DeDuster® Anthology –

The Complete Guide

DeDuster® Anthology –
The Complete Guide

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 Mobile DeDuster® in a silofarm
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 DeDuster® Anthology –
The Complete Guide

Contents

Page

Following Nature’s Lead 4

Where Do Fines Come From and Why is Cleaning So Important? 5
The Pelletron DeDuster® – The Ultimate Cleaning Technology 6
DeDuster® Applications for the Plastics Processing Industry 7
DeDuster® Applications for the Plastics Manufacturing and Compounding Industry 8

DeDuster® Applications for Other Industries. How Versatile is the DeDuster®? 9

Systems Configurations 10
Selecting the Right Dedusting System 12
Dedusting Test Facilities 13
Research & Development 13

DeDuster® Product Line 14

Pelletron DeDuster® Systems are Installed All Over the World 16

3
Following Nature’s Lead

Purity of material was the driving force behind the development of separation
technologies. It began thousands of years ago with the need to clean grain,
corn, rice and other foods, a task that was accomplished with the aid of a simple
stream of air. Over the centuries, the desire for efficiency resulted in new
­inventions all designed to improve the cleaning and separation processes.
Our modern day machine cleaning technology is based on this same concept
of separation with air.

Product inlet

Air and
fines outlet

In order to build an understanding of the technology of

Air inlet
cleaning or “dedusting” materials, let us first take a look at
history. After the most basic cleaning method of simply tossing Product outlet
the material into the air and letting air and gravity do the (heavy materials)
work, the need to improve efficiency resulted in other innovations.
The “scalperator” was a separation machine that removed Scalperator
hulls from grains.

Later, the “aspirator” was used. Its cleaning principle is based

on air blowing perpendicular to the material flow. This was an Air and Product inlet
fines out
efficiency improvement, one that is still useful in industries
with lower cleaning efficiency requirements like agriculture,
among others.
Air in

The requirement for higher cleaning efficiency continued and,

in the 1970s and 1980s, the plastics industry began to drive
demand. The need for better quality resulted in the develop- Air in
ment of the “elutriator.” This technology was focused on the
cleaning of pellets at the end of a dilute phase conveying line.
Because of its working principle, an elutriator was typically
Air in
installed on top of a silo or before a silo farm, where the
­distribution of pellets to the storage silos is done after
cleaning. Because its principal of cleaning is based on coun-
terflow, the elutriator does not remove long streamers, also Air in

called “angel hair”, so it was often combined with a drum sieve.

The graphics on the next page illustrate the counterflow
Product outlet
­principle and a typical elutriator installation at a silo farm. (heavy materials)

Aspirator

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 DeDuster® Anthology –
The Complete Guide

Inlet for pellets

and conveying air

Elutriator
System

Dusty air outlet

Pellet acceleration

Cleaning zone by
counterflow air
System with Elutriator
Detail
Cleaning air inlet

Many more separation and cleaning machines were marketed

to address specific application requirements. There were
­separators with bottom entry and separators with rotating discs,
among others. As efficiency demands increased, the dedusting
technology emerged as a solution that provided superior results
when cleaning all kinds of bulk solid materials. As technology
evolved further, the Pelletron DeDuster® emerged as the most
Product outlet
efficient way to remove all kinds of dust, streamers and other Rotary Valve
contaminants. For a better understanding of fines creation
and modern fines removal, let us take a closer look.
Elutriator

Where Do Fines Come From and

Why Is Cleaning So Important?

Some dust and contaminants occur naturally in products like

minerals, food, tablets and other bulk solids, while others are
caused by the way the products are handled. Impurities in
plastic pellets, both fines (dust) and angel hair (streamers),
are generated by the friction in conveying lines. Dilute phase
systems create large amounts of dust and streamers; the
­higher the velocity, the larger the amount of impurities. Pipe
elbows also cause friction and result in the creation of more
dust and streamers. The high pressure in dense phase, or slow
motion systems, creates very fine dust due to wall friction and
friction between pellets. Temperature, pellet shape and product
characteristics can also contribute to the creation of dust.

Cleaning bulk solids is important for a number of reasons.

Food and pharmaceutical bulk solids are cleaned for hygienic
reasons and to improve the quality of the finished, packaged
product. Minerals are cleaned primarily to avoid environmental
and health problems. The plastics industry cleans pellets to
improve the quality of both the pellets and the finished plastic
product.

