Resin dryers: product lines reviewed.

RESIN DRYERS

PRODUCT LINES REVIEWED

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

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

CACTUS MACHINERY INC.

Offers its line of resin dryers called Cactus Superdryers. Four sizes are available for processing engineering resins at up to 75 lb/hr in 30 min. An alternative to desiccant drying, the Cactus system operates on a continuous basis as opposed to batch drying. Small amounts of resin are heated quickly to force the moisture to the pellet surface. Waste heat from the barrel accomplishes much of the drying. 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. The newly developed microprocessor controls maintain an accurate and constant temperature inside the dryer for consistent quality parts. Predrying is not required. The Cactus Superdryer is ready to produce dry resin in 30 min and, according to the company, material and/or color changes can be accomplished quickly and easily.

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 80,000 lb/hr with moisture levels to less than 0.05%. The logarithmic turbine design has a series of stepped plates which carry the pellets or flakes rapidly upward in an even flow, allowing for greater capacity while requiring less space and only a low-horsepower motor with minimal energy requirements. Accessories available include dewatering units, moist-air exhaust fans, air preheaters, internal washdown spray systems, hardened rotors, pellet-free rotors, and low-noise construction.

CINCINNATI MILACRON U.S. PLASTIC MACHINERY DIV.

Offers a comprehensive line of resin dehumidifying dryers that are machine mounted, portable, or floor mounted. The complete line has an air-flow rating of 25 to 2500 cfm. Modular, insulated stainless-steel hoppers are sized to the requirement and design for balanced flow of dry air. Also included is an aluminum mounting casting at the throat and a slide gate. Microprocessor controls feature large digital numerical 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.

COMET AUTOMATION SYSTEMS, INC.

Company's series SD dryers operate at a rate of 15-25 lb/hr. Dual desiccant beds provide a low dewpoint of -40 F to allow a completely automatic regeneration cycle. Space-saving construction permits on-machine or separate mounting for convenience. Solid-state temperature control enhances reliability.

THE CONAIR GROUP, INC.

Mini-dryers for throughputs up to 70 lb/hr, and the new mini-dryer line (CD-30 and CD-60 models) feature an updated standard microprocessor control at no extra cost for 1990. Units reportedly also feature the industry's only true closed-loop design for desiccant cooling, unlike ordinary twin-tower designs that utilize ambient moisture-laden air for this process.

The Carousel series of dryers, for throughputs of over 70 lb/hr, have several improvements for 1990. The series features the rotating multiple desiccant cartridge design that reduces the temperature and humidity spikes found on ordinary twin-tower designs. Additionally, this design features true closed-loop desiccant cooling after regeneration, which eliminates preloading of desiccant with ambient moisture.

New for 1990, company has announced the CompuDry II Axiometer R in-line resin moisture monitoring system. System is said to be the first in-line resin moisture analyzer that is integrated in the dryer's control to give the processor complete closed-loop moisture feedback and temperature control.

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 the newer 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.

Closed-loop conveying systems are custom-designed to allow the drying hopper to be floor-standing with a small receiver located on the feed throat. This system allows for faster changeovers, easier cleaning, or one drying system to feed several machines. Systems are available for handling from 2 to 300 lb/hr. Loaders and magnet drawers, which mount to the drying hoppers, are also supplied. Company will custom design.

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 cross-flow regeneration for extremely low dewpoints with no spikes. Standard/high-heat/PET resin models are also available.

GRUENBERG OVEN CO., INC.

Granulate dryers up to 500 F, with a uniformity of +/-9 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 customer's application.

A.C. HAMILTON, INC.

Offers its 2000 series of hot-air dryers or computer-controlled dehumidifying dryers for critical drying applications.

The 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. The design includes an air-flow regulator to balance blower cfm for drying efficiency.

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.

IMS CO.

Offers two 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-type dehumidifying hopper dryer designed for hard-to-dry materials such as nylon.

For maximum moisture removal, Company also offers a wide variety of convection and desiccant-type thermoplastic drying ovens.

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 a versatile piece of processing equipment, which the company says is suited to plastics. Some features include self-cleaning design with stainless-steel contact surfaces, variable conveying speeds, automatic control, inspection doors, multisection air plenum, design and temperature flexibility.

To insure 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.

LABOTEK INC.

Offers the following:

* Desiccant Dryer/Loaders (DDL)--Combine loading, desiccant drying, and automatic regeneration in one compact unit. Has floor-mounted control panel with various functions displayed by graphics and light signals. Achieves residual moisture levels down to 0.02%. Operates on low power, has hopper magnet shut-off slide valve, discharge valve for easy material change, and is available 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: 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 plastics granule 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.

