Solids Handling Technologies, Inc.

Lecture 1: Flow Problems, Their Effects, and Flow Patterns

During lecture 1, Joe Marinelli of Solids Handling Technologies will guide you through several common bulk solids flow issues with solutions based on Dr. Andrew Jenike’s renowned work, “Storage and Flow of Solids, Bulletin No. 123”.

Topics covered in this lecture include flow problems due to arching and ratholing, flooding issues, limiting discharge rates and segregation problems.  These issues can have devastating results such as limiting live storage, caking and spoilage, and even potential structural problems with your silo.

Solutions to the above problems are dependent on the flow pattern that develops in your silo or storage vessel.  Joe discusses poor flow such as exhibited by “funnel flow” where significant product can remain stagnant and reliable flow using “mass flow” where all the product moves upon discharge.  As well, a combination flow pattern called “expanded flow” is discussed.

Lecture 2: Design Principles for Reliable Flow

This lecture will further develop the topics discussed during lecture 1. The design principles required to ensure reliable flow from your bins, hoppers, and feeders will be covered extensively.

Topics covered in this lecture include the ASTM standard for measuring bulk solids flow properties, using the Jenike Shear Tester.  This device allows the user to determine material wall friction properties as well as its cohesive strength.  Wall friction tests yielding the angle of wall friction, leads to determination of hopper angles required to ensure flow along the walls, which is mass flow.

Additionally, measurement of a bulk solid’s cohesive strength is illustrated.  Once your material’s cohesive strength is determined, you will learn how to calculate hopper opening sizes required to prevent arching.

Lecture 3: Feeders

This lecture will describe and discuss the effectiveness of both volumetric and gravimetric feeding devices.  The topics covered in this lecture include volumetric feeders which discharge a volume of material per unit time.  The key to reliable feeder design is to make sure that the feeder is capable of discharging your product uniformly over the entire outlet cross-sectional area.  The type volumetric feeders detailed are screws, belts, and rotary valves.  Additionally, louvered feeders and The Circle feeder are discussed.

The information regarding gravimetric feeders concentrates on systems required to provide weighments of product passing through the devices.  Weigh belt feeders are discussed along with what is considered the state of the art today, loss-in-weight feeders.  Gain-in-weight feeders which can be as simple as a container on a scale are described along with their limitations.

Lecture 4: Measuring Bulk Solids Flow Properties

In Lecture 4, Measuring Bulk Solids Flow Properties-Shear Testing, Variables that Affect Properties, we provide a detailed discussion of the preferred method to determine a bulk solids flow properties.

Topics covered in this lecture include a discussion of direct shear testers available to use with a concentration on the Jenike Shear Tester which is the ASTM standard in the US.  The test method is demonstrated by showing cohesive properties tests which allow you to predict your materials opening size to prevent arching and ratholing.  As well, wall friction tests are demonstrated using several wall surfaces, which lead to determining the hopper slope required to ensure flow along your hopper walls.

Additionally,  rotational testers such as Peschl and Freeman  along with annular testers such as Ring Shear Tester and Brookfield are  discussed.

We also discuss the variables that affect your material’s flow  properties, such as: moisture content, particle size, temperature,  relative humidity, and time of storage at rest.  These variables play a  major role in the flowability of a bulk solid.  Each of them is taken  into consideration when running shear tests on your product.

Lecture 5: Particle Segregation

Segregation of particles is a major problem in many industries such as pharmaceuticals, roofing shingles, and even batteries.  In Lecture 5, Particle Segregation-segregation mechanisms, solutions to common problems, we provide a detailed discussion of the mechanisms that cause segregation or separation of particles.  Additionally, solutions to common segregation problems are discussed.

Topics covered in this lecture include sifting and fluidization segregation along with segregation effects of flow through chutes and transfer points.  Several examples of each mechanism are discussed in detail with examples of common problems and solutions to those problems.

We describe sampling techniques to be aware of and their affect on segregation.  We also discuss several approaches to solving typical segregation problems such as, changing your process, changing your material or changing your equipment to minimize the effects of segregation.  A unique approach to solving segregation problems known as a “cone-in-cone” design is described.

Lecture 6: Flow Aids

In Lecture 6, Flow Aid Devices, Joe Marinelli of Solids Handling Technologies explores the area of flow aid devices that can be used to enhance or encourage flow from bins and hoppers.  Although our lecture series concentrates on primarily using gravity to pull material from bins and hoppers, sometimes gravity needs help.  Flow aids are intended to assist gravity by overcoming arching and ratholing problems.

Topics covered in this lecture include vibratory type devices such as bin dischargers and vibrators along with those that agitate product.  As well, forced extraction equipment such as silo bottom reclaimers and fluidization is discussed along with the availability of flow aid additives and chemicals.

Joe describes the equipment available within each of these categories and provides insight as to whether the devices discussed are practical, reliable and more importantly effective.  This lecture will ensure that if flow aids are warranted, you will make the correct decision in purchasing and installing them.

Lecture 7: Retrofits to Existing Systems

In Lecture 7, Retrofits to Existing Systems, Joe Marinelli of Solids Handling Technologies discusses several possible retrofit solutions to common flow problems.  Joe will describe uses for liners such as TIVAR 88 and 2B stainless steel along with coatings such as electrostatic powder coatings and Plasite 7122 epoxy coating.

Geometry modifications are considered, such as wedge type hoppers, transition hoppers, splitters and chutes.  These modifications are practical and will resolve many flow issues

Joe  discusses inserts such as classical inverted, cone shaped inserts along  with a unique cone-in-cone design.  The cone-in-cone approach will  allow the user to: modify an existing funnel flow bin to flow in mass  flow, provide anti-segregating benefits along with blending  capabilities.

Lecture 8: Design Example

Joe Marinelli of Solids Handling Technologies takes you through a typical design example.  The example begins with an assignment you may receive to design a bin and feeder to reliably handle your product.

Joe discusses the actual data plots that would typically be generated during testing of your materials and their interpretation.  He uses the Jenike design approach to calculate opening sizes and hopper angles.

Joe  discusses minimum opening size calculations and hopper angles for mass  flow conical hoppers and wedge type hoppers.  He also describes funnel  flow bin designs requiring calculation of your material’s rathole  dimensions.  A design is ultimately created according to the data and  calculations made during the presentation.