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Thread: Powder Flow - Coatings

  1. #1

    powder flow - coatings

    Hi all,

    we manufacture weigh scales, and have recently been given a contract to weigh & batch powders. The problem is some powders 'cling' to the sides of the weigh hoppers upon discharge.

    Does anyone know of a coating that will stop the 'cling'and allow pretty much all powders to 'slide free' with out a buld up: 'caking'?

    thanks..

    Paul Shepherdson

  2. #2
    Author Guest

    Powder Flow Coatings

    Hello

    For this application we recommend a PTFE coating.
    Please, send us some details about the geometry, dimensions, wall thickness, etc.
    Another solution would be a UHMW PE or PTFE lining.

    VATIS
    info@vatis.be

  3. #3
    Join Date
    Feb 03
    Posts
    5

    Removing coating of materials from weigh hopper

    We have successfully applied our single impact air piston vibrators to similar applications. The single impact air piston vibrator is configured so that the piston travels from the top of the vibrator to the bottom (base) of the vibrator. This creates a single kinetic impulse very similar to a single hammer blow, causing the material to fall off the wall. There may be no need to use an interior coating, however, if desired, an interior coating can be considered. This type of vibrator has a very high force output and yet uses very low amounts of utility.
    Please refer to our web site www.navco.org

    Sincerely,

    Ross M. Jamison
    Sales Manager
    NAVCO
    E-mail:ross@navc-jvi.com
    Sincerely,


    Ross M. Jamison

  4. reducing residue

    The powders will adhere to the surface of weigh contaienrs considerably more if the contents do not discharge in a mass flow pattern. Powder coating products are notoriously cohesive, so a non-mass flow container will tend to retain a thick bed on the walls, assuming the central region will fall out, whereas the wall slip generated by mass flow will wipe the walls and leave a relatively clear surface The optimum contact surface should be determined by wall friction tests. We have found a 2B finish stainless steel quite adequate for feeder hoppers, but a ptfe coating may offer slighly cleaner results, if the expense is justified.

    A vibrator may be useful for releasing a final dust film from the surface, but is more often used as an expedient for inneffective design than a necessary adjunct for a well designed unit.

  5. #5
    Thanks for teh responces.

    A vibrator or 'impact' is oput of teh question, as these hoppes are sitting on a loadcell, and the vibration / impact would damage teh loadcell.

    So a liner, or a spray is teh only real alternative.

  6. #6
    Join Date
    Feb 03
    Posts
    5
    Dear Lyn Bates,

    NAVCO has successfully applied linear vibration to other hoppers and bins with load cells. High amplitude, low frequency does not effect laod cells. We also manufacture vibrating tables with load cells on them for weighing applications with good success.


    Sincerely,


    Ross M. Jamison
    Sales Manager
    NAVCO

    ross@navco-jvi.com
    Sincerely,


    Ross M. Jamison

  7. avoiding residue

    The best bet would be to send a drawing or sketch so that I can see the geometry of the equipment and advise. If possible, mark the location and degree of residue. Send to lyn@ajax.co.uk or fax 44 (0)1204 386 723.

    regrads,

    Lyn

  8. #8
    2kg loadcell?
    500g material max?

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