Electricity and Control June 2020

MEASUREMENT + INSTRUMENTATION : PRODUCTS + SERVICES

Capacitive level switch for fluid, pasty and powdery media Martens, part of the GHM Group of Companies, has introduced the MLC437 Capacitive Level Switches for use mainly for the registration of limit levels, full/empty signals in pipes and tanks in fluid, pasty and powdery media, and for the dry running protection of pumps.

the tank wall (or built-in adapter/sleeve) thereby form an electrical condenser. If the switch is in the air, a specific low initial capacity is measured. When the switch is immersed in the medium, the capacity change is based on a change in the effective permittivity in the area of the measuring tip. This value is determined by the geometry of the switch and the DK-value of the medium. The measurement procedure enables the monitoring of the product and the detection of any separating layer, such as water/oil. Influences due to foam formation and adhesions are minor to non-existent. The MLC437 capacitive level switch is easy to service and maintain. For more information contact Jan Grobler, at GHM Messtechnik South Africa. Tel: +27 (0)11 902 0158 email: info@ghm-sa.co.za

Jan Grobler, Managing Director of GHM Messtechnik SA comments: “The MLC437 capacitive level switch has an analogue output and a DK-value (Dielectric Constant), which will open the door for applications requiring the measurement of differences between oil and water levels – a crucial element in maintaining consistency in the manufacture of products such as chemicals, pharmaceuticals and cosmetics, including applications where hygiene is essential.” Designed to suit applications in hygienic areas and the chemical industry, those parts of the Martens MLC437 switch that come into contact with the media consist only of materials that conform to FDA requirements. Furthermore, with the aid of the microprocessor-controlled measurement, the user can adapt the parameter setting to the process environment using a PC. “A useful feature of the MLC437 is that during operation, if an error or condition occurs, the display backlight can be set to change colour. This is an easily identifiable alert for engineers to see the condition or to address the error,” Grobler adds. During measuring operations, the LCD display shows measured values. According to the parameterisation, the backlight operates permanently or the device enters the power safe mode. The Martens MLC437 Capacitive Level Switches register fluid, granular and pulverised media (not for use in areas subject to the risk of explosion). This charge transfer measurement procedure makes use of the storage capability of charges in the medium. The switch tip and

The MLC437 capacitive level switch is designed to operate in different media, including applications in hygienic areas and in the chemical industry.

Electricity + Control JUNE 2020

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