Results 1 to 2 of 2

Thread: Calculating Slip Angle in Hoppers

  1. #1
    Pål Gjerde Guest

    Calculating slip angel in hoppers

    Do anyone have any simpel way of calculating the slip angel in a mass flow hopper ?

    I suggest the size of the hopper is D < H < 4D (that means diameter is smaller than height and height is lower than four times the diameter)

    Best reg Pål G

  2. Mass Flow wall angle

    The ‘slip angle’ for a mass flow hopper depends mainly upon the wall friction between the bulk material and the material of construction of the converging section of the hopper wall. It is also influenced to an extent by the internal angle of friction of the bulk material. The relationships are given in Jenike’s Bull. 123, Univ. of Utah experimental station 1964 and also in the British Materials Handling Board Guide to the design of hoppers, silos bins and bunkers, published by BSI.

    Simplified charts showing this information for Conical and Vee hoppers are given in an Ajax Equipment technical paper – ‘Storage and Feeding of Particulate Solids’. This publication also includes a crude ‘rule of thumb’ formulae for conical, pyramid and Vee hoppers, based on wall friction measurements only, that is normally within 2 or 3 degrees of the value derived from a more detailed investigation. This is useful as a quick guide to the requirements for basic evaluation and site planning. If you care to send your postal or email address to, a copy of these items will be sent forward.

    I would emphasise the importance of securing representative samples of both the wall contact material and of the range of condition of the product to be stored, to determine the upper and lower bounds of friction. It is also good practice to employ a wall friction measuring tool that can record, if necessary, static friction under instantaneous and time consolidated conditions and dynamic friction at various slip velocities as the hopper has to accommodate all circumstances of product and operational variations. The test machine should preferably have a long stroke so that all the readings in a series can be taken at one ‘run’. One such device with these facilities can be seen on the web site of

    Lyn Bates

Similar Threads

  1. Acoustic Cleaners for Silos & Hoppers
    By donaldfcameron in forum Silos, Hoppers, Bins, Bunkers & Domes
    Replies: 5
    Last Post: 23rd August 2005, 13:29
  2. Angle of Conveying Testing needed
    By todds in forum Trough Belt Conveying
    Replies: 4
    Last Post: 17th June 2002, 14:38
  3. Internal cleaning of hoppers
    By Author in forum New Projects, Tenders, Inquiries
    Replies: 0
    Last Post: 6th March 2002, 20:11
  4. A/2000 Silos, Hoppers, Bins & Domes Vols. I-IV
    By Author in forum Publications, Standards, Patents, Catalogs
    Replies: 2
    Last Post: 22nd November 2000, 10:17
  5. Flow in Hoppers
    By Pjaynes in forum General Aspects
    Replies: 5
    Last Post: 13th November 2000, 8:02

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Single Sign On provided by vBSSO