaking, ...

Read more...
A maintenance tool for analysis and process systems
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, SICK Automation Southern Africa , Maintenance, Test & Measurement, Calibration
Digital Maintenance Manager: The ideal entry point to process automation 4.0.

Read more...
Condition monitoring specialists boost machine reliability
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, Wearcheck Africa , Maintenance, Test & Measurement, Calibration
WearCheck specialises in boosting the availability and reliability of components, thereby helping its customers to operate more efficiently and save money on maintenance in industries such as mining, earthmoving, transport, shipping, industrial, aircraft and power generation.

Read more...
BMG filtration solutions offer reliable contamination control
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2020, Bearing Man Group t/a BMG , Maintenance, Test & Measurement, Calibration
BMG’s Fluid Technology division is committed to improving operational efficiencies for customers in all industries by providing essential filtration, separation and purification technologies. “With broad ...

Read more...