For screw conveyors you may purchase CEMA publications here :-

http://www.cemanet.org/publications/index.html

There are also very useful papers available for purchase here :-

http://www.ajax.co.uk/papers.htm#p1 ■

See The British Materials Handling Board publications: -

‘Guide to the Design, Selection and Application of Screw Feeders’- by Lyn Bates

ISBN 1 86058 285 0 Published by

Professional Engineering Publications

‘Economic Guide to the Design of Circular Metal Silos’- by Michael J. Rotter

ISBN 0 419 23460 8 Published by SPON Press ■