For registration information on these short courses (1, 2, 3 hours), which are primarily offered through industry conferences, please use the appropriate sponsor links on our Dates page. If you have additional questions, please contact Eric Maynard, senior project engineer/education coordinator, at (978) 649-3300 or courses08@jenike.com.

Handling or processing powders and bulk solids is fraught with problems, whether you are dealing with chemicals, plastics, pharmaceuticals, foods, metals, cement, or a myriad of other materials. You can pay dearly in downtime, lost or out-of-spec. product, decreased productivity, and start-up delays. Most solids flow problems occur because of the usual methods of selecting standard equipment with little or no consideration to the particular material or operating environment.

In this session, attendees will learn:

• causes of common flow problems
• using the right flow pattern to eliminate flow problems
• how to measure bulk solids flow properties
• how to design a hopper to prevent arching and ratholing
• how to select the hopper angle and material of construction
• consideration of other bin components, such as feeders.

The recently issued FDA draft guidance for enhanced product sampling was based on recommendations from the Product Quality Research Institute's (PQRI) Blend Uniformity Working Group (BUWG) as a means of more reasonably determining batch uniformity, and in particular to eliminate the need for routine blend sampling to support this same goal. Although the difficulties and expense of added blend sampling can now be avoided, it has also been recognized that the new approach is likely to reveal formulation and processing problems that might not have otherwise been found or understood with the previous testing requirements. To aid in the diagnosis of some of these problems, and to understand the significance of trends that will be seen in the newly collected data, a troubleshooting guide was created and published in Pharmaceutical Technology, and is referred to by the guidance as a potential resource. This guide will serve as the starting point for this session, which will focus on particular aspects of solids processing which can lead to dose uniformity problems. In particular, this session will focus on:

• an understanding of what segregation mechanisms can occur with a powder blend, and how the flow sequence through handling equipment can impact the resulting uniformity
• what underlying flow problems can occur during powder handling and transfer, which can affect dose uniformity
• how to identify root causes for the behaviors observed
• the standard testing methods that are available to characterize a blend’s behavior with respect to these problems, and how the results can be used to modify equipment to solve or prevent uniformity problems

How to Prevent Silo Failures

Silos and bins fail with a frequency that is much higher than almost any other industrial equipment. Sometimes the failure only involves distortion or deformation which, while unsightly, does not pose a safety or operational hazard. In other cases, failure involves complete collapse of the structure with accompanying loss of use and even loss of life.

In this session, attendees will learn common causes of silo failures include shortcomings in design, construction, usage, and/or maintenance of the silo and auxiliary equipment. Each of these causes will be explored in detail along with numerous case histories involving structural failure.

This session is geared to engineers in design, construction, maintenance and/or operations who design, build, operate or maintain silos. Attendees will learn about common mistakes in silo design, construction, and use, lessons learned from silo failures, and limits of design.

Powder caking, whether of raw material in bags or drums, or during storage of in-process material, is a major cause of problems. Being able to predict the conditions under which caking occurs, as well as identifying the material properties that lead to caking is necessary for avoiding or solving this problem.

This session will discuss a novel approach that utilizes both micro and macro properties of powders to identify the causes of caking and develop solutions. Properties discussed will include particle surface composition and hardness, moisture sorption/desorption characteristics, particle strength and size distribution, a powder’s response to temperature and humidity cycling, and the change in shear strength as a function of time consolidation and environmental conditions.

Particle degradation, or attrition, can also be a major concern during the handling of friable bulk solids. Particle attrition can negatively impact product quality, performance, or induce bulk solids flow problems. Understanding the causes of particle attrition, as well as common solutions which can be employed to minimize, if not eliminate this problem, will be covered in this session.

Chutes are used to direct the flow of bulk solids, e.g., from one conveyor belt to another. Unfortunately chutes all too often fail to perform reliably. Such failures can be costly, particularly where large tonnages of bulk materials are handled, such as in most mining and quarrying applications and ship and railcar loading and unloading facilities. This topic is important to industry because chute design principles are available to minimize, if not eliminate chute problems.

What will be covered:

• The difference between a chute and a hopper
• Typical chute flow problems
• Preventing chute pluggages
• Calculating cross sectional area to prevent pluggages
• Controlling the stream of particles
• Minimizing abrasive wear of the chute surface
• Controlling dust generation
• Minimizing particle attrition

Poor blend uniformity or content uniformity results may arise due to a number of factors. Complicating the interpretation of the results is the multi-disciplined nature of the problem: the physical behavior of flow of materials within a blender or bin; the errors introduced during sample collection, splitting, and handling; the possibility of analytical errors; variations in sample weights; physical losses of components during manufacturing; as well as the irreducible random behavior of particulate systems. This session gives an overview of the problems encountered with product (blend) uniformity analysis and covers:

• What the blend or dosage data may look like
• What the data is trying to tell you
• Root causes for the behaviors observed
• What to do next to confirm the root cause
• Possible solutions to the problems at hand

Although this session focuses on case histories in the pharmaceutical industry, the troubleshooting techniques can be applied to most, if not all, industrial blending applications.

