Resin dryers: product lines reviewed.

AEC, INC.

See Whitlock

BRY-AIR SYSTEMS DIV. BRY-AIR, INC.

Offers resin dryers ranging in size from 12 to 5000 cfm. Larger dryers offer direct-fired, natural-gas regeneration for lower operating costs. All dryers feature multiple desiccant bed design.

Company also carries a line of mold dehumidification systems (MDS) to eliminate mold sweating. The MDS dryers range in size from 200 to 65,000 cfm. Resin powder drying systems are also available.

CACTUS MACHINERY INC.

Offers its line of Cactus Superdryers in four sizes for processing engineering resins at up to 75 lb/hr in 30 min from startup. An alternative to batch-type desiccant drying, the Cactus system operates on a continuous basis. Small amounts of resin are heated quickly to force the moisture to the pellet surface. A compressed air-powered venturi creates the air flow across the resin to transport the surface moisture from the resin. Low-wattage heater bands reportedly reduce the electrical consumption to 80% less than comparable desiccant dryers. Since there are no moving parts, maintenance is virtually eliminated. Microprocessor controls maintain accurate and constant temperature inside the dryer for consistent-quality parts. Predrying is not required. According to the company, material and/or color changes can be accomplished quickly and easily.

CARRIER VIBRATING EQUIPMENT

For drying various sizes and types of pellets, the company offers its 12-in. x 15-ft, 1-hp stainless-steel conveyor dryers with unit and hood insulation, and low profile to fit together with in-line equipment. Air temperature and volume are controlled to maintain pellet quality.

For drying PET chips in a bottle recycling process, company offers two-zone, stainless-steel, 2 x 10 ft, 2-hp, fluid-bed dryers, which are furnished as a system with auxiliaries, including steam coils, noise attenuators, dust collectors, slide gates, valves and discharge-drum covers. Air temperatures and volumes are controlled to dry chips to specified levels and prevent melting or fusing.

Tests on sample products are performed at company's laboratory facilities, or rental packages are available for in-plant testing to set design parameters for unusual applications.

CARTER DAY INDUSTRIES (CANADA)

Company's SpinAway Dryer is a centrifugal dryer for cost-effective drying of plastic flakes or pellets. Capacities range from 100 to 110,000 lb/hr, drying to moisture levels to less than 0.05%. Dryer has reinforced rotor-lifter-plate design for extended rotor life. Logarithmic lifter-blade spacing in the rotor design increases the pellet resident time, enhancing drying; and the horizontal airflow forces water and air through the screen rather than out the pellet discharge. The unit requires minimal space, low horsepower, and is designed for continuous, uninterrupted production. Accessories include dewatering units, moist-air exhaust fans, air pre-heaters, internal washdown spray systems, hardened rotors, pellet-free rotors, and low-noise construction.

CINCINNATI MILACRON U.S. PLASTICS MACHINERY DIV.

Offers a comprehensive line of dehumidifying dryers that are machine mounted, portable, or floor mounted. The complete line has air-flow ratings of 25 to 2500 cfm. Modular, insulated stainless-steel hoppers are sized to the requirement and designed for balanced flow of dry air. Also included are an aluminum mounting casting at the throat and a slide gate. Microprocessor controls feature large digital display of set and actual temperature, alarm codes, and cam-cycle sequence codes. The units utilize a solid-bed design with low-watt-density Calrod heaters. Options include: hi-temp package (300-400 F); hopper-mounted process-air heater, and precooling coil. Hopper options include drawer magnet, vacuum take-off, and low-level alarm.

COLORTRONIC

See K-Tron, Colortronic & Co.

COMET AUTOMATION SYSTEMS INC.

Series SD dryers dry resins at a rate of 15-25 lb/hr. Dual desiccant beds provide a low dewpoint of -40 F with a completely automatic regeneration cycle. Space-saving construction permits on-machine or separate mounting. Solid-state temperature control enhances reliability.

CONAIR FRANKLIN THE CONAIR GROUP, INC.

Mini-dryers for throughputs up to 70 lb/hr feature standard microprocessor control and "true" closed-loop design for desiccant cooling, unlike ordinary twin-tower designs that utilize ambient moisture-laden air.

Carousel series of dryers, for throughputs of over 70 lb/hr, features rotating multiple desiccant cartridge design that reduces the temperature and humidity spikes found on ordinary twin-tower designs. This design also features true closed-loop desiccant cooling after regeneration, eliminating preloading of desiccant with ambient moisture.

CompuDry II Axiometer R in-line resin moisture monitoring system is said to be the first in-line resin moisture analyzer that is integrated with the dryer's control to give the processor complete closed-loop moisture feedback and temperature control.

