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Prabir Datta. A short summary of this paper. This book may not be reproduced in any form without written permission from the Conveyor Equipment Manufacturers Association. Engineering Conference Belt conveyors for bulk materials. Includes index. Belt conveyors. Bulk solids handling. Experienced conveyor engineers can use the information and engineering principals put forth to design virtually any width, length, configuration and capacity of bulk materials handling belt conveyor and predict its performance within an acceptable range.

Interested parties can also gain a basic understanding of the engineering, selection of components, related equipment and accessories and applications for belt conveyors. The information presented in this book is intended to cover the basic principles of belt conveyor design and to include such formulas, tables, charts and recommendations as are required to design most belt conveyors. The material is arranged in the order most convenient for the use of an experienced conveyor engineer.

As always, the responsibility for the ultimate safety, reliability, and functionality of any conveyor system rests with those who design and build it. While the formulas, recommendations and data are based on industry practice and are believed to be reliable, CEMA does not, and can not, assume any role in, or responsibility for, the safety, reliability or functionality of any conveyor system or component which it did not design.

The formulas and principles in this book are guidelines only and are applicable to the design of a high percentage of conveyors that are required to operate under reasonably normal conditions. However, conveyor design is as much art as it is science and some conveyors will operate under conditions that are beyond the scope of this book.

These design challenges require broad experience for a satisfactory solution. Including safety labels and guidelines, posters, videos, and more resources. All Technical Downloads. Download PDF.

Screw Conveyor Downloads. Conveyor Bulk Belt Accessories Downloads. Are you interested in becoming a CEMA member? It appears, though, that this method of ship propulsion was at once a victim of tech- nological obsolescence brought on by the success of paddle wheels. During the many centuries of individual or small group self-sufficiency follow- ing the days of Archimedes, there was little need for continuous mechanical handling devices because there was little need for volume production, and even if there had been, there was no satisfactory source of power available.

It was about years later that screw conveyors again were proposed, when it became imperative that some means be found to handle mechanically the grain harvests made necessary to serve the needs of the rapidly growing American popu- lation. In , the man who might be called the patron saint of mechanized materials handling, Oliver Evans, laid out on paper his first mechanized flour mill which incorpo- rated not only screw conveyors but bucket elevators and belt conveyors as well.

All these devices were tied together by a system of wooden toothed gears, wooden pulley and leather belts, and all were driven from a single water wheel. The first mill built by Evans in actually was a reconstruction of a mill thought by some to have been built by his grandfather.

The screw conveyor as first designed by Evans consisted of a round wooden core on which were mounted in helical form a series of wooden plows or flattened wooden pegs. Appropriate sliding gates in the trough bottom could be opened to deliver grain to the mills as needed. Soon, though, Evans improved on his design by making the screws of heli- cally formed sheet metal sections mounted on a wooden core that might be anywhere from five to twenty feet long.

The mill is in running order and has all of the types of conveyors that Evans used, including screw conveyors with wooden flights on wooden cores on which wrought iron journals were pressed. During this period the country grain elevator evolved of necessity to handle what then was thought to be vast volumes of grain needed by the growing and hungry population.

The technology of mechanization was keeping pace with the demands of the spreading population. The metal screw conveyor flights were originally of the sectional flight variety, formed from flat sheets cut in circular form with a hole in the center then split on one side and the two edges pulled apart to form one flight section of a screw.

Successive flights were then joined by riveting, shingle fashion, to make a continuous helix of whatever length was called for. At some unknown date, the wooden core was re- placed by an iron pipe when the proper sizes of such pipes became available. The next technological advancement of importance in screw conveyor design was patented March 29, , by Frank C.

Caldwell under patent number This was a continuous, one piece screw flight formed by rolling a continuous strip of steel into a helix. Both types of screws are still produced. Early screw conveyors used wooden bearings and there are still applications where such bearings are specified. Cast iron support hangers for the bearings and cast iron trough ends came along with the all-metal screws.

Since the screw conveyor came into general use a little over a century ago for moving grains, fine coal and other bulk material of the times, it has come to occupy a unique place in a growing area in the general field of materials handling and processing. Many refinements in design, materials and methods have come into general use. Weld- ing has supplanted rivets to provide smooth conveying surfaces along with greater strength and rigidity in screws and troughs.

Ball bearings for hangers have become less bulky so they now occupy little more space than did the older plain sleeve bear- ings.

Such bearings in the box or trough ends provide improved thrust capacity. Im- proved methods of sealing to keep out foreign materials and to retain lubricants have greatly expanded the use of anti-friction bearings in screw conveyors. Enclosed drive speed reduction units in place of open gearing greatly reduces hazards to workmen and reduces maintenance work largely to a matter of periodic inspection.

The screw conveyor engineer has a tremendous latitude in the selection of materials to best meet the operating conditions of a particular conveying job, when it falls outside the broad capabilities of standard screws made of ordinary steel.

Whole new families of bulk products are being handled as a matter of course today that were not even thought of just a few years ago, and the advance of technol- ogy is such that additional new products are being discovered and developed almost daily for industrial and agricultural use.

Many such products are toxic to human beings, or are toxic at certain stages of their processing. Others are merely irritating or un- pleasant to work around. Screw conveyors often are the answer to handling these products.