5
The Pelletron DeDuster® –
The Ultimate Cleaning Technology
The Pelletron DeDuster® was developed as a result of
­demands for high quality standards in the plastics industry,
but the technology can be used for all kinds of granular
bulk materials. The list of requirements for a new, universal
dedusting machine was long:
Dusty product in

Remove dust and streamers with one machine

Separate and remove electro-statically charged dust particles
Fit on injection molding machines Dusty air out
Offer low construction height
Fit on top of extruders and under silos
Reduce remaining dust level after cleaning to <50PPM
Air in

To address this list of requirements, Pelletron developed a

Bypass air
cleaning machine that combines a variety of air wash principles,
plus the revolutionary electro-static flux field feature, and
built it with the lowest possible construction height. When Air in Air in
charged particles enter into the Magnetic Flux Field, the result­
ing “Lorentz Force” weakens the electro-static bond between
fine dust and plastic pellets. This weakening, in combination
Clean pellets out
with the air flow, allows the micro fine particles attracted to
the pellet surfaces to be removed.

The Pelletron DeDuster®

The specially designed slot and hole pattern in the air wash
deck creates a fluidization effect, another advantage of the
Pelletron DeDuster®. For removing large particles and streamers,
an adjustable Venturi Zone was designed. Adjustment of the
Venturi Zone width, in combination with the regulation of the
bypass airflow, allows a perfect separation of streamers from
good product. This special air wash effect also removes the
heavier particles such as paper, metal parts < 300 micron and
other contaminants. The airflow in the DeDuster® creates
­negative pressure at the DeDuster® outlet.

All DeDuster® systems are equipped with a window made of

either polycarbonate or glass. Optionally, a stainless steel
door with windows can be supplied for high temperature
­applications. The DeDuster® can also be operated in inert gas
environments such as N2-systems. In situations where a
­DeDuster® is installed before or after a conveying system, the P-Series DeDuster®, showing air wash deck
DeDuster® inlet or outlet needs to be separated by a rotary and Venturi Zone
valve.

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 DeDuster® Anthology –
The Complete Guide

DeDuster® Applications for

the Plastics Processing Industry
Production of high quality end products requires clean plastic
pellets. Dust and streamers in plastic pellets cause many
­problems for the plastics processing industry:

High “scrap” rates from fines burning in mold

Before After
Blurry surfaces resulting from vaporized dust particles
Weak spots in fibers
Flaws in wire insulation
Gels in films
Housekeeping problems caused by dust and streamers
Crusting of feed throat of screw
Reduced mold and screw life resulting from
carbonization of dust
Mold vents clogged by dust
Equipment and machines clogged by streamers
Dust accumulation on silo walls, roofs and hopper walls
Problems caused by dust

A DeDuster® can be installed directly on top of an injection

molding machine or on a dryer, depending on the process
­requirements. The standard installation is a closed loop
­configuration with a fan and a dust collector. The removed dust
is separated by the dust collector and dropped into a dust ­bucket,
and the cleaned air is returned to the DeDuster®. Special
­configurations for clean room applications are also available.

Regrind is also common in the plastics processing industry.

Regrind is very dusty and needs to be cleaned before it is
mixed with virgin pellets, before packaging into big bags or
re-pelletizing.
High quality end product

C-20 DeDuster®
installed on
injection molding
machine (IMM)

1. Untreated Product
2. Cleaned Product
3. Compressed Air Supply
4. Fresh Air Inlet (Filtered)
5. Dirty Air
6. Dust & Streamers
7. Outlet Air (Filtered)

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DeDuster® Applications for the
Plastics Manufacturing and Compounding Industry

Clean pellets, without dust or streamers, are the goal of every plastic manufacturing
company. The most effective use of a DeDuster® is to position it under storage
silos, for use before packaging. Installation at this position allows for the efficient
removal of any dust and streamers that have accumulated in the silos, including
the impurities created by dust surges.
Many existing pneumatic conveying systems are equipped
with older technology dust removal systems, such as scalpe-
rators, aspirators and elutriators. These systems cannot provide
the cleaning results required by modern manufacturing
plants. For most applications, a Pelletron DeDuster® can be
added under silos, before packaging, to improve the results.
Pelletron has developed models that fit on bagging machines
or can be moved between silos where a silo farm is in use.
Because of its ability to remove the micro fine, high electro-
statically charged dust particles characteristic of dense phase
systems, retrofitting existing systems with a DeDuster® has
become common practice. The flow sheet below shows
­examples of various solutions for the installation of DeDuster®
systems under silos.

