Challenge: Unreliable level readings and rising costs
At an industrial facility with storage silos for plastic granules, the operators faced a familiar issue:
The level readings had been displayed unreliably for years.

Five silos, each approximately 9 m (30 ft) high and 3.5 m (11.5 ft) in diameter, were filled alternately with different types of granules. However, the displayed values could no longer be trusted.

The result:
Material was ordered only when needed – without reliable planning.
With fluctuating plastic prices, this led to unnecessary costs and additional effort.
On site: A surprising discovery
Together with our technical service and product management team, we analyzed the situation directly on site.
Installed on the silos: five mechanical plumb bob level systems of type SLS 100 – a classic rope-operated level system and the predecessor of today’s NivoBob®.

One detail stood out immediately:
The sensors were manufactured on February 13, 1990.
More than three decades in continuous operation – under real process conditions.
The technical design of these sensors has proven itself over decades.

Reliable level measurement – clear analysis of measurement signals
A short technical inspection quickly revealed:
The UWT sensors were operating perfectly and provided accurate measurement signals.

Measurement principle:

•  A sensing weight is lowered into the silo via a steel cable 
• One pulse is generated per decimeter
• The pulses are externally converted into level values
  
  The cause of the incorrect level readings was not related to the sensor technology:
  The external evaluation system – not part of the UWT solution – misinterpreted the pulse signals. The UWT sensors continuously delivered correct and reliable measurement data.

Conclusion: Quality proven over decades
This application clearly demonstrates the performance of durable level measurement technology:

• more than 35 years of precise and stable level measurement
• robust, low-maintenance sensor technology for continuous operation
• clear separation between sensor and evaluation enables fast root cause analysis

Mechanical rope-operated systems such as the SLS 100 – now further developed into the NivoBob® – stand for exactly this:
Technology that delivers reliable performance over the long term – even under real process conditions.