Level Measurement & Control

Level measurement in silos

January 2020 Level Measurement & Control

UWT has taken a traditional method of content measurement in silos and storage hoppers and remastered it to enable seamless integration with modern-day control systems and PLCs. The UWT NivoBob continuous level measurement system offers a high-tech version of a simple and reliable measurement principle, which works as follows:

The sensor weight drives down on a measuring rope/tape.

The rope/tape length is electronically measured by the rotation of the internal roller.

Material contact stops movement.

The motor changes the direction of rotation.

Sensor weight is driven back to the upper stop position.

The distance is measured, and signal outputs are activated (pulse/relays/4-20 mA/Modbus/Profibus).

Application example

The challenge: level measurement to be carried out in storage silos for gypsum powder. The finished product is conveyed pneumatically into the storage silo after production. The overall production planning is difficult if the fill level monitoring of the storage silos is missing. The operator previously had to climb onto the silo roof and carry out a manual level measurement with a rope and a weight. This yielded inaccurate results and caused stock losses due to poor management and control. The task was to automate the level measurement and to avoid manual interventions.

The solution: the UWT system Nivobob 3200 in the tape version fulfils these extreme requirements. The integrated tape cleaner prevents contamination of the band interior. The Nivobob 3200, thereby, provides a reliable measurement that can be trusted. Neither dusty nor clumpy conditions adversely affect the system. The electromechanical sensor NB3200 is developed for dusty applications and for high process temperatures and is the best solution in this gypsum storage application.

Note: when it comes to ignoring the cone after filling or the upside-down pyramid after draining the silo/bunker, and achieving reliable, accurate measurement results, experience play a role. The NivoBob must be mounted one third in from the radius of the silo to accurately cancel out the cone effect.


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