3D model of mobile DeDuster® DeDuster® in operation Mobile DeDuster® for 60 t/h capacity preassembled in the shop
installed on bagging machine

PELLBOW® DIVERTER VALVE DIVERTER VALVE

PELLBOW®
INLET INLET INLET

DIVERTER VALVE DIVERTER VALVE

PELLBOW®
BULK SILO BULK SILO BULK SILO PELLBOW®

PRODUCT 1 PRODUCT 3 PRODUCT 2

ROTARY VALVE ROTARY VALVE ROTARY VALVE

FILTER FAN FILTER FAN FAN

FILTER

DEDUSTER® DEDUSTER® DEDUSTER®

PRODUCT OUTLET PRODUCT OUTLET PRODUCT OUTLET BLOWER

CYCLONE CYCLONE
CYCLONE
BUFFER HOPPER HEAT LINE 1
RAIL TRUCK EXCHANGER FILTER
ROTARY VALVE ROTARY VALVE ROTARY VALVE
PELLBOW®
BLOWER

COLLECTION DRUM COLLECTION DRUM COLLECTION BAG COLLECTION DRUM

PELLBOW® HEAT LINE 2
EXCHANGER FILTER

DeDuster® installation solutions PELLBOW®

BLOWER

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HEAT LINE 3
EXCHANGER FILTER
 DeDuster® Anthology –
The Complete Guide

DeDuster® Applications for Other Industries

How Versatile is the DeDuster®?
Pelletron has developed several solutions to address unique customer
­applications. Besides the cleaning of plastic pellets, the DeDuster® can be
used for cleaning dry bulk solids in the food, mineral and pharmaceutical
industries. Some examples for materials that require cleaning are:

Rice, corn, peanuts, coffee beans

Iron ore, special sand, wood pellets
Tablets, pills
And many more…

Removal of dust is often necessary because of the environ-

mental challenge it creates. Pelletron developed a special,
wear-resistant DeDuster® for cleaning iron ore to address the
health concerns associated with iron ore dust in the air and to
save energy by reducing the dust that hinders the melting
process.
DeDuster® for cleaning iron ore pellets
Our standard DeDuster® systems have capacities ranging
from a few pounds (kilograms) up to 200,000lbs (100 tons).
For applications that require higher capacities, Pelletron has
built custom models capable of processing several hundred
tons per hour. For installations with inclined silo outlet pipes,
the OS-DeDuster® (OffSet) was developed. For narrow pack­
aging lines, the DO-DeDuster® (single inlet and Dual Outlet)
was designed. Pelletron also provides wash down DeDuster®
systems designed for cleaning with water between product
changes. Pelletron continues to respond to customer requests
for unique applications.

Fan for iron ore cleaning

9
Systems Configurations

Open loop dedusting system with cyclone

An open loop system is recommended for processes with A closed loop system is recommended for standard operations
­frequent product changes or for lines with frequent color changes with the same or similar product grades or for inert gas appli-
in order to avoid cross contamination. Filtered fresh air is cations. A push/pull wash air fan supplies the wash air and
­pushed from a wash air fan into the DeDuster® supplying the pushes it into the DeDuster®. The dust is separated by the
cleaning air. A second exhaust air fan pulls the dusty air into baghouse dust collector and dropped into a dust container.
a cyclone or baghouse dust collector. The dust is separated in The cleaned air is returned to the fan.
a dust collector and dropped into the dust container. The cleaned
air is then released into the atmosphere.

Open loop dedusting system with baghouse filter

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 DeDuster® Anthology –
The Complete Guide

Closed loop dedusting system with

cyclone CCD-system (patented)

As an alternative to a baghouse, there are also Compact ­Cyclonic DeDuster® systems are available in open loop and closed loop
DeDuster® (CCD) systems available, a closed loop application versions, as well as in configurations for air tight systems
solution with a cyclone and an inline filter. The dust is separated with inert gas or clean room applications. Wash down ver­sions
by the cyclone and dropped into a dust container. ­Remaining for wet cleaning are also available upon request.
fine particles are separated using an inline filter. The cleaned
air is returned to the fan.