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 an hour, repeating a cycle of regeneration, heating, cooling and dehumidification. Low dewpoints of -40 F are said to be easily maintained. Microcomputer control panel has membrane keys and optional communications with host computer and/or molding machine controller. Smallest model handles 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 that 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 introduces microwave technology to dry plastic from within. Energy costs and drying time are reportedly reduced by 50% when compared to conventional methods. Dryer crystallizes PET in the drying process.

* Dezat dryer does not use a desiccant bed, and therefore requires no maintenance. The unit is easy to clean with less time lost for changeover.

NOVATEC INC.

Offers microprocessor-controlled dryers with diagnostics in 80-character, alpha-numeric, user-friendly messages. Machine-mounted hopper/dryer packages with capacities from 15 to 50 lb/hr utilize the efficient dual-tower process with fully automatic regeneration. Floor-mounted drying systems with 50 to 4000 cfm capacities and hopper capacities from 50 to 10,000 lb and more are available with a multitude of standard features, as well as options.

Company's Central Dryer System is a multi-hopper and heater arrangement using a single dryer that provides custom drying of different resins simultaneously.

The MCD-1001 microprocessor controller features monitoring of 51 drying functions, clear corrective action messages, a menu which allows preprogramming of the drying parameters of up to 10 different resins, a "help" key, dryer access by special pass code, and energy-saving benefits.

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, company's Thrifti-Dri system includes 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.

* Requires only 0.6 cfm per lb/hr of material because of the hopper design.

* 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, which are often used as a low-cost, first-stage drying system for high-rate processing of hygroscopic materials.

A patented crystallizer for processing amorphous PET is also available.

REGENCY SALES

Offers a dehumidifying dryer that is said to streamline the drying procedure. A 10-15 year drying bed of molecular sieves bonded to ceramic paper gives a clean-drying low dewpoint (-40 C) without the aid of a chiller. The drying bed has a high void ratio and features low-pressure loss. Low backpressure and no channeling, innovative in drying systems, reduce required times by up to 30%.

THORESON-McCOSH, INC.

Provide a complete line of resin dryers with three basic series and 36 models.

* TD series of desiccant dryers, available in 16 models with airflows from 12 to 2000 cfm, features 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 cooldown with the dry process stream rather than with ambient air. The Tech II microprocessor control is available as an option on all TD dryers. Control includes a seven-day timer with battery backup, 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 regrigerant 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. Air, when heated to the typical drying temperatures, results in relative humidities of 1% or less and will effectively dry all but the most hygroscopic materials. "R" dryers are particularly effective on materials such as butyrate, which gives off a plasticizer.

* HotAir or "H" series dryers are available in 11 sizes with airflows for 12 to 2000 cfm. They 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 the condensation from materials brought into a warm plant from cold outside storage.

All dryers are matched to hoppers designed to uniformly expose resin to the drying air.

UNIVERSAL DYNAMICS CORP.

Manufactures a complete line of material dryers, including its 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 the desiccant beds. Heater packages, which utilize tubular elements, double-wall construction and insulation, are designed for safety and efficiency. Tubular heaters, with very low-watt density, increase heater life. Multiple elements allow the heater to operate when an individual heater fails. The DHD series is complete with a state-of-the-art Omni II-E microprocessor control. An advanced closed-loop Omni II-X control is available as an option. 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. (See ad p. 315.)

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 times of 8, 12, and 16 hr.

* No moving parts except two four-way valves and the blowers.

* Hopper clean-out door and large sight glass.

* Eighty-five through 3000 cfm size range with hopper capacities up to 12,000 lb. Larger sizes are available.

* Direct-drive fans--no belts, no sheaves.

* Only desiccant located inside towers. All heaters are located outside in separate boxes.

* Process-air heaters mounted externally are drawer-type, which slide in and out.

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

WHITLOCK DIV. 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 1000 cfm for processing nonhygroscopic materials.

The SB, WD and DB series of dehumidifying dryers range in size from 12 to 1000 cfm and feature twin stationary desiccant beds to insure an uninterrupted flow of dehumidified air to the product.

Also available to complete the systems are a full line of drying hoppers from 50- to 6000-lb capacities, aftercoolers, 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 porous-conveying surface 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. The product is handled so gently 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. The shelves are circular with cut-out center and radial slots. Shelves 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 freshly formed 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 and rotates independently of the shelves. The drying medium leaves the dryer through a roof exhaust.

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

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. [Data Sheet Omitted]