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PBE News
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In this issue...

Ask an Expert: Reducing elbow wear in pneumatic conveying
More Questions and Answers
Feature: Using crushers for coarse grinding
Read It Here First: Gravimetric feeder controls
Industry News

DECEMBER 7, 2011

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Agglomeration
Equipment

Franklin Miller
Hosokawa Micron Powder Systems

Airlocks, Blowers & Related Equipment
FLSmidth
K-Tron
Nol-Tec
Smoot
Vortex Valves

Bagging Equipment
Chantland
K-Tron
Taylor Products

Bin Activators, Vibrators & Material Flow Aids
Acrison
Eriez
K-Tron
Monitor Technologies LLC
Nol-Tec
Smoot
Vac-U-Max

Bin Level Indicators
K-Tron
Monitor Technologies LLC
Vac-U-Max

Bulk Bag Fillers & Dischargers
Acrison
APEC
Chantland
Flexicon
K-Tron
Nol-Tec
Schenck AccuRate
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Tecweigh
Vac-U-Max

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Hosokawa Micron Powder Systems
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Smoot

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Camfil Farr APC
K-Tron
Monitor Technologies LLC
Nol-Tec
Smoot
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Acrison
Chantland
Eriez
FLSmidth
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Jenike & Johanson
K-Tron
Nol-Tec
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Smoot
Taylor Products
Tecweigh
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Acrison
APEC
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Linings (Abrasion Resistant)
Hosokawa Micron Powder Systems
Vortex Valves

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Acrison
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FLSmidth
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Jenike & Johanson
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Smoot
Taylor Products
Tecweigh
Vac-U-Max
Vortex Valves

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Acrison
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Eriez
Flexicon
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KWS Manufacturing Co Ltd
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Eriez

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Acrison
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Nol-Tec

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Hosokawa Micron Powder Systems

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Smoot
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Acrison
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Smoot
Taylor Products
Tecweigh
Vac-U-Max

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Acrison
APEC
Chantland
Flexicon
Franklin Miller
Jenike & Johanson
K-Tron
Meridian Manufacturing
Tecweigh
Vortex Valves


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Schenck Accurate Vortex Valves Noltec Sentry
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Vacumax

Ask an Expert

Reducing elbow wear in pneumatic conveying

Q: My pneumatic conveying system, which transports an abrasive mineral, suffers from extreme bend wear problems. We're never done welding up the elbows—some fail every week or two—and the worst always seem to be the ones at line's end and the silo's top, which present a safety hazard to access. Would it help us to change to a longer bend radius?

Mike Bradley, of The Wolfson Centre for Bulk Solids Handling Technology, says: Anywhere that you have hard, angular particles, there's potential for them to cause bend wear due to the particles' impact on the bend’s inner radius. It's tempting to think that a longer bend radius will allow the particles to follow the flow more easily and will reduce collisions with the wall. However, this is a fallacy—even in a very long radius bend, the particles still travel in virtually a straight line from the inlet to the impact point. A longer radius bend will give some extension to wear life because the impact zone is longer in respect to the arc’s length. Tests in our laboratory have shown roughly a doubling in bend life when the ratio of radius to diameter increases from 6 to 12. However, if you have a serious wear problem, you need much more than a doubling of bend life!

CONTINUED...

Mike Bradley is the director of The Wolfson Centre for Bulk Solids Handling Technology at the University of Greenwich.

Think you’ve got what it takes to be the Expert?
We’re looking for guest contributors for the Ask the Expert section—email awiebe@cscpub.com for more info.

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Acrison

More Questions and Answers

Q: Our current dilute-phase pneumatic conveying system is degrading the particles in the friable agglomerated product we’re handling and thus destroying our desired particle size distribution. Is there a way to reduce this product attrition?

read the answer

Send Us Your Questions!

To send us your questions email awiebe@cscpub.com
 
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Hammertek

Feature

Using crushers for coarse grinding
Rob Voorhees, Hosokawa Micron Powder Systemsphoto

Size reduction equipment for dry bulk materials can yield coarse, medium, fine, or ultrafine particles. In coarse grinding, the particles produced are usually in the range of 150 microns (0.75 millimeter) to 0.5 inch (12.70 millimeters) or larger.

Coarse grinding mills for dry bulk materials operate based on one or more of four size reduction principles: shearing, attrition, compression, and impact. In shearing, a particle is cut or cleaved in two with a sharp blade. In attrition (also called autogenous grinding), a rubbing action in opposite parallel planes between two particles or between a particle and a surface abrades each. In compression, a particle is pressed between two solid surfaces to reduce it. In impact, a solid object moving at high velocity strikes a particle and breaks it. This article will discuss crushers, which employ the final kind of grinding (impact) to achieve the finest possible particles, especially with hard crystalline and amorphous particles.

