6 KEY DESIGN DECISIONS
Good bin and feeder design for a difficult flowing material can be reduced to a physics problem. On one hand you have gravity – the primary force available to empty your storage bin, and on the other hand you have the shear strength of the material, which allows it to form a bridge or stable rat-hole in your storage bin or pile. Ultimately, good design is about making deliberate decision on the geometry of the storage bin and behaviour of the Feeder to ensure that gravity will always be sufficient to overcome the shear strength of the bulk solid. At Kamengo we believe that good design centres on six key design decisions.
MATERIAL FLOW TESTING
Designing for a difficult flowing material starts with knowing the material. However, when it comes to bulk solids, looks can be deceiving. A material’s angle of repose is largely unrelated to how it will behave in a storage bin. In contrast, knowing the rate at which a bulk solid gains shear strength as it is compacted tells you a lot about the minimum discharge opening needed to ensure gravity will be sufficient to prevent arching at the discharge outlet. Kamengo Labs has a full suite of bench-scale equipment for determining the flow properties of your bulk solid, including proprietary equipment for characterizing large particle and non-standard bulk solids. We are able to measure how much strength a material gains when it is compacted as well as how it interacts with different bin wall materials, We then use this information to design custom storage bins and hoppers your material will reliably discharge from. Kamengo Labs also has at-scale test equipment which it uses to confirm equipment designs.
THE KEY FEATURES OF THE KAMENGO FEEDER
Designing for a difficult flowing material is a challenging exercise, in part because the theory often calls for the material to be discharged via a wide fully effective long, slotted opening. This is very challenging to do with conventional technologies, but very easy to do with the Kamengo Feeder. The Kamengo Feeder can be made as wide as needed and as long as desired. Further, it is a proven solution for handling difficult flowing materials in mass flow or funnel flow as well as tall and long storage and feed applications.
THE KAMENGO-U LEARNING MODULES
Though bulk solids handling is found everywhere, the theory that governs good bin and feeder design is only taught at the graduate level at a handful of universities. Further, the theory is often presented in a complex language, making it intimidating and hard to understand. KamengoU was established to present the theories of good bin and feeder design in plain English to designers and engineers. KamengoU is a library of videos and whitepapers organized into a series of modules of graduated learning.
Since installing our first feeder in 1988, Kamengo has established a design practice capable of tackling complex projects, including retrofits of storage and feed arrangements that are suffering from chronic plugging. Kamengo has the engineering capability to deliver complete packages of materials handling equipment including storage bins, feeders, chutes, structural work, and conveyors. We have delivered solutions for the mining, pulp and paper, cement, gypsum board, marine, and agricultural industries.
Kamengo was born from a research team that spent 15 years exploring the question of why bins plug. The starting point for the team’s research was the early work conducted by Dr. Jenike at the University of Utah in the 1950s and 60s. Jenike developed the theory for translating a bulk solid’s flow properties into a bin design that can self-empty with gravity.
The Kamengo research team was interested in knowing whether Jenike’s theories applied to large particle materials as well as wet, cohesive materials like wood waste and gypsum. Using a full-size storage bin, where they could change the angles of the bin walls, change the bin discharge opening and change the bin wall lining, the Kamengo research team tested a wide range of bulk solids. The research showed that Jenike’s theories apply to a wide range of bulk solids, and can reliably predict the minimum geometry required to discharge a bulk solid with only gravity. However, the research also showed that good bin design was only half the solution.
The Kamengo research team discovered that the behaviour of the Feeder was a major contributor to bin plugging. First, conventional feeders have a propensity to compact material as they shear material from a storage bin. Second, conventional feeders have a tendency to withdraw material preferentially from the rear of the storage bin. This uneven discharge promotes a first-in, last-out discharge, which can be very problematic when handling a difficult flowing material. The limited area of withdrawal also promotes rat-holing and bridging. The shearing of material, along with uneven discharge, often results in a bin that refuses to empty via the conventional feeder even if the bin was properly designed.
Observing the shortcomings of conventional feeders, the Kamengo team asked themselves whether they could rethink the feeder. This led to the development of the Kamengo Feeder.
In 1988, Kamengo installed its first Kamengo Feeder. Since then, the company has developed into a design practice that specializes in the design of storage bins and feeders for handling difficult flowing bulk materials. The company has tackled complex projects, including retrofits of storage and feed systems suffering from chronic plugging. Kamengo has installed over 100 storage and feed systems, serving multiple industries and handling a variety of large particle, cohesive and fine bulk solids.