Materials handling.

Materials Handling 

With about 100 suppliers displaying products, materials handling equipment had a visible presence at NPE '91. Smaller seemed to be better this year, as scaled-down granulators, dryers, and hopper loaders were introduced, as well as novel conveying systems and metal separators.

WHAT'S HAPPENING IN DRYERS

As shop floor space becomes more valuable, manufacturers of resin drying equipment stressed the compact and lightweight features of their new units. One such example is found in new units from the Whitlock Div. of AEC Inc., Wood Dale, Ill. While most drying hoppers rely on height to ensure uniform flow, AEC has developed a series of low-profile units it says does the job even better. Reportedly, the new Mass Flow dryers use a flow of centralized process air feeding into the center of the material to eliminate the need for hopper-bottom screens and reduce the possibility of funnel flow problems.

Thoreson-McCosh, Troy, Mich., showed its new lightweight, machine-mounted desiccant dryer, the Dri-Pak 12/24. It has microprocessor-based digital display temperature control and operates on a single-blower, single-desiccant bed design.

Universal Dynamics, Woodbridge, Va., also displayed its latest compact dryer, the UDC-30. It has a throughput of 30 cfm of material and its hoppers are available in aluminum or stainless steel. The UDC-30 provides continuous drying via an electric motor rather than compressed air. It weighs 90 lb and can be either portable or hopper-mounted, a spokesman said.

The Conair Group, Wexford, Pa., showed its new line of mini dryers developed in conjunction with Waters Research, Elgin, Ill. The dryers, Conair's first twin-tower units, use oversized desiccant beds for continuous -40 F air temperature. Reportedly, they can dry 15 cfm.

Another small dryer was introduced by Colortronic, Puyallup, Wash. The T-92, designed for use with granular thermoplastics, can dry about 30 lb/hr of nylon, a company spokesman says.

Carter-Day Co., Minneapolis, re-engineered its Spinaway dryers and has reportedly improved the units' performance, while making them well-suited to drying regrind. Among the new features is a pellet-free rotor whose round profile creates an easy-to-clean surface in which the inner cavity is completely sealed off from any external product contact. Other additions include three seals to enhance bearing protection and a leak-detect port that indicates the first seal has failed and needs replacement. The units are available in a variety of sizes and can reportedly dry from 3000 lb to 130,000 lb/hr.

Hailed as a breakthrough in air diffuser technology, Novatec Inc., Baltimore, introduced a removable tubular diffuser it says will be a standard feature in all its modular hoppers up to 1000 lb. The patent-pending diffuser, which replaces conical diffusers, is more compact than its predecessors and can reportedly be easily removed for fast cleaning and quick material changeover. Tests show the tubular diffuser achieves uniform air flow through the hopper with no detectable hot or cold spots in the resin.

MOVING AND LOADING MATERIAL

Novatec was also among a group of suppliers introducing new material-conveying systems or controls. The company's MCS-206 and MCS-206R six-station conveying control systems are designed for use on extrusion and film production lines, as well as by small injection molders or large molders with a few machines dedicated to one product line. The microprocessor-based units can operate one- to six-station conveying systems and include seven-color graphic display, LED indicators for station valve loading and quick-connect terminal blocks.

The second conveyor controller Novatec introduced is designed to manage up to 32 stations and three vacuum power units. The system features separate on/off controls for each loading station and power unit, an 80-character alphanumeric display, and a seven-color graphic panel with red, green and yellow LEDs for each station and power unit to easily identify that component's status.

A proportioning valve from Colortronic was shown for the first time in North America. The valve, which can feed different materials to as many as 10 lines, has been used in Germany for about three years, a spokesman says. It is designed to replace manual coupling stations in quick-materials-change systems and can be cascaded to double its output.