A line of six gas-heated resin dryers is available in capacities to dry from 300 to 4000 lb/hr. Other features include temperature control within |+ or -~2|degrees~ F; a radiant burner designed for efficient heat transfer and low emissions; and compliance with National Fire Protection Association (NFPA) standards.

J.H. DAY CO./TAYLOR STILES 

Offers a choice of product dryers and drying systems for resin powders, pigments, pellets and other particulates in conjunction with mixing, blending, processing and reaction. Large cylindrical dryers can process up to 1000 cu ft/batch with a choice of full or partial jackets in a variety of designs for heat transfer and/or full internal vacuum or pressures to 200 psi.

Vertical conical Day Mark II processor/mixer drying systems can handle up to 1400 cu ft/batch. Jacketed, vacuum or pressure designs are available.

DRI-AIR INDUSTRIES, INC.

Manufactures a complete line of desiccant dryers and drying systems for throughputs from 2 to 400 lb/hr. Company's Arid-X series dryer is a fully automatic dual-bed design which produces -40 F dewpoint air for engineering resins and is offered in barrel-mounted and floor-standing models.

The Arid-X 10 for small molding machines or laboratory applications will dry up to 10 lb/hr and measures only 9 x 14 x 16 in. high. It is available in 110 or 220 volts. Hopper sizes as low as 5-lb capacity can be supplied.

Portable drying systems are offered to reduce downtime for material changes. Systems integrate dryer, hopper and closed-loop loader on a compact, castered frame. A small receiver replaces the machine hopper and is easily removed for cleaning. Company will customize equipment design.

FLUID AIR INC.

Offers stainless-steel, batch fluid-bed dryers used for food, pharmaceuticals and fine chemicals. Models range up to 1450-liter batch size. Pilot facilities for feasibility testing are available.

FOREMOST MACHINE BUILDERS

Company offers dehumidifying hopper dryers in a wide range of drying capacities. The design reportedly uses less electricity than conventional units for equivalent throughput. Features include crossflow regeneration for extremely low dewpoints with no spikes. Standard high-heat/PET models are also available.

GRUENBERG OVEN CO., INC.

Granulate dryers up to 500 F, with a uniformity of |+ or -~9|degrees~ F, are available in truck-load or shelf-load design. Stainless-steel interiors, continuously welded liners, and HEPA filtration are some standard features to prevent contamination. Explosion-resistant design is optional. Custom-designed units can be built to meet specific application.

A.C. HAMILTON, INC.

Offers its Accudry series of dehumidifying dryers for critical drying applications, and its 2000 series of hot-air dryers for new hygroscopic applications.

Ten models of automatic desiccant dryers are offered. These use a molecular-sieve desiccant to trap moisture within a closed drying system. Several desiccant cartridges are provided, which are periodically indexed to a regeneration cycle. Programmable microprocessor controls provide LCD messages for initial settings and provide performance information, as well as alarm conditions.

Hot-air dryers come with an integrated, stainless-steel-lined drying hopper, which mounts on the processing machine. Floor-mounted models are available. Seven models provide drying ranges from a few lb/hr to more than 1000 lb/hr, depending on material type. An air-flow regulator balances blower cfm for drying efficiency.

HYDRECLAIM CORP.

Hydra-Dry Series of dehumidifying drying systems feature a single rotary, molecular-sieve desiccant honeycomb wheel offering lower energy consumption, smaller size, lower stable dewpoint capability, and efficient use of desiccant material. Elimination of desiccant dusting and controlled laminar airflow with minimal pressure drop through desiccant are also claimed, as are lower maintenance with fewer moving parts, no temperature blips, no valves, easy troubleshooting.

IMS CO.

Offers three styles of hopper dryers for use at the press. Model MD-100 is a low-cost, hot-air unit for use with nonhygroscopic materials and can serve more than one press. Model MD-750-50 is a refrigerant/hot-air dryer suitable for many hygroscopic materials. RD-Series desiccant dryers use four rotating desiccant beds to ensure consistently low dewpoint. A variety of convection, refrigerant/hot-air dehumidifying and desiccant-type drying ovens are also available.

JEFFREY DIV. DRESSER INDUSTRIES, INC.

Offers a full line of vibrating fluid-bed dryers and coolers. The vibrating fluid-bed system efficiently transfers heat and mass. The advantage of intimate contact between material and the air stream of the fluid bed are combined with the gentle handling and positive conveying action of a vibrating conveyor to create versatile equipment. Some features include self-cleaning design with stainless-steel contact surfaces, variable conveying speeds, automatic control, inspection doors, and multisection air plenum.

