9th January 2002, 8:07
Dear Mr. Wohlbier,
Our company is one of the leading among Russian's firms in the
field of reconstruction and building of baking plants, including bulk
Before bulk handling systems were designed and produced by
Russian manufactures specializing in this field, who we invited as
coexecutors. However the equipment used by those manufactures and the
quality level of their work does not satisfy us and our clients anymore.
That is why we decided to deal with these problems ourselves.
Currently we are investigating this field and are searching for
different informational materials regarding different components
required for construction of pneumatic and vacuum conveying systems,
possible suppliers and calculation methods.
Thanks to the information located at your portal, we were able
to contact a number of companies manufacturing components and already
consider some of them as possible suppliers.
At the same time, we still have many questions to which we can
not find the necessary information.
On that account, we are asking for your help in finding
suppliers of the following components (see table) and recommendations
regarding literature, textbooks or information on construction and
calculation of modern pneumatic and vacuum conveying systems.
We thank you in advance for any help that you could provide.
Technical director of AGRO-3
Ball valve with actuator
Emergency vacuum relief valve
Sutter valve with pneumatic drive
9th January 2002, 13:11
The best book that I know of is : PNEUMATIC CONVEYING OF SOLIDS, A THEORETICAL AND PRACTICAL APPROACH, by GE Klinzing, RD Marcus, F Rizk and LS Leung. It is published by Chapman and Hall. Its ISBN is 0-412-72440-5.
David Mills has also written a good book on the subject but I do not have its details.
9th January 2002, 13:38
Books on Pneumatic Conveying
The book by Dr. Mills and Dr. Agarwal was published by
Trans Tech Publicatins Germany and has the following
bibliographic data (you will find contents pages etc.,
and also other interesting books on Pneumatic Conveying
in the Bookshop on this website.
Pneumatic Conveying Systems
Design, Selection, Operation and Troubleshooting With Particular Reference to Pulverised Fuel Ash
D. Mills and V.K. Agarwal
From the Foreword
Fly ash conveying tends to be a rather neglected subject area, particularly with regard to books. Such neglect is probably due, in part, to the near zero value of the commodity. Having worked in this particular area for many years, however, the authors have recognized a definite need for such a book. System design is not straightforward and errors in component specification tend to be made on a regular basis. A particular problem with fly ash is that the material is automatically graded in the collection hoppers in boiler plant, and different grades of fly ash can have very different conveying characteristics.
The efficient handling of fly ash, however, is essential for the smooth running of the associated power plant. If ash accumulations in boiler hoppers are not cleared, for any reason, the boiler plant will generally have to be shut down and the financial consequences can be quite considerable. Fly ash handling almost represents an industry on its own, with a multitude of companies involved in the design, installation and operation of conveying equipment. In India alone fly ash generation is rapidly approaching 100,000,000 tonne/yr and is set to continue rising at a high rate into the forseeable future.
Much confusion exists around the definition of dilute and dense phase conveying and so this is an issue that is addressed in detail. In general, in a conventional positive or negative pneumatic conveying system, coarse grades of ash can only be conveyed in dilute phase, and so high values of conveying air velocity must be employed, with the ash conveyed in suspension in the air. Fine ash, however, can usually be conveyed in dense phase, non suspension flow, and with very much lower conveying air velocities but this capability is dictated very much by the concentration of the ash in the air, the pressure drop available and the conveying distance.
The critical design parameter in any pneumatic conveying system is the conveying line inlet air velocity. With different grades of the same material requiring different values of this velocity, considerable care must be exercised in the design and specification of the plant and components if different grades are to be conveyed in a common system. An added problem is that the different grades of fly ash are generally at different temperatures and this adds to the complexity of specifying air requirements and calculating air velocity values. Yet another problem is the fact that fly ash is generally a very abrasive material and so component specification must take this into account also.
In systems where fly ash is drawn from ash hoppers to intermediate silos by vacuum conveying, and is then conveyed onward by positive pressure to bunkers for disposal, further problems can result in this onward conveying if a mix of both fine and coarse ash has to be handled. Emphasis is given to both system design and system operation in the book, and so problems of this nature are considered in two ways. For a new system the conveying variables are highlighted so that they should be taken into account in the system analysis and design procedures. For existing systems two chapters are devoted specifically to troubleshooting and numerous equations are presented throughout the book that can be used to check operating parameters. Stepped pipeline systems are a design feature that is given prominence, and this applies to both positive pressure and vacuum conveying systems. Several case studies are included to illustrate the design procedures for both fine and coarse ash, and these are used further to illustrate the basic fact that there is no one fixed set of design and conveying parameters for a given conveying system. An infinite combination of air supply pressures and pipeline bores is generally capable of meeting any conveying duty, limited only by the availability of standard pipeline bores and the problem of accommodating very high air supply pressures. It is to be recommended that alternative designs should be considered for any system and that these should be evaluated in terms of both capital costs and running costs. By this means a true economic cost comparison can be made, in which it should also be possible to include maintenance costs.
Much of the conveying data presented in the book was obtained by students running pneumatic conveying test facilities. This is why such high values of solids loading ratio and low values of conveying air velocity have been achieved in much of the work presented. The authors often state in short courses that anyone can convey fine fly ash and cite the case of our many students and their results in order to encourage delegates attending. From our experience with coarse ash, and visiting innumerable power plants where the ash is also at a high temperature, however, we do recognize the many problems and we hope that this book will help in gaining a clearer understanding of the issues, the design process and the operating problems.
Dr. David Mills
Dr. V.K. Agarwal
9th January 2002, 17:24
Pneumatic Conveying for Baking Plants
Thank you for your interest in our pneumatic conveying systems. We
manufacture a wide range of pneumatic conveying systems from rock and sand conveyors, seed conveyors for marmers, grain conveyors for grain terminals and ship unloaders for ports. Your "table" of component requirements was not attached. Please advise us of your requirement.
Christianson Systems, Inc
Blomkest, MN USA
Tel: 320-995-6141 ext 364
16th January 2002, 14:26
Our company provides considerable material handling equipment and systems for bakeries. Inclusive of Bulk Bag Unloading, Tubular Drag Conveyors, Helix Flexible Screw conveyors, Bag Dump Stations with Dust Collection, Pneumatic Conveyors, Batching Systems, etc. Visit our web site at www.hapman.com to see our equipment.
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