Continued ...  
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K-tron

Read It Here First:

Gravimetric feeder controls
Sharon Nowak, K-Tron
photo

Gravimetric feeders are commonly used to feed bulk solids in the chemical, pharmaceutical, food, and plastics industries. Unlike a volumetric feeder (such as a screw feeder), which feeds material by volume, a gravimetric feeder feeds material by weight. In both batch and continuous operations, the gravimetric feeder uses a load cell measurement to feed material into a process at a constant weight per unit of time. Integrating the load cell measurement with the feeder's control algorithms is critical to the feeder's performance.

Today most bulk solids gravimetric feeders are highly automated, and their combination of advanced load cells and control algorithms achieves feeding accuracies as high as ±0.25 percent of the desired feedrate, based on load cell resolutions as high as 1 in 4,000,000. Today's control technologies allow gravimetric feeders to be customized to deliver high feedrate accuracy even in tough plant environments.

Simply put, gravimetric feeder controllers automate feeding by comparing key measured variables with their required setpoints. These comparisons generate an output signal that the controller uses to adjust a feeder control parameter, such as the feeding device's motor speed.

The gravimetric feeder measures the actual material discharge rate by taking consecutive weight samples at short time intervals (for example, 1 second, 5 seconds, or 15 seconds) during feeder operation. To control the feedrate, the controller must then compare the actual discharge rate to the feedrate setpoint and calculate and apply any required corrective motor-speed adjustment for the feeding device. The controller also evaluates weight noise (ambient vibration) and adjusts its weight filter (software that filters weight noise from the weight signal) and control parameters accordingly.

To learn more about advanced control technologies and how the interact with gravimetric feeders, you can read "Gravimetric feeders: Advanced control technologies for precise feeding" by Sharon Nowak, K-Tron, in the December issue of Powder and Bulk Engineering.

To read it today, click here.

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Jenike & Johanson

Industry News

Nanotech conference calls for papers

The Nanotech Conference & Expo 2012, part of TechConnect World, will be held June 18-21 in Santa Clara, California. The conference team is calling for research papers for both oral and poster presentations, with an early bird deadline of December 16. Click here for more information and to submit your abstract.

USM to offer degree in polymer science and engineering

The University of Southern Mississippi's School of Polymers and High Performance Materials has gained approval from the State Institutions of Higher Learning to offer an undergraduate degree in polymer science and engineering. The degree, which will be the first of its kind in Mississippi, will focus on education and research in the structure and processing of polymeric materials and how these relate to properties and performance. www.usm.edu


photo
PBE 25th Anniversary issue

Powder and Bulk Engineering will celebrate its 25th anniversary this January. Be sure to watch for our special anniversary issue in your mailbox!

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Franklin MIller

Supplier News

FLSmidth to supply mineral plant in Mexico

FLSmidth has been awarded a contract by Minera Peñasquito, which is owned by Goldcorp, to supply a complete semi-mobile sizer station for minerals processing in the state of Zacatecas in Mexico. FLSmidth will design and supply the semi-mobile station with a capacity of more than 13,500 tons per hour, making it the largest sizer station in the world. For more info, visit www.flsmidth.com.

Editor's note: Send your news items to awiebe@cscpub.com.  

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Flexicon

Events

NFPA to hold safety conference

The National Fire Protection Association (NFPA) will hold the Fire & Life Safety Conference on December 12-14 at the Hilton in the Walt Disney World Resort in Orlando, Florida. The conference will feature more than 60 educational sessions in four targeted tracks. Visit the conference info page for more information.

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Nerak Systems

Continuing Education

Webinar to discuss baghouse design and operation

PBE will host the webinar “Reliable Baghouse Operation” at noon EST on Tuesday, December 13. Gary Johnson will discuss how to correctly design and operate a baghouse to achieve reliable performance. Click here for more info and to register.
 

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PBE 2012 Southeast Conference & Exhibition

 
Copyright 2011, CSC Publishing Inc. All rights reserved.
PBE-News provides information updates about the dry bulk materials processing and handling industry twice a month. The opt-out link below will allow you to opt out of future PBE-News. This will in no way affect our contact methods regarding your subscription or communication. Thank you.
 

PBE-News Editor
Austin Wiebe
awiebe@cscpub.com

 

PBE-News Designer
Kelly Weyandt
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