To ensure proper equipment sizing, company offers on-site testing, utilizing skid-mounted rental units. In addition, it can provide full-size, continuous-run testing at its test laboratory facilities.

K-TRON, COLORTRONIC & CO.

Company offers a full line of central dehumidifying dryers, as well as machine-dependent dryers. Colortronic dehumidified-air dryers are designed to dry granular thermoplastics to the lowest residual moisture content possible, regardless of atmospheric conditions. Dryers are said to achieve good drying results with the minimum energy requirement. Company also offers insulated drying hoppers to further reduce energy costs. Continuous dewpoint sensing also saves energy, as heating for drying occurs only when necessary. Dewpoint of dehumidified air from regenerated desiccant cells is -40 to -76 F. Dryers use stainless-steel heating elements and cast desiccant beds for longer life.

LABOTEK INC.

Desiccant Dryer/Loaders (DDL) combine loading, desiccant drying, and automatic regeneration in one compact unit. Units have floor-mounted control panel with functions displayed by graphics and light signals, and achieve residual moisture levels down to 0.02%. They operate on low power, have hopper-magnet shut-off slide valve, discharge valve for easy material change, and come in nine sizes. Company also offers its DDL-HT for drying PET bottle resins to moisture levels of 0.002%.

Mobile Desiccant Dryer/Loaders (DDM) combine in one mobile unit the dryer, desiccant, automatic regeneration, and automatic conveying of dried material to process machine, using predried hot air. Special discharge fitting acts as level control on process machine hopper. DDM can feed two process machines at the same time. Unit is available in three sizes and is loaded with material to be dried by company's Con-Evator three-phase hopper loader.

Desiccant Central Dryer (DCD) dries one or more granular materials to less than 0.02% moisture in one or more drying hoppers, using a central power pack, which comes in six sizes. Hoppers have individual heaters and temperature controllers, making it possible to dry different materials at the same time.

LYDON BROTHERS CORP.

A custom industrial oven manufacturer offering three standard sizes of electrically heated, resin-tray drying ovens.

Model 1330-1-T3 is a 12-tray small lab size with average capacity of 100 lb; Model 1330-2-T3 is a medium 24-tray unit with 150-lb average capacity; and Model 1330-5-T3 is a 40-tray unit with capacity up to 600 lb.

Standard systems include indication of temperature to 350 F, timer, and high limit. Options are available to customize ovens to the process, including desiccant systems, dewpoint instruments, recorders, chillers and filtration.

MATSUI AMERICA, INC.

DMZ series of dehumidifying hopper dryers and central drying systems utilize a "honeycomb" rotary desiccant bed of molecular-sieve desiccant bonded to ceramic paper, which slowly turns three times/hr, repeating a cycle of regeneration, heating, cooling and dehumidification. Low dewpoints of -40 F are said to be easily maintained. Microcomputer control has membrane keys and optional communications with host computer and/or molding machine controller. The smallest model can handle 1412 cu ft/hr.

Also available are the HD II hot-air hopper dryer, with 22-660 lb hopper capacity; the Shot Dryer, which saves energy by using heat from the barrel to aid drying; a microwave-type dryer, which is reportedly much faster than conventional types; and the MultiJet II, which combines a hopper loader, dehumidifying hopper dryer, and mold-temperature controller in one compact, mobile console.

MOTAN, INC.

Company's dehumidifying dryers include capacities ranging from 15 to 1000 cfm. All units include simple design, employing positive-seating valves for air routing, alarm functions, and user-friendly controls. Larger models feature microprocessor controls and available dewpoint monitoring/control of dryer functions. Company specializes in central drying systems.

NISSUI CORP.

Offers two lines of dryers:

* Mach I microwave dryer, which dries plastic from within. Energy costs and drying time are reportedly reduced by 50% when compared with conventional methods. Dryer crystallizes PET in the drying process.

* Dezat dryer, which does not use a desiccant bed. The unit is easy to clean with less time lost for changeover.

NOVATEC INC.

Offers a full range of standard dryer and hopper configurations and designs custom drying systems. Electromechanical controls with a solid-state PID temperature controller are standard; a choice of microprocessor controllers is available as options.

Machine-mounted or floor-stand mounted hopper/dryer packages with capacities from 15 to 50 lb/hr utilize a dual-tower process with fully automatic regeneration. Modular stainless-steel hoppers are standard in either insulated or noninsulated versions. Optional microprocessor controls are available with a dual seven-segment LED display or 40-character alphanumeric vacuum-fluorescent display.

