A powder feeder can improve your system efficiency by metering the right amount of materials from the ingredient source—such as a bulk bag or another container—into a mixer or another downstream process. Many ingredients can be challenging to work with, and knowing how to customize your powder feeder can prevent flow problems like clogging, flushing and inaccurate measurement.
How to Customize Your Powder Feeder
An experienced engineer can help you customize your powder feeder to prevent common problems that might affect your materials. However, your engineer must know some critical information about your system and ingredients to get started. As you consider customizing your powder feeder, the following information will be helpful. These don’t have to be exact, but more accuracy will mean better system customization.
- Material properties: angle of repose, viscosity, fat content, moisture content
- Volume: how much of the ingredient are you measuring in what time frame?
- Accuracy: what is your margin of error?
- Dimensions: what is the available horizontal and vertical space around the system?
- Environment: are the temperature and humidity conditions stable, or will they change as the weather changes?
Type of Feeder
There are many ways to customize your powder feeder, and this starts with two different types of feeders. Each uses a different method for moving the materials through the feeder. The first, a vibratory feeder, uses vibration to move materials. A vibratory powder feeder can be effective for many ingredients, but it can also introduce noise and interference to the surrounding system. This can disrupt weight and volume measurements.
The second, an auger feeder, uses mechanical force from either a spring or a screw-shaped shaft. An auger feeder is highly versatile and preferable for most ingredients. There are many ways to customize this powder feeder further to perfectly suit the materials and the surrounding system.
The Feeder Core
You can customize powder feeders using augers with a spiral core or a shaft core. In a spiral auger, a spring inside the powder feeder creates the mechanical motion needed to move the material. In a shaft core, also called a screw auger, the flights around the core rotate and move the material. Either of these types of powder feeders can be effective. If your material is likely to bridge or clump, a screw auger can provide the additional movement needed to keep the material flowing.
Screw Auger Flighting
If you are using a screw auger powder feeder, you can customize the size, type and arrangement of the screw flights. The spacing between the flights, called the pitch, will partially determine how much material moves through the feeder. At full pitch, the spacing between the flights is equal to the diameter of the feeder. At half pitch, the spaces between the flights is half of the diameter of the feeder.
The screw auger flighting pitch will not only determine how much material moves through the feeder, but also the rate at which it moves. A full-pitch feeder will release a larger amount of material in slower intervals, while a half-pitch feeder will release a smaller amount of ingredients, but in faster intervals. This will change the overall flow of the ingredients through the system. Higher pitch will feed material in pulses, while lower pitch will create more continuous movement.
In a screw auger, it is important to alternate the pitch of the flights at the start of the feeder. If the flights are spaced and sized equally throughout, pressure will build up at one end of the feeder as it moves material. This requires the drive to work much harder than it needs to. Simply starting with half pitch and moving to full pitch will help to equalize the pressure across the screw auger. Conical-shaped flighting across the auger or variable pitch at the inlet will also solve this problem.
Diameter of Feeder and Auger Shaft
The feeder diameter is another obvious way to customize your powder feeder. Changing the feeder diameter will change how much material moves through it. When working with a screw auger, it is also important to consider the auger shaft. Widening the auger shaft will cause it to take up more space in the feeder, allowing less material to move through.
The ideal diameter of the feeder and the auger shaft will both depend on the desired volume. If the material must be carefully metered with more accuracy, a smaller feeder diameter or a larger auger shaft will move smaller amounts of material more steadily. However, if you want to move material through the feeder quickly, a larger feeder diameter and a thinner shaft will be best.
The drive on the powder feeder must be powerful enough to drive the screw or spring auger while delivering the right RPMs. The drive must also be accessible for maintenance or repairs. You can customize your powder feeder drive by changing the mounting position of the drive, the reducer, and the RPMs of the drive. This is another way to customize your powder feeder according to the material moving through it. Raising the RPMs will move material at a faster rate, and vice-versa.
There are many ways to customize your powder feeder to suit your materials and your overall process. This can seem complicated, however it also presents a number of different solutions if you encounter a problem with your particular ingredients or process. If your process repeatedly stalls at the feeder stage, or material moves too quickly or too slowly through the feeder, consider these customization options. Work with an experienced equipment manufacturer to ensure your powder feeder works with your materials, not against them.