Closed loop dedusting system with baghouse filter

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Selecting the
Right Dedusting System

To aid in the selection of the best dedusting solution, a free-of-charge dedust-

ing test at the Pelletron test lab is suggested. Once the type and quantity of
­fines present is determined, a suitable DeDuster® configuration can be recom-
mended. For the very fine dust created in dense phase systems or for high dust
volumes, a dust collector with bags is usually the best solution. For systems
with coarse dust, typical after dilute phase or regrind operations, a cyclone with
an inline filter is the preferred technology. For systems with high streamer con-
tent, a cyclone is usually the recommended selection. As a result of testing of
over 3,000 kinds of bulk material, Pelletron has the experience to select the
proper system configuration to meet any customer requirements.

One of the most important design considerations for a dedust-

ing system is the selection of the fans. Fan sizing is affected
by the length, diameter and number of elbows in the duct
work, the pressure loss due to filters in the system and the
pressure loss and air volume requirements of the DeDuster®.
Pelletron engineers take these variables and the properties of
the material to be cleaned into consideration when determin­
ing the air volume and pressure needed for the best cleaning
results. Fan with manual damper HEPA-Filter with door open

The manual solution for the air management of a fan is the use of
mechanically operated dampers. These dampers are adjusted at Some applications require the use of HEPA-filters, in conjunction
start-up and can be readjusted easily in case of product changes. with the standard system configuration. Because of the high
Pelletron also offers variable speed drives for fans which can be pressure loss of these filters, the design and selection of the
­operated and regulated from a remote control station. These drives fan(s) becomes even more critical. HEPA-filters are used in clean
­allow for proper system balance and affect energy ­consumption room applications or for the dedusting of plastic pellets for use
­giving the end-user the ability to manage costs. in the electronic and optical industries.

Fans, bag house and cyclones for a dedusting system

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 DeDuster® Anthology –
The Complete Guide

Dedusting Test Facilities

Pelletron maintains a test lab to provide free-of-charge

cleaning tests and detailed digital test reports for customers
worldwide. There are two wet test methods established in the
market, the European FEM 2482 method and the ASTM Standard
D-7486-08. The FEM procedure defines dust content in three
classes: Type A from 63µm to 500µm, Type B from 45µm to
500µm and Type C from 20µm to 500µm. The newer ASTM
Standard defines the wet test measuring of dust particles
from 1.6µm to 500µm. Pelletron recommends the use of the
ASTM Standard because it covers the entire dust spectrum,
including the micro fine dust produced in dense phase systems.
For the exact measurement of the dust particles, Pelletron devel­
oped the wet test device, tradenamed FineAlyzer®. FineAlyzer®, Pelletron Corporation’s wet test device

Research & Development

Dusty product inlet

Continuous testing has helped to define customer require-

ments and has led research and development efforts to the
creation of the X-Series DeDuster® and the round RC-Series
Dusty air outlet
DeDuster®. These new DeDuster® models were targeted at
applications that ­required lower construction height and
­reduced consumption of cleaning air.

Pelletron believes that creativity is an integral part of the innovation

process. Our engineering and design staffs are all involved in Clean air inlet
the strategic, creative development of new products. Pelletron
Clean pellets outlet
understands that every process is different because parameters
often vary considerably. In many cases, a ready-made solution
is not possible. In close cooperation with our customers, we
are able to find the best solution through lab testing in order
3D model of RC DeDuster®
to achieve the ideal process under their pre-defined conditions.

An example of Pelletron creativity is the development of the

mobile DeDuster® system for installation on top of ­bagging
machines. This solution provides the highest flexibility in a silo
farm with packing requirements. A 3D drawing of this type of
mobile unit is shown on page 15.

