installation of storage silos

Hello and welcome chemengg:

Can you rephrase your question?

I do not know what you mean, with ref' to a silo or grain storage, by "angle of repose"?

Do you mind telling me what country you are from, and, what makes you think all grain stores are on high ground?

all i need to know is that are all storage silos (for storing powdered product) installed at a height above the ground level? coz the majority of the silos that i've come across are not on the ground.

about the angle of repose - the base of these silos that i've come across are conical. does it have something to do with the angle of repose? (i.e the angle that the powder pile will make with the horizontal)

if you have any answers plz reply

i have rephrased the question for your better understanding. hope you are able to come up with an answer now!

Hello chemengg:,

I understand what you mean by angle thing now. Go to the first site here and go through the different links and you will see grain id stored above ground, below ground, and in just about any container that comes in useful.

By the way, I found this by pasting your entire original post into google!

• Grain storage techniques ... - Bulk storage - Factors influencing ...
• For a given volume of storage, the lower the height of the walls, ... bottoms ( which are usually suspended above ground level) and the risks of ground water ...
  www.fao.org/docrep/T1838E/T1838E19.htm - 31k - Cached - Similar pages
• AE-93 The silo must have a concrete floor, preferably built to a height above that .... If the grain is in any manner out of condition, the angle of repose may be ...
  www.ces.purdue.edu/extmedia/AE/AE-93.html - 29k - Cached - Similar pages
• 
  by AW Tank
• [PDF] Silo Patrol File Format: PDF/Adobe Acrobat - View as HTML
  We realize that you do have a choice of vendors. when procuring level measurement ... 2) Placement - Consider the affect that the material's angle of ...
  www.conasen.com/cn/download/344A%20SiloPatrol%20SMU%20I&O.pdf - Similar pages
• [PDF] Discharge Aids File Format: PDF/Adobe Acrobat - View as HTML
  The 'Angle of repose' is NOT a basis for silo design ...... Understand process requirements: installation (existing vs. new silos), height ...
  www.shapa.co.uk/pdf/techdata12.pdf - Similar pages
• Hopper Pull-out Forces - Forums 28 Jul 2006 ... The front wall height (above the belt)...should be LESS ie LOWER than ... have been checked and are o.k. material angle of repose is 30-35°. ...
  www.bulk-online.com/Forum/showthread.php?threadid=7994 - 81k - Cached - Similar pages
• Underground Mining and Its Surface Effects - Geotechnical Hazards ... 29 Oct 2008 ... M= excavated height phi = angle of repose of caved material .... have been defined by Janelid and Kvapil (1966) based on silo studies. ...
  www.fhwa.dot.gov/engineering/geotech/hazards/mine/workshops/iawkshp/betourna2.cfm - 76k - Cached - Similar pages
• Full text of "Bituminous coal storage practice" Silos are usually set high enough above the ground so that the coal can be ...... Ft. in Lbs. Angle of Repose in Degrees REMARKS Robins Conveying Belt Co . ...
  www.archive.org/stream/bituminouscoalst00stoerich/bituminouscoalst00stoerich_djvu.txt - 251k - Cached - Similar pages
• Powders and Granular Materials surface to the horizontal is called an angle of repose. ..... Schulze, Storage of powders and bulk solids in silos, URL http://www.dietmar-schulze. ...
  doi.wiley.com/10.1002/9780470995792.ch5 - Similar pages
• PII: S0009-2509(96)00453-8 Particles are fed into this vessel through a flexible. hose from a storage vessel above the equipment and. collected in a large bucket at ground level. ...
  linkinghub.elsevier.com/retrieve/pii/S0009250996004538 - Similar pages
  by JF MacDonald - 1997 - Cited by 12 - Related articles Take care.......................

In most cases the content has to be transported to an other place. If the silo has a height over ground one can push a "box" under the opening and let the content flow in it. This for the height. Now for the angle the answer will be yes and no. Yes the angle has to be higher than the natural slope so that all content can come out but there is an other reason too powder builds up due to friction between particles "bridges". The higher the angle versus horizontal the bigger the 'radius " of the bridge and less pressure is needed to pass through. It is a rough, simplified explanation but physically correct.

Now may I make a remark, you came to get an answer to a question and your question lead a participant to a request for more details this is not a reason to use a not very pleasant tone with him. Understand that what is clear to you may be not as clear as you think to another since we do use different words with different meanings because of the different countries we come from. If you deserve respect and will get an answer the other deserve also respect.

Most silos I've dealt with are for asphalt or bag-house fines. the reason for them being above ground level is to load the material into the back of trucks. The usual angle of repose is 40% in the bottom of the silo.

your answers are very helpful! thanks! i've been able to get a more clear picture.