SelectIion Chart for Point Level Measurement Technologies ~ Learning Instrumentation And Control Engineering Learning Instrumentation And Control Engineering

SelectIion Chart for Point Level Measurement Technologies

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Point level measurement is commonly done using the following technologies
(a) Capacitance sensors
(b) Nuclear sensors
(c) Vibrating fork sensors and
(d) Float switches
The above technologies are often best suited to certain process conditions or a combination of process conditions. To apply these technologies, some questions commonly asked include:
  1. Which level measurement technology best suits density changes in the process?

  2. Which technology will suffice for a changing dielectric strength of process fluid?

  3. Which technology can be best used where you have solids, dust, foam, slurries, emulsion, internal obstructions, vapors, viscous/sticky product?

  4. Which technology is best suited for high process temperature limits, high vessel pressure limits, low process temperature limits, low vessel pressure limits?

  5. Which level measurement technology can best resist noise (EMI, motors), product coating etc?

  6. Which technology is best suited a process where there is aeration, agitation, ambient temperature changes, or corrosion?

The above questions are
answered by the selection chart below which details which level measurement technology is best suited for all sorts of process conditions.
Key to Understanding Table:
 G = This process condition has little or not effect on the performance of the  level measurement  technology.
M =  This technology can handle this condition, but performance could be affected or if used, special
         installation is required.
P  = This technology does not handle this condition well.

Process Conditions Capacitance Nuclear Float Switch Vibrating Fork
Aeration G M G G
Agitation M G G G
Ambient temperature changes G G G G
Corrosion G G M M
Density changes G M M G
Dielectric changes P G G G
Dust G G G G
Emulsion G G G G
Foam M G G M
High process temperature limits G G G G
High vessel pressure limits G G G G
Internal obstructions M M G G
Low process temperature limits G G G G
Low vessel pressure limits G G G G
Noise (EMI, Motors) G G G M
Product coating P M M M
Solids M G P P
Slurries G G M M
Viscous/sticky products M G M M
Vapors M M G G