The new RC DeDuster® in use for lab testing

13
P400 to P2000 are equipped XP15 to XP900 are equipped
with double wash decks with double wash decks

DeDuster® Product Line

P-Series DeDuster® Original low height design XP-Series DeDuster® X-tra low height & energy consumption

DeDuster® type capacity range in lbs/h in kg/h DeDuster® type capacity range in lbs/h in kg/h
P1 50 – 150 20 – 75 XP5 650 – 1,100 300 – 500
P5 100 – 600 50 – 300 XP15 1,000 – 3,500 600 – 1.600
P10 500 – 1,200 250 – 600 XP45 8,000 – 11,000 3.500 – 5.000
P30 1,000 – 3,500 600 – 1.600 XP90 12,000 – 22,000 5.500 – 10.000
P50 3,000 – 5,500 1.500 – 2.500 XP180 20,000 – 45,000 9.000 – 20.000
P80 5,000 – 9,000 2.300 – 4.000 XP360 60,000 – 90,000 27.000 – 40.000
P120 8,000 – 14,000 3.500 – 6.500 XP540 80,000 – 130,000 36.000 – 60.000
P200 12,000 – 22,000 5.500 – 10.000 XP720 120,000 – 180,000 54.000 – 80.000
P400 20,000 – 45,000 9.000 – 20.000 XP900 150,000 – 220,000 70.000 – 100.000
P600 40,000 – 65,000 18.000 – 30.000
P800 60,000 – 90,000 27.000 – 40.000
P1200 80,000 – 130,000 36.000 – 60.000
P2000 120,000 – 220,000 54.000 – 100.000

Note: Selection of the DeDuster® model depends on the bulk density of the product being cleaned, the shape of the pellets
and the type and quantity of the fines.

RC-Series DeDuster®

The RC-Series offers low height DeDuster® options designed for

a wide range of products with capacities up to 100,000lbs/hr
(90.000kg/hr). The round design allows for a reduction in
height and lower energy consumption. The larger sizes are
available upon request.
DeDuster® type capacity range in lbs/h in kg/h
RC1 10 – 750 5 – 350
RC20 3,000 – 5,500 1.500 – 2.500
RC45 9,000 – 11,000 4.000 – 5.000

Wash Down DeDuster® Wide Body Design

Wash down configurations are available for most DeDuster® For some retrofit applications, the available height is not
­types. The design allows the cleaning with water and easy access ­sufficient for the installation of a standard DeDuster®.
to all areas of the DeDuster®. ­Pelletron offers a wide body version of its P- and XP - Series in
order to reduce the construction height.

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 DeDuster® Anthology –
The Complete Guide
C-20 DeDuster®
The lightweight C-20 DeDuster® weighs 20 lbs (9 kg) and requires
only 9.5 in (240 mm) for installation between the hopper loader
and inlet hopper of an injection molding machine. The high
cleaning efficiency offers exceptional results. It features stainless
steel construction, 110 or 220 V operation and only ­consumes
2-3 CFM (3.4-5 m3/hr) compressed air at 20-30 psi (1.5 – 2 bar)
pressure.

OS-Series
This DeDuster® has an offset inlet/outlet design. It can be used
for applications with inclined piping or other configurations that
require an offset design. Various sizes are available. Others can
be designed based on unique customer requirements.

DO-Series
This DeDuster® has a single inlet and a dual outlet. It can be
used for special applications where narrow or shallow
­packaging machines are installed or for other configurations
that require a dual design. Various sizes are available and
others can be designed based on unique customer require-
ments.

Polished DeDuster®
For special, high grade resins, mirror polishing of the DeDuster®
is required (buffing 400). All DeDuster® types can be ­supplied
in polished versions.

Mobile DeDuster® Systems

Any DeDuster® system can be supplied as a mobile unit.
Mobile units can be installed on rails, on a mobile stand or
installed on a bagging machine.

Wear-Resistant DeDuster®
For high abrasive bulk materials, a wear resistant DeDuster® is
necessary. All DeDuster® types can be supplied in wear resistant
versions.

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 It’s clean

Pelletron DeDuster® Systems

are Installed All Over the World
Pelletron has supplied more than 2,000 DeDuster® systems to
companies in more than 50 countries. Pelletron can retrofit
solutions for most any type of system configuration due to
the wide range of DeDuster® types available. The DeDuster®
is the most chosen dust removal system when new plants are
designed and built.

Whenever high quality end products are the goal, customers

around the world choose the Pelletron DeDuster® to maximize
success.

fsb-welfenburg.de

Pelletron Corporation pelletroneurope GmbH

Corporate Headquarters European Headquarters
1866 Colonial Village Lane Ahornstraße 28
Lancaster, PA 17601 88285 Bodnegg
USA Germany
BDD E02/14

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www.pelletroncorp.com www.pelletroneurope.com
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