AUXILIARY EQUIPMENT: Small Desiccant Wheel Dryers For Machine-Mounting, Low-Throughput

Billed as alternative to compressed-air and small twin-tower units.

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The new MicroWheel dryers from Conair, Cranberry Township, Pa., are said to deliver the efficiency and precision of desiccant-wheel drying in a compact configuration that can be mounted on the feed throat of a molding machine or extruder. Thought to be the smallest wheel dryers available, they offer an alternative to compressed-air dryers and small twin-tower units, reportedly making them suited for medical processors and others running small quantities of expensive engineering resins.

The new dryers are offered in two basic models: the MW1 and the MW2. Because they use brushless blowers with speed control built in, the dryer can be easily programmed to deliver exactly the right amount of process air flow to dry the different resin volumes. Each model is available with several different hopper capacities. The MW1 units can support hoppers of 0.2 ft³ 0.5-ft³ and 1 ft³ capacity. Including the hopper, they range in height from 19.5 in. to 27.7 in.; the largest weighs 106 lb. 

The speed-controlled blower, along with a highly-intelligent control, makes it possible to fine-tune drying parameters to achieve perfectly dried material with a minimum of energy input and little chance of over- or under-drying. The control comes pre-programmed with 30 different recipes for various resins. The user simply identifies the material being dried along with the expected throughput and the control automatically adjusts temperature and airflow to match resin-supplier guidelines for effective drying. In addition, there is storage space for 20 user-defined recipes, which can be variations on the preset recipes or entirely new programs created by the processor.

Other standard control features include:

1. Material Protection Management (MPM) system, which automatically reduces process air temperatures when return-air temperatures exceed setpoint. This is usually an indication that throughput rate has dropped and that material is not being withdrawn from the drying hopper as fast as anticipated. This standard temperature setback feature saves energy and prevents over-drying.

2. Real-Time Energy Consumption Monitoring, which tracks the dryer’s power consumption, allowing users to fine-tune energy use while maintaining proper drying conditions. Factoring in electric rates, processors can calculate how much power is needed to produce a given quantity of parts.

Standard stainless-steel hopper liners are fully insulated, with a protective aluminum outer shell. A stainless-steel machine-throat adapter, with resin-discharge port and purging compound input bypass port, is available optionally.