What's new in compounding & mixing.

There will be lots of new machines and new suppliers in continuous compounding, and a smaller collection of improved batch mixers and blenders.

New machines, as well as redesigns and incremental improvements of existing units, will be on show at NPE. Of note also are a number of new suppliers of continuous compounders and downstream equipment. Here's a preview of the first-time looks you'll get at compounding extruders, downstream equipment, controls, batch mixers, and blending systems.

CONTINUOUS COMPOUNDERS

Killion Extruders, Inc., Cedar Grove, N.J., will show off its new KZS series of segmented single-screw extruders for compounding (see PT, April '91, p. 113). Available in 1 1/2- and 2-in. versions, these modular units are aimed at short-run compounding or devolatilization where screw and barrel arrangements must be changed frequently. The extruders' L/D can be set at six different rations between 20:1 and 40:1, and come with two vented sections with plug and diverter, and injection and transducer ports.

Another relative newcomer to compounding, Davis-Standard Div. of Crompton & Knowles Corp., Pawcatuck, Conn., will exhibits its D-Tex 69-mm twinscrew compounding extruder. The new unit is part of a line ranging from 30 mm to 128 mm, based on technology from Japan Steel Works (PT, Oct. '90, p. 26). One interesting feature is a gearbox design offering users the choice of running in corotating or counterrotating modes, or both, with the shift of a single lever.

A paired continuous mixer and discharge extruder will be featured by Kobe Steel, Ltd. The configuration combines the Mixtron NCM counterrotating twin-rotor unit, extruder, valve, and control panel on a common base. Mixing and extrusion can be separately controlled, enabling the selection of optimum processing conditions for a wide range of materials (PT, Jan. '89, p. 70).

A continuous mixer/extruder combination will also be on hand at the booth of Farrel Corp., Ansonia, Conn. This will be a prototype second-generation Compact Processor (CP), consisting of a continuous mixer mounted over a short, hot-feed pumping extruder. The latest version incorporates new materials of construction for longer life, improved controls for greater flexibility, and new mechanical configuration for quick process changes and ease of maintenance.

Farrel's CP prototype will be part of a second new introduction: an integrated Technolab for R&D, process development, and production support. The Technolab combines several units into one line and includes Banbury mixers, Continuous Mixers, CPs, Polymill roll mills, Polycal calenders, Polypress test-sample presses, and Polyscrew single-and twin-screw extruders.

Berstorff Corp., Carlotte, N.C., will exhibit the latest versions of its line of ZE corotating twin-screw extruders, which have gearboxes offering higher service factors and lower noise. A 43-mm ZE 40-A will be displayed as part of the Modular Engineered Process Package (MEPP), which is said to be a cost-effective use of computer technology for extending the modular design concept to systems.

Berstorff will also have preliminary information and a number of other new items not on display. A high-surface-area, self-wiping vacuum reactor, called the Thin Film Reactor (TFR), is due for official introduction at this month's SPE ANTEC in Montreal. The pilot version users 10 vertical intermeshing screws with L/D rations of 10, 20, and 30:1, and will be offered in apex and planetary configurations.

Other new developments from Berstoff to watch for: additional sizes of twin-screw reactor/devolatilizers, an updated twin-screw compounder for highly filled applications, and in-line compounding/extrusion lines for producing finished products.

IN-LINE MIXING/EXTRUDING

In-line compounding and shape extrusion lines will be featured at other exhibits as well. Egan Machinery Div. of John Brown Inc., Somerville, N.J., will display a 47-mm corotating twin-screw extruder in a coextrusion setup with a 2 1/2-in. single-screw extruder, R.V. feedblock, four-component gravimetric blender, and downstream sheet line, all linked to Egan's CMR 1000 process control. Applications could inlcude production of multilayer structures with in-line compounding of highly filled materials and recycling of post-consumer scrap. The twin-screw unit is also available in 60-mm and 95-mm sizes.

An in-line compounding/profile extrusion system will be displayed by American Liestritz Extruder Corp., Somerville, N.J. Three new products will be featured. An 18-mm segmented twin-screw extruder, designed for lab and specialty applications, can process up to 15 lb/hr. Also on hand will be a new line of tangential, nonintermeshing twin-screws from 18 mm to 130 mm. The machines use segmented barrels and screws and reportedly offer higher drive horsepower and gearbox ratings than other nonintermeshing units. The new Macromatex microprocessor control for the complete compounding line was shown in prototype form at Interplas '90 in Birmingham, England (PT, Jan '91, p. 79).

