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:

Measure bearing vibration and temperature
June 2020, Comtest , Maintenance, Test & Measurement, Calibration
Vibration in rotating machinery is merely the back and forth movement, or oscillation, of a machine and components, such as drive motors, driven devices (pumps, compressors, etc.), and the bearings, shafts, ...

Read more...
Bently Nevada’s condition monitoring and protection system
June 2020 , Maintenance, Test & Measurement, Calibration
Why Orbit 60? Why Now? Bently Nevada prides itself on a history of machine protection and condition monitoring solutions. With over 60 years of innovation, over 100 000 rack monitoring systems, and ...

Read more...
C-Gap replaces current methods of CSS measurement
June 2020 , Maintenance, Test & Measurement, Calibration
Developed by Mintap, based in Perth, Western Australia, the Closed Side Setting (CSS) measurement device – the C-Gap – is now available through South African-based Control Systems Rustenburg. C-Gap offers ...

Read more...
Wireless machine monitoring
June 2020, SKF South Africa , Maintenance, Test & Measurement, Calibration
SKF has teamed up with connectivity expert LumenRadio to create a new wireless monitoring system, measuring vibration and temperature. The SKF Enlight Collect IMx-1 System combines SKF’s knowledge in ...

Read more...
Ratchet P-Clamp from HellermannTyton
June 2020 , Maintenance, Test & Measurement, Calibration
When a heavy-duty equipment manufacturer asked HellermannTyton to devise the most effective way to attach and remove cables for additional equipment, nobody imagined that a well-trodden path would lead ...

Read more...
Detect plant maintenance requirements
May 2020, ifm - South Africa , Maintenance, Test & Measurement, Calibration
The new smart ifm position sensors provide signals to alert operators before problems become critical. High resolution allows the sensors to detect even small changes in the switching area. In addition ...

Read more...
BMG’s products for welding fume extraction
May 2020, Bearing Man Group t/a BMG , Maintenance, Test & Measurement, Calibration
BMG’s Tools & Equipment division has introduced a range of specialist products, systems and services to assist industry to create a healthy and safe work environment, by reducing the risks associated ...

Read more...
Pressure-relief safety helmets
April 2020, RS Components SA , Maintenance, Test & Measurement, Calibration
RS Components has added the 3M SecureFit X5000 and X5500 Series safety helmets to its health and safety product portfolio. SecureFit helmets incorporate 3M’s patented pressure diffusion technology, which ...

Read more...
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, Control Systems Rustenburg , 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...