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BULK SOLIDS LABORATORY

Testing of physical properties of powder

  • Design of the silo geometry
  • Silo calculations according to EN 1991-4 or DIN 1055-6
  • Comparison of the flowability of powder
  • Iindustrial product design and optimizing
  • Quality conformance test and product certification
  • Process control to prevent operating trouble and/or damages
  • Avoid problems at product change
  • Solving problems of existing silos
  • Ensuring mass flow in a silo
  • Optimization of flow aids and/or processes
  • Calculation of the minimum outlet opening to avoid bridging
  • Research & development
  • etc.

 

silo calculations of bulk solids
mass flow or funnel flow silo

BULK MATERIAL TEST

To avoid problems during the storage and discharge of cohesive bulk materials, silos should always be designed for mass flow. In the case of mass flow silos, the whole bulk material is in motion during discharge. Problems, as they may arise from funnel flow, can be avoided in this way.
In the case of funnel flow, only parts of the bulk material are in motion. This may lead to

  • different residence times of the material in the silo, up to dead zones
  • segregation
  • ratholing
  • fluidization or shooting of the material
  • unsteady flow
  • time consolidation

Three physical quantities must be measured for a silo calculation:

  • yield locus
  • bulk density
  • wall friction

These values are not constants but functions and are measured at different consolidation pressures depending on the pressure level in your applications.

MEASUREMENT SERVICE

ASTM D6682-01
D6682-01

Take advantage of our longtime experience in bulk solids analysis. Measurements such yield locus, wall friction, bulk density, time consolidation as well as bulk material moisture are carried out using certified measuring instruments in in our lab. This will give you all parameters necessary for a silo calculation. Structured process procedures ensure a high quality standard and economic workflows.

  • YIELD LOCI

    (YL)
    angle of internal friction φi, effective angle of friction φe, cohesion, principal stresses σ1, σ2, unconfined compressive strength σc, flowability factor, time consolidation, ...

  • WALL FRICTION

    (WF)
    Static and kinetic wall friction, adhesion, approximation of wall friction, wall friction angle φw, φx, wall friction coefficient μw, ...

  • BULK SOLID DENSITY

    (DE)
    bulk density ρb0, compression density ρb1), density function ƒ(ρb1), ...

  • BULK SOLID MOISTURE

    (MO)
    %M (percent moisture), %S (percent solid), ...
Silo calculations according to EN 1991-4 or DIN 1055-6 yield loci bulk solid moisture density measurement wall friction
bulk solids measurement data silo geometry bulk material parameter silo hopper filling state mass flow or funnel flow silo hopper discharge state bridging stresses vertical section time consolidation effective angle of friction density funtion fow funticon

EVALUATION

Automated and customizable reports simplify to use the results. Automatic analysis of the measurements and further calculations, such flow function, stress conditions in the silo, limiting criterion for mass flow or funnel flow, bridging (critical outlet diameter), load on the discharge device are online available after the measurements. It is even possible to automatically calculate and compare different silo shapes and dimensions automatically.

  • Statistic analysis

    of yield loci, wall friction, density and moisture measurements
    .: standard deviation SD, divergence-coefficient (-factor) aK, aμ, aγ

  • ƒ( σ1, ρb) =

    DENSITY FUNCTION



  • ƒ( σ1, σc) =

    FLOW FUNCTION

    FL, ffc

  • ƒ( φe, ρb, μw, silo geometry ) =

    SILO STRESS CONDITIONS

    Pv, Ph, Pw for rotation-symmetric, axially-symmetrical and conical silos

  • ƒ( φe, ρb, μw, σc, silo geometry ),

    BRIDGING

    , critical bridging area, pressure on the outlet

CUSTOMER LOGIN:

The accomplishment of the measurements is up to two weeks, after receipt of the materials. Then, we submit the login data. Then, you may retrieve all the measurements and evaluations, edit or customise them according to your needs, and print or save them.