SHORT PRESENTATION
OUTLINES
COURSE AVAILABILITY
For registration information on these short courses (1, 2, 3 hours), which are offered through industry conferences, please use the appropriate sponsor links. If you have additional questions, please contact Eric Maynard, Director of Education, at (978) 649-3300 or courses12@jenike.com.
PROVEN
TECHNIQUES FOR SOLVING SOLIDS FLOW PROBLEMS IN BINS AND HOPPERS
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.
IDENTIFYING
AND SOLVING DOSE UNIFORMITY PROBLEMS
The recently issued FDA draft guidance for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.
HOW TO PREVENT CAKING OF BULK SOLIDS
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.
HOW
TO PREVENT ATTRITION OF BULK SOLIDS
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.
DESIGN OF TRANSFER
CHUTES TO MINIMIZE BUILDUP, ABRASIVE WEAR, AND DUST GENERATION
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
TROUBLESHOOTING
BLEND AND PRODUCT UNIFORMITY PROBLEMS
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.
HOW TO SELECT
OR TROUBLESHOOT VOLUMETRIC AND GRAVIMETRIC FEEDERS TO ENSURE
RELIABLE FLOW
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
HOW TO SELECT
A BLENDER FOR YOUR INDUSTRIAL MIXING APPLICATION
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.
FINE
POWDERS: RELIABLY HANDLING BULK SOLIDS THAT CAN BEHAVE LIKE
FLUIDS
Two phase (solid/gas) interactions must be
considered when analyzing the flow behavior of fine powders in bins,
hoppers, and processing vessels. Flooding (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 mechanisms
- Overcoming arching by use of gas pressure gradients (e.g. air
blasters)
- Unsteady flow phenomena such as
deaeration
BLENDING
AND SEGREGATION AND THEIR EFFECTS ON PRODUCT QUALITY
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, 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
UNDERSTANDING AND PREVENTING
SEGREGATION OF GRANULES
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
AND PREVENTING SEGREGATION OF FINE POWDERS AND THEIR BLENDS
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.