AEC/Whitlock introduced an addition to its TurboVac conveying system. The new portable Mini TurboVac can be used as a standalone unit or as a component in a total system. Typical applications, AEC says, are moving beside-the-press dried resin to a throat feeder or loading additives into an additive feeder. The new unit has a 1/3-hp ring compressor fan that can load as much as 250 lb/hr over 50 ft. An in-line filter in the 1 1/2-in. conveying line protects the fan motor from dust and fines. A standalone, single-station, time-fill control can convert the Mini TurboVac into a self-contained conveying system.

For years processors have lamented over how to move sensitive materials through high-velocity handling systems while maintaining a high level of quality. The answer, according to Buss America, Bloomingdale, Ill., is to convey the material slowly. The company's new Waeschle Rotorconveyor RCG pneumatic conveying system uses a rotary valve axially sealed for low air leakage and features a non-chopping feed port to protect pellets from damage as they flow through. Reportedly, product quality can be controlled by varying the valve rotation speed. The Rotorconveyor RCG is available in throughputs from 1 1/2 to 40 tons/hr.

For moving low-density, oddly shaped materials, Kongskilde Ltd., Exeter, Ont., introduced its FVO In-Line Venturi that can be connected to all the company's blowers and piping. The unit reportedly eliminates any bridging or lodging at the point of entry, impeding the flow into the air stream. The venturi has an adjustable opening that can create a varying degree of suction. It reportedly works well with film trim, expandable polystyrene and PET bottles up to 2 liters in size.

A central loading system with operator interface at each station, permitting machine operators to adjust load, time and ratio at their particular station, was introduced by Thoreson-McCosh Inc. Digitally controlled, the stations of the new system display setpoints and other loading information necessary for efficient operation, a company spokesman says. Thoreson-McCosh also showed new microprocessor-controlled vacuum loaders with an improved flapper-door that reportedly provides extra clearance and permits more material to be loaded into the hopper. A flexible seal ensures proper operation even if a bit of material is trapped in the closure.

The new RL500 Superloader II from Cactus Machinery Inc., Markham, Ont., is a pneumatic airpowered integral hopper loader designed to load both virgin and regrind up to a 50/50 mixture. Made of spun aluminum, the loader stands 17 1/2 in. high. It does not use a vacuum motor nor does it require a selector valve to switch from virgin to regrind. Solenoid valves control the air flow to each material. The unit has a 30-sec loading cycle that mixes regrind and virgin resin through the use of a timer. For every second regrind is conveyed, the time virgin is loaded decreases by one second (5 sec of conveying regrind would mean 25 sec of virgin). Cycles continue until the hopper is filled. The unit costs about $1895.

Conair Franklin, Franklin, Pa., introduced its new direct-feed C-Loader and single-phase vacuum pump for use in self-contained manufacturing cells. The C-Loader bolts directly to the throat of an injection molding machine, using a sensor to signal the need for more material. Different-sized plexiglass tubes are available so a processor can see what's going into the machine. The loader's vacuum pump then draws in about 6 lb of material and the material is deposited directly to the machine throat, eliminating the need for a dump valve or intermediate machine hopper. The loader costs between $600 and $700. Complementing this unit is Conair's new single-phase pump. The 7/8-hp pump can convey pellets and regrind up to 50 ft at rates of more than 500 lb/hr, Conair says. It requires 115 volts and 12 amps to operate.

Another small-capacity vacuum loader introduced at NPE is the VL-5, a 1/8-cu-ft-capacity unit from Novatec. It has a stainless-steel chamber and lid sealed together with a quick-release clamp and safety lock for easy access to its polyester filter. Novatec recommends this unit for use with material hoppers up to 200-lb capacity and for feed rates as high as 500 lb/hr.

AEC also introduced a small hopper loader--a 2 1/2-lb capacity modular Mini AutoLoader designed to load up to 500 lb/hr of free-flowing pellets or clean regrind. A new cartridge filter mounted in the hopper loader's cover reduces filter loading by directing material away from the filter. Combined with the tangential inlet AEC has been using for years, the new filter reportedly reduces material degradation and dusting.

