Screw Conveyor

Screw conveyors are one of the most reliable and cost-effective methods for conveying bulk materials. Due to their versatility, screw conveyors can convey a wide variety of bulk materials ranging from dry, free-flowing Portland cement to wet, sluggish dewatered bio solids.
Screw conveyors can be designed to operate in almost any position, from horizontal to vertical. Inclined screw conveyors are used to convey and elevate bulk materials from one level to another. Depending upon the bulk material and the objective, proper design and construction of an inclined screw conveyor will provide many years of uninterrupted service and productivity. The purpose of this article is to help the reader understand the basics of inclined screw conveyor design for various applications.

A screw conveyor consists essentially of a shaft mounted screw rotating in a trough and a drive unit for running the shaft. The material is moved forward along the axis of the trough by the thrust of screw thread or flight. The trough is usually of the U-shape.
A helical blade is attached to a drive shaft which is coupled to a drive unit. The shaft is supported by two end bearings and intermediate bearings. The U-shaped trough has a cover plate with an opening for loading the conveyor. A discharge opening is provided at the bottom of the trough. The loading and discharging points can be located anywhere along the trough. More than one feed hopper and discharge hopper may be fitted according to the necessity.

Conveyor systems are commonly used in many industries, including the Pan Masala, automotive, agricultural, computer, electronic, food processing, pharmaceutical, chemical, bottling and canning, print finishing and packaging. Although a wide variety of materials can be conveyed, some of the most common include food items such as beans and nuts, bottles and cans, automotive components, scrap metal, pills and powders, wood and furniture and grain and animal feed. The principle of material movement along the trough is similar to the sliding motion of a nut along a rotating screw when the nut is not allowed to rotate. The weight of the material and the friction of the material against the wall prevent the load from rotating with the screw