May 14, 2007

11 Min Read
Size Reduction

pbs0705p8b.jpgHammer Mill
With a combination of high capacity and compact size, the Type 1200 hammer mill offers a large feed inlet that is ideal for bulky materials from batches of a few pounds to over 600 lb/hr. Features include a simple design, minimal power requirement, large output, minimum floor space, large effective screen area, extended feed table to increase safety, a safety switch that prevents the mill from starting while the hood is open, cast-steel construction of the mill body, easily accessible parts, and operating speeds up to 3600 rpm.
Glen Mills Inc., Clifton, NJ 973-777-0777

pbs0705p8c.jpgPin Mills
Type PST pin mills are used for fine to finest grinding of dry, brittle, or hard-to-grind materials to a fineness of d50 = 5 µm. The mills are centrically fed by a dosing mechanism and magnetic separator, and the grinding is done by impact and whirling between the concentrically mounted pin rows of the rotating and the stationary disks. The particle size is determined by the speed, number, and type of pins. These high-speed counter-rotating machines operate without a screen. Pin rows, concentrically fixed on the rotor and stator disks, reduce the particles. Special designs for cryogenic applications are available.
Pallmann Industries Inc., Clifton, NJ 973-471-9773

pbs0705p12b.jpgHammer Mills
These hammer mills are manufactured in sizes from 2-hp laboratory units to 500-hp heavy industrial mills and are available in carbon or stainless-steel construction. The heavy-duty Model 13100 can grind a variety of materials to virtually any finished size desired by making a simple change to the screen size employed. More than 250 mills are available in a variety of sizes and styles to match the proper machine to exact needs. A free-of-charge testing service is offered, and customers are welcome to witness testing.
Schutte-Buffalo Hammermill LLC, Buffalo, NY 716-855-1555

Hammer Mills
Designed for demanding operations, these rugged, high-efficiency hammer mills are capable of fine-grinding either friable or fibrous materials. The HM series hammer mill features double-wall box construction, a mechanical-steel tube base, double-row spherical roller bearings, full-access doors, bidirectional inlets, a patented regrind chamber, and abrasion-resistant wear liners. The Champion series hammer mill features an air-swept “tear circle” design, bidirectional inlet flow director, dual-hammer position, one-piece access door on each side, patented regrind chamber, inboard and outboard bearings, a center-hinged screen carriage, replaceable AR235 wear liners, a universal motor-mount system, and gravity-flow bottom discharge.
Champion Hammermill, Waterloo, IA 800-366-2563

pbs0705p13c.jpgClassifying Impact Mill
The Powderizer is a classifying impact mill capable of reducing powders to less than 10 µm. Because its independently driven impact milling and air classification technologies are combined in one unit, it can produce a consistent product despite variable feed conditions and can produce several different products from the same feed with simple “dial in” adjustments. The unit can process heat-sensitive materials, making it ideal for chemical, food, pharmaceutical, and mineral applications.
Sturtevant Inc., Hanover, MA 781-829-6501

Rietz disintegrators can shred and wet-grind many fibrous and extremely tough materials. They are also used to fine-pulp, disperse, and homogenize a variety of materials in food, chemical, pharmaceutical, and nutraceutical industries. Their sanitary design is USDA and FDA compliant. An endless combination of screens, hammers, inlets, and discharges allows the operator to perform a variety of functions with a single machine, and even more when coupled with an ACVF controller. Models from 3 to 125 hp are available with possible tip speeds of up to 115 m/sec. Inlet nozzles allow introduction of steam, water, flavorings, reagents, and other additives. With a single band clamp and hinged covers, the design is easy to clean, allowing easy access to all product contact surfaces.
Bepex International, Minneapolis, MN 612-627-1415

pbs0705p16b.jpgFine Grinders
These fine grinders offer three key benefits. The first is a uniquely designed outboard bearing system that prevents product contamination into the bearings, providing an easier-to-clean mill housing and easier maintenance. The second is dual O-ring door seals that create a 360° positive seal of door to housing and grinding chamber, resulting in completely dust-tight and quiet operation. Finally, the larger housing of the grinders offers a slower ground-product exit speed, ensuring a cooler product, which is important when grinding heat-sensitive products such as powdered sugar and resins. The grinders provide high capacity per horsepower and have a low air requirement, resulting in lower operating costs.
Prater-Sterling, Bolingbrook, IL 630-759-9595

