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Volume 7, Issue 2                                                                                                            
In This Issue:

This issue will focus on “Particle Size and Shape and Their Impacts on Solid-Liquid Separation”    

Welcome to A&SoF. A&SoF is an e-newsletter, managed by BHS, with its sole purpose to enhance the filtration knowledge of the marketplace to solve actual plant problems.
This issue focuses on the challenges of particle size analysis both off-line and in-process and how the particle size and shape impacts the filtration system designed to handle the specific solids. Two articles, one from Mettler-Toledo and one from Micromeritics, discuss analytical approaches to particle analysis.  The follow-up to this is a BHS discussion of troubleshooting filtration systems and how focusing on the particle sizes can resolve a problem.      
As always, thanks again, to our readers, for your feedback and if you missed any issues, please click on the following link:  A&SoF to view them.   Our goal this year is a deeper dialog and engaging conversations with the many authors, bloggers, tweeters and experts from our industry.      


Barry A. Perlmutter 

Featured Problem Solving Technical Articles


Sleuthing in Solid-Liquid Separation

Cloud Seeding, GE Research & Kurt Vonnegut

Yes, these three topics are related.  The blog starts with cloud seeding in India to help alleviate drought conditions, continues with GE Research in New York, takes a path to the Albany State University and then ends up at the Cat’s Cradle. 
The most recent blog talks about “Building Your Technical Library” and why this is not so common as mostly all information that engineers need is on-line.  Let me know what’s in your library.  

Read the Blog



By:  Mettler-Toledo, Columbia, Maryland

The article discusses how to characterize particle properties effectively, especially size and count which allows processes and processing problems to be solved.  Historically, engineers have relied on off-line particle size analyzers such as laser diffraction or sieving to perform this type of characterization.  In recent years, however, newer technologies have emerged which describe particle size and count in real time as they naturally exist in the slurry.  In-Process measurement of particles can reduce the error associated with off-line sampling and can provide continuous information about how particles behave under changing process conditions.  This allows engineers to better understand and optimize difficult processes using evidence-based methods.
Read More….  


By Micromeritics, Norcross, GA

This Application Note discusses different measurement techniques which report an “equivalent spherical diameter” and how each technique can produce a different particle size distribution when particles are non-spherical.  Understanding what each particle size technique actually measures, how it performs the measurement and how it transforms the quantity measured into equivalent spherical diameters are crucial when selecting the most appropriate particle sizing technique for the application.  Read more … 


In Chapter 6, of the “Guide to Solid-Liquid Filtration”, there are several troubleshooting examples where the particle size distribution (PSD) changed from the pilot scale to production scale as well as even during the production operation. 
In a specialty chemical application for a continuous rotary pressure filter, testing showed a dual distribution in the PSD of the product.  The sampling was conducted on the batch reactor.  The engineering team, as part of the project to install a continuous process, converted the batch reactor to a continuous reactor and assuming the same PSD.  Unfortunately, the continuous reactor produced a completely different PSD which then required changes to the filter media.
In a clarification application with candle filters, the system was running successfully for over one-year.  Inexplicitly, the performance changed drastically and the filter media began plugging very quickly during the cycle.  The process engineers narrowed down the changes to the chemical supplier of the flocculants and coagulants.  The resulting testing showed that the chemical change caused the larger particles to settle out quickly and therefore only the smaller particles reached the filtration system.  The client and the chemical company reduced the amount of chemicals used (better for the client and not so good for the chemical supplier) which produced a smooth PSD and better filtration rates. 
Once again, we see the systems approach to process filtration and “not jumping to conclusions” as the guiding principle.  Read more either by downloading the Guide or contact BHS for a free copy.


Contact BHS for your process development needs via lab and pilot-plant testing and “lunch & learn” filtration brainstorming sessions
C³ - Customer Contribution Corner
BHS News & Updates:

BHS vacuum belt filter, 6.5 m2, new and in–stock….. and ready for immediate delivery.


  • All wetted parts in polypropylene
  • Filtration zones with oscillating feed
  • Cake washing zones
  • Steaming zone
  • Pressing zone
  • Drying zones
  • Liquid ring vacuum pump in stainless steel
  • Filtrate receivers and pumps
  • PLC controls

Guide to Solid-Liquid Filtration by Barry A. Perlmutter.
This book is part of the series of Practical Guides of Chemical Engineering published by Elsevier, Oxford, UK.

Petroleum Technology Quarterly (PTQ), 2Q Issue
BHS technology article “Solid-Liquid Separation technology for removing contaminant fines from water scrubbing, clarifier effluents and grey water.” 

PharmaChem, 2Q Issue
BHS technology article “Thin-Cake Filtration for Full Containment of Air Sensitive and Chemicals for Pharma Production.

2016 FILTECH, 11 - 13 October, Cologne, Germany
BHS will be in booth C12 in Hall 11.1 and will be presenting our solid-liquid filtration technologies with over 60 years of experience. 

BHS New On-Site Service Contract Program.
Please contact BHS for information on our new program including spare parts discounts. 

For Our Existing Clients: Please Remember to Contact BHS for Your On-Site Service

"Lunch & Learn Filtration Seminars": BHS is organizing technical seminars focusing on the principles of filtration with application specific information. Contact BHS for details and scheduling.