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Thread: Dosing of Power into Vessel Under Vacuum

  1. #1
    andreashansen Guest

    Dosing of Power into Vessel Under Vacuum

    Hi all,

    I am looking for a practical solution for continuos metering (weighing, ~1000kg/h) of powder into to a vessel which in operated under vacuum (800mbara).

    Does anything have experience dosing powder into a vacuum vessel without having excessive air ingress from the powder metering system to the vessel itself?

    I would like to avoid a loss-in-weight system due to the requirement of a large volume on weighing cells.

    Media is diatomic earth (incompressible) with varying bulk density.

    Hope to achieve +/-5% accuracy on the metering capacity.

    Thank you in advance for your replies.

    /Andreas

  2. #2
    Teus Tuinenburg

    Professional Experience 58 Years / 8 Month Teus Tuinenburg has 58 Years and 8 Month professional experience

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    Dear Andreas,

    A valve lock might be a solution.

    Although, this is a volumetric dosing system, and you require a mass dosing system.

    For a mass dosing system, the (small) batches must be weighed.

    The weighed batch is dropped into the valve lock.

    This system can be made quasi continuous by a parallel weighing and feeding.

    A better way is to consult a well know company in this field.
    Teus

  3. #3
    andreashansen Guest
    Quote Originally Posted by Teus Tuinenburg View Post
    Dear Andreas,

    A valve lock might be a solution.

    Although, this is a volumetric dosing system, and you require a mass dosing system.
    Dear Teus,

    Thank you very much for the reply.

    I am normally using a valve lock system; two systems in parallel (one in filling one in emptying).

    Since the powder is dosed to a continuous process, I have a desire to keep the dosing as "continuous as possible"

    A scaled-up valve lock system will act more abrupt since I will need larger valves (with longer opening times) to meet the capacity of 1000kg/h @ 300kg/m3.

    It might be worth to consider your approach with a valve lock system, with intermediate weighing hopper, working quasi continuous - In fact maybe having several lock valve systems can help to smooth the "continuous" dosing.

  4. #4
    Teus Tuinenburg

    Professional Experience 58 Years / 8 Month Teus Tuinenburg has 58 Years and 8 Month professional experience

    Discussions 271 Teus Tuinenburg acceded to 271 discussions, Publications 0 Teus Tuinenburg Tuinenburg released 0 publications

    Know-How Conveying (1510) Teus Tuinenburg used this tag 1510 times, Pneumatic Conveying (1302) Teus Tuinenburg used this tag 1302 times, Pneumatic (578) Teus Tuinenburg used this tag 578 times

    Dear Andreas,

    Since you are feeding from the atmosphere to a vacuum region, a control gate is also a possibility.

    The pressure difference is determining the flow through an adjustable/controlled gate opening.

    https://www.ibauhamburg.com/en/compo...-control-gate/

    Probably, you also need an intermediate hopper between the weighing scale and the control gate.

    The level in the hopper is the basis for the control gate opening as the weighing scale is feeding at a constant rate.
    Teus

  5. #5
    Diatomaceous earth will settle quickly in a vacuum to a high density and is cohesive as a fine powder, so will need a well-designed, mass flow volumetric feeder to feed reliably and accurately. This could be fed from a lock system where air is evacuated and supplied on call from a level detector. One would need details of feed rate and local set-up to go into more detail.

  6. #6
    Teus Tuinenburg

    Professional Experience 58 Years / 8 Month Teus Tuinenburg has 58 Years and 8 Month professional experience

    Discussions 271 Teus Tuinenburg acceded to 271 discussions, Publications 0 Teus Tuinenburg Tuinenburg released 0 publications

    Know-How Conveying (1510) Teus Tuinenburg used this tag 1510 times, Pneumatic Conveying (1302) Teus Tuinenburg used this tag 1302 times, Pneumatic (578) Teus Tuinenburg used this tag 578 times

    Dear Lyn,

    When a control gate is used (as I described it), the Diatomaceous earth enters the vacuum region aerated under the vacuum pressure.
    Or am I thinking too fast and too simple?
    Teus

  7. Magnetic Vibrating Feeder

    Hello,

    It would be possible to utilise a vibrating feeder inside a vacuum. I have experience of building such feeders utilising our Magnetic Vibrators.

    Please feel free to contact myself.

    fletcher@aviteq.co.uk

    Thanks,

    Paul

  8. #8
    A plug seal screw feeder can deliver material into a vacuum without ingress of air but, contrarily to feeding into a pressurised zone, the plug has to be restrained by a controlled pressure plate. Its an effective solution, but not for standard equipment.

  9. feed to undervacuup vessel

    Hi,
    As Teus saif airlock feeder is a solution

    I add following for system design
    Bunker
    Underbunker airlock or screw feeder (with FC driven)
    surge hopper with level sensor
    Small weighing bunker with 2 butterly valve (air tide) ( I used a dia 219mm pipe before)
    Automation to drop material by weighing (you can adjust stabile feed in automation). You take always avarage of last 10 weighing and adjust feed rate by control above units

    see Ball mill (or any mill) STABLE FEEDING system, 2017 KSA: https://youtu.be/oJmmy7Ay_Xg
    In this way you send material inside vakuum vessel in always same capacity kg/h ...
    Hope it is usefull
    Ertekin
    RTK

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