Floor-mounted drying systems with capacities from 50 to 4000 lb/hr and hopper capacities from 200 to 10,000-plus lb may be equipped with an optional microprocessor controller. It has an 80-character alphanumeric vacuum fluorescent display, which monitors and controls 51 drying functions, displaying messages and corrective actions. Other features include a "help" key, pass-code access and a Quick-Set menu, which allows preprogramming of drying parameters for up to 10 different resins.

PLASTICS ANCILLARIES CORP.

Offers a complete line of dryers, all with dual regenerating desiccant beds, and fully insulated hoppers.

PROCESS CONTROL CORP.

Manufactures a complete line of dryers and crystallizers for processing hygroscopic, nonhygroscopic and amorphous materials. For drying hygroscopic materials, the desiccant dryers include the following features:

* Closed-loop cooling of the regenerative cycle avoids depositing water from atmospheric air, while cooling a bed after regeneration.

* Co-current (downward) flow of drying and regeneration air avoids the possibility of lifting or fluidizing desiccant pellets, which cause air bypass and pellet wear. Co-current design avoids dewpoint blips that result from counter-current systems.

* Passing hot exhaust air from the regeneration circuit through a heat exchanger transfers up to half the otherwise wasted heat to the active circuit, thus reducing power requirements on the active heating circuit.

* Because of the hopper design, only 0.6 cfm per lb/hr of material is required.

* Heater-box design results in cool outer-shell temperatures and minimal heat loss. Mounting the drying-air heater directly on the dryer hopper reportedly saves energy and provides more accurate temperature control.

* Insulated desiccant towers are said to save energy and minimize time required for initial heat-up.

Company also carries a line of single-stage, hot-air drying systems for processing nonhygroscopic materials. They are often used as a low-cost, first-stage drying system for high-rate processing of hygroscopic materials.

For amorphous PET pellets or scrap, company offers the HC Series crystallizers, designed to continuously agitate the material during crystallizing, thus preventing agglomeration of the resin.

REGENCY SALES, INC.

Offers a dehumidifying dryer that is said to streamline the drying procedure. A drying bed of molecular sieves bonded to ceramic paper gives a clean-drying low dewpoint (-40 F) without the aid of a chiller. The drying bed has a high void ratio and features low pressure drop. Low backpressure and no channeling, innovative in drying systems, reduce required times up to 30%.

TEW ELECTRIC HEATING EQUIPMENT (USA) INC.

Offers six models of hopper dryers with even heat distribution, accurate temperature controller, and capacities from 25 to 880 lb/hr. A dust-collector attachment is available.

Also offers a double-desiccant, regenerating dehumidifying dryer that reduces moisture to -40 F dewpoint. Unit comes complete with a snake cooler and 110-lb double-insulated hopper.

THORESON-MCCOSH, INC.

Offers its Dri-Pak 12/24 compact hopper and dryer unit designed for mounting on the feed throat of an injection molding machine. The system requires no floor space. Dri-Pak is built in two sizes: a 12 cfm unit with drying capacity of 12-15 lb/hr and hopper capacity of 48 lb at 35 cu ft bulk density; and a 24 cfm unit with drying capacity of 24-30 lb/hr and hopper capacity of 100 lb.

Dryers feature a single-bed single-blower system, featuring a high-pressure regenerative blower. System is "off-stream" for 11% of the total cycle time for regeneration. Airflow during the process cycle is increased so that average cfm is at least equal to the dryer rating. System has a microprocessor-controlled digital temperature display. Insulated hoppers for both sizes are optional.

Company also provides a line of resin dryers matched to hoppers designed to uniformly expose resin to drying air. They include TD series of desiccant dryers available in 16 models with airflows from 12 to 2000 cfm. Units feature an indexing, three-bed design with closed process-air circuit. Design allows in-process cool-down of the regenerated bed with recovery of residual regeneration heat and cool-down with the dry process stream rather than with ambient air. Tech II microprocessor control is available as an option. Control includes a seven-day timer with battery back-up, display of dryer operating parameters, alarms and system-operating diagnostics.

Refrigeration or "R" series dryers are available in nine sizes from 50 to 2000 cfm. Units remove moisture from the process stream by passing air over a refrigerant coil and removing any moisture in excess of the saturated air temperature by condensation. Evaporator coil temperatures must be kept at a temperature above freezing, which results in a discharge dewpoint of approximately -45 F. Dryers are particularly suitable for materials such as butyrate, which give off a plasticizer.

HotAir or "H" series dryers are available in 11 sizes with airflows of 12 to 2000 cfm. Units heat and circulate air through the resin, removing any surface moisture, and are intended for use on nonhygroscopic materials. They are often used to remove condensation from materials brought into a warm plant from cold storage.

