Leistritz Twin Screw Report Aug

9/6/13 Leistritz Twin Screw Report Aug. 2013

www.alec-usa.com/Control Systems for Extrusion.pdf 1/6

Visit Leistritz @ K2013, October 16-23, 2013 in Dusseldorf, Germany (Hall 16,F22) and see a ZSE-75 MAXX process 80% filled compound and other

revolutionary TSE developments

The following is included in this e-tech newsletter:

Leistritz Twin Screw Extrusion Workshop to be held December 4-5, 2013Article: Liquid injection into the TSE process sectionTechnical tip: How to calculate Specific VolumeFeatured model: ZSE-60 MAXXUpcoming exhibit/presentation schedule

Leistritz Twin Screw Extrusion Workshop to be held Dec. 4-5, 2013

Since 1990 5000+ have attended Leistritz educational programs!

Leistritz will host its’ annual Twin Screw Extrusion Workshop on December 4th and 5th in NJ. Asalways, classroom sessions are supplemented by "hands-on" twin screw extrusion operatingexperience. A partial list of topics is as follows:

High speed, energy input (HSEI) twin screw extruder theory and designComparison to low speed, late fusion (LSLF) designsScrew design and process techniquesTechniques for dispersive and/or distributive mixingSequencing of multi-stage process operationsDevolatilization process techniques and practicesScale-up of the twin screw extrusion processFeeder and materials handling for pellets, powders and liquidsGear pumps and screen changersPelletizing: strand cut, water ring, and underwaterDirect extrusion for sheet, film, fibers and profilesReactive processingProcess troubleshootingControl and monitoring optionsScrew assembly and disassemblyMachine maintenance



Machine maintenance

“Hands-on” demonstrations at Leistritz NJ process laboratory will include:

Co-rotating and counterrotating twin screw extrudersDevolatilization of polymersDownstream addition of fillers, fibers and additivesDirect sheet/film extrusion with gear pump front-endFoam extrusion via supercritical injection

In addition to Leistritz staff, industry and academia also contribute to the program. To receive the

program agenda when finalized (on or about Oct. 1st) contact Sarah Scovens, [email protected].

To download a presentation from last years’ workshop entitled “Control Systems for Extrusion” by

Pete Palmer, Wolock & Lott…

Dates: December 4-5, 2013 Place: Classroom sessions are held at the Holiday Inn in Clinton, NJ. Equipment demonstrations areat the Leistritz Process Laboratory. Transportation is provided to/from the machine demonstrations. Cost: $780 (includes handout materials, lunches, and dinner on day 1)

To register for this program contact Sarah Scovens at 908/685-2333, X614 or [email protected].

To download a registration form for the Twin Screw Workshop …

Liquid injection into the TSE process section

A wide range of liquids can be pumped into the TSE process section….i.e. water, supercritical,plasticizers or even a melted/viscous polymer or rubber. Different type pumps may be specifiedbased on the viscosity range and changeover requirements for the liquid being introduced (pistonpump, gear pump, peristaltic pump, among others). The liquid is typically injected into downstreambarrel sections, and can be supplied as ambient, chilled or heated.

mailto:[email protected]




Dual ambient injection system with mass-flow gauges

Volumetric controls for liquids are typically very accurate. The mass flow rate can also be measuredand controlled by placing the liquid tank on load cells with loss-in-weight controller to control the pumpmotor speed. Alternatively, a mass-flow meter can be used to control and monitor the fluid rate to theextruder.

Example heated liquid feed stream to a TSE

Lower %’s of liquid injection (below 20% or so) can be injected in one location. Higher %’s, (70%+)require multiple injection ports along the length of the process section. Typical applications includethe injection of super-critical fluids (for foaming), injection of plasticizers/oils (i.e. for TPEs)

To download a liquid injection flyer..

Calculating Specific Volume (SV) in a twin screw extruder

Specific Volume (SV) represents the approximate volume for 1 L/D of the process section. Whenspecifying a TSE it’s important to know the free volume in the process section. It’s not as simple ascomparing screw outside diameters (OD) as different outside diameter/inside diameter (OD/ID)ratios are available. A smaller OD/ID ratio results in less free volume, and a larger OD/ID ratio inmore free volume. If a process was volumetrically limited, the attainable rate would be directly



more free volume. If a process was volumetrically limited, the attainable rate would be directlyproportional. To calculate a rough SV approximation the following formula can be used:

Specific Volume = .94 x (OD²-ID²) x OD/1000

Units:SV is denoted in cc/diameter of length OD = Screw outside diameter (each)ID = Screw inside diameter (each)

For example:

For a ZSE-60 MAXX twin screw extruder with a screw OD of 62 mm and an ID of 37.35 mm (a 1.66OD/ID ratio) the approximate SV is as follows:

SV= .94 x (62²-37.35²) x 62/1000 = 143 CC/DIA

This might compare to a TSE with a 58 mm OD and 1.55 OD/ID ratio with a corresponding SV ofapproximately 107 cc/dia. See below for a comparison of the different OD/ID geometries:

Featured HSEI TSE: ZSE-60 MAXX twin screw extruder

The ZSE-60 MAXX is ideal for mid-rate compounding wide ranging formulations at rates of up to4,000+ lbs/hr. It’s small enough for change-overs and big enough to pump tonnage as needed.



ZSE-60 MAXX twin screw extruder with underwater pelletizer

Some basic ZSE-60 MAXX specifications are as follows:

Screw diameter 62 mm

Flight depth 12.3 mm

OD/ID ratio 1.66

MAXX torque rating 3750 NM

Industry events where Leistritz will participate

SPE FOAMS – 9/11-12/13, Seattle, WA; Charlie Martin presenting “Twin Screw Extruder (TSE)Developments for Novel Foam Processes”SPE Color and Appearance RETEC Conference – 9/22-24/14, Baltimore, MD; tabletop exhibitK 2013 - 10/16-23/13, Dusseldorf, Germany; big display, a lot of new stuffAAPS 2013 – 11/10-14/13, San Antonio, TX; 20’ displayLeistritz Twin Screw Extrusion Workshop – 12/4-5/13, Somerville, NJAMI Compounding World Forum – 12/10-11/13, Philadelphia, PA; Bert Elliott presenting “Tipsfor Optimizing Twin-Screw Extrusion”Plastec West – 2/11-13/14, Anaheim, CA; 15’ displayNatureWorks® Innovation Takes Root – 2/17-19/14, Orlando, FLInternational Polyolefins Conference – 2/23-26/14, Houston, TX; tabletop exhibitSPE Continuous Compounding Topcon – 3/11-13/14, Cleveland, OH

To receive more information on anything contained in this newsletter [email protected]




169 Meister Ave.Somerville, NJ, 08876, USA

ph: 908/685-2333e-mail: [email protected]


http://www.leistritz-extrusion.com/

Leistritz Twin Screw Report Aug

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