The level measurement of a container whether liquid, solid or powder in a tank, silo, hopper is achieved by the addition of weighing sensor (weighs).
This technique makes it possible to obtain a high accuracy reliably provided you follow any rules you find in this article.
Choosing weighing sensors
Different sensor technologies exist depending on the constraints of use: bending sensor, single or double shear, compression, traction.
Determining weighing sensors
- Compression, traction, shearing.
Number of sensors and support points.
Weighing range and sensor capacity.
- Operating and functional mode:
Easy assembly and maintenance.
Transmission of the signal.
- Environmental conditions:
Influence of rigid bonds
- Risk control:
ATEX explosion risk.
Number of sensors and support points
Mechanical environment and assembly kit
Each sensor is equipped with a mechanical environment that facilitates assembly and ensures the mechanical safety of the silo and sensor. The 300 and 400 series has jack screws for the safety of the set during assembly or maintenance operations. Our mechanical environments are calculated and tested to resist parasitic forces in the 3 planes (refer to the technical sheet of each environment).
Weighing accuracy is the measurement error for a load, not to be confused with the display rung (multiple of 1, 2, 5). Accuracy depends on several factors:
- Sensor errors < (0.01%).
- Calibration error (automatic calibration of the indicator 0.1% or with standard masses < 0.01% ).
- Mechanical error (mechanical stress of the ducts, bridge, cone supports …) of up to 1 t in practice.
- Combined Sensor Error: E-N x Sensor.
Display and signal transmission
The LOCAL display allows signal processing and conditioning as close as possible to the source. In addition, the display is very practical for maintenance and diagnosis.
– Generally it is equipped with an analog output (4-20mA) or digital (ETHERNET, PROFINET, PROFIBUS, MODBUS…).
Flexion or simple shearing
Weighing range 10 to 5,000 kg
Accuracy < (0.05%)
– Limited in maximum capacity
Double shear sensor
Weighing range 5 to 100 t
Easy implementation: effort is distributed and centered
Mechanical reliability (double supports)
– Accuracy ( < 0.1% )
Weighing range 15 to 500 t
Used for heavy loads > (100 t)
Load descents centered on a single axis, simplifying the design of the supports
– Very sensitive to misalignment of support
– No built-in sensor security.