An important factor for the successful operation of any bucket elevator is how material is fed into the unit. To ensure consistent throughput rates, material should be fed in at a steady rate that results in optimal filling of the buckets. Underfilling or overfilling of the buckets is a symptom of poor feeding of the conveyor.
Feeders for Bucket Elevators: Types
When supplying a bucket elevator, UniTrak always considers how the unit will be fed. Many applications will not require the use of a feeder as the product is coming to the elevator from an upstream process. For example, product may be fed into an elevator from a mixer, or a pastillator. In these cases, the supply of product to the bucket elevator is controlled and regulated. However, if product is not being fed to the elevator by this method, then it is necessary to control the supply of product to the elevator inlet with the use of a feeder.
While there are many types of feeders for bucket elevators, our primary recommendation in many cases involves one of two types of feeders:
- Vibratory feeders
- Rotary valve feeders
We discuss each type in turn.
Vibratory feeders use both vibration and gravity to feed material into the bucket elevator. Gravity determines the direction of flow through the feeder, while a precisely regulated amount vibration is used to move the material.
Vibratory feeders work well for many material types, including those that are characterized as difficult-to-handle. A major advantage of vibratory feeders is that do not damage or degrade the material or product moving through the feeder. Given their propensity for no product damage, these types of feeders are a great match for the gentle handling characteristics of TipTrakTM bucket elevators.
A second advantage of vibratory feeders is their consistent feeding rates. Vibratory feeders avoid the “pulsing” or rhythmic feeding of material that is sometimes encountered with other feeder technologies.
Finally, vibratory feeders can offer a fully enclosed way to feed material into a bucket elevator. This feature can avoid issues such as product cross-contamination, dusting, etc.
Rotary valve feeders consist of a housing barrel containing rotating vanes that move material through the feeder. In applications using a bucket elevator, a rotary valve feeder can be used as a volumetric feeder to discharge bulk solid material from a hopper or bin directly into the conveyor.
Rotary valve feeders are available with round or square inlet and outlet flanges. For feeding TipTrakTMbucket elevators, UniTrak often recommends the use of a round flange, because it is often better to use a flexible connection between the feeder and the TipTrakTM. An advantage of rotary valve feeders is the wide range of service types available – standard and heavy duty models are available, as well as those designed for sanitary service and easy cleaning.
As with vibratory feeders, rotary valve feeders offer a fully enclosed feeding solution. This reduces the risk of material cross-contamination and the release of dust into the ambient environment.
Due to the nature of their design, where rotating vanes contact material and move it through the feeder, rotary valve feeders may damage or degrade fragile materials. Thus, these types of feeders are best used in applications involving non-fragile materials and products. In addition, while rotary valve feeders can achieve consistent feed rates, the rotating vane design can result in some pulsing as material is fed through the feeder into the conveyor.
Selecting and recommending feeders for bucket elevators is an important aspect of the application review process at UniTrak. In every case, we want to ensure that the bucket elevator is consistently and reliably fed, with no damage to the product, the environment, or operator health and safety. If you would like to know more about feeders for bucket elevators, please contact our sales department.