What are Screw Feeders?
Screw Feeders are designed to regulate the rate of flow (movement) of a bulk material, in different bulk handling industries, coming out of a bin or hopper. The largest section of, any Screw Feeder, is its inlet, which is designed to be flooded with material. This material could be liquid or non-liquid. The inlet is not fully covered, but rather has high curved walls. These curved walls are designed to keep the material inside and avoid material from spinning out of the inlet. Rationale, of not fully covering the inlet, is to have maximum control over the process.
Variants of Screw Feeders
There are different variants of Screw Feeders that are designed to realize different objectives. Not only do these variants differ in design, but also their role differs slightly. The design is standard; however, the modifications in the diameter, pitch, and inlet distinguish a Screw Feeder.
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Volumetric Screw Feeder
It is also known as Metering Screw Feeder, which is designed to flush out materials at a continuous pace. This Screw Feeder can flush powders and Fibrous particulate products, which provides us an understanding regarding its capacity to perform tasks. Because of its high accuracy, it is one of the preferred variants.
The design, of the Volumetric Screw Driver, is comprised of distinguished tapered conditioning chamber and a slow rotation agitator, which allow the capacity of the machine to augment. The various control functions give maximum control over the process. Also, a timer, with on/off settings, further simplifies the entire operation. Different features of the machine facilitate the machine to flush various kinds of materials. Because of the simplicity and utility of this variant, it is the most preferred variety of Screw Feeder. Also, it is economic, which further augments the demand for this type.
Typically, this variant is made up of carbon/stainless steel, which indicates that it is durable and because of its long lifespan, it is a good investment. When designing/buying a Screw Feeder, its utility, price, and durability are considered.
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Gravimetric
This variant is more sophisticated or technology-enabled than Volumetric Screw Feeder. It is designed to utilize feeder as the control point, which implies that it reads the reads the size/flow of material and judge it on the pre-set flow rates and also the minimum accumulation. Therefore, the pre-set values and the size of material regulate the operation of the machine. For instance, if the reading on the scale drops below the value which has been pre-set, the Helix is directed to feed more material. This detail depicts that machine operates semi-automatically and its design is quite sophisticated in contrast to Volumetric Screw Feeder.
What are they made out of?
Screw Feeders are of various types and as their types of change, so do the design and material, which they are made up of. The simplest of screwdrivers could be made of ordinary steel, and the inlet or trough could be made up of wood. However, commonly carbon-steel is used as it is stainless and it’s durable. The durability is the factor, which pushes the makers to make carbon-steel screw Feeders; however, the use of carbon steel, in the production of Screw Feeder (whether Volumetric or Gravimetric), increases the cost, especially in case of Gravimetric, which is already a very sophisticated machine.
How are they made?
Design, of the Screw Feeder, is quite standard; however, modifications may occur because of the nature of operation and material. Typically, a material is pushed into the inlet from the hopper/bin/Silo and rotated/pushed forward through the rotation of blades, which could be single or twin. The Screw is generally under the inlet, which rotates at different speeds, allowing more control over the process. In some designs, the inlet is simply a trough, which is designed to accommodate material to a certain volume. As per requirements, not only inlet/trough can be modified, but also the screw can also be altered (screw’s design/speed alteration) to meet the objectives. However, this entirely depends upon the objective(s). Other kinds of alterations are also possible, which include intentional tampering with flighting diameter, changes in pipe-diameter, alterations in trough design, etc.
The diameter, of a screw, provides characteristics to not only screw, but also to the overall machine. For instance, a screw, which has a uniform diameter and pitch, will first move that material, which is at the rear of the inlet. Because of this, uniform pitch and diameter, various kinds of issues may occur. The most frequent issue with such design is that it uses only a portion of the inlet or trough. As a consequence, the material is not discharged evenly by the bin or hopper. The residual material, which has not been properly discharged, clumps and degrades with time. It impacts the performance of a screw feeder. Therefore, the emphasis is on the design and details, such as diameter and pitch to avoid such issues and to ensure Mass Flow.
Selecting the Right Screw Feeder
First Consideration: The selection, of a Screw Feeder, comes down to the type of material, with which one would be dealing. The twin and single blade Screw Feeders can be used to handle various kinds of materials. Twin blades are used when the volume of material is high, and the objective is Mass Flow.
Second Consideration: Sophistication of operation is another consideration, which influences the decision of buying a particular type of Screw Feeder. For instance, for highly sophisticated and semi-automatic operations, Gravimetric Screw Feeder is used. However, for simpler operations, Volumetric Screw Feeder is preferred.
Third Condition: Price is another factor, which directly influences the decision of buying a particular Screw Feeder. For smaller industries with a limited budget, volumetric screw feeder with a single blade is appropriate. However, for more complex and large operations, Gravimetric Screw Feeder, with twin blade is more appropriate.
What Do You Look for in a Screw Feeder?
- Feature 1
The machine must have increased utility and excellent volumetric performance through an evolved design.
- Feature 2
The machine must be able to perform complex operations semi-automatically.
- Feature 3
Machine/Screw-Feeder must be simple to operate.
- Feature 4
Under pressure, the machine must not fail to perform as per standards.
- Feature 5
The machine, of particular designs and features, can be produced with a range of alloys.
- Feature 6
We can add improvements to the machine, in future, as per requirements.
Summary/Conclusion
Screw Feeders are used for flow of materials in a particular manner. Its design is quite standard, and it is comprised of a chamber, inlet/trough, screw (single or double) and gadgets to control the pace of the flow and operations. The number/diameter of screw and pitch gives characteristics to a Screw Feeder. The choice of a Screw Feeder is influenced by the types of operations, and what kinds of materials are to be handled. For instance, the volumetric screw feeder is simple, and it used to flush material are constant pace. Also, it can manage a range of material products. In contrast, Gravimetric Screw Feeder is sophisticated, which semi-autonomously controls operations through the pre-set values.
The decision, regarding Screw Feeder, depends primarily on the nature of the material and sophistication of operations. Also, the price is also a relevant factor.