The JIT loader from Comet Automation Systems Inc., Dayton, Ohio, is really just a smaller version of the company's standard hopper loader, a spokesman says. Utilizing the same motor and controls as the larger hopper loaders, the JIT loader holds only a few shots and is designed for use on small injection molding machines.

The Autohopper from the Webtech Div. of Webb Technologies, Delta, B.C., is reportedly a fully automatic loader. Powered by compressed air, it can be mounted directly on the feed throat or as an ordinary hopper loader. Webtech says the unit can load as much as 400 lb/hr of virgin or regrind and uses an electronic timer to regulate filling. It employs an automotive air filter equipped with wire mesh to prevent clogging, Webtech says.

MANY NEW GRANULATORS

A series of compact, under-the-press granulators are new from the Gloenco-Newport Div. of Battenfeld Gloucester Engineering, Gloucester, Mass. The two models in the LP series stand 35 1/2 in. high. The granulators, which have 6-, 8-, 10- or 12-in. throat openings, can be used in thermoforming, injection molding and extrusion systems. Throughput can reach as high as 250 lb/hr with a 5/16-in. screen, Battenfeld says. Prices start at $6000.

Several other companies introduced new granulators and grinders:

* Colortronic debuted two new small sprue granulators. The M 252 is a slow-running (120 rpm) machine with a transverse rotor that can reportedly handle sprues as large as 7 x 15 3/4 in. The M 82 is a smaller unit designed for sprues and runners up to 2 3/4 x 4 in. Both are available with either steel coil or manual feed.

* A large-parts granulator from Polymer Machinery Corp., Berlin, Conn., is designed to reduce thinwalled blow molded, injection molded and vacuum formed parts at throughputs as high as 700 lb/hr. The machine is available with either a 16 x 24-in. or 16 x 32-in. feed throat and 25-30 or 30-40 hp motors. They stand 60 in. high and use a counter-slanted blade design for uniform granulate with less energy consumption.

* A low-speed (185 rpm) grinder from A.C. Hamilton and Co. Ltd., Mississauga, Ont., the MN 624R, has six staggered rotor knives and two adjustable bed knives, resulting in better quality regrind and longer times between knife changes. It can reduce about 100 lb/hr of scrap, a Hamilton spokesman says. Cost is about $4000.

The new 1214 granulator is a higher throughput model from Hamilton. The 1214 has a 15-hp motor and tangential feed that can reportedly reduce about 800 lb/hr of scrap. It uses three rotor knives, two bed knives and a scissor-cut design. Hamilton says the unit's screen can be removed for cleaning in about 20 sec. The price of the unit is about $7650.

* The G2045M, a large central-station granulator from the Nelmor Div. of AEC, North Uxbridge, Mass., has a 20 x 44 1/2-in. cutting chamber and can reportedly process as much as 2000 lb/hr. Its open screen area of 488 sq in. and 19 1/2-in. cutting circle allow large parts such as TV cabinets to be cut.

* Two high-speed granulators are new from the Conair Group. The 755HSSP, which uses two bed knives and four staggered rotating blades, can reportedly grind as much as 1500 lb/hr of roll scrap that is as wide as 55 in. Its sound enclosure reportedly reduces noise emission to between 85 and 90 db. The other unit, the MC 56, can handle as much as 8000 lb/hr of very large parts, Conair says. It has a 20-in. cutting circle.

* Two grinders from Foremost Machine Builders, Fairfield, N.J., debuted at NPE. Model 936 is a low-profile sheet and web grinder with a roller feeder inlet that can handle sheet 36 in. wide. Running at 600 rpm, the unit can reportedly reduce as much as 2000 lb/hr. Model HSFG is an eight-blade film grinder that uses straight knives to process up to 1200 lb/hr.

* Rapid Granulator, Rockford, Ill., introduced two new units: The 79 LBU, a belt-fed granulator with an adjustable height belt for easier feeding; and the 1418 KGB, a soundproofed granulator for long profiles and pipes.

