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Thread: Improvement of Silo Discharge Rates

  1. #11

    Application Assistance

    If you can send some good photos of the inside of the silo I can offer our assistance for some air cannon placement.

    Air cannons are very affective when timers and placement are set up correctly. I can help achieve maximum flow rates at any level.

    Use this email for reply

  2. Dear D.,

    Thank you for your private message, but thye system is still not working properly. Please send e-mails to this address and I will try answering you promptly:

    Have a great week.

    Ralf Weiser

  3. Thumbs up Improvements In Silo Discharge Rates

    To both maximise on discharge rates and also to prevent material build up on the side wall you should try installing cleaners which keep the material 'excited' without causing any structural damage. Typically higher frequency acoustic cleaners such as the PAS-350 and PAS-230 are installed near the outlet of the silo (see attached photo) and powerful, our frequency Models such as the PAS-75 or PAS-60 installed on top (again see photo). For further information and to complete silo questionnaire please go to the following site -

    Best regards
    Donald Cameron
    Primasonics International
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  4. Have you contacted IBAU or Claudius Peters for thier advice

    The silo is squat...others have commented on the airslide spacing.......maybe the designer/suppliers tried to limit costs by limit airslides.

    We had issues with a silo for raw meal - we ended up with MORE aeration and also split the aearated sections - as the air will flow to the region of least resistance....what is the type of fabric - cloth or needlefelt....

    What happens at 5000T residual - is this a step drop or a gradual drop off in rate...???

    Do you have a standby blower that our could program to run all the time...

    Can you experiment with the aearation pattern/sequence and timing...

    You say that have a acone/hood over the central outlet - how do you de-dust the volume - you are adding air....either it comes out with the product or you have to vent it.

    You should try some experiments and see what happens


  5. Silo Discharge

    In my view the geometry of the air slides and the fluidisation velocity achieved needs attention.

    The surface area of the 448 airslides covers some 24 % of the silo bottom. In our experience , a coverage of approx 50% is needed to get the air to distribute and fluidise evenly .

    Next , the airvelocity with 3 x 600 m3/hr into 8 segments of 56 airslides each gives approx 0.018 m/sec airvelocity . For a heavy material as alumina , this may not be adequate to fluidise adequately . An estimate of appropriate fluidisation velocity will need data on particle size and pure density - but a rough guess will be some 0.03 - 0.04 m/sec air velocity out of the airslides when 50% aeration coverage is achieved on the silo base. If the blowers have speed tolerance available - changing the motors to higher power and modifying pulley ratio may help in raising airvolume keeping the blowers in place . For 50% coverage , more blowers must be put in tandem .

    Since the aeration is segmented, the material will aerate in columns - and collapse - as the segments switch . So the output will not be uniform . But this is phenomena in almost all segmented silo extraction systems . Increasing the number of segments will improve this behaviour - but it is a matter of cost - and what is the downstream equipment into which the extracted material go into .
    Benukrishna Mandal

    Management and Engineering Advisor

    Email :

  6. #16

    Thumbs up Bottleneck with extraction from Alumina Silo

    Quote Originally Posted by D.NITHYANANDAN. View Post

    Sub.: Silo discharge rate- Reg.

    We have a ship loading system and handling Alumina. Our system is designed for 2000 MT/hr. We store Alumina in a concrete silo of storing capacity 22000 MT. While loading a ship, we could not extract more than 1000 MT/hr., and once the Alumina inside the silo reaches 5000 MT, we could not extract more than 400 MT/hr. from the silo. Other details in this regard are as follows,

    Material handled : Calcined Alumina
    Bulk density : 1.04 t/cu.m
    Angle of repose : 22 deg.
    Angle of surcharge : 10 deg.
    Granulometry : Dry and Sandy
    Size : -125 microns

    Concrete in construction with flat bottom
    Diameter 35 m
    Wall thickness 350 mm
    Height 33 m
    Storing capacity 22000 MT
    About 450 nos. of open Air slides of size 200 mm wide x 2.5 m long x 100 mm height are installed at 8 deg. Slope on silo floor. These 450 Air slides are divided into 8 segments for aeration (56 Air slides in each segment)
    Aeration is through cyclic PCV’s for opposite segments at a time (2 segments in total) for a period of 5 min.
    Silo discharge is through a distributor of Dia. 3 m with synthetic fabric installed at the centre of silo and 4 nos. of Flow Control Gates.
    A Steel cone is installed above the distributor in such a way that 1m gap is maintained between silo floor and cone plate.

    Root Blowers
    Pressure : 0.63 bar
    Volume : 600 cu.m/hr.
    No. Of blowers : 3

    Our queries are:
    1. How to improve the discharge rate
    2. How to improve the discharge rate once the silo stock reaches 5000 MT
    3. How to reduce the substantial qty. of dead stock inside the silo (about 1000 MT)
    Dear Sir

    From your problem it seems you are located in Southern part of India (in AP) and if I am right I have already visited your port and had discussed simple solutions with your HOD.

    However we can undertake the project to ensure that you obtain the correct silo extraction rates.

    I would request that you may kindly contact us directly by e-mail : Be rest assured that we have the solution to your problem. If I guessed you correctly, I had also discussed (at your port) issues related to the telescopic chute of the ship loader.

    Thanks & Best Regards
    Anirban Bhattacharya
    Managing Director
    HP # +91-99-1025-8259
    Frigate Teknologies Pvt Ltd
    E-Mail :
    Web :

  7. HI,friends.

    I think we must know the reason why it can't reach.
    some reasons: self-flowing angle.

    Best regards
    Joe Zhou
    Mobile: 0086 15995118285

  8. #18
    Join Date
    Nov 14

    sonic horn

    you can't get enough flow out of the silo.
    is it caused by bridging and ratholing in silo? if it happens in your silo, definitely you will not get the designed data.
    acoustic cleaning by sonic horn is a good idea.
    you can get smooth material flow and even discharge with it.
    Last edited by Gary Blenkhorn; 8th August 2019 at 16:31. Reason: removed advertising link
    sonic horn, soot blower.

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