UNIVERSAL DYNAMICS CORP.

Manufactures a complete line of materials dryers, including the DHD series dehumidifying hopper dryer with process airflow up to 3000 cfm and low dewpoint to -40 F. Unit has a minimum of moving parts; and quick-access clamps provide easy access in a matter of minutes to the regeneration heater, process heater, and desiccant beds. Heater packages utilize tubular elements, double-wall construction and insulation, and are designed for safety and efficiency. Tubular heaters with low watt-density increase heater life. Multiple elements allow the heater to operate when an individual heater fails. The DHD series comes with Omni II-E microprocessor control. An advanced closed-loop Omni II-X control is optional. Both controls come with SPI communications protocol capabilities. Hoppers range in capacity from 300 to 12,000 lb.

Company also manufactures a complete line of dehumidifiers and hot-air drying systems.

WALTON-STOUT, INC.

Manufactures dehumidifying desiccant dryers with microprocessor controller. Standard features include dewpoints of -40 F; electronic temperature control; process-air filter with cyclone and cartridge; cycle rates of 8, 12, and 16/hr; no moving parts except two four-way valves in the blowers; hopper clean-out door and large sight glass; 85 through 3000 cfm size range with hopper capacities up to 12,000 lb; direct-drive fans; location of desiccant inside towers and heaters outside in separate boxes; and drawer-type process-air heaters mounted externally.

Microprocessor-based control panel is available with complete graphic presentation. The panel controls and monitors all dryer functions. Process-air temperature is selected manually and then precisely maintained with solid-state electronic temperature control.

Company also manufactures hot-air dryers and preheater units for use with nonhygroscopic materials from 85 through 3000 cfm. Units have solid-state electronic temperature controls. Process heaters, mounted externally, are drawer-type that slide in and out. All units are accessible from the exterior, furnished with direct-drive fan, and compact.

WHITLOCK/AEC, INC.

Offers a complete line of hot-air and dehumidifying drying systems featuring microprocessor-based temperature controls. Company's HA series of hot-air dryers range from 30 to 2500 cfm for processing nonhygroscopic materials.

The SB, WD and DB series of dehumidifying dryers range in size from 10 to 2500 cfm and feature twin stationary desiccant beds to ensure an uninterrupted flow of dehumidified air.

Also available to complete the systems are a full line of drying hoppers from 50- to 10,000-lb capacities, after-coolers, pneumatic conveying equipment, blenders and other related materials-handling accessories.

THE WITTE CO., INC.

Offers a continuous vibrating fluid-bed dryer consisting of a totally enclosed vessel with a porous conveying surface. The latter permits air or gas to pass up through the vibrating bed of material, which results in maximum air contact with particle surfaces for efficient drying while still maintaining first in/first out retention. Other important features are ease of cleaning and gentle handling of the product, so that there is zero to negligible particle degradation.

Company maintains a testing laboratory where drying data gathered are used for straight ratio size-up and do not require further extrapolation for designing full-scale production equipment.

WYSSMONT CO., INC.

Company's Turbo-Dryer has only two moving parts: tray/shelf assembly and fan assembly, both rotating independently in a fixed sealed housing.

Wet feed enters the Turbo-Dryer through a feed chute in the roof of the housing and flows onto the first shelf. Shelves are circular with cut-out center and radial slots. They are rigidly mounted on an inner supporting frame, forming a vertical stack, which rotates slowly as a unit. Material flows onto each shelf from the one above, forming a pile. The rotation of the tray/shelf assembly carries the pile past a stationary blade set to level the pile to fill the tray at a uniform height. At the end of a revolution, the tray segment meets a second stationary blade set to wipe the tray clean of material. The material is held stationary by the wiper blade, while the tray continues its rotation. The material flows through the radial slot onto the shelf below, where the cycle is repeated. Material progresses downward from shelf to shelf through the dryer and is discharged through a chute in the housing bottom.

Air or other drying medium is fed to the Turbo-Dryer through a side-mounted vertical manifold with control dampers. Air movement inside the dryer is provided by centrifugal fans mounted on a single vertical shaft. The fan assembly fits in the center of the shelf assembly, rotating independently of the shelves. The drying medium leaves the dryer through a roof exhaust.

The Turbo-Dryer housing, totally sealed, encloses and supports both tray/shelf and fan assemblies; supports stationary parts of the dryer, wipers and levellers; and consists of a metal frame and insulated side panels, roof, and bottom.

Heaters for the Turbo-Dryer can be mounted internally in the space between the shelves and the housing, or externally in the air-supply system.