* Ball & Jewell Div. of Sterling Inc., Milwaukee, redesigned its CG Series beside-the-press granulators with gas springs to tilt back the hopper and drop down the screen drawer at the touch of a button. These integrally soundproofed units come in four models from 8 x 12-ft to 16 x 32-ft chamber sizes.

FEEDING TECHNOLOGY

One of the more unusual introductions in metering and feeding was a system designed specifically for gravimetric ratio refeeding of film "fluff." The new Gravifluff feeder from Process Control Corp., Atlanta, is designed to eliminate surging and gauge variation caused by uneven fluff feeding. It has a fluff hopper mounted on a load cell for loss-in-weight feeding at a constant rate and a load-cell-mounted virgin hopper for gravimetric feeding to the extruder. The rate of fluff feed is determined by an auger and the virgin feed rate is guided by the screw speed. In addition, a fluff surge hopper atop the fluff feed hopper is mounted on its own load cell to turn a roll feeder on and off as needed. A 300-lb/hr, fluff-only system costs about $40,000, a spokesman says.

Another fluff feeder was introduced by K-Tron Vertech, Pitman, N.J. The unit has a digital load cell that uses a specially designed agitator to force fluff into the screw and discharge it directly into the extruder throat, which is said to eliminate cramming the feeder.

Labotek Inc., Briarcliff Manor, N.Y., debuted its Mini Conti-Master said to provide accurate metering and mixing of up to five different materials, concentrates, additives or regrind. Metering accuracy is between [+ or -]0.1% and [+ or -]0.5% depending on pellet size and shape, Labotek says. Maximum throughput is 250-260 lb/hr.

A pair of closed-loop additive feeders that deliver free-flowing material directly into the main process stream were introduced by Thoreson-McCosh Inc. These units are said to give accurate flow rations and are designed for quick access, easy flow-rate modifications and simple maintenance.

AEC/Whitlock introduced an auger-driven additive feeder with a supply hopper it says ensures a steady flow of material to the auger. For injection molding applications, the closed-loop control has a cycle timer that compensates for variations in the machine's screw rotation interval, AEC says.

METAL SEPARATORS & MORE

Several suppliers exhibited new units for removing metal from material. Universal Dynamics' new LCS (Last Chance Separator) is designed to be located right next to an extruder, giving processors a final opportunity to remove contaminants. Manufactured by Hamos Elektronik, Pennsberg, Germany, the LCS is available in four sizes, with inlets and outlets ranging from 1-to 4-in. diam.

Foremost Machine Builders introduced an in-line metal extractor that reportedly can detect ferrous and non-ferrous contaminants as small as 0.02-in. diam. The company also introduced a parts conveyor with a metal detector built in below the belt that stops the conveyor if a part contains any metal.

New parts conveyors were introduced by Crizaf Industrial Products, Inc., Sterling Heights, Mich. Crizaf, which makes more than 7000 conveyors/yr in Europe, showed its extruded aluminum frame conveyors and parts separators for the first time in North America (see PT, May '89, p. 179). Included in the company's offerings are the Model STN separator with a fixed roller and five separation points to achieve 100% separation of parts, sprues and runners; and an indexing conveyor for automatic production lines that require preset counting of components.

PHOTO : A new machine-mounted dryer from Thoreson-McCosh (above) has a microprocessor-controlled digital-display temperature control and operates on a single-blower, single-desiccant bed design.

PHOTO : A tubular diffuser (left), now standard on Novatec modular hoppers, provides uniform air flow with no detectable hot or cold spots in the resin.

PHOTO : Model STN separator from Crizaf Industrial Products uses a fixed roller and five separation points to completely separate parts, sprues and runners.

PHOTO : The direct-feed C-Loader from Conair bolts directly to the throat of an injection molding machine, eliminating the need for a dump valve or intermediate machine hopper.