Feeders are used to control the rate of material discharge from a bin, hopper, silo, or bunker outlet. Unfortunately, the mechanisms governing operation of feeders under bin outlets are not well understood in the bulk solids handling industry. As a result, many existing screw and belt feeders, as well as myriad other types of feeders, do not operate properly. This often leads to excessive power consumption, abrasive wear, particle attrition and, even worse, unreliable material flow. This topic is important to industry because methods are available to minimize, if not eliminate, process irregularities caused by improper design of volumetric and gravimetric feeders.

What will be covered:

• Advantages and disadvantages of various types of bin flow patterns
• Difference between a feeder and a conveyor
• Importance of making feeder design compatible with bin design
• Design techniques for screw feeders under elongated outlets
• Single vs. multiple screws
• U-trough vs. V-trough
• Screws used for sealing against gas pressure gradients
• Design techniques for belt feeders under elongated outlets
• Comparison of screw, belt, and rotary valve feeders
• Limitations on use of vibrating pan feeders
• Feeders for special applications
• When to use a gravimetric feeder
• Comparison of various types of gravimetric feeders

Obtaining a uniform blend of dry bulk solids is a problem faced daily by engineers and operators in industries as varied as pharmaceuticals, foods, plastics, and battery production. Typically, selection of an industrial blender is not made based on scientific principles, rather, a blender is often chosen based on other factors, such as, equipment cost, relationship with a blending equipment supplier, or use of a previous model. Although there are no first-principles mathematical solutions for selecting a blender, proven, practical guidelines do exist which aid in the process of selecting a blender vs. using a costly and time consuming trial-and-error approach.

In this session, attendees will learn:

• the three mechanisms of blending
• common types of blenders used in industry
• advantages and disadvantages for each blender
• continuous vs. batch blenders
• scale-up techniques for batch tumble blenders
• flow patterns within a bin or blender
• blender sampling techniques.

Two phase (solid/gas) interactions must be considered when analyzing the flow behavior of fine powders in bins, hoppers, and processing vessels. Flooding [524K QuickTime video] (uncontrolled flow) or limiting flow rates can occur at the outlet of a bin or hopper. Processing vessels used to purge or condition bulk solids may exhibit nonuniform solids flow and gas distribution. This topic is important to industry because fine powder flow problems can usually be minimized, if not eliminated, by using specialized design techniques.

What will be covered:

• Typical fine powder flow problems
• Flow patterns and their effects on flow problems
• Three modes of fine powder flow in mass flow bins and hoppers
• Limiting flow rates through hopper outlets
• Effects of outlet size and head of material
• Air permeation systems used to increase flow rates
• Design considerations for purge and conditioning vessels
• When fluidized handling should be considered
• Fluidization options

The following topics will be covered if time permits

• Fine powder segregation [220K QuickTime video] mechanisms
• Overcoming arching by use of gas pressure gradients (e.g. air blasters)
• Unsteady flow phenomena such as deaeration

Obtaining a uniform blend of dry bulk solids is a problem faced daily by engineers and operators in industries as varied as pharmaceuticals, foods, plastics, and battery production. Even if a "good" blend is achieved, the next problem is how to maintain that blend through downstream equipment. Poor blending or the inability to maintain a blend, i.e., segregation [220K QuickTime video], at the point where it is needed is always costly in terms of rejected material, extra blending time, and defective end products. This topic is important to industry because once the mechanisms of blending and segregation are understood they can be used to analyze particle segregation problems and to determine ways to eliminate such problems.

What will be covered:

• Analysis of blend uniformity
• Sample collection, splitting, and analysis
• Solids flow problems: (a) no flow, (b) segregation
• Flow patterns within a bin or blender
• Effects of bin and blender design on flow patterns
• Common mechanisms of particle segregation
• Methods to quantify segregation tendencies
• How flow patterns affect segregation
• How to modify/design solids handling equipment to minimize segregation
• Blending mechanisms
• Types of blenders

Free-flowing granules, such as, pebbles used on roofing shingles or ground coffee, can be highly susceptible to particle separation, or segregation. Even if a “good” blend is achieved from an industrial blending process, the next challenge is how to maintain that blend through the downstream handling equipment. Poor blending, or the inability of maintaining a blend (i.e., segregation) at the point where it is needed, is always costly in terms of rejected material, extra blending time, and defective end products. This topic is important to industry because once granule segregation is understood, it can be used to analyze problems and determine cost-effective solutions to help minimize or eliminate segregation.

In this session, attendees will learn:

• the common mechanisms of segregation with granules (e.g., sifting, sliding on a surface)
• how flow patterns through a bin or blender affect segregation
• methods to quantify segregation tendencies
• case studies of granule segregation problems
• how to design/modify bulk solids handling equipment to minimize segregation.

Understanding fine powder segregation behavior is critical to preventing and solving blend and product uniformity problems. Different product formulations may exhibit different segregation tendencies due to differences in physical properties. However, the equipment configuration also plays a significant role in determining which segregation mechanisms will be active (e.g., dusting and fluidization segregation), and to what extent segregation occurs. Factors such as cohesiveness and wall friction will influence the flow sequence and how segregated zones are recovered and fed to downstream equipment.

In this session, attendees will learn:

• primary segregation mechanisms for fine powders and their blends
• segregation test methods
• how particle size can affect segregation tendencies and the random distribution of particles
• material flow patterns through the system and why they occur
• the effect of flow pattern on blend and product uniformity
• case studies of fine powder segregation problems
• preventing segregation by way of proper equipment design and selection.