The screw conveyor is also called an industrial screw system or auger conveyor. It can be used for different industries. Let’s see in this, know it all about screw conveyors blog, what they are and where can they be used.
What is a Screw Conveyor?
A screw conveyor is a system designed to ease the transfer of both semi-dry and dry bulk materials. Whether the materials flow freely or not, it efficiently transports them between hoppers, rail cars, silos, vats, barrels, pits, and even trucks.
How is it installed?
A screw conveyor is a mechanism that makes use of a rotating helical screw installed in a trough or tube to move materials from one point to another. In modern industry, screw conveyors are often installed at a slight incline to make it more efficient to move material. An increase in the angle of inclination leads to a decrease in the capacity of the material being moved. To avoid having the material move backward, an angle of 45 degrees is the maximum one that should be used.
Which industry is it used in?
Many bulk handling industries use them, including mining, pharmaceutical, oil and gas, agricultural, chemical, plastic, food processing, and even construction.
What are the types of Screw Conveyor Designs?
Several types of screw conveyors are available. The designs also depend on the intent as well as the angle of inclination. They can also either be a blend of a few types or have their unique specifics determined by their manufacturer. Following are the four main types of screw conveyors:
Horizontal Screw Conveyors
It is by far the most common type of auger screw conveyor in use, owing to its practicality and ease of use. Horizontal screw conveyors come in many lengths, sizes, configurations and are made with different materials. Screw size standard length ranges from 1 to 60 ft. and is selected according to the type and characteristics of conveying material.
Vertical Screw Conveyors
Vertical screw conveyors are used to elevate bulk materials at extremely steep or even vertical inclines. Most manufacturers prefer any screw conveyor that is located on an incline above 45° to be vertical. Due to its compact setup, it can fit in tight spaces. It is a dependable, cost-effective solution as it has very few moving parts.
Inclined Screw Conveyors
As the name suggests, these conveyors operate at an incline from the horizontal, as long as it is below 45°. With an increasing degree of inclination, it needs higher horsepower, and the conveying efficiency is reduced. It is because of gravity and the risk of bulk material falling back. Other factors that affect the efficiency include the physical characteristics of the material being conveyed, the screw pitch, and the type of trough used in the screw conveyor.
Shaftless Screw Conveyors
This type of screw conveyor is specially designed to move materials that are difficult to convey, including those with high moisture content. Shaftless screw conveyor designs are meant to provide a conveying surface that will not clog. When conveying slow and sticky bulk materials, they offer improved efficiency and greater flexibility in the plant layout.
Flexible Screw Conveyors
Also called flexible augers or helical conveyors, they make operations very efficient for the facility in which they are used. This type of conveyor can bend in different directions and have its angles adjusted as necessary. It is different from stationary conveyors, which remain fixed throughout. Due to the flexibility, a flexible screw conveyor can be applied in many situations within a single facility.
What are the advantages of a Screw Conveyor?
Screw conveyors have a variety of advantages, some specific to the particular type of conveyor. Following are some general benefits of screw conveyors:
● They mix bulk material, breaking down large lumps and delivering consistent material to the delivery point.
● They are used in a variety of bulk material handling with different consistencies.
● They can have multiple discharge and inlet points, making them well suited to distribute bulk material over different collection points.
● They are compact and highly adaptable to congested spaces.
● They cause minimal spillage because they conduct bulk material in an enclosed system.
● They can be easily designed to serve as heat transfer units, thereby effectively heating, cooling, or even drying bulk material as it is moved.
What does a Screw Conveyor System consist of?
A screw conveyor system generally consists of the following parts:
● The conveyor screw, which is also called a spiral blade or flighting. It is held at one end to be controlled by the drive unit.
● The tubular casing that houses the conveyor screw is also called the screw conveyor trough.
● The drive unit
● Drive mechanism
How does a Screw Conveyor System work?
The system generally works by rotating the shaft which is held at one end and driven at the other. As it rotates, the material within the unit is moved forward along the bottom of the conveyor, pushed forward by the blade in the screw shaft. This is the basic principle, called the gravity method which depends on gravity to cause axial displacement of the bulk material. Subtle differences in design and specification lead to differences in working.
An alternative method is the push method which essentially moves material along spiral vanes in a nut-and-spiral-screw fashion.
Third method is the centrifugal induction method. It additionally uses centrifugal force to move material in steep vertical inclinations or with high rotation speeds.
When sourcing for a screw conveyor, it is important to explain your intended use to your supplier. Sodimate will make sure to deliver the right equipment for your specific needs, so it is necessary to discuss before settling on a purchase.