Screw Conveyor vs. Screw Feeder
Posted on Wednesday Jul 31, 2019 at 04:03AM in Belting & Conveyors
Article By: Danny Clark
Business Unit Manager
"When buying a screw conveyor, how do you know if you need a standard screw conveyor or a screw feeder instead?"
This is a very common question asked by many folks within the industry. Many users ranging from engineers, buyers, and other end users are often unaware there is a difference between the two. You can avoid one of the most common mistakes made in designing a screw conveyor system by understanding the difference between a screw conveyor and a screw feeder. In this article we will briefly compare the two and the role they play in a screw conveyor system.
Screw conveyor systems: Frequently used for unloading bulk materials from rail cars, bins or piles. They are commonly found in cement and lime processing plants, aggregate plants, mining, grain storage plants, feed mills, chemical plants, food processing plants, and many more.
Screw conveyors: Simply move the material from point A to Point B. The inlet of a screw conveyor will always be control fed by another device such as: another screw conveyor, screw feeder, belt conveyor, bucket elevator, rotary airlock or a volumetric feeder. They can be used up and down inclines. Mixing, cooling, and heating materials can also be done with a standard screw conveyor. These can also be referred to as a “transfer conveyor” in the industry. They are typically designed to convey bulk materials at 15, 30 or 45 percent trough loading, depending on the material characteristics. They are available in a wide range of sizes, lengths, configurations and material of construction.
Screw Feeders: Designed to meter bulk materials and are typically located at the beginning of a process. The capacity or feed rate of the conveyor system can be accurately controlled with screw feeders. The inlet of a screw feeder is always flood loaded (100-percent full) and typically it will be mounted directly under a hopper, a bin or a silo. With the inlet being flood loaded, the design of the screw in the inlet area and screw speed determine the capacity or feed rate. They are also available in a variety of sizes, lengths, configurations and material of construction. However, typically most screw feeders are less than 20 feet in length because the use of hanger bearings are not recommended. So, in very simple terms: The inlet of a screw conveyor is always control loaded and the inlet of a screw feeder will always be flood loaded.
Example of a Screw Conveyor
Example of a Screw Feeder
If you are interested in receiving a quote on your latest screw conveyor needs, contact one of our local sales representatives and provide us the answers to screw conveyor survey below. These six questions must be answered in order to accurately size out a screw conveyor and make sure your system is getting properly designed to fit your needs.
- (in cubic feet per hour, tons per hour or bushels per hour)
- 2.)What is the Length?
- (Inlet-to-discharge or overall length)
- 3.) Is it Horizontal or Inclined?
- (If inclined, what is the degree of angle?)
- 4.) How will it be loaded?
- (If flood fed, what is the size of the inlet?)
- 5.) What Material is to be conveyed?
- (Material type, weight, maximum lump size, and temperature)
- 6.) What is the Material of Construction?
- (Mild steel, stainless steel, special paint requirements, & etc.)