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JUNE 2002
From Johanson Innovations, Inc. the exclusive source for Indicizer technology.
In this issue we will focus on the Flow Rate Index (FRI). It is the maximum flow rate expected after deaeration of a powder in a bin with a one foot outlet measured in lbs/min. FRI is a very effective tool in predicting and eliminating problems relating to segregation, tablet capping, and flowability. All papers referenced can be downloaded in PDF format and are located at the bottom of this page.
Also in this issue is the latest paper written by Dr. Jerry R. Johanson. This paper explains how to use material flow properties to solve flow problems and make educated equipment selection. You can download this paper at the bottom of this page.
SEGREGATION
The five most common types of segregation are sifting, angle of repose, fluidization, air current and chute. Because segregation is directly related to differences in particle sizes, FRI can be a very helpful to in assessing the potential for these types of segregation. This is because FRI is a direct measurement of mean particle size of the sample.
Lets look at angle of repose segregation where larger particles tend to accumulate at the lower edges of a pile and fines concentrate at the center of the pile. Using the Flow Rate Indicizer you can test both sections and determine FRI. The FRI from the lower edges will be higher than the sample taken from the center. This will give you a range of particle sizes found in the material. From this you can now run an FRI from a sample taken at any point in your process and determine if there is segregation. If the FRI is toward the upper range you have a concentration of large particles and if it is toward the lower range then there is a concentration of fines. Particle size analysis will also determine a range of particle sizes but only FRI can determine where segregation is happening in your system in a 4 minute test.
For more details regarding segregation please refer to pages 14-17 in the Indicizer Application Guide and to Predicting Segregation of Bimodal Particles.
INDICIZER ADVISOR JUNE 2002
Related Articles
This presentation shows how to use basic properties and the indices derived from them to solve flow problems in bins, hoppers, stockpiles and feeders and how to use these valuable tools to select and size equipment for trouble free plant operation. Practical guidelines and suggestions are provided for avoiding solids handling problems in bins and stockpiles. Dr. Jerry R. Johanson. June 2002.
How a powder's physical functionality often determines the success or failure of pharmaceutical processing. Dr. Jerry R. Johanson, Innovations in Pharmaceutical Technology, second edition, 1999, pp. 136-146.
This article considers a bimodal mixture, relating each component's properties to its segregation tendencies, when caused by the five most frequently encountered segregation mechanisms. Dr. Jerry R. Johanson.
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