Werner & Pfleiderer Corp., Ramsey, N.J., will demonstrate a reactive compounding process on a 40-mm ZSK40 twin-screw extruder producing a highly resilient sheet. Control of mixing history, component ratio, and temperature and pressure in the reaction zone is achieved with a WPC control. This system integrates a local control and data-acquisition computer with a host computer that archives data, generates process models, and uploads current data from the local station; operating setpoints are downloaded to the local station.

Abrasion-resistant screws and barrels also will be featured by W&P. New TME and ZME screw elements for ZSK twin-screws are said to provide distributive mixing with low energy input. The ZME is a self-wiping screw element. Screw elements and barrels protected by a new, wear-resistant PM alloy will also be shown.

Betol Machinery Ltd. of Luton, Bedordshire, England, is showing its BTS 60, 63-mm, corotating, intermeshing twin-screw extruder, described as a second-generation machine that was first shown at Interplas '90. The machine has segmented screws and barrel and 80-hp drive.

A corotating twin-screw extruder with segmented screws and barrel will be displayed by American Jet Stream, East Brunswick, N.J. A newly designed multistage reduction gear that reportedly reduces radial and torsional stresses will be on hand as well.

Battenfeld Extrusiontechnik GmbH of Germany will introduce to the North American market its newest Planex planetary-roller extruder, shown at K'89 in Dusseldorf (see PT, Jan. '90, pp. 77, 79). Barrel and spindles are ground from solid, resulting in optimal tooth geometry, higher wear resistance, and stress-free heat treatment. (Battenfeld is represented by Purnell International, Houston.)

A new, more compact power-coatings compounder, model PLK 70, will be introduced by Buss (America), Bloomingdale, Ill.

MORE LAB-SIZED

MACHINES

A number of lab-sized extruders (besides the American Leistritz model cited above) will be on hand. Werner & Pfleiderer will introduce a 30-mm ZSK30 lab twin-screw unit with control panel on the machine frame. Features include graphic displays, auto-tuning temperature control, network interface, data acquisition, SPC, and product recipe storage.

Berstorff will display its new ZE 25, a high-torque, 15-hp, 25-mm twin-screw machine with side-feeder capability.

A high-speed Wayne/ICMA twin-screw corotating extruder will be exhibited by Wayne Machine & Die Co., Totowa, N.J. The 35-mm, 36:1 unit, built in cooperation with ICMA of Italy, runs at up to 350 rpm with outputs to 90 lb/hr (PT, March '90, p. 19).

A new corotating twin-screw, 15:1 L/D tabletop compounder will be displayed by APV Chemical Machinery, Saginaw, Mich.

Two new pelletizing lines will be shown by Randcastle Extrusion Systems, Little Falls, N.J., one for research quantities of 10-100 g/hr, and the other for output up to 30 lb/hr.

DOWNSTREAM EQUIPMENT

Two new strand pelletizers will be displayed by Automatic Machinery Corp., Charlotte, N.C. The ASG 100 and ASG 200 (100-mm and 200-mm cutting rotors, respectively) are equipped with noise-reducing enclosures and a-c inverter motor, and can be cleaned out between runs without using tools. The ASG 200 can pelletize up to 23 strands with a throughput of 2000 lb/hr. Also on hand will be the ATG self-stranding dry-cut pelletizer. A new line of "Aqua-Silencer" strand pelletizers with outputs ranging from 850 to 3300 lb/hr will also be introduced by U.S. Extrusion, Inc., Hawthorne, N.J.

A mid-range hot-die-face pelletizer for rates up to 3000 lb/hr is being introduced by Beringer Div. of John Brown Inc., Marblehead, Mass. Werner & Pfleiderer will show its new intensively heated die plates for underwater pelletizing of polyolefins, shown at K'89 (PT, Jan. '90, p. 81; July '90, p. 65). The even heat distribution of these die plates reportedly means lower energy requirements, together with increased range of operation and higher on-stream factor with less risk of hole freeze-off.

Gala Industries, Eagle Rock, Va., is introducing a Removable Center Die for use with its underwater pelletizers. The die permits the user to change the number or size of strand holes without having to disconnect the heating medium.

Welding Engineers, Blue Bell, Pa., will exhibit the AST underwater pelletizer line, which offers throughput rates from 100 to 14,000 lb/hr. The company recently signed an agreement with AST (Automatismi Speciali per Thermoplastici srl) of Italy to distribute its pelletizers in North America.