pbs0705p16c.jpgShear Mill
The Boston Shearmill provides high shear rates and tip speeds for maximum droplet and particle size reduction. This unit is well suited for processes requiring the milling of soft particles to less than 1 µm or hard particles down to 1–2 µm. In many cases, it can accomplish these feats with a single pass. Models are available from 15 to 125 hp, providing throughput from 5 to 250 gal depending on feed rate and viscosity. All models feature an exclusive single mechanical quench seal rated for 700 psi and comply with 3-A standards (#36-01).
Admix Inc., Manchester, NH 603-627-2340

Designed for cryogenic milling of aluminum powders, the S-50 attritor has a special cover with a Teflon shaft seal for ultimate grinding results at low temperatures. It features a vent port for liquid nitrogen as well as ports for thermocouples. The unit is designed with a jacket around the exterior of the tank to maintain full vacuum at temperatures as low as –320°F. Featuring a gross tank volume of 81 gal and a media volume of 37 gal, the attritor is constructed with a 40-hp motor with variable-frequency drive (VFD). Since the mill is required to be explosionproof, the VFD is mounted outside the hazardous area. In addition, an operator station with start-stop push buttons, a speed potentiometer, and a dual-meter station are mounted on the machine. The dual-meter station is programmed to display rpm and amperage but can also be programmed to display power consumption, percent torque, etc. The unit is suitable for long-term, heavy-duty operation.
Union Process, Akron, OH 330-929-3333

pbs0705p26b.jpgLump Breaker
The Crumbler reduces material agglomerates to conveyable particle size. The lump breaker has dual, counter-rotating shafts with eccentric rotor blades running between companion stators. In the quick-cleaning model, the rotating shafts are designed for ease of cleaning, requiring no tools for assembly and disassembly. The unit is easily integrated into bulk bag dischargers, container dischargers, hoppers, or other process equipment configurations.
NBE Inc., Holland, MI 616-399-2220

pbs0705p26c.jpgIn-Line Pipeline Delumper
The Pipeline Delumper is a powerful in-line processor that crushes, disperses, and suspends tough solids in fully enclosed pipe systems. This unit eliminates blockages, works the stream to free flow, and prevents damage to pumps and other equipment. It is suitable for wet, dry, pressure, or gravity systems. The ultracompact, straight-through unit is designed for easy installation. This fluid-tight, pressure-rated unit has the full throughput capacity of the pipe to which it is connected. Its working principle employs rugged impeller teeth passing through a heavy bar grating to reduce the size of the product. These teeth completely clear the slots of the bar grating while cleaning the entire pipe cross-section area. A choice of packing seals or mechanical seals is provided in a cartridge housing. The machine is fabricated in carbon and stainless steel in 3- to 30-in. pipe sizes.
Franklin Miller Inc., Livingston, NJ 973-535-9200

pbs0705p27b.jpgCentrifugal Impact Mill
The sanitary centrifugal impact mill (pin mill) provides coarse to fine grinding (325 mesh) of friable materials into controlled particle sizes, plus lump breaking and conditioning of fibrous materials. High-speed rotation of the inner disk accelerates the material entering the central inlet of the opposing stationary disk. Material travels to the periphery of the disks at high speed through five intermeshing rows of rotating and stationary pins, with tight particle-size distribution obtained by controlling the rotor speed. Setting the infinitely variable rotor speed between several hundred and 5400 rpm allows coarse grinding and deagglomerating as well as fine grinding.
Munson Machinery Company, Inc., Utica, NY 800-944-6644

pbs0705p28b.jpgCrusher and Lumpbreaker
The Flow-Smasher crusher is a heavy-duty, high-torque, high-capacity crushing machine designed to reduce large chunks of friable materials to a consistent, free-flowing size, preventing line blockages and making downstream operations more efficient. It is available in most construction materials and with numerous design options—including polished, sanitary designs. It is available in standard sizes from 8 × 8 in. to 48 × 48 in.
Atlantic Coast Crushers Inc., Kenilworth NJ 908-259-9292