Two new names in screenchangers will be on hand (see Extrusion section for more on screenchangers). Gemini Plastics Machinery of England (represented by Princeton Filtration Co., Upper Black Eddy, Pa.), will show its TS hydraulic screenchanger for twin-screw extruders and compounders. A relatively new company, Extek in Marblehead, Mass., is introducing its own line of hydraulic screenchangers from 2 to 8 in., aimed at compounding and extrusion. Features include one-piece body construction to ensure accurate alignment of bores; and filter cartridge design that maximizes the flow area and shields the slide plate from polymer flow, eliminating build-up of degraded polymer. Cartridge heaters are said to provide improved temperature control in the screenchanger body; internal heat pipes conduct the heat uniformly through the slide plate without wires or stream lines. Extek also represents the Chiva line of manual screenchanger from Spain (PT, May '90, p. 12).

BATCH MIXERS

Charles Ross & Son Co., Hauppauge, N.Y., is introducing a change-can mixer that combines two mixing technologies: double planetary mixer and high-speed disperser. Planetary blade and high-speed disperser each rotates on its own axis and on a simultaneous planetary motion around each other inside the mix can. Typical mix cycles are said to be completed in a fraction of the time required with other mixers.

Purnell International, Houston, is introducing the HM20 explosion-proof, medium-intensity lab horizontal mixer. In addition, the company will display a new Henschel drum-type mixer.

International Process Equipment Co., Pennsauken, N.J., will introduce the MTI M750/K2400 compounding system. The unit consists of two components: a 750-liter high intensity blender for PVC-type powders, and a larger cooling blender to bring the material down to ambient temperature. Mixer sizes are available from one gal to 2000 liters.

Premier Pneumatics, Inc., Salina, Kans, will introduce its Quick Clean ProBlend. Equipped with an instant-access hopper door with quick-release latches, the unit's mixing chamber and impeller are easily accessible for cleaning.

Processall Inc., Cincinnati, Ohio, is introducing a chemical reactor for the manufacture of polymers. Capabilities include mechanical fluid-bed action, pressure, temperature, and full vacuum.

American Barmag will display a batch mixer from Mixaco, a German company that it is now representing in the U.S.

BLENDING SYSTEMS

A new continuous gravimetric blender, the BG series, which will blend up to eight ingredients at rates to 5000 lb/hr, is being introduced by Process Control Corp., Atlanta (PT, April '91, p. 112). The company also will feature its new BV volumetric blender, and PC-based control system for setting recipes and monitoring functions.

Also making its debut is Process Control's Gravidfluff gravimetric scrap recycling system, designed to accurately control the percentage of scrap refeed into an extruder. The system uses a loss-in-weight fluff feeder to meter fluff into the company's patended RMT Refeed Machine (PT, Dec. '90, p. 63), which itself uses a "dual-hopper" approach to maintain a consistent proportion of scrap to virgin material at the extruder throat. Gravifluff is designed to use edge trim as well as roll and loose scrap, and may be incorporated into a complete Gravitrol extrusion system (see p. 47).

K-Tron Vertech, Pitman, N.J., will spotlight its Gravi-S low-rate Graviblend feeder module. The unit is said to provide fast, no-mess ingredient changeover, yet still deliver material to the blend with high precision. Graviblend weighblenders now can be customized into configurations that handle from one to eight ingredients in low to high feed rates.

A.C. Hamilton & Co., Mississauga, Ontario, will demonstrate a new central control station linked to three weigh blenders, as well as a new self-loading volumetric blender.

Comet Automation Systems, Dayton, Ohio, will exhibit its new SmartDisk gravimetric blender designed to weigh, mix and feed up to five materials into the processing machine. The unit, whose metering and mixing capabilities are unaffected by the throughput of the processing machine, has a microprocessor that can store as many as 100 recipes.

Colormas of Telford, England, is introducing a blender specifically designed for blow molding machines that can blend two to four materials at up to 264 lb/hr. HydReclaim Corp., Fenton, Mich., is introducing a new series of computerized ratio/weight blenders. And Novatec, Inc., Baltimore, has three new types of weigh blenders, including a batch/blending system with [+ or -].1% accuracy that reportedly costs less than $9000.

Premier Pneumatics, Inc. will introduce a microprocessor-based Pro-Controller, which controls up to six ingredients. The unit converts auger revolutions to units of weight and furnishes gravimetric recipe information. Designed to work with company's Pro-Rate feeders and ProBlend mixers, it has storage for 150 six-ingredient recipes and performs all calculations required for calibration.