pbs0705p28c.jpgClassifier Mill
This classifier mill offers the combination of two-stage closed-circuit grinding with inter-stage classification. It was developed to handle higher volume and very fine–size reduction jobs, and it fine-grinds and classifies materials such as grain, sugar, spices, glazes, protein, gelatin, and cocoa. The mill utilizes a 3- to 200-hp motor and provides size reduction from 100 mesh down to low micron sizes. It combines classifying with grinding, and its unique design provides a narrow spread of particle size. All material ground in the first stage enters a classifying chamber. Particles larger than specified are rejected by the classifier, allowing only properly sized product to exit the mill. All rejected material is directed to the third stage, which is a separate part of the grinding rotor, where it is processed until it is ground to an acceptable size. The unit is especially useful on hard-to-grind materials and on a more-narrow particle-distribution curve than practical with the company’s M-series mills.
Prater-Sterling, Bolingbrook, IL 630-759-9595

pbs0705p29b.jpgProduct Containment System
The Product Containment System (PCS) contains the product inside the process components to prevent airborne dust from escaping into the atmosphere. The system also facilitates operation in an inert environment. The method used to contain the product is similar to isolator technology. The process area is kept in slight negative pressure to ensure that no powder migrates to the outside. Several features ensure a tightly sealed machine. The PCS uses a number of primary filters in the machine discharge. These filters are connected to a vacuum system that maintains the proper condition inside the processing chamber. A backpurge cartridge is used to draw process gas in from one filter to backpurge and clean another filter.
The Fitzpatrick Co., Elmhurst, IL 630-433-3120

pbs0705p31b.jpgRoller Mill
The Raymond roller mill is an air-swept vertical ring-roll mill that economically, efficiently, and simultaneously dries, pulverizes, and classifies clays, minerals, and manufactured materials that measure 5 or less on the Mohs’ scale. It is available in seven sizes with ring diameters of 30 to 86 in., capacities to 80 tph, and fineness from 20 mesh to 99.99% passing 325 mesh. It provides efficient control of product size with minimal power, resulting in flexible, cost-effective production. Applications include fire, bentonite, and kaolin clays; barites, gypsum, limestone, and hydrated lime; and phosphate rock, talc, coal, pigments, and phenolic resins. Equipment options include integral flash drying for moisture removal and static or dynamic classifiers.
Alstom Power Inc., Warrenville, IL 630-393-1000

pbs0705p31c.jpgLump Breaker
The Double Rotocage lumpbreaker breaks lumps, clumps, slabs, and blocks of wet or sticky material that build up and plug other lump breakers. Two counter-rotating rotors work together to quickly and efficiently break the lumps while keeping the material from building up on the rotors or the housing.
Wyssmont Company, Inc., Fort Lee, NJ 201-947-4600

The patented TurboTwin classifier is suitable for high-yield superfine classification of mildly abrasive materials such as limestone, talc, silica, graphite, barite, mica, and kaolin with fineness between 2 and 4 µm. The unit’s patented classifying wheel geometry permits high throughput rates and load factors at steep top cuts, making it an alternative to multiwheel classifiers. The classifying wheel permits extremely high speeds (i.e., peripheral speed up to 120 m/sec) with comparatively low energy consumption. The classifier bottom section is designed so existing machines can be retrofitted with the TurboTwin. Five machine sizes are currently available with drive powers ranging from 30 to 200 hp.
Hosokawa Micron Powder Systems, Summit, NJ 908-273-6360

Abrasive Application Materials
Company develops materials for abrasive applications on rotor mills and rotor dryers. The systems, which provide increased wear and offer a wide operating temperature range, consist of tungsten carbide tiles brazed to grinding plates. The systems are useful in drying applications. A ceramic tile insert system clamps in ceramic tiles for wear protection of the grinding liner. Rather than having to replace the complete liner, these tiles can be changed individually. The clamping arrangement allows the tiles to be attached to a backing plate without the use of adhesives, giving it a high upper temperature limit.
IPEC, Pennsauken